WorldWideScience

Sample records for superposition compound eyes

  1. Partial coherence and other optical delicacies of lepidopteran superposition eyes

    NARCIS (Netherlands)

    Stavenga, DG

    2006-01-01

    Superposition eyes are generally thought to function ideally when the eye is spherical and with rhabdom tips in the focal plane of the imaging optics of facet lenses and crystalline cones. Anatomical data as well as direct optical measurements demonstrate that the superposition eyes of moths and

  2. Optics and phylogeny: is there an insight? The evolution of superposition eyes in the Decapoda (Crustacea)

    NARCIS (Netherlands)

    Gaten, Edward

    1998-01-01

    This paper addresses the use of eye structure and optics in the construction of crustacean phylogenies and presents an hypothesis for the evolution of superposition eyes in the Decapoda, based on the distribution of eye types in extant decapod families. It is suggested that reflecting superposition

  3. A cute and highly contrast-sensitive superposition eye : The diurnal owlfly Libelloides macaronius

    NARCIS (Netherlands)

    Belušič, Gregor; Pirih, Primož; Stavenga, Doekele G.

    The owlfly Libelloides macaronius (Insecta: Neuroptera) has large bipartite eyes of the superposition type. The spatial resolution and sensitivity of the photoreceptor array in the dorsofrontal eye part was studied with optical and electrophysiological methods. Using structured illumination

  4. A cute and highly contrast-sensitive superposition eye - the diurnal owlfly Libelloides macaronius

    NARCIS (Netherlands)

    Belusic, Gregor; Pirih, Primoz; Stavenga, Doekele G.; Belušič, Gregor; Pirih, Primož

    2013-01-01

    The owlfly Libelloides macaronius (Insecta: Neuroptera) has large bipartite eyes of the superposition type. The spatial resolution and sensitivity of the photoreceptor array in the dorsofrontal eye part was studied with optical and electrophysiological methods. Using structured illumination microsco

  5. Invertebrate superposition eyes-structures that behave like metamaterial with negative refractive index

    NARCIS (Netherlands)

    Stavenga, D. G.

    2006-01-01

    The superposition eyes of moths and lobsters are described with the geometrical optics for a refractive surface between two media, where the refractive index of the image space is negative. Consequently, the eye power and the object focal length are negative, whereas the image focal length is positi

  6. Invertebrate superposition eyes-structures that behave like metamaterial with negative refractive index

    NARCIS (Netherlands)

    Stavenga, D. G.

    2006-01-01

    The superposition eyes of moths and lobsters are described with the geometrical optics for a refractive surface between two media, where the refractive index of the image space is negative. Consequently, the eye power and the object focal length are negative, whereas the image focal length is

  7. Miniature curved artificial compound eyes.

    Science.gov (United States)

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-04

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories.

  8. Botanical Compounds: Effects on Major Eye Diseases

    Directory of Open Access Journals (Sweden)

    Tuan-Phat Huynh

    2013-01-01

    Full Text Available Botanical compounds have been widely used throughout history as cures for various diseases and ailments. Many of these compounds exhibit strong antioxidative, anti-inflammatory, and antiapoptotic properties. These are also common damaging mechanisms apparent in several ocular diseases, including age-related macular degeneration (AMD, glaucoma, diabetic retinopathy, cataract, and retinitis pigmentosa. In recent years, there have been many epidemiological and clinical studies that have demonstrated the beneficial effects of plant-derived compounds, such as curcumin, lutein and zeaxanthin, danshen, ginseng, and many more, on these ocular pathologies. Studies in cell cultures and animal models showed promising results for their uses in eye diseases. While there are many apparent significant correlations, further investigation is needed to uncover the mechanistic pathways of these botanical compounds in order to reach widespread pharmaceutical use and provide noninvasive alternatives for prevention and treatments of the major eye diseases.

  9. Spatial Information Capacity of Compound Eyes

    NARCIS (Netherlands)

    Snyder, Allan W.; Stavenga, Doekele G.; Laughlin, Simon B.

    1977-01-01

    The capacity of the compound eye to perceive its spatial environment is quantified by determining the number of different pictures that can be reconstructed by its array of retinula cells. We can then decide on the best compromise between an animal's capacity for fine detail and contrast sensitivity

  10. Development of the compound eyes of dragonflies (Odonata). III. Adult compound eyes.

    Science.gov (United States)

    Sherk, T E

    1978-01-01

    The distribution of ommatidial diameters and interommatidial angles, as determined by measuring the angles between the optic axes of adjacent ommatidia, are mapped across the surface of the compound eyes of a variety of species selected for different adult behaviors, developmental histories, and taxonomic positions. The size of the visual fields, prey capture foveas, foveas composed of large dorsal ommatidia, and other specializations in the numbers of ommatidia that view various directions in the visual field are discussed in relation to adult behavior. Advanced species have less resemblance between their larval and adult eyes than primitive species. In contrast to their larvae, adults increase the monocular resolution of each eye at the expense of binocular vision. Most species have foveas which view in approximately the anterior direction, instead of in a region of binocular overlap, and many species have foveal bands which view along the horizon. Some advanced perching species, which approach their prey and other odonates from below, have an additional vertical foveal band that views along a vertical plane from the anterior direction to a more dorsal direction. The most unusual foveal band is seen in active flying species. The large dorsal ommatidia of the migratory Anax junius, which cover approximately one third of the eye surface, view a narrow region of the visual field that extends along a plane from the most lateral direction of one eye to a dorsal direction, and continues without interruption to the most lateral direction of the other eye.

  11. Development of the compound eyes of dragonflies (Odonata). II. Development of the larval compound eyes.

    Science.gov (United States)

    Sherk, T E

    1978-01-01

    The development of the compound eye was analyzed by marking individual ommatidia and by studying naturally occurring pigment band patterns. New ommatidia are added to the eye along its anterior margin. This changes the directions of view of the older ommatidia with the greatest change occurring in the fovea. New ommatidia are added to the fovea medially, and old ones are removed laterally as their interommatidial angles and directions of view in the visual field change. Over one-third of the aeshnid ommatidia are foveal during at least one of the early larval instars, and are then used for peripheral vision later in development. The design of each ommatidium is a compromise so that it is adapted for all stages of development, but sometimes better adapted for one instar than for others. Factors which are balanced for best vision are lens diameter, facet admission function, interommatidial angle, and inclination of the optic axis to the eye surface. Ommatidia are described in terms of these factors throughout their life history, from initial differentiation anteriorly, through passage through the fovea, to their final relatively posterior location.

  12. Light emission from compound eye with conformal fluorescent coating

    Science.gov (United States)

    Martín-Palma, Raúl J.; Miller, Amy E.; Pulsifer, Drew P.; Lakhtakia, Akhlesh

    2015-03-01

    Compound eyes of insects are attractive biological systems for engineered biomimicry as artificial sources of light, given their characteristic wide angular field of view. A blowfly eye was coated with a thin conformal fluorescent film, with the aim of achieving wide field-of-view emission. Experimental results showed that the coated eye emitted visible light and that the intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

  13. The eyes of a tiny 'Orsten' crustacean - a compound eye at receptor level?

    Science.gov (United States)

    Schoenemann, Brigitte

    2013-01-14

    Among the oldest fossil crustaceans are those of the Late Cambrian (Furongian 499 ± 0.3-488.3 ± 1.7 Ma) of Västergötland, central Sweden and the lower Ordovician (Tremadocian 488.3 and 478.6 Ma) of the island of Őland. These are three-dimensionally preserved in nodules from the so called 'stinkstone' ('Orsten') limestone. 'Orsten'-like fossils represent tiny, often meiobenthic organsisms (Haug, Maas, & Waloszek, 2009) smaller than 2mm, which mainly were arthropods, especially crustaceans close to the stemline. As a result of phosphatisation, hairs, bristles and even cellular structures up to 0.3 μm are preserved (Walossek, 1993), especially compound eyes, as typical for all visually orientated crustaceans (Schoenemann et al., 2011). We show a miniscule prototype of a compound eye (∼40 μm) in a small crustacean, which lived almost half a billion years ago. The eye is close to but comfortably established above being limited in its resolving power by diffraction, but it is too small to be an apposition eye, normally regarded as the basal form of all compound eyes, as is found in bees, dragonflies, crustaceans and many other arthropods still living today. The facets of this compound eye are ∼8 μm in size, the surface structure indicates the relicts of a tiny lens covering each facet. In order to work functionally and to ensure that that diffraction and waveguide problems were avoided, it seems reasonable to suppose that the compound eye consisted of visual units, each with a single photoreceptor cell directly below a weak lens for capturing and slightly focusing the light. The entire unit has a diameter similar to that of a normal sensory cell as found in compound eyes. Thus, the early compound eye analysed here may be interpreted as a prototype representing the earliest stages of the evolution of crustacean compound eyes.

  14. Application of a novel superposition technique to the structure of an organophosphorus insecticide and an organometallic compound

    Energy Technology Data Exchange (ETDEWEB)

    Beckman, D.E.

    1979-01-01

    The structures of 0-0-dimethyl-0-(3,5,6-trichloro-2-pyridyl) phosphorothioate (Dowco 214) and dicarbonylbis(eta-cyclopentadienyl)-..mu..-carbonyl-..mu..-thiocarbonyldiiron have been solved by single crystal x-ray diffraction and use of a modified Patterson superposition technique that uses two multiple vectors to define a structural parallelogram. This method results in a simpler and more accurate shift vector position determination and a general improvement in map clarity. Dowco 214 crystallizes in the space group P/sub 1//sup -/ with a = 11.598(2) A, b = 13.619(3) A, c = 8.281(1) A, ..cap alpha.. = 94.65(1)/sup 0/, ..beta.. = 94.87(2)/sup 0/, ..gamma.. = 79.97(2)/sup 0/ and four molecules per cell (two per asymmetric unit). A CNDO II calculation was performed and partial charge densities assigned. The molecule contains distances between positively charged centers that correspond well to the reported anionic-esteratic distance (a possible reaction variable) in AChE. Additional reaction variables are discussed. Cp/sub 2/Fe/sub 2/(CO)/sub 3/CS crystallizes in the space group P2/sub 1//c with a = 14.508(8) A, b = 13.618(5) A, c = 15.193(7) A, ..beta.. = 110.50(6)/sup 0/ and eight molecules per unit cell (two per asymmetric unit). The compound contains both a carbonyl and thiocarbonyl bridge and ..pi..-bonded cyclopentadienyl rings that are cis to one another. The iron--iron bond length is intermediate to that of its carbonyl and thiocarbonyl analogs.

  15. Eyeless initiates the expression of both sine oculis and eyes absent during Drosophila compound eye development.

    Science.gov (United States)

    Halder, G; Callaerts, P; Flister, S; Walldorf, U; Kloter, U; Gehring, W J

    1998-06-01

    The Drosophila Pax-6 gene eyeless acts high up in the genetic hierarchy involved in compound eye development and can direct the formation of extra eyes in ectopic locations. Here we identify sine oculis and eyes absent as two mediators of the eye-inducing activity of eyeless. We show that eyeless induces and requires the expression of both genes independently during extra eye development. During normal eye development, eyeless is expressed earlier than and is required for the expression of sine oculis and eyes absent, but not vice versa. Based on the results presented here and those of others, we propose a model in which eyeless induces the initial expression of both sine oculis and eyes absent in the eye disc. sine oculis and eyes absent then appear to participate in a positive feedback loop that regulates the expression of all three genes. In contrast to the regulatory interactions that occur in the developing eye disc, we also show that in the embryonic head, sine oculis acts in parallel to eyeless and twin of eyeless, a second Pax-6 gene from Drosophila. Recent studies in vertebrate systems indicate that the epistatic relationships among the corresponding vertebrate homologs are very similar to those observed in Drosophila.

  16. Development of the compound eyes of dragonflies (Odonata). IV. Development of the adult compound eyes.

    Science.gov (United States)

    Sherk, T E

    1978-02-01

    The changes in the directions of view of marked larval ommatidia were observed after the emergence of the adult. Those ommatidia that had been present during the first larval instar had the most posterior directions of view in the adult visual field while the newest ommatidia that had not been functional for vision in the aquatic larva contributed to the anterior and dorsal foveas of the aerial adults. The changes in interommatidial angles at emergence are discussed. Contrary to the general trend for interommatidial angles between retained larval ommatidia to decrease at emergence, the interommatidial angles in the larval fovea of aeshnid visual predators increase at emergence. The modifications in an odonate compound eye at emergence are like an exaggeration of the modifications that occur at the moult from one larval instar to the next, except that the newest ommatidia do not have any compromises in their design for use in the aquatic vision of the larvae. This is in contrast to the ommatidia retained from the earliest larval instars which have to have the most compromises in their design so that they can be adapted for the visual requirements of every larval instar, as well as the adult. This is discussed in relation to the trend among advanced species of odonates to replace the larval ommatidia by an entirely new set of adult ommatidia.

  17. Endoscopic Application of a Compact Compound-Eye Camera

    Directory of Open Access Journals (Sweden)

    Keiichiro Kagawa

    2015-02-01

    Full Text Available A multi-functional compound-eye endoscope enabling multi-spectral imaging and variable field-of-view is presented, which is based on a compact compound-eye camera called TOMBO (thin observation module by bound optics. Narrow-band filters attached to some lenses provide snap-shot multi-band images. Fixed and movable mirrors are introduced to control the field of view, which realizes several observation modes such as three-dimensional shape measurement, wide field-of-view, and close-up observation.

  18. Endoscopic Application of a Compact Compound-Eye Camera

    OpenAIRE

    Keiichiro Kagawa; Shoji Kawahito

    2015-01-01

    A multi-functional compound-eye endoscope enabling multi-spectral imaging and variable field-of-view is presented, which is based on a compact compound-eye camera called TOMBO (thin observation module by bound optics). Narrow-band filters attached to some lenses provide snap-shot multi-band images. Fixed and movable mirrors are introduced to control the field of view, which realizes several observation modes such as three-dimensional shape measurement, wide field-of-view, and close-up observa...

  19. Compound eyes of insects and crustaceans: Some examples that show there is still a lot of work left to be done.

    Science.gov (United States)

    Meyer-Rochow, Victor Benno

    2015-03-01

    Similarities and differences between the 2 main kinds of compound eye (apposition and superposition) are briefly explained before several promising topics for research on compound eyes are being introduced. Research on the embryology and molecular control of the development of the insect clear-zone eye with superposition optics is one of the suggestions, because almost all of the developmental work on insect eyes in the past has focused on eyes with apposition optics. Age- and habitat-related ultrastructural studies of the retinal organization are another suggestion and the deer cad Lipoptena cervi, which has an aerial phase during which it is winged followed by a several months long parasitic phase during which it is wingless, is mentioned as a candidate species. Sexual dimorphism expressing itself in many species as a difference in eye structure and function provides another promising field for compound eye researchers and so is a focus on compound eye miniaturization in very small insects, especially those that are aquatic and belong to species, in which clear-zone eyes are diagnostic or are tiny insects that are not aquatic, but belong to taxa like the Diptera for instance, in which open rather than closed rhabdoms are the rule. Structures like interommatidial hairs and glands as well as corneal microridges are yet another field that could yield interesting results and in the past has received insufficient consideration. Finally, the dearth of information on distance vision and depth perception is mentioned and a plea is made to examine the photic environment inside the foam shelters of spittle bugs, chrysales of pupae and other structures shielding insects and crustaceans.

  20. Retinular fine structure in compound eyes of diurnal and nocturnal sphingid moths.

    Science.gov (United States)

    Eguchi, E

    1982-01-01

    Retinular fine structure has been compared in the superposition compound eyes of three sphingid moths, one nocturnal, Cechenena, and two diurnal, Cephonodes and Macroglossum. Cechenena and Cephonodes have tiered retinas with three kinds of retinular cells: two distal, six regular and one basal. The distal retinular cells in Cechenena are special in having a complex partially intracellular rhabdomere not present in Cephonodes. Macroglossum lacks the distal retinular cell. In Cephonodes a unique rhabdom type, formed by the six regular retinular cells in the middle region of the retinula, is divided into three separate longitudinal plates arranged closely parallel to one another. Their constituent microvilli are consequently all nearly unidirectional. The ratio of rhabdom volume to retinular cell volume in the two diurnal sphingids is 10-27%; this is about the same as that (25%) of skipper butterflies, but significantly smaller than in the nocturnal Cechenena (60%). In the diurnal sphingids retinular cell membranes show elongate meandering profiles with septate junctions between adjacent retinular cells. From the comparative fine structure of their eyes the diurnal sphingids and the skippers would appear to be phylogenetically closely related.

  1. Escaping compound eye ancestry: the evolution of single-chamber eyes in holometabolous larvae.

    Science.gov (United States)

    Buschbeck, Elke K

    2014-08-15

    Stemmata, the eyes of holometabolous insect larvae, have gained little attention, even though they exhibit remarkably different optical solutions, ranging from compound eyes with upright images, to sophisticated single-chamber eyes with inverted images. Such optical differences raise the question of how major transitions may have occurred. Stemmata evolved from compound eye ancestry, and optical differences are apparent even in some of the simplest systems that share strong cellular homology with adult ommatidia. The transition to sophisticated single-chamber eyes occurred many times independently, and in at least two different ways: through the fusion of many ommatidia [as in the sawfly (Hymenoptera)], and through the expansion of single ommatidia [as in tiger beetles (Coleoptera), antlions (Neuroptera) and dobsonflies (Megaloptera)]. Although ommatidia-like units frequently have multiple photoreceptor layers (tiers), sophisticated image-forming stemmata tend to only have one photoreceptor tier, presumably a consequence of the lens only being able to efficiently focus light on to one photoreceptor layer. An interesting exception is found in some diving beetles [Dytiscidae (Coleoptera)], in which two retinas receive sharp images from a bifocal lens. Taken together, stemmata represent a great model system to study an impressive set of optical solutions that evolved from a relatively simple ancestral organization.

  2. Characteristics of corneal lens chitin in dragonfly compound eyes.

    Science.gov (United States)

    Kaya, Murat; Sargin, Idris; Al-Jaf, Ivan; Erdogan, Sevil; Arslan, Gulsin

    2016-08-01

    Chitin in the compound eyes of arthropods serves as a part of the visual system. The quality of chitin in such highly specialised body parts deserves more detailed examination. Chitin in the corneal (ommatidial) lenses of dragonfly (Sympetrum fonscolombii) compound eyes was isolated by using the classical chemical method. The chitin content of the corneal lenses was determined to be quite high (20.3±0.85%). The FT-IR analysis showed that corneal lens chitin was in the α-form as found in all arthropod species where mechanical strength is required. The surface morphology analysis by scanning electron microscopy revealed that the outer part of corneal lenses consisted of long chitin fibrils with regular arrays of papillary structures while the smoother inner part had concentric lamellated chitin formation with shorter chitin nanofibrils. Chitinase enzymatic digestion studies, elemental analysis results and the degree of acetylation value showed the purity of chitin samples from corneal lens. The maximum degradation temperature value of the corneal lens chitin was observed at 369.2°C. X-ray analysis revealed that corneal lens chitin has high crystallinity index; 96.4%. Identification of chitin found in ommaditia of insect compound eyes can provide insights into insect vision and chitin-based optical material design studies.

  3. Interference of macroscopic superpositions

    CERN Document Server

    Vecchi, I

    2000-01-01

    We propose a simple experimental procedure based on the Elitzur-Vaidman scheme to implement a quantum nondemolition measurement testing the persistence of macroscopic superpositions. We conjecture that its implementation will reveal the persistence of superpositions of macroscopic objects in the absence of a direct act of observation.

  4. Postselected optomechanical superpositions

    CERN Document Server

    Pepper, Brian; Jeffrey, Evan; Simon, Christoph; Bouwmeester, Dirk

    2011-01-01

    We present a scheme for achieving macroscopic quantum superpositions in optomechanical systems by using single photon postselection. This method relieves many of the challenges associated with previous optical schemes for measuring macroscopic superpositions, and only requires the devices to be in the weak coupling regime. It requires only small improvements on currently achievable device parameters, and allows observation of decoherence on a timescale unconstrained by the system's optical decay time. Prospects for observing novel decoherence mechanisms are also discussed.

  5. Analyzing the reflections from single ommatidia in the butterfly compound eye with Voronoi diagrams

    NARCIS (Netherlands)

    Vanhoutte, KJA; Michielsen, KFL; Stavenga, DG

    2003-01-01

    This paper presents a robust method for the automated segmentation and quantitative measurement of reflections from single ommatidia in the butterfly compound eye. Digital pictures of the butterfly eye shine recorded with a digital camera are processed to yield binary images from which single facet

  6. Functional Morphology of the Divided Compound Eye of the Honeybee Drone (Apis mellifera)

    NARCIS (Netherlands)

    Menzel, J.G.; Wunderer, H.; Stavenga, D.G.

    1991-01-01

    Using different approaches, the functional morphology of the compound eye of the honeybee drone was examined. The drone exhibits an extended acute zone in the dorsal part of its eye. The following specializations were found here: enlarged facet diameters; smaller interommatidial angles; red-leaky sc

  7. Functional Morphology of the Divided Compound Eye of the Honeybee Drone (Apis mellifera)

    NARCIS (Netherlands)

    Menzel, J.G.; Wunderer, H.; Stavenga, D.G.

    1991-01-01

    Using different approaches, the functional morphology of the compound eye of the honeybee drone was examined. The drone exhibits an extended acute zone in the dorsal part of its eye. The following specializations were found here: enlarged facet diameters; smaller interommatidial angles; red-leaky sc

  8. Functional Morphology of the Divided Compound Eye of the Honeybee Drone (Apis mellifera)

    NARCIS (Netherlands)

    Menzel, J.G.; Wunderer, H.; Stavenga, D.G.

    1991-01-01

    Using different approaches, the functional morphology of the compound eye of the honeybee drone was examined. The drone exhibits an extended acute zone in the dorsal part of its eye. The following specializations were found here: enlarged facet diameters; smaller interommatidial angles; red-leaky

  9. Photoreceptor Redox State Monitored In Vivo by Transmission and Fluorescence Microspectrophotometry in Blowfly Compound Eyes

    NARCIS (Netherlands)

    Tinbergen, J.; Stavenga, D.G.

    1986-01-01

    The transmission and fluorescence of the compound eye of living, intact blowflies Calliphora erythrocephala, mutant chalky, were studied microspectrophotometrically. Transmission spectra were recorded under four conditions. The fly was either in the normal air environment or in a nitrogen

  10. ten-a overexpression causes abnormal pattern in the Drosophila compound eye

    Institute of Scientific and Technical Information of China (English)

    LERTLUK NGERNSIRI; NORA FASCETTI; SUPPALUK ROMRATANAPAN; STEFAN BAUMGARTNER

    2006-01-01

    Ten-a is one of the two Drosophila proteins that belong to the Ten M protein family. This protein is a type Ⅱ transmembrane protein and is expressed mainly in the embryonic CNS, in the larval eye imaginal disc and in the compound eye of the pupa. Here,we investigate the role of ten-a during development of the compound eye by using the Gal4/UAS system to induce ten-a overexpression in the developing eye. We found that overexpression of ten-a can perturb eye development during all stages examined. In an early stage, overexpression of ten-a in eye primordial cells caused small and rough eyes and interfered with photoreceptor cell recruitment, resulting in some ommatidia having fewer or extra photoreceptor cells. Conversely, ten-a overexpression during ommatidial formation caused severe eye defects due to absence of many cellular components. Interestingly,overexpression of ten-a in the late stage developing ommatidial cluster affected the number of pigment cells, caused cone cells proliferation in many ommatidia, and caused some photoreceptor cell defects. These results suggest that ten-a may be a novel gene required for normal eye morphogenesis.

  11. Acute vision in the giant Cambrian predator Anomalocaris and the origin of compound eyes.

    Science.gov (United States)

    Paterson, John R; García-Bellido, Diego C; Lee, Michael S Y; Brock, Glenn A; Jago, James B; Edgecombe, Gregory D

    2011-12-07

    Until recently, intricate details of the optical design of non-biomineralized arthropod eyes remained elusive in Cambrian Burgess-Shale-type deposits, despite exceptional preservation of soft-part anatomy in such Konservat-Lagerstätten. The structure and development of ommatidia in arthropod compound eyes support a single origin some time before the latest common ancestor of crown-group arthropods, but the appearance of compound eyes in the arthropod stem group has been poorly constrained in the absence of adequate fossils. Here we report 2-3-cm paired eyes from the early Cambrian (approximately 515 million years old) Emu Bay Shale of South Australia, assigned to the Cambrian apex predator Anomalocaris. Their preserved visual surfaces are composed of at least 16,000 hexagonally packed ommatidial lenses (in a single eye), rivalling the most acute compound eyes in modern arthropods. The specimens show two distinct taphonomic modes, preserved as iron oxide (after pyrite) and calcium phosphate, demonstrating that disparate styles of early diagenetic mineralization can replicate the same type of extracellular tissue (that is, cuticle) within a single Burgess-Shale-type deposit. These fossils also provide compelling evidence for the arthropod affinities of anomalocaridids, push the origin of compound eyes deeper down the arthropod stem lineage, and indicate that the compound eye evolved before such features as a hardened exoskeleton. The inferred acuity of the anomalocaridid eye is consistent with other evidence that these animals were highly mobile visual predators in the water column. The existence of large, macrophagous nektonic predators possessing sharp vision--such as Anomalocaris--within the early Cambrian ecosystem probably helped to accelerate the escalatory 'arms race' that began over half a billion years ago.

  12. Superpositions of probability distributions

    Science.gov (United States)

    Jizba, Petr; Kleinert, Hagen

    2008-09-01

    Probability distributions which can be obtained from superpositions of Gaussian distributions of different variances v=σ2 play a favored role in quantum theory and financial markets. Such superpositions need not necessarily obey the Chapman-Kolmogorov semigroup relation for Markovian processes because they may introduce memory effects. We derive the general form of the smearing distributions in v which do not destroy the semigroup property. The smearing technique has two immediate applications. It permits simplifying the system of Kramers-Moyal equations for smeared and unsmeared conditional probabilities, and can be conveniently implemented in the path integral calculus. In many cases, the superposition of path integrals can be evaluated much easier than the initial path integral. Three simple examples are presented, and it is shown how the technique is extended to quantum mechanics.

  13. Superpositions of probability distributions.

    Science.gov (United States)

    Jizba, Petr; Kleinert, Hagen

    2008-09-01

    Probability distributions which can be obtained from superpositions of Gaussian distributions of different variances v=sigma;{2} play a favored role in quantum theory and financial markets. Such superpositions need not necessarily obey the Chapman-Kolmogorov semigroup relation for Markovian processes because they may introduce memory effects. We derive the general form of the smearing distributions in v which do not destroy the semigroup property. The smearing technique has two immediate applications. It permits simplifying the system of Kramers-Moyal equations for smeared and unsmeared conditional probabilities, and can be conveniently implemented in the path integral calculus. In many cases, the superposition of path integrals can be evaluated much easier than the initial path integral. Three simple examples are presented, and it is shown how the technique is extended to quantum mechanics.

  14. Replication and characterization of the compound eye of a fruit fly for imaging purpose

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hefu [State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888, Dongnanhu Road, Changchun, Jilin (China); University of Chinese Academy of Sciences, Beijing 10039 (China); Gong, Xianwei; Ni, Qiliang; Zhao, Jingli; Zhang, Hongsheng; Wang, Taisheng [State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, No. 3888, Dongnanhu Road, Changchun, Jilin (China); Yu, Weixing, E-mail: yuwx@szu.edu.cn [Insititue of Micro and Nano Optics, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China)

    2014-10-06

    In this work, we report the replication and characterization of the compound eye of a fruit fly for imaging purpose. In the replication, soft lithography method was employed to replicate the compound eye of a fruit fly into a UV-curable polymer. The method was demonstrated to be effective and the compound eye is replicated into the polymer (NOA78) where each ommatidium has a diameter of about 30 μm and a sag height of about 7 μm. To characterize its optical property, the point spread function of the compound eye was tested and a NA of 0.386 has been obtained for the replicated polymeric ommatidium. Comparing with the NA of a real fruit fly ommatidium which was measured to be about 0.212, the replicated polymeric ommatidium has a much larger NA due to the refractive index of NOA78 is much higher than that of the material used to form the real fruit fly ommatidium. Furthermore, the replicated compound eye was used to image a photomask patterned with grating structures to test its imaging property. It is shown that the grating with a line width of 20 μm can be clearly imaged. The image of the grating formed by the replicated compound eye was shrunk by about 10 times and therefore a line width of about 2.2 μm in the image plane has been obtained, which is close to the diffraction limited resolution calculated through the measured NA. In summary, the replication method demonstrated is effective and the replicated compound eye has the great potential in optical imaging.

  15. Replication and characterization of the compound eye of a fruit fly for imaging purpose

    Science.gov (United States)

    Li, Hefu; Gong, Xianwei; Ni, Qiliang; Zhao, Jingli; Zhang, Hongsheng; Wang, Taisheng; Yu, Weixing

    2014-10-01

    In this work, we report the replication and characterization of the compound eye of a fruit fly for imaging purpose. In the replication, soft lithography method was employed to replicate the compound eye of a fruit fly into a UV-curable polymer. The method was demonstrated to be effective and the compound eye is replicated into the polymer (NOA78) where each ommatidium has a diameter of about 30 μm and a sag height of about 7 μm. To characterize its optical property, the point spread function of the compound eye was tested and a NA of 0.386 has been obtained for the replicated polymeric ommatidium. Comparing with the NA of a real fruit fly ommatidium which was measured to be about 0.212, the replicated polymeric ommatidium has a much larger NA due to the refractive index of NOA78 is much higher than that of the material used to form the real fruit fly ommatidium. Furthermore, the replicated compound eye was used to image a photomask patterned with grating structures to test its imaging property. It is shown that the grating with a line width of 20 μm can be clearly imaged. The image of the grating formed by the replicated compound eye was shrunk by about 10 times and therefore a line width of about 2.2 μm in the image plane has been obtained, which is close to the diffraction limited resolution calculated through the measured NA. In summary, the replication method demonstrated is effective and the replicated compound eye has the great potential in optical imaging.

  16. Exclusion of identification by negative superposition

    Directory of Open Access Journals (Sweden)

    Takač Šandor

    2012-01-01

    Full Text Available The paper represents the first report of negative superposition in our country. Photo of randomly selected young, living woman was superimposed on the previously discovered female skull. Computer program Adobe Photoshop 7.0 was used in work. Digitilized photographs of the skull and face, after uploaded to computer, were superimposed on each other and displayed on the monitor in order to assess their possible similarities or differences. Special attention was payed to matching the same anthropometrical points of the skull and face, as well as following their contours. The process of fitting the skull and the photograph is usually started by setting eyes in correct position relative to the orbits. In this case, lower jaw gonions go beyond the face contour and gnathion is highly placed. By positioning the chin, mouth and nose their correct anatomical position cannot be achieved. All the difficulties associated with the superposition were recorded, with special emphasis on critical evaluation of work results in a negative superposition. Negative superposition has greater probative value (exclusion of identification than positive (possible identification. 100% negative superposition is easily achieved, but 100% positive - almost never. 'Each skull is unique and viewed from different perspectives is always a new challenge'. From this point of view, identification can be negative or of high probability.

  17. Compound eye adaptations for diurnal and nocturnal lifestyle in the intertidal ant, Polyrhachis sokolova.

    Directory of Open Access Journals (Sweden)

    Ajay Narendra

    Full Text Available The Australian intertidal ant, Polyrhachis sokolova lives in mudflat habitats and nests at the base of mangroves. They are solitary foraging ants that rely on visual cues. The ants are active during low tides at both day and night and thus experience a wide range of light intensities. We here ask the extent to which the compound eyes of P. sokolova reflect the fact that they operate during both day and night. The ants have typical apposition compound eyes with 596 ommatidia per eye and an interommatidial angle of 6.0°. We find the ants have developed large lenses (33 µm in diameter and wide rhabdoms (5 µm in diameter to make their eyes highly sensitive to low light conditions. To be active at bright light conditions, the ants have developed an extreme pupillary mechanism during which the primary pigment cells constrict the crystalline cone to form a narrow tract of 0.5 µm wide and 16 µm long. This pupillary mechanism protects the photoreceptors from bright light, making the eyes less sensitive during the day. The dorsal rim area of their compound eye has specialised photoreceptors that could aid in detecting the orientation of the pattern of polarised skylight, which would assist the animals to determine compass directions required while navigating between nest and food sources.

  18. Bionic Mosaic Method of Panoramic Image Based on Compound Eye of Fly

    Institute of Scientific and Technical Information of China (English)

    Haipeng Chen; Xuanjing Shen; Xiaofei Li; Yushan Jin

    2011-01-01

    To satisfy the requirements of real-time and high quality mosaics,a bionic compound eye visual system was designed by simulating the visual mechanism of a fly compound eye.Several CCD cameras were used in this system to imitate the small eyes of a compound eye.Based on the optical analysis of this system,a direct panoramic image mosaic algorithm was proposed.Several sub-images were collected by the bionic compound eye visual system,and then the system obtained the overlapping proportions of these sub-images and cut the overlap sections of the neighboring images.Thus,a panoramic image with a large field of view was directly mosaicked,which expanded the field and guaranteed the high resolution.The experimental results show that the time consumed by the direct mosaic algorithm is only 2.2% of that by the traditional image mosaic algorithm while guaranteeing mosaic quality.Furthermore,the proposed method effectively solved the problem of misalignment of the mosaic image and eliminated mosaic cracks as a result of the illumination factor and other factors.This method has better real-time properties compared to other methods.

  19. Opsin evolution and expression in Arthropod compound Eyes and Ocelli: Insights from the cricket Gryllus bimaculatus

    Directory of Open Access Journals (Sweden)

    Henze Miriam J

    2012-08-01

    Full Text Available Abstract Background Opsins are key proteins in animal photoreception. Together with a light-sensitive group, the chromophore, they form visual pigments which initiate the visual transduction cascade when photoactivated. The spectral absorption properties of visual pigments are mainly determined by their opsins, and thus opsins are crucial for understanding the adaptations of animal eyes. Studies on the phylogeny and expression pattern of opsins have received considerable attention, but our knowledge about insect visual opsins is still limited. Up to now, researchers have focused on holometabolous insects, while general conclusions require sampling from a broader range of taxa. We have therefore investigated visual opsins in the ocelli and compound eyes of the two-spotted cricket Gryllus bimaculatus, a hemimetabolous insect. Results Phylogenetic analyses place all identified cricket sequences within the three main visual opsin clades of insects. We assign three of these opsins to visual pigments found in the compound eyes with peak absorbances in the green (515 nm, blue (445 nm and UV (332 nm spectral range. Their expression pattern divides the retina into distinct regions: (1 the polarization-sensitive dorsal rim area with blue- and UV-opsin, (2 a newly-discovered ventral band of ommatidia with blue- and green-opsin and (3 the remainder of the compound eye with UV- and green-opsin. In addition, we provide evidence for two ocellar photopigments with peak absorbances in the green (511 nm and UV (350 nm spectral range, and with opsins that differ from those expressed in the compound eyes. Conclusions Our data show that cricket eyes are spectrally more specialized than has previously been assumed, suggesting that similar adaptations in other insect species might have been overlooked. The arrangement of spectral receptor types within some ommatidia of the cricket compound eyes differs from the generally accepted pattern found in holometabolous insect

  20. Analyzing the reflections from single ommatidia in the butterfly compound eye with Voronoi diagrams.

    Science.gov (United States)

    Vanhoutte, Kurt J A; Michielsen, Kristel F L; Stavenga, Doekele G

    2003-12-30

    This paper presents a robust method for the automated segmentation and quantitative measurement of reflections from single ommatidia in the butterfly compound eye. Digital pictures of the butterfly eye shine recorded with a digital camera are processed to yield binary images from which single facet centers can be extracted using a morphological image analysis procedure. The location of the facet centers is corrected by fitting in-line facet centers to a second-order polynomial. Based on the new centers a Voronoi diagram is constructed. In the case of the eye shine images, the Voronoi diagram defines a hexagonal lattice that overlaps with the original facet borders, allowing instantaneous quantification of the reflections from single ommatidia. We provide two typical examples to demonstrate that the developed technique may be a powerful tool to characterize in vivo the heterogeneity of butterfly eyes and to study the dynamic control of the light flux by the pupil mechanism.

  1. Ommatidial heterogeneity in the compound eye of the male small white butterfly, Pieris rapae crucivora

    NARCIS (Netherlands)

    Qiu, XD; Vanhoutte, KAJ; Stavenga, DG; Arikawa, K; Qiu, Xudong

    The ommatidia in the ventral two-thirds of the compound eye of male Pieris rapae crucivora are not uniform. Each ommatidium contains nine photoreceptor cells. Four cells (R1-4) form the distal two-thirds of the rhabdom, four cells (R5-8) approximately occupy the proximal one-third of the rhabdom,

  2. Research on the image fusion and target extraction based on bionic compound eye system

    Science.gov (United States)

    Zhang, Shaowei; Hao, Qun; Song, Yong; Wang, Zihan; Zhang, Kaiyu; Zhang, Shiyu

    2015-08-01

    People attach more and more importance to bionic compound eye due to its advantages such as small volume, large field of view and sensitivity to high-speed moving objects. Small field of view and large volume are the disadvantages of traditional image sensor and in order to avoid these defects, this paper intends to build a set of compound eye system based on insect compound eye structure and visual processing mechanism. In the center of this system is the primary sensor which has high resolution ratio. The primary sensor is surrounded by the other six sensors which have low resolution ratio. Based on this system, this paper will study the target image fusion and extraction method by using plane compound eye structure. This paper designs a control module which can combine the distinguishing features of high resolution image with local features of low resolution image so as to conduct target detection, recognition and location. Compared with traditional ways, the way of high resolution in the center and low resolution around makes this system own the advantages of high resolution and large field of view and enables the system to detect the object quickly and recognize the object accurately.

  3. Ultrastructure and Morphology of Compound Eyes of the Scorpionfly Panorpa dubia (Insecta: Mecoptera: Panorpidae.

    Directory of Open Access Journals (Sweden)

    Qing-Xiao Chen

    Full Text Available Mecoptera are unique in holometabolous insects in that their larvae have compound eyes. In the present study the cellular organisation and morphology of the compound eyes of adult individuals of the scorpionfly Panorpa dubia in Mecoptera were investigated by light, scanning electron, and transmission electron microscopy. The results showed that the compound eyes of adult P. dubia are of the apposition type, each eye comprising more than 1200 ommatidia. The ommatidium consists of a cornea, a crystalline cone made up of four cone cells, eight photoreceptors, two primary pigment cells, and 18 secondary pigment cells. The adult ommatidium has a fused rhabdom with eight photoreceptors. Seven photoreceptors extend from the proximal end of the crystalline cone to the basal matrix, whereas the eighth photoreceptor is shorter, extending from the middle level of the photoreceptor cluster to the basal matrix. The fused rhabdom is composed of the rhabdomeres of different photoreceptors at different levels. The adult ommatidia have the same cellular components as the larval ommatidia, but the tiering scheme is different.

  4. Superposition Enhanced Nested Sampling

    Directory of Open Access Journals (Sweden)

    Stefano Martiniani

    2014-08-01

    Full Text Available The theoretical analysis of many problems in physics, astronomy, and applied mathematics requires an efficient numerical exploration of multimodal parameter spaces that exhibit broken ergodicity. Monte Carlo methods are widely used to deal with these classes of problems, but such simulations suffer from a ubiquitous sampling problem: The probability of sampling a particular state is proportional to its entropic weight. Devising an algorithm capable of sampling efficiently the full phase space is a long-standing problem. Here, we report a new hybrid method for the exploration of multimodal parameter spaces exhibiting broken ergodicity. Superposition enhanced nested sampling combines the strengths of global optimization with the unbiased or athermal sampling of nested sampling, greatly enhancing its efficiency with no additional parameters. We report extensive tests of this new approach for atomic clusters that are known to have energy landscapes for which conventional sampling schemes suffer from broken ergodicity. We also introduce a novel parallelization algorithm for nested sampling.

  5. A bio-inspired apposition compound eye machine vision sensor system.

    Science.gov (United States)

    Davis, J D; Barrett, S F; Wright, C H G; Wilcox, M

    2009-12-01

    The Wyoming Information, Signal Processing, and Robotics Laboratory is developing a wide variety of bio-inspired vision sensors. We are interested in exploring the vision system of various insects and adapting some of their features toward the development of specialized vision sensors. We do not attempt to supplant traditional digital imaging techniques but rather develop sensor systems tailor made for the application at hand. We envision that many applications may require a hybrid approach using conventional digital imaging techniques enhanced with bio-inspired analogue sensors. In this specific project, we investigated the apposition compound eye and its characteristics commonly found in diurnal insects and certain species of arthropods. We developed and characterized an array of apposition compound eye-type sensors and tested them on an autonomous robotic vehicle. The robot exhibits the ability to follow a pre-defined target and avoid specified obstacles using a simple control algorithm.

  6. A bio-inspired apposition compound eye machine vision sensor system

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J D [Applied Research Laboratories, University of Texas, 10000 Burnet Rd, Austin, TX 78757 (United States); Barrett, S F; Wright, C H G [Electrical and Computer Engineering, University of Wyoming, Dept 3295 1000 E. University Ave, Laramie, WY 82071 (United States); Wilcox, M, E-mail: steveb@uwyo.ed [Department of Biology, United States Air Force Academy, CO 80840 (United States)

    2009-12-15

    The Wyoming Information, Signal Processing, and Robotics Laboratory is developing a wide variety of bio-inspired vision sensors. We are interested in exploring the vision system of various insects and adapting some of their features toward the development of specialized vision sensors. We do not attempt to supplant traditional digital imaging techniques but rather develop sensor systems tailor made for the application at hand. We envision that many applications may require a hybrid approach using conventional digital imaging techniques enhanced with bio-inspired analogue sensors. In this specific project, we investigated the apposition compound eye and its characteristics commonly found in diurnal insects and certain species of arthropods. We developed and characterized an array of apposition compound eye-type sensors and tested them on an autonomous robotic vehicle. The robot exhibits the ability to follow a pre-defined target and avoid specified obstacles using a simple control algorithm.

  7. Sensory eye irritation in humans exposed to mixtures of volatile organic compounds

    DEFF Research Database (Denmark)

    Hempel-Jørgensen, Anne Hempel; Kjærgaard, Søren K.; Mølhave, Lars;

    1999-01-01

    Eight subjects participated in a controlled eyes-only exposure study of human sensory irritation in ocular mucosal tissue. The authors investigated dose-response properties and the additive effects of three mixtures of volatile organic compounds. The dose-response relationships for these mixtures...... to as simple agonism. Finally, the authors addressed the comparability of two methods to measure sensory irritation intensity (visual analogue scale and a comparative scale). The results indicated that the two rating methods produced highly comparable results....

  8. A Novel System for Moving Object Detection Using Bionic Compound Eyes

    Institute of Scientific and Technical Information of China (English)

    Huabo Sun; Haimeng Zhao; Peter Mooney; Hongying Zhao; Daping Liu; Lei Yan

    2011-01-01

    Conventional moving target detection focuses on algorithms to improve detection efficiency. These algorithms pay less attention to the image acquisition means, and usually solve specific problems. This often results in poor flexibility and reusability. Insect compound eyes offer unique advantages for moving target detection and these advantages have attracted the attention of many researchers in recent years. In this paper we proposed a new system for moving target detection. We used the detection mechanism of insect compound eyes for the simulation of the characteristics of structure, control, and function. We discussed the design scheme of the system, the development of the bionic control circuit, and introduced the proposed mathematical model of bionic compound eyes for data acquisition and object detection. After this the integrated system was described and discussed. Our paper presents a novel approach for moving target detection. This approach effectively tackles some of the well-known problems in the field of view, resolution, and real-time processing problems in moving target detection.

  9. Network class superposition analyses.

    Directory of Open Access Journals (Sweden)

    Carl A B Pearson

    Full Text Available Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., ≈ 10(30 for the yeast cell cycle process, considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix T, which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for T derived from boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying T to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with T. We show how to generate Derrida plots based on T. We show that T-based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on T. We motivate all of these results in terms of a popular molecular biology boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for T, for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses.

  10. Quantum superpositions of crystalline structures

    CERN Document Server

    Baltrusch, Jens D; De Chiara, Gabriele; Calarco, Tommaso; Morigi, Giovanna

    2011-01-01

    A procedure is discussed for creating coherent superpositions of motional states of ion strings. The motional states are across the structural transition linear-zigzag, and their coherent superposition is achieved by means of spin-dependent forces, such that a coherent superposition of the electronic states of one ion evolves into an entangled state between the chain's internal and external degrees of freedom. It is shown that the creation of such an entangled state can be revealed by performing Ramsey interferometry with one ion of the chain.

  11. Moonlight detection by Drosophila's endogenous clock depends on multiple photopigments in the compound eyes.

    Science.gov (United States)

    Schlichting, Matthias; Grebler, Rudi; Peschel, Nicolai; Yoshii, Taishi; Helfrich-Förster, Charlotte

    2014-04-01

    Many organisms change their activity on moonlit nights. Even the fruit fly Drosophila melanogaster responds to moonlight with a shift of activity into the night, at least under laboratory conditions. The compound eyes have been shown to be essential for the perception of moonlight, but it is unknown which of the 5 rhodopsins in the eyes are responsible for the observed moonlight effects. Here, we show that the outer (R1-R6) and inner (R7 and R8) photoreceptor cells in a fly's ommatidium interact in a complex manner to provoke the moonlight effects on locomotor activity. The shift of the evening activity peak into the night depends on several rhodopsins in the inner and outer photoreceptor cells. The increase in relative nocturnal activity in response to moonlight is mainly mediated by the rhodopsin 6-expressing inner photoreceptor cell R8 together with the rhodopsin 1-expressing outer receptor cells (R1-R6), whereas just rhodopsin 1 of R1 to R6 seems necessary for increasing nocturnal activity in response to increasing daylight intensity.

  12. Design and fabrication of a multi-focusing artificial compound eyes with negative meniscus substrate

    Science.gov (United States)

    Luo, Jiasai; Guo, Yongcai; Wang, Xin; Fan, Fenglian

    2017-04-01

    Miniaturized artificial compound eyes with a large field of view (FOV) have potential application in the area of micro-optical-electro-mechanical-system (MOEMS). A new non-uniform microlens array (MLA) on a negative meniscus substrate, fabricated by the melting photoresist method, was proposed in this paper. The multi-focusing MLA reduced the defocus effectively, which was caused by the uniform array on a spherical substrate. Moreover, like most ommatidia in compound eyes, each microlens of the multi-focusing MLA was arranged in one of the eleven concentric circles. In order to match with the multi-focusing MLA and avoid the total reflection, the negative meniscus substrate was fabricated by a homebuilt mold with a micro-hole array and polydimethylsiloxane coelomic compartment attached. The coelomic compartment is capable of offering an excellent injection environment without bubbles and impurities. Due to the direct 3D implementation of the MLA, rich available materials can be used by this method without substrate reshaping. As the molding material, the ultraviolet curing adhesive NOA81 can be cured within ten few seconds under ultraviolet which relieve intensive labor and protect the stereolithography apparatus effectively. The experimental results show that this new MLA has a better imaging performance, higher light usage efficiency and larger FOV because of the negative meniscus and multi-focusing MLA. Moreover, due to the homebuilt mold, more accurate geometrical parameters and shorter processing cycle were realized. Accordingly, together with an appropriate hardware, this MLA has diverse potential applications in medical imaging, military and machine vision.

  13. Optimization and validation of an existing, surgical and robust dry eye rat model for the evaluation of therapeutic compounds.

    Science.gov (United States)

    Joossen, Cedric; Lanckacker, Ellen; Zakaria, Nadia; Koppen, Carina; Joossens, Jurgen; Cools, Nathalie; De Meester, Ingrid; Lambeir, Anne-Marie; Delputte, Peter; Maes, Louis; Cos, Paul

    2016-05-01

    The aim of this research was to optimize and validate an animal model for dry eye, adopting clinically relevant evaluation parameters. Dry eye was induced in female Wistar rats by surgical removal of the exorbital lacrimal gland. The clinical manifestations of dry eye were evaluated by tear volume measurements, corneal fluorescein staining, cytokine measurements in tear fluid, MMP-9 mRNA expression and CD3(+) cell infiltration in the conjunctiva. The animal model was validated by treatment with Restasis(®) (4 weeks) and commercial dexamethasone eye drops (2 weeks). Removal of the exorbital lacrimal gland resulted in 50% decrease in tear volume and a gradual increase in corneal fluorescein staining. Elevated levels of TNF-α and IL-1α have been registered in tear fluid together with an increase in CD3(+) cells in the palpebral conjunctiva when compared to control animals. Additionally, an increase in MMP-9 mRNA expression was recorded in conjunctival tissue. Reference treatment with Restasis(®) and dexamethasone eye drops had a positive effect on all evaluation parameters, except on tear volume. This rat dry eye model was validated extensively and judged appropriate for the evaluation of novel compounds and therapeutic preparations for dry eye disease.

  14. Adaptations for nocturnal vision in insect apposition eyes.

    Science.gov (United States)

    Greiner, Birgit

    2006-01-01

    Due to our own preference for bright light, we tend to forget that many insects are active in very dim light. Nocturnal insects possess in general superposition compound eyes. This eye design is truly optimized for dim light as photons can be gathered through large apertures comprised of hundreds of lenses. In apposition eyes, on the other hand, the aperture consists of a single lens resulting in a poor photon catch and unreliable vision in dim light. Apposition eyes are therefore typically found in day-active insects. Some nocturnal insects have nevertheless managed the transition to a strictly nocturnal lifestyle while retaining their highly unsuitable apposition eye design. Large lenses and wide photoreceptors enhance the sensitivity of nocturnal apposition eyes. However, as the gain of these optical adaptations is limited and not sufficient for vision in dim light, additional neural adaptations in the form of spatial and temporal summation are necessary.

  15. Nonlinear dynamics by mode superposition

    Energy Technology Data Exchange (ETDEWEB)

    Nickell, R.E.

    1976-01-01

    A mode superposition technique for approximately solving nonlinear initial-boundary-value problems of structural dynamics is discussed, and results for examples involving large deformation are compared to those obtained with implicit direct integration methods such as the Newmark generalized acceleration and Houbolt backward-difference operators. The initial natural frequencies and mode shapes are found by inverse power iteration with the trial vectors for successively higher modes being swept by Gram-Schmidt orthonormalization at each iteration. The subsequent modal spectrum for nonlinear states is based upon the tangent stiffness of the structure and is calculated by a subspace iteration procedure that involves matrix multiplication only, using the most recently computed spectrum as an initial estimate. Then, a precise time integration algorithm that has no artificial damping or phase velocity error for linear problems is applied to the uncoupled modal equations of motion. Squared-frequency extrapolation is examined for nonlinear problems as a means by which these qualities of accuracy and precision can be maintained when the state of the system (and, thus, the modal spectrum) is changing rapidly. The results indicate that a number of important advantages accrue to nonlinear mode superposition: (a) there is no significant difference in total solution time between mode superposition and implicit direct integration analyses for problems having narrow matric half-bandwidth (in fact, as bandwidth increases, mode superposition becomes more economical), (b) solution accuracy is under better control since the analyst has ready access to modal participation factors and the ratios of time step size to modal period, and (c) physical understanding of nonlinear dynamic response is improved since the analyst is able to observe the changes in the modal spectrum as deformation proceeds.

  16. Cryptochrome is present in the compound eyes and a subset of Drosophila's clock neurons.

    Science.gov (United States)

    Yoshii, Taishi; Todo, Takeshi; Wülbeck, Corinna; Stanewsky, Ralf; Helfrich-Förster, Charlotte

    2008-06-20

    Cryptochrome (CRY) is intimately associated with the circadian clock of many organisms. In the fruit fly Drosophila melanogaster, CRY seems to be involved in photoreception as well as in the core clockwork. In spite of the critical role of CRY for the clock of Drosophila, it was not quite clear whether CRY is expressed in every clock cell. With the help of a new antibody and a mutant that lacks CRY, we show here that CRY is expressed in specific subsets of Drosophila's pacemaker neurons and in the photoreceptor cells of the compound eyes. In the pacemaker neurons, CRY levels and kinetics under light-dark cycles are quite different from each other. High-amplitude oscillations are observed in only three groups of clock neurons, suggesting that these three groups are strongly receptive to light. The different CRY kinetics may account for phase differences in oscillations of the clock proteins observed in these three groups in earlier studies. The molecular clock of the neurons that contain lower CRY levels or are completely CRY negative can still be synchronized by light, probably via intercellular communication with the CRY-positive neurons as well as via external photoreceptors.

  17. Hardware architecture and cutting-edge assembly process of a tiny curved compound eye.

    Science.gov (United States)

    Viollet, Stéphane; Godiot, Stéphanie; Leitel, Robert; Buss, Wolfgang; Breugnon, Patrick; Menouni, Mohsine; Juston, Raphaël; Expert, Fabien; Colonnier, Fabien; L'Eplattenier, Géraud; Brückner, Andreas; Kraze, Felix; Mallot, Hanspeter; Franceschini, Nicolas; Pericet-Camara, Ramon; Ruffier, Franck; Floreano, Dario

    2014-11-17

    The demand for bendable sensors increases constantly in the challenging field of soft and micro-scale robotics. We present here, in more detail, the flexible, functional, insect-inspired curved artificial compound eye (CurvACE) that was previously introduced in the Proceedings of the National Academy of Sciences (PNAS, 2013). This cylindrically-bent sensor with a large panoramic field-of-view of 180° × 60° composed of 630 artificial ommatidia weighs only 1.75 g, is extremely compact and power-lean (0.9 W), while it achieves unique visual motion sensing performance (1950 frames per second) in a five-decade range of illuminance. In particular, this paper details the innovative Very Large Scale Integration (VLSI) sensing layout, the accurate assembly fabrication process, the innovative, new fast read-out interface, as well as the auto-adaptive dynamic response of the CurvACE sensor. Starting from photodetectors and microoptics on wafer substrates and flexible printed circuit board, the complete assembly of CurvACE was performed in a planar configuration, ensuring high alignment accuracy and compatibility with state-of-the art assembling processes. The characteristics of the photodetector of one artificial ommatidium have been assessed in terms of their dynamic response to light steps. We also characterized the local auto-adaptability of CurvACE photodetectors in response to large illuminance changes: this feature will certainly be of great interest for future applications in real indoor and outdoor environments.

  18. Hardware Architecture and Cutting-Edge Assembly Process of a Tiny Curved Compound Eye

    Directory of Open Access Journals (Sweden)

    Stéphane Viollet

    2014-11-01

    Full Text Available The demand for bendable sensors increases constantly in the challenging field of soft and micro-scale robotics. We present here, in more detail, the flexible, functional, insect-inspired curved artificial compound eye (CurvACE that was previously introduced in the Proceedings of the National Academy of Sciences (PNAS, 2013. This cylindrically-bent sensor with a large panoramic field-of-view of \\(180^\\circ\\ \\(\\times\\ \\(60^\\circ\\composed of 630 artificial ommatidia weighs only 1.75 g, is extremely compact and power-lean (0.9 W, while it achieves unique visual motion sensing performance (1950 frames per second in a five-decade range of illuminance. In particular, this paper details the innovative Very Large Scale Integration (VLSI sensing layout, the accurate assembly fabrication process, the innovative, new fast read-out interface, as well as the auto-adaptive dynamic response of the CurvACE sensor. Starting from photodetectors and microoptics on wafer substrates and flexible printed circuit board, the complete assembly of CurvACE was performed in a planar configuration, ensuring high alignment accuracy and compatibility with state-of-the art assembling processes. The characteristics of the photodetector of one artificial ommatidium have been assessed in terms of their dynamic response to light steps. We also characterized the local auto-adaptability of CurvACE photodetectors in response to large illuminance changes: this feature will certainly be of great interest for future applications in real indoor and outdoor environments.

  19. Self-adaptive image reconstruction inspired by insect compound eye mechanism.

    Science.gov (United States)

    Zhang, Jiahua; Shi, Aiye; Wang, Xin; Bian, Linjie; Huang, Fengchen; Xu, Lizhong

    2012-01-01

    Inspired by the mechanism of imaging and adaptation to luminosity in insect compound eyes (ICE), we propose an ICE-based adaptive reconstruction method (ARM-ICE), which can adjust the sampling vision field of image according to the environment light intensity. The target scene can be compressive, sampled independently with multichannel through ARM-ICE. Meanwhile, ARM-ICE can regulate the visual field of sampling to control imaging according to the environment light intensity. Based on the compressed sensing joint sparse model (JSM-1), we establish an information processing system of ARM-ICE. The simulation of a four-channel ARM-ICE system shows that the new method improves the peak signal-to-noise ratio (PSNR) and resolution of the reconstructed target scene under two different cases of light intensity. Furthermore, there is no distinct block effect in the result, and the edge of the reconstructed image is smoother than that obtained by the other two reconstruction methods in this work.

  20. Self-Adaptive Image Reconstruction Inspired by Insect Compound Eye Mechanism

    Directory of Open Access Journals (Sweden)

    Jiahua Zhang

    2012-01-01

    Full Text Available Inspired by the mechanism of imaging and adaptation to luminosity in insect compound eyes (ICE, we propose an ICE-based adaptive reconstruction method (ARM-ICE, which can adjust the sampling vision field of image according to the environment light intensity. The target scene can be compressive, sampled independently with multichannel through ARM-ICE. Meanwhile, ARM-ICE can regulate the visual field of sampling to control imaging according to the environment light intensity. Based on the compressed sensing joint sparse model (JSM-1, we establish an information processing system of ARM-ICE. The simulation of a four-channel ARM-ICE system shows that the new method improves the peak signal-to-noise ratio (PSNR and resolution of the reconstructed target scene under two different cases of light intensity. Furthermore, there is no distinct block effect in the result, and the edge of the reconstructed image is smoother than that obtained by the other two reconstruction methods in this work.

  1. Deep-focus compound-eye camera with polarization filters for 3D endoscopes

    Science.gov (United States)

    Kagawa, Keiichiro; Tanaka, Eiji; Yamada, Kenji; Kawahito, Shoji; Tanida, Jun

    2012-03-01

    A deep-focus three-dimensional endoscope based on a compact compound-eye camera called TOMBO (thin observation module by bound optics) with polarization filters and polarized illuminations is presented. TOMBO is a very compact multi-camera system, which is composed of a single image sensor, a lens array, and a crosstalk barrier. Features of TOMBO are compactness of the camera system, and additional functionality achieved by attaching optical filters to lenses. In this paper, to enhance surface or deep structures of biological tissues selectively, polarization filters, which are parallel and vertical to the polarized illumination, respectively, are attached to a part of lenses. To achieve extended depth of focus, a wavefront coding (WFC) technique based on the spherical aberration is introduced. A prototype TOMBO with 3x3 lenses and a 2.2-μm-pixel color CMOS image sensor was fabricated. Depth estimation and superresolution with the WFC technique are demonstrated. Enhancement of surface or deep structures is also verified theoretically and experimentally.

  2. Superposition Attacks on Cryptographic Protocols

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Funder, Jakob Løvstad; Nielsen, Jesper Buus

    2011-01-01

    Attacks on classical cryptographic protocols are usually modeled by allowing an adversary to ask queries from an oracle. Security is then defined by requiring that as long as the queries satisfy some constraint, there is some problem the adversary cannot solve, such as compute a certain piece...... of information. In this paper, we introduce a fundamentally new model of quantum attacks on classical cryptographic protocols, where the adversary is allowed to ask several classical queries in quantum superposition. This is a strictly stronger attack than the standard one, and we consider the security...

  3. Superposition on a multicomputer system.

    Science.gov (United States)

    Murray, D C; Hoban, P W; Round, W H; Graham, I D; Metcalfe, P E

    1991-01-01

    Superposition (convolution using a noninvariant kernel) has been shown to be a highly promising technique for use in calculating dose distributions in radiotherapy treatment planning. However, one major difficulty that currently prevents use in routine planning is the computational effort required to perform the calculation in three dimensions. To help solve this problem the superposition technique has been implemented on a parallel processor multicomputer in order to examine the performance characteristics of such a system. Up to eight elements have been connected in a pipeline (linear array), and tree networks of three and seven processors have also been constructed (using INMOS T800 transputers). The significant results obtained with these networks are: (1) Both topologies provide near-linear speedup with increasing processor number (8 processors provide 7.81 times the computing power of a single processor when using an optimal communication packet size); (2) increasing communication packet size from 1 voxel to an optimum of approximately 40 voxels significantly reduces communication overhead per processor. Overhead per processor for a 7-element linear array is 6.9% when using 1-voxel packets, but only 1.8% when using 40-voxel packets; (3) the topology of the network has some effect on communication overhead: Arranging 7 processors in a 1-2-4 binary tree reduces overhead to 80.1% of that encountered using a 7-element linear array (with packet size of 1 voxel).

  4. Spreading of hemiretinal projections in the ipsilateral tectum following unilateral enucleation: a study of optic nerve regeneration in Xenopus with one compound eye.

    Science.gov (United States)

    Straznicky, C; Tay, D

    1981-02-01

    Right compound eyes were formed in Xenopus embryos at stages 32-33 by the fusion of two nasal (NN), two ventral (VV) or two temporal (TT) halves. Shortly after metamorphosis the optic nerve from the compound eye was sectioned and the left intact eye removed. The retinotectal projections from the compound eye to the contralateral and ipsilateral tecta were studied by [3H]proline autoradiography and electrophysiological mapping between 6 weeks and 5 months after the postmetamorphic surgery. The results showed that NN and VV eyes projected to the entire extent of both tecta. In contrast, optic fibre projection from TT eyes, although more extensive than the normal temporal hemiretinal projection, failed to cover the caudomedial portion of the tecta. The visuotectal projections in all three combinations corresponded to typical reduplicated maps to be expected from such compound eyes, where each of the hemiretinae projected across the contralateral and ipsilateral tecta in an overlapping fashion. The rapid expansion of the hemiretinal projections of the compound eyes in the ipsilateral tectum following the removal of the resident optic fibre projection suggests that tectal markers may be carried and deployed by the incoming optic fibres themselves.

  5. Creating a Superposition of Unknown Quantum States.

    Science.gov (United States)

    Oszmaniec, Michał; Grudka, Andrzej; Horodecki, Michał; Wójcik, Antoni

    2016-03-18

    The superposition principle is one of the landmarks of quantum mechanics. The importance of quantum superpositions provokes questions about the limitations that quantum mechanics itself imposes on the possibility of their generation. In this work, we systematically study the problem of the creation of superpositions of unknown quantum states. First, we prove a no-go theorem that forbids the existence of a universal probabilistic quantum protocol producing a superposition of two unknown quantum states. Second, we provide an explicit probabilistic protocol generating a superposition of two unknown states, each having a fixed overlap with the known referential pure state. The protocol can be applied to generate coherent superposition of results of independent runs of subroutines in a quantum computer. Moreover, in the context of quantum optics it can be used to efficiently generate highly nonclassical states or non-Gaussian states.

  6. Sex and caste-specific variation in compound eye morphology of five honeybee species.

    Directory of Open Access Journals (Sweden)

    Martin Streinzer

    Full Text Available Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana. In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the

  7. Sex and caste-specific variation in compound eye morphology of five honeybee species.

    Science.gov (United States)

    Streinzer, Martin; Brockmann, Axel; Nagaraja, Narayanappa; Spaethe, Johannes

    2013-01-01

    Ranging from dwarfs to giants, the species of honeybees show remarkable differences in body size that have placed evolutionary constrains on the size of sensory organs and the brain. Colonies comprise three adult phenotypes, drones and two female castes, the reproductive queen and sterile workers. The phenotypes differ with respect to tasks and thus selection pressures which additionally constrain the shape of sensory systems. In a first step to explore the variability and interaction between species size-limitations and sex and caste-specific selection pressures in sensory and neural structures in honeybees, we compared eye size, ommatidia number and distribution of facet lens diameters in drones, queens and workers of five species (Apis andreniformis, A. florea, A. dorsata, A. mellifera, A. cerana). In these species, male and female eyes show a consistent sex-specific organization with respect to eye size and regional specialization of facet diameters. Drones possess distinctly enlarged eyes with large dorsal facets. Aside from these general patterns, we found signs of unique adaptations in eyes of A. florea and A. dorsata drones. In both species, drone eyes are disproportionately enlarged. In A. dorsata the increased eye size results from enlarged facets, a likely adaptation to crepuscular mating flights. In contrast, the relative enlargement of A. florea drone eyes results from an increase in ommatidia number, suggesting strong selection for high spatial resolution. Comparison of eye morphology and published mating flight times indicates a correlation between overall light sensitivity and species-specific mating flight times. The correlation suggests an important role of ambient light intensities in the regulation of species-specific mating flight times and the evolution of the visual system. Our study further deepens insights into visual adaptations within the genus Apis and opens up future perspectives for research to better understand the timing mechanisms

  8. The expression of three opsin genes from the compound eye of Helicoverpa armigera (Lepidoptera: Noctuidae) is regulated by a circadian clock, light conditions and nutritional status

    National Research Council Canada - National Science Library

    Yan, Shuo; Zhu, Jialin; Zhu, Weilong; Zhang, Xinfang; Li, Zhen; Liu, Xiaoxia; Zhang, Qingwen

    2014-01-01

    .... In this study, we cloned the ultraviolet (UV), blue (BL) and long-wavelength-sensitive (LW) opsin genes from the compound eye of the cotton bollworm and then measured their mRNA levels using quantitative real-time PCR...

  9. Diurnal and circadian rhythm in compound eye of cricket (Gryllus bimaculatus): changes in structure and photon capture efficiency.

    Science.gov (United States)

    Sakura, Midori; Takasuga, Kyo; Watanabe, Mami; Eguchi, Eisuke

    2003-07-01

    Day-night changes in rhabdom size of compound eyes were investigated in three groups of crickets (Gryllus bimaculatus): nymphs and adult males and females. In both adults and nymphs, the rhabdoms were larger at night than during a day. In adults, the mean rhabdom occupation ratios (RORs) of ommatidial retinulae at midnight were about two times greater than the values at midday. This change contributes to control of the photon capture efficiency (PCE) of the eye according to photic environment. The RORs of adult males at midnight were higher than those of both adult females and nymphs. This suggests that the PCE of the compound eye of adult males is the greatest of all groups. Under constant darkness, day-night changes in ROR were detected only in adult males, but neither in adult females nor in nymphs. On the other hand, no day-night changes were detected in any experimental group under constant light. These results suggest that the change in rhabdom size between day and night is an adaptation to the photic environment that is controlled mainly by the light-dark (day-night) cycle. However, the change in male adults is induced by an endogenous circadian clock.

  10. Direct fabrication of compound-eye microlens array on curved surfaces by a facile femtosecond laser enhanced wet etching process

    Science.gov (United States)

    Bian, Hao; Wei, Yang; Yang, Qing; Chen, Feng; Zhang, Fan; Du, Guangqing; Yong, Jiale; Hou, Xun

    2016-11-01

    We report a direct fabrication of an omnidirectional negative microlens array on a curved substrate by a femtosecond laser enhanced chemical etching process, which is utilized as a molding template for duplicating bioinspired compound eyes. The femtosecond laser treatment of the curved glass substrate employs a common x-y-z stage without rotating the sample surface perpendicular to the laser beam, and uniform, omnidirectional-aligned negative microlenses are generated after a hydrofluoric acid etching. Using the negative microlens array on the concave glass substrate as a molding template, we fabricate an artificial compound eye with 3000 positive microlenses of 95-μm diameter close-packed on a 5-mm polymer hemisphere. Compared to the transferring process, the negative microlenses directly fabricated on the curved mold by our method are distortion-free, and the duplicated artificial eye presents clear and uniform imaging capabilities. This work provides a facile and efficient route to the fabrication of microlenses on any curved substrates without complicated alignment and motion control processes, which has the potential for the development of new microlens-based devices and systems.

  11. Conservative whole-organ scaling contrasts with highly labile suborgan scaling differences among compound eyes of closely related Formica ants.

    Science.gov (United States)

    Perl, Craig D; Rossoni, Sergio; Niven, Jeremy E

    2017-03-01

    Static allometries determine how organ size scales in relation to body mass. The extent to which these allometric relationships are free to evolve, and how they differ among closely related species, has been debated extensively and remains unclear; changes in intercept appear common, but changes in slope are far rarer. Here, we compare the scaling relationships that govern the structure of compound eyes of four closely related ant species from the genus Formica. Comparison among these species revealed changes in intercept but not slope in the allometric scaling relationships governing eye area, facet number, and mean facet diameter. Moreover, the scaling between facet diameter and number was conserved across all four species. In contrast, facet diameters from distinct regions of the compound eye differed in both intercept and slope within a single species and when comparing homologous regions among species. Thus, even when species are conservative in the scaling of whole organs, they can differ substantially in regional scaling within organs. This, at least partly, explains how species can produce organs that adhere to genus wide scaling relationships while still being able to invest differentially in particular regions of organs to produce specific features that match their ecology.

  12. Verifying quantum superpositions at metre scales

    CERN Document Server

    Stamper-Kurn, Dan M; Müller, Holger

    2016-01-01

    While the existence of quantum superpositions of massive particles over microscopic separations has been established since the birth of quantum mechanics, the maintenance of superposition states over macroscopic separations is a subject of modern experimental tests. In Ref. [1], T. Kovachy et al. report on applying optical pulses to place a freely falling Bose-Einstein condensate into a superposition of two trajectories that separate by an impressive distance of 54 cm before being redirected toward one another. When the trajectories overlap, a final optical pulse produces interference with high contrast, but with random phase, between the two wave packets. Contrary to claims made in Ref. [1], we argue that the observed interference is consistent with, but does not prove, that the spatially separated atomic ensembles were in a quantum superposition state. Therefore, the persistence of such superposition states remains experimentally unestablished.

  13. Fine structural description of the compound eye of the Madagascar 'hissing cockroach' Gromphadorhina portentosa(Dictyoptera: Blaberidae)

    Institute of Scientific and Technical Information of China (English)

    Monalisa Mishra; Victor Benno Meyer-Rochow

    2008-01-01

    The compound eyes of the wingless adults of the Madagascar' hissing cockroach' Gromphador hina portentosa Sachum, 1853 were examined by light and electron microscopy.Each eye contains 2 400-2 500 mostly hexagonal facets. However, irregularities affecting both shape and size of the ommatidia are relatively common, especially towards the margins of the eye. An individual ommatidium of this eucone type of apposition eye contains eight retinula cells, which give rise to a centrally-fused, tiered rhabdom. The distal end of the latter is funnel-shaped and accommodates the proximal end of the cone in its midst. Further below, the rhabdom (then formed by the rhabdomeres of four retinula cells) assumes a squarish profile with microvilli aligned in two directions at right-angle to each other. Cross sections through the proximal regions of the rhabdom display triangular rhabdom outlines and microvilli (belonging to 3-4 retinula cells different from those involved in the squarish more distal rhabdom) that run in three directions inclined to one another by 120°. Overall the organization of the eye conforms to the orthopteroid pattern and particularly closely resembles that of the American cockroach Periplaneta americana. However, since G.portentosa possesses fewer ommatidia, this could be a consequence of its inability to fly. On the other hand, the large size of the facets and the voluminous rhabdoms suggest considerable absolute sensitivity and an ability to detect the plane of linearly polarized light. Based on the pattern of rnicrovillus orientations in combination with the crepuscular lifestyle G. portentosa leads and the habitat it occurs in, the prediction is made that this insect uses its green receptors for e-vector discrimination in the environment of down-welling light that reaches the forest floor.

  14. Synthesis and characterization of novel urea and thiourea substitute cyclotriphosphazene compounds as naked-eye sensors for F$^{-}$ and CN$^{-}$ anions

    OpenAIRE

    ÖZAY, HAVA; Yildirim, Mehmet; ÖZAY, ÖZGÜR

    2015-01-01

    Novel hexakisurea and thiourea cyclotriphosphazene compounds (3-7) were synthesized. The structure of all compounds was identified using FT-IR $^{1}$H, $^{13}$C, and $^{31}$P NMR spectroscopy; MALDI-TOF MS; and elemental analysis. The optical sensor properties for anions of 3-7 were investigated using UV-Vis spectroscopy. It was determined that compounds 6 and 7 are spectrophotometric and naked eye sensors for F$^{-}$ and CN$^{-}$ anions, respectively. Sensor properties of these compounds for...

  15. Multifunctional ZnO interfaces with hierarchical micro- and nanostructures: bio-inspiration from the compound eyes of butterflies

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Sha; Yang, Yefeng; Jin, Yizheng; Huang, Jingyun; Zhao, Binghui; Ye, Zhizhen [Zhejiang University, State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Hangzhou (China)

    2010-07-15

    Multifunctional zinc oxide (ZnO) interfaces were fabricated by utilizing the technique of low-temperature metal-organic chemical vapor deposition (MOCVD). The ZnO interfacial material exhibit antiwetting, antireflectance, and photonic properties derived from the unique hierarchical micro- and nanostructures of the compound eye of the butterflies. We demonstrate that the fabrication of the multifunctional interfaces by using biotemplates can be applied to other materials, such as Pt. Our study provides an excellent example to obtain multifunctional interfaces by learning from nature. (orig.)

  16. Mixed superposition rules and the Riccati hierarchy

    Science.gov (United States)

    Grabowski, Janusz; de Lucas, Javier

    Mixed superposition rules, i.e., functions describing the general solution of a system of first-order differential equations in terms of a generic family of particular solutions of first-order systems and some constants, are studied. The main achievement is a generalization of the celebrated Lie-Scheffers Theorem, characterizing systems admitting a mixed superposition rule. This somehow unexpected result says that such systems are exactly Lie systems, i.e., they admit a standard superposition rule. This provides a new and powerful tool for finding Lie systems, which is applied here to studying the Riccati hierarchy and to retrieving some known results in a more efficient and simpler way.

  17. Mixed superposition rules and the Riccati hierarchy

    CERN Document Server

    Grabowski, Janusz

    2012-01-01

    Mixed superposition rules, i.e., functions describing the general solution of a system of first-order differential equations in terms of a generic family of particular solutions of first-order systems and some constants, are studied. The main achievement is a generalization of the celebrated Lie-Scheffers Theorem, characterizing systems admitting a mixed superposition rule. This somehow unexpected result says that such systems are exactly Lie systems, i.e., they admit a standard superposition rule. This provides a new and powerful tool for finding Lie systems, which is applied here to studying the Riccati hierarchy and to retrieving some known results in a more efficient and simpler way.

  18. Decoherence of superposition states in trapped ions

    CSIR Research Space (South Africa)

    Uys, H

    2010-09-01

    Full Text Available This paper investigates the decoherence of superpositions of hyperfine states of 9Be+ ions due to spontaneous scattering of off-resonant light. It was found that, contrary to conventional wisdom, elastic Raleigh scattering can have major...

  19. Robust Mesoscopic Superposition of Ultracold Atoms

    CERN Document Server

    Hallwood, David W; Brand, Joachim

    2010-01-01

    Quantum superpositions of macroscopically distinct states, as in Schroedinger's example of a dead and alive cat, are important for our understanding of quantum mechanics and carry great promise for enhanced precision measurement techniques. Due to their inherent fragility, the maximally entangled "NOON" states engineered in optics and spin systems for ultra-precise spectroscopy have been limited to 10 particles. The related mesoscopic superpositions of flux states consisting of 10^9 Cooper pairs observed in superconducting rings have proven more robust but their microscopic nature is debated. Binary superpositions with multiple ultra-cold atoms have not yet been seen and existing proposals suffer severe limitations due to decoherence and the unfavorable scaling of precision and time scales needed to produce these states. In this paper we show how robust superpositions of mesoscopic flow in a ring trap can be made with strongly-correlated ultra-cold atoms under one-dimensional confinement. We present a microsc...

  20. A reciprocal space approach for locating symmetry elements in Patterson superposition maps

    Energy Technology Data Exchange (ETDEWEB)

    Hendrixson, T.

    1990-09-21

    A method for determining the location and possible existence of symmetry elements in Patterson superposition maps has been developed. A comparison of the original superposition map and a superposition map operated on by the symmetry element gives possible translations to the location of the symmetry element. A reciprocal space approach using structure factor-like quantities obtained from the Fourier transform of the superposition function is then used to determine the best'' location of the symmetry element. Constraints based upon the space group requirements are also used as a check on the locations. The locations of the symmetry elements are used to modify the Fourier transform coefficients of the superposition function to give an approximation of the structure factors, which are then refined using the EG relation. The analysis of several compounds using this method is presented. Reciprocal space techniques for locating multiple images in the superposition function are also presented, along with methods to remove the effect of multiple images in the Fourier transform coefficients of the superposition map. In addition, crystallographic studies of the extended chain structure of (NHC{sub 5}H{sub 5})SbI{sub 4} and of the twinning method of the orthorhombic form of the high-{Tc} superconductor YBa{sub 2}Cu{sub 3}O{sub 7-x} are presented. 54 refs.

  1. 多孔径仿生复眼成像系统技术进展综述%Progress of Multiaperture Bionic Compound Eye Imaging Systems

    Institute of Scientific and Technical Information of China (English)

    金伟其; 林青; 裘溯; 米凤文

    2011-01-01

    Insects' compound eye is an ideal intelligence imaging system with the advantages of miniaturization, multiaperture and wide field of view. Although each ommatidium's aperture size and numerical aperture are very small which cause the poor eyesight of insects, the compound eye has high sensitivity to moving targets and high difference to light intensity, wavelenth and color. The researchers for a long time were absorbed in the research of the characteristics and composition of insects' compound eye. The common types of compound eye and present bionic compound eye were thoroughly analysised. The technical characteristics and composition of different bionic compound eye were compared with each other. Development tendency of this field was discussed.%昆虫复眼是一种理想的小型化、多孔径、大视场的视觉系统,具有智能特征,虽然由于每个复眼的孔径尺寸和数值孔径都很小,使昆虫复眼的视力较差,但是其对运动目标却有很高的探测灵敏度,且对光的强度、波长和颜色等都有较强的分辨力。长期以来,人们一直致力于昆虫复眼的特性以及仿生昆虫复眼的研究。对目前常见的复眼类型和现有的各种类型的仿生复眼系统研究进展进行了深入分析,对比了各种类型仿生复眼系统的结构和技术特点,并对仿生复眼系统的发展趋势进行了展望。

  2. Scan Quantum Mechanics: Quantum Inertia Stops Superposition

    CERN Document Server

    Gato-Rivera, Beatriz

    2015-01-01

    A novel interpretation of the quantum mechanical superposition is put forward. Quantum systems scan all possible available states and switch randomly and very rapidly among them. The longer they remain in a given state, the larger the probability of the system to be found in that state during a measurement. A crucial property that we postulate is quantum inertia, that increases whenever a constituent is added, or the system is perturbed with all kinds of interactions. Once the quantum inertia $I_q$ reaches a critical value $I_{cr}$ for an observable, the switching among the different eigenvalues of that observable stops and the corresponding superposition comes to an end. Consequently, increasing the mass, temperature, gravitational force, etc. of a quantum system increases its quantum inertia until the superposition of states disappears for all the observables and the system transmutes into a classical one. The process could be reversible decreasing the size, temperature, gravitational force, etc. leading to...

  3. Photoreceptor spectral sensitivity of the compound eyes of black soldier fly (Hermetia illucens) informing the design of LED-based illumination to enhance indoor reproduction

    NARCIS (Netherlands)

    Oonincx, D.G.A.B.; Volk, N.; Diehl, J.J.E.; Loon, van J.J.A.; Belušič, G.

    2016-01-01

    Mating in the black soldier fly (BSF) is a visually mediated behaviour that under natural conditions occurs in full sunlight. Artificial light conditions promoting mating by BSF were designed based on the spectral characteristics of the compound eye retina. Electrophysiological measurements

  4. Photoreceptor spectral sensitivity of the compound eyes of black soldier fly (Hermetia illucens) informing the design of LED-based illumination to enhance indoor reproduction

    NARCIS (Netherlands)

    Oonincx, D.G.A.B.; Volk, N.; Diehl, J.J.E.; Loon, van J.J.A.; Belušič, G.

    2016-01-01

    Mating in the black soldier fly (BSF) is a visually mediated behaviour that under natural conditions occurs in full sunlight. Artificial light conditions promoting mating by BSF were designed based on the spectral characteristics of the compound eye retina. Electrophysiological measurements revea

  5. The spatial resolutions of the apposition compound eye and its neuro-sensory feature detectors: observation versus theory.

    Science.gov (United States)

    Horridge, Adrian

    2005-03-01

    For 100 years three ideas dominated efforts to understand the apposition compound eye. In Müller's theory, the eye viewed the panorama through an array of little windows without overlaps and without gaps, with no details within windows. Spatial resolution then depended on the interommatidial angle (Deltaphi) and the number of ommatidia. In the second proposal, the insect detected the temporal modulation of the light, which was limited by the aperture of the lens and the wavelength, assuming good focus. Modulation is the change of intensity in the receptor, usually caused by motion of a spatial contrast in the stimulus. Thirdly, motion was detected from the successive temporal modulations at adjacent visual axes. Recently, two more principles arose. The light-sensitive elements, called rhabdomeres, project through the nodal point of the lens to the outside world, and the resolution was limited by their grain size, like the pixels in a digital camera. Finally, detection of contrast and colour was limited by the signal/noise ratio (SNR) which was improved by brighter light and more visual pigment. These five physical principles provide satisfying explanations of eye function but they all originated from theory. Actual measurements of resolution depend on the operation of the test. The visual system of the honeybee recognizes a limited variety of simple cues, but there is no evidence that the pattern of ommatidial stimulation is re-assembled, or even seen. The known cues are: the temporal modulation of groups of receptors, the direction and angular velocity of motion, some measure of the spatial disruption of the pattern or the length of edge (related to spatial frequency and contrast), colour, the intensity, the position of the centre and the size of large well-separated areas of black or colour, the angle of orientation of a bar or grating, radial or tangential edges, and bilateral symmetry. Neurons connected to more than two adjacent ommatidia collaborate in the

  6. SUPERPOSITION OF POLYTROPES IN THE INNER HELIOSHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Livadiotis, G., E-mail: glivadiotis@swri.edu [Southwest Research Institute, San Antonio, TX (United States)

    2016-03-15

    This paper presents a possible generalization of the equation of state and Bernoulli's integral when a superposition of polytropic processes applies in space and astrophysical plasmas. The theory of polytropic thermodynamic processes for a fixed polytropic index is extended for a superposition of polytropic indices. In general, the superposition may be described by any distribution of polytropic indices, but emphasis is placed on a Gaussian distribution. The polytropic density–temperature relation has been used in numerous analyses of space plasma data. This linear relation on a log–log scale is now generalized to a concave-downward parabola that is able to describe the observations better. The model of the Gaussian superposition of polytropes is successfully applied in the proton plasma of the inner heliosheath. The estimated mean polytropic index is near zero, indicating the dominance of isobaric thermodynamic processes in the sheath, similar to other previously published analyses. By computing Bernoulli's integral and applying its conservation along the equator of the inner heliosheath, the magnetic field in the inner heliosheath is estimated, B ∼ 2.29 ± 0.16 μG. The constructed normalized histogram of the values of the magnetic field is similar to that derived from a different method that uses the concept of large-scale quantization, bringing incredible insights to this novel theory.

  7. Generation of picosecond pulsed coherent state superpositions

    DEFF Research Database (Denmark)

    Dong, Ruifang; Tipsmark, Anders; Laghaout, Amine

    2014-01-01

    We present the generation of approximated coherent state superpositions-referred to as Schrodinger cat states-by the process of subtracting single photons from picosecond pulsed squeezed states of light. The squeezed vacuum states are produced by spontaneous parametric down-conversion (SPDC...

  8. Towards Quantum Superposition of Living Organisms

    CERN Document Server

    Romero-Isart, Oriol; Quidant, Romain; Cirac, J Ignacio

    2009-01-01

    The most striking feature of quantum mechanics is the existence of superposition states, where an object appears to be in different situations at the same time. Up to now, the existence of such states has been tested with small objects, like atoms, ions, electrons and photons, and even with molecules. Recently, it has been even possible to create superpositions of collections of photons, atoms, or Cooper pairs. Current progress in optomechanical systems may soon allow us to create superpositions of even larger objects, like micro-sized mirrors or cantilevers, and thus to test quantum mechanical phenomena at larger scales. Here we propose a method to cool down and create quantum superpositions of the motion of sub-wavelength, arbitrarily shaped dielectric objects trapped inside a high--finesse cavity at a very low pressure. Our method is ideally suited for the smallest living organisms, such as viruses, which survive under low vacuum pressures, and optically behave as dielectric objects. This opens up the poss...

  9. The principle of superposition in human prehension.

    Science.gov (United States)

    Zatsiorsky, Vladimir M; Latash, Mark L; Gao, Fan; Shim, Jae Kun

    2004-03-01

    The experimental evidence supports the validity of the principle of superposition for multi-finger prehension in humans. Forces and moments of individual digits are defined by two independent commands: "Grasp the object stronger/weaker to prevent slipping" and "Maintain the rotational equilibrium of the object". The effects of the two commands are summed up.

  10. Periodic Trends in Lanthanide Compounds through the Eyes of Multireference ab Initio Theory.

    Science.gov (United States)

    Aravena, Daniel; Atanasov, Mihail; Neese, Frank

    2016-05-01

    Regularities among electronic configurations for common oxidation states in lanthanide complexes and the low involvement of f orbitals in bonding result in the appearance of several periodic trends along the lanthanide series. These trends can be observed on relatively different properties, such as bonding distances or ionization potentials. Well-known concepts like the lanthanide contraction, the double-double (tetrad) effect, and the similar chemistry along the lanthanide series stem from these regularities. Periodic trends on structural and spectroscopic properties are examined through complete active space self-consistent field (CASSCF) followed by second-order N-electron valence perturbation theory (NEVPT2) including both scalar relativistic and spin-orbit coupling effects. Energies and wave functions from electronic structure calculations are further analyzed in terms of ab initio ligand field theory (AILFT), which allows one to rigorously extract angular overlap model ligand field, Racah, and spin-orbit coupling parameters directly from high-level ab initio calculations. We investigated the elpasolite Cs2NaLn(III)Cl6 (Ln(III) = Ce-Nd, Sm-Eu, Tb-Yb) crystals because these compounds have been synthesized for most Ln(III) ions. Cs2NaLn(III)Cl6 elpasolites have been also thoroughly characterized with respect to their spectroscopic properties, providing an exceptionally vast and systematic experimental database allowing one to analyze the periodic trends across the lanthanide series. Particular attention was devoted to the apparent discrepancy in metal-ligand covalency trends between theory and spectroscopy described in the literature. Consistent with earlier studies, natural population analysis indicates an increase in covalency along the series, while a decrease in both the nephelauxetic (Racah) and relativistic nephelauxetic (spin-orbit coupling) reduction with increasing atomic number is calculated. These apparently conflicting results are discussed on the

  11. Quantum inertia stops superposition: Scan Quantum Mechanics

    Science.gov (United States)

    Gato-Rivera, Beatriz

    2017-08-01

    Scan Quantum Mechanics is a novel interpretation of some aspects of quantum mechanics in which the superposition of states is only an approximate effective concept. Quantum systems scan all possible states in the superposition and switch randomly and very rapidly among them. A crucial property that we postulate is quantum inertia, that increases whenever a constituent is added, or the system is perturbed with all kinds of interactions. Once the quantum inertia Iq reaches a critical value Icr for an observable, the switching among its different eigenvalues stops and the corresponding superposition comes to an end, leaving behind a system with a well defined value of that observable. Consequently, increasing the mass, temperature, gravitational strength, etc. of a quantum system increases its quantum inertia until the superposition of states disappears for all the observables and the system transmutes into a classical one. Moreover, the process could be reversible. Entanglement can only occur between quantum systems because an exact synchronization between the switchings of the systems involved must be established in the first place and classical systems do not have any switchings to start with. Future experiments might determine the critical inertia Icr corresponding to different observables, which translates into a critical mass Mcr for fixed environmental conditions as well as critical temperatures, critical electric and magnetic fields, etc. In addition, this proposal implies a new radiation mechanism from astrophysical objects with strong gravitational fields, giving rise to non-thermal synchrotron emission, that could contribute to neutron star formation. Superconductivity, superfluidity, Bose-Einstein condensates, and any other physical phenomena at very low temperatures must be reanalyzed in the light of this interpretation, as well as mesoscopic systems in general.

  12. Toward quantum superposition of living organisms

    Science.gov (United States)

    Romero-Isart, Oriol; Juan, Mathieu L.; Quidant, Romain; Cirac, J. Ignacio

    2010-03-01

    The most striking feature of quantum mechanics is the existence of superposition states, where an object appears to be in different situations at the same time. The existence of such states has been previously tested with small objects, such as atoms, ions, electrons and photons (Zoller et al 2005 Eur. Phys. J. D 36 203-28), and even with molecules (Arndt et al 1999 Nature 401 680-2). More recently, it has been shown that it is possible to create superpositions of collections of photons (Deléglise et al 2008 Nature 455 510-14), atoms (Hammerer et al 2008 arXiv:0807.3358) or Cooper pairs (Friedman et al 2000 Nature 406 43-6). Very recent progress in optomechanical systems may soon allow us to create superpositions of even larger objects, such as micro-sized mirrors or cantilevers (Marshall et al 2003 Phys. Rev. Lett. 91 130401; Kippenberg and Vahala 2008 Science 321 1172-6 Marquardt and Girvin 2009 Physics 2 40; Favero and Karrai 2009 Nature Photon. 3 201-5), and thus to test quantum mechanical phenomena at larger scales. Here we propose a method to cool down and create quantum superpositions of the motion of sub-wavelength, arbitrarily shaped dielectric objects trapped inside a high-finesse cavity at a very low pressure. Our method is ideally suited for the smallest living organisms, such as viruses, which survive under low-vacuum pressures (Rothschild and Mancinelli 2001 Nature 406 1092-101) and optically behave as dielectric objects (Ashkin and Dziedzic 1987 Science 235 1517-20). This opens up the possibility of testing the quantum nature of living organisms by creating quantum superposition states in very much the same spirit as the original Schrödinger's cat 'gedanken' paradigm (Schrödinger 1935 Naturwissenschaften 23 807-12, 823-8, 844-9). We anticipate that our paper will be a starting point for experimentally addressing fundamental questions, such as the role of life and consciousness in quantum mechanics.

  13. 复方碘化钾滴眼液无菌检查方法的验证%Validation of sterility test of compound potassium iodide eye drops

    Institute of Scientific and Technical Information of China (English)

    余晓霞; 邱凯锋; 廖庆权

    2014-01-01

    目的:建立复方碘化钾滴眼液无菌检查方法。方法按《中国药典》2010年版二部无菌检查法中薄膜过滤法对复方碘化钾滴眼液的无菌检查方法进行验证。结果该制剂的无菌检查选用薄膜过滤法,以金黄色葡萄球菌为阳性对照菌,冲洗总量100 ml。结论经方法学验证,该法可行,结果可靠。%ObjectiveTo establish the method of sterility test of compound potassium iodide eye drops. MethodsAccording to sterility test in the appendix ofChinese Pharmacopoeia 2010 (section 2), the membrane filteration used in the sterility test of compound potassium iodide eye drops was validated.ResultsThe membrane filteration was used in the sterility test of compound potassium iodide eye drops, and staphylococcus aureus was used as positive control germs and the total amount of irrigation fluid was 100 ml.Conclusion Through the technological validation, the method is applicable and the result is reliable.

  14. Dry Eye

    Science.gov (United States)

    ... Eye > Facts About Dry Eye Facts About Dry Eye This information was developed by the National Eye ... the best person to answer specific questions. Dry Eye Defined What is dry eye? Dry eye occurs ...

  15. Eye Allergies

    Science.gov (United States)

    ... Español Eye Health / Eye Health A-Z Eye Allergies Sections What Are Eye Allergies? Eye Allergy Symptoms ... allergy diagnosis Eye allergy treatment What Are Eye Allergies? Written by: David Turbert Reviewed by: Brenda Pagan- ...

  16. Optimal Control of the Compensatory Eye Movement System

    NARCIS (Netherlands)

    T.M. Sibindi (Tafadzwa)

    2015-01-01

    markdownabstractIn this thesis, we utilized behavioural, electrophysiological, computational and stimulation techniques to delve our knowledge further into the functional neural network of the compensatory eye movement system (CEM). We first investigated the superposition violations and non-lineari

  17. 非球面复眼设计及其制备工艺研究%Design and preparation of aspherical compound eye

    Institute of Scientific and Technical Information of China (English)

    郝永平; 李伦; 于军波

    2016-01-01

    提出了一种制备非球面仿生复眼的方法。昆虫的复眼是由一个个尺寸微小的独立小眼沿曲面小眼阵列的方式分布在头部的两侧,以实现大视角探测。设计曲面基底上阵列非均匀微透镜结构,沿径向排列的各级微透镜的焦距及尺寸均不相同。根据几何光学成像原理,计算各级微透镜的尺寸参数,对构建的模型进行光线追迹,优化各级微透镜的尺寸参数。分析不同制备技术特点,研究材料性能及不同材料间的关系,提出了可简单、快速的制备非球面仿生复眼的方法。该方法中,利用精密五轴数控机床加工非球面复眼模具,然后通过压力灌注方法将非球面复眼结构转移出来,获得所需的非球面仿生复眼。通过仿真及实验结果表明,整个曲面仿生复眼边缘成像质量明显提高,各子眼通道均能够采集清晰亮斑。%A preparation method for aspherical bionic compound eye is proposed.The compound eyes of insects are composed of many tiny independent ommatidia,and these ommatidia along the surface of the array distribute on both sides of the head to achieve large angle viewing.The array of non-uniform substrate surface is designed for micro-lens structure,and the focal lengths and sizes of radial arrayed micro-lenses are all different.According to geometrical op-tics imaging principle,size parameters of all level micro-lenses are computed,and the constructed model is carried out by ray-tracing and the size parameters of all level micro-lenses are optimized.The technical characteristics of different preparation methods are analyzed,and material properties and the relationship between different materials are studied, so a simple and fast preparation method for aspherical bionic compound eye is proposed.In this method,the mold of aspherical compound eyes is manufactured by precise five-axis CNC machine and then the aspheric compound eye structure is transferred

  18. Multipartite cellular automata and the superposition principle

    Science.gov (United States)

    Elze, Hans-Thomas

    2016-05-01

    Cellular automata (CA) can show well known features of quantum mechanics (QM), such as a linear updating rule that resembles a discretized form of the Schrödinger equation together with its conservation laws. Surprisingly, a whole class of “natural” Hamiltonian CA, which are based entirely on integer-valued variables and couplings and derived from an action principle, can be mapped reversibly to continuum models with the help of sampling theory. This results in “deformed” quantum mechanical models with a finite discreteness scale l, which for l→0 reproduce the familiar continuum limit. Presently, we show, in particular, how such automata can form “multipartite” systems consistently with the tensor product structures of non-relativistic many-body QM, while maintaining the linearity of dynamics. Consequently, the superposition principle is fully operative already on the level of these primordial discrete deterministic automata, including the essential quantum effects of interference and entanglement.

  19. Wave Superposition Based Sound Field Reconstruction

    Institute of Scientific and Technical Information of China (English)

    LI Jia-qing; CHEN Jin; YANG Chao

    2008-01-01

    In order to overcome the obstacle of singular integral in boundary element method (BEM), wepresented an efficient sound field reconstruction technique based on the wave superposition method (WSM). Itsprinciple includes three steps: first, the sound pressure field of an arbitrary shaped radiator is measured witha microphone array; then, the exterior sound field of the radiator is computed backward and forward using theWSM; at last, the final results are visualized in terms of sound pressure contours or animations. With thesevisualized contours or animations, noise sources can be easily located and quantified; also noise transmissionpath can be found out. By numerical simulation and experimental results, we proved that the technique aresuitable and accurate for sound field reconstruction. In addition, we presented a sound field reconstruction sys-tem prototype on the basis of this technique. It makes a foundation for the application of wave superpositionin the sound field reconstruction in industry situations.

  20. Superposition rules and second-order Riccati equations

    CERN Document Server

    Cariñena, J F

    2010-01-01

    The concept of superposition rule for second-order differential equations is stated and conditions ensuring the existence of such superposition rules are analysed. In this way, second-order differential equations become formally included within the theory of Lie systems. The theory is illustrated by analysing the properties of a family of second-order differential equations with applications to Physics and we obtain a superposition rule common for all its members. Finally, time-dependent superposition rules for second-order differential equations are defined and we derive a particular instance for a family of second-order Riccati equations by means of the theory of quasi-Lie schemes.

  1. Superposition and alignment of labeled point clouds.

    Science.gov (United States)

    Fober, Thomas; Glinca, Serghei; Klebe, Gerhard; Hüllermeier, Eyke

    2011-01-01

    Geometric objects are often represented approximately in terms of a finite set of points in three-dimensional euclidean space. In this paper, we extend this representation to what we call labeled point clouds. A labeled point cloud is a finite set of points, where each point is not only associated with a position in three-dimensional space, but also with a discrete class label that represents a specific property. This type of model is especially suitable for modeling biomolecules such as proteins and protein binding sites, where a label may represent an atom type or a physico-chemical property. Proceeding from this representation, we address the question of how to compare two labeled points clouds in terms of their similarity. Using fuzzy modeling techniques, we develop a suitable similarity measure as well as an efficient evolutionary algorithm to compute it. Moreover, we consider the problem of establishing an alignment of the structures in the sense of a one-to-one correspondence between their basic constituents. From a biological point of view, alignments of this kind are of great interest, since mutually corresponding molecular constituents offer important information about evolution and heredity, and can also serve as a means to explain a degree of similarity. In this paper, we therefore develop a method for computing pairwise or multiple alignments of labeled point clouds. To this end, we proceed from an optimal superposition of the corresponding point clouds and construct an alignment which is as much as possible in agreement with the neighborhood structure established by this superposition. We apply our methods to the structural analysis of protein binding sites.

  2. 仿复眼视觉系统的研究进展%Research progress on artificial visual system inspired by compound eyes

    Institute of Scientific and Technical Information of China (English)

    邢强; 戴振东; 王浩

    2013-01-01

    Compound eye is one of the most important peripheral sensors in insects,which consists of thousands of ommatidia.The compound eye is characterized as multi-aperture imaging and fast parallel processing,which insures the ability of fast detection and location on obstacles and predators.These characteristics have been widely recognized in several research fields,such as robot visual navigation,obstacle avoidance,machine vision,guided missile.Firstly,the biological mechanism,imaging features,and the existed large field visual system of the compound eyes were introduced; secondly,the different optical systems designed with micro lens array imitation from compound eyes,the panoramic image quality with large field of view and depth field,and the surface micro-lens imaging defects were discussed;finally,the idea of combining the surf and plane micro lens array to achieve a system with large field of view and large depth of field was proposed.Based on the judgment of quality in panoramic images,position estimation of such a system can be achieved in detecting multiple moving targets.%复眼是昆虫重要的光感受器,由成千上万的小眼构成,具有大视野的动目标快速检测能力.仿复眼的多孔径系统在机器人视觉导航、大视角测量和全景成像等领域应用广泛.首先介绍了复眼的生物机理、成像特性及现有的大视场成像系统;其次介绍了微透镜阵列的仿复眼光学设计现状,分析了微透镜阵列的大视角与多景深的全景成像质量,指出目前曲面微透镜一体化制造存在的成像缺陷;最后提出结合曲面与平面微透镜阵列实现大视角、多景深分辨率的仿复眼系统的可行性.该成像系统不仅可以实现全景范围内的清晰成像,而且还具有全景范围内的目标位置估计能力.

  3. Generation of optical coherent state superpositions for quantum information processing

    DEFF Research Database (Denmark)

    Tipsmark, Anders

    2012-01-01

    I dette projektarbejde med titlen “Generation of optical coherent state superpositions for quantum information processing” har målet været at generere optiske kat-tilstande. Dette er en kvantemekanisk superpositions tilstand af to koherente tilstande med stor amplitude. Sådan en tilstand er...

  4. Teleportation of Unknown Superpositions of Collective Atomic Coherent States

    Institute of Scientific and Technical Information of China (English)

    ZHENG ShiBiao

    2001-01-01

    We propose a scheme to teleport an unknown superposition of two atomic coherent states with different phases. Our scheme is based on resonant and dispersive atom-field interaction. Our scheme provides a possibility of teleporting macroscopic superposition states of many atoms first time.``

  5. Controlled Creation of Spatial Superposition States for Single Atoms

    CERN Document Server

    Deasy, K; Chormaic, S N; Gong, S; Jin, S; Niu, Y; Busch, Th.

    2006-01-01

    We present a method for the controlled and robust generation of spatial superposition states of single atoms in micro-traps. Using a counter-intuitive positioning sequence for the individual potentials and appropriately chosen trapping frequencies, we show that it is possible to selectively create two different orthogonal superposition states, which can in turn be used for quantum information purposes.

  6. A new look at an old visual system: structure and development of the compound eyes and optic ganglia of the brine shrimp Artemia salina Linnaeus, 1758 (Branchiopoda, anostraca).

    Science.gov (United States)

    Wildt, Miriam; Harzsch, Steffen

    2002-08-01

    Compared to research carried out on decapod crustaceans, the development of the visual system in representatives of the entomostracan crustaceans is poorly understood. However, the structural evolution of the arthropod visual system is an important topic in the new debate on arthropod relationships, and entomostracan crustaceans play a key role in this discussion. Hence, data on structure and ontogeny of the entomostracan visual system are likely to contribute new aspects to our understanding of arthropod phylogeny. Therefore, we explored the proliferation of neuronal stem cells (in vivo incorporation of bromodeoxyuridine) and the developmental expression of synaptic proteins (immunohistochemistry against synapsins) in the developing optic neuropils of the brine shrimp Artemia salina Linnaeus, 1758 (Crustacea, Entomostraca, Branchiopoda, Anostraca) from hatching to adulthood. The morphology of the adult visual system was examined in serial sections of plastic embedded specimens. Our results indicate that the cellular material that gives rise to the visual system (compound eyes and two optic ganglia) is contributed by the mitotic activity of neuronal stem cells that are arranged in three band-shaped proliferation zones. Synapsin-like immunoreactivity in the lamina ganglionaris and the medulla externa initiated only after the anlagen of the compound eyes had already formed, suggesting that the emergence of the two optic neuropils lags behind the proliferative action of these stem cells. Neurogenesis in A. salina is compared to similar processes in malacostracan crustaceans and possible phylogenetic implications are discussed.

  7. Flight Morphology, Compound Eye Structure and Dispersal in the Bog and the Cranberry Fritillary Butterflies: An Inter- and Intraspecific Comparison.

    Science.gov (United States)

    Turlure, Camille; Schtickzelle, Nicolas; Van Dyck, Hans; Seymoure, Brett; Rutowski, Ronald

    2016-01-01

    Understanding dispersal is of prime importance in conservation and population biology. Individual traits related to motion and navigation during dispersal may differ: (1) among species differing in habitat distribution, which in turn, may lead to interspecific differences in the potential for and costs of dispersal, (2) among populations of a species that experiences different levels of habitat fragmentation; (3) among individuals differing in their dispersal strategy and (4) between the sexes due to sexual differences in behaviour and dispersal tendencies. In butterflies, the visual system plays a central role in dispersal, but exactly how the visual system is related to dispersal has received far less attention than flight morphology. We studied two butterfly species to explore the relationships between flight and eye morphology, and dispersal. We predicted interspecific, intraspecific and intersexual differences for both flight and eye morphology relative to i) species-specific habitat distribution, ii) variation in dispersal strategy within each species and iii) behavioural differences between sexes. However, we did not investigate for potential population differences. We found: (1) sexual differences that presumably reflect different demands on both male and female visual and flight systems, (2) a higher wing loading (i.e. a proxy for flight performance), larger eyes and larger facet sizes in the frontal and lateral region of the eye (i.e. better navigation capacities) in the species inhabiting naturally fragmented habitat compared to the species inhabiting rather continuous habitat, and (3) larger facets in the frontal region in dispersers compared to residents within a species. Hence, dispersers may have similar locomotory capacity but potentially better navigation capacity. Dispersal ecology and evolution have attracted much attention, but there are still significant gaps in our understanding of the mechanisms of dispersal. Unfortunately, for many species

  8. Accurate structural correlations from maximum likelihood superpositions.

    Directory of Open Access Journals (Sweden)

    Douglas L Theobald

    2008-02-01

    Full Text Available The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. Accurate analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly accurate technique for inferring the major modes of structural correlation in macromolecules using likelihood-based statistical analysis of sets of structures. This method is generally applicable to any ensemble of related molecules, including families of nuclear magnetic resonance (NMR models, different crystal forms of a protein, and structural alignments of homologous proteins, as well as molecular dynamics trajectories. Dominant modes of structural correlation are determined using principal components analysis (PCA of the maximum likelihood estimate of the correlation matrix. The correlations we identify are inherently independent of the statistical uncertainty and dynamic heterogeneity associated with the structural coordinates. We additionally present an easily interpretable method ("PCA plots" for displaying these positional correlations by color-coding them onto a macromolecular structure. Maximum likelihood PCA of structural superpositions, and the structural PCA plots that illustrate the results, will facilitate the accurate determination of dynamic structural correlations analyzed in diverse fields of structural biology.

  9. Macroscopic superpositions and gravimetry with quantum magnetomechanics

    Science.gov (United States)

    Johnsson, Mattias T.; Brennen, Gavin K.; Twamley, Jason

    2016-11-01

    Precision measurements of gravity can provide tests of fundamental physics and are of broad practical interest for metrology. We propose a scheme for absolute gravimetry using a quantum magnetomechanical system consisting of a magnetically trapped superconducting resonator whose motion is controlled and measured by a nearby RF-SQUID or flux qubit. By driving the mechanical massive resonator to be in a macroscopic superposition of two different heights our we predict that our interferometry protocol could, subject to systematic errors, achieve a gravimetric sensitivity of Δg/g ~ 2.2 × 10-10 Hz-1/2, with a spatial resolution of a few nanometres. This sensitivity and spatial resolution exceeds the precision of current state of the art atom-interferometric and corner-cube gravimeters by more than an order of magnitude, and unlike classical superconducting interferometers produces an absolute rather than relative measurement of gravity. In addition, our scheme takes measurements at ~10 kHz, a region where the ambient vibrational noise spectrum is heavily suppressed compared the ~10 Hz region relevant for current cold atom gravimeters.

  10. 仿生复眼结构的制作与测试研究%Fabrication and Test Study of Bionic Compound Eye

    Institute of Scientific and Technical Information of China (English)

    陈德沅; 石云波; 邹坤; 贺婷

    2015-01-01

    为了更好地利用生物复眼的光学性能,介绍了一种新型仿生复眼结构。通过使用传统光刻胶热熔法和NOA73紫外曝光固化技术,得到了NOA73和PDMS材料的微透镜阵列,比较了它们的聚焦效果和光强分布,得到NOA73材料具有更好的光学性能;然后利用PDMS的柔韧性进行了两次倒模,再通过紫外曝光把NOA73固化,得到了背靠背形式的仿生复眼结构;最后对结构进行了成像测试、光强分布测试,并对结果进行了仿真和理论分析,可知该结构具有良好的形貌,光损耗小,光学性能优异并且具有很好的重复性,制作简单,成本低,能够模仿生物复眼的部分光学特性。%This paper presents a novel biomimetic compound eye structure in order to make better use of biological compound eyes’optical properties. We have made NOA73 and PDMS micro-lens array by using conventional photo⁃resist melting method and NOA73 UV curing technology,and certificated NOA73 has better optical performance by comparing their focusing effect and the light intensity distribution. Then using the PDMS flexible characteristics and NOA73 UV curing properties to make the back-to-back bionic compound eye structure. Finally making imaging tests,intensity distribution tests,simulation and theoretical analysis,the result shows that the structure has a good morphology,small optical loss,excellent optical performance and good reproducibility. It is simply made,low cost, and capable of imitating the part of optical properties of biological compound eyes structure.

  11. Eye redness

    Science.gov (United States)

    Bloodshot eyes; Red eyes; Scleral injection; Conjunctival injection ... There are many causes of a red eye or eyes. Some are medical emergencies. Others are a cause for concern, but not an emergency. Many are nothing to worry about. Eye ...

  12. Empirical Evaluation of Superposition Coded Multicasting for Scalable Video

    KAUST Repository

    Chun Pong Lau

    2013-03-01

    In this paper we investigate cross-layer superposition coded multicast (SCM). Previous studies have proven its effectiveness in exploiting better channel capacity and service granularities via both analytical and simulation approaches. However, it has never been practically implemented using a commercial 4G system. This paper demonstrates our prototype in achieving the SCM using a standard 802.16 based testbed for scalable video transmissions. In particular, to implement the superposition coded (SPC) modulation, we take advantage a novel software approach, namely logical SPC (L-SPC), which aims to mimic the physical layer superposition coded modulation. The emulation results show improved throughput comparing with generic multicast method.

  13. Progress in visual processing pathways in compound eyes of bees%蜜蜂复眼的视觉通路研究进展

    Institute of Scientific and Technical Information of China (English)

    赵慧霞; 郑火青; 胡福良

    2012-01-01

    视觉通路的研究在神经科学、仿生应用和医学治疗上都具有十分重要的意义.西方蜜蜂Apis mellifera作为神经生物学研究的重要模式生物已被广泛地应用于视觉通路的研究.蜜蜂的视觉器官包括1对复眼和3只单眼,复眼是形成视觉的主要感觉器官.视叶是蜜蜂传递和处理视觉信息的主要神经构造,它包括视神经节层、视髓质层、视小叶和前视结节4个等级的神经纤维网.复杂的视觉信息在经过大脑的各级神经时被分离,以许多空间隔离的并行连续的视觉通路传递和加工,然后汇集到高级脑中枢,部分甚至与其他感觉模态的信息相整合,最终输出有效信息来调控蜜蜂的各种行为.本文按照信息在视叶中逐级传递的顺序对蜜蜂复眼的视觉通路研究进展进行综述.%Research on the visual processing pathways is of great significance in neuroscience, bionic applications and medical treatments. The western honeybee, Apis mellifera, as an important model organism for neurobiology research, has been extensively applied to the research on visual processing pathways. The visual organs of bees include a pair of compound eyes and three ocelli, in which the compound eyes are most important for vision formation. In bees, processing of visual information is achieved within the optic lobes which are divided into four levels of neuropils, i. e., lamina, medulla, lobula and anterior optic tubercle. Complex visual information is segregated at successive stages within the brain, and processed in many parallel and sequential visual pathways. Then they are converged in higher-order brain centers, with some integrated with information of other modalities, which finally generate effective outputs to regulate and control bee behaviours. In this article, the research on visual processing pathways in bee compound eyes is reviewed according to the sequence of information processing in the optic lobes.

  14. Study and Design on Freeform Surface Compound Eye with Large Field of View%大视场自由曲面复眼设计研究

    Institute of Scientific and Technical Information of China (English)

    范阳; 张红霞; 宋乐; 贾大功

    2014-01-01

    The ommatidia arranged at the edge have great off-axis aberrations in artificial compound eye structure with wide Field of View (FOV) and small volume. A new compound eye structure is presented, where the ommatidia are designed as freeform prisms. With the light passing through the freeform surface and folding in the ommatidium, the off-axis aberrations are well corrected. Therefore, the image quality of the ommatidia arranged at the edge is improved, and the FOV of the structure is enlarged. To image 180° FOV, this structure contains 5 groups of ommatidia with a particular FOV correspondingly. The model of each group is designed and the ray trace is completed based on the optical simulation software codeV. The results demonstrate that the compound eyes structure has high image quality for the entire 180° FOV. On the one hand, the modulation transformation function MTF is greater than 0.2 at the frequency of 100lp/mm, and on the other hand, the distortion is less than 30%.%在大视场小体积的人造复眼结构中,倾斜的边缘子眼成像时存在较大的轴外像差。提出一种复眼结构,利用光线在子眼中的折转与自由曲面矫正像差,提高了边缘子眼的成像质量,进而增大了复眼结构的视场角。设计出5组子眼对180°视场成像,每组对应特定的视场范围。利用光学仿真软件CodeV对5组子眼分别做了光学仿真,得到了各组子眼的像差曲线,光学传递函数 MTF 曲线。结果表明,在整个180°视场范围内,频率为100 lp/mm时,MTF值均大于0.2,畸变在30%以内,复眼具有良好的成像质量。

  15. 仿生复眼接收系统设计与实验%Design and experiment of artificial compound eye receiving system

    Institute of Scientific and Technical Information of China (English)

    谭雪春; 武志超; 梁柱

    2011-01-01

    On the basis of biological visual systems and object recognition technologies, several key technologies of artificial compound eyes, including its structure, splicing, fiber coupling and optical signal receiving technique were studied and a bionic compound eye receiving system was designed for staring laser radars. By imitating the structures and shapes of compound eyes of insects, the system consists of 16 lens arrays,and its whole field angle is 2 °. The optical system was designed by the Zemax software and optical signals were received by fiber coupling technology. The detection results were studied experimentally,and it shows that this receiving system can well reflect the contour of a detecting target,and the detection range is more than 200 m. On the experimental setup,a range image with 20 frames is obtained, and the pixel space is 1.72 m × 1.72 m. Obtained results verify the feasibility of proposed system and indicate that the system can be used in the missile end-guiding and the topographic matching of aerocrafts in low altitudes.%以生物视觉成像和目标识别为研究背景,深入研究了光学复眼的结构与拼接以及基于光纤耦合的光信号接收成像技术,并设计了一种可应用于凝视激光雷达的新型光学复眼接收系统.通过模仿昆虫复眼结构形式,该系统由16个透镜阵列构成,全视场角为2°.利用Zemax软件完成了光学系统设计,结合光纤耦合技术接收光信号,对复眼探测结果进行了实验研究和分析.结果表明,该接收系统能够准确地反映探测目标轮廓,探测距离可达200 m以上,在实验室获得了20 frame/s的距离图像,像点点阵间距为1.72 m×1.72 m.实验结果验证了该接收系统的合理性,表明该系统可以满足导弹末制导使用或是低空飞行器下视地形匹配.

  16. Efficient Compound-Cavity Eye-Safe KTP OPO at 1.57 μm Pumped by an Electro-Optic Q-Switched Nd: YAG Laser

    Institute of Scientific and Technical Information of China (English)

    ZHONG Kai; WANG Yu-Ye; XU De-Gang; GENG You-Fu; WANG Jing-Li; WANG Peng; YAO Jian-Quan

    2009-01-01

    An efficient high-energy eye-safe optical parametric oscillator (OPO) based on a type-Ⅱ non-critically phasematched KTP crystal is demonstrated.The KTP OPO is pumped by a quasi-cw diode side-pumped electrooptic Q-switched Nd:YAG laser in a compound-cavity configuration.The maximum output energy of the signal wavelength at 1.57 μm is 66.5 m J,corresponding to an electrical- to-optical conversion efficiency of 4.47% and an optical-to-optical conversion efficiency of 12.1%.The pulse width (FWHM) is about 3.6 ns with a peak power of 18.5 MW.The output energy is insensitive to repetition rate and demonstrates good stability.

  17. Creation of Coherent Superposition States in Multilevel Systems

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A powerful approach to generate multilevel superposition state in ∧-type manifold of levels is proposed. In the analysis, we introduce a group of rotations to transform the coupled system to a simpler form, which involves one coupled and several decoupled, dark states in the ground state manifold. Then an arbitrary superposition state of initial and final states can be created. In particular, when the Rabi frequencies of the Stokes pulses have equal magnitudes, a superposition state (equal population of the (n - 2) superposition states) will be generated. A numerical simulation of coherence generation is given. It is shown that a small transient population in metastable state decreases as the intensity of Stokes pulses increases. Experimental implementation in Neon atom is given.

  18. Nonclassical properties and quantum resources of hierarchical photonic superposition states

    Energy Technology Data Exchange (ETDEWEB)

    Volkoff, T. J., E-mail: adidasty@gmail.com [University of California, Department of Chemistry (United States)

    2015-11-15

    We motivate and introduce a class of “hierarchical” quantum superposition states of N coupled quantum oscillators. Unlike other well-known multimode photonic Schrödinger-cat states such as entangled coherent states, the hierarchical superposition states are characterized as two-branch superpositions of tensor products of single-mode Schrödinger-cat states. In addition to analyzing the photon statistics and quasiprobability distributions of prominent examples of these nonclassical states, we consider their usefulness for highprecision quantum metrology of nonlinear optical Hamiltonians and quantify their mode entanglement. We propose two methods for generating hierarchical superpositions in N = 2 coupled microwave cavities, exploiting currently existing quantum optical technology for generating entanglement between spatially separated electromagnetic field modes.

  19. On the Superposition and Elastic Recoil of Electromagnetic Waves

    CERN Document Server

    Schantz, Hans G

    2014-01-01

    Superposition demands that a linear combination of solutions to an electromagnetic problem also be a solution. This paper analyzes some very simple problems: the constructive and destructive interferences of short impulse voltage and current waves along an ideal free-space transmission line. When voltage waves constructively interfere, the superposition has twice the electrical energy of the individual waveforms because current goes to zero, converting magnetic to electrical energy. When voltage waves destructively interfere, the superposition has no electrical energy because it transforms to magnetic energy. Although the impedance of the individual waves is that of free space, a superposition of waves may exhibit arbitrary impedance. Further, interferences of identical waveforms allow no energy transfer between opposite ends of a transmission line. The waves appear to recoil elastically one from another. Although alternate interpretations are possible, these appear less likely. Similar phenomenology arises i...

  20. Quantum State Engineering Via Coherent-State Superpositions

    Science.gov (United States)

    Janszky, Jozsef; Adam, P.; Szabo, S.; Domokos, P.

    1996-01-01

    The quantum interference between the two parts of the optical Schrodinger-cat state makes possible to construct a wide class of quantum states via discrete superpositions of coherent states. Even a small number of coherent states can approximate the given quantum states at a high accuracy when the distance between the coherent states is optimized, e. g. nearly perfect Fock state can be constructed by discrete superpositions of n + 1 coherent states lying in the vicinity of the vacuum state.

  1. Healthy Eyes

    Science.gov (United States)

    ... los Ojos Cómo hablarle a su oculista Healthy Eyes Having a comprehensive dilated eye exam is one ... or contact lenses. What is a comprehensive dilated eye exam? A comprehensive dilated eye exam is a ...

  2. Testing the quantum superposition principle in the frequency domain

    CERN Document Server

    Bahrami, Mohammad; Ulbricht, Hendrik

    2013-01-01

    New technological developments allow to explore the quantum properties of very complex systems, bringing the question of whether also macroscopic systems share such features, within experimental reach. The interest in this question is increased by the fact that, on the theory side, many suggest that the quantum superposition principle is not exact, departures from it being the larger, the more macroscopic the system. Here we propose a novel way to test the possible violation of the superposition principle, by analyzing its effect on the spectral properties of a generic two-level system. We will show that spectral lines shapes are modified, if the superposition principle is violated, and we quantify the magnitude of the violation. We show how this effect can be distinguished from that of standard environmental noises. We argue that accurate enough spectroscopic experiments are within reach, with current technology.

  3. Dissipative Optomechanical Preparation of Macroscopic Quantum Superposition States

    Science.gov (United States)

    Abdi, M.; Degenfeld-Schonburg, P.; Sameti, M.; Navarrete-Benlloch, C.; Hartmann, M. J.

    2016-06-01

    The transition from quantum to classical physics remains an intensely debated question even though it has been investigated for more than a century. Further clarifications could be obtained by preparing macroscopic objects in spatial quantum superpositions and proposals for generating such states for nanomechanical devices either in a transient or a probabilistic fashion have been put forward. Here, we introduce a method to deterministically obtain spatial superpositions of arbitrary lifetime via dissipative state preparation. In our approach, we engineer a double-well potential for the motion of the mechanical element and drive it towards the ground state, which shows the desired spatial superposition, via optomechanical sideband cooling. We propose a specific implementation based on a superconducting circuit coupled to the mechanical motion of a lithium-decorated monolayer graphene sheet, introduce a method to verify the mechanical state by coupling it to a superconducting qubit, and discuss its prospects for testing collapse models for the quantum to classical transition.

  4. Quantum superposition counterintuitive consequences of coherence, entanglement, and interference

    CERN Document Server

    Silverman, M P

    2007-01-01

    Coherence, entanglement, and interference arise from quantum superposition, the most distinctive and puzzling feature of quantum physics. Silverman, whose extensive experimental and theoretical work has helped elucidate these processes, presents a clear and engaging discussion of the role of quantum superposition in diverse quantum phenomena such as the wavelike nature of particle propagation, indistinguishability of identical particles, nonlocal interactions of correlated particles, topological effects of magnetic fields, and chiral asymmetry in nature. He also examines how macroscopic quantum coherence may be able to extricate physics from its most challenging quandary, the collapse of a massive degenerate star to a singularity in space in which the laws of physics break down. Explained by a physicist with a concern for clarity and experimental achievability, the extraordinary nature of quantum superposition will fascinate the reader not only for its apparent strangeness, but also for its comprehensibility.

  5. Superposition of helical beams by using a Michelson interferometer.

    Science.gov (United States)

    Gao, Chunqing; Qi, Xiaoqing; Liu, Yidong; Weber, Horst

    2010-01-04

    Orbital angular momentum (OAM) of a helical beam is of great interests in the high density optical communication due to its infinite number of eigen-states. In this paper, an experimental setup is realized to the information encoding and decoding on the OAM eigen-states. A hologram designed by the iterative method is used to generate the helical beams, and a Michelson interferometer with two Porro prisms is used for the superposition of two helical beams. The experimental results of the collinear superposition of helical beams and their OAM eigen-states detection are presented.

  6. Pairwise Quantum Correlations for Superpositions of Dicke States

    Institute of Scientific and Technical Information of China (English)

    席政军; 熊恒娜; 李永明; 王晓光

    2012-01-01

    Pairwise correlation is really an important property for multi-qubit states.For the two-qubit X states extracted from Dicke states and their superposition states,we obtain a compact expression of the quantum discord by numerical check.We then apply the expression to discuss the quantum correlation of the reduced two-qubit states of Dicke states and their superpositions,and the results are compared with those obtained by entanglement of formation,which is a quantum entanglement measure.

  7. Superposition of nonlinear coherent states on a sphere

    Directory of Open Access Journals (Sweden)

    T Hosseinzadeh

    2013-09-01

    Full Text Available  In this paper, by using the nonlinear coherent states on a sphere, we introduce superposition of the aforementioned coherent states. Then, we consider quantum optical properties of these new superposed states and compare these properties with the corresponding properties of the nonlinear coherent states on the sphere. Specifically, we investigate their characteristics function, photon-number distribution, Mandel parameter, quadrature squeezing, anti-bunching effect and Wigner function, and obtain the curvature effect on the properties of the superposed states. Finally, by using the trapped atom system, we introduce a theoretical scheme to generate superposition of the coherent states on the sphere.

  8. 复眼立体的机器人视觉仿真%Compound Eye of Three - Dimensional Simulation of Robot Vision

    Institute of Scientific and Technical Information of China (English)

    张德忠; 贾正松

    2011-01-01

    Ordinary stereo for robot stereo vision camera simulation, this paper proposes a kind of compound eye stereo camera system. Through its principle analysis to identify the target depth of (he subject, location and the geometric relationship between cameras, the introduction of formula, given its visual simulation of the robot program. The system improves the accuracy of the robot visual simulation, applications feasible.%针对普通双目立体摄像机在机器人立体视觉仿真中的不足,提出一种复眼立体摄像系统.通过对其原理分析,找出被摄目标的深度、方位与摄像机之间的几何关系,推出计算公式,给出其在机器人视觉仿真中的应用方案.该系统提高了机器人视觉仿真精度,应用方案简单可行.

  9. The expression of three opsin genes from the compound eye of Helicoverpa armigera (Lepidoptera: Noctuidae is regulated by a circadian clock, light conditions and nutritional status.

    Directory of Open Access Journals (Sweden)

    Shuo Yan

    Full Text Available Visual genes may become inactive in species that inhabit poor light environments, and the function and regulation of opsin components in nocturnal moths are interesting topics. In this study, we cloned the ultraviolet (UV, blue (BL and long-wavelength-sensitive (LW opsin genes from the compound eye of the cotton bollworm and then measured their mRNA levels using quantitative real-time PCR. The mRNA levels fluctuated over a daily cycle, which might be an adaptation of a nocturnal lifestyle, and were dependent on a circadian clock. Cycling of opsin mRNA levels was disturbed by constant light or constant darkness, and the UV opsin gene was up-regulated after light exposure. Furthermore, the opsin genes tended to be down-regulated upon starvation. Thus, this study illustrates that opsin gene expression is determined by multiple endogenous and exogenous factors and is adapted to the need for nocturnal vision, suggesting that color vision may play an important role in the sensory ecology of nocturnal moths.

  10. Macroscopic superposition states and decoherence by quantum telegraph noise

    Energy Technology Data Exchange (ETDEWEB)

    Abel, Benjamin Simon

    2008-12-19

    In the first part of the present thesis we address the question about the size of superpositions of macroscopically distinct quantum states. We propose a measure for the ''size'' of a Schroedinger cat state, i.e. a quantum superposition of two many-body states with (supposedly) macroscopically distinct properties, by counting how many single-particle operations are needed to map one state onto the other. We apply our measure to a superconducting three-junction flux qubit put into a superposition of clockwise and counterclockwise circulating supercurrent states and find this Schroedinger cat to be surprisingly small. The unavoidable coupling of any quantum system to many environmental degrees of freedom leads to an irreversible loss of information about an initially prepared superposition of quantum states. This phenomenon, commonly referred to as decoherence or dephasing, is the subject of the second part of the thesis. We have studied the time evolution of the reduced density matrix of a two-level system (qubit) subject to quantum telegraph noise which is the major source of decoherence in Josephson charge qubits. We are able to derive an exact expression for the time evolution of the reduced density matrix. (orig.)

  11. Spectral properties of superpositions of Ornstein-Uhlenbeck type processes

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Leonenko, N.N.

    2005-01-01

    Stationary processes with prescribed one-dimensional marginal laws and long-range dependence are constructed. The asymptotic properties of the spectral densities are studied. The possibility of Mittag-Leffler decay in the autocorrelation function of superpositions of Ornstein-Uhlenbeck type proce...

  12. Generating superpositions of higher–order Bessel beams [Journal article

    CSIR Research Space (South Africa)

    Vasilyeu, R

    2009-12-01

    Full Text Available The authors report the first experimental generation of the superposition of higher-order Bessel beams, by means of a spatial light modulator (SLM) and a ring slit aperture. They present illuminating a ring slit aperture with light which has...

  13. The black hole information paradox and macroscopic superpositions

    CERN Document Server

    Hsu, Stephen D H

    2010-01-01

    We investigate the experimental capabilities required to test whether black holes destroy information. We show that an experiment capable of illuminating the information puzzle must necessarily be able to detect or manipulate macroscopic superpositions (i.e., Everett branches). Hence, it could also address the fundamental question of decoherence versus wavefunction collapse.

  14. Atomic quantum superposition state generation via optical probing

    DEFF Research Database (Denmark)

    Nielsen, Anne Ersbak Bang; Poulsen, Uffe Vestergaard; Negretti, Antonio

    2009-01-01

    We analyze the performance of a protocol to prepare an atomic ensemble in a superposition of two macroscopically distinguishable states. The protocol relies on conditional measurements performed on a light field, which interacts with the atoms inside an optical cavity prior to detection, and we...

  15. Eye Injuries

    Science.gov (United States)

    The structure of your face helps protect your eyes from injury. Still, injuries can damage your eye, sometimes severely enough that you could lose your vision. Most eye injuries are preventable. If you play sports or ...

  16. Eye Wear

    Science.gov (United States)

    Eye wear protects or corrects your vision. Examples are Sunglasses Safety goggles Glasses (also called eyeglasses) Contact ... jobs and some sports carry a risk of eye injury. Thousands of children and adults get eye ...

  17. Eye Cancer

    Science.gov (United States)

    Cancer of the eye is uncommon. It can affect the outer parts of the eye, such as the eyelid, which are made up ... adults are melanoma and lymphoma. The most common eye cancer in children is retinoblastoma, which starts in ...

  18. Eye Diseases

    Science.gov (United States)

    ... the back of the eye Macular degeneration - a disease that destroys sharp, central vision Diabetic eye problems ... defense is to have regular checkups, because eye diseases do not always have symptoms. Early detection and ...

  19. 盐酸环喷托酯滴眼液联合复方托吡卡胺滴眼液在学龄期儿童散瞳验光中的应用临床研究%combined application of Cyclopentolate hydrochloride drop eye fluid and Compound Tropicamide Eye Drops in school -age children in mydriatic optometry

    Institute of Scientific and Technical Information of China (English)

    洪茶花

    2014-01-01

    目的:观察盐酸环喷托酯滴眼液联合复方托吡卡胺滴眼液在学龄期儿童散瞳验光中的应用效果。方法60名学龄期儿童,120眼。每例先后用盐酸环喷托酯滴眼液联合复方托吡卡胺滴眼液及1%阿托品扩瞳验光取得验光数值,做自身对照。结果球镜结果相差≤0.25D的总计有115眼,占95.83%;球镜结果相差>0.25D总计有5眼,占4.17%。结论盐酸环喷托酯滴眼液联合复方托吡卡胺滴眼液用于学龄期儿童单纯近视或远视的散瞳效果好,可以替代阿托品,值得临床推广应用。%Objective To observe the ef ect of cyclopentolate hydrochloride eye drops combined with Compound Tropicamide Eye Drops in school-age children in the application ef ect of mydriasis optometry.Methods 60 school-age children,120 eyes.Each case has cyclopentolate hydrochloride eye drops combined with Compound Tropicamide Eye Drops and 1%atropine myd-riatic optometry .optometry values obtained,do their own control.Results the mirror bal result diference is less than 0.25D in 115 eyes,accounting for 95.83%;the mirror bal result difer-ence is >0.25D a total of 5 eyes,accounting for 4.17%.Conclusion cyclopentolate hydrochloride eye drops combined with Compound Tropicamide Eye Drops for school-age children simple myopia or hyperopia mydriatic ef ect is good,can replace atropine,worthy of clinical application.

  20. The Method for the Calibration and Measurement of Bionic Compound-eye System%仿生复眼系统标定及测量方法研究

    Institute of Scientific and Technical Information of China (English)

    张雄; 宋乐; 张姗姗; 房丰洲

    2014-01-01

    为了实现对近景目标物的三维测量,研制了一种小型仿生复眼系统。介绍了该复眼系统的结构及其参数设计原则,并对该系统采用的标定、三维测量等算法进行研究。首先根据复眼成像特点搭建了标定和测量平台,并分别使用张正友的方法、直接线性变换法、Tsai 式两步法三种摄像机标定方法对复眼的中心子眼进行标定,通过比较实验结果发现Tsai式标定方法精度更高,更适用于本复眼系统的标定。然后针对边缘子眼光轴与图像传感器不垂直问题,提出了一种新的图像畸变数学模型,有效的提高了边缘子眼的标定精度。最后建立了多子眼三维探测模型,并探索了多子眼成像对复眼相机测量精度的影响,认为三子眼可获得比双子眼更高的精度和稳定性。实验结果表明,在距离复眼相机150∼260 mm范围内,该复眼探测系统的三维测量相对误差在2%左右,在满足仪器小型化的同时能基本实现近景三维测量。%In order to realize close-range measurement, a miniaturized bionic compound-eye system was developed and the design principles of the system structure and parameters were introduced. Besides, the calibration and three-dimensional measurement algorithms were investigated. First, the platform for calibration and measurement was built based on imaging characteristics of the compound-eye. Three kinds of camera calibration methods, including Zhang’s method, the direct linear transformation method and Tsai two-step method, were carried out to calibrate the central sub-eye. By comparing the experimental results, it was determined that Tsai two-step method with high precision and accuracy was suitable for the calibration of the compound-eye system presented. Then, to solve the problem that the edge sub-vision axis was not perpendicular to the image sensor, a new distortion model that effectively improved the edge sub-eye

  1. Dynamical disappearance of superposition states in the thermodynamic limit

    CERN Document Server

    Frasca, M

    2003-01-01

    It is shown that a macroscopic superposition state of radiation, strongly interacting with an ensemble of two-level atoms, is removed generating a coherent state describing a classical radiation field, when the thermodynamic limit is taken on the unitary evolution obtained by the Schroedinger equation. Decoherence appears as a dynamical effect in agreement with a recent proposal [M. Frasca, Phys. Lett. A 283, 271 (2001)]. To prove that this effect is quite general, we show that this same behavior appears when a superposition of two Fock number states is also considered. Higher order corrections are computed showing that this result tends to become exact in the thermodynamic limit. It appears as a genuine example of intrinsic collapse of the wave function.

  2. Pairwise Quantum Correlations for Superpositions of Dicke States

    CERN Document Server

    Xi, Zhengjun; Li, Yongming; Wang, Xiaoguang

    2011-01-01

    Using the concept of quantum discord (QD), we study the quantum correlation for a class of two-qubit X states with exchange and parity symmetries, whose density matrices have complex off-diagonal elements. We derive an upper bound of the QD, which is independent of the arguments of the complex off-diagonal elements of the reduced two-qubit density matricies. Moreover, for the two-qubit X states obtained from Dicke states and their superposition states, we obtain a compact expression of the QD by numerical check. Finally, we apply the expression to discuss the quantum correlation of the reduced two-qubit states of Dicke states and their superpositions, and the results are compared with those obtained by entanglement of formation (EoF), which is a quantum entanglement measure.

  3. Experiments testing macroscopic quantum superpositions must be slow

    CERN Document Server

    Mari, Andrea; Giovannetti, Vittorio

    2015-01-01

    We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. We give a solution to the paradox which is based on the following fundamental principle: any local experiment, discriminating a coherent superposition from an incoherent statistical mixture, necessarily requires a minimum time proportional to the mass (or charge) of the system. For a charged particle, we consider two examples of such experiments, and show that they are both consistent with the previous limitation. In the first, the measurement requires to accelerate the charge, that can entangle with the emitted photons. In the second, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field. On the other hand, when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations an...

  4. Transforming spatial point processes into Poisson processes using random superposition

    DEFF Research Database (Denmark)

    Møller, Jesper; Berthelsen, Kasper Klitgaaard

    with a complementary spatial point process Y  to obtain a Poisson process X∪Y  with intensity function β. Underlying this is a bivariate spatial birth-death process (Xt,Yt) which converges towards the distribution of (X,Y). We study the joint distribution of X and Y, and their marginal and conditional distributions...... process with intensity function β if and only if the true Papangelou intensity is used. Whether the superposition is actually such a Poisson process can easily be examined using well known results and fast simulation procedures for Poisson processes. We illustrate this approach to model checking....... In particular, we introduce a fast and easy simulation procedure for Y conditional on X. This may be used for model checking: given a model for the Papangelou intensity of the original spatial point process, this model is used to generate the complementary process, and the resulting superposition is a Poisson...

  5. Superpositions of Lorentzians as the class of causal functions

    CERN Document Server

    Dirdal, Christopher A

    2013-01-01

    We prove that all functions obeying the Kramers-Kronig relations can be approximated as superpositions of Lorentzian functions, to any precision. As a result, the typical text-book analysis of dielectric dispersion response functions in terms of Lorentzians may be viewed as encompassing the whole class of causal functions under the conditions presented here. A further consequence is that Lorentzian resonances may be viewed as possible building blocks for engineering any desired metamaterial response. Two example functions, far from typical Lorentzian resonance behavior, are expressed in terms of Lorentzian superpositions: A steep dispersion medium that achieves large negative susceptibility with arbitrarily low loss/gain, and an optimal realization of a perfect lens over a bandwidth. Error bounds are derived for the approximation.

  6. Capacity-Approaching Superposition Coding for Optical Fiber Links

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Zibar, Darko; Tafur Monroy, Idelfonso

    2014-01-01

    We report on the first experimental demonstration of superposition coded modulation (SCM) for polarization-multiplexed coherent-detection optical fiber links. The proposed coded modulation scheme is combined with phase-shifted bit-to-symbol mapping (PSM) in order to achieve geometric and passive...... shaping of the signal's waveform. The output constellations in SCM-PSM exhibit nonbijective quasi-Gaussian statistical distributions that asymptotically reach the Shannon capacity limit, showing up to 0.7 dB sensitivity improvement for 256-ary SCM-PSM with respect to 256-ary quadrature amplitude...... modulation (QAM). The characteristic wave formation based on superposition of antipodal symbols and the lack of need for additional encoders for signal shaping, greatly reduces the transmitter and receiver processing complexity in comparison to conventional alternatives. Single-level coding strategy (SL-SCM...

  7. Measurement-Induced Macroscopic Superposition States in Cavity Optomechanics

    Science.gov (United States)

    Hoff, Ulrich B.; Kollath-Bönig, Johann; Neergaard-Nielsen, Jonas S.; Andersen, Ulrik L.

    2016-09-01

    A novel protocol for generating quantum superpositions of macroscopically distinct states of a bulk mechanical oscillator is proposed, compatible with existing optomechanical devices operating in the bad-cavity limit. By combining a pulsed optomechanical quantum nondemolition (QND) interaction with nonclassical optical resources and measurement-induced feedback, the need for strong single-photon coupling is avoided. We outline a three-pulse sequence of QND interactions encompassing squeezing-enhanced cooling by measurement, state preparation, and tomography.

  8. Single-Atom Gating of Quantum State Superpositions

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Christopher

    2010-04-28

    The ultimate miniaturization of electronic devices will likely require local and coherent control of single electronic wavefunctions. Wavefunctions exist within both physical real space and an abstract state space with a simple geometric interpretation: this state space - or Hilbert space - is spanned by mutually orthogonal state vectors corresponding to the quantized degrees of freedom of the real-space system. Measurement of superpositions is akin to accessing the direction of a vector in Hilbert space, determining an angle of rotation equivalent to quantum phase. Here we show that an individual atom inside a designed quantum corral1 can control this angle, producing arbitrary coherent superpositions of spatial quantum states. Using scanning tunnelling microscopy and nanostructures assembled atom-by-atom we demonstrate how single spins and quantum mirages can be harnessed to image the superposition of two electronic states. We also present a straightforward method to determine the atom path enacting phase rotations between any desired state vectors. A single atom thus becomes a real-space handle for an abstract Hilbert space, providing a simple technique for coherent quantum state manipulation at the spatial limit of condensed matter.

  9. Superposition dose calculation in lung for 10MV photons.

    Science.gov (United States)

    Hoban, P W; Murray, D C; Metcalfe, P E; Round, W H

    1990-06-01

    Currently available radiotherapy treatment planning systems employ scatter function models such as ETAR and Batho dSAR for dose calculation. Errors using these models for high energy photon irradiation occur in and beyond lung tissue for small fields. For larger fields, central axis dose is correctly predicted but penumbral broadening in lung is underestimated. The major source of error is the assumption that lateral electronic equilibrium is always established. A superposition algorithm has been developed for 10MV photons which calculates the dose by convolving the TERMA (Total Energy Released per unit MAss by primary photons) with a dose spread array formed using the EGS4 Monte Carlo code. TERMA and dose spread arrays are both generated using a 10 component photon energy spectrum. Dose in inhomogeneous media is calculated using dose spread arrays generated for different density media and by scaling dose spread arrays according to density variations. This method ensures that electronic disequilibrium is modelled in situations where it exists. Superposition results in a lung phantom for a 5 x 5 cm field agree with EGS4 Monte Carlo results to within 2% for p = 0.20 gcm-3 and p = 0.30 gcm-3 lung. Profiles generated by superposition for a 10 x 10 cm field at mid-lung and compared with film measurements show that penumbral broadening in low density material is also correctly predicted.

  10. Toward an Understanding of Divergent Compound Eye Development in Drones and Workers of the Honeybee (Apis mellifera L.): A Correlative Analysis of Morphology and Gene Expression.

    Science.gov (United States)

    Marco Antonio, David S; Hartfelder, Klaus

    2017-01-01

    Eye development in insects is best understood in Drosophila melanogaster, but little is known for other holometabolous insects. Combining a morphological with a gene expression analysis, we investigated eye development in the honeybee, putting emphasis on the sex-specific differences in eye size. Optic lobe development starts from an optic lobe anlage in the larval brain, which sequentially gives rise to the lobula, medulla, and lamina. The lamina differentiates in the last larval instar, when it receives optic nerve projections from the developing retina. The expression analysis focused on seven genes important for Drosophila eye development: eyes absent, sine oculis, embryonic lethal abnormal vision, minibrain, small optic lobes, epidermal growth factor receptor, and roughest. All except small optic lobes were more highly expressed in third-instar drone larvae, but then, in the fourth and fifth instar, their expression was sex-specifically modulated, showing shifts in temporal dynamics. The clearest differences were seen for small optic lobes, which is highly expressed in the developing eye of workers, and minibrain and roughest, which showed a strong expression peak coinciding with retina differentiation. A microarray analysis for optic lobe/retina complexes revealed the differential expression of several metabolism-related genes, as well as of two micro-RNAs. While we could not see major morphological differences in the developing eye structures before the pupal stage, the expression differences observed for the seven candidate genes and in the transcriptional microarray profiles indicate that molecular signatures underlying sex-specific optic lobe and retina development become established throughout the larval stages.

  11. Context-Based Questions: Optics in Animal Eyes

    Science.gov (United States)

    Kaltakci, Derya; Eryilmaz, Ali

    2011-01-01

    Context is important as a motivational factor for student involvement with physics. The diversity in the types and the functions of animal eyes is an excellent context in which to achieve this goal. There exists a range of subtopics in optics including pinhole, reflection, refraction, and superposition that can be discussed in the context of the…

  12. Eye Anatomy

    Science.gov (United States)

    ... News About Us Donate In This Section Eye Anatomy en Español email Send this article to a ... You at Risk For Glaucoma? Childhood Glaucoma Eye Anatomy Five Common Glaucoma Tests Glaucoma Facts and Stats ...

  13. Eye trauma

    African Journals Online (AJOL)

    2011-02-02

    Feb 2, 2011 ... will invariably lead to lid swelling, making the examination far more difficult. ... protect the eye with a pad or shield, give tetanus prophylaxis and refer. ... A study on penetrating eye injuries in South African children found.

  14. 双斑蟋复眼和视叶的显微结构%The fine structure of the compound eye and optic lobe of the two-spotted cricketGryllus bimaculatus

    Institute of Scientific and Technical Information of China (English)

    那宇鹏; 冷雪; 那杰

    2015-01-01

    Objectives] To investigate the important neural structures of insect visual signal processing by observing and describing the histological structural features of the compound eyesand optic lobesof the cricket (Orthoptera: Gryllidae). [Methods] The histological structure of the compound eye and optic lobe of 30 crickets was observed and analyzed using scanning electron microscopy and histological biopsy techniques.[Results] The compound eye was comprised of about 3 400 small hexagonal eyes. In the gaps between the small eyes, there are mechanoreceptors, which are sensory hair and bell-shaped receptors. Each small eye is comprised of a cornea, crystalline cone, rhabdome, 6 retinal cells and basement membrane, etc. The optic lobe has two fan-shaped structures and is comprised of three major networks of nerve fibers, the ganglion layer, outer medulla and inner medulla.[Conclusion] There are a few sensory hairs and bell-shaped receptors on the surface of the compound eyes of crickets. Each small eye is comprised of a cornea, crystalline cone, rhabdome, 6 retinal cells, basement membrane, etc. and the arrangement of small eyes is juxtaposed. The optic lobe is comprised of three major networks of nerve fibers.%【目的】为探索昆虫视觉信号处理的重要神经结构,详细观察和描述了直翅目(Orthoptera)蟋蟀科(Gryllidae)代表性昆虫双斑蟋Gryllus bimaculatus De Geer复眼和视叶的组织学结构特征。【方法】利用扫描电镜技术和组织学切片技术,观察分析了30只双斑蟋的复眼和视叶组织学结构。【结果】双斑蟋复眼约有3400个小眼,均为六边形结构,小眼间隙内分布有机械感受器——感觉毛和钟形感受器。每个小眼均由角膜、晶锥、感杆束、6个网膜细胞及基膜等构成。视叶呈两个扇形结构,由三大神经纤维网构成,分别为神经节层、外髓、内髓。【结论】双斑蟋复眼表面具有少量感觉毛和钟形感受器,每个

  15. Concentration-temperature superposition of helix folding rates in gelatin.

    Science.gov (United States)

    Gornall, J L; Terentjev, E M

    2007-07-13

    Using optical rotation as the primary technique, we have characterized the kinetics of helix renaturation in water solutions of gelatin. By covering a wide range of solution concentrations we identify a universal exponential dependence of folding rate on concentration and quench temperature. We demonstrate a new concentration-temperature superposition of data at all temperatures and concentrations, and build the corresponding master curve. The normalized rate constant is consistent with helix lengthening. Nucleation of the triple helix occurs rapidly and contributes less to the helical onset than previously thought.

  16. Construction of quantum states by special superpositions of coherent states

    Science.gov (United States)

    Adam, P.; Molnar, E.; Mogyorosi, G.; Varga, A.; Mechler, M.; Janszky, J.

    2015-06-01

    We consider the optimal approximation of certain quantum states of a harmonic oscillator with the superposition of a finite number of coherent states in phase space placed either on an ellipse or on a certain lattice. These scenarios are currently experimentally feasible. The parameters of the ellipse and the lattice and the coefficients of the constituent coherent states are optimized numerically, via a genetic algorithm, in order to obtain the best approximation. It is found that for certain quantum states the obtained approximation is better than the ones known from the literature thus far.

  17. Seeing lens imaging as a superposition of multiple views

    CERN Document Server

    Grusche, Sascha

    2015-01-01

    In the conventional approach to lens imaging, rays are used to map object points to image points. However, many students have a need to think of the image as a whole. To answer this need, lens imaging is reinterpreted as a superposition of sharp images from different viewpoints. These so-called elemental images are uncovered by covering the lens with a pinhole array. Rays are introduced to connect elemental images. Lens ray diagrams are constructed based on bundles of elemental images. The conventional construction method is included as a special case. The proposed approach proceeds from concrete images to abstract rays.

  18. Coherent control of mesoscopic superpositions in a diatomic molecule

    CERN Document Server

    Ghosh, Suranjana

    2011-01-01

    A phase controlled wave packet, recently used in experiment of wave packet interferometry of a diatomic molecule, is investigated to obtain mesoscopic superposition structures, useful in quantum metrology. This analysis provides a new way of obtaining sub-Planck scale structures at smaller time scale of revival dynamics. We study a number of situations for delineating the smallest interference structures and their control by tailoring the relative phase between two subsidiary wave packets. We also find the most appropriate state, so far, for high precision parameter estimation in a system of diatomic molecule.

  19. Efficient Power Allocation for Video over Superposition Coding

    KAUST Repository

    Lau, Chun Pong

    2013-03-01

    In this paper we consider a wireless multimedia system by mapping scalable video coded (SVC) bit stream upon superposition coded (SPC) signals, referred to as (SVC-SPC) architecture. Empirical experiments using a software-defined radio(SDR) emulator are conducted to gain a better understanding of its efficiency, specifically, the impact of the received signal due to different power allocation ratios. Our experimental results show that to maintain high video quality, the power allocated to the base layer should be approximately four times higher than the power allocated to the enhancement layer.

  20. Measurement-induced macroscopic superposition states in cavity optomechanics

    CERN Document Server

    Hoff, Ulrich B; Neergaard-Nielsen, Jonas S; Andersen, Ulrik L

    2016-01-01

    We present a novel proposal for generating quantum superpositions of macroscopically distinct states of a bulk mechanical oscillator, compatible with existing optomechanical devices operating in the readily achievable bad-cavity limit. The scheme is based on a pulsed cavity optomechanical quantum non-demolition (QND) interaction, driven by displaced non-Gaussian states, and measurement-induced feedback, avoiding the need for strong single-photon optomechanical coupling. Furthermore, we show that single-quadrature cooling of the mechanical oscillator is sufficient for efficient state preparation, and we outline a three-pulse protocol comprising a sequence of QND interactions for squeezing-enhanced cooling, state preparation, and tomography.

  1. On Kolmogorov's superpositions and Boolean functions

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.

    1998-12-31

    The paper overviews results dealing with the approximation capabilities of neural networks, as well as bounds on the size of threshold gate circuits. Based on an explicit numerical (i.e., constructive) algorithm for Kolmogorov's superpositions they will show that for obtaining minimum size neutral networks for implementing any Boolean function, the activation function of the neurons is the identity function. Because classical AND-OR implementations, as well as threshold gate implementations require exponential size (in the worst case), it will follow that size-optimal solutions for implementing arbitrary Boolean functions require analog circuitry. Conclusions and several comments on the required precision are ending the paper.

  2. Quantum teleportation of one- and two-photon superposition states

    Institute of Scientific and Technical Information of China (English)

    李英; 张天才; 张俊香; 谢常德

    2003-01-01

    Quantum teleportation of one- and two-photon superposition states based on EPR entanglement of continuouswave two-mode squeezed state is discussed. The fidelities of teleportation are deduced for two different input quantum states. The dependence of the fidelity on the parameters of EPR entanglement and the gain of the classical channels are shown numerically. Comparing with the teleportation of Fock state and coherent state, it is pointed out that for given EPR entanglement and classical gain, the higher the nonclassicality of the input state, the lower the accessible fidelity of teleportation.

  3. Fabrication of Compound Eye Structures on Silicon by Direct Three-Beam Laser Interference Lithography%三光束激光干涉光刻法制备生物复眼表面微结构

    Institute of Scientific and Technical Information of China (English)

    关会英; 司玉兰; 曹亮; 梁志海

    2015-01-01

    Many excellent performance such as a large field of view,high time resolution,high reflectivity, superhydrophobicity and antifogging properties were found on biological compound eye surfaces continuously. Bionics research shows,the microstructure of compound eye surfaces play a key role in realizing specific function. In this paper,the artificial Ephemera pictiventris McLachlan compound eyes was fabricated via laser lithography technology( LIL)based on three-beam interference on a silicon substrate,and the influence of laser energy and exposure time on the surface morphology was discussed. The results show that laser energy is 40 mJ and the exposure time is 15 s are optimal laser processing parameters for the 20μm feature size.%许多生物复眼表面具有大视场、高时间分辨率、高反射率以及超疏水、防雾等优异性能,工程应用潜力巨大。仿生学研究表明,复眼表面微观结构对其特定功能的实现具有关键作用。本文利用三光束激光干涉光刻技术在单晶硅基底表面制备了仿腹色蜉复眼表面微结构,并讨论了激光能量及曝光时间对加工表面形貌的影响,从而获得了20μm特征尺寸下最优激光加工工艺参数为激光能量为40 mJ,曝光时间为15 s为最优试验条件。

  4. Image reconstruction algorithm inspired by a bionic compound eye system%受昆虫复眼系统启发的图像重构算法

    Institute of Scientific and Technical Information of China (English)

    李敏; 徐立中; 石爱业; 黄凤辰

    2009-01-01

    虽然基于像素重排列的迭代反投影算法已经在TOMBO模型构建时提出,但是该方法需要大量的迭代次数,同时在噪声平滑效果上还有待于改进.因此一种正则化的迭代反投影算法被提出为该系统重构图像.采用自适应的总变差正则化因子和双边总变差正则化因子来正则化迭代反投影算法.自适应总变差正则化因子根据图像的当前信息来选择参数,因此用该因子正则化后的迭代反投影算法可以在平滑噪声的同时保留高频成分.而双边总变差正则化因子是依据像素点的最邻近领域和次邻近领域来判别该点是否为噪声点,考虑了更多的图像信息,从而可以跨过边缘平滑噪声.同时双边总变差正则化因子可以大大地加速重构的过程.实验是建立在仿生复眼图像上,实验结果证明了这两种正则化的迭代算法的有效性.%Iterative back-projection algorithms based on pixel-rearrangement have been reported since thin observation modules using bound optical(TOMBO) systems were presented. However computational costs are high and the noise smoothing ability needs to be improved. So a normalized iterative back-projection algorithm was proposed to get reconstructed images for this system. Both an adaptive total variation normalized factor and a bilateral total variation normalized factor were employed to normalize the iterative back-projection algorithm. The former factor chose parameters adaptively according to present image information, so it could retrieve the high frequency components while smoothing noise. However, the latter factor determined the noise points according to nearest and next nearest neighborhood of pixels, in which more image information was considered so that it smoothed noises across boundaries. Also the latter factor accelerated the reconstructing process greatly. Experiments were based on bionic compound eye images. And the results demonstrated that the suggested

  5. Runs in superpositions of renewal processes with applications to discrimination

    Science.gov (United States)

    Alsmeyer, Gerold; Irle, Albrecht

    2006-02-01

    Wald and Wolfowitz [Ann. Math. Statist. 11 (1940) 147-162] introduced the run test for testing whether two samples of i.i.d. random variables follow the same distribution. Here a run means a consecutive subsequence of maximal length from only one of the two samples. In this paper we contribute to the problem of runs and resulting test procedures for the superposition of independent renewal processes which may be interpreted as arrival processes of customers from two different input channels at the same service station. To be more precise, let (Sn)n[greater-or-equal, slanted]1 and (Tn)n[greater-or-equal, slanted]1 be the arrival processes for channel 1 and channel 2, respectively, and (Wn)n[greater-or-equal, slanted]1 their be superposition with counting process . Let further be the number of runs in W1,...,Wn and the number of runs observed up to time t. We study the asymptotic behavior of and Rt, first for the case where (Sn)n[greater-or-equal, slanted]1 and (Tn)n[greater-or-equal, slanted]1 have exponentially distributed increments with parameters [lambda]1 and [lambda]2, and then for the more difficult situation when these increments have an absolutely continuous distribution. These results are used to design asymptotic level [alpha] tests for testing [lambda]1=[lambda]2 against [lambda]1[not equal to][lambda]2 in the first case, and for testing for equal scale parameters in the second.

  6. Outage probability analysis for superposition coded symmetric relaying

    Institute of Scientific and Technical Information of China (English)

    WU Yi; ZHENG Meng; FEI ZeSong; LARSSON Erik G.; KUANG JingMing

    2013-01-01

    Superposition coded symmetric relaying is a bandwidth-efficient cooperative scheme where each source node simultaneously transmits both its own "local" packet and "relay" packet that originated at its partner by adding the modulated local and relay signals in Euclidean space. This paper investigates the power allocation and outage probability of a superposition coded symmetric relaying system with finite-constellation signaling. We first derive the mutual information (MI) metrics for the system. The derived MI metrics consist of two parts: one represents the MI conveyed by the modulated signal corresponding to its own data, and the other represents the MI conveyed by the modulated signal corresponding to its partner's data. Using MI based effective signal-to-noise ratio mapping technique, we attain expressions for the outage probability. Furthermore, we discuss power allocation policies that minimize the outage probability. Simulation results are presented to verify the correctness of the outage probability analysis and the benefits of the power allocation.

  7. Superposition states for quantum nanoelectronic circuits and their nonclassical properties

    Science.gov (United States)

    Choi, Jeong Ryeol

    2016-09-01

    Quantum properties of a superposition state for a series RLC nanoelectronic circuit are investigated. Two displaced number states of the same amplitude but with opposite phases are considered as components of the superposition state. We have assumed that the capacitance of the system varies with time and a time-dependent power source is exerted on the system. The effects of displacement and a sinusoidal power source on the characteristics of the state are addressed in detail. Depending on the magnitude of the sinusoidal power source, the wave packets that propagate in charge(q)-space are more or less distorted. Provided that the displacement is sufficiently high, distinct interference structures appear in the plot of the time behavior of the probability density whenever the two components of the wave packet meet together. This is strong evidence for the advent of nonclassical properties in the system, that cannot be interpretable by the classical theory. Nonclassicality of a quantum system is not only a beneficial topic for academic interest in itself, but its results can be useful resources for quantum information and computation as well.

  8. Experiments testing macroscopic quantum superpositions must be slow

    Science.gov (United States)

    Mari, Andrea; de Palma, Giacomo; Giovannetti, Vittorio

    2016-03-01

    We consider a thought experiment where the preparation of a macroscopically massive or charged particle in a quantum superposition and the associated dynamics of a distant test particle apparently allow for superluminal communication. We give a solution to the paradox which is based on the following fundamental principle: any local experiment, discriminating a coherent superposition from an incoherent statistical mixture, necessarily requires a minimum time proportional to the mass (or charge) of the system. For a charged particle, we consider two examples of such experiments, and show that they are both consistent with the previous limitation. In the first, the measurement requires to accelerate the charge, that can entangle with the emitted photons. In the second, the limitation can be ascribed to the quantum vacuum fluctuations of the electromagnetic field. On the other hand, when applied to massive particles our result provides an indirect evidence for the existence of gravitational vacuum fluctuations and for the possibility of entangling a particle with quantum gravitational radiation.

  9. Unveiling the curtain of superposition: Recent gedanken and laboratory experiments

    Science.gov (United States)

    Cohen, E.; Elitzur, A. C.

    2017-08-01

    What is the true meaning of quantum superposition? Can a particle genuinely reside in several places simultaneously? These questions lie at the heart of this paper which presents an updated survey of some important stages in the evolution of the three-boxes paradox, as well as novel conclusions drawn from it. We begin with the original thought experiment of Aharonov and Vaidman, and proceed to its non-counterfactual version. The latter was recently realized by Okamoto and Takeuchi using a quantum router. We then outline a dynamic version of this experiment, where a particle is shown to “disappear” and “re-appear” during the time evolution of the system. This surprising prediction based on self-cancellation of weak values is directly related to our notion of Quantum Oblivion. Finally, we present the non-counterfactual version of this disappearing-reappearing experiment. Within the near future, this last version of the experiment is likely to be realized in the lab, proving the existence of exotic hitherto unknown forms of superposition. With the aid of Bell’s theorem, we prove the inherent nonlocality and nontemporality underlying such pre- and post-selected systems, rendering anomalous weak values ontologically real.

  10. Modelling polychromatic high energy photon beams by superposition.

    Science.gov (United States)

    Metcalfe, P E; Hoban, P W; Murray, D C; Round, W H

    1989-09-01

    A unified three dimensional superposition approach to dose calculations used in treatment planning of polychromatic high energy photon beams in radiotherapy is developed. The approach we have used involves computing the dose at all points in a medium by superposing the dose spread array (DSA) from the interaction of a photon at a point in the medium with an array of data representing the TERMA (photon fluence times the photon energy) at points in the beam. The polychromatic nature of the beam is accounted for by modelling the beam as having ten spectral components. A "polychromatic dose spread array" (PDSA) for an interaction from a beam with this spectrum was derived. The TERMA array is calculated from a weighted average of the TERMA arrays for the ten photon energies to give a "polychromatic TERMA array". Thus the method accounts for the effect of beam hardening of the TERMA. But it does not account for the effect of beam hardening on the PDSA since a single PDSA (usually for the spectrum at the surface of the medium) is used at all depths. However, by considering measured and calculated beam central axis data, this model is shown to be adequate for computing depth doses for beams in a homogeneous medium penetrating to extreme radiological depths. A computation time advantage is gained because only one superposition per beam is required.

  11. Free Nano-Object Ramsey Interferometry for Large Quantum Superpositions

    Science.gov (United States)

    Wan, C.; Scala, M.; Morley, G. W.; Rahman, ATM. A.; Ulbricht, H.; Bateman, J.; Barker, P. F.; Bose, S.; Kim, M. S.

    2016-09-01

    We propose an interferometric scheme based on an untrapped nano-object subjected to gravity. The motion of the center of mass (c.m.) of the free object is coupled to its internal spin system magnetically, and a free flight scheme is developed based on coherent spin control. The wave packet of the test object, under a spin-dependent force, may then be delocalized to a macroscopic scale. A gravity induced dynamical phase (accrued solely on the spin state, and measured through a Ramsey scheme) is used to reveal the above spatially delocalized superposition of the spin-nano-object composite system that arises during our scheme. We find a remarkable immunity to the motional noise in the c.m. (initially in a thermal state with moderate cooling), and also a dynamical decoupling nature of the scheme itself. Together they secure a high visibility of the resulting Ramsey fringes. The mass independence of our scheme makes it viable for a nano-object selected from an ensemble with a high mass variability. Given these advantages, a quantum superposition with a 100 nm spatial separation for a massive object of 1 09 amu is achievable experimentally, providing a route to test postulated modifications of quantum theory such as continuous spontaneous localization.

  12. Student ability to distinguish between superposition states and mixed states in quantum mechanics

    Science.gov (United States)

    Passante, Gina; Emigh, Paul J.; Shaffer, Peter S.

    2015-12-01

    Superposition gives rise to the probabilistic nature of quantum mechanics and is therefore one of the concepts at the heart of quantum mechanics. Although we have found that many students can successfully use the idea of superposition to calculate the probabilities of different measurement outcomes, they are often unable to identify the experimental implications of a superposition state. In particular, they fail to recognize how a superposition state and a mixed state (sometimes called a "lack of knowledge" state) can produce different experimental results. We present data that suggest that superposition in quantum mechanics is a difficult concept for students enrolled in sophomore-, junior-, and graduate-level quantum mechanics courses. We illustrate how an interactive lecture tutorial can improve student understanding of quantum mechanical superposition. A longitudinal study suggests that the impact persists after an additional quarter of quantum mechanics instruction that does not specifically address these ideas.

  13. Role of the superposition principle for enhancing the efficiency of the quantum-mechanical Carnot engine.

    Science.gov (United States)

    Abe, Sumiyoshi; Okuyama, Shinji

    2012-01-01

    The role of the superposition principle is discussed for the quantum-mechanical Carnot engine introduced by Bender, Brody, and Meister [J. Phys. A 33, 4427 (2000)]. It is shown that the efficiency of the engine can be enhanced by the superposition of quantum states. A finite-time process is also discussed and the condition of the maximum power output is presented. Interestingly, the efficiency at the maximum power is lower than that without superposition.

  14. Vibration Superposition in Tunnel Blasting with Millisecond Delay

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jun-jie; LOU Xiao-ming; LUO De-pi

    2009-01-01

    According to explosion dynamics and elastic wave theory,the models of particle vibration velocity for simultaneous blasting and millisecond blasting are built.In the models,influential factors such as delay interval and charge quantity,are considered.The calculated vibration velocity is compared with the field test results,which shows that the theoretical values are close to the experimental ones.Meanwhile,the particle vibration velocity decreases quickly with time due to the damping of rock mass and has a harmonic motion,and the particle vibration velocity of millisecond blasting has short interval.The superposition of particle vibration velocities may reduce vibration because of wave interference,or magnify the surrounding rock response to the blasting-induced vibration.

  15. Quantum Decoherence Timescales for Ionic Superposition States in Ion Channels

    CERN Document Server

    Salari, V; Fazileh, F; Shahbazi, F

    2014-01-01

    There are many controversial and challenging discussions about quantum effects in microscopic structures in neurons of the human brain. The challenge is mainly because of quick decoherence of quantum states due to hot, wet and noisy environment of the brain which forbids long life coherence for brain processing. Despite these critical discussions, there are only a few number of published papers about numerical aspects of decoherence in neurons. Perhaps the most important issue is offered by Max Tegmark who has calculated decoherence times for the systems of "ions" and "microtubules" in neurons of the brain. In fact, Tegmark did not consider ion channels which are responsible for ions displacement through the membrane and are the building blocks of electrical membrane signals in the nervous system. Here, we would like to re-investigate decoherence times for ionic superposition states by using the data obtained via molecular dynamics simulations. Our main approach is according to what Tegmark has used before. I...

  16. Adiabatic rotation, quantum search, and preparation of superposition states

    Science.gov (United States)

    Siu, M. Stewart

    2007-06-01

    We introduce the idea of using adiabatic rotation to generate superpositions of a large class of quantum states. For quantum computing this is an interesting alternative to the well-studied “straight line” adiabatic evolution. In ways that complement recent results, we show how to efficiently prepare three types of states: Kitaev’s toric code state, the cluster state of the measurement-based computation model, and the history state used in the adiabatic simulation of a quantum circuit. We also show that the method, when adapted for quantum search, provides quadratic speedup as other optimal methods do with the advantages that the problem Hamiltonian is time independent and that the energy gap above the ground state is strictly nondecreasing with time. Likewise the method can be used for optimization as an alternative to the standard adiabatic algorithm.

  17. Sensing Super-Position: Human Sensing Beyond the Visual Spectrum

    Science.gov (United States)

    Maluf, David A.; Schipper, John F.

    2007-01-01

    The coming decade of fast, cheap and miniaturized electronics and sensory devices opens new pathways for the development of sophisticated equipment to overcome limitations of the human senses. This paper addresses the technical feasibility of augmenting human vision through Sensing Super-position by mixing natural Human sensing. The current implementation of the device translates visual and other passive or active sensory instruments into sounds, which become relevant when the visual resolution is insufficient for very difficult and particular sensing tasks. A successful Sensing Super-position meets many human and pilot vehicle system requirements. The system can be further developed into cheap, portable, and low power taking into account the limited capabilities of the human user as well as the typical characteristics of his dynamic environment. The system operates in real time, giving the desired information for the particular augmented sensing tasks. The Sensing Super-position device increases the image resolution perception and is obtained via an auditory representation as well as the visual representation. Auditory mapping is performed to distribute an image in time. The three-dimensional spatial brightness and multi-spectral maps of a sensed image are processed using real-time image processing techniques (e.g. histogram normalization) and transformed into a two-dimensional map of an audio signal as a function of frequency and time. This paper details the approach of developing Sensing Super-position systems as a way to augment the human vision system by exploiting the capabilities of Lie human hearing system as an additional neural input. The human hearing system is capable of learning to process and interpret extremely complicated and rapidly changing auditory patterns. The known capabilities of the human hearing system to learn and understand complicated auditory patterns provided the basic motivation for developing an image-to-sound mapping system. The

  18. Predicting jet radius in electrospinning by superpositioning exponential functions

    Science.gov (United States)

    Widartiningsih, P. M.; Iskandar, F.; Munir, M. M.; Viridi, S.

    2016-08-01

    This paper presents an analytical study of the correlation between viscosity and fiber diameter in electrospinning. Control over fiber diameter in electrospinning process was important since it will determine the performance of resulting nanofiber. Theoretically, fiber diameter was determined by surface tension, solution concentration, flow rate, and electric current. But experimentally it had been proven that significantly viscosity had an influence to fiber diameter. Jet radius equation in electrospinning process was divided into three areas: near the nozzle, far from the nozzle, and at jet terminal. There was no correlation between these equations. Superposition of exponential series model provides the equations combined into one, thus the entire of working parameters on electrospinning take a contribution to fiber diameter. This method yields the value of solution viscosity has a linear relation to jet radius. However, this method works only for low viscosity.

  19. Performance of Superposition Coded Broadcast/Unicast Service Overlay System

    Science.gov (United States)

    Yoon, Seokhyun; Kim, Donghee

    The system level performance of a superposition coded broadcast/unicast service overlay system is considered. Cellular network for unicast service only is considered as interference limited system, where increasing the transmission power does not help improve the network throughput especially when the frequency reuse factor is close to 1. In such cases, the amount of power that does not contribute to improving the throughput can be considered as “unused.” This situation motivates us to use the unused power for broadcast services, which can be efficiently provided in OFDM based single frequency networks as in digital multimedia broadcast systems. In this paper, we investigate the performance of such a broadcast/unicast overlay system in which a single frequency broadcast service is superimposed over a unicast cellular service. Alternative service multiplexing using FDM/TDM is also considered for comparison.

  20. Macroscopicity of quantum superpositions on a one-parameter unitary path in Hilbert space

    Science.gov (United States)

    Volkoff, T. J.; Whaley, K. B.

    2014-12-01

    We analyze quantum states formed as superpositions of an initial pure product state and its image under local unitary evolution, using two measurement-based measures of superposition size: one based on the optimal quantum binary distinguishability of the branches of the superposition and another based on the ratio of the maximal quantum Fisher information of the superposition to that of its branches, i.e., the relative metrological usefulness of the superposition. A general formula for the effective sizes of these states according to the branch-distinguishability measure is obtained and applied to superposition states of N quantum harmonic oscillators composed of Gaussian branches. Considering optimal distinguishability of pure states on a time-evolution path leads naturally to a notion of distinguishability time that generalizes the well-known orthogonalization times of Mandelstam and Tamm and Margolus and Levitin. We further show that the distinguishability time provides a compact operational expression for the superposition size measure based on the relative quantum Fisher information. By restricting the maximization procedure in the definition of this measure to an appropriate algebra of observables, we show that the superposition size of, e.g., NOON states and hierarchical cat states, can scale linearly with the number of elementary particles comprising the superposition state, implying precision scaling inversely with the total number of photons when these states are employed as probes in quantum parameter estimation of a 1-local Hamiltonian in this algebra.

  1. The number of terms in the superpositions upper bounds the amount of the coherence change

    Science.gov (United States)

    Liu, Feng; Li, Fei

    2016-10-01

    For the l1 norm of coherence, what is the relation between the coherence of a state and the individual terms that by superposition yield the state? We find upper bounds on the coherence change before and after the superposition. When every term comes from one Hilbert subspace, the upper bound is the number of terms in the superpositions minus one. However, when the terms have support on orthogonal subspaces, the coherence of the superposition cannot be more the double of the above upper bound than the average of the coherence of the all terms being superposed.

  2. On first-order theorem proving using generalized odd-superpositions

    Institute of Scientific and Technical Information of China (English)

    吴尽昭; 刘卓军

    1996-01-01

    It is shown that the proof system using odd-superpositions Ⅱ is not complete.The reason leading to this incompleteness is that the use of idempotency rule is neglected.By defining the superpositions of first-order polynomials and zero,the concept of odd-superpositions Ⅱ is extended,and a complete proof system using the extended odd-superpositions Ⅱ is developed.In addition,this proof system is an improvement on remainder method;its completeness demonstrates actually that the remainder method using semantic strategy is still complete.

  3. Diabetes eye exams

    Science.gov (United States)

    Diabetic retinopathy - eye exams; Diabetes - eye exams; Glaucoma - diabetic eye exam; Macular edema - diabetic eye exam ... if the doctor who takes care of your diabetes checks your eyes, you need an eye exam ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: ... your eyes do not produce enough tears, it is called dry eye. Dry eye is also when ...

  5. Facts About Pink Eye

    Science.gov (United States)

    ... Information > Pink Eye (Conjunctivitis) > Facts About Pink Eye Facts About Pink Eye Pink eye is one of ... for preventing eye infections. Last Reviewed: November 2015 Fact Sheet Blurb The National Eye Institute (NEI) is ...

  6. Dilating Eye Drops

    Science.gov (United States)

    ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ... Corneal Abrasions Dilating Eye Drops Lazy eye (defined) Pink eye (defined) Retinopathy of Prematurity Strabismus Stye (defined) Vision ...

  7. Your Eyes

    Science.gov (United States)

    ... eyes to see millions of colors. Helping You See It All Rods and cones process the light to give you the total picture. You're ... get cloudy, causing a cataract . A cataract prevents light from reaching the retina and makes it difficult to see. The eyes you have will be yours forever — ...

  8. Eyes - bulging

    Science.gov (United States)

    ... emotional support is important. When to Contact a Medical Professional Call your health care provider if: You have bulging eyes and the cause has not yet been diagnosed. Bulging eyes are accompanied by other symptoms. ... The provider will ask about your medical history and do a physical exam. Some questions ...

  9. Creation of nano eye-drops and effective drug delivery to the interior of the eye

    Science.gov (United States)

    Ikuta, Yoshikazu; Aoyagi, Shigenobu; Tanaka, Yuji; Sato, Kota; Inada, Satoshi; Koseki, Yoshitaka; Onodera, Tsunenobu; Oikawa, Hidetoshi; Kasai, Hitoshi

    2017-03-01

    Nano eye-drops are a new type of ophthalmic treatment with increased potency and reduced side effects. Compounds in conventional eye-drops barely penetrate into the eye because the cornea, located at the surface of eye, has a strong barrier function for preventing invasion of hydrophilic or large-sized materials from the outside. In this work, we describe the utility of nano eye-drops utilising brinzolamide, a commercially available glaucoma treatment drug, as a target compound. Fabrication of the nanoparticles of brinzolamide prodrug increases the eye penetration rate and results in high drug efficacy, compared with that of commercially available brinzolamide eye-drops formulated as micro-sized structures. In addition, the resulting nano eye-drops were not toxic to the corneal epithelium after repeated administration for 1 week. The nano eye-drops may have applications as a next-generation ophthalmic treatment.

  10. Generation of superpositions of coherent states for an atomic sample in cavity QED

    Institute of Scientific and Technical Information of China (English)

    Zheng Shi-Biao

    2009-01-01

    This paper proposes a scheme for generation of superpositions of coherent states of the effective bosonic mode in a collection of atoms. In the scheme an atomic sample interacts with a slightly detuned cavity mode and a resonant strong classical field. Under certain conditions the atomic system evolves from a coherent state to a superposition of coherent states.

  11. Superposition Principle and Young Type Double-Slit Experiment in Vacuum

    CERN Document Server

    Savas, A

    2002-01-01

    In this study, it is shown with reasons that superposition principle does not work in vacuum. This case can be observed by Young type double slit experiment to be carried out. Since field-field interaction is carried through charged particles, in the absence of charged particles linear superposition of two fields is not possible and interference will not be observed.

  12. A note on superposition of two unknown states using Deutsch CTC model

    CERN Document Server

    Sami, Sasha

    2016-01-01

    In a recent work, authors prove a yet another no-go theorem that forbids the existence of a universal probabilistic quantum protocol producing a superposition of two unknown quantum states. In this short note, we show that in the presence of closed time like curves, one can indeed create superposition of unknown quantum states and evade the no-go result.

  13. Student Ability to Distinguish between Superposition States and Mixed States in Quantum Mechanics

    Science.gov (United States)

    Passante, Gina; Emigh, Paul J.; Shaffer, Peter S.

    2015-01-01

    Superposition gives rise to the probabilistic nature of quantum mechanics and is therefore one of the concepts at the heart of quantum mechanics. Although we have found that many students can successfully use the idea of superposition to calculate the probabilities of different measurement outcomes, they are often unable to identify the…

  14. Student Ability to Distinguish between Superposition States and Mixed States in Quantum Mechanics

    Science.gov (United States)

    Passante, Gina; Emigh, Paul J.; Shaffer, Peter S.

    2015-01-01

    Superposition gives rise to the probabilistic nature of quantum mechanics and is therefore one of the concepts at the heart of quantum mechanics. Although we have found that many students can successfully use the idea of superposition to calculate the probabilities of different measurement outcomes, they are often unable to identify the…

  15. Experimental generation and application of the superposition of higher-order Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-07-01

    Full Text Available This presentation provides information on experimental generation and application of the superposition of higher-order Bessel beams. The superposition of zero order Bessel beams can be used to measure the radius of curvature of a reflecting surface...

  16. Generation of discrete superpositions of coherent states in the anharmonic oscillator model

    CERN Document Server

    Miranowicz, A; Kielich, S; 10.1088/0954-8998/2/3/006

    2011-01-01

    The problem of generating discrete superpositions of coherent states in the process of light propagation through a nonlinear Kerr medium, which is modelled by the anharmonic oscillator, is discussed. It is shown that under an appropriate choice of the length (time) of the medium the superpositions with both even and odd numbers of coherent states can appear. Analytical formulae for such superpositions with a few components are given explicitly. General rules governing the process of generating discrete superpositions of coherent states are also given. The maximum number of well distinguished states that can be obtained for a given number of initial photons is estimated. The quasiprobability distribution $Q(\\alpha,\\alpha^*,t)$ representing the superposition states is illustrated graphically, showing regular structures when the component states are well separated.

  17. Homogeneous partial differential equations for superpositions of indeterminate functions of several variables

    Energy Technology Data Exchange (ETDEWEB)

    Asai, Kazuto [University of Aizu, Aizu-Wakamatsu (Japan)

    2009-02-28

    We determine essentially all partial differential equations satisfied by superpositions of tree type and of a further special type. These equations represent necessary and sufficient conditions for an analytic function to be locally expressible as an analytic superposition of the type indicated. The representability of a real analytic function by a superposition of this type is independent of whether that superposition involves real-analytic functions or C{sup {rho}}-functions, where the constant {rho} is determined by the structure of the superposition. We also prove that the function u defined by u{sup n}=xu{sup a}+yu{sup b}+zu{sup c}+1 is generally non-representable in any real (resp. complex) domain as f(g(x,y),h(y,z)) with twice differentiable f and differentiable g, h (resp. analytic f, g, h)

  18. Fugacity superposition: a new approach to dynamic multimedia fate modeling.

    Science.gov (United States)

    Hertwich, E G

    2001-08-01

    The fugacities, concentrations, or inventories of pollutants in environmental compartments as determined by multimedia environmental fate models of the Mackay type can be superimposed on each other. This is true for both steady-state (level III) and dynamic (level IV) models. Any problem in multimedia fate models with linear, time-invariant transfer and transformation coefficients can be solved through a superposition of a set of n independent solutions to a set of coupled, homogeneous first-order differential equations, where n is the number of compartments in the model. For initial condition problems in dynamic models, the initial inventories can be separated, e.g. by a compartment. The solution is obtained by adding the single-compartment solutions. For time-varying emissions, a convolution integral is used to superimpose solutions. The advantage of this approach is that the differential equations have to be solved only once. No numeric integration is required. Alternatively, the dynamic model can be simplified to algebraic equations using the Laplace transform. For time-varying emissions, the Laplace transform of the model equations is simply multiplied with the Laplace transform of the emission profile. It is also shown that the time-integrated inventories of the initial conditions problems are the same as the inventories in the steady-state problem. This implies that important properties of pollutants such as potential dose, persistence, and characteristic travel distance can be derived from the steady state.

  19. Linear superposition of sensory-evoked and ongoing cortical hemodynamics

    Directory of Open Access Journals (Sweden)

    Mohamad Saka

    2010-08-01

    Full Text Available Modern non-invasive brain imaging techniques utilise changes in cerebral blood flow, volume and oxygenation that accompany brain activation. However, stimulus-evoked hemodynamic responses display considerable inter-trial variability even when identical stimuli are presented and the sources of this variability are poorly understood. One of the sources of this response variation could be ongoing spontaneous hemodynamic fluctuations. To investigate this issue, 2-dimensional optical imaging spectroscopy was used to measure cortical hemodynamics in response to sensory stimuli in anaesthetised rodents Pre-stimulus cortical hemodynamics displayed spontaneous periodic fluctuations and as such, data from individual stimulus presentation trials were assigned to one of four groups depending on the phase angle of pre-stimulus hemodynamic fluctuations and averaged. This analysis revealed that sensory evoked cortical hemodynamics displayed distinctive response characteristics and magnitudes depending on the phase angle of ongoing fluctuations at stimulus onset. To investigate the origin of this phenomenon, ‘null-trails’ were collected without stimulus presentation. Subtraction of phase averaged ‘null trials’ from their phase averaged stimulus-evoked counterparts resulted in four similar time series that resembled the mean stimulus-evoked response. These analyses suggest that linear superposition of evoked and ongoing cortical hemodynamic changes may be a property of the structure of inter-trial variability.

  20. Compound measure of hand-foot-eye preference masked opposite turning behavior in healthy right-handers and non-right-handers: technical comment on Mohr et al. (2003).

    Science.gov (United States)

    Mohr, C; Bracha, H S

    2004-10-01

    A previous article reported opposite turning behavior in right-handers and non-right-handers (C. Mohr. T. Landis, H. S. Bracha, & P. Brugger, 2003). This observation appears contradictory to the 1st study on long-term spontaneous turning behavior in healthy participants (H. S. Bracha, D. J. Seitz, J. Otemaa, & S. D. Click, 1987). These latter authors found a complex interaction between hemispheric dominance, preferred turning side, and sex. C. Mohr et al. (2003) argued that the differentiation of the population in hemisphere-dominant groups by a compound measure of hand-foot-eye preference might have masked their recent finding. Thus, this commentary presents a reanalysis of the original data set (H. S. Bracha et al., 1987). Replicating recent observation, right-handers preferred left-sided turns; and non-righthanders, right-sided turns. This replication strengthens the proposition that handedness and turning behavior might depend on interhemispheric dopamine asymmetries. Copyright 2004 APA.

  1. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: Brenda Pagan- ...

  2. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? ...

  3. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd ... your vision. Privacy Policy Related New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

  4. Diabetic Eye Disease

    Science.gov (United States)

    ... Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetic Eye Disease What is diabetic eye disease? Diabetic eye disease is a group of ... loss can occur. How does diabetes affect my eyes? Diabetes affects your eyes when your blood glucose, ...

  5. A convolution-superposition dose calculation engine for GPUs

    Energy Technology Data Exchange (ETDEWEB)

    Hissoiny, Sami; Ozell, Benoit; Despres, Philippe [Departement de genie informatique et genie logiciel, Ecole polytechnique de Montreal, 2500 Chemin de Polytechnique, Montreal, Quebec H3T 1J4 (Canada); Departement de radio-oncologie, CRCHUM-Centre hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Montreal, Quebec H2L 4M1 (Canada)

    2010-03-15

    Purpose: Graphic processing units (GPUs) are increasingly used for scientific applications, where their parallel architecture and unprecedented computing power density can be exploited to accelerate calculations. In this paper, a new GPU implementation of a convolution/superposition (CS) algorithm is presented. Methods: This new GPU implementation has been designed from the ground-up to use the graphics card's strengths and to avoid its weaknesses. The CS GPU algorithm takes into account beam hardening, off-axis softening, kernel tilting, and relies heavily on raytracing through patient imaging data. Implementation details are reported as well as a multi-GPU solution. Results: An overall single-GPU acceleration factor of 908x was achieved when compared to a nonoptimized version of the CS algorithm implemented in PlanUNC in single threaded central processing unit (CPU) mode, resulting in approximatively 2.8 s per beam for a 3D dose computation on a 0.4 cm grid. A comparison to an established commercial system leads to an acceleration factor of approximately 29x or 0.58 versus 16.6 s per beam in single threaded mode. An acceleration factor of 46x has been obtained for the total energy released per mass (TERMA) calculation and a 943x acceleration factor for the CS calculation compared to PlanUNC. Dose distributions also have been obtained for a simple water-lung phantom to verify that the implementation gives accurate results. Conclusions: These results suggest that GPUs are an attractive solution for radiation therapy applications and that careful design, taking the GPU architecture into account, is critical in obtaining significant acceleration factors. These results potentially can have a significant impact on complex dose delivery techniques requiring intensive dose calculations such as intensity-modulated radiation therapy (IMRT) and arc therapy. They also are relevant for adaptive radiation therapy where dose results must be obtained rapidly.

  6. Collapsing a perfect superposition to a chosen quantum state without measurement.

    Science.gov (United States)

    Younes, Ahmed; Abdel-Aty, Mahmoud

    2014-01-01

    Given a perfect superposition of [Formula: see text] states on a quantum system of [Formula: see text] qubits. We propose a fast quantum algorithm for collapsing the perfect superposition to a chosen quantum state [Formula: see text] without applying any measurements. The basic idea is to use a phase destruction mechanism. Two operators are used, the first operator applies a phase shift and a temporary entanglement to mark [Formula: see text] in the superposition, and the second operator applies selective phase shifts on the states in the superposition according to their Hamming distance with [Formula: see text]. The generated state can be used as an excellent input state for testing quantum memories and linear optics quantum computers. We make no assumptions about the used operators and applied quantum gates, but our result implies that for this purpose the number of qubits in the quantum register offers no advantage, in principle, over the obvious measurement-based feedback protocol.

  7. Collapsing a perfect superposition to a chosen quantum state without measurement.

    Directory of Open Access Journals (Sweden)

    Ahmed Younes

    Full Text Available Given a perfect superposition of [Formula: see text] states on a quantum system of [Formula: see text] qubits. We propose a fast quantum algorithm for collapsing the perfect superposition to a chosen quantum state [Formula: see text] without applying any measurements. The basic idea is to use a phase destruction mechanism. Two operators are used, the first operator applies a phase shift and a temporary entanglement to mark [Formula: see text] in the superposition, and the second operator applies selective phase shifts on the states in the superposition according to their Hamming distance with [Formula: see text]. The generated state can be used as an excellent input state for testing quantum memories and linear optics quantum computers. We make no assumptions about the used operators and applied quantum gates, but our result implies that for this purpose the number of qubits in the quantum register offers no advantage, in principle, over the obvious measurement-based feedback protocol.

  8. Superpositions of higher-order bessel beams and nondiffracting speckle fields - (SAIP 2009)

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-07-01

    Full Text Available This poster presents a mechanism for the generation of the superposition of higher-order Bessel beams, which implements a ring slit aperture and spatial light modulator (SLM). The experimental technique is also adapted to generate nondiffracting...

  9. Your Eyes

    Science.gov (United States)

    ... people you know — like your grandparents — probably wear glasses. To the Brain! Think of the optic nerve as the great messenger in the back of your eye. The rods and cones of the retina change the colors and shapes you see into millions of nerve ...

  10. Evaluation of Class II treatment by cephalometric regional superpositions versus conventional measurements.

    Science.gov (United States)

    Efstratiadis, Stella; Baumrind, Sheldon; Shofer, Frances; Jacobsson-Hunt, Ulla; Laster, Larry; Ghafari, Joseph

    2005-11-01

    The aims of this study were (1) to evaluate cephalometric changes in subjects with Class II Division 1 malocclusion who were treated with headgear (HG) or Fränkel function regulator (FR) and (2) to compare findings from regional superpositions of cephalometric structures with those from conventional cephalometric measurements. Cephalographs were taken at baseline, after 1 year, and after 2 years of 65 children enrolled in a prospective randomized clinical trial. The spatial location of the landmarks derived from regional superpositions was evaluated in a coordinate system oriented on natural head position. The superpositions included the best anatomic fit of the anterior cranial base, maxillary base, and mandibular structures. Both the HG and the FR were effective in correcting the distoclusion, and they generated enhanced differential growth between the jaws. Differences between cranial and maxillary superpositions regarding mandibular displacement (Point B, pogonion, gnathion, menton) were noted: the HG had a more horizontal vector on maxillary superposition that was also greater (.0001 < P < .05) than the horizontal displacement observed with the FR. This discrepancy appeared to be related to (1) the clockwise (backward) rotation of the palatal and mandibular planes observed with the HG; the palatal plane's rotation, which was transferred through the occlusion to the mandibular plane, was factored out on maxillary superposition; and (2) the interaction between the inclination of the maxillary incisors and the forward movement of the mandible during growth. Findings from superpositions agreed with conventional angular and linear measurements regarding the basic conclusions for the primary effects of HG and FR. However, the results suggest that inferences of mandibular displacement are more reliable from maxillary than cranial superposition when evaluating occlusal changes during treatment.

  11. Harmonic Enhancement Mechanism of a Superposition State Atom Irradiated by Short Pulses

    Institute of Scientific and Technical Information of China (English)

    YANG Yu-Jun; ZHU Qi-Ren; CHEN Ji-Gen; HUANG Yu-Xin; GUO Fu-Ming; ZHANG Hong-Xing; SUN Jia-Zhong; ZHU Hong-Yu; WANG Li; WANG Hui

    2007-01-01

    We investigate the high-order harmonic generation (HHG) of a model atom whose initial state is prepared in a superposition of its ground state and an excited state irradiated by different duration laser pulses. Compared to the HHG generated from an atom whose initial state is in its ground state, its conversion efficiency obtains some enhancement. The enhancement originates from the higher ionization rate (rather than the ionization yield) of the atom with superposition initial state.

  12. Experimental Demonstration of Capacity-Achieving Phase-Shifted Superposition Modulation

    DEFF Research Database (Denmark)

    Estaran Tolosa, Jose Manuel; Zibar, Darko; Caballero Jambrina, Antonio

    2013-01-01

    We report on the first experimental demonstration of phase-shifted superposition modulation (PSM) for optical links. Successful demodulation and decoding is obtained after 240 km transmission for 16-, 32- and 64-PSM.......We report on the first experimental demonstration of phase-shifted superposition modulation (PSM) for optical links. Successful demodulation and decoding is obtained after 240 km transmission for 16-, 32- and 64-PSM....

  13. Creation of macroscopic superpositions of flow states with Bose-Einstein condensates

    OpenAIRE

    Dunningham, Jacob; Hallwood, David

    2006-01-01

    We present a straightforward scheme for creating macroscopic superpositions of different superfluid flow states of Bose-Einstein condensates trapped in optical lattices. This scheme has the great advantage that all the techniques required are achievable with current experiments. Furthermore, the relative difficulty of creating cats scales favorably with the size of the cat. This means that this scheme may be well-suited to creating superpositions involving large numbers of particles. Such sta...

  14. Nonlinear quantum mechanics, the superposition principle, and the quantum measurement problem

    Indian Academy of Sciences (India)

    Kinjalk Lochan; T P Singh

    2011-01-01

    There are four reasons why our present knowledge and understanding of quantum mechanics can be regarded as incomplete. (1) The principle of linear superposition has not been experimentally tested for position eigenstates of objects having more than about a thousand atoms. (2) There is no universally agreed upon explanation for the process of quantum measurement. (3) There is no universally agreed upon explanation for the observed fact that macroscopic objects are not found in superposition of position eigenstates. (4) Most importantly, the concept of time is classical and hence external to quantum mechanics: there should exist an equivalent reformulation of the theory which does not refer to an external classical time. In this paper we argue that such a reformulation is the limiting case of a nonlinear quantum theory, with the nonlinearity becoming important at the Planck mass scale. Such a nonlinearity can provide insights into the aforesaid problems. We use a physically motivated model for a nonlinear Schr ¨odinger equation to show that nonlinearity can help in understanding quantum measurement. We also show that while the principle of linear superposition holds to a very high accuracy for atomic systems, the lifetime of a quantum superposition becomes progressively smaller, as one goes from microscopic to macroscopic objects. This can explain the observed absence of position superpositions in macroscopic objects (lifetime is too small). It also suggests that ongoing laboratory experiments may be able to detect the finite superposition lifetime for mesoscopic objects in the near future.

  15. Determination of benzalkonium chloride in compound tropicamide eye drops by HPLC%HPLC法测定复方托吡卡胺滴眼液中苯扎氯铵的含量

    Institute of Scientific and Technical Information of China (English)

    何丹; 杨林

    2013-01-01

    Objective :To establish an HPLC method for detecting the content of Benzalkonium Chloride in Compound Tropicamide Eye Drops .Methods :A Alltech Alltima -CN column (250cm × 4 .6mm ,5μm) was used ,and the mobile phase was 0 .1mol・L -1 NaAc solution -acetonitrile (60 :40) ,HAc was used to adjust pH to 5 ,column temperature was 30℃ ,at a flow rate of 2 .0ml・min -1 and detection wavelength of 254 nm .Results :The linear range of Benzalkonium Chloride was 0 .02~0 .5mg・mL -1 ;The correlation coefficient was 0 .9999 .The average recovery of Benzalkonium Chloride was 98 .91% (RSD=0 .44% ,n=9 ) .Conclusion :The method is accurate ,simple ,rapid and suitable for the quality control of Benzalkonium Chloride in Compound Tropicamide eye drops .%目的:建立超高效液相色谱法测定复方托吡卡胺滴眼液中苯扎氯铵的含量测定方法。方法:色谱柱为Alltech Alltima -CN(250cm ×4.6mm ,5μm),流动相为0.1mol・L -1醋酸钠溶液(用冰醋酸调节pH值至5.0)-乙腈(60:40),检测波长254nm ,流速为2.0ml・min -1,柱温30℃,进样体积50μL。结果:苯扎氯铵在0.02至0.5mg・mL -1浓度范围内线性关系良好(r=0.9999);平均回收率为98.91%,RSD=0.44%(n=9)。结论:该方法准确、简便、快速、可靠,能有效控制复方托吡卡胺滴眼液中苯扎氯铵的含量。

  16. Why Do Eyes Water?

    Science.gov (United States)

    ... Lifesaver Kids Talk About: Coaches Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? Print ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  17. Eye muscle repair - discharge

    Science.gov (United States)

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  18. Why Do Eyes Water?

    Science.gov (United States)

    ... Happens in the Operating Room? Why Do Eyes Water? KidsHealth > For Kids > Why Do Eyes Water? A ... out of your nose. continue Why Do Eyes Water? Eyes water for lots of different reasons besides ...

  19. About the Eye

    Medline Plus

    Full Text Available ... eye behind the iris that helps to focus light on the retina. It allows the eye to ... of the eye. It regulates the amount of light entering the eye through the pupil. Pupil (PYOO- ...

  20. Recommended Sports Eye Protectors

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  1. Eye Safety at Home

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  2. Eye Safety at Work

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  3. Eye Movement Disorders

    Science.gov (United States)

    ... work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder in ... the eyes, sometimes called "dancing eyes" Some eye movement disorders are present at birth. Others develop over time ...

  4. About the Eye

    Medline Plus

    Full Text Available ... eye behind the iris that helps to focus light on the retina. It allows the eye to ... of the eye. It regulates the amount of light entering the eye through the pupil. Pupil (PYOO- ...

  5. Conjunctivitis (Pink Eye)

    Science.gov (United States)

    ... that can be embedded on web pages. Conjunctivitis (Pink Eye) One-Page Overview Pink, itchy eyes? Conjunctivitis – ... protect yourself from getting and spreading pink eye . Pink Eye: What To Do Discusses causes and treatment, ...

  6. Eye Disease Simulations

    Science.gov (United States)

    ... USAJobs Home > Eye Health Information > Eye Disease Simulations Eye Disease Simulations Age-Related Macular Degeneration Cataract Diabetic ... information page Back to top Diabetic Retinopathy Diabetic Eye Disease information page Back to top Glaucoma Glaucoma ...

  7. Eye Involvement in TSC

    Science.gov (United States)

    ... Privacy Policy Sitemap Learn Engage Donate About TSC Eyes Campbell (1905) first described the eye involvement in ... some form of eye involvement. Nonretinal and Retinal Eye Findings Facial angiofibromas may involve the eyelids of ...

  8. Eye Complications in IBD

    Science.gov (United States)

    ... Home > Resources > Eye Complications in IBD Go Back Eye Complications in IBD Email Print + Share Approximately 10% ... doctor’s attention sooner rather than later. TYPES OF EYE DISORDERS UVEITIS One of the most common eye ...

  9. Eye Contricks

    Directory of Open Access Journals (Sweden)

    Nicholas J Wade

    2011-06-01

    Full Text Available Pictorial images are icons as well as eye-cons: they provide distillations of objects or ideas into simpler shapes. They create the impression of representing that which cannot be presented. Even at the level of the photograph, the links between icon and object are tenuous. The dimensions of depth and motion are missing from icons, and these alone introduce all manner of potential ambiguities. The history of art can be considered as exploring the missing link between icon and object. Eye-cons can also be illusions—tricks of vision so that what is seen does not necessarily correspond to what is physically presented. Pictorial images can be spatialised or stylised; spatialised images generally share some of the projective characteristics of the object represented. Written words are also icons, but they do not resemble the objects they represent—they are stylised or conventional. Icons as stylised words and spatialised images were set in delightful opposition by René Magritte in a series of pipe paintings, and this theme is here alluded to. Most of visual science is now concerned with icons—two-dimensional displays on computer monitors. Is vision now the science of eye-cons?

  10. Attosecond probing of state-resolved ionization and superpositions of atoms and molecules

    Science.gov (United States)

    Leone, Stephen

    2016-05-01

    Isolated attosecond pulses in the extreme ultraviolet are used to probe strong field ionization and to initiate electronic and vibrational superpositions in atoms and small molecules. Few-cycle 800 nm pulses produce strong-field ionization of Xe atoms, and the attosecond probe is used to measure the risetimes of the two spin orbit states of the ion on the 4d inner shell transitions to the 5p vacancies in the valence shell. Step-like features in the risetimes due to the subcycles of the 800 nm pulse are observed and compared with theory to elucidate the instantaneous and effective hole dynamics. Isolated attosecond pulses create massive superpositions of electronic states in Ar and nitrogen as well as vibrational superpositions among electronic states in nitrogen. An 800 nm pulse manipulates the superpositions, and specific subcycle interferences, level shifting, and quantum beats are imprinted onto the attosecond pulse as a function of time delay. Detailed outcomes are compared to theory for measurements of time-dynamic superpositions by attosecond transient absorption. Supported by DOE, NSF, ARO, AFOSR, and DARPA.

  11. Selective preparation of the maximum coherent superposition state in four-level atoms

    Institute of Scientific and Technical Information of China (English)

    Li Deng; Yueping Niu; Shangqing Gong

    2011-01-01

    We demonstrate that the maximum coherent superposition state can be selectively prepared using a sequence of pulse pairs in lambda-type atomic systems, with the final level as a doublet. In each pair, the Stocks pulse comes before the pump pulse, with their back edges overlapping. Numerical results indicate that by tuning the interval of the adjacent pulse pairs, the selective maximum coherent superposition state preparation between the initial and one of the final levels can be achieved. The phenomenon is caused by the accumulative property of the pulse sequence.%The coherent superposition state in atoms or molecules plays a crucial role in quantum physics.It has applications in many areas such as electromagnetically induced transparency[1-5],quantum information[6-8] and control of chemical reaction[9-11].Many schemes can prepare the coherent superposition state.For instance,the fractional stimulated Raman adiabatic passage(F-STIRAP) [12] and the coherent population trapping[13] can obtain the maximum coherent superposition state of the two lower levels in lambda-type atoms.Our group also proposed several schemes to achieve this goal,such as the methods based on the STIRAP[14,15] and the pulse train method[16].

  12. Eye Contricks

    Directory of Open Access Journals (Sweden)

    N Wade

    2011-04-01

    Full Text Available Icons are eye-cons: they provide a distillation of a complex object or idea into a simple pictorial shape. They create the impression of representing that which cannot be presented. Even at the level of the photograph, the links between icon and object are tenuous. The dimension of distance or depth is missing from the icon, and this alone introduces all manner of potential ambiguities. The history of art can be considered as an exploration of the missing link between icon and object. Eye-cons are more honest—they are tricks of vision so that what is seen does not necessarily correspond to what is presented. They are visual allusions rather than visual illusions, although they can display illusory effects. At its broadest, icon can be equated with image. The concept of image has thrived on its vagueness, and so attempts have been made to refine it. An icon corresponds to an optical image: it shares some of the projective characteristics of the object represented. Written words are also icons but they do not resemble the objects they represent—they are stylised or conventional rather than spatialised and projective. Words and images were set in delightful opposition by René Magritte (1898-1967 in a series of pipe paintings, and he also played on the theme of the arbitrariness of the verbal labels assigned to objects. What is surprising is that Magritte did not apply his painterly skills to transforming the word shapes he used. A similar reluctance to transform the typefaces pervades visual poetry. My interests are in the visual rather than the poetic dimension, and I will present a range of my own eye contricks which play with letter and word shapes in a variety of ways.

  13. An Approximate Analytical (Structural Superposition in Terms of Two, or More, α- Circuits of the Same Topology: Pt.1 – Description of the Superposition

    Directory of Open Access Journals (Sweden)

    E. Gluskin

    2013-09-01

    Full Text Available One-ports named “f-circuits”, composed of similar conductors described by a monotonic polynomial, or quasi-polynomial (i.e. with positive but not necessarily integer, powers characteristic i = f(v are studied, focusing on the algebraic map f → F. Here F(. is the input conductivity characteristic; i.e., iin = F(vin is the input current. The “power-law” “a-circuit” introduced in [1], for which f(v ~ v a , is an important particular case. By means of a generalization of a parallel connection, the f-circuits are constructed from the a-circuits of the same topology, with different a, so that the given topology is kept, and ‘f’ is an additive function of the connection. We observe and consider an associated, generally approximated, but, in all of the cases studied, always high-precision, specific superposition. This superposition is in terms of f → F, and it means that F(. of the connection is close to the sum of the input currents of the independent a-circuits, all connected in parallel to the same source. In other words, F(. is well approximated by a linear combination of the same degrees of the independent variable as in f(., i.e. the map of the characteristics f → F is close to a linear one. This unexpected result is useful for understanding nonlinear algebraic circuits, and is missed in the classical theory. The cases of f(v = D1v + D2v 2 and f(v = D1v + D3v 3, are analyzed in examples. Special topologies when the superposition must be ideal, are also considered. In the second part [2] of the work the “circuit mechanism” that is responsible for the high precision of the superposition, in the most general case, is explained.

  14. New concept in nutrition for the maintenance of the aging eye redox regulation and therapeutic treatment of cataract disease; synergism of natural antioxidant imidazole-containing amino acid-based compounds, chaperone, and glutathione boosting agents: a systemic perspective on aging and longevity emerged from studies in humans.

    Science.gov (United States)

    Babizhayev, Mark A

    2010-01-01

    Cataract, opacification of the lens, is one of the commonest causes of loss of useful vision during aging, with an estimated 16 million people world-wide affected. The role of nutritional supplementation in prevention of onset or progression of ocular disease is of interest to health care professionals and patients. The aging eye seems to be at considerable risk from oxidative stress. This review outlines the potential role of the new nutritional strategy on redox balance in age-related eye diseases and detail how the synergism and interaction of imidazole-containing amino acid-based compounds (nonhydrolized L-carnosine, histidine), chaperone agents (such as, L-carnosine, D-pantethine), glutathione-boosting agents (N-acetylcysteine, vitamin E, methionine), and N-acetylcarnosine eye drops plays key roles in the function and maintenance of the redox systems in the aging eye and in the treatment of human cataract disease. A novel patented oral health supplement is presented which enhances the anticataract activity of eye drops and activates functional visual acuity. The clinical data demonstrate the effectiveness and safety of a combined oral health care treatment with amino acids possessing chaperone-like activity with N-acetylcarnosine lubricant eye drops. L-carnosine and N-acetylcarnosine protected the chaperone activity of alpha-crystallin and reduced the increased posttranslational modifications of lens proteins. Biological activities of the nonhydrolyzed carnosine in the oral formulation are based on its antioxidant and antiglycating (transglycating) action that, in addition to heavy metal chelation and pH-buffering ability, makes carnosine an essential factor for preventing sight-threatening eye disorders having oxidative stress in their pathogenesis, neurodegeneration, and accumulation of senile features. The findings suggest that synergism is required between carnosine or other imidazole-containing compounds and reduced glutathione in tissues and cells for

  15. [Superposition of the motor commands during creation of static efforts by human hand muscles].

    Science.gov (United States)

    Vereshchaka, I V; Horkovenko, A V

    2012-01-01

    The features of superposition of central motor commands (CMCs) have been studied during generation of the "two-joint" isometric efforts by hand. The electromyogram (EMG) amplitudes which were recorded from the humeral belt and shoulder muscles have been used for estimation of the CMCs intensity. The forces were generated in the horizontal plane of the work space; the position of arm was fixed. Two vectors of equal amplitudes and close direction and their geometrical sum were compared. The hypothesis of the CMCs' superposition in the task of the force vector summation has been examined. The directions of the constituent and resulting forces with satisfactory superposition of the CMCs were defined. Differences in the co-activation patterns for flexor and extensor muscles of both joints were shown. The high level of the flexor muscles activity has been observed during extension efforts, while the flexion directions demonstrated much weaker activation of the extensor muscles.

  16. Oblique superposition of two elliptically polarized lightwaves using geometric algebra: is energy-momentum conserved?

    Science.gov (United States)

    Sze, Michelle Wynne C; Sugon, Quirino M; McNamara, Daniel J

    2010-11-01

    In this paper, we use Clifford (geometric) algebra Cl(3,0) to verify if electromagnetic energy-momentum density is still conserved for oblique superposition of two elliptically polarized plane waves with the same frequency. We show that energy-momentum conservation is valid at any time only for the superposition of two counter-propagating elliptically polarized plane waves. We show that the time-average energy-momentum of the superposition of two circularly polarized waves with opposite handedness is conserved regardless of the propagation directions of the waves. And, we show that the resulting momentum density of the superposed waves generally has a vector component perpendicular to the momentum densities of the individual waves.

  17. Quantum tic-tac-toe: A teaching metaphor for superposition in quantum mechanics

    Science.gov (United States)

    Goff, Allan

    2006-11-01

    Quantum tic-tac-toe was developed as a metaphor for the counterintuitive nature of superposition exhibited by quantum systems. It offers a way of introducing quantum physics without advanced mathematics, provides a conceptual foundation for understanding the meaning of quantum mechanics, and is fun to play. A single superposition rule is added to the child's game of classical tic-tac-toe. Each move consists of a pair of marks subscripted by the number of the move ("spooky" marks) that must be placed in different squares. When a measurement occurs, one spooky mark becomes real and the other disappears. Quantum tic-tac-toe illustrates a number of quantum principles including states, superposition, collapse, nonlocality, entanglement, the correspondence principle, interference, and decoherence. The game can be played on paper or on a white board. A Web-based version provides a refereed playing board to facilitate the mechanics of play, making it ideal for classrooms with a computer projector.

  18. Reconstruction and prediction of coherent acoustic field with the combined wave superposition approach

    Institute of Scientific and Technical Information of China (English)

    LI Weibing; CHEN Jian; YU Fei; CHEN Xinzhao

    2006-01-01

    The routine wave superposition approach cannot be used in reconstruction and prediction of a coherent acoustic field, because it is impossible to separate the pressures generated by individual sources. According to the superposition theory of the coherent acoustic field , a novel method based on the combined wave superposition approach is developed to reconstruct and predict the coherent acoustic field by building the combined pressure matching matrixes between the hologram surfaces and the sources. The method can reconstruct the acoustic information on surfaces of the individual sources, and it is possible to predict the acoustic field radiated from every source and the total coherent acoustic field can also be calculated spontaneously. The experimental and numerical simulation results show that this method can effectively solve the holographic reconstruction and prediction of the coherent acoustic field and it can also be used as a coherent acoustic field separation technique. The study on this novel method extends the application scope of the acoustic holography technique.

  19. Quantum Superpositions and the Representation of Physical Reality Beyond Measurement Outcomes and Mathematical Structures

    CERN Document Server

    de Ronde, Christian

    2016-01-01

    In this paper we intend to discuss the importance of providing a physical representation of quantum superpositions which goes beyond the mere reference to mathematical structures and measurement outcomes. This proposal goes in the opposite direction of the orthodox project which attempts to "bridge the gap" between the quantum formalism and common sense "classical reality" --precluding, right from the start, the possibility of interpreting quantum superpositions through non-classical notions. We will argue that in order to restate the problem of interpretation of quantum mechanics in truly ontological terms we require a radical revision of the problems and definitions addressed within the orthodox literature. On the one hand, we will discuss the need of providing a formal redefinition of superpositions which captures their contextual character. On the other hand, we attempt to replace the focus on the measurement problem, which concentrates on the justification of measurement outcomes from "weird" superposed ...

  20. Quantum superposition, entanglement, and state teleportation of a microorganism on an electromechanical oscillator

    CERN Document Server

    Li, Tongcang

    2016-01-01

    Schr\\"odinger's thought experiment to prepare a cat in a superposition of both alive and dead states reveals profound consequences of quantum mechanics and has attracted enormous interests. Here we propose a straightforward method to create quantum superposition states of a living microorganism by putting a small bacterium on top of an electromechanical oscillator. Our proposal is based on recent developments that the center-of-mass oscillation of a 15-$\\mu$m-diameter aluminium membrane has been cooled to its quantum ground state [Nature 475, 359 (2011)], and entangled with a microwave field [Science, 342, 710 (2013)]. A microorganism with a mass much smaller than the mass of the electromechanical membrane will not significantly affect the quality factor of the membrane and can be cooled to the quantum ground state together with the membrane. Quantum superposition and teleportation of its center-of-mass motion state can be realized with the help of superconducting microwave circuits. More importantly, the int...

  1. Macroscopic quantum superposition of spin ensembles with ultra-long coherence times via superradiant masing

    CERN Document Server

    Jin, Liang; Wrachtrup, Jörg; Liu, Ren-Bao

    2014-01-01

    Macroscopic quantum phenomena such as lasers, Bose-Einstein condensates, superfluids, and superconductors are of great importance in foundations and applications of quantum mechanics. In particular, quantum superposition of a large number of spins in solids is highly desirable for both quantum information processing and ultrasensitive magnetometry. Spin ensembles in solids, however, have rather short collective coherence time (typically less than microseconds). Here we demonstrate that under realistic conditions it is possible to maintain macroscopic quantum superposition of a large spin ensemble (such as about ~10^{14} nitrogen-vacancy center electron spins in diamond) with an extremely long coherence time ~10^8 sec under readily accessible conditions. The scheme, following the mechanism of superradiant lasers, is based on superradiant masing due to coherent coupling between collective spin excitations (magnons) and microwave cavity photons. The coherence time of the macroscopic quantum superposition is the ...

  2. Dense coding scheme using superpositions of Bell-states and its NMR implementation

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Jingfu; XIE; Jingyi; DENG; Zhiwei; LU; Zhiheng

    2005-01-01

    Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR)quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system.

  3. Quantum decoherence time scales for ionic superposition states in ion channels

    Science.gov (United States)

    Salari, V.; Moradi, N.; Sajadi, M.; Fazileh, F.; Shahbazi, F.

    2015-03-01

    There are many controversial and challenging discussions about quantum effects in microscopic structures in neurons of the brain and their role in cognitive processing. In this paper, we focus on a small, nanoscale part of ion channels which is called the "selectivity filter" and plays a key role in the operation of an ion channel. Our results for superposition states of potassium ions indicate that decoherence times are of the order of picoseconds. This decoherence time is not long enough for cognitive processing in the brain, however, it may be adequate for quantum superposition states of ions in the filter to leave their quantum traces on the selectivity filter and action potentials.

  4. Generation of squeezed-state superpositions via time-dependent Kerr nonlinearities

    CERN Document Server

    León-Montiel, R de J

    2015-01-01

    We put forward an experimental scheme for direct generation of optical squeezed coherent-state superpositions. The proposed setup makes use of an optical cavity, filled with a nonlinear Kerr medium, whose frequency is allowed to change during time evolution. By exactly solving the corresponding time-dependent anharmonic-oscillator Hamiltonian, we demonstrate that squeezed-state superpositions can be generated in an optical cavity. Furthermore, we show that the squeezing degree of the produced states can be tuned by properly controlling the frequency shift of the cavity, a feature that could be useful in many quantum information protocols, such as quantum teleportation and quantum computing.

  5. The general use of the time-temperature-pressure superposition principle

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Koblitz

    This note is a supplement to Dynamic of Polymeric Liquids (DPL) section 3.6(a). DPL do only concern material functions and only the effect of the temperature on these. This is a short introduction to the general use of the time-temperature-pressure superposition principle.......This note is a supplement to Dynamic of Polymeric Liquids (DPL) section 3.6(a). DPL do only concern material functions and only the effect of the temperature on these. This is a short introduction to the general use of the time-temperature-pressure superposition principle....

  6. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye ... Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? Written By: Kierstan ...

  7. About the Eye

    Medline Plus

    Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables About the Eye Your eyes ...

  8. About the Eye

    Medline Plus

    Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables About the Eye Your eyes ...

  9. Determination of Benzalkonium Chloride in Compound Aspartate, Vitamin B6 and Dipotassium Glycyrrhe-tate Eye Drops%复方门冬维甘滴眼液中苯扎氯铵的测定

    Institute of Scientific and Technical Information of China (English)

    董超琪

    2014-01-01

    目的::建立测定复方门冬维甘滴眼液中苯扎氯铵含量的方法。方法:采用Agilent Zorbax C18色谱柱(150 mm ×4.6 mm,5μm),以乙腈-5 mmol·L-1醋酸铵溶液(含1%三乙胺,用冰醋酸调节pH至5.0±0.5)(65∶35)为流动相,流速为1.0 ml·min-1,检测波长为214 nm。结果:苯扎氯铵在50.00~150.00μg·ml-1范围内与峰面积线性关系良好,r=0.9980;平均回收率为99.1%,RSD为0.6%。结论:该方法简便,迅速,灵敏度高,具有良好的重复性及回收率,可用于复方门冬维甘滴眼液中苯扎氯铵的测定。%Objective:To develop a method to determine benzalkonium chloride in compound aspartate, vitamin B6 and dipotassi-umglycyrrhetateeyedrops.Methods:TheseparationwasperformedonanAgilentZorbaxC18(150mm×4.6mm,5μm)column. The mobile phase consisted of acetonitrile-5 mmol·L-1 ammonium acetate ( in which 1% triethylamine was added, then the pH value was adjusted to 5. 0 ± 0. 5 by acetic acid) 65∶35(v/v). The flow rate was 1. 0 ml·min-1 and the detection wavelength was 214nm. Re-sults:Benzalkonium chloride had a good linearity within the range of 50. 00-150. 00μg·ml-1(r=0. 998 0), and the average recovery was 99. 1%(RSD=0. 6%). Conclusion:The method is simple, rapid and sensitive with good repeatability and recovery. It can be used to determine benzalkoinum chloride in compound aspartate, vitamin B6 and dipotassium glycyrrhetate eye drops.

  10. EyeGENE

    Data.gov (United States)

    U.S. Department of Health & Human Services — The eyeGENE® Biorepository and corresponding Database contain family history and clinical eye exam data from subjects enrolled in eyeGENE® Program coupled to...

  11. Eye Injuries in Sports

    Science.gov (United States)

    ... in Sports Which sports cause the most eye injuries?Sports cause more than 40,000 eye injuries each ... and racquet sports.When it comes to eye injuries, sports can be classified as low risk, high risk ...

  12. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Member Services Advocacy Foundation About Subspecialties & More Eye Health Home Annual Meeting Clinical Education Practice Management Member ... Center Redmond Ethics Center Global Ophthalmology Guide Eye Health Find an Ophthalmologist Academy Store Eye Health A- ...

  13. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Member Services Advocacy Foundation About Subspecialties & More Eye Health Home Annual Meeting Clinical Education Practice Management Member ... Center Redmond Ethics Center Global Ophthalmology Guide Eye Health Find an Ophthalmologist Academy Store Eye Health A- ...

  14. Eye muscle repair - slideshow

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/presentations/100062.htm Eye muscle repair - series—Normal anatomy To use the sharing ... the eyeball to the eye socket. The external muscles of the eye are found behind the conjunctiva. ...

  15. Pink Eye (Conjunctivitis)

    Science.gov (United States)

    ... you have allergic conjunctivitis. Preventing the spread of pink eye Practice good hygiene to control the spread ... can return to school or child care. Preventing pink eye in newborns Newborns' eyes are susceptible to ...

  16. About the Eye

    Medline Plus

    Full Text Available ... Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision ... to More Information Optical Illusions Printables About the Eye Your eyes are made up of many different ...

  17. About the Eye

    Science.gov (United States)

    ... Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision ... to More Information Optical Illusions Printables About the Eye Your eyes are made up of many different ...

  18. Eye Injuries (For Parents)

    Science.gov (United States)

    ... Habits for TV, Video Games, and the Internet Eye Injuries KidsHealth > For Parents > Eye Injuries Print A ... sand, dirt, and other foreign bodies on the eye surface) Wash your hands thoroughly before touching the ...

  19. Arthropod eyes: The early Cambrian fossil record and divergent evolution of visual systems.

    Science.gov (United States)

    Strausfeld, Nicholas J; Ma, Xiaoya; Edgecombe, Gregory D; Fortey, Richard A; Land, Michael F; Liu, Yu; Cong, Peiyun; Hou, Xianguang

    2016-03-01

    Four types of eyes serve the visual neuropils of extant arthropods: compound retinas composed of adjacent facets; a visual surface populated by spaced eyelets; a smooth transparent cuticle providing inwardly directed lens cylinders; and single-lens eyes. The first type is a characteristic of pancrustaceans, the eyes of which comprise lenses arranged as hexagonal or rectilinear arrays, each lens crowning 8-9 photoreceptor neurons. Except for Scutigeromorpha, the second type typifies Myriapoda whose relatively large eyelets surmount numerous photoreceptive rhabdoms stacked together as tiers. Scutigeromorph eyes are facetted, each lens crowning some dozen photoreceptor neurons of a modified apposition-type eye. Extant chelicerate eyes are single-lensed except in xiphosurans, whose lateral eyes comprise a cuticle with a smooth outer surface and an inner one providing regular arrays of lens cylinders. This account discusses whether these disparate eye types speak for or against divergence from one ancestral eye type. Previous considerations of eye evolution, focusing on the eyes of trilobites and on facet proliferation in xiphosurans and myriapods, have proposed that the mode of development of eyes in those taxa is distinct from that of pancrustaceans and is the plesiomorphic condition from which facetted eyes have evolved. But the recent discovery of enormous regularly facetted compound eyes belonging to early Cambrian radiodontans suggests that high-resolution facetted eyes with superior optics may be the ground pattern organization for arthropods, predating the evolution of arthrodization and jointed post-protocerebral appendages. Here we provide evidence that compound eye organization in stem-group euarthropods of the Cambrian can be understood in terms of eye morphologies diverging from this ancestral radiodontan-type ground pattern. We show that in certain Cambrian groups apposition eyes relate to fixed or mobile eyestalks, whereas other groups reveal concomitant

  20. Adiabatic generation of arbitrary coherent superpositions of two quantum states: Exact and approximate solutions

    Science.gov (United States)

    Zlatanov, Kaloyan N.; Vitanov, Nikolay V.

    2017-07-01

    The common objective of the application of adiabatic techniques in the field of quantum control is to transfer a quantum system from one discrete energy state to another. These techniques feature both high efficiency and insensitivity to variations in the experimental parameters, e.g., variations in the driving field amplitude, duration, frequency, and shape, as well as fluctuations in the environment. Here we explore the potential of adiabatic techniques for creating arbitrary predefined coherent superpositions of two quantum states. We show that an equally weighted coherent superposition can be created by temporal variation of the ratio between the Rabi frequency Ω (t ) and the detuning Δ (t ) from 0 to ∞ (case 1) or vice versa (case 2), as it is readily deduced from the explicit adiabatic solution for the Bloch vector. We infer important differences between cases 1 and 2 in the composition of the created coherent superposition: The latter depends on the dynamical phase of the process in case 2, while it does not depend on this phase in case 1. Furthermore, an arbitrary coherent superposition of unequal weights can be created by using asymptotic ratios of Ω (t )/Δ (t ) different from 0 and ∞ . We supplement the general adiabatic solution with analytic solutions for three exactly soluble models: two trigonometric models and the hyperbolic Demkov-Kunike model. They allow us not only to demonstrate the general predictions in specific cases but also to derive the nonadiabatic corrections to the adiabatic solutions.

  1. Chaos and Complexities Theories. Superposition and Standardized Testing: Are We Coming or Going?

    Science.gov (United States)

    Erwin, Susan

    2005-01-01

    The purpose of this paper is to explore the possibility of using the principle of "superposition of states" (commonly illustrated by Schrodinger's Cat experiment) to understand the process of using standardized testing to measure a student's learning. Comparisons from literature, neuroscience, and Schema Theory will be used to expound upon the…

  2. Transforming squeezed light into large-amplitude coherent-state superposition

    DEFF Research Database (Denmark)

    Nielsen, Anne Ersbak Bang; Mølmer, Klaus

    2007-01-01

    A quantum superposition of two coherent states of light with small amplitude can be obtained by subtracting a photon from a squeezed vacuum state. In experiments this preparation can be made conditioned on the detection of a photon in the field from a squeezed light source. We propose and analyze...

  3. A note on “Generalized superposition of two squeezed states: generation and statistical properties”

    OpenAIRE

    Avelar, A. T.; Malbouisson, J.M.C.; Baseia, B.

    2004-01-01

    Texto completo: acesso restrito. p. 139-143 A previous scheme [Physica A 280 (2003) 346] showed how to create a generalized superposition of two squeezed states for stationary fields and studied its statistical properties. Here we show how to extend this result for travelling fields.

  4. Measuring the orbital angular momentum density for a superposition of Bessel beams

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2012-01-01

    Full Text Available To measure the Orbital Angular Momentum (OAM) density of superposition fields two steps are needed: generation and measurement. An azimuthally-varying phase (bounded by a ring-slit) placed in the spatial frequency domain produces a higher...

  5. Reservoir engineering of a mechanical resonator: generating a macroscopic superposition state and monitoring its decoherence

    Science.gov (United States)

    Asjad, Muhammad; Vitali, David

    2014-02-01

    A deterministic scheme for generating a macroscopic superposition state of a nanomechanical resonator is proposed. The nonclassical state is generated through a suitably engineered dissipative dynamics exploiting the optomechanical quadratic interaction with a bichromatically driven optical cavity mode. The resulting driven dissipative dynamics can be employed for monitoring and testing the decoherence processes affecting the nanomechanical resonator under controlled conditions.

  6. Proportional fair scheduling with superposition coding in a cellular cooperative relay system

    DEFF Research Database (Denmark)

    Kaneko, Megumi; Hayashi, Kazunori; Popovski, Petar

    2013-01-01

    Many works have tackled on the problem of throughput and fairness optimization in cellular cooperative relaying systems. Considering firstly a two-user relay broadcast channel, we design a scheme based on superposition coding (SC) which maximizes the achievable sum-rate under a proportional fairn...

  7. Generation of Superpositions of Two Bloch States in an Ion Trap

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2003-01-01

    We propose a scheme for the generation of superpositions of two Bloch states for a collection of ions. Inthe scheme the ions are trapped in a linear potential and interact with laser beams. Our scheme does not put anyrequirement on the Lamb-Dicke parameters.

  8. Using Musical Intervals to Demonstrate Superposition of Waves and Fourier Analysis

    Science.gov (United States)

    LoPresto, Michael C.

    2013-01-01

    What follows is a description of a demonstration of superposition of waves and Fourier analysis using a set of four tuning forks mounted on resonance boxes and oscilloscope software to create, capture and analyze the waveforms and Fourier spectra of musical intervals.

  9. Application of time-temperature-stress superposition on creep of wood-plastic composites

    Science.gov (United States)

    Chang, Feng-Cheng; Lam, Frank; Kadla, John F.

    2013-08-01

    Time-temperature-stress superposition principle (TTSSP) was widely applied in studies of viscoelastic properties of materials. It involves shifting curves at various conditions to construct master curves. To extend the application of this principle, a temperature-stress hybrid shift factor and a modified Williams-Landel-Ferry (WLF) equation that incorporated variables of stress and temperature for the shift factor fitting were studied. A wood-plastic composite (WPC) was selected as the test subject to conduct a series of short-term creep tests. The results indicate that the WPC were rheologically simple materials and merely a horizontal shift was needed for the time-temperature superposition, whereas vertical shifting would be needed for time-stress superposition. The shift factor was independent of the stress for horizontal shifts in time-temperature superposition. In addition, the temperature- and stress-shift factors used to construct master curves were well fitted with the WLF equation. Furthermore, the parameters of the modified WLF equation were also successfully calibrated. The application of this method and equation can be extended to curve shifting that involves the effects of both temperature and stress simultaneously.

  10. Macroscopic Quantum Superposition States in a Model of Photon-Supersonic Phonon Interaction

    Institute of Scientific and Technical Information of China (English)

    CHAI Jin-Hua; WANG Yan-Bang; LU Yi-Qun

    2000-01-01

    A model of photon-hypersonic phonon interaction is proposed. The evolution of macroscopic quantum superpo sition states is analyzed, including the wave function and number distribution. It is shown that a superposition state of hypersonic phonon modes can be generated in the case of nondetuning and no losses.

  11. Teleportation of a Superposition of Three Orthogonal States of an Atom via Photon Interference

    Institute of Scientific and Technical Information of China (English)

    ZHENG Shi-Biao

    2006-01-01

    We propose a scheme to teleport a superposition of three states of an atom trapped in a cavity to a second atom trapped in a remote cavity. The scheme is based on the detection of photons leaking from the cavities after the atom-cavity interaction.

  12. Visual fields and eye morphology support color vision in a color-changing crab-spider.

    Science.gov (United States)

    Insausti, Teresita C; Defrize, Jérémy; Lazzari, Claudio R; Casas, Jérôme

    2012-03-01

    Vision plays a major role in many spiders, being involved in prey hunting, orientation or substrate choice, among others. In Misumena vatia, which experiences morphological color changes, vision has been reported to be involved in substrate color matching. Electrophysiological evidence reveals that at least two types of photoreceptors are present in this species, but these data are not backed up by morphological evidence. This work analyzes the functional structure of the eyes of this spider and relates it to its color-changing abilities. A broad superposition of the visual field of the different eyes was observed, even between binocular regions of principal and secondary eyes. The frontal space is simultaneously analyzed by four eyes. This superposition supports the integration of the visual information provided by the different eye types. The mobile retina of the principal eyes of this spider is organized in three layers of three different types of rhabdoms. The third and deepest layer is composed by just one large rhabdom surrounded by dark screening pigments that limit the light entry. The three pairs of secondary eyes have all a single layer of rhabdoms. Our findings provide strong support for an involvement of the visual system in color matching in this spider.

  13. Laser photocoagulation - eye

    Science.gov (United States)

    Laser coagulation; Laser eye surgery; Photocoagulation; Laser photocoagulation - diabetic eye disease; Laser photocoagulation - diabetic retinopathy; Focal photocoagulation; Scatter (or pan retinal) photocoagulation; Proliferative ...

  14. WAVE SUPERPOSITION METHOD BASED ON VIRTUAL SOURCE BOUNDARY WITH COMPLEX RADIUS VECTOR FOR SOLVING ACOUSTIC RADIATION PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    XiangYu; HuangYuying; MaXiaoqiang

    2004-01-01

    By virtue of the comparability between the wave superposition method and the dynamic analysis of structures, a general format for overcoming the non-uniqueness of solution induced by the wave superposition method at the eigenfrequencies of the corresponding interior problems is proposed. By adding appropriate damp to the virtual source system of the wave superposition method, the unique solutions for all wave numbers can be ensured. Based on this thought, a novel method-wave superposition method with complex radius vector is constructed.Not only is the computational time of this method approximately equal to that of the standard wave superposition method, but also the accuracy is much higher compared with other correlative methods. Finally, by taking the pulsating sphere and oscillating sphere as examples, the results of calculation show that the present method can effectively overcome the non-uniqueness problem.

  15. Eating for Your Eyes

    Science.gov (United States)

    Stastny, Sherri Nordstrom; Garden-Robinson, Julie

    2011-01-01

    An educational program targeting older adults was developed to increase knowledge regarding nutrition and eye health. With age, the chance for eye disease increases, so prevention is critical. The Eating for Your Eyes program has promoted behavior changes regarding eye health among the participants. This program is easily replicated and use is…

  16. Eye Injuries (For Parents)

    Science.gov (United States)

    ... the eye nausea or vomiting after an eye injury Think Prevention! Kids who play sports should wear protective goggles or unbreakable glasses as needed. Keep chemicals and other potentially dangerous objects out of the reach of children. Reviewed by: Steven Dowshen, ... (Conjunctivitis) Eyes Corneal Abrasions Styes Activity: Eyes ...

  17. Superposition-model analysis of rare-earth doped BaY2F8

    Science.gov (United States)

    Magnani, N.; Amoretti, G.; Baraldi, A.; Capelletti, R.

    The energy level schemes of four rare-earth dopants (Ce3+ , Nd3+ , Dy3+ , and Er3+) in BaY2 F-8 , as determined by optical absorption spectra, were fitted with a single-ion Hamiltonian and analysed within Newman's Superposition Model for the crystal field. A unified picture for the four dopants was obtained, by assuming a distortion of the F- ligand cage around the RE site; within the framework of the Superposition Model, this distortion is found to have a marked anisotropic behaviour for heavy rare earths, while it turns into an isotropic expansion of the nearest-neighbours polyhedron for light rare earths. It is also inferred that the substituting ion may occupy an off-center position with respect to the original Y3+ site in the crystal.

  18. Noise-based logic: Binary, multi-valued, or fuzzy, with optional superposition of logic states

    CERN Document Server

    Kish, Laszlo B

    2008-01-01

    A new type of deterministic (non-probabilistic) computer logic system inspired by the stochasticity of brain signals is shown. The distinct values are represented by independent stochastic processes: independent voltage (or current) noises. The orthogonality of these processes provides a natural way to construct binary or multi-valued logic circuitry with arbitrary number N of logic values by using analog circuitry. Moreover, the logic values on a single wire can be made a (weighted) superposition of the N distinct logic values. Fuzzy logic is also naturally represented by a two-component superposition within the binary case (N=2). Error propagation and accumulation are suppressed. Other relevant advantages are reduced energy dissipation and leakage current problems, and robustness against circuit noise and background noises such as 1/f, Johnson, shot and crosstalk noise. Variability problems are also nonexistent because the logic value is an AC signal. A similar logic system can be built with orthogonal sinu...

  19. On Multiple Users Scheduling Using Superposition Coding over Rayleigh Fading Channels

    KAUST Repository

    Zafar, Ammar

    2013-02-20

    In this letter, numerical results are provided to analyze the gains of multiple users scheduling via superposition coding with successive interference cancellation in comparison with the conventional single user scheduling in Rayleigh blockfading broadcast channels. The information-theoretic optimal power, rate and decoding order allocation for the superposition coding scheme are considered and the corresponding histogram for the optimal number of scheduled users is evaluated. Results show that at optimality there is a high probability that only two or three users are scheduled per channel transmission block. Numerical results for the gains of multiple users scheduling in terms of the long term throughput under hard and proportional fairness as well as for fixed merit weights for the users are also provided. These results show that the performance gain of multiple users scheduling over single user scheduling increases when the total number of users in the network increases, and it can exceed 10% for high number of users

  20. Optical information encryption based on incoherent superposition with the help of the QR code

    Science.gov (United States)

    Qin, Yi; Gong, Qiong

    2014-01-01

    In this paper, a novel optical information encryption approach is proposed with the help of QR code. This method is based on the concept of incoherent superposition which we introduce for the first time. The information to be encrypted is first transformed into the corresponding QR code, and thereafter the QR code is further encrypted into two phase only masks analytically by use of the intensity superposition of two diffraction wave fields. The proposed method has several advantages over the previous interference-based method, such as a higher security level, a better robustness against noise attack, a more relaxed work condition, and so on. Numerical simulation results and actual smartphone collected results are shown to validate our proposal.

  1. Obtaining the Probability Vector Current Density in Canonical Quantum Mechanics by Linear Superposition

    CERN Document Server

    Kauffmann, Steven Kenneth

    2013-01-01

    The quantum mechanics status of the probability vector current density has long seemed to be marginal. On one hand no systematic prescription for its construction is provided, and the special examples of it that are obtained for particular types of Hamiltonian operator could conceivably be attributed to happenstance. On the other hand this concept's key physical interpretation as local average particle flux, which flows from the equation of continuity that it is supposed to satisfy in conjunction with the probability scalar density, has been claimed to breach the uncertainty principle. Given the dispiriting impact of that claim, we straightaway point out that the subtle directional nature of the uncertainty principle makes it consistent with the measurement of local average particle flux. We next focus on the fact that the unique closed-form linear-superposition quantization of any classical Hamiltonian function yields in tandem the corresponding unique linear-superposition closed-form divergence of the proba...

  2. NEAR-FIELD ACOUSTIC HOLOGRAPHY FOR SEMI-FREE ACOUSTIC FIELD BASED ON WAVE SUPERPOSITION APPROACH

    Institute of Scientific and Technical Information of China (English)

    LI Weibing; CHEN Jian; YU Fei; CHEN Xinzhao

    2006-01-01

    In the semi-free acoustic field, the actual acoustic pressure at any point is composed of two parts: The direct acoustic pressure and the reflected acoustic pressure. The general acoustic holographic theories and algorithms request that there is only the direct acoustic pressure contained in the pressure at any point on the hologram surface, consequently, they cannot be used to reconstruct acoustic source and predict acoustic field directly. To take the reflected pressure into consideration, near-field acoustic holography for semi-free acoustic field based on wave superposition approach is proposed to realize the holographic reconstruction and prediction of the semi-free acoustic field, and the wave superposition approach is adopted as a holographic transform algorithm. The proposed theory and algorithm are realized and verified with a numerical example,and the drawbacks of the general theories and algorithms in the holographic reconstruction and prediction of the semi-free acoustic field are also demonstrated by this numerical example.

  3. Quantum test of the equivalence principle for atoms in coherent superposition of internal energy states

    Science.gov (United States)

    Rosi, G.; D'Amico, G.; Cacciapuoti, L.; Sorrentino, F.; Prevedelli, M.; Zych, M.; Brukner, Č.; Tino, G. M.

    2017-06-01

    The Einstein equivalence principle (EEP) has a central role in the understanding of gravity and space-time. In its weak form, or weak equivalence principle (WEP), it directly implies equivalence between inertial and gravitational mass. Verifying this principle in a regime where the relevant properties of the test body must be described by quantum theory has profound implications. Here we report on a novel WEP test for atoms: a Bragg atom interferometer in a gravity gradiometer configuration compares the free fall of rubidium atoms prepared in two hyperfine states and in their coherent superposition. The use of the superposition state allows testing genuine quantum aspects of EEP with no classical analogue, which have remained completely unexplored so far. In addition, we measure the Eötvös ratio of atoms in two hyperfine levels with relative uncertainty in the low 10-9, improving previous results by almost two orders of magnitude.

  4. A numerical dressing method for the nonlinear superposition of solutions of the KdV equation

    Science.gov (United States)

    Trogdon, Thomas; Deconinck, Bernard

    2014-01-01

    In this paper we present the unification of two existing numerical methods for the construction of solutions of the Korteweg-de Vries (KdV) equation. The first method is used to solve the Cauchy initial-value problem on the line for rapidly decaying initial data. The second method is used to compute finite-genus solutions of the KdV equation. The combination of these numerical methods allows for the computation of exact solutions that are asymptotically (quasi-)periodic finite-gap solutions and are a nonlinear superposition of dispersive, soliton and (quasi-)periodic solutions in the finite (x, t)-plane. Such solutions are referred to as superposition solutions. We compute these solutions accurately for all values of x and t.

  5. Investigating macroscopic quantum superpositions and the quantum-to-classical transition by optical parametric amplification

    CERN Document Server

    De Martini, Francesco

    2012-01-01

    The present work reports on an extended research endeavor focused on the theoretical and experimental realization of a macroscopic quantum superposition (MQS) made up with photons. As it is well known, this intriguing, fundamental quantum condition is at the core of a famous argument conceived by Erwin Schroedinger, back in 1935. The main experimental challenge to the actual realization of this object resides generally on the unavoidable and uncontrolled interactions with the environment, i.e. the decoherence leading to the cancellation of any evidence of the quantum features associated with the macroscopic system. The present scheme is based on a nonlinear process, the "quantum injected optical parametric amplification", that maps by a linearized cloning process the quantum coherence of a single - particle state, i.e. a Micro - qubit, into a Macro - qubit, consisting in a large number M of photons in quantum superposition. Since the adopted scheme was found resilient to decoherence, the MQS\\ demonstration wa...

  6. A Defense of the Paraconsistent Approach to Quantum Superpositions (Answer to Arenhart and Krause)

    CERN Document Server

    de Ronde, Christian

    2014-01-01

    In (da Costa and de Ronde, 2014), Newton da Costa together with the author of this paper argued in favor of the possibility to consider quantum superpositions in terms of a paraconsistent approach. We claimed that, even though most interpretations of quantum mechanics attempt to escape contradictions, there are many hints that indicate it could be worth while to engage in a research of this kind. Recently, Arenhart and Krause (2014) have raised several arguments against this approach. In the present paper we attempt to answer the main questions presented by Arenhart and Krause. We will argue, firstly, that the obstacles presented by them are based on a specific metaphysical stance, which we will characterize in terms of what we call the Orthodox Line of Research (OLR). Secondly, that this is not necessarily the only possible line, and that a different one, namely, a Constructive Metaphysical Line of Research (CMLR) provides a different perspective in which the Paraconsistent Approach to Quantum Superpositions...

  7. More twists on optical twisters: of helico-conical beams, superpositions and combinations

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    nonseparable helical or azimuthal phase and the conical o r radial phase, and that have been shown to self-reconstruct after an obstruction . In this work, we deeanstruet the helico-conical beam (HCB) as a coherent superposition of Bessel-like beams, which carry arbitrary topological charge. Fromthis......-conical beam with seleetable number of multiple helix) as well as multihelical beams that emulate the diffractionfree properties of its constituent Bessel-like beams....

  8. Investigation of the Parametric Field from a Focusing Source by Using Superposition of Gaussian Beams

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dong; GONG Xiu-Fen; LU Rong-Rong

    2000-01-01

    The superposition method of Gaussian beams is extended to describe the acoustical parametric field from a focusing source. The axial sound pressure of the difference frequency wave 1MHz generated due to the interaction of two primary wave 3.5 and 4.5MHz is theoretically calculated by using 10 items of Gaussian functions. Experimental results coincide well with the calculated results except for the case at the vicinity of the focusing source.

  9. The superposition method in seeking the solitary wave solutions to the KdV-Burgers equation

    Indian Academy of Sciences (India)

    Yuanxi Xie; Jilashi Tang

    2006-03-01

    In this paper, starting from the careful analysis on the characteristics of the Burgers equation and the KdV equation as well as the KdV-Burgers equation, the superposition method is put forward for constructing the solitary wave solutions of the KdV-Burgers equation from those of the Burgers equation and the KdV equation. The solitary wave solutions for the KdV-Burgers equation are presented successfully by means of this method.

  10. Quantum Teleportation of One-Photon and Two-Photon Superposition States

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ One-photon and two-photon superposition states are the fundamental quantum states, which have shown interesting features, such as squeezing and anti-bunching. In this paper we discuss the quantum teleportation of such quantum states with the continuous-wave EPR states. Fidelity as a function of EPR correlation is obtained. We also compared the results with Fock state and coherent state teleportation.

  11. Measurement of the decoherence of a mesoscopic superposition of motional states of a trapped ion

    Institute of Scientific and Technical Information of China (English)

    Zheng Shi-Biao

    2004-01-01

    We propose a scheme to observe the decoherence of a mesoscopic superposition of two coherent states in the motion of a trapped ion. In the scheme the ion is excited by two perpendicular lasers tuned to the ion transition. The decoherence is revealed by the decrease of the correlation between two successive measurements of the internal state of the ion after relevant laser-ion interaction.

  12. External morphology, microstructure and light/dark adaptational changes of the compound eyes of Harmonia axyridis ab.conspicua( Coleoltera: Coccinellidae)%异色瓢虫显现变种复眼的形态、显微结构及其光暗条件下的适应性变化

    Institute of Scientific and Technical Information of China (English)

    吴春娟; 陈洁; 范凡; 秦秋菊; 何运转

    2011-01-01

    Compound eye is the main vision organ of insect, which plays a significant role in their foraging, finding mate and habitat, learning, memory and so on. In this study, the external morphology and internal microstructure of the compound eyes of Harmonia axyridis ab. Conspicua were observed by using scanning electron microscope and paraffin section. The results indicated that: ( 1 ) the compound eye is oval, and located on the lateral upside of the head. There is a nick on the compound eye, which is near to antennal socket. The surface of the ommatidia is smooth and not covered with corneal nipples. The compound eye of the female and male consists of 705 and 691 ommatidia, respectively. (2) The ommatidia located in the central region of the compound eye are typically hexagonal, while those located in the periphery of the compound eye are often of irregular, pentagonal, and even squarish shapes. (3) The ommatidium consists of corneal lens, crystalline cone, 8 retinula cells, rhabdom, basement membrane and pigment granules. The crystalline cone is composed of 4 cells. Among the 8 retinula cells, 6 cells are in the periphery and the other 2 are in the centre. (4) The microstructure of compound eye of H. Axyridis ab. Conspicua is significant different between dark and light adaptation. In light adaptation, most of the pigment granules are distributed between the crystalline cone and rhabdoms; the peripheral rhabdom is in ring form, and its inner and outer sides are covered with the pigment granules. In dark adaptation, the pigment granules move longitudinally and are distributed on the lateral upsides of the crystalline cone and rhabdoms; the peripheral rhabdoms twist appearing as irregular polygons, and only its outer sides are covered with the pigment granules. This study reveals that the compound eyes of H.Axyridis ab. Conspicua are of the type of apposition eye, and they adapt to the change of light and dark by the mechanism of pigment granules moving longitudinally

  13. Sagnac interferometry with coherent vortex superposition states in exciton-polariton condensates

    Science.gov (United States)

    Moxley, Frederick Ira; Dowling, Jonathan P.; Dai, Weizhong; Byrnes, Tim

    2016-05-01

    We investigate prospects of using counter-rotating vortex superposition states in nonequilibrium exciton-polariton Bose-Einstein condensates for the purposes of Sagnac interferometry. We first investigate the stability of vortex-antivortex superposition states, and show that they survive at steady state in a variety of configurations. Counter-rotating vortex superpositions are of potential interest to gyroscope and seismometer applications for detecting rotations. Methods of improving the sensitivity are investigated by targeting high momentum states via metastable condensation, and the application of periodic lattices. The sensitivity of the polariton gyroscope is compared to its optical and atomic counterparts. Due to the large interferometer areas in optical systems and small de Broglie wavelengths for atomic BECs, the sensitivity per detected photon is found to be considerably less for the polariton gyroscope than with competing methods. However, polariton gyroscopes have an advantage over atomic BECs in a high signal-to-noise ratio, and have other practical advantages such as room-temperature operation, area independence, and robust design. We estimate that the final sensitivities including signal-to-noise aspects are competitive with existing methods.

  14. Quantum State Engineering by Superpositions of Coherent States along aStraight Line in Cavity Quantum Electrodynamics

    Institute of Scientific and Technical Information of China (English)

    郑仕标

    2001-01-01

    A scheme is proposed for generating the superpositions of several coherent states in a cavity field with dispersive cavity quantum electrodynamics (QED). In the scheme, a sequence of atoms interacts dispersively with the cavity field, connected with a microwave source, and is manipulated by classical fields, followed by state-selective measurements. In this way, the cavity field is collapsed onto a superposition of several coherent states along a straight line with controllable coefficients. This scheme provides the possibility for quantum state engineering via coherent-state superpositions along a straight line in cavity QED for the first time.

  15. Preparation of arbitrary n-particle d-dimensional superposition states using only single qubit operations and CNOT gates

    Institute of Scientific and Technical Information of China (English)

    Wang Yan-Hui; Fang Mao-Fa

    2004-01-01

    In this article, using only single qubit operation and a CNOT gate, we propose a scheme for creating arbitrary n-particle d-dimensional superposition states including entangled states and give the relevant circuits for realizing this scheme.

  16. Eye Drop Tips

    Science.gov (United States)

    ... Involved News About Us Donate In This Section Eye Drop Tips en Español email Send this article ... the reach of children. Steps For Putting In Eye Drops: Start by tilting your head backward while ...

  17. What Is Dry Eye?

    Medline Plus

    Full Text Available ... information about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a ... the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media ...

  18. What Is Dry Eye?

    Medline Plus

    Full Text Available ... is also when your eyes do not make the right type of tears. How do tears work? ... you blink, a film of tears spreads over the eye. This keeps the eye’s surface smooth and ...

  19. What Is Dry Eye?

    Medline Plus

    Full Text Available ... tissue covering the white of your eye and inside your eyelids. Normally, our eyes constantly make tears ... Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  20. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Eye ... What Is Dry Eye? Leer en Español: ¿Qué ...

  1. TUBERCULOSIS AND THE EYE

    African Journals Online (AJOL)

    Key words: Mycobacteria; Tuberculosis; Eye ... of tuberculous eye disease or ocular tuberculosis has also been raised. Ocular ... patients with ocular complaints, compiled in an area ..... tuberculomas are usually solitary and may measure up.

  2. About the Eye

    Medline Plus

    Full Text Available ... you see. Check out the diagrams below to learn about each part of your eye and what ... the optic nerve to the brain. Watch now! Learn how the different parts of your eye work ...

  3. About the Eye

    Medline Plus

    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid ... Your eyes are made up of many different parts that work together to help you see. Check out the ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... about eye health and preserving your vision. Privacy Policy Related New Dry Eye Treatment is a Tear- ... Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of Service For Advertisers For Media Ophthalmology ...

  5. Preventing eye injuries

    Directory of Open Access Journals (Sweden)

    Daksha Patel

    2016-01-01

    Full Text Available The main challenge in developing a strategy to prevent eye injuries is that there are so many different causes and situations that can lead to eye injuries, each requiring a different approach.

  6. Common Eye Disorders

    Science.gov (United States)

    ... www.cdc.gov/emailupdates/">What's this? Submit Button Common Eye Disorders Recommend on Facebook Tweet Share Compartir ... macular degeneration, cataract, diabetic retinopathy, and glaucoma. Other common eye disorders include amblyopia and strabismus. For a ...

  7. The all seeing eye?

    NARCIS (Netherlands)

    Koenderink, Jan J.

    2014-01-01

    The All Seeing Eye? Did you know that you are probably a believer in the All Seeing Eye? The odds are that I’m right—why? Well, the bulk of mainstream vision literature blindly relies on the All Seeing Eye. It is written all over papers, albeit between the lines. Understandably so, for scientists re

  8. About the Eye

    Medline Plus

    Full Text Available ... other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health ... Eye Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and ...

  9. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye Health / Eye Health A-Z Dry Eye ... when I sleep? Feb 10, 2016 Leer en Español: ¿Qué Es el Ojo Seco? Find an Ophthalmologist ...

  10. About the Eye

    Medline Plus

    Full Text Available ... other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health ... Eye Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and ...

  11. The all seeing eye?

    NARCIS (Netherlands)

    Koenderink, Jan J.|info:eu-repo/dai/nl/070864543

    2014-01-01

    The All Seeing Eye? Did you know that you are probably a believer in the All Seeing Eye? The odds are that I’m right—why? Well, the bulk of mainstream vision literature blindly relies on the All Seeing Eye. It is written all over papers, albeit between the lines. Understandably so, for scientists

  12. Medicare Benefits and Your Eyes

    Science.gov (United States)

    ... Subscribe to eNews Close Donate Medicare Benefits & Your Eyes Eye Health is Important! As you age, your risk ... that you need. Ask about eye exams! Routine Eye Exams Medicare does not generally cover the costs ...

  13. Prevent Eye Injuries from Fireworks

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  14. Random array of colour filters in the eyes of butterflies

    NARCIS (Netherlands)

    Arikawa, K; Stavenga, DG

    1997-01-01

    The compound eye of the Japanese yellow swallowtail butterfly Papilio xuthus is not uniform, In a combined histological, electrophysiological and optical study, we found that the eye of P., xuthus has at least three different types of ommatidia, in a random distribution. In each ommatidium, nine

  15. Prediction in cases with superposition of different hydrological phenomena, such as from weather "cold drops

    Science.gov (United States)

    Anton, J. M.; Grau, J. B.; Tarquis, A. M.; Andina, D.; Sanchez, M. E.

    2012-04-01

    The authors have been involved in Model Codes for Construction prior to Eurocodes now Euronorms, and in a Drainage Instruction for Roads for Spain that adopted a prediction model from BPR (Bureau of Public Roads) of USA to take account of evident regional differences in Iberian Peninsula and Spanish Isles, and in some related studies. They used Extreme Value Type I (Gumbell law) models, with independent actions in superposition; this law was also adopted then to obtain maps of extreme rains by CEDEX. These methods could be extrapolated somehow with other extreme values distributions, but the first step was useful to set valid superposition schemas for actions in norms. As real case, in East of Spain rain comes usually extensively from normal weather perturbations, but in other cases from "cold drop" local high rains of about 400mm in a day occur, causing inundations and in cases local disasters. The city of Valencia in East of Spain was inundated at 1,5m high from a cold drop in 1957, and the river Turia formerly through that city was just later diverted some kilometers to South in a wider canal. With Gumbell law the expected intensity grows with time for occurrence, indicating a value for each given "return period", but the increasing speed grows with the "annual dispersion" of the Gumbell law, and some rare dangerous events may become really very possible in periods of many years. That can be proved with relatively simple models, e.g. with Extreme Law type I, and they could be made more precise or discussed. Such effects were used for superposition of actions on a structure for Model Codes, and may be combined with hydraulic effects, e.g. for bridges on rivers. These different Gumbell laws, or other extreme laws, with different dispersion may occur for marine actions of waves, earthquakes, tsunamis, and maybe for human perturbations, that could include industrial catastrophes, or civilization wars if considering historical periods.

  16. 3-D superposition for radiotherapy treatment planning using fast Fourier transforms.

    Science.gov (United States)

    Murray, D C; Hoban, P W; Metcalfe, P E; Round, W H

    1989-09-01

    Currently used radiotherapy treatment planning algorithms based on effective path length or scatter function methods do not model electron ranging from photon interaction sites. The superposition (or convolution) technique does model this effect, which is especially important at higher (linear accelerator) energies since the electron range is significant. Another advantage of this method is that it is conceptually simple and models the physical processes directly, rather than using empirically derived methods. A major disadvantage of superposition lies in the large amount of computer time required to generate a plan, especially in three dimensions. To help solve this problem, superposition using an invariant dose spread array (kernel) can be achieved by performing a convolution in Fourier space using fast Fourier transforms (FFTs). A method for 3 dimensional calculation of dose using FFTs is presented. Dose spread arrays are calculated using the EGS Monte Carlo code, and convolved with the TERMA (total energy released per unit mass). In both cases a 10 MV nominal beam energy is modelled by a 10 component spectrum, which is compared to the result obtained using monochromatic energy only (3.0 MeV at the surface). The FFT technique is shown to be significantly faster than standard convolution for medium to large TERMA and dose spread array sizes. The method is shown to be highly accurate for small fields in homogeneous media. For larger fields the central axis depth dose is accurate but the profile shape in the penumbral region becomes slightly distorted. This is because photons incident near the beam edges are not parallel to the cartesian coordinate system used as the convolution framework. However, this effect is sufficiently small to indicate that the convolution method is suitable for use in routine treatment planning.

  17. Implementation of FFT convolution and multigrid superposition models in the FOCUS RTP system

    Science.gov (United States)

    Miften, Moyed; Wiesmeyer, Mark; Monthofer, Suzanne; Krippner, Ken

    2000-04-01

    In radiotherapy treatment planning, convolution/superposition algorithms currently represent the best practical approach for accurate photon dose calculation in heterogeneous tissues. In this work, the implementation, accuracy and performance of the FFT convolution (FFTC) and multigrid superposition (MGS) algorithms are presented. The FFTC and MGS models use the same `TERMA' calculation and are commissioned using the same parameters. Both models use the same spectra, incorporate the same off-axis softening and base incident lateral fluence on the same measurements. In addition, corrections are explicitly applied to the polyenergetic and parallel kernel approximations, and electron contamination is modelled. Spectra generated by Monte Carlo (MC) modelling of treatment heads are used. Calculations using the MC spectra were in excellent agreement with measurements for many linear accelerator types. To speed up the calculations, a number of calculation techniques were implemented, including separate primary and scatter dose calculation, the FFT technique which assumes kernel invariance for the convolution calculation and a multigrid (MG) acceleration technique for the superposition calculation. Timing results show that the FFTC model is faster than MGS by a factor of 4 and 8 for small and large field sizes, respectively. Comparisons with measured data and BEAM MC results for a wide range of clinical beam setups show that (a) FFTC and MGS doses match measurements to better than 2% or 2 mm in homogeneous media; (b) MGS is more accurate than FFTC in lung phantoms where MGS doses are within 3% or 3 mm of BEAM results and (c) FFTC overestimates the dose in lung by a maximum of 9% compared to BEAM.

  18. The Superposition Principle in Quantum Mechanics - did the rock enter the foundation surreptitiously?

    CERN Document Server

    Dass, N D Hari

    2013-01-01

    The superposition principle forms the very backbone of quantum theory. The resulting linear structure of quantum theory is structurally so rigid that tampering with it may have serious, seemingly unphysical, consequences. This principle has been succesful at even the highest available accelerator energies. Is this aspect of quantum theory forever then? The present work is an attempt to understand the attitude of the founding fathers, particularly of Bohr and Dirac, towards this principle. The Heisenberg matrix mechanics on the one hand, and the Schrodinger wave mechanics on the other, are critically examined to shed light as to how this principle entered the very foundations of quantum theory.

  19. Strategies for reducing basis set superposition error (BSSE) in O/AU and O/Ni

    KAUST Repository

    Shuttleworth, I.G.

    2015-11-01

    © 2015 Elsevier Ltd. All rights reserved. The effect of basis set superposition error (BSSE) and effective strategies for the minimisation have been investigated using the SIESTA-LCAO DFT package. Variation of the energy shift parameter ΔEPAO has been shown to reduce BSSE for bulk Au and Ni and across their oxygenated surfaces. Alternative strategies based on either the expansion or contraction of the basis set have been shown to be ineffective in reducing BSSE. Comparison of the binding energies for the surface systems obtained using LCAO were compared with BSSE-free plane wave energies.

  20. Three-Phase Multiple Harmonic Sequence Detection Based on Generalized Delayed Signal Superposition

    DEFF Research Database (Denmark)

    Lu, Yong; Xiao, Guochun; Wang, Xiongfei

    2016-01-01

    -phase multiple harmonic sequence detection method is proposed for estimating both the fundamental and harmonic sequence components under adverse grid conditions. This detection method is denoted as MG DSS-PLL since it contains Multiple Generalized Delayed Signal Superposition operators and a Phase-Locked Loop....... The proposed MGDSS-PLL can be flexibly tuned to extracting any harmonic components according to specific applications and it also exhibits great robustness to different grid disturbances. Simulations and experimental results are presented for verifying the performance of the MGDSS-PLL....

  1. Superpositions of higher-order bessel beams and nondiffracting speckle fields

    CSIR Research Space (South Africa)

    Dudley, Angela L

    2009-08-01

    Full Text Available present in certain types of resonators. In optical tweezing, beams which carry orbital angular momentum are used to rotate trapped particles. In the case of generating a superposition of two higher-order Bessel beams which possess equal orders... but of differing sign, the Proc. of SPIE Vol. 7430 74300A-6 produced field carries no orbital angular momentum. However, these beams are still able to trap a particle in its intensity distribution and cause it to rotate over a spiral path along the beam’s...

  2. The accuracy of single-seed dose superposition for I-125 implants.

    Science.gov (United States)

    Burns, G S; Raeside, D E

    1989-01-01

    The Monte Carlo method was used to study perturbations of single I-125 seed dose distributions created by the presence of one or three neighboring seeds for the case of seeds immersed in a water phantom. Perturbation factors were determined within the geometric shadow of neighboring seeds for two-seed designs, four-seed spacings, and several choices of dose point. The results were compared to dose estimates obtained by the simple superposition of single-seed data for one- and two-plane implants. Some significant differences were found.

  3. Strong-Field Tunneling from a Coherent Superposition of Electronic States

    Science.gov (United States)

    Fechner, Lutz; Camus, Nicolas; Ullrich, Joachim; Pfeifer, Thomas; Moshammer, Robert

    2014-05-01

    Laser-induced tunnel ionization from a coherent superposition of electronic states in Ar+ is studied in a kinematically complete experiment. Within a pump-probe scheme a spin-orbit wave packet is launched through the first ionization step from the neutral species. The multielectron coherent wave packet is probed as a function of time by the second pulse which ionizes the system to Ar++. By measuring delay-dependent electron momentum distributions we directly image the evolution of the nonstationary multielectron wave function. Comparing the results with simulations we test common assumptions about electron momentum distributions and the tunneling process itself.

  4. Heisenberg-limited quantum sensing and metrology with superpositions of twin-Fock states

    Science.gov (United States)

    Gerry, Christopher C.; Mimih, Jihane

    2011-03-01

    We discuss the prospects of performing Heisenberg-limited quantum sensing and metrology using a Mach-Zehnder interferometer with input states that are superpositions of twin-Fock states and where photon number parity measurements are made on one of the output beams of the interferometer. This study is motivated by the experimental challenge of producing twin-Fock states on opposite sides of a beam splitter. We focus on the use of the so-called pair coherent states for this purpose and discuss a possible mechanism for generating them. We also discuss the prospect of using other superstitions of twin-Fock states, for the purpose of interferometry.

  5. Statistical Properties and Algebraic Characteristics of Quantum Superpositions of Negative Binomial States

    Institute of Scientific and Technical Information of China (English)

    WANG XiaoGuang; FU Hong-Chen

    2001-01-01

    We introduce new kinds of states of quantized radiation fields, which are the superpositions of negative binomial states. They exhibit remarkable nonclassical properties and reduce to Schrodinger cat states in a certain limit.The algebras involved in the even and odd negative binomial states turn out to be generally deformed oscillator algebras.It is found that the even and odd negative binomial states satisfy the same eigenvalue equation with the same eigenvalue and they can be viewed as two-photon nonlinear coherent states. Two methods of generating such the states are proposed.``

  6. Superposition model study of Cr3+ doped tetra methyl ammonium cadmium chloride.

    Science.gov (United States)

    Kripal, Ram; Yadav, Awadhesh Kumar

    2015-02-25

    The zero field splitting parameter D of Cr(3+) doped in tetra methyl ammonium cadmium chloride (TMCC) is calculated with perturbation formula using microscopic spin Hamiltonian theory and crystal field parameters from superposition model. The theoretically calculated ZFS parameter for Cr(3+) in TMCC single crystal is compared with the experimental value obtained by electron paramagnetic resonance (EPR). The local structure distortion is considered to obtain the crystal field parameters. The theoretical study gives the ZFS parameter D similar to that from experiment. However, calculation considering small distortion in local structure around Cr(3+) gives better agreement with the experimental value of ZFS parameter.

  7. A fillable micro-hollow sphere lesion detection phantom using superposition

    Energy Technology Data Exchange (ETDEWEB)

    DiFilippo, Frank P; Gallo, Sven L; Patel, Sagar [Department of Nuclear Medicine, Imaging Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Klatte, Ryan S [Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States)

    2010-09-21

    The lesion detection performance of SPECT and PET scanners is most commonly evaluated with a phantom containing hollow spheres in a background chamber at a specified radionuclide contrast ratio. However, there are limitations associated with a miniature version of a hollow sphere phantom for small-animal SPECT and PET scanners. One issue is that the 'wall effect' associated with zero activity in the sphere wall and fill port causes significant errors for small diameter spheres. Another issue is that there are practical difficulties in fabricating and in filling very small spheres (<3 mm diameter). The need for lesion detection performance assessment of small-animal scanners has motivated our development of a micro-hollow sphere phantom that utilizes the principle of superposition. The phantom is fabricated by stereolithography and has interchangeable sectors containing hollow spheres with volumes ranging from 1 to 14 {mu}L (diameters ranging from 1.25 to 3.0 mm). A simple 60{sup 0} internal rotation switches the positions of three such sectors with their corresponding background regions. Raw data from scans of each rotated configuration are combined and reconstructed to yield superposition images. Since the sphere counts and background counts are acquired separately, the wall effect is eliminated. The raw data are subsampled randomly prior to summation and reconstruction to specify the desired sphere-to-background contrast ratio of the superposition image. A set of images with multiple contrast ratios is generated for visual assessment of lesion detection thresholds. To demonstrate the utility of the phantom, data were acquired with a multi-pinhole SPECT/CT scanner. Micro-liter syringes were successful in filling the small hollow spheres, and the accuracy of the dispensed volume was validated through repeated filling and weighing of the spheres. The phantom's internal rotation and the data analysis process were successful in producing the expected

  8. Approximate eigensolutions of Dirac equation for the superposition Hellmann potential under spin and pseudospin symmetries

    Indian Academy of Sciences (India)

    M Hamzavi; S M Ikhdair

    2014-07-01

    The Hellmann potential is simply a superposition of an attractive Coulomb potential $−a/r$ plus a Yukawa potential e${}^{−δr} /r$. The generalized parametric Nikiforov–Uvarov (NU) method is used to examine the approximate analytical energy eigenvalues and two-component wave function of the Dirac equation with the Hellmann potential for arbitrary spin-orbit quantum number in the presence of exact spin and pseudospin (p-spin) symmetries. As a particular case, we obtain the energy eigenvalues of the pure Coulomb potential in the non-relativistic limit.

  9. Teleportation of a Coherent Superposition State Via a nonmaximally Entangled Coherent Xhannel

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ We investigate the problemm of teleportation of a superposition coherent state with nonmaximally entangled coherent channel. Two strategies are considered to complete the task. The first one uses entanglement concentration to purify the channel to a maximally entangled one. The second one teleports the state through the nonmaximally entangled coherent channel directly. We find that the probabilities of successful teleportations for the two strategies are depend on the amplitudes of the coherent states and the mean fidelity of teleportation using the first strategy is always less than that of the second strategy.

  10. EYE GAZE TRACKING

    DEFF Research Database (Denmark)

    2017-01-01

    This invention relates to a method of performing eye gaze tracking of at least one eye of a user, by determining the position of the center of the eye, said method comprising the steps of: detecting the position of at least three reflections on said eye, transforming said positions to spanning...... a normalized coordinate system spanning a frame of reference, wherein said transformation is performed based on a bilinear transformation or a non linear transformation e.g. a möbius transformation or a homographic transformation, detecting the position of said center of the eye relative to the position...... of said reflections and transforming this position to said normalized coordinate system, tracking the eye gaze by tracking the movement of said eye in said normalized coordinate system. Thereby calibration of a camera, such as knowledge of the exact position and zoom level of the camera, is avoided...

  11. A reflected wave superposition method for vibration and energy of a travelling string

    Science.gov (United States)

    Chen, E. W.; Luo, Q.; Ferguson, N. S.; Lu, Y. M.

    2017-07-01

    This paper considers the analytical free time domain response and energy in an axially translating and laterally vibrating string. The domain of the string is either a constant or variable length, dependent upon the general initial conditions. The translating tensioned strings possess either fixed-fixed or fixed-free boundaries. An alternative analytical solution using a reflected wave superposition method is presented for a finite translating string. Firstly, the cycles of vibration for both constant and variable length strings are provided, which for the latter are dependent upon the variable string length. Each cycle is divided into three time intervals according to the magnitude and the direction of the translating string velocity. Applying d'Alembert's method combined with the reflection properties, expressions for the reflected waves at the two boundaries are obtained. Subsequently, superposition of all of the incident and reflected waves provides results for the free vibration of the string over the three time intervals. The variation in the total mechanical energy of the string system is also shown. The accuracy and efficiency of the proposed method are confirmed numerically by comparison to simulations produced using a Newmark-Beta method solution and an existing state space function representation of the string dynamics.

  12. Phase sensitivity in deformed-state superposition considering nonlinear phase shifts

    Science.gov (United States)

    Berrada, K.

    2016-07-01

    We study the problem of the phase estimation for the deformation-state superposition (DSS) under perfect and lossy (due to a dissipative interaction of DSS with their environment) regimes. The study is also devoted to the phase enhancement of the quantum states resulting from a generalized non-linearity of the phase shifts, both without and with losses. We find that such a kind of superposition can give the smallest variance in the phase parameter in comparison with usual Schrödinger cat states in different order of non-linearity even if for a larger average number of photons. Due to the significance of how a system is quantum correlated with its environment in the construction of a scalable quantum computer, the entanglement between the DSS and its environment is investigated during the dissipation. We show that partial entanglement trapping occurs during the dynamics depending on the kind of deformation and mean photon number. These features make the DSS with a larger average number of photons a good candidate for implementation of schemes of quantum optics and information with high precision.

  13. A Simple Method on Generating any Bi-Photon Superposition State with Linear Optics

    Science.gov (United States)

    Zhang, Ting-Ting; Wei, Jie; Wang, Qin

    2017-04-01

    We present a simple method on the generation of any bi-photon superposition state using only linear optics. In this scheme, the input states, a two-mode squeezed state and a bi-photon state, meet on a beam-splitter and the output states are post-selected with two threshold single-photon detectors. We carry out corresponding numerical simulations by accounting for practical experimental conditions, calculating both the Wigner function and the state fidelity of those generated bi-photon superposition states. Our simulation results demonstrate that not only distinct nonclassical characteristics but also very high state fidelities can be achieved even under imperfect experimental conditions. Supported by the National Natural Science Foundation of China under Grant Nos. 61475197, 61590932, 11274178, the Natural Science Foundation of the Jiangsu Higher Education Institutions under Grant No. 15KJA120002, the Outstanding Youth Project of Jiangsu Province under Grant No. BK20150039, and the Priority Academic Program Development of Jiangsu Higher Education Institutions under Grant No. YX002001

  14. Biases on initial mass function determinations. II. Real multiple systems and chance superpositions

    CERN Document Server

    Apellániz, J Maíz

    2008-01-01

    When calculating IMFs for young clusters, one has to take into account that (a) most massive stars are born in multiple systems (b) most IMFs are derived from data that cannot resolve such systems, and (c) multiple chance superpositions between members are expected to happen if the cluster is too distant. In this article I use numerical experiments to model the consequences of those phenomena on the observed color-magnitude diagrams and the IMFs derived from them. Real multiple systems affect the observed or apparent massive-star MF slope little but can create a significant population of apparently ultramassive stars. Chance superpositions produce only small biases when the number of superimposed stars is low but, once a certain number threshold is reached, they can affect both the observed slope and the apparent stellar upper mass limit. I apply those experiments to two well known massive young clusters in the Local Group, NGC 3603 and R136. In both cases I show that the observed population of stars with mas...

  15. Teleportation of one ququat encoded in single mode superposition of coherent states

    CERN Document Server

    Prakash, Hari

    2012-01-01

    Superposition of optical coherent states (SCS) Ket(plus/minus alpha), possessing opposite phases, plays an important role as qubits in quantum information processing tasks like quantum computation, teleportation, cryptography etc. and are of fundamental importance in testing quantum mechanics. Recently, ququats and qutrits defined in four and three dimensional (D) Hilbert space, respectively, have attracted much more attention as they present advantage in secure quantum communication and also in researches on the foundation of quantum mechanics. Here, we show that superposition of four non-orthogonal coherent states Ket(plus/minus alpha) and Ket(plus/minus i alpha), that are 90 degrees out of phase, can be employed for encoding one ququat defined in a 4D Hilbert space spanned by four newly defined multi-photonic states, Ket(alpha subscript j) with 4n+j numbers of photons, where, j= 0, 1, 2, 3. We propose a scheme which generates states Ket(alpha subscript j). When these states fall on a 50-50 beam splitter, t...

  16. Superposition approach for description of electrical conductivity in sheared MWNT/polycarbonate melts

    Directory of Open Access Journals (Sweden)

    M. Saphiannikova

    2012-06-01

    Full Text Available The theoretical description of electrical properties of polymer melts, filled with attractively interacting conductive particles, represents a great challenge. Such filler particles tend to build a network-like structure which is very fragile and can be easily broken in a shear flow with shear rates of about 1 s–1. In this study, measured shear-induced changes in electrical conductivity of polymer composites are described using a superposition approach, in which the filler particles are separated into a highly conductive percolating and low conductive non-percolating phases. The latter is represented by separated well-dispersed filler particles. It is assumed that these phases determine the effective electrical properties of composites through a type of mixing rule involving the phase volume fractions. The conductivity of the percolating phase is described with the help of classical percolation theory, while the conductivity of non-percolating phase is given by the matrix conductivity enhanced by the presence of separate filler particles. The percolation theory is coupled with a kinetic equation for a scalar structural parameter which describes the current state of filler network under particular flow conditions. The superposition approach is applied to transient shear experiments carried out on polycarbonate composites filled with multi-wall carbon nanotubes.

  17. Propagation of the off-axis superposition of partially coherent beams through atmospheric turbulence

    Institute of Scientific and Technical Information of China (English)

    Zhang En-Tao; Ji Xiao-Ling; Lü Bai-Da

    2009-01-01

    The propagation properties of the off-axis superposition of partially coherent beams through atmospheric tur-bulence and their beam quality in terms of the mean-squared beam width w(z) and the power in the bucket (PIB)are studied in detail, where the effects of partial coherence, off-axis beam superposition and atmospheric turbulence are considered. The analytical expressions for the intensity, the beam width and the PIB are derived, and illustrative examples are given numerically. It is shown that the maximum intensity/max and the PIB decrease and ω(z) increases as the refraction index structure constant C2n increases. Therefore, the turbulence results in a degradation of the beam quality. However, the resulting partially coherent beam with a smaller value of spatial correlation parameter γ and larger values of separate distance Xd and beam number M is less affected by the turbulence than that with a larger value of γ and smaller values of xd and M. The main results obtained in this paper are explained physically.

  18. Risk evaluation of rock burst through theory of static and dynamic stresses superposition

    Institute of Scientific and Technical Information of China (English)

    李振雷; 蔡武; 窦林名; 何江; 王桂峰; 丁言露

    2015-01-01

    Rock burst is one of the most catastrophic dynamic hazards in coal mining. A static and dynamic stresses superposition-based (SDSS-based) risk evaluation method of rock burst was proposed to pre-evaluate rock burst risk. Theoretical basis of this method is the stress criterion incurring rock burst and rock burst risk is evaluated according to the closeness degree of the total stress (due to the superposition of static stress in the coal and dynamic stress induced by tremors) with the critical stress. In addition, risk evaluation criterion of rock burst was established by defining the “Satisfaction Degree” of static stress. Furthermore, the method was used to pre-evaluate rock burst risk degree and prejudge endangered area of an insular longwall face in Nanshan Coal Mine in China. Results show that rock burst risk is moderate at advance extent of 97 m, strong at advance extent of 97−131 m, and extremely strong (i.e. inevitable to occur) when advance extent exceeds 131 m (mining is prohibited in this case). The section of two gateways whose floor abuts 15−3 coal seam is a susceptible area prone to rock burst. Evaluation results were further compared with rock bursts and tremors detected by microseismic monitoring. Comparison results indicate that evaluation results are consistent with microseismic monitoring, which proves the method’s feasibility.

  19. Reconstruction of nonstationary sound fields based on the time domain plane wave superposition method.

    Science.gov (United States)

    Zhang, Xiao-Zheng; Thomas, Jean-Hugh; Bi, Chuan-Xing; Pascal, Jean-Claude

    2012-10-01

    A time-domain plane wave superposition method is proposed to reconstruct nonstationary sound fields. In this method, the sound field is expressed as a superposition of time convolutions between the estimated time-wavenumber spectrum of the sound pressure on a virtual source plane and the time-domain propagation kernel at each wavenumber. By discretizing the time convolutions directly, the reconstruction can be carried out iteratively in the time domain, thus providing the advantage of continuously reconstructing time-dependent pressure signals. In the reconstruction process, the Tikhonov regularization is introduced at each time step to obtain a relevant estimate of the time-wavenumber spectrum on the virtual source plane. Because the double infinite integral of the two-dimensional spatial Fourier transform is discretized directly in the wavenumber domain in the proposed method, it does not need to perform the two-dimensional spatial fast Fourier transform that is generally used in time domain holography and real-time near-field acoustic holography, and therefore it avoids some errors associated with the two-dimensional spatial fast Fourier transform in theory and makes possible to use an irregular microphone array. The feasibility of the proposed method is demonstrated by numerical simulations and an experiment with two speakers.

  20. The denoising of Monte Carlo dose distributions using convolution superposition calculations.

    Science.gov (United States)

    El Naqa, I; Cui, J; Lindsay, P; Olivera, G; Deasy, J O

    2007-09-07

    Monte Carlo (MC) dose calculations can be accurate but are also computationally intensive. In contrast, convolution superposition (CS) offers faster and smoother results but by making approximations. We investigated MC denoising techniques, which use available convolution superposition results and new noise filtering methods to guide and accelerate MC calculations. Two main approaches were developed to combine CS information with MC denoising. In the first approach, the denoising result is iteratively updated by adding the denoised residual difference between the result and the MC image. Multi-scale methods were used (wavelets or contourlets) for denoising the residual. The iterations are initialized by the CS data. In the second approach, we used a frequency splitting technique by quadrature filtering to combine low frequency components derived from MC simulations with high frequency components derived from CS components. The rationale is to take the scattering tails as well as dose levels in the high-dose region from the MC calculations, which presumably more accurately incorporates scatter; high-frequency details are taken from CS calculations. 3D Butterworth filters were used to design the quadrature filters. The methods were demonstrated using anonymized clinical lung and head and neck cases. The MC dose distributions were calculated by the open-source dose planning method MC code with varying noise levels. Our results indicate that the frequency-splitting technique for incorporating CS-guided MC denoising is promising in terms of computational efficiency and noise reduction.

  1. SAS-Pro: simultaneous residue assignment and structure superposition for protein structure alignment.

    Science.gov (United States)

    Shah, Shweta B; Sahinidis, Nikolaos V

    2012-01-01

    Protein structure alignment is the problem of determining an assignment between the amino-acid residues of two given proteins in a way that maximizes a measure of similarity between the two superimposed protein structures. By identifying geometric similarities, structure alignment algorithms provide critical insights into protein functional similarities. Existing structure alignment tools adopt a two-stage approach to structure alignment by decoupling and iterating between the assignment evaluation and structure superposition problems. We introduce a novel approach, SAS-Pro, which addresses the assignment evaluation and structure superposition simultaneously by formulating the alignment problem as a single bilevel optimization problem. The new formulation does not require the sequentiality constraints, thus generalizing the scope of the alignment methodology to include non-sequential protein alignments. We employ derivative-free optimization methodologies for searching for the global optimum of the highly nonlinear and non-differentiable RMSD function encountered in the proposed model. Alignments obtained with SAS-Pro have better RMSD values and larger lengths than those obtained from other alignment tools. For non-sequential alignment problems, SAS-Pro leads to alignments with high degree of similarity with known reference alignments. The source code of SAS-Pro is available for download at http://eudoxus.cheme.cmu.edu/saspro/SAS-Pro.html.

  2. The denoising of Monte Carlo dose distributions using convolution superposition calculations

    Energy Technology Data Exchange (ETDEWEB)

    El Naqa, I [Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO (United States); Cui, J [Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO (United States); Lindsay, P [MD Anderson, Houston, TX (United States); Olivera, G [Tomotherapy Inc., Madison, WI (United States); Deasy, J O [Department of Radiation Oncology, Washington University School of Medicine, St Louis, MO (United States)

    2007-09-07

    Monte Carlo (MC) dose calculations can be accurate but are also computationally intensive. In contrast, convolution superposition (CS) offers faster and smoother results but by making approximations. We investigated MC denoising techniques, which use available convolution superposition results and new noise filtering methods to guide and accelerate MC calculations. Two main approaches were developed to combine CS information with MC denoising. In the first approach, the denoising result is iteratively updated by adding the denoised residual difference between the result and the MC image. Multi-scale methods were used (wavelets or contourlets) for denoising the residual. The iterations are initialized by the CS data. In the second approach, we used a frequency splitting technique by quadrature filtering to combine low frequency components derived from MC simulations with high frequency components derived from CS components. The rationale is to take the scattering tails as well as dose levels in the high-dose region from the MC calculations, which presumably more accurately incorporates scatter; high-frequency details are taken from CS calculations. 3D Butterworth filters were used to design the quadrature filters. The methods were demonstrated using anonymized clinical lung and head and neck cases. The MC dose distributions were calculated by the open-source dose planning method MC code with varying noise levels. Our results indicate that the frequency-splitting technique for incorporating CS-guided MC denoising is promising in terms of computational efficiency and noise reduction. (note)

  3. NOTE: The denoising of Monte Carlo dose distributions using convolution superposition calculations

    Science.gov (United States)

    El Naqa, I.; Cui, J.; Lindsay, P.; Olivera, G.; Deasy, J. O.

    2007-09-01

    Monte Carlo (MC) dose calculations can be accurate but are also computationally intensive. In contrast, convolution superposition (CS) offers faster and smoother results but by making approximations. We investigated MC denoising techniques, which use available convolution superposition results and new noise filtering methods to guide and accelerate MC calculations. Two main approaches were developed to combine CS information with MC denoising. In the first approach, the denoising result is iteratively updated by adding the denoised residual difference between the result and the MC image. Multi-scale methods were used (wavelets or contourlets) for denoising the residual. The iterations are initialized by the CS data. In the second approach, we used a frequency splitting technique by quadrature filtering to combine low frequency components derived from MC simulations with high frequency components derived from CS components. The rationale is to take the scattering tails as well as dose levels in the high-dose region from the MC calculations, which presumably more accurately incorporates scatter; high-frequency details are taken from CS calculations. 3D Butterworth filters were used to design the quadrature filters. The methods were demonstrated using anonymized clinical lung and head and neck cases. The MC dose distributions were calculated by the open-source dose planning method MC code with varying noise levels. Our results indicate that the frequency-splitting technique for incorporating CS-guided MC denoising is promising in terms of computational efficiency and noise reduction.

  4. Teamwork for eye care

    Directory of Open Access Journals (Sweden)

    M Babar Qureshi

    2014-04-01

    Full Text Available Human resource development (HRD – the development of the people who deliver health care – has been identified as one of the key pillars of eye health delivery. HRD is one of the essential building blocks of the World Health Organization (WHO Global Action Plan: ‘Towards universal eye health’. The importance of HRD is also recognised beyond eye care, as can be seen in the WHO Health Systems approach.

  5. Personal Identification by Eyes

    OpenAIRE

    Marinović, Dunja; Čoklo, Miran; Njirić, Sanja; Mužić, Vedrana

    2011-01-01

    Identification of persons through the eyes is in the field of biometrical science. Many security systems are based on biometric methods of personal identification, to determine whether a person is presenting itself truly. The human eye contains an extremely large number of individual characteristics that make it particularly suitable for the process of identifying a person. Today, the eye is considered to be one of the most reliable body parts for human identification. Systems usi...

  6. Infrared Eye: Prototype 2

    Science.gov (United States)

    2016-06-07

    within the wide field and slaved to the operator’s line of sight by means of an eye- tracking system. The images from both cameras are fused and shown...simultaneously on a high resolution CRT display unit, interfaced with the eye- tracking unit in order to optimize the human-machine interface. The IR Eye...system was flight tested using the Advanced system Research Aircraft (Bell 412 helicopter) from the Flight Research Laboratory of the National Research

  7. The bright zone, a specialized dorsal eye region in the male blowfly Chrysomyia megacephala

    NARCIS (Netherlands)

    Hateren, J.H. van; Hardie, R.C.; Laughlin, S.B.; Stavenga, D.G.

    1989-01-01

    In the compound eye of the male Chrysomyia megacephala the facets in the ventral part of the eye are only ca. 20 µm in diameter, but increase abruptly to ca. 80 µm above the equator of the eye. Correspondingly there is a large and abrupt increase in the rhabdomere diameter from 2 to as much as 5 µm.

  8. The bright zone, a specialized dorsal eye region in the male blowfly Chrysomyia megacephala

    NARCIS (Netherlands)

    Hateren, J.H. van; Hardie, R.C.; Laughlin, S.B.; Stavenga, D.G.

    1989-01-01

    1. In the compound eye of the male Chrysomyia megacephala the facets in the ventral part of the eye are only ca. 20 µm in diameter, but increase abruptly to ca. 80 µm above the equator of the eye. Correspondingly there is a large and abrupt increase in the rhabdomere diameter from 2 to as much as 5

  9. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Academy Publications EyeNet Ophthalmology Ophthalmology Retina Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses Senior Ophthalmologists ...

  10. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics ... Services Advocacy Foundation About Subspecialties & More Eye ...

  11. Superposition of nonparaxial vectorial complex-source spherically focused beams: Axial Poynting singularity and reverse propagation

    Science.gov (United States)

    Mitri, F. G.

    2016-08-01

    In this work, counterintuitive effects such as the generation of an axial (i.e., long the direction of wave motion) zero-energy flux density (i.e., axial Poynting singularity) and reverse (i.e., negative) propagation of nonparaxial quasi-Gaussian electromagnetic (EM) beams are examined. Generalized analytical expressions for the EM field's components of a coherent superposition of two high-order quasi-Gaussian vortex beams of opposite handedness and different amplitudes are derived based on the complex-source-point method, stemming from Maxwell's vector equations and the Lorenz gauge condition. The general solutions exhibiting unusual effects satisfy the Helmholtz and Maxwell's equations. The EM beam components are characterized by nonzero integer degree and order (n ,m ) , respectively, an arbitrary waist w0, a diffraction convergence length known as the Rayleigh range zR, and a weighting (real) factor 0 ≤α ≤1 that describes the transition of the beam from a purely vortex (α =0 ) to a nonvortex (α =1 ) type. An attractive feature for this superposition is the description of strongly focused (or strongly divergent) wave fields. Computations of the EM power density as well as the linear and angular momentum density fluxes illustrate the analysis with particular emphasis on the polarization states of the vector potentials forming the beams and the weight of the coherent beam superposition causing the transition from the vortex to the nonvortex type. Should some conditions determined by the polarization state of the vector potentials and the beam parameters be met, an axial zero-energy flux density is predicted in addition to a negative retrograde propagation effect. Moreover, rotation reversal of the angular momentum flux density with respect to the beam handedness is anticipated, suggesting the possible generation of negative (left-handed) torques. The results are particularly useful in applications involving the design of strongly focused optical laser

  12. Multi-level manual and autonomous control superposition for intelligent telerobot

    Science.gov (United States)

    Hirai, Shigeoki; Sato, T.

    1989-01-01

    Space telerobots are recognized to require cooperation with human operators in various ways. Multi-level manual and autonomous control superposition in telerobot task execution is described. The object model, the structured master-slave manipulation system, and the motion understanding system are proposed to realize the concept. The object model offers interfaces for task level and object level human intervention. The structured master-slave manipulation system offers interfaces for motion level human intervention. The motion understanding system maintains the consistency of the knowledge through all the levels which supports the robot autonomy while accepting the human intervention. The superposing execution of the teleoperational task at multi-levels realizes intuitive and robust task execution for wide variety of objects and in changeful environment. The performance of several examples of operating chemical apparatuses is shown.

  13. A Simple Test of the Equivalence Principle(s) for Quantum Superpositions

    CERN Document Server

    Orlando, Patrick J; Modi, Kavan; Pollock, Felix A

    2015-01-01

    We propose a simple experimental test of the quantum equivalence principle introduced by Zych and Brukner [arXiv:1502.00971], which generalises the Einstein equivalence principle to superpositions of internal energy states. We consider a harmonically-trapped spin-$\\frac12$ atom in the presence of both gravity and an external magnetic field and show that when the external magnetic field is suddenly switched off, various violations of the equivalence principle would manifest as otherwise forbidden transitions. Performing such an experiment would put bounds on the various phenomenological violating parameters. We further demonstrate that the classical weak equivalence principle can be tested by suddenly putting the apparatus into free fall, effectively 'switching off' gravity.

  14. Quantum Interference and Superposition in Cognition: Development of a Theory for the Disjunction of Concepts

    CERN Document Server

    Aerts, Diederik

    2007-01-01

    We elaborate a theory for the modeling of concepts using the mathematical structure of quantum mechanics. Items and concepts are represented by vectors in the complex Hilbert space of quantum mechanics and membership weights of items are modeled by quantum weights calculated following the quantum rules. We apply this theory to model the disjunction of concepts and show that the predictions of our theory for the membership weights of items with respect to the disjunction of concepts match with great accuracy the results of an experiment conducted by Hampton (1988b). It is the quantum effects of interference and superposition that are at the origin of the effects of overextension and underextension observed by Hampton as deviations from a classical use of the disjunction. We show that the complex numbers of the Hilbert space are essential to obtaining the experimental predictions, i.e. vector space models over real numbers do not provide predictions matching the experimental data. We put forward an explanation ...

  15. Macroscopic realism, wave-particle duality and the superposition principle for entangled states

    CERN Document Server

    Chuprikov, N L

    2006-01-01

    On the basis of our model of a one-dimensional (1D) completed scattering (Russian Physics, 49, p.119 and p.314 (2006)) we argue that the linear formalism of quantum mechanics (QM) respects the principles of the macroscopic realism (J. Phys.: Condens. Matter, 14, R415-R451 (2002)). In QM one has to distinguish two kinds of pure ensembles: pure unentangled ensembles to be macroscopically inseparable, and pure entangled ones to be macroscopically separable. A pure entangled ensemble is an intermediate link between a pure unentangled ensemble and classical mixture. Like the former it strictly respects the linear formalism of QM. Like the latter it is decomposable into macroscopically distinct subensembles, in spite of interference between them; our new model exemplifies how to perform such a decomposition in the case of a 1D completed scattering. To respect macroscopic realism, the superposition principle must be reformulated: it must forbid introducing observables for entangled states.

  16. From Quantum To Classical Dynamics: A Landau Continuous Phase Transition With Spontaneous Superposition Breaking

    CERN Document Server

    Pankovic, V; Predojevic, M; Krmar, M; Pankovic, Vladan; Hubsch, Tristan; Predojevic, Milan; Krmar, Miodrag

    2004-01-01

    Developing an earlier proposal (Ne'eman, Damnjanovic, etc), we show herein that there is a Landau continuous phase transition from the exact quantum dynamics to the effectively classical one, occurring via spontaneous superposition breaking (effective hiding), as a special case of the corresponding general formalism (Bernstein). Critical values of the order parameters for this transition are determined by Heisenberg's indeterminacy relations, change continuously, and are in excellent agreement with the recent and remarkable experiments with Bose condensation. It is also shown that such a phase transition can sucessfully model self-collapse (self-decoherence), as an effective classical phenomenon, on the measurement device. This then induces a relative collapse (relative decoherence) as an effective quantum phenomenon on the measured quantum object by measurement. We demonstrate this (including the case of Bose-Einstein condensation) in the well-known cases of the Stern-Gerlach spin measurement, Bell's inequal...

  17. Numerical model for macroscopic quantum superpositions based on phase-covariant quantum cloning

    CERN Document Server

    Buraczewski, Adam

    2011-01-01

    We present a numerical model of macroscopic quantum superpositions generated by universally covariant optimal quantum cloning. It requires fast computation of the Gaussian hypergeometric function for moderate values of its parameters and argument as well as evaluation of infinite sums involving this function. We developed a method of dynamical estimation of cutoff for these sums. We worked out algorithms performing efficient summation of values of orders ranging from $10^{-100}$ to $10^{100}$ which neither lose precision nor accumulate errors, but provide the summation with acceleration. Our model is well adapted to experimental conditions. It optimizes computation by parallelization and choice of the most efficient algorithm. The methods presented here can be adjusted for analysis of similar experimental schemes. Including decoherence and realistic detection greatly improved the reliability and usability of our model for scientific research.

  18. On sparse reconstructions in near-field acoustic holography using the method of superposition

    CERN Document Server

    Abusag, Nadia M

    2016-01-01

    The method of superposition is proposed in combination with a sparse $\\ell_1$ optimisation algorithm with the aim of finding a sparse basis to accurately reconstruct the structural vibrations of a radiating object from a set of acoustic pressure values on a conformal surface in the near-field. The nature of the reconstructions generated by the method differs fundamentally from those generated via standard Tikhonov regularisation in terms of the level of sparsity in the distribution of charge strengths specifying the basis. In many cases, the $\\ell_1$ optimisation leads to a solution basis whose size is only a small fraction of the total number of measured data points. The effects of changing the wavenumber, the internal source surface and the (noisy) acoustic pressure data in general will all be studied with reference to a numerical study on a cuboid of similar dimensions to a typical loudspeaker cabinet. The development of sparse and accurate reconstructions has a number of advantageous consequences includin...

  19. Investigating the Influence of Visualization on Student Understanding of Quantum Superposition

    CERN Document Server

    Kohnle, Antje; Ruby, Scott

    2014-01-01

    Visualizations in interactive computer simulations are a powerful tool to help students develop productive mental models, particularly in the case of quantum phenomena that have no classical analogue. The QuVis Quantum Mechanics Visualization Project develops research-based interactive simulations for the learning and teaching of quantum mechanics. We describe efforts to refine the visual representation of a single-photon superposition state in the QuVis simulations. We developed various depictions of a photon incident on a beam splitter, and investigated their influence on student thinking through individual interviews. Outcomes from this study led to the incorporation of a revised visualization in all QuVis single-photon simulations. In-class trials in 2013 and 2014 using the Interferometer Experiments simulation in an introductory quantum physics course were used for a comparative study of the initial and revised visualizations. The class that used the revised visualization showed a lower frequency of inco...

  20. Effect of temperature on aging and time-temperature superposition in nonergodic laponite suspensions

    Science.gov (United States)

    Awasthi, Varun; Joshi, Yogesh M.

    We have studied the effect of temperature on aging dynamics of laponite suspensions by carrying out the rheological oscillatory and creep experiments. We observed that at higher temperatures the mechanism responsible for aging became faster thereby shifting the evolution of elastic modulus to lower ages. Significantly, in the creep experiments, all the aging time and the temperature dependent strain data superposed to form a master curve. Possibility of such superposition suggests that the rheological behavior depends on the temperature and the aging time only through the relaxation processes and both the variables do not affect the distribution but only the average value of relaxation times. In addition, this procedure allows us to predict long time rheological behavior by carrying out short time tests at high temperatures and small ages.

  1. Proportional fair scheduling with superposition coding in a cellular cooperative relay system

    DEFF Research Database (Denmark)

    Kaneko, Megumi; Hayashi, Kazunori; Popovski, Petar

    2013-01-01

    Many works have tackled on the problem of throughput and fairness optimization in cellular cooperative relaying systems. Considering firstly a two-user relay broadcast channel, we design a scheme based on superposition coding (SC) which maximizes the achievable sum-rate under a proportional...... fairness constraint. Unlike most relaying schemes where users are allocated orthogonally, our scheme serves the two users simultaneously on the same time-frequency resource unit by superposing their messages into three SC layers. The optimal power allocation parameters of each SC layer are derived...... by analysis. Next, we consider the general multi-user case in a cellular relay system, for which we design resource allocation algorithms based on proportional fair scheduling exploiting the proposed SC-based scheme. Numerical results show that the proposed algorithms allowing simultaneous user allocation...

  2. Superposition frames for adaptive time-frequency analysis and fast reconstruction

    CERN Document Server

    Rudoy, Daniel; Wolfe, Patrick J

    2009-01-01

    In this article we introduce a broad family of adaptive, linear time-frequency representations termed superposition frames, and show that they admit desirable fast overlap-add reconstruction properties akin to standard short-time Fourier techniques. This approach stands in contrast to many adaptive time-frequency representations in the extant literature, which, while more flexible than standard fixed-resolution approaches, typically fail to provide efficient reconstruction and often lack the regular structure necessary for precise frame-theoretic analysis. Our main technical contributions come through the development of properties which ensure that this construction provides for a numerically stable, invertible signal representation. Our primary algorithmic contributions come via the introduction and discussion of specific signal adaptation criteria in deterministic and stochastic settings, based respectively on time-frequency concentration and nonstationarity detection. We conclude with a short speech enhanc...

  3. Re-thinking the Rubric for Grading the CUE: The Superposition Principle

    CERN Document Server

    Zwolak, Justyna P; Manogue, Corinne A

    2013-01-01

    While introductory electricity and magnetism (E&M) has been investigated for decades, research at the upper-division is relatively new. The University of Colorado has developed the Colorado Upper-Division Electrostatics (CUE) Diagnostic to test students' understanding of the content of the first semester of an upper-division E&M course. While the questions on the CUE cover many learning goals in an appropriate manner, we believe the rubric for the CUE is particularly aligned to the topics and methods of teaching at the University of Colorado. We suggest that changes to the rubric would allow for better assessment of a wider range of teaching schemes. As an example, we highlight one problem from the CUE involving the superposition principle. Using data from both Oregon State University and the University of Colorado, we discuss the limitations of the current rubric, compare results using a different analysis scheme, and discuss the implications for assessing students' understanding.

  4. Accurate modeling of vector hysteresis using a superposition of Preisach-type models

    Energy Technology Data Exchange (ETDEWEB)

    Adly, A.A. [Cairo Univ., Giza (Egypt). Electrical Power and Machines Dept.; Mayergoyz, I.D. [Univ. of Maryland, College Park, MD (United States). Electrical Engineering Dept.

    1997-09-01

    Vector hysteresis models are basically regarded as helpful tools that can be utilized in simulating and/or predicting multi-dimensional field-media interactions. Simulations of energy loss in power devices having unoriented magnetic cores, read/write recording processes as well as tape and disk erasure approaches are examples of such interactions that are currently of considerable interest. Vector hysteresis models are generally regarded as helpful tools that can be utilized in simulating multi-dimensional field-media interactions. In this paper, simulation of vector hysteresis is proposed by using a superposition of isotropic Preisach-type models. This approach gives the opportunity to fully incorporate rotational experimental results in its identification procedure, thus leading to higher simulation accuracy. Detailed solution of the model identification problem and some experimental testing results are given in the paper.

  5. Similarity recognition of molecular structures by optimal atomic matching and rotational superposition.

    Science.gov (United States)

    Helmich, Benjamin; Sierka, Marek

    2012-01-15

    An algorithm for similarity recognition of molecules and molecular clusters is presented which also establishes the optimum matching among atoms of different structures. In the first step of the algorithm, a set of molecules are coarsely superimposed by transforming them into a common reference coordinate system. The optimum atomic matching among structures is then found with the help of the Hungarian algorithm. For this, pairs of structures are represented as complete bipartite graphs with a weight function that uses intermolecular atomic distances. In the final step, a rotational superposition method is applied using the optimum atomic matching found. This yields the minimum root mean square deviation of intermolecular atomic distances with respect to arbitrary rotation and translation of the molecules. Combined with an effective similarity prescreening method, our algorithm shows robustness and an effective quadratic scaling of computational time with the number of atoms.

  6. Color changes in wood during heating: kinetic analysis by applying a time-temperature superposition method

    Science.gov (United States)

    Matsuo, Miyuki; Yokoyama, Misao; Umemura, Kenji; Gril, Joseph; Yano, Ken'ichiro; Kawai, Shuichi

    2010-04-01

    This paper deals with the kinetics of the color properties of hinoki ( Chamaecyparis obtusa Endl.) wood. Specimens cut from the wood were heated at 90-180°C as accelerated aging treatment. The specimens completely dried and heated in the presence of oxygen allowed us to evaluate the effects of thermal oxidation on wood color change. Color properties measured by a spectrophotometer showed similar behavior irrespective of the treatment temperature with each time scale. Kinetic analysis using the time-temperature superposition principle, which uses the whole data set, was successfully applied to the color changes. The calculated values of the apparent activation energy in terms of L *, a *, b *, and Δ E^{*}_{ab} were 117, 95, 114, and 113 kJ/mol, respectively, which are similar to the values of the literature obtained for other properties such as the physical and mechanical properties of wood.

  7. EPR, optical and superposition model study of Mn2+ doped L+ glutamic acid

    Science.gov (United States)

    Kripal, Ram; Singh, Manju

    2015-12-01

    Electron paramagnetic resonance (EPR) study of Mn2+ doped L+ glutamic acid single crystal is done at room temperature. Four interstitial sites are observed and the spin Hamiltonian parameters are calculated with the help of large number of resonant lines for various angular positions of external magnetic field. The optical absorption study is also done at room temperature. The energy values for different orbital levels are calculated, and observed bands are assigned as transitions from 6A1g(s) ground state to various excited states. With the help of these assigned bands, Racah inter-electronic repulsion parameters B = 869 cm-1, C = 2080 cm-1 and cubic crystal field splitting parameter Dq = 730 cm-1 are calculated. Zero field splitting (ZFS) parameters D and E are calculated by the perturbation formulae and crystal field parameters obtained using superposition model. The calculated values of ZFS parameters are in good agreement with the experimental values obtained by EPR.

  8. Limitations to the validity of single wake superposition in wind farm yield assessment

    Science.gov (United States)

    Gunn, K.; Stock-Williams, C.; Burke, M.; Willden, R.; Vogel, C.; Hunter, W.; Stallard, T.; Robinson, N.; Schmidt, S. R.

    2016-09-01

    Commercially available wind yield assessment models rely on superposition of wakes calculated for isolated single turbines. These methods of wake simulation fail to account for emergent flow physics that may affect the behaviour of multiple turbines and their wakes and therefore wind farm yield predictions. In this paper wake-wake interaction is modelled computationally (CFD) and physically (in a hydraulic flume) to investigate physical causes of discrepancies between analytical modelling and simulations or measurements. Three effects, currently neglected in commercial models, are identified as being of importance: 1) when turbines are directly aligned, the combined wake is shortened relative to the single turbine wake; 2) when wakes are adjacent, each will be lengthened due to reduced mixing; and 3) the pressure field of downstream turbines can move and modify wakes flowing close to them.

  9. Role of externally induced coherent superposition in demonstrating quantum nonlocality in a correlated emission laser

    Energy Technology Data Exchange (ETDEWEB)

    Tesfa, Sintayehu [Physics Department, Addis Ababa University, PO Box 1176, Addis Ababa (Ethiopia); Physics Department, Dilla University, PO Box 419, Dilla (Ethiopia)], E-mail: sint_tesfa@yahoo.com

    2008-12-28

    Analysis of the effects of external pumping on the quantum features, including entanglement, quantum nonlocality and nonclassical photon number correlations, of the cavity radiation of a correlated emission laser is presented. It turns out that the contribution of externally induced coherent superposition in demonstrating quantum nonlocality is significant. Despite the available evidence that entangled states can exhibit nonlocality for certain values of the rate at which the atoms are injected into the cavity and amplitude of the driving radiation, a direct relation between the degree of entanglement and quantum nonlocality cannot be established. However, it seems likely to make a consistent connection between the Cauchy-Schwarz and Bell-Clauser-Horne-Shimony-Holt inequalities. It is evident that comparison among various nonclassical correlations enhances the understanding of the otherwise intricate quantum theoretical predictions.

  10. Photon-assisted Landau-Zener transition: Role of coherent superposition states

    CERN Document Server

    Sun, Zhe; Wang, Xiaoguang; Nori, Franco

    2012-01-01

    We investigate a Landau-Zener (LZ) transition process modelled by a quantum two-level system (TLS) coupled to a photon mode when the bias energy is varied linearly in time. The initial state of the photon field is assumed to be a superposition of coherent states, leading to a more intricate LZ transition. Applying the rotating-wave approximation (RWA), analytical results are obtained revealing the enhancement of the LZ probability by increasing the average photon number. We also consider the creation of entanglement and the change of photon statistics during the LZ process. When without the RWA, we find some qualitative differences of the LZ dynamics from the RWA results, e.g., the average photon number no longer monotonically enhances the LZ probability.

  11. A test of the equivalence principle(s) for quantum superpositions

    Science.gov (United States)

    Orlando, Patrick J.; Mann, Robert B.; Modi, Kavan; Pollock, Felix A.

    2016-10-01

    We propose an experimental test of the quantum equivalence principle introduced by Zych and Brukner (arXiv:1502.00971), which generalises the Einstein equivalence principle to superpositions of internal energy states. We consider a harmonically trapped {spin} - \\tfrac{1}{2} atom in the presence of both gravity and an external magnetic field and show that when the external magnetic field is suddenly switched off, various violations of the equivalence principle would manifest as otherwise forbidden transitions. Performing such an experiment would put bounds on the various phenomenological violating parameters. We further demonstrate that the classical weak equivalence principle can be tested by suddenly putting the apparatus into free fall, effectively ‘switching off’ gravity.

  12. Practical method using superposition of individual magnetic fields for initial arrangement of undulator magnets.

    Science.gov (United States)

    Tsuchiya, K; Shioya, T

    2015-04-01

    We have developed a practical method for determining an excellent initial arrangement of magnetic arrays for a pure-magnet Halbach-type undulator. In this method, the longitudinal magnetic field distribution of each magnet is measured using a moving Hall probe system along the beam axis with a high positional resolution. The initial arrangement of magnetic arrays is optimized and selected by analyzing the superposition of all distribution data in order to achieve adequate spectral quality for the undulator. We applied this method to two elliptically polarizing undulators (EPUs), called U#16-2 and U#02-2, at the Photon Factory storage ring (PF ring) in the High Energy Accelerator Research Organization (KEK). The measured field distribution of the undulator was demonstrated to be excellent for the initial arrangement of the magnet array, and this method saved a great deal of effort in adjusting the magnetic fields of EPUs.

  13. Digital coherent superposition of optical OFDM subcarrier pairs with Hermitian symmetry for phase noise mitigation.

    Science.gov (United States)

    Yi, Xingwen; Chen, Xuemei; Sharma, Dinesh; Li, Chao; Luo, Ming; Yang, Qi; Li, Zhaohui; Qiu, Kun

    2014-06-02

    Digital coherent superposition (DCS) provides an approach to combat fiber nonlinearities by trading off the spectrum efficiency. In analogy, we extend the concept of DCS to the optical OFDM subcarrier pairs with Hermitian symmetry to combat the linear and nonlinear phase noise. At the transmitter, we simply use a real-valued OFDM signal to drive a Mach-Zehnder (MZ) intensity modulator biased at the null point and the so-generated OFDM signal is Hermitian in the frequency domain. At receiver, after the conventional OFDM signal processing, we conduct DCS of the optical OFDM subcarrier pairs, which requires only conjugation and summation. We show that the inter-carrier-interference (ICI) due to phase noise can be reduced because of the Hermitain symmetry. In a simulation, this method improves the tolerance to the laser phase noise. In a nonlinear WDM transmission experiment, this method also achieves better performance under the influence of cross phase modulation (XPM).

  14. Superposition of two optical vortices with opposite integer or non-integer orbital angular momentum

    Directory of Open Access Journals (Sweden)

    Carlos Fernando Díaz Meza

    2016-04-01

    Full Text Available This work develops a brief proposal to achieve the superposition of two opposite vortex beams, both with integer or non-integer mean value of the orbital angular momentum. The first part is about the generation of this kind of spatial light distributions through a modified Brown and Lohmann’s hologram. The inclusion of a simple mathematical expression into the pixelated grid’s transmittance function, based in Fourier domain properties, shifts the diffraction orders counterclockwise and clockwise to the same point and allows the addition of different modes. The strategy is theoretically and experimentally validated for the case of two opposite rotation helical wavefronts.

  15. Enhancing quantum entanglement for continuous variables by a coherent superposition of photon subtraction and addition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su-Yong; Kim, Ho-Joon [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Ji, Se-Wan [School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-012 (Korea, Republic of); Nha, Hyunchul [Department of Physics, Texas A and M University at Qatar, P.O. Box 23874, Doha (Qatar); Institute fuer Quantenphysik, Universitaet Ulm, D-89069 Ulm (Germany)

    2011-07-15

    We investigate how the entanglement properties of a two-mode state can be improved by performing a coherent superposition operation ta+ra{sup {dagger}} of photon subtraction and addition, proposed by Lee and Nha [Phys. Rev. A 82, 053812 (2010)], on each mode. We show that the degree of entanglement, the Einstein-Podolsky-Rosen-type correlation, and the performance of quantum teleportation can be all enhanced for the output state when the coherent operation is applied to a two-mode squeezed state. The effects of the coherent operation are more prominent than those of the mere photon subtraction a and the addition a{sup {dagger}} particularly in the small-squeezing regime, whereas the optimal operation becomes the photon subtraction (case of r=0) in the large-squeezing regime.

  16. Eye proprioception may provide real time eye position information.

    Science.gov (United States)

    Wang, Jing; Pan, Yujun

    2013-03-01

    Because of the frequency of eye movements, online knowledge of eye position is crucial for the accurate spatial perception and behavioral navigation. Both the internal monitoring signal (corollary discharge) of eye movements and the eye proprioception signal are thought to contribute to the localization of the eye position in the orbit. However, the functional role of these two eye position signals in spatial cognition has been disputed for more than a century. The predominant view proposes that the online analysis of eye position is exclusively provided by the corollary discharge signal, while the eye proprioception signal only plays a role in the long-term calibration of the oculomotor system. However, increasing evidence from recent behavioral and physiological studies suggests that the eye proprioception signal may play a role in the online monitoring of eye position. The purpose of this review is to discuss the feasibility and possible function of the eye proprioceptive signal for online monitoring of eye position.

  17. Contradiction between assumption on superposition of flux-qubit states and the law of angular momentum conservation

    CERN Document Server

    Nikulov, A V

    2009-01-01

    Superconducting loop interrupted by one or three Josephson junctions is considered in many publications as a possible quantum bit, flux qubit, which can be used for creation of quantum computer. But the assumption on superposition of two macroscopically distinct quantum states of superconducting loop contradict to the fundamental law of angular momentum conservation and the universally recognized quantum formalism. Numerous publications devoted to the flux qubit testify to an inadequate interpretation by many authors of paradoxical nature of superposition principle and the subject of quantum description.

  18. Hidden Vacuum Rabi Oscillations: Dynamical Quantum Superpositions of On/Off Interaction between a Single Quantum Dot and a Microcavity

    Science.gov (United States)

    Ridolfo, A.; Stassi, R.; Di Stefano, O.

    2017-06-01

    We show that it is possible to realize quantum superpositions of switched-on and -off strong light-matter interaction in a single quantum dot- semiconductor microcavity system. Such superpositions enable the observation of counterintuitive quantum conditional dynamics effects. Situations are possible where cavity photons as well as the emitter luminescence display exponential decay but their joint detection probability exhibits vacuum Rabi oscillations. Remarkably, these quantum correlations are also present in the nonequilibrium steady state spectra of such coherently driven dissipative quantum systems.

  19. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive ... Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive ...

  20. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive Surgery Museum of Vision Subspecialties Cataract/ ... Deadlines Ophthalmology Job Center Our Sites EyeWiki International Society of Refractive Surgery Museum of Vision Subspecialties Cataract/ ...

  1. About the Eye

    Medline Plus

    Full Text Available ... NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the ...

  2. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Emergency Relief EyeCare America Help IRIS Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our ... Emergency Relief EyeCare America Help IRIS Registry Medicare Physician Payment Meetings and Deadlines Ophthalmology Job Center Our ...

  3. About the Eye

    Medline Plus

    Full Text Available ... Optical Illusions Printables About the Eye Your eyes are made up of many different parts that work ... Media Information in Spanish (Información en español) Website, ... Office of Science Communications, Public Liaison, and Education. Technical questions about ...

  4. Eye-Tracking

    Directory of Open Access Journals (Sweden)

    Gabriela GROSSECK

    2006-01-01

    Full Text Available Eye-tracking: one of the newest and most efficient methods of improving on-line marketing communication is called eye-tracking. Marketers have borrowed this technique, usually used in psychological and medical research, in order to study web users with the help of a video camera incorporated in the monitor.

  5. Perception of eye positions

    NARCIS (Netherlands)

    Lorteije, J.A.M.; Wezel, R.J.A. van; Lankheet, M.J.M.

    2002-01-01

    In a two-alternative forced-choice psychophysical test human subjects were tested for their ability to perceive their own viewing direction. A small red flash was presented at different horizontal positions left or right from the subjects' eye position on the screen. Eye positions were recorded with

  6. Understanding pink eye

    Science.gov (United States)

    Pink eye (PE) is a physiological tuber disorder that can result in serious processing complications and storage losses. The earliest external symptoms consist of an ephemeral pinkish discoloration around tuber eyes, predominately at the bud end of the tuber. These pinkish areas can then develop into...

  7. Photorefraction of the Eye

    Science.gov (United States)

    Colicchia, Giuseppe; Wiesner, Hartmut; Zollman, Dean

    2015-01-01

    Photorefraction is a method to easily estimate the refractive state of the eye. The principle of photorefraction involves projecting light into the eye during flash photography and then examining the paths of light that emerge from the pupil after scattering on the back portion of the interior of the eyeball (fundus). We will explain the optical…

  8. Eye tracking social preferences

    NARCIS (Netherlands)

    Jiang, Ting; Potters, Jan; Funaki, Yukihiko

    We hypothesize that if people are motivated by a particular social preference, then choosing in accordance with this preference will lead to an identifiable pattern of eye movements. We track eye movements while subjects make choices in simple three-person distribution experiments. We characterize

  9. BullsEye

    DEFF Research Database (Denmark)

    Klokmose, Clemens Nylandsted; Kristensen, Janus Bager; Bagge, Rolf

    2014-01-01

    implemented primarily in shaders on the GPU. The techniques are realized in the BullsEye computer vision software. We demonstrate experimentally that BullsEye provides sub-pixel accuracy down to a tenth of a pixel, which is a significant improvement compared to the commonly used reacTIVision software....

  10. Quantum control of electronic fluxes during adiabatic attosecond charge migration in degenerate superposition states of benzene

    Science.gov (United States)

    Jia, Dongming; Manz, Jörn; Paulus, Beate; Pohl, Vincent; Tremblay, Jean Christophe; Yang, Yonggang

    2017-01-01

    We design four linearly x- and y-polarized as well as circularly right (+) and left (-) polarized, resonant π / 2 -laser pulses that prepare the model benzene molecule in four different degenerate superposition states. These consist of equal (0.5) populations of the electronic ground state S0 (1A1g) plus one of four degenerate excited states, all of them accessible by dipole-allowed transitions. Specifically, for the molecule aligned in the xy-plane, these excited states include different complex-valued linear combinations of the 1E1u,x and 1E1u,y degenerate states. As a consequence, the laser pulses induce four different types of periodic adiabatic attosecond (as) charge migrations (AACM) in benzene, all with the same period, 504 as, but with four different types of angular fluxes. One of the characteristic differences of these fluxes are the two angles for zero fluxes, which appear as the instantaneous angular positions of the "source" and "sink" of two equivalent, or nearly equivalent branches of the fluxes which flow in pincer-type patterns from one molecular site (the "source") to the opposite one (the "sink"). These angles of zero fluxes are either fixed at the positions of two opposite carbon nuclei in the yz-symmetry plane, or at the centers of two opposite carbon-carbon bonds in the xz-symmetry plane, or the angles of zero fluxes rotate in angular forward (+) or backward (-) directions, respectively. As a resume, our quantum model simulations demonstrate quantum control of the electronic fluxes during AACM in degenerate superposition states, in the attosecond time domain, with the laser polarization as the key knob for control.

  11. Stochastic versus deterministic kernel-based superposition approaches for dose calculation of intensity-modulated arcs

    Science.gov (United States)

    Tang, Grace; Earl, Matthew A.; Luan, Shuang; Wang, Chao; Cao, Daliang; Yu, Cedric X.; Naqvi, Shahid A.

    2008-09-01

    Dose calculations for radiation arc therapy are traditionally performed by approximating continuous delivery arcs with multiple static beams. For 3D conformal arc treatments, the shape and weight variation per degree is usually small enough to allow arcs to be approximated by static beams separated by 5°-10°. But with intensity-modulated arc therapy (IMAT), the variation in shape and dose per degree can be large enough to require a finer angular spacing. With the increase in the number of beams, a deterministic dose calculation method, such as collapsed-cone convolution/superposition, will require proportionally longer computational times, which may not be practical clinically. We propose to use a homegrown Monte Carlo kernel-superposition technique (MCKS) to compute doses for rotational delivery. The IMAT plans were generated with 36 static beams, which were subsequently interpolated into finer angular intervals for dose calculation to mimic the continuous arc delivery. Since MCKS uses random sampling of photons, the dose computation time only increased insignificantly for the interpolated-static-beam plans that may involve up to 720 beams. Ten past IMRT cases were selected for this study. Each case took approximately 15-30 min to compute on a single CPU running Mac OS X using the MCKS method. The need for a finer beam spacing is dictated by how fast the beam weights and aperture shapes change between the adjacent static planning beam angles. MCKS, however, obviates the concern by allowing hundreds of beams to be calculated in practically the same time as for a few beams. For more than 43 beams, MCKS usually takes less CPU time than the collapsed-cone algorithm used by the Pinnacle3 planning system.

  12. Genetic mechanisms involved in the evolution of the cephalopod camera eye revealed by transcriptomic and developmental studies

    OpenAIRE

    Ogura Atsushi; Yoshida Masa-aki

    2011-01-01

    Abstract Background Coleoid cephalopods (squids and octopuses) have evolved a camera eye, the structure of which is very similar to that found in vertebrates and which is considered a classic example of convergent evolution. Other molluscs, however, possess mirror, pin-hole, or compound eyes, all of which differ from the camera eye in the degree of complexity of the eye structures and neurons participating in the visual circuit. Therefore, genes expressed in the cephalopod eye after divergenc...

  13. 基于ZEMAX的仿生DRA复眼阵列的仿真与分析%Simulation and Analysis of the Bionic DRA Compound Eyes Based on the ZEMAX Software

    Institute of Scientific and Technical Information of China (English)

    曹卫达; 唐军; 王晨光; 丁宇凯; 王飞; 翟超; 刘俊

    2014-01-01

    昆虫 DRA 区域复眼阵列可以接收天空偏振光,并将包含其中的偏振信息提取出来,使昆虫复眼具备导航的功能;根据生物解剖学得出的DRA复眼阵列结构,提出一种采用MEMS工艺制作的简化阵列结构,其体积小、质量轻、视角大,通过拼合可以实现180°天空区域的偏振信息的完整获取;并在ZEMAX中建立了DRA复眼阵列模型,通过仿真分析得出此DRA复眼阵列模型采用的材料及结构合理,可以用来检测天空光偏振分布模式(E-矢量分布模式)。%Compound array in the DRA area of insects can receive the polarized light in the sky and abstract its polarization information, which enable the insects to navigate. According to the structure of DRA compound array elicited from biological anatomy, we put forward a kind of simplified array architecture made by MEMS technology, which has small volume, light weight, large visual angle and can perfectly obtain the polarization information of the sky all through 180° by combination. Then, we build the model of DRA compound array in ZEMAX, and educe that the material and structure of the model of DRA compound array are reasonable and can be used to detect the polarization information of the sky light effectively.

  14. Functional analysis of the role of eyes absent and sine oculis in the developing eye of the cricket Gryllus bimaculatus.

    Science.gov (United States)

    Takagi, Akira; Kurita, Kazuki; Terasawa, Taiki; Nakamura, Taro; Bando, Tetsuya; Moriyama, Yoshiyuki; Mito, Taro; Noji, Sumihare; Ohuchi, Hideyo

    2012-02-01

    In the cricket Gryllus bimaculatus, a hemimetabolous insect, the compound eyes begin to form in the embryo and increase 5-6 fold in size during the postembryonic development of the nymphal stage. Retinal stem cells in the anteroventral proliferation zone (AVPZ) of the nymphal eye proliferate to increase retinal progenitors, which then differentiate to form new ommatidia in the anterior region of the eye. However, mechanisms underlying this type of eye formation have not been well elucidated yet. Here, we found that the homologues of the retinal determination transcription factor genes of eyes absent (eya) and sine oculis (so) are expressed during the cricket embryonic eye formation. eya is also expressed intensely in the AVPZ of the nymphal eye. To explore their functions, we performed knockdown by RNA interference (RNAi). Knockdown of Gb'eya resulted in loss of the embryonic eye. In the nymphal eye, RNAi against Gb'eya or Gb'so impaired retinal morphology by apparently transforming cornea structures into head cuticle. These results imply that Gb'eya and Gb'so are essential for the differentiation of the retinal progenitor cells and maintaining retinal structures during eye development.

  15. Aerodynamic Analysis of the Truss-Braced Wing Aircraft Using Vortex-Lattice Superposition Approach

    Science.gov (United States)

    Ting, Eric Bi-Wen; Reynolds, Kevin Wayne; Nguyen, Nhan T.; Totah, Joseph J.

    2014-01-01

    The SUGAR Truss-BracedWing (TBW) aircraft concept is a Boeing-developed N+3 aircraft configuration funded by NASA ARMD FixedWing Project. This future generation transport aircraft concept is designed to be aerodynamically efficient by employing a high aspect ratio wing design. The aspect ratio of the TBW is on the order of 14 which is significantly greater than those of current generation transport aircraft. This paper presents a recent aerodynamic analysis of the TBW aircraft using a conceptual vortex-lattice aerodynamic tool VORLAX and an aerodynamic superposition approach. Based on the underlying linear potential flow theory, the principle of aerodynamic superposition is leveraged to deal with the complex aerodynamic configuration of the TBW. By decomposing the full configuration of the TBW into individual aerodynamic lifting components, the total aerodynamic characteristics of the full configuration can be estimated from the contributions of the individual components. The aerodynamic superposition approach shows excellent agreement with CFD results computed by FUN3D, USM3D, and STAR-CCM+. XXXXX Demand for green aviation is expected to increase with the need for reduced environmental impact. Most large transports today operate within the best cruise L/D range of 18-20 using the conventional tube-and-wing design. This configuration has led to marginal improvements in aerodynamic efficiency over this past century, as aerodynamic improvements tend to be incremental. A big opportunity has been shown in recent years to significantly reduce structural weight or trim drag, hence improved energy efficiency, with the use of lightweight materials such as composites. The Boeing 787 transport is an example of a modern airframe design that employs lightweight structures. High aspect ratio wing design can provide another opportunity for further improvements in energy efficiency. Historically, the study of high aspect ratio wings has been intimately tied to the study of

  16. Personal identification by eyes.

    Science.gov (United States)

    Marinović, Dunja; Njirić, Sanja; Coklo, Miran; Muzić, Vedrana

    2011-09-01

    Identification of persons through the eyes is in the field of biometrical science. Many security systems are based on biometric methods of personal identification, to determine whether a person is presenting itself truly. The human eye contains an extremely large number of individual characteristics that make it particularly suitable for the process of identifying a person. Today, the eye is considered to be one of the most reliable body parts for human identification. Systems using iris recognition are among the most secure biometric systems.

  17. Magnetic eye tracking in mice.

    Science.gov (United States)

    Payne, Hannah L; Raymond, Jennifer L

    2017-09-05

    Eye movements provide insights about a wide range of brain functions, from sensorimotor integration to cognition; hence, the measurement of eye movements is an important tool in neuroscience research. We describe a method, based on magnetic sensing, for measuring eye movements in head-fixed and freely moving mice. A small magnet was surgically implanted on the eye, and changes in the magnet angle as the eye rotated were detected by a magnetic field sensor. Systematic testing demonstrated high resolution measurements of eye position of eye tracking offers several advantages over the well-established eye coil and video-oculography methods. Most notably, it provides the first method for reliable, high-resolution measurement of eye movements in freely moving mice, revealing increased eye movements and altered binocular coordination compared to head-fixed mice. Overall, magnetic eye tracking provides a lightweight, inexpensive, easily implemented, and high-resolution method suitable for a wide range of applications.

  18. What Is Dry Eye?

    Medline Plus

    Full Text Available ... vision in the morning? Jun 12, 2017 Can lupus affect my vision? May 27, 2017 Is stopping ... Answers Free Newsletter Get ophthalmologist-reviewed tips and information about eye health and preserving your vision. Privacy ...

  19. Anatomy of the Eye

    Science.gov (United States)

    ... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Anatomy of the Eye En Español Read in Chinese External (Extraocular) Anatomy Extraocular Muscles: There are six muscles that are ...

  20. Eye Disease and Development

    DEFF Research Database (Denmark)

    Andersen, Thomas Barnebeck; Dalgaard, Carl-Johan Lars; Selaya, Pablo

    This research advances the hypothesis that cross-country variation in the historical incidence of eye disease has influenced the current global distribution of per capita income. The theory is that pervasive eye disease diminished the incentive to accumulate skills, thereby delaying the fertility...... transition and the take-off to sustained economic growth. In order to estimate the influence from eye disease incidence empirically, we draw on an important fact from the field of epidemiology: Exposure to solar ultraviolet B radiation (UVB-R) is an underlying determinant of several forms of eye disease...... are robust to the inclusion of an extensive set of climate and geography controls. Moreover, using a global data set on economic activity for all terrestrial grid cells we show that the link between UVB-R and economic development survives the inclusion of country fixed effect....

  1. About the Eye

    Medline Plus

    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips ... addressed to the NEI Website Manager . Department of Health and Human Services | The National Institutes of Health | ...

  2. About the Eye

    Medline Plus

    Full Text Available ... Units Division of Epidemiology and Clinical Applications eyeGENE Research Directors Office Office of the Scientific Director Sheldon S. Miller, Ph.D., Scientific Director David ...

  3. About the Eye

    Medline Plus

    Full Text Available ... of visual function, preservation of sight, and the special health problems and requirements of the blind.” News & ... Emily Y. Chew, M.D., Deputy Clinical Director Education Programs National Eye Health Education Program (NEHEP) Diabetic ...

  4. Eyes, Bulging (Proptosis)

    Science.gov (United States)

    ... a disorder causing overactivity of the thyroid gland ( hyperthyroidism ). Bulging eyes are not the same as prominent ... or pain Whether the person has symptoms of hyperthyroidism, such as inability to tolerate heat, increased sweating, ...

  5. About the Eye

    Medline Plus

    Full Text Available ... The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips ... addressed to the NEI Website Manager . Department of Health and Human Services | The National Institutes of Health | ...

  6. What Is Dry Eye?

    Medline Plus

    Full Text Available ... How do tears work? When you blink, a film of tears spreads over the eye. This keeps the eye’s surface smooth and clear. The tear film is important for good vision. The tear film ...

  7. About the Eye

    Medline Plus

    Full Text Available ... about each part of your eye and what it does. Macula (MACK-yoo-luh) is the small, ... area of the retina needed for central vision. It contains the fovea. Lens is the clear part ...

  8. What Is Eye Cancer?

    Science.gov (United States)

    ... melanomas. Melanomas develop from pigment-making cells called melanocytes . When melanoma develops in the eye, it is ... cells make the same kind of pigment as melanocytes in the skin, so it’s not surprising that ...

  9. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Find an Ophthalmologist Advanced ...

  10. About the Eye

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    Full Text Available ... Units Division of Epidemiology and Clinical Applications eyeGENE Research Directors Office Office of the Scientific Director Sheldon S. ... Fellowships NEI Summer Intern Program Diversity In Vision Research & Ophthalmology (DIVRO) Student Training Programs To search for ...

  11. Sports and Your Eyes

    Science.gov (United States)

    ... may put you at high risk for eye injuries. Baseball Basketball Water Sports Boxing Hockey Paintball Racquetball Softball Squash Fencing Lacrosse Wrestling Football Golf Badminton Soccer Tennis Fishing Bicycling Gymnastics Track ...

  12. Diabetic Eye Problems

    Science.gov (United States)

    ... damage your eyes. The most common problem is diabetic retinopathy. It is a leading cause of blindness ... You need a healthy retina to see clearly. Diabetic retinopathy damages the tiny blood vessels inside your ...

  13. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses ...

  14. About the Eye

    Medline Plus

    Full Text Available ... NEI Women Scientists Advisory Committee (WSAC) Board of Scientific Counselors National Advisory Eye Council (NAEC) Donating to ... Grants and Funding Extramural Research Division of Extramural Science Programs Division of Extramural Activities Extramural Contacts NEI ...

  15. What Is Dry Eye?

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    Full Text Available ... Eye May 03, 2012 Follow The Academy Professionals: Education Guidelines News Multimedia Public & Patients: Contact Us About the Academy Jobs at the Academy Financial Relationships with Industry Medical ...

  16. The ageing eye

    African Journals Online (AJOL)

    2007-10-11

    Oct 11, 2007 ... With an increasing elderly population, age-related eye diseases are becoming the leading causes of ... and social health and overall quality of life. Enormous strides are ..... hip fractures, accidents and depression. Conclusion.

  17. Multimodal eye recognition

    Science.gov (United States)

    Zhou, Zhi; Du, Yingzi; Thomas, N. L.; Delp, Edward J., III

    2010-04-01

    Multimodal biometrics use more than one means of biometric identification to achieve higher recognition accuracy, since sometimes a unimodal biometric is not good enough used to do identification and classification. In this paper, we proposed a multimodal eye recognition system, which can obtain both iris and sclera patterns from one color eye image. Gabor filter and 1-D Log-Gabor filter algorithms have been applied as the iris recognition algorithms. In sclera recognition, we introduced automatic sclera segmentation, sclera pattern enhancement, sclera pattern template generation, and sclera pattern matching. We applied kernelbased matching score fusion to improve the performance of the eye recognition system. The experimental results show that the proposed eye recognition method can achieve better performance compared to unimodal biometric identification, and the accuracy of our proposed kernel-based matching score fusion method is higher than two classic linear matching score fusion methods: Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA).

  18. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Dry Eye Symptoms Related Ask an Ophthalmologist Answers Can a six-month dissolvable punctal plug be removed ... insert a permanent punctal plug? Sep 12, 2017 Can you explain why I have halos and blurry ...

  19. Eye Injuries in Construction

    Science.gov (United States)

    ... from a power tool (like a drill or wheel) , OR ! If your eye is cut or punctured : • ... CIO: CPWR, Suite 1000, 8484 Georgia Ave., Silver Spring, MD 20910. (Edward C. Sullivan is president of ...

  20. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  1. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide ... What Is Dry Eye? Written By: Kierstan Boyd ...

  2. About the Eye

    Medline Plus

    Full Text Available ... about each part of your eye and what it does. Macula (MACK-yoo-luh) is the small, ... area of the retina needed for central vision. It contains the fovea. Lens is the clear part ...

  3. Toxoplasmosis (and the Eye)

    Science.gov (United States)

    ... cat litter boxes, cat feces, sandboxes, and any insects exposed to cat feces (cockroaches, flies, etc.). Immunocompromised ... rash. Eye symptoms vary, but may include blurred vision or floaters during active disease. The diagnosis can ...

  4. About the Eye

    Medline Plus

    Full Text Available ... programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and ... Health Information Frequently asked questions ...

  5. Applied eye tracking research

    NARCIS (Netherlands)

    Jarodzka, Halszka

    2011-01-01

    Jarodzka, H. (2010, 12 November). Applied eye tracking research. Presentation and Labtour for Vereniging Gewone Leden in oprichting (VGL i.o.), Heerlen, The Netherlands: Open University of the Netherlands.

  6. Modern sports eye injuries.

    Science.gov (United States)

    Capão Filipe, J A; Rocha-Sousa, A; Falcão-Reis, F; Castro-Correia, J

    2003-11-01

    To determine the severity and long term sequelae of eye injuries caused by modern sports that could be responsible for significant ocular trauma in the future. Prospective observational study of 24 (25 eyes) athletes with sports related ocular injuries from health clubs, war games, adventure, radical and new types of soccer, presenting to an eye emergency department between 1992 and 2002 (10 years). Modern sports were responsible for 8.3% of the 288 total sports eye injuries reported. Squash (29.2%) was the most common cause, followed by paintball (20.8%) and motocross (16.6%). The most common diagnosis during the follow up period was retinal breaks (20%). 18 (75%) patients sustained a severe injury. The final visual acuity remained <20/100 in two paintball players. Ocular injuries resulting from modern sports are often severe. Adequate instruction of the participants in the games, proper use of eye protectors, and a routine complete ophthalmological examination after an eye trauma should be mandatory.

  7. Scatter correction for cone-beam computed tomography using self-adaptive scatter kernel superposition

    Institute of Scientific and Technical Information of China (English)

    XIE Shi-Peng; LUO Li-Min

    2012-01-01

    The authors propose a combined scatter reduction and correction method to improve image quality in cone beam computed tomography (CBCT).The scatter kernel superposition (SKS) method has been used occasionally in previous studies.However,this method differs in that a scatter detecting blocker (SDB) was used between the X-ray source and the tested object to model the self-adaptive scatter kernel.This study first evaluates the scatter kernel parameters using the SDB,and then isolates the scatter distribution based on the SKS.The quality of image can be improved by removing the scatter distribution.The results show that the method can effectively reduce the scatter artifacts,and increase the image quality.Our approach increases the image contrast and reduces the magnitude of cupping.The accuracy of the SKS technique can be significantly improved in our method by using a self-adaptive scatter kernel.This method is computationally efficient,easy to implement,and provides scatter correction using a single scan acquisition.

  8. Plane-wave superpositions defined by orthonormal scalar functions on two- and three-dimensional manifolds

    Science.gov (United States)

    Borzdov

    2000-04-01

    Vector plane-wave superpositions defined by a given set of orthonormal scalar functions on a two- or three-dimensional manifold-beam manifold-are treated. We present a technique for composing orthonormal beams and some other specific types of fields such as three-dimensional standing waves, moving and evolving whirls. It can be used for any linear fields, in particular, electromagnetic fields in complex media and elastic fields in crystals. For electromagnetic waves in an isotropic medium or free space, unique families of exact solutions of Maxwell's equations are obtained. The solutions are illustrated by calculating fields, energy densities, and energy fluxes of beams defined by the spherical harmonics. It is shown that the obtained results can be used for a transition from the plane-wave approximation to more accurate models of real incident beams in free-space techniques for characterizing complex media. A mathematical formalism convenient for the treatment of various beams defined by the spherical harmonics is presented.

  9. SUPERPOSE-An excel visual basic program for fracture modeling based on the stress superposition method

    Science.gov (United States)

    Ismail Ozkaya, Sait

    2014-03-01

    An Excel Visual Basic program, SUPERPOSE, is presented to predict the distribution, relative size and strike of tensile and shear fractures on anticlinal structures. The program is based on the concept of stress superposition; addition of curvature-related local tensile stress and regional far-field stress. The method accurately predicts fractures on many Middle East Oil Fields that were formed under a strike slip regime as duplexes, flower structures or inverted structures. The program operates on the Excel platform. The program reads the parameters and structural grid data from an Excel template and writes the results to the same template. The program has two routines to import structural grid data in the Eclipse and Zmap formats. The platform of SUPERPOSE is a single layer structural grid of a given cell size (e.g. 50×50 m). In the final output, a single tensile or two conjugate shear fractures are placed in each cell if fracturing criteria are satisfied; otherwise the cell is left blank. Strike of the representative fracture(s) is calculated and exact, but the length is an index of fracture porosity (fracture density×length×aperture) within that cell.

  10. A new optical image cryptosystem based on two-beam coherent superposition and unequal modulus decomposition

    Science.gov (United States)

    Chen, Linfei; Gao, Xiong; Chen, Xudong; He, Bingyu; Liu, Jingyu; Li, Dan

    2016-04-01

    In this paper, a new optical image cryptosystem is proposed based on two-beam coherent superposition and unequal modulus decomposition. Different from the equal modulus decomposition or unit vector decomposition, the proposed method applies common vector decomposition to accomplish encryption process. In the proposed method, the original image is firstly Fourier transformed and the complex function in spectrum domain will be obtained. The complex distribution is decomposed into two vector components with unequal amplitude and phase by the common vector decomposition method. Subsequently, the two components are modulated by two random phases and transformed from spectrum domain to spatial domain, and amplitude parts are extracted as encryption results and phase parts are extracted as private keys. The advantages of the proposed cryptosystem are: four different phase and amplitude information created by the method of common vector decomposition strengthens the security of the cryptosystem, and it fully solves the silhouette problem. Simulation results are presented to show the feasibility and the security of the proposed cryptosystem.

  11. A comparison between anisotropic analytical and multigrid superposition dose calculation algorithms in radiotherapy treatment planning.

    Science.gov (United States)

    Wu, Vincent W C; Tse, Teddy K H; Ho, Cola L M; Yeung, Eric C Y

    2013-01-01

    Monte Carlo (MC) simulation is currently the most accurate dose calculation algorithm in radiotherapy planning but requires relatively long processing time. Faster model-based algorithms such as the anisotropic analytical algorithm (AAA) by the Eclipse treatment planning system and multigrid superposition (MGS) by the XiO treatment planning system are 2 commonly used algorithms. This study compared AAA and MGS against MC, as the gold standard, on brain, nasopharynx, lung, and prostate cancer patients. Computed tomography of 6 patients of each cancer type was used. The same hypothetical treatment plan using the same machine and treatment prescription was computed for each case by each planning system using their respective dose calculation algorithm. The doses at reference points including (1) soft tissues only, (2) bones only, (3) air cavities only, (4) soft tissue-bone boundary (Soft/Bone), (5) soft tissue-air boundary (Soft/Air), and (6) bone-air boundary (Bone/Air), were measured and compared using the mean absolute percentage error (MAPE), which was a function of the percentage dose deviations from MC. Besides, the computation time of each treatment plan was recorded and compared. The MAPEs of MGS were significantly lower than AAA in all types of cancers (pplans was significantly lower than that of the MGS (palgorithms demonstrated dose deviations of less than 4.0% in most clinical cases and their performance was better in homogeneous tissues than at tissue boundaries. In general, MGS demonstrated relatively smaller dose deviations than AAA but required longer computation time.

  12. Multi-dimensional color image storage and retrieval for a normal arbitrary quantum superposition state

    Science.gov (United States)

    Li, Hai-Sheng; Zhu, Qingxin; Zhou, Ri-Gui; Song, Lan; Yang, Xing-jiang

    2014-04-01

    Multi-dimensional color image processing has two difficulties: One is that a large number of bits are needed to store multi-dimensional color images, such as, a three-dimensional color image of needs bits. The other one is that the efficiency or accuracy of image segmentation is not high enough for some images to be used in content-based image search. In order to solve the above problems, this paper proposes a new representation for multi-dimensional color image, called a -qubit normal arbitrary quantum superposition state (NAQSS), where qubits represent colors and coordinates of pixels (e.g., represent a three-dimensional color image of only using 30 qubits), and the remaining 1 qubit represents an image segmentation information to improve the accuracy of image segmentation. And then we design a general quantum circuit to create the NAQSS state in order to store a multi-dimensional color image in a quantum system and propose a quantum circuit simplification algorithm to reduce the number of the quantum gates of the general quantum circuit. Finally, different strategies to retrieve a whole image or the target sub-image of an image from a quantum system are studied, including Monte Carlo sampling and improved Grover's algorithm which can search out a coordinate of a target sub-image only running in where and are the numbers of pixels of an image and a target sub-image, respectively.

  13. Applicability condition of time-temperature superposition principle (TTSP) to a multi-phase system

    Science.gov (United States)

    Nakano, Takato

    2013-08-01

    The applicability condition of the time-temperature superposition principle (TTSP) to a multi-phase system is analytically discussed assuming a mixture law. It was concluded that the TTSP does not hold for a multi-phase system in general but does hold for a multi-component system in which some components have the same temperature dependence and the others have no temperature dependence. On the basis of the results, the application of the TTSP to plant materials such as wood and bamboo was examined using a mixture law and a stretched-exponential function having a characteristic relaxation time τ 0 and a stretching parameter β. Wood can be treated as a multi-phase system consisting of a framework (f) and matrix (m). In this case, it was expected that the TTSP holds for the matrix in the shorter time region t≪ τ 0 f under T T gm , where t and T g is a measurement time and the glass transition temperature, respectively.

  14. A geometry-based approach to determining time-temperature superposition shifts in aging experiments

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Amitesh

    2015-12-21

    A powerful way to expand the time and frequency range of material properties is through a method called time-temperature superposition (TTS). Traditionally, TTS has been applied to the dynamical mechanical and flow properties of thermo-rheologically simple materials, where a well-defined master curve can be objectively and accurately obtained by appropriate shifts of curves at different temperatures. However, TTS analysis can also be useful in many other situations where there is scatter in the data and where the principle holds only approximately. In such cases, shifting curves can become a subjective exercise and can often lead to significant errors in the long-term prediction. This mandates the need for an objective method of determining TTS shifts. Here, we adopt a method based on minimizing the “arc length” of the master curve, which is designed to work in situations where there is overlapping data at successive temperatures. We examine the accuracy of the method as a function of increasing noise in the data, and explore the effectiveness of data smoothing prior to TTS shifting. We validate the method using existing experimental data on the creep strain of an aramid fiber and the powder coarsening of an energetic material.

  15. Superposition of elliptic functions as solutions for a large number of nonlinear equations

    Energy Technology Data Exchange (ETDEWEB)

    Khare, Avinash [Raja Ramanna Fellow, Indian Institute of Science Education and Research (IISER), Pune 411021 (India); Saxena, Avadh [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-03-15

    For a large number of nonlinear equations, both discrete and continuum, we demonstrate a kind of linear superposition. We show that whenever a nonlinear equation admits solutions in terms of both Jacobi elliptic functions cn(x, m) and dn(x, m) with modulus m, then it also admits solutions in terms of their sum as well as difference. We have checked this in the case of several nonlinear equations such as the nonlinear Schrödinger equation, MKdV, a mixed KdV-MKdV system, a mixed quadratic-cubic nonlinear Schrödinger equation, the Ablowitz-Ladik equation, the saturable nonlinear Schrödinger equation, λϕ{sup 4}, the discrete MKdV as well as for several coupled field equations. Further, for a large number of nonlinear equations, we show that whenever a nonlinear equation admits a periodic solution in terms of dn{sup 2}(x, m), it also admits solutions in terms of dn {sup 2}(x,m)±√(m) cn (x,m) dn (x,m), even though cn(x, m)dn(x, m) is not a solution of these nonlinear equations. Finally, we also obtain superposed solutions of various forms for several coupled nonlinear equations.

  16. Probing the conductance superposition law in single-molecule circuits with parallel paths.

    Science.gov (United States)

    Vazquez, H; Skouta, R; Schneebeli, S; Kamenetska, M; Breslow, R; Venkataraman, L; Hybertsen, M S

    2012-10-01

    According to Kirchhoff's circuit laws, the net conductance of two parallel components in an electronic circuit is the sum of the individual conductances. However, when the circuit dimensions are comparable to the electronic phase coherence length, quantum interference effects play a critical role, as exemplified by the Aharonov-Bohm effect in metal rings. At the molecular scale, interference effects dramatically reduce the electron transfer rate through a meta-connected benzene ring when compared with a para-connected benzene ring. For longer conjugated and cross-conjugated molecules, destructive interference effects have been observed in the tunnelling conductance through molecular junctions. Here, we investigate the conductance superposition law for parallel components in single-molecule circuits, particularly the role of interference. We synthesize a series of molecular systems that contain either one backbone or two backbones in parallel, bonded together cofacially by a common linker on each end. Single-molecule conductance measurements and transport calculations based on density functional theory show that the conductance of a double-backbone molecular junction can be more than twice that of a single-backbone junction, providing clear evidence for constructive interference.

  17. Domain Superposition Technique for Free Vibration Analysis of Textile Composite Structures

    Directory of Open Access Journals (Sweden)

    W. G. Jiang

    2015-03-01

    Full Text Available Textile composites consist of interlaced tows, which are impregnated with a matrix material and then cured. The interlacing of the tows offers the potential for increased through-thickness strength compared to conventional laminated composites. However, one disadvantage of textile composites is the difficulty in predicting their performance due to the complex geometry of their internal architectures. Finite element analysis (FEA has become an effective means to predict the response of complex textile composite structures. When an attempt is made to perform a conventional FEA, one of the tough issues faced is how to deal with the topologically complex internal geometries. To overcome this difficult issue, a domain superposition technique (DST has been proposed to implement free vibration analysis of woven composite structures. The significant advantage of the DST over traditional FEA is that it does not need to directly deal with the likely degenerated resin-rich region, thus the DST model is much easier to establish. Numerical results show that DST predictions correlate excellently with traditional FEAs.

  18. Application of time-temperature superposition method in thermal aging life prediction of shipboard cables

    Institute of Scientific and Technical Information of China (English)

    DENG Wen-dong; CHEN Yi-yuan

    2014-01-01

    The life of shipboard cables will decrease due to the complex aging processes. In terms of the safety perspective, remaining life prediction of the cable is essential to maintain a reliable operation. In this paper, firstly, based on Arrhenius equation, residual life of new styrene-butadiene cable is calculated;result indicates that the degradation rate which changes with time is proportional to thermal temperature. Then second order dynamic model is adopted into the residual life prediction, combined with the time-temperature superposition method (TTSP), and a new residual life model is proposed. According to the accelerated thermal aging experiment data and Arrhenius equation, TTSP method demonstrates to be an efficient way for life prediction, and life at normal temperature can be estimated by this model. In order to monitor the state of styrene-butadiene cable more accurately, an improved residual life model based on equivalent environment temperature of cable is proposed, and life of cable under real operation is analyzed. Result indicates that this model is credible and reliable, and it provides an important theoretical base for residual life of cables.

  19. Quantum superposition of a single microwave photon in two different 'colour' states

    Science.gov (United States)

    Zakka-Bajjani, Eva; Nguyen, François; Lee, Minhyea; Vale, Leila R.; Simmonds, Raymond W.; Aumentado, José

    2011-08-01

    Fully controlled coherent coupling of arbitrary harmonic oscillators is an important tool for processing quantum information. Coupling between quantum harmonic oscillators has previously been demonstrated in several physical systems using a two-level system as a mediating element. Direct interaction at the quantum level has only recently been realized by means of resonant coupling between trapped ions. Here we implement a tunable direct coupling between the microwave harmonics of a superconducting resonator by means of parametric frequency conversion. We accomplish this by coupling the mode currents of two harmonics through a superconducting quantum interference device (SQUID) and modulating its flux at the difference (~7GHz) of the harmonic frequencies. We deterministically prepare a single-photon Fock state and coherently manipulate it between multiple modes, effectively controlling it in a superposition of two different 'colours'. This parametric interaction can be described as a beamsplitter-like operation that couples different frequency modes. As such, it could be used to implement linear optical quantum computing protocols on-chip.

  20. Examining the justification of superposition model of FePc ; A DMC study

    CERN Document Server

    Ichibha, Tom; Hongo, Kenta; Maezono, Ryo

    2016-01-01

    We have applied CASSCF-DMC to evaluate relative stabilities of the possible electronic configurations of an isolated FePc under $D_{4h}$ symmetry. It predicts $A_{2g}$ ground state, supporting preceding DFT studies,[J. Chem. Phys. 114, 9780 (2001), Appl. Phys. 95, 165 (2009), Phys. Rev. B 85, 235129 (2012)] with confidence overcoming the ambiguity about exchange-correlation (XC) functionals. By comparing DMC with several XC, we clarified the importance of the short range exchange to describe the relative stability. We examined why the predicted $A_{2g}$ is excluded from possible ground states in the recent ligand field based model.[J. Chem. Phys. 138, 244308 (2013)] Simplified assumptions made in the superposition model [Rep. Prog. Phys. 52, 699 (1989)] are identified to give unreasonably less energy gain for $A_{2g}$ when compared with the reality. The state is found to have possible reasons for the stabilization, reducing the occupations from an unstable anti-bonding orbital, preventing double occupancies i...

  1. An approximate method to acoustic radiation problems: element radiation superposition method

    Institute of Scientific and Technical Information of China (English)

    wANG Bin; TANG weilin; FAN Jun

    2008-01-01

    An approximate method is brought forward to predict the acoustic pressure based on the surface velocity.It is named Element Radiation Superposition Method(ERSM).The study finds that each element in Acoustic Transfer Vector(ATV)equals the acoustic pressure radiated by the corresponding surface element vibrating in unit velocity and other surface elements keep still.that is the acoustic pressure radiated by the corresponding baffled pistonvibrating in unit velocity.So,it utilizes the acoustic pressure radiated by a baffled piston to establish the transfer relationship between the surfaEe velocity and the acoustic pressure.The total acoustic pressure is obtained through summing up the products of the surface velocity and the transfer quantity.It adopts the regular baffle to fit the actual baffle in order to calculate the acoustic pressure radiated by the baffled piston.This approximate method has larger advantage in calculating speed and memory space than Boundary Element Method.Numerical simulations show that this approximate method is reasonable and feasible.

  2. Isolated attosecond pulses generation from coherent superposition state of helium ion in static electric fields and spatial nonhomogeneous fields

    Science.gov (United States)

    Liu, Hao; Zhang, Zhengzhong; Wu, Yangjiang; Jiang, Shicheng; Yu, Chao

    2016-09-01

    We present a systematic study of high-order harmonic generation (HHG) from helium ion with the initial state prepared as a coherent superposition of electronic ground state and an excited state. As a result, the conversion efficiency of the harmonic spectrum is significantly enhanced. When we add a static electric field in fundamental field, the supercontinuum region of the harmonic spectrum is distinctly extended and an isolated 100 as pulse can be generated. Moreover, we use a spatial nonhomogeneous field to increase the cutoff energy in high-order harmonic generation spectrum, which can be extended to about 700 eV, and an isolated 50 as pulse can be obtained directly by the superposition of the supercontinuum harmonics.

  3. R3D Align: global pairwise alignment of RNA 3D structures using local superpositions

    Science.gov (United States)

    Rahrig, Ryan R.; Leontis, Neocles B.; Zirbel, Craig L.

    2010-01-01

    Motivation: Comparing 3D structures of homologous RNA molecules yields information about sequence and structural variability. To compare large RNA 3D structures, accurate automatic comparison tools are needed. In this article, we introduce a new algorithm and web server to align large homologous RNA structures nucleotide by nucleotide using local superpositions that accommodate the flexibility of RNA molecules. Local alignments are merged to form a global alignment by employing a maximum clique algorithm on a specially defined graph that we call the ‘local alignment’ graph. Results: The algorithm is implemented in a program suite and web server called ‘R3D Align’. The R3D Align alignment of homologous 3D structures of 5S, 16S and 23S rRNA was compared to a high-quality hand alignment. A full comparison of the 16S alignment with the other state-of-the-art methods is also provided. The R3D Align program suite includes new diagnostic tools for the structural evaluation of RNA alignments. The R3D Align alignments were compared to those produced by other programs and were found to be the most accurate, in comparison with a high quality hand-crafted alignment and in conjunction with a series of other diagnostics presented. The number of aligned base pairs as well as measures of geometric similarity are used to evaluate the accuracy of the alignments. Availability: R3D Align is freely available through a web server http://rna.bgsu.edu/R3DAlign. The MATLAB source code of the program suite is also freely available for download at that location. Supplementary information: Supplementary data are available at Bioinformatics online. Contact: r-rahrig@onu.edu PMID:20929913

  4. Throughput Maximization for Cognitive Radio Networks Using Active Cooperation and Superposition Coding

    KAUST Repository

    Hamza, Doha

    2015-02-13

    We propose a three-message superposition coding scheme in a cognitive radio relay network exploiting active cooperation between primary and secondary users. The primary user is motivated to cooperate by substantial benefits it can reap from this access scenario. Specifically, the time resource is split into three transmission phases: The first two phases are dedicated to primary communication, while the third phase is for the secondary’s transmission. We formulate two throughput maximization problems for the secondary network subject to primary user rate constraints and per-node power constraints with respect to the time durations of primary transmission and the transmit power of the primary and the secondary users. The first throughput maximization problem assumes a partial power constraint such that the secondary power dedicated to primary cooperation, i.e. for the first two communication phases, is fixed apriori. In the second throughput maximization problem, a total power constraint is assumed over the three phases of communication. The two problems are difficult to solve analytically when the relaying channel gains are strictly greater than each other and strictly greater than the direct link channel gain. However, mathematically tractable lowerbound and upperbound solutions can be attained for the two problems. For both problems, by only using the lowerbound solution, we demonstrate significant throughput gains for both the primary and the secondary users through this active cooperation scheme. We find that most of the throughput gains come from minimizing the second phase transmission time since the secondary nodes assist the primary communication during this phase. Finally, we demonstrate the superiority of our proposed scheme compared to a number of reference schemes that include best relay selection, dual-hop routing, and an interference channel model.

  5. Investigating and improving introductory physics students’ understanding of the electric field and superposition principle

    Science.gov (United States)

    Li, Jing; Singh, Chandralekha

    2017-09-01

    We discuss an investigation of the difficulties that students in a university introductory physics course have with the electric field and superposition principle and how that research was used as a guide in the development and evaluation of a research-validated tutorial on these topics to help students learn these concepts better. The tutorial uses a guided enquiry-based approach to learning and involved an iterative process of development and evaluation. During its development, we obtained feedback both from physics instructors who regularly teach introductory physics in which these concepts are taught and from students for whom the tutorial is intended. The iterative process continued and the feedback was incorporated in the later versions of the tutorial until the researchers were satisfied with the performance of a diverse group of introductory physics students on the post-test after they worked on the tutorial in an individual one-on-one interview situation. Then the final version of the tutorial was administered in several sections of the university physics course after traditional instruction in relevant concepts. We discuss the performance of students in individual interviews and on the pre-test administered before the tutorial (but after traditional lecture-based instruction) and on the post-test administered after the tutorial. We also compare student performance in sections of the class in which students worked on the tutorial with other similar sections of the class in which students only learned via traditional instruction. We find that students performed significantly better in the sections of the class in which the tutorial was used compared to when students learned the material via only lecture-based instruction.

  6. Shrimps that pay attention: saccadic eye movements in stomatopod crustaceans.

    Science.gov (United States)

    Marshall, N J; Land, M F; Cronin, T W

    2014-01-01

    Discovering that a shrimp can flick its eyes over to a fish and follow up by tracking it or flicking back to observe something else implies a 'primate-like' awareness of the immediate environment that we do not normally associate with crustaceans. For several reasons, stomatopods (mantis shrimp) do not fit the general mould of their subphylum, and here we add saccadic, acquisitional eye movements to their repertoire of unusual visual capabilities. Optically, their apposition compound eyes contain an area of heightened acuity, in some ways similar to the fovea of vertebrate eyes. Using rapid eye movements of up to several hundred degrees per second, objects of interest are placed under the scrutiny of this area. While other arthropod species, including insects and spiders, are known to possess and use acute zones in similar saccadic gaze relocations, stomatopods are the only crustacean known with such abilities. Differences among species exist, generally reflecting both the eye size and lifestyle of the animal, with the larger-eyed more sedentary species producing slower saccades than the smaller-eyed, more active species. Possessing the ability to rapidly look at and assess objects is ecologically important for mantis shrimps, as their lifestyle is, by any standards, fast, furious and deadly.

  7. Elementary Green function as an integral superposition of Gaussian beams in inhomogeneous anisotropic layered structures in Cartesian coordinates

    Science.gov (United States)

    Červený, Vlastislav; Pšenčík, Ivan

    2017-08-01

    Integral superposition of Gaussian beams is a useful generalization of the standard ray theory. It removes some of the deficiencies of the ray theory like its failure to describe properly behaviour of waves in caustic regions. It also leads to a more efficient computation of seismic wavefields since it does not require the time-consuming two-point ray tracing. We present the formula for a high-frequency elementary Green function expressed in terms of the integral superposition of Gaussian beams for inhomogeneous, isotropic or anisotropic, layered structures, based on the dynamic ray tracing (DRT) in Cartesian coordinates. For the evaluation of the superposition formula, it is sufficient to solve the DRT in Cartesian coordinates just for the point-source initial conditions. Moreover, instead of seeking 3 × 3 paraxial matrices in Cartesian coordinates, it is sufficient to seek just 3 × 2 parts of these matrices. The presented formulae can be used for the computation of the elementary Green function corresponding to an arbitrary direct, multiply reflected/transmitted, unconverted or converted, independently propagating elementary wave of any of the three modes, P, S1 and S2. Receivers distributed along or in a vicinity of a target surface may be situated at an arbitrary part of the medium, including ray-theory shadow regions. The elementary Green function formula can be used as a basis for the computation of wavefields generated by various types of point sources (explosive, moment tensor).

  8. Influence of the superposition approximation on calculated effective dose rates from galactic cosmic rays at aerospace-related altitudes

    Science.gov (United States)

    Copeland, Kyle

    2015-07-01

    The superposition approximation was commonly employed in atmospheric nuclear transport modeling until recent years and is incorporated into flight dose calculation codes such as CARI-6 and EPCARD. The useful altitude range for this approximation is investigated using Monte Carlo transport techniques. CARI-7A simulates atmospheric radiation transport of elements H-Fe using a database of precalculated galactic cosmic radiation showers calculated with MCNPX 2.7.0 and is employed here to investigate the influence of the superposition approximation on effective dose rates, relative to full nuclear transport of galactic cosmic ray primary ions. Superposition is found to produce results less than 10% different from nuclear transport at current commercial and business aviation altitudes while underestimating dose rates at higher altitudes. The underestimate sometimes exceeds 20% at approximately 23 km and exceeds 40% at 50 km. Thus, programs employing this approximation should not be used to estimate doses or dose rates for high-altitude portions of the commercial space and near-space manned flights that are expected to begin soon.

  9. Java application for the superposition T-matrix code to study the optical properties of cosmic dust aggregates

    CERN Document Server

    Halder, P; Roy, P Deb; Das, H S

    2014-01-01

    In this paper, we report the development of a java application for the Superposition T-matrix code, JaSTA (Java Superposition T-matrix App), to study the light scattering properties of aggregate structures. It has been developed using Netbeans 7.1.2, which is a java integrated development environment (IDE). The JaSTA uses double precession superposition codes for multi-sphere clusters in random orientation developed by Mackowski and Mischenko (1996). It consists of a graphical user interface (GUI) in the front hand and a database of related data in the back hand. Both the interactive GUI and database package directly enable a user to model by self-monitoring respective input parameters (namely, wavelength, complex refractive indices, grain size, etc.) to study the related optical properties of cosmic dust (namely, extinction, polarization, etc.) instantly, i.e., with zero computational time. This increases the efficiency of the user. The database of JaSTA is now created for a few sets of input parameters with...

  10. Visual navigation in starfish: first evidence for the use of vision and eyes in starfish.

    Science.gov (United States)

    Garm, Anders; Nilsson, Dan-Eric

    2014-02-22

    Most known starfish species possess a compound eye at the tip of each arm, which, except for the lack of true optics, resembles an arthropod compound eye. Although these compound eyes have been known for about two centuries, no visually guided behaviour has ever been directly associated with their presence. There are indications that they are involved in negative phototaxis but this may also be governed by extraocular photoreceptors. Here, we show that the eyes of the coral-reef-associated starfish Linckia laevigata are slow and colour blind. The eyes are capable of true image formation although with low spatial resolution. Further, our behavioural experiments reveal that only specimens with intact eyes can navigate back to their reef habitat when displaced, demonstrating that this is a visually guided behaviour. This is, to our knowledge, the first report of a function of starfish compound eyes. We also show that the spectral sensitivity optimizes the contrast between the reef and the open ocean. Our results provide an example of an eye supporting only low-resolution vision, which is believed to be an essential stage in eye evolution, preceding the high-resolution vision required for detecting prey, predators and conspecifics.

  11. Glaucoma: Eye-to-Eye with Dr. Rachel Bishop

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Glaucoma Eye-to-Eye with Dr. Rachel Bishop Past ... nerves are pale and cupped—signs of advanced glaucoma. Yet the patient wasn't aware of any ...

  12. Through the creator's eyes

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Lahlou, Saadi

    2012-01-01

    of an adapted Subjective Evidence-Based Ethnography (SEBE). This methodology combines (a) obtaining first person audio-visual recordings of creative action with a miniature video-camera worn at eye-level, (b) accessing the subjective experience of the participant through a confrontation interview based...

  13. The Aging Eye

    Science.gov (United States)

    ... and Tips Watch, Listen, and Learn Social Media ¡Ojo con su visión! ¡Ojo con su visión! Learn About Eye Disease Among Hispanics/Latinos ¡Ojo con su visión! Toolkits Resources Outreach Tools and ...

  14. An eye for inspiration

    Science.gov (United States)

    2009-11-01

    The discovery that the eye of a particular mantis shrimp has an achromatic quarter-waveplate that is superior to modern-day devices could be a source of inspiration to those designing optical components. Nature Photonics spoke to Nicholas Roberts, one of the researchers involved in the study.

  15. About the Eye

    Medline Plus

    Full Text Available ... of Health (NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information ... and what it does. Macula (MACK-yoo-luh) is the small, sensitive area of the retina needed ...

  16. King and Eye

    DEFF Research Database (Denmark)

    Suwannakij, Sing

    devices, most significantly the photographic and the cine cameras, but also encompassing other ocular apparatuses. The images produced through the contraptions were brought together under the royal eye at the apex, which in turn claimed its supremacy over space, time, and the vast and diverse population...

  17. [Eye and the pregnacy].

    Science.gov (United States)

    Dima, Anne Marie

    2012-01-01

    Pregnancy is associated with changes in many organs and systems including the eyes. Sometimes in pregnancy may appear physiological and pathological ocular changes that may be associated with pre-existing problems. In such cases it is very important interdisciplinary collaboration gynecologist, ophthalmologist.

  18. Eyes for Learning

    Science.gov (United States)

    Orfield, Antonia

    2008-01-01

    Vision is the dominant sense, and the eyes are connected with almost every other part of the brain. If the vision system is poorly developed, children trying to learn suffer. Without good up close vision, students are handicapped even if no one knows or suspects it--they may not even know it themselves. Students do not know that the way they see…

  19. About the Eye

    Medline Plus

    Full Text Available ... NIH), the National Eye Institute’s mission is to “conduct and support research, training, health information dissemination, and ... carry visual messages from the retina to the brain. Retina (REH-tin-uh) is the light-sensitive ...

  20. About the Eye

    Medline Plus

    Full Text Available ... of Epidemiology and Clinical Applications eyeGENE Research Directors Office Office of the Scientific Director Sheldon S. Miller, Ph.D., ... David M. Schneeweis, Ph.D., Deputy Scientific Director Office of the Clinical Director Brian P. Brooks, M. ...

  1. Disability: recommendations for eye programmes

    Directory of Open Access Journals (Sweden)

    2013-05-01

    Full Text Available In 2012, CBM’s Medical Eye Care Advisory Working Group met in Hyderabad, India to discuss the inclusion of people with disabilities in eye care.As a result of these discussions, recommendations were made.

  2. Unilateral Amblyopia Affects Two Eyes: Fellow Eye Deficits in Amblyopia.

    Science.gov (United States)

    Meier, Kimberly; Giaschi, Deborah

    2017-03-01

    Unilateral amblyopia is a visual disorder that arises after selective disruption of visual input to one eye during critical periods of development. In the clinic, amblyopia is understood as poor visual acuity in an eye that was deprived of pattern vision early in life. By its nature, however, amblyopia has an adverse effect on the development of a binocular visual system and the interactions between signals from two eyes. Visual functions aside from visual acuity are impacted, and many studies have indicated compromised sensitivity in the fellow eye even though it demonstrates normal visual acuity. While these fellow eye deficits have been noted, no overarching theory has been proposed to describe why and under what conditions the fellow eye is impacted by amblyopia. Here, we consider four explanations that may account for decreased fellow eye sensitivity: the fellow eye is adversely impacted by treatment for amblyopia; the maturation of the fellow eye is delayed by amblyopia; fellow eye sensitivity is impacted for visual functions that rely on binocular cortex; and fellow eye deficits reflect an adaptive mechanism that works to equalize the sensitivity of the two eyes. To evaluate these ideas, we describe five visual functions that are commonly reported to be deficient in the amblyopic eye (hyperacuity, contrast sensitivity, spatial integration, global motion, and motion-defined form), and unify the current evidence for fellow eye deficits. Further research targeted at exploring fellow eye deficits in amblyopia will provide us with a broader understanding of normal visual development and how amblyopia impacts the developing visual system.

  3. Pink Eye: What To Do

    Centers for Disease Control (CDC) Podcasts

    2010-10-12

    In this podcast, CDC's Adam Cohen, MD, a pediatrician and parent, discusses conjunctivitis (pink eye), a common eye condition in children and adults. He reviews pink eye causes and treatment, suggestions on when to call or visit a doctor, and practical tips to prevent pink eye from spreading.  Created: 10/12/2010 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 10/13/2010.

  4. A nonlinear training set superposition filter derived by neural network training methods for implementation in a shift-invariant optical correlator

    Science.gov (United States)

    Kypraios, Ioannis; Young, Rupert C. D.; Birch, Philip M.; Chatwin, Christopher R.

    2003-08-01

    The various types of synthetic discriminant function (sdf) filter result in a weighted linear superposition of the training set images. Neural network training procedures result in a non-linear superposition of the training set images or, effectively, a feature extraction process, which leads to better interpolation properties than achievable with the sdf filter. However, generally, shift invariance is lost since a data dependant non-linear weighting function is incorporated in the input data window. As a compromise, we train a non-linear superposition filter via neural network methods with the constraint of a linear input to allow for shift invariance. The filter can then be used in a frequency domain based optical correlator. Simulation results are presented that demonstrate the improved training set interpolation achieved by the non-linear filter as compared to a linear superposition filter.

  5. Eye-based head gestures

    DEFF Research Database (Denmark)

    Mardanbegi, Diako; Witzner Hansen, Dan; Pederson, Thomas

    2012-01-01

    A novel method for video-based head gesture recognition using eye information by an eye tracker has been proposed. The method uses a combination of gaze and eye movement to infer head gestures. Compared to other gesture-based methods a major advantage of the method is that the user keeps the gaze...

  6. Coherent Superposition States of Atoms and Molecules in a Bose-Einstein Condensate with Exactly Balanced Photo-Associations and Photo-Dissociations

    Institute of Scientific and Technical Information of China (English)

    杨晓雪; 吴颖

    2003-01-01

    We show that there exist a series of coherent superposition states of atoms and molecules in a dilute Bose-Einstein condensate with exactly balanced photo-associations and photo-dissociations, and their analytical expressions are explicitly given. They also correspond to the coherent superposition states of two kinds of photons in optical second harmonic generation processes, which shows exactly balanced down- and up-conversions.

  7. Tips for Buying Sports Eye Protectors

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  8. Checklist for Your Eye Doctor Appointment

    Science.gov (United States)

    ... Financial Assistance Information Vision Screening and Eye Exams Zika Virus and Vision Eye Problems Eye Problems Amblyopia ( ... Eye Health Report Reports and External Resources The Cost of Vision Problems The Future of Vision Vision ...

  9. Eye Symptom Questionnaire to Evaluate Anterior Eye Health.

    Science.gov (United States)

    Woodward, Maria A; Valikodath, Nita G; Newman-Casey, Paula Anne; Niziol, Leslie M; Musch, David C; Lee, Paul P

    2017-06-14

    Ophthalmologists assess eye complaints with a careful history and eye examination; however, other types of physicians have limited tools to evaluate anterior segment (AS) eye diseases. We identified the eye symptom questions that providers should ask to help determine the presence and urgency of AS eye diseases. Persons with and without AS disease completed a self-report eye symptom questionnaire (ESQ) based on the National Institutes of Health Toolbox symptom items in an academic center's corneal and comprehensive eye clinics. Gold standard ophthalmic examination determined the presence and urgency of AS disease. The association between reported symptom severity and the probability of AS disease, or urgent AS disease, was evaluated using logistic regression models, and sensitivity and specificity of the ESQ were also calculated. A total of 324 eyes of 162 subjects were included in the study. Of these, AS disease was present in 255 eyes (79%); of which, 111 eyes showed urgent disease. Increasing symptom severity for eye pain (odds ratio [OR]=2.58; P<0.001), glare (OR=2.61; P=0.001), and blurry vision (OR=1.98; P<0.001) were associated with increased odds of AS disease. Increasing symptom severity for eye pain (OR=2.02; P<0.001), eye redness (OR=1.69; P=0.02), and blurry vision (OR=1.41, P=0.01) were associated with increased odds of urgent AS disease. For the primary analysis with mild symptoms considered relevant, the sensitivity of the ESQ to detect AS disease was 83% and to detect urgent AS disease was 92%. Symptoms of eye pain, glare, redness, and blurry vision indicate the presence and urgency of AS disease.

  10. Prevention and treatment of transient dry eye following excimer laser surgery

    Directory of Open Access Journals (Sweden)

    V. V. Pogorelovа

    2015-01-01

    Full Text Available To compare dry eye symptoms after LASIK with mechanical keratome-created flaps and femtosecond laser keratome-created flaps as well as to analyze the efficacy of Systane® Ultra Monodose used to prevent and to treat transient dry eye after excimer laser surgery. Methods: 98 patients (194 eyes with myopia and compound myopic astigmatism who underwent excimer laser surgery were included in the study. In group 1 patients with pre-op dry eye, femtosecond laser-assisted LASIK was performed, Systane® Ultra Monodose was prescribed postoperatively. In group 2 patients with pre-op dry eye, LASIK was performed using mechanical microkeratome, Systane® Ultra Monodose was prescribed postoperatively. In group 3 patients without pre-op dry eye, LASIK was performed using mechanical microkeratome, standard anti-inflammatory therapy without any lubricant eye drops was prescribed. Patients were followed up for 60 days. Results: It was demonstrated that excimer laser surgery provokes transient dry eye in all patients, therefore, artificial tears are required for 2 months and more after the surgery. Post-operative lubricant eye drops use improves tear film stability, tear production, tear osmolarity, and objective signs of dry eye. Femtosecond laser decreases clinical and functional symptoms of transient dry eye as compared with mechanical microkeratome and provides more rapid visual recovery. Conclusion: Systane® Ultra Monodose has both high efficiency and good tolerability. It can be recommended for the prevention and treatment of dry eye following excimer laser surgery.

  11. Prevention and treatment of transient dry eye following excimer laser surgery

    Directory of Open Access Journals (Sweden)

    V. V. Pogorelovа

    2014-01-01

    Full Text Available To compare dry eye symptoms after LASIK with mechanical keratome-created flaps and femtosecond laser keratome-created flaps as well as to analyze the efficacy of Systane® Ultra Monodose used to prevent and to treat transient dry eye after excimer laser surgery. Methods: 98 patients (194 eyes with myopia and compound myopic astigmatism who underwent excimer laser surgery were included in the study. In group 1 patients with pre-op dry eye, femtosecond laser-assisted LASIK was performed, Systane® Ultra Monodose was prescribed postoperatively. In group 2 patients with pre-op dry eye, LASIK was performed using mechanical microkeratome, Systane® Ultra Monodose was prescribed postoperatively. In group 3 patients without pre-op dry eye, LASIK was performed using mechanical microkeratome, standard anti-inflammatory therapy without any lubricant eye drops was prescribed. Patients were followed up for 60 days. Results: It was demonstrated that excimer laser surgery provokes transient dry eye in all patients, therefore, artificial tears are required for 2 months and more after the surgery. Post-operative lubricant eye drops use improves tear film stability, tear production, tear osmolarity, and objective signs of dry eye. Femtosecond laser decreases clinical and functional symptoms of transient dry eye as compared with mechanical microkeratome and provides more rapid visual recovery. Conclusion: Systane® Ultra Monodose has both high efficiency and good tolerability. It can be recommended for the prevention and treatment of dry eye following excimer laser surgery.

  12. "Eye Science" in 2011

    Institute of Scientific and Technical Information of China (English)

    Jian Ge

    2011-01-01

    @@ 2011 is an opportune time for Yanke Xuebao (Eye Science) to launch its bilingual edition as a platform for cooperation between Chinese and international vision researchers.The yearly research output of Chinese investigators in all fields of science, but particularly biomedicine, has been growing recently by leaps and bounds.As an example, the American Journal of Ophthalmology (AJO), one of the most prestigious clinical journals in our field,received more submissions from East Asian authors (Japan, China and Korea alone)than they did from the United States in 2010.Chinese investigators ranked third on the list, climbing rapidly, only after the US and Japan.Top vision research centers in China, such as Zhongshan Ophthalmic Center, where Eye Science is published, now rank alongside Moorfields and Johns Hopkins as among the most prolific institutions in the world, measured by articles appearing annually in peer-reviewed SCI journals.

  13. Evolution of eye morphology and rhodopsin expression in the Drosophila melanogaster species subgroup.

    Directory of Open Access Journals (Sweden)

    Nico Posnien

    Full Text Available A striking diversity of compound eye size and shape has evolved among insects. The number of ommatidia and their size are major determinants of the visual sensitivity and acuity of the compound eye. Each ommatidium is composed of eight photoreceptor cells that facilitate the discrimination of different colours via the expression of various light sensitive Rhodopsin proteins. It follows that variation in eye size, shape, and opsin composition is likely to directly influence vision. We analyzed variation in these three traits in D. melanogaster, D. simulans and D. mauritiana. We show that D. mauritiana generally has larger eyes than its sibling species, which is due to a combination of larger ommatidia and more ommatidia. In addition, intra- and inter-specific differences in eye size among D. simulans and D. melanogaster strains are mainly caused by variation in ommatidia number. By applying a geometric morphometrics approach to assess whether the formation of larger eyes influences other parts of the head capsule, we found that an increase in eye size is associated with a reduction in the adjacent face cuticle. Our shape analysis also demonstrates that D. mauritiana eyes are specifically enlarged in the dorsal region. Intriguingly, this dorsal enlargement is associated with enhanced expression of rhodopsin 3 in D. mauritiana. In summary, our data suggests that the morphology and functional properties of the compound eyes vary considerably within and among these closely related Drosophila species and may be part of coordinated morphological changes affecting the head capsule.

  14. Light on the moth-eye corneal nipple array of butterflies

    NARCIS (Netherlands)

    Stavenga, DG; Foletti, S; Palasantzas, G; Arikawa, K

    2006-01-01

    The outer surface of the facet lenses in the compound eyes of moths consists of an array of excessive cuticular protuberances, termed corneal nipples. We have investigated the moth-eye corneal nipple array of the facet lenses of 19 diurnal butterfly species by scanning electron microscopy,

  15. Dry Eye Syndrome

    Directory of Open Access Journals (Sweden)

    Mohammad-Ali Javadi

    2011-01-01

    Full Text Available Our understanding of keratoconjunctivitis sicca (KCS, also known as dry eye syndrome, has been changed over recent years. Until lately, the condition was thought to be merely due to aqueous tear insufficiency. Today, it is understood that KCS is a multifactorial disorder due to inflammation of the ocular surface and lacrimal gland, neurotrophic deficiency and meibomian gland dysfunction. This change in paradigm has led to the development of new and more effective medications.

  16. Eye development and photoreceptor differentiation in the cephalopod Doryteuthis pealeii.

    Science.gov (United States)

    Koenig, Kristen M; Sun, Peter; Meyer, Eli; Gross, Jeffrey M

    2016-09-01

    Photoreception is a ubiquitous sensory ability found across the Metazoa, and photoreceptive organs are intricate and diverse in their structure. Although the morphology of the compound eye in Drosophila and the single-chambered eye in vertebrates have elaborated independently, the amount of conservation within the 'eye' gene regulatory network remains controversial, with few taxa studied. To better understand the evolution of photoreceptive organs, we established the cephalopod Doryteuthis pealeii as a lophotrochozoan model for eye development. Utilizing histological, transcriptomic and molecular assays, we characterize eye formation in Doryteuthis pealeii Through lineage tracing and gene expression analyses, we demonstrate that cells expressing Pax and Six genes incorporate into the lens, cornea and iris, and the eye placode is the sole source of retinal tissue. Functional assays demonstrate that Notch signaling is required for photoreceptor cell differentiation and retinal organization. This comparative approach places the canon of eye research in traditional models into perspective, highlighting complexity as a result of both conserved and convergent mechanisms.

  17. Comprehensive eye evaluation algorithm

    Science.gov (United States)

    Agurto, C.; Nemeth, S.; Zamora, G.; Vahtel, M.; Soliz, P.; Barriga, S.

    2016-03-01

    In recent years, several research groups have developed automatic algorithms to detect diabetic retinopathy (DR) in individuals with diabetes (DM), using digital retinal images. Studies have indicated that diabetics have 1.5 times the annual risk of developing primary open angle glaucoma (POAG) as do people without DM. Moreover, DM patients have 1.8 times the risk for age-related macular degeneration (AMD). Although numerous investigators are developing automatic DR detection algorithms, there have been few successful efforts to create an automatic algorithm that can detect other ocular diseases, such as POAG and AMD. Consequently, our aim in the current study was to develop a comprehensive eye evaluation algorithm that not only detects DR in retinal images, but also automatically identifies glaucoma suspects and AMD by integrating other personal medical information with the retinal features. The proposed system is fully automatic and provides the likelihood of each of the three eye disease. The system was evaluated in two datasets of 104 and 88 diabetic cases. For each eye, we used two non-mydriatic digital color fundus photographs (macula and optic disc centered) and, when available, information about age, duration of diabetes, cataracts, hypertension, gender, and laboratory data. Our results show that the combination of multimodal features can increase the AUC by up to 5%, 7%, and 8% in the detection of AMD, DR, and glaucoma respectively. Marked improvement was achieved when laboratory results were combined with retinal image features.

  18. Lagophthalmos in enophthalmic eyes.

    Science.gov (United States)

    Yip, C-C; Gonzalez-Candial, M; Jain, A; Goldberg, R A; McCann, J D

    2005-06-01

    To report a case series of enophthalmic patients with lagophthalmos. A retrospective review of the electronic medical records at a tertiary health care centre of all patients with the diagnoses of "enophthalmos" and "lagophthalmos". Patients who had a history of diseases (such as Graves' orbitopathy), trauma or surgery of the orbit and eyelid were excluded. Enophthalmos was defined as exophthalmometric reading of 14 mm or less in both eyes. Seven patients (14 eyes) with bilateral enophthalmos were found to have concomitant lagophthalmos. All patients had deep superior sulci bilaterally. The upper eyelids were seen to be severely retro-placed behind the superior orbital rim. The extraocular motilities were full with no focal neurological deficit. The orbicularis oculi function was normal with no facial paralysis. The orbits were soft on retropulsion and no facial asymmetry was noted. The mean exophthalmolmetry reading measured 12.6 (SD 1.1) mm. The lagophthalmos varied from 1-5 mm. One patient (one eye) with 3 mm lagophthalmos developed a corneal ulcer and was treated with topical antibiotics and gold weight placement in the upper eyelid. Enophthalmic patients with deep superior sulci and retro-placed upper eyelids may present with lagophthalmos and exposure keratopathy.

  19. Abnormal Spontaneous Eye Movements as Initial Presentation of Organophosphate Poisoning

    Science.gov (United States)

    De Lima Teixeira, Igor; Bazan, Silméia Garcia Zanati; Schelp, Arthur Oscar; Luvizutto, Gustavo José; De Lima, Fabrício Diniz; Bazan, Rodrigo

    2017-01-01

    Background Atypical ocular bobbing may result from an intentional poisoning from an organophosphate compound. Phenomenology Shown The patient exhibited conjugated, slow, arrhythmic, unpredictable eye movements in all directions, diagnosed as atypical ocular bobbing. Educational Value This is a rare, well‐documented, clinically relevant case for medical students for correct diagnosis and appropriate treatment of organophosphate intoxication. PMID:28243486

  20. Microwave sintering versus conventional sintering of NiCuZn ferrites. Part II: Microstructure and DC-bias superposition characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Chenxin, E-mail: cxouyang@foxmail.com [Department of Materials Science and Engineering, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, Guangdong 518055 (China); Research Center, Shenzhen Zhenhua Fu Electronics Co., Ltd., Shenzhen, Guangdong 518109 (China); Xiao, Shumin [Department of Materials Science and Engineering, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, Guangdong 518055 (China); Zhu, Jianhua [Research Center, Shenzhen Zhenhua Fu Electronics Co., Ltd., Shenzhen, Guangdong 518109 (China); College of Optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong 518060 (China); Shi, Wei [Research Center, Shenzhen Zhenhua Fu Electronics Co., Ltd., Shenzhen, Guangdong 518109 (China)

    2016-06-01

    NiCuZn ferrites with the composition of (Ni{sub 0.48}Cu{sub 0.10}Zn{sub 0.42}O){sub 1.04}(Fe{sub 2}O{sub 3}){sub 0.96} were consolidated by microwave sintering (MS) and conventional sintering (CS), respectively. The influences of external microwave field and additives (1 wt% BSZ glass or 1 wt% Bi{sub 2}O{sub 3}) on the microstructure and DC-bias superposition characteristics of NiCuZn ferrites were investigated. Experimental results demonstrated that the final grain size was much larger with higher density since applying microwave field. In addition, for undoped ferrites, coarse grains structure obtained from microwave sintering is harmful to the DC-bias superposition characteristics. However, since adding BSZ glass or Bi{sub 2}O{sub 3}, the discrepancy on the final grain size obtained from MS and CS methods is not obvious. NiCuZn ferrites with the addition of BSZ glass or Bi{sub 2}O{sub 3} exhibited a stronger ability to inhibit the drop of permeability under the DC-bias magnetic field. Possible mechanisms behind are discussed in this article. - Highlights: • Magnetization process of NiCuZn ferrite under bias current field is studied. • Coarse grains size from microwave sintering is harmful to endure bias current attack. • BSZ glass and Bi{sub 2}O{sub 3} could enhance the density and DC-bias superposition property.

  1. An application of superpositions of two-state Markovian sources to the modelling of self-similar behaviour

    DEFF Research Database (Denmark)

    Andersen, Allan T.; Nielsen, Bo Friis

    1997-01-01

    We present a modelling framework and a fitting method for modelling second order self-similar behaviour with the Markovian arrival process (MAP). The fitting method is based on fitting to the autocorrelation function of counts a second order self-similar process. It is shown that with this fitting...... algorithm it is possible closely to match the autocorrelation function of counts for a second order self-similar process over 3-5 time-scales with 8-16 state MAPs with a very simple structure, i.e. a superposition of 3 and 4 interrupted Poisson processes (IPP) respectively and a Poisson process. The fitting...

  2. Universal quantum computation with electron spins in quantum dots based on superpositions of spacetime paths and Coulomb blockade

    CERN Document Server

    Lin, C C Y; Wu, Y Z; Zhang, W M; Lin, Cyrus C.Y.; Soo, Chopin; Wu, Yin-Zhong; Zhang, Wei-Min

    2004-01-01

    Using electrostatic gates to control the electron positions, we present a new controlled-NOT gate based on quantum dots. The qubit states are chosen to be the spin states of an excess conductor electron in the quantum dot; and the main ingredients of our scheme are the superpositions of space-time paths of electrons and the effect of Coulomb blockade. All operations are performed only on individual quantum dots and are based on fundamental interactions. Without resorting to spin-spin terms or other assumed interactions, the scheme can be realized with a dedicated circuit and a necessary number of quantum dots. Gate fidelity of the quantum computation is also presented.

  3. Application of coupled mode theory and coherent superposition theory to phase-shift measurements on optical microresonators

    Science.gov (United States)

    Barnes, Jack A.; Loock, Hans-Peter

    2016-10-01

    Several mathematical models exist in the literature to describe the properties of optical resonators. Here, coupled mode theory and coherent superposition theory are compared and their consistency is demonstrated as they are applied to phase-shift cavity ring-down measurements in optical (micro-)cavities. In the particular case of a whispering gallery mode in a microsphere cavity these models are applied to transmission measurements and backscattering measurements through the fiber taper that couples light into the microresonator. It is shown that both models produce identical relations when applied to these traveling wave cavities.

  4. Simultaneous Determination of Three Active Ingredients in Compound Allantoin VitaminB6-E and Aminoethylsulfonic Acid Eye Drops by HPLC-DAD%HPLC-DAD同时测定复方尿维氨滴眼液中3种活性成分的含量

    Institute of Scientific and Technical Information of China (English)

    金鹏飞; 吴学军; 邹定; 马捷; 姜文清; 郭郁

    2009-01-01

    OBJECTIVE To establish a high performance liquid chromatography-diode array detection (HPLC-DAD) method for the simultaneous determination of chondroitin sulfate sodium, allantoin and vitamin B_6 in Compound Allantoin VitaminB_6-E and Aminoethylsulfonic Acid Eye Drops. METHODS An Alltima C_(18) column (4.6 mm×250 mm, 5 μm particle size) was used for the separation at room temperature, with 25 mmol-L~(-1) ammonium dihydrogen phosphate (containing 0.01% heptanesulfonic acid sodium salt)-acetonitrile (95:5) as the mobile phase at the flow rate of 0.5 mL·min~(-1). The detection wavelengthes for chondroitin sulfate sodium, allantoin and vitamin B_6 were 195, 215 and 291 ran, respectively. RESULTS The method showed good linearity for chondroitin sulfate sodium, allantoin and vitamin B_6, with all correlation coefficients (r) greater than 0.999 6. The specificity study showed satisfactory resolutions between chondroitin sulfate sodium, allantoin, vitamin B_6 other ingredients and forced degradation products. The precisions and stability were satisfactory with all relative standard deviations (RSD) of peak areas lower than 2.0%, and the spiked recovery of three ingredients ranged from 99.01% to 101.92%. CONCLUSION This method is an accurate, fast and simple method for the simultaneous determination of chondroitin sulfate sodium, allantoin and vitamin B6 in Compound Allantoin VitaminB_6-E and Aminoethylsulfonic Acid Eye Drops.%目的 应用高效液相色谱-二极管阵列检测器(HPLC-DAD),建立复方尿维氨滴眼液中硫酸软骨素钠,尿囊素和维生素B6含量的同时测定方法.方法 采用Alltima C_(18)色谱柱(4.6 mm×250 mm,5μm),以25 mmol·L~(-1)磷酸二氢铵(含0.01%辛烷磺酸钠)-乙睛(95:5)为流动相,流速0.5 mL·min~(-1),室温测定,硫酸软骨素钠,尿囊素和维生素B6的检测波长分别为195,215和291mm.结果 硫酸软骨素钠,尿囊素和维生素B6的线性关系良好,线性相关系数(r)都大于0.999 6;专属性强,3

  5. Polybenzimidazole compounds

    Science.gov (United States)

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  6. Reconstructing the ancestral butterfly eye: focus on the opsins.

    Science.gov (United States)

    Briscoe, Adriana D

    2008-06-01

    The eyes of butterflies are remarkable, because they are nearly as diverse as the colors of wings. Much of eye diversity can be traced to alterations in the number, spectral properties and spatial distribution of the visual pigments. Visual pigments are light-sensitive molecules composed of an opsin protein and a chromophore. Most butterflies have eyes that contain visual pigments with a wavelength of peak absorbance, lambda(max), in the ultraviolet (UV, 300-400 nm), blue (B, 400-500 nm) and long wavelength (LW, 500-600 nm) part of the visible light spectrum, respectively, encoded by distinct UV, B and LW opsin genes. In the compound eye of butterflies, each individual ommatidium is composed of nine photoreceptor cells (R1-9) that generally express only one opsin mRNA per cell, although in some butterfly eyes there are ommatidial subtypes in which two opsins are co-expressed in the same photoreceptor cell. Based on a phylogenetic analysis of opsin cDNAs from the five butterfly families, Papilionidae, Pieridae, Nymphalidae, Lycaenidae and Riodinidae, and comparative analysis of opsin gene expression patterns from four of the five families, I propose a model for the patterning of the ancestral butterfly eye that is most closely aligned with the nymphalid eye. The R1 and R2 cells of the main retina expressed UV-UV-, UV-B- or B-B-absorbing visual pigments while the R3-9 cells expressed a LW-absorbing visual pigment. Visual systems of existing butterflies then underwent an adaptive expansion based on lineage-specific B and LW opsin gene multiplications and on alterations in the spatial expression of opsins within the eye. Understanding the molecular sophistication of butterfly eye complexity is a challenge that, if met, has broad biological implications.

  7. Simultaneous nonlinear encryption of grayscale and color images based on phase-truncated fractional Fourier transform and optical superposition principle.

    Science.gov (United States)

    Wang, Xiaogang; Zhao, Daomu

    2013-09-01

    A nonlinear color and grayscale images cryptosystem based on phase-truncated fractional Fourier transform and optical superposition principle is proposed. In order to realize simultaneous encryption of color and grayscale images, each grayscale image is first converted into two phase masks by using an optical coherent superposition, one of which is treated as a part of input information that will be fractional Fourier transformed while the other in the form of a chaotic random phase mask (CRPM) is used as a decryption key. For the purpose of optical performance, all the processes are performed through three channels, i.e., red, green, and blue. Different from most asymmetric encryption methods, the decryption process is designed to be linear for the sake of effective decryption. The encryption level of a double random phase encryption based on phase-truncated Fourier transform is enhanced by extending it into fractional Fourier domain and the load of the keys management and transmission is lightened by using CRPMs. The security of the proposed cryptosystem is discussed and computer simulation results are presented to verify the validity of the proposed method.

  8. Through Einstein's Eyes

    CERN Document Server

    Searle, A C; Altin, P A; Bennet, F H; Hush, M R; Searle, Antony C.; Savage, Craig M.; Altin, Paul A.; Bennet, Francis H.; Hush, Michael R.

    2005-01-01

    We have developed a relativistically-accurate computer graphics code and have used it to produce photo-realistic images and videos of scenes where special relativistic effects dominate, either in astrophysical contexts or in imaginary worlds where the speed of light is only a few metres per second. The videos have been integrated into our under-graduate teaching programme for several years. Recently we took the next step, encouraging undergraduate students to use the code to explore relativity, develop their own videos, and eventually package them together into Through Einstein's Eyes, a multimedia CD.

  9. Eye trauma in boxing.

    Science.gov (United States)

    Corrales, Gustavo; Curreri, Anthony

    2009-10-01

    In boxing, along with a few other sports, trauma is inherent to the nature of the sport; therefore it is considered a high-risk sport for ocular injuries. The long-term morbidity of ocular injuries suffered by boxers is difficult to estimate due to the lack of structured long-term follow-up of these athletes. Complications of blunt ocular trauma may develop years after the athlete has retired from the ring and is no longer considered to be at risk for boxing-related injuries. This article describes the wide range of eye injuries a boxer can sustain, and their immediate and long-term clinical management.

  10. A Seeing-eye Dog

    Institute of Scientific and Technical Information of China (English)

    范图雨

    2000-01-01

    A seeing-eye dog is a special(特殊的) dog. It helps blind people walk along the streets and do many other things. We call these dogs ""seeing-eye"" dogs because the dogs are the ""eyes"" of the blind man and they help him to ""see"". These dogs go to special schools for several years to learn to help blind people.

  11. Reading between eye saccades.

    Directory of Open Access Journals (Sweden)

    Caroline Blais

    Full Text Available BACKGROUND: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question. METHODOLOGY/PRINCIPAL FINDINGS: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words. CONCLUSIONS/SIGNIFICANCE: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a word-length effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an important role in further examining the nature of reading between eye saccades.

  12. Eye in pregnancy

    Directory of Open Access Journals (Sweden)

    Achyut N. Pandey

    2014-02-01

    Full Text Available Hormonal, metabolic, hemodynamic, vascular and immunological changes that occur during pregnancy can affect the function of the eye. These changes are commonly transient, but in some cases they may be permanent and have consequences even after childbirth. The ocular effects of pregnancy may be physiological or pathological and can be associated with the development of new ocular pathology or may be modifications of pre-existing conditions. The most common physiological changes are alterations of corneal sensitivity and thickness, decreased tolerance to contact lenses, decreased intraocular pressure, hemeralopia and refractive errors. Possible posterior segment changes include worsening of diabetic retinopathy, central serous chorioretinopathy, increased risk of peripheral vitreochorioretinal dystrophies and retinal detachment. Thus, it should be kept in mind that the presence of any ocular symptoms in a pregnant woman requires ophthalmologic examination and further management. Knowledge of these ocular changes can help to differentiate the physiological changes from ocular manifestation of systemic disease and diseases pertaining to the eye in a pregnant woman. This article explains the effects of ocular changes in pregnancy. [Int J Res Med Sci 2014; 2(1.000: 16-20

  13. Adsorption of Organic Compounds to Building Products

    DEFF Research Database (Denmark)

    Kjær, Ulla Dorte

    The presence of VOCs (Volatile Organic Compounds) in the indoor air may be a contributory cause of complaints about irritation of mucous membranes in eyes, nose and throat, difficulty in breathing, frequent airway inflammation, skin irritation, fatigue, concentration difficulty, dizziness and hea...

  14. Multipurpose Compound

    Science.gov (United States)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  15. Amblyopia: What Is the Cause of Lazy Eye?

    Science.gov (United States)

    ... Stories Español Eye Health / Eye Health A-Z Amblyopia Sections Amblyopia: What Is Lazy Eye? Amblyopia: What ... Amblyopia: Lazy Eye Diagnosis Amblyopia: Lazy Eye Treatment Amblyopia: What Is the Cause of Lazy Eye? Leer ...

  16. Choosing Wisely When It Comes to Eye Care: Antibiotics for Eye Injections

    Science.gov (United States)

    ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an ... healthy lifestyle choices can help you protect your vision by reducing your risk for eye diseases , eye infections and eye injuries . Partnering with your ...

  17. Choosing Wisely When It Comes to Eye Care: Antibiotics for Pink Eye

    Science.gov (United States)

    ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an ... healthy lifestyle choices can help you protect your vision by reducing your risk for eye diseases , eye infections and eye injuries . Partnering with your ...

  18. Choosing Wisely When It Comes to Eye Care: Punctal Plugs for Dry Eye

    Science.gov (United States)

    ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an ... healthy lifestyle choices can help you protect your vision by reducing your risk for eye diseases, eye infections and eye injuries . Partnering with your ...

  19. Danish Rural Eye Study

    DEFF Research Database (Denmark)

    Høeg, Tracy B; Moldow, Birgitte; Ellervik, Christina

    2015-01-01

    PURPOSE: To determine the prevalence of amblyopia in Denmark before and after the initiation of the Danish national preschool vision screening programme. METHODS: In a population-based cross-sectional study, 3826 participants of the Danish General Suburban Population Study (GESUS) aged 20 years...... 45-degree retinal fundus photographs of each eye. A complete ophthalmologic examination was performed when indicated. RESULTS: The prevalence of monocular visual impairment (MVI) was 4.26% (95% CI, 3.66-4.95, n = 163). Amblyopia was the most common cause, accounting for 33%. The prevalence...... of amblyopia was 1.44% (95% CI, 1.01-1.81, n = 55), being higher among non-preschool vision screened persons compared to those who were offered (estimated 95% attendance) preschool vision screening (1.78%, n = 41, 95% CI 1.24-2.33 versus 0.44%, n = 2, 95% CI, 0.12-1.60, p = 0.024). The leading cause...

  20. The Colossal Cosmic Eye

    Science.gov (United States)

    2005-09-01

    Eighty-five million years ago on small planet Earth, dinosaurs ruled, ignorant of their soon-to-come demise in the great Jurassic extinction, while mammals were still small and shy creatures. The southern Andes of Bolivia, Chile, and Argentina were not yet formed and South America was still an island continent. Eighty-five million years ago, our Sun and its solar system was 60,000 light years away from where it now stands [1]. Eighty-five million years ago, in another corner of the Universe, light left the beautiful spiral galaxy NGC 1350, for a journey across the universe. Part of this light was recorded at the beginning of the year 2000 AD by ESO's Very Large Telescope, located on the 2,600m high Cerro Paranal in the Chilean Andes on planet Earth. Astronomers classify NGC 1350 as an Sa(r) type galaxy, meaning it is a spiral with large central regions. In fact, NGC 1350 lies at the border between the broken-ring spiral type and a grand design spiral with two major outer arms. It is about 130,000 light-years across and, hence, is slightly larger than our Milky Way. The rather faint and graceful outer arms originate at the inner main ring and can be traced for almost half a circle when they each meet the opposite arm, giving the impression of completing a second outer ring, the "eye". The arms are given a blue tint as a result of the presence of very young and massive stars. The amount of dust, seen as small fragmented dust spirals in the central part of the galaxy and producing a fine tapestry that bear resemblance with blood vessels in the eye, is also a signature of the formation of stars.