Sample records for incident optical vergence

  1. Grazing Incidence Optics Technology (United States)

    Ramsey, Brian; Smith, W. Scott; Gubarev, Mikhail; McCracken, Jeff


    This project is to demonstrate the capability to directly fabricate lightweight, high-resolution, grazing-incidence x-ray optics using a commercially available robotic polishing machine. Typical x-ray optics production at NASA Marshall Space Flight Center (MSFC) uses a replication process in which metal mirrors are electroformed on to figured and polished mandrels from which they are later removed. The attraction of this process is that multiple copies can be made from a single master. The drawback is that the replication process limits the angular resolution that can be attained. By directly fabricating each shell, errors inherent in the replication process are removed. The principal challenge now becomes how to support the mirror shell during all aspects of fabrication, including the necessary metrology to converge on the required mirror performance specifications. This program makes use of a Zeeko seven-axis computer-controlled polishing machine (see fig. 1) and supporting fabrication, metrology, and test equipment at MSFC. The overall development plan calls for proof-of-concept demonstration with relatively thick mirror shells (5-6 mm, fig. 2) which are straightforward to support and then a transition to much thinner shells (2-3 mm), which are an order of magnitude thinner than those used for Chandra. Both glass and metal substrates are being investigated. Currently, a thick glass shell is being figured. This has enabled experience to be gained with programming and operating the polishing machine without worrying about shell distortions or breakage. It has also allowed time for more complex support mechanisms for figuring/ polishing and metrology to be designed for the more challenging thinner shells. These are now in fabrication. Figure 1: Zeeko polishing machine.

  2. Grazing Incidence Neutron Optics (United States)

    Gubarev, Mikhail V. (Inventor); Ramsey, Brian D. (Inventor); Engelhaupt, Darell E. (Inventor)


    Neutron optics based on the two-reflection geometries are capable of controlling beams of long wavelength neutrons with low angular divergence. The preferred mirror fabrication technique is a replication process with electroform nickel replication process being preferable. In the preliminary demonstration test an electroform nickel optics gave the neutron current density gain at the focal spot of the mirror at least 8 for neutron wavelengths in the range from 6 to 20.ANG.. The replication techniques can be also be used to fabricate neutron beam controlling guides.

  3. Vergence Eye Movements in Patients with Schizophrenia (United States)

    Bolding, MS; Lahti, AC; White, D; Moore, C; Gurler, D; Gawne, TJ; Gamlin, PD


    Previous studies have shown that smooth pursuit eye movements are impaired in patients with schizophrenia. However, under normal viewing conditions, targets move not only in the frontoparallel plane but also in depth, and tracking them requires both smooth pursuit and vergence eye movements. Although previous studies in humans and non-human primates suggest that these two eye movement subsystems are relatively independent of one another, to our knowledge, there have been no prior studies of vergence tracking behavior in patients with schizophrenia. Therefore, we have investigated these eye movements in patients with schizophrenia and in healthy controls. We found that patients with schizophrenia exhibited substantially lower gains compared to healthy controls during vergence tracking at all tested speeds (e.g. 0.25 Hz vergence tracking mean gain of 0.59 vs. 0.86). Further, consistent with previous reports, patients with schizophrenia exhibited significantly lower gains than healthy controls during smooth pursuit at higher target speeds (e.g. 0.5 Hz smooth pursuit mean gain of 0.64 vs. 0.73). In addition, there was a modest (r≈0.5), but significant, correlation between smooth pursuit and vergence tracking performance in patients with schizophrenia. Our observations clearly demonstrate substantial vergence tracking deficits in patients with schizophrenia. In these patients, deficits for smooth pursuit and vergence tracking are partially correlated suggesting overlap in the central control of smooth pursuit and vergence eye movements. PMID:25088242

  4. Rotation of Listing's plane during vergence. (United States)

    Mok, D; Ro, A; Cadera, W; Crawford, J D; Vilis, T


    When visually fixating targets on an isovergence surface, the position of each eye was constrained to a plane. Thus, Listing's law holds during vergence. The planes were, however, rotated temporally with respect to those when viewing distant targets. The effect of this rotation was to produce a torsion which depended on eye elevation; extorsion of the two eyes for downward gaze and intorsion for upward gaze. The saccadic velocity command was relatively unaffected during vergence. Computer simulations suggest that the saccadic tonic command and the vergence command interact multiplicatively in three dimensions.

  5. Vergence findings and horizontal vergence dysfunction among first year university students in Benin City, Nigeria. (United States)

    Ovenseri-Ogbomo, Godwin O; Eguegu, Ovigwe Peter


    The study was designed to determine the prevalence of vergence dysfunctions among first year university students in Nigeria and to document the measures that define the vergence system of the visual system. A cross-sectional study of first year students of the University of Benin, Benin City, Nigeria, who presented for the mandatory eye examination as part of their medical examinations required for clearance was conducted. A battery of tests that defines the vergence system including near and far phoria, positive and negative fusional vergence amplitudes at far and near, near point of convergence (NPC) and AC/A ratio were measured using conventional clinical protocols. The prevalence of vergence dysfunction among 212 first year university students who satisfied the inclusion criteria and gave consent to participate was 12.7%, with convergence insufficiency being the most common vergence dysfunction. Blurred vision, headache and diplopia were the most frequently reported visual symptoms. There is a considerable prevalence of previously undiagnosed vergence dysfunctions in this population of students. The study underscored the need to carry out a thorough binocular vision assessment as part of the battery of tests administered to newly admitted students in this community to forestall any adverse effect the presence of vergence dysfunctions might have on the academic activity of university students. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  6. The current status of grazing incidence optics

    International Nuclear Information System (INIS)

    Aschenbach, B.


    The developments in the area of grazing incidence optics with emphasis on telescopes for use in X-ray astronomy are reviewed. The performance of existing high-resolution telescopes is outlined and compared with those expected from future missions like ROSAT and AXAF. Starting from the basic principles of X-ray reflection and scattering, an attempt is made to highlight the current understanding of X-ray mirror physics using new theoretical ideas as well as experimental laboratory results. (author)

  7. Central crosstalk for somatic tinnitus: abnormal vergence eye movements.

    Directory of Open Access Journals (Sweden)

    Qing Yang

    Full Text Available BACKGROUND: Frequent oulomotricity problems with orthoptic testing were reported in patients with tinnitus. This study examines with objective recordings vergence eye movements in patients with somatic tinnitus patients with ability to modify their subjective tinnitus percept by various movements, such as jaw, neck, eye movements or skin pressure. METHODS: Vergence eye movements were recorded with the Eyelink II video system in 15 (23-63 years control adults and 19 (36-62 years subjects with somatic tinnitus. FINDINGS: 1 Accuracy of divergence but not of convergence was lower in subjects with somatic tinnitus than in control subjects. 2 Vergence duration was longer and peak velocity was lower in subjects with somatic tinnitus than in control subjects. 3 The number of embedded saccades and the amplitude of saccades coinciding with the peak velocity of vergence were higher for tinnitus subjects. Yet, saccades did not increase peak velocity of vergence for tinnitus subjects, but they did so for controls. 4 In contrast, there was no significant difference of vergence latency between these two groups. INTERPRETATION: The results suggest dysfunction of vergence areas involving cortical-brainstem-cerebellar circuits. We hypothesize that central auditory dysfunction related to tinnitus percept could trigger mild cerebellar-brainstem dysfunction or that tinnitus and vergence dysfunction could both be manifestations of mild cortical-brainstem-cerebellar syndrome reflecting abnormal cross-modality interactions between vergence eye movements and auditory signals.

  8. Active Full-Shell Grazing-Incidence Optics (United States)

    Davis, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Gubarev, Mikhail V.


    MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

  9. Optical Co-Incidence Gate | Srinivasulu | African Journal of Science ...

    African Journals Online (AJOL)

    The paper explains Optical co-incidence gate, realized using Unijunction transistors (UJT), Light emitting diodes (LED) and Photo-resistors (LDR), which works on 1.8Vdc instead of 3Vdc. The power dissipation of the designed gate is only 3 mW. This optical gate finds application in the field of Mechatronics, Instrumentation ...

  10. The interactive processes of accommodation and vergence. (United States)

    Semmlow, J L; Bérard, P V; Vercher, J L; Putteman, A; Gauthier, G M


    A near target generates two different, though related stimuli: image disparity and image blur. Fixation of that near target evokes three motor responses: the so-called oculomotor "near triad". It has long been known that both disparity and blur stimuli are each capable of independently generating all three responses, and a recent theory of near triad control (the Dual Interactive Theory) describes how these stimulus components normally work together in the aid of near vision. However, this theory also indicates that when the system becomes unbalanced, as in high AC/A ratios of some accommodative esotropes, the two components will become antagonistic. In this situation, the interaction between the blur and disparity driven components exaggerates the imbalance created in the vergence motor output. Conversely, there is enhanced restoration when the AC/A ratio is effectively reduced surgically.

  11. A normative study of step vergence in elementary schoolchildren. (United States)

    Scheiman, M; Herzberg, H; Frantz, K; Margolies, M


    The purpose of this study was to develop normative data for step vergence testing in children age 6-12. Such data are not currently available for this age group. Base-in and base-out step vergence testing with a prism bar was performed on 386 elementary schoolchildren who had all passed a modified clinical technique (MCT) screening. A new polarized target was developed which enabled us to detect suppression, as well as diplopia or blur. The findings suggest significant differences from normative data previously reported for adults. Because the data for 6-year-olds were different from the rest of the group, we suggest that lower norms be used for this age group. This study provides expected findings for step vergence testing outside the phoropter, which can be used clinically for the assessment of disparity vergence ranges in young children.

  12. Binocular eye orientation during fixations: Listing's law extended to include eye vergence. (United States)

    Van Rijn, L J; Van den Berg, A V


    Any eye position can be reached from a position called the primary position by rotation about a single axis. Listing's law states that for targets at optical infinity all rotation axes form a plane; the so-called Listing plane. Listing's law is not valid for fixation of nearby targets. To document these deviations of Listing's law we studied binocular eye positions during fixations of point targets in the dark. We tested both symmetric (targets in a sagittal plane) and asymmetric vergence conditions. For upward fixation both eyes showed intorsion relative to the position that would have been taken if each eye followed Listing's law. For downward fixation we found extorsion. The in- or extorsion increased approximately linearly with the vergence angle. The direction of the Listing axis and the turn angle about this axis can be described by rotation vectors. Our observations indicate that for fixation of nearby targets the rotation vectors of the two eyes become different and are no longer located in a single plane. However, we find that it is possible to decomose the rotation vector of each eye into the sum of a symmetric and an anti-symmetric part, each with its own properties. (1) The symmetric part is associated with eye version. This component of the rotation vector is identical for both eyes and lies in Listing's plane. In contrast to the classical form of Listing's law, this part of the rotation vector lies in Listing's plane irrespective of the fixation distance. (2) The anti-symmetric part of the rotation vector is related to eye vergence. This component is of equal magnitude but oppositely directed in each eye. The anti-symmetric part lies in the mid-sagittal plane, also irrespective of fixation distance. For fixation of targets at optical infinity the anti-symmetric part equals zero and the eye positions obey the classical form of Listing's law. Thus, the symmetric and anti-symmetric parts of the rotation vectors are restricted to two perpendicular planes

  13. Adjustable Grazing-Incidence X-Ray Optics (United States)

    O'Dell, Stephen L.; Reid, Paul B.


    With its unique subarcsecond imaging performance, NASA's Chandra X-ray Observatory illustrates the importance of fine angular resolution for x-ray astronomy. Indeed, the future of x-ray astronomy relies upon x-ray telescopes with comparable angular resolution but larger aperture areas. Combined with the special requirements of nested grazing-incidence optics, mass, and envelope constraints of space-borne telescopes render such advances technologically and programmatically challenging. The goal of this technology research is to enable the cost-effective fabrication of large-area, lightweight grazing-incidence x-ray optics with subarcsecond resolution. Toward this end, the project is developing active x-ray optics using slumped-glass mirrors with thin-film piezoelectric arrays for correction of intrinsic or mount-induced distortions.

  14. Interaction between Accommodation and Vergence on Distance Perception

    Directory of Open Access Journals (Sweden)

    Tomoyuki Daijogo


    Full Text Available Fisher and Ciuffreda (1988 and Mon-Williams and Tresilian (1999 reported that, without vergence cue, diopter change in accommodation induced change in apparent distance. Meanwhile, there is conflicting evidence about the relative roles of accommodation and vergence in distance perception (Richards & Miller, 1969; von Holst, 1973. In the current study, we investigated interaction between accommodation and vergence on distance perception. The perceived distance from integration of vergence evoked by a fixation target and accommodation by a pair of concave or convex lenses in front of eyes is measured with a mirror stereoscope. The stimulus was a white square with a black cross-shaped fixation on a black background. In dark surroundings, subjects were asked to commit the apparent distance of the target to memory, and then without the lenses, re-create the distance by changing distance of another fixation target. The apparent size of the target through lenses were equivalent to the size without lenses. The results showed that not only vergence but accommodation affect the apparent distance, and they were summed linearly.

  15. Eye vergence responses during a visual memory task. (United States)

    Solé Puig, Maria; Romeo, August; Cañete Crespillo, Jose; Supèr, Hans


    In a previous report it was shown that covertly attending visual stimuli produce small convergence of the eyes, and that visual stimuli can give rise to different modulations of the angle of eye vergence, depending on their power to capture attention. Working memory is highly dependent on attention. Therefore, in this study we assessed vergence responses in a memory task. Participants scanned a set of 8 or 12 images for 10 s, and thereafter were presented with a series of single images. One half were repeat images - that is, they belonged to the initial set - and the other half were novel images. Participants were asked to indicate whether or not the images were included in the initial image set. We observed that eyes converge during scanning the set of images and during the presentation of the single images. The convergence was stronger for remembered images compared with the vergence for nonremembered images. Modulation in pupil size did not correspond to behavioural responses. The correspondence between vergence and coding/retrieval processes of memory strengthen the idea of a role for vergence in attention processing of visual information.

  16. Repeatability and agreement in the measurement of horizontal fusional vergences


    Antona Peñalba, Beatriz; Barrio de Santos, Ana Rosa; Barra Lázaro, Francisco; González Díaz-Obregón, Enrique; Sánchez Pérez, María Isabel


    Purpose: This study was designed to determine the repeatability of fusional vergence rangesmeasured using the rotary prisms in the phoropter and in free space using the prism bar. The level of agreement between the two methods was also investigated.. Methods: In two separate sessions, negative and positive fusional vergence ranges (NFV and PFV, respectively) were measured at distance and near in 61 young adults (mean age 19.74, S.D. 2.5 years) who were unfamiliar with the methods used. Bas...

  17. Functional anatomy of the extraocular muscles during vergence. (United States)

    Demer, Joseph L; Clark, Robert A; Crane, Benjamin T; Tian, Jun-Ru; Narasimhan, Anita; Karim, Shaheen


    Magnetic resonance imaging (MRI) now enables precise visualisation of the mechanical state of the living human orbit, enabling inferences about the effects of mechanical factors on ocular kinematics. We used 3-dimensional (3D) magnetic search coil recordings and MRI to investigate the mechanical state of the orbit during vergence in humans. Horizontal convergence of 23 degrees from a remote to a near target aligned on one eye was geometrically ideal, and was associated with lens thickening and extorsion of the rectus pulley array of the aligned eye with superior oblique muscle relaxation and inferior oblique muscle contraction. There was no rectus muscle co-contraction. Subjective fusion through a 1 degree vertical prism caused a clockwise (CW) torsion in both eyes, as well as variable vertical and horizontal vergences that seldom corresponded to prism amount or direction. MRI under these conditions did not show consistent torsion of the rectus pulley array, but a complex pattern of changes in rectus extraocular muscle (EOM) crossections, consistent with co-contraction. Binocular fusion during vergence is accomplished by complex, 3D eye rotations seldom achieving binocular retinal correspondence. Vergence eye movements are sometimes associated with changes in rectus EOM pulling directions, and may sometimes be associated with co-contraction. Thus, extraretinal information about eye position would appear necessary to interpret binocular correspondence, and to avoid diplopia.

  18. Controlling normal incident optical waves with an integrated resonator. (United States)

    Qiu, Ciyuan; Xu, Qianfan


    We show a diffraction-based coupling scheme that allows a micro-resonator to directly manipulate a free-space optical beam at normal incidence. We demonstrate a high-Q micro-gear resonator with a 1.57-um radius whose vertical transmission and reflection change 40% over a wavelength range of only 0.3 nm. Without the need to be attached to a waveguide, a dense 2D array of such resonators can be integrated on a chip for spatial light modulation and parallel bio-sensing.

  19. Dynamical version--vergence interactions for a binocular implementation of Donders' law. (United States)

    Minken, A W; Van Gisbergen, J A


    Recent investigations of the three-dimensional (3D) binocular eye positions in near vision have shown that a full characterization of vergence requires incorporation of its torsional component. The latter has a proportional relationship with horizontal vergence and elevation, causing the eyes to have intorsion in near upgaze but extorsion in near downgaze. In this study, we focus on the dynamical implementation of the torsional vergence component in both pure vergence and combined direction-depth binocular eye movements. We report on experiments in five subjects whose eye movements were recorded binocularly with the 3D magnetic search-coil technique. In pure vergence movements at a given elevation, torsional vergence increased with almost the same time course as horizontal vergence. In addition, the dynamic relationships among torsional vergence, horizontal vergence and elevation were close to static results in all subjects. In combined direction-depth movements a similar relationship held for the complete movements, but we could not firmly establish a straight-line relationship during the saccadic portion of the movement. Possible factors determining these responses are discussed. We computed the angular velocity profiles of pure vergence movements to see how tilting of the vergence angular velocity axis relative to Listing's plane generates torsional vergence. It is widely held that both saccadic and vergence movements are controlled by dedicated pulse generators specifying velocity signals. Little thought has been given to the question of how these controllers can be coordinated to yield realistic eye movements in 3D. Our finding that this tilt was close to full-angle, suggests a model in which version and vergence velocity signals are combined before the 3D neural integrator proposed by Tweed and Vilis. The implications of this scheme for the control of binocular eye movements in three dimensions are discussed, along with possible neural correlates.

  20. Development of Grazing Incidence Optics for Neutron Imaging and Scattering (United States)

    Gubarev, M. V.; Khaykovich, B.; Liu, D.; Ramsey, B. D.; Zavlin, V. E.; Kilaru, K.; Romaine, S.; Rosati, R. E.; Bruni, R.; Moncton, D. E.


    Because of their wave nature, thermal and cold neutrons can be reflected from smooth surfaces at grazing incidence angles, be reflected by multilayer coatings or be refracted at boundaries of different materials. The optical properties of materials are characterized by their refractive indices which are slightly less than unity for most elements and their isotopes in the case of cold and thermal neutrons as well as for x-rays. The motivation for the optics use for neutrons as well as for x-rays is to increase the signal rate and, by virtue of the optic's angular resolution, to improve the signal-to-noise level by reducing the background so the efficiency of the existing neutron sources use can be significantly enhanced. Both refractive and reflective optical techniques developed for x-ray applications can be applied to focus neutron beams. Typically neutron sources have lower brilliance compared to conventional x-ray sources so in order to increase the beam throughput the neutron optics has to be capable of capturing large solid angles. Because of this, the replicated optics techniques developed for x-ray astronomy applications would be a perfect match for neutron applications, so the electroformed nickel optics under development at the Marshall Space Flight Center (MSFC) can be applied to focus neutron beams. In this technique, nickel mirror shells are electroformed onto a figured and superpolished nickel-plated aluminum cylindrical mandrel from which they are later released by differential thermal contraction. Cylindrical mirrors with different diameters, but the same focal length, can be nested together to increase the system throughput. The throughput can be increased further with the use of the multilayer coatings deposited on the reflectivr surface of the mirror shells. While the electroformed nickel replication technique needs to be adopted for neutron focusing, the technology to coat the inside of cylindrical mirrors with neutron multilayers has to be

  1. Grazing incidence optics; Proceedings of the Meeting, Orlando, FL, Apr. 3, 4, 1986 (United States)

    Osantowski, John F. (Editor); Van Speybroeck, Leon (Editor)


    Papers are presented on the diffraction-limited performance of grazing incidence optical systems; transverse ray aberrations of Wolter type 1 telescopes; hybrid X-ray telescope systems; surface characterization of grazing incidence optics in the extreme UV and X-ray regions; and the surface roughness properties of synchrotron radiation optics. Topics discussed include the simulation of free-abrasive grinding of grazing incidence mirrors with vertical-honing and flexible blades; mirrors for the Extreme Ultraviolet Explorer; the design and development of conical X-ray imaging mirrors; thermal loading considerations for synchrotron radiation mirrors; and grazing incidence optics for synchrotron radiation insertion-device beams. Consideration is given to the interpretation of glancing incidence scattering measurements; damage processes in short wavelength coated FEL optics; the replication of grain incidence optics; and the assembly and alignment of the Technology Mirror Assembly.

  2. Norms for hand-held rotary prism vergences. (United States)

    Wesson, M D; Amos, J F


    Norms of clinically useful techniques provide a means to measure and compare patient performance against a large clinical population of asymptomatic subjects. This study establishes mean values for vergence ranges (break and recovery) at 6 m and 40 cm using hand-held rotary prisms. Secondary effects of eye preference (dominance), order of prism presentation, and differences of results between clinicians were evaluated and found to have no statistical significance. This is another example of the trend to establish normal values for functions routinely measured in the optometric examination. Values are now available for the most commonly used vergence testing methods: the binocular rotary prism in the phoropter, the prism bar, and the handheld rotary prism. Testing can now be accomplished with or without a phoropter and comparisons can be made to normal values.

  3. Vector Disparity Sensor with Vergence Control for Active Vision Systems (United States)

    Barranco, Francisco; Diaz, Javier; Gibaldi, Agostino; Sabatini, Silvio P.; Ros, Eduardo


    This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that achieves high accuracy of the disparity computation around the fixation point, and fast reaction time for the vergence control. In this contribution, we address the development of a real-time architecture for vector disparity computation using an FPGA device. We implement the disparity unit and the control module for vergence, version, and tilt to determine the fixation point. In addition, two on-chip different alternatives for the vector disparity engines are discussed based on the luminance (gradient-based) and phase information of the binocular images. The multiscale versions of these engines are able to estimate the vector disparity up to 32 fps on VGA resolution images with very good accuracy as shown using benchmark sequences with known ground-truth. The performances in terms of frame-rate, resource utilization, and accuracy of the presented approaches are discussed. On the basis of these results, our study indicates that the gradient-based approach leads to the best trade-off choice for the integration with the active vision system. PMID:22438737

  4. A dual visual-local feedback model of the vergence eye movement system

    NARCIS (Netherlands)

    Erkelens, C.J.


    Pure vergence movements are the eye movements that we make when we change our binocular fixation between targets differing in distance but not in direction relative to the head. Pure vergence is slow and controlled by visual feedback. Saccades are the rapid eye movements that we make between targets

  5. Comparison of near fusional vergence ranges with rotary prisms and with prism bars. (United States)

    Goss, David A; Becker, Emily


    Common methods for determination of fusional vergence ranges make use of rotary prisms in the phoropter or prism bars out of the phoropter. This study compared near fusional vergence ranges with rotary prisms with those with prism bars. Fifty young adults served as subjects. Odd-numbered subjects had rotary prism vergences performed before prism bar vergences. For even-numbered subjects, prism bar vergences were done first. Base-in (BI) vergences were done before base-out (BO) vergences with both rotary prisms and prism bars. A coefficient of agreement was calculated by multiplying the standard deviation of the individual subject differences between rotary prisms and prism bars by 1.96, to approximate the range within which the 2 tests would agree 95% of the time. The lowest coefficient of agreement was 7.3Δ for the BI recovery. The others were high, ranging from 15.4Δ for the BO recovery to 19.5Δ for the BO break. Fusional vergence ranges determined by prism bars out of the phoropter cannot be used interchangeably with those determined by phoropter rotary prisms for the purpose of follow-up on individual patients or for the purpose of comparison with norms. Copyright © 2010 American Optometric Association. Published by Elsevier Inc. All rights reserved.

  6. Repeatability and agreement in the measurement of horizontal fusional vergences. (United States)

    Antona, B; Barrio, A; Barra, F; Gonzalez, E; Sanchez, I


    This study was designed to determine the repeatability of fusional vergence ranges measured using the rotary prisms in the phoropter and in free space using the prism bar. The level of agreement between the two methods was also investigated. In two separate sessions, negative and positive fusional vergence ranges (NFV and PFV, respectively) were measured at distance and near in 61 young adults (mean age 19.74, S.D. 2.5 years) who were unfamiliar with the methods used. Base-in and base-out blur, break and recovery points were sequentially determined. Both sets of measurements were obtained by the same examiner. At each distance, NFV was determined first and then PFV. The repeatability of the tests and agreement between measurements made with the phoropter rotary prisms and the prism bar were estimated by the Bland and Altman method. For both the phoropter rotary prisms and prism bar, NFV measurements showed better repeatability than PFV at both near and distance. Mean differences recorded for the NFV break and recovery points were non-significant (under 0.5Delta), while those observed for PFV were generally greater than 2Delta. When agreement between the two tests was assessed, it was found that break points were higher when determined using the phoropter rotary prisms, while recovery points were generally higher for the prism bar method. In clinical terms, according to the expected values of the NFV and PFV, agreement between the two techniques can be described as fair, because although mean differences were never greater than 5.5Delta, 95% agreement intervals were as wide as +/-8.00Delta for NFV and +/-13.19Delta for PFV. The two methods used to measure fusional vergences showed fairly good inter-session repeatability for measuring NFV but repeatability was reduced for PFV measurements. The level of agreement observed between the two methods was such that their interchangeable use in clinical practice is not recommended.

  7. The variation of torsion with vergence and elevation. (United States)

    Porrill, J; Ivins, J P; Frisby, J P


    Two recently developed kinematic models of human eye movements predict systematic departures from Listing's law which are associated with changes in vergence. This vergence-dependent torsion t is proportional to elevation e and vergence v, that is t = kev/2. The proposed value for k is either 1 (Van Rijn, L. J., & Van den Berg, A. V. (1993). Vision Research, 33, 691-708) or 1/2 (Minken, A. W. H., Gielen, C. C. A. M., & Van Gisbergen, J. A. M. (1995). Vision Research, 35, 93-102). One implication of both models is that an eye with a constant fixation direction should exhibit systematic torsional variation during movements of the other eye. This paper therefore examines the torsion produced by moving a fixation target inwards and outwards along the line-of-sight of the right eye at five different viewing elevations (0, +/- 15 and +/- 30 degrees). In a monocular analysis, each eye generally showed intorsion during convergence at positive elevation angles, whereas extorsion occurred at negative elevations; the opposite was true during divergence. However, the torsion response was visibly different between the five subjects, and depended on the direction of target motion. In a binocular analysis, cycloversion (mean of left and right eye torsion) varied dramatically both between subjects and between convergence and divergence; however, cyclovergence (torsional difference) was much less variable. Least-squares methods were used to estimate the constant k from monocular torsion, yielding values between 0.2 and 1.0; however, corresponding estimates based on cyclovergence were all close to 1/2. These findings support suggestions that a binocular control system couples the three-dimensional movements of the eyes, and that an existing model of monocular torsion should be generalised to the binocular case.

  8. Attentional Selection Accompanied by Eye Vergence as Revealed by Event-Related Brain Potentials.

    Directory of Open Access Journals (Sweden)

    Maria Sole Puig

    Full Text Available Neural mechanisms of attention allow selective sensory information processing. Top-down deployment of visual-spatial attention is conveyed by cortical feedback connections from frontal regions to lower sensory areas modulating late stimulus responses. A recent study reported the occurrence of small eye vergence during orienting top-down attention. Here we assessed a possible link between vergence and attention by comparing visual event related potentials (vERPs to a cue stimulus that induced attention to shift towards the target location to the vERPs to a no-cue stimulus that did not trigger orienting attention. The results replicate the findings of eye vergence responses during orienting attention and show that the strength and time of eye vergence coincide with the onset and strength of the vERPs when subjects oriented attention. Our findings therefore support the idea that eye vergence relates to and possibly has a role in attentional selection.

  9. Attentional Selection Accompanied by Eye Vergence as Revealed by Event-Related Brain Potentials. (United States)

    Sole Puig, Maria; Pallarés, Josep Marco; Perez Zapata, Laura; Puigcerver, Laura; Cañete, Josep; Supèr, Hans


    Neural mechanisms of attention allow selective sensory information processing. Top-down deployment of visual-spatial attention is conveyed by cortical feedback connections from frontal regions to lower sensory areas modulating late stimulus responses. A recent study reported the occurrence of small eye vergence during orienting top-down attention. Here we assessed a possible link between vergence and attention by comparing visual event related potentials (vERPs) to a cue stimulus that induced attention to shift towards the target location to the vERPs to a no-cue stimulus that did not trigger orienting attention. The results replicate the findings of eye vergence responses during orienting attention and show that the strength and time of eye vergence coincide with the onset and strength of the vERPs when subjects oriented attention. Our findings therefore support the idea that eye vergence relates to and possibly has a role in attentional selection.

  10. Interconverting the matrix and principal-meridional representations of dioptric power and reduced vergence. (United States)

    Harris, W F


    Converting the traditional representation of power as sphere, cylinder and axis to the dioptric power matrix F is usually performed by means of Long's equations and the reverse process by means of Keating's equations. It is sometimes useful to be able to convert directly between the matrix and power expressed in terms of principal powers F1 and F2 along corresponding principal meridians at angles a1 and a2. The equations for interconverting F and the principal-meridional representation expressed as F1(a1)F2 are presented here. Equivalent equations allow direct interconversion of the reduced vergence matrix L and the principal-meridional representation of vergence L1(a1)L2. Vergence becomes infinite at line and point focuses. Similarly effective power and back- and front-vertex power are infinite for some systems. Nevertheless it is possible unambiguously to represent infinite vergence and vertex power in principal-meridional form. However, information is usually lost in these infinite cases when the principal-meridional representation is converted to the matrix representation, and the former is not recoverable from the latter. As a consequence the matrix representation is usually unsatisfactory for vergences and vertex powers that are infinite. On the other hand, the principal-meridional representation of vergence and power is always satisfactory. If one adopts the position that effective powers and vertex powers are really vergences rather than powers then one concludes that the matrix provides a satisfactory representation for powers of thin systems in general but not for vergences. Implied by a vergence at a point is an interval of Sturm. The equations for characterizing the interval from the reduced vergence are presented.

  11. The Development of a Differential Deposition Technique for Figure Correction in Grazing Incidence Optics (United States)

    National Aeronautics and Space Administration — We propose the development of a physical-vapor-deposition coating technique to correct residual figure errors in grazing-incidence optics. The process involves...

  12. An Evaluation of Grazing-Incidence Optics for Neutron Imaging (United States)

    Gubarev, M. V.; Ramsey, B. D.; Engelhaupt, D. E.; Burgess, J.; Mildner, D. F. R.


    The focusing capabilities of neutron imaging optic based on the Wolter-1 geometry have been successfully demonstrated with a beam of long wavelength neutrons with low angular divergence.. A test mirror was fabricated using an electroformed nickel replication process at Marshall Space Flight Center. The neutron current density gain at the focal spot of the mirror is found to be at least 8 for neutron wavelengths in the range from 6 to 20 A. Possible applications of the optics are briefly discussed.

  13. Vergence eye movements made in response to spatial-frequency-filtered random-dot stereograms. (United States)

    Mowforth, P; Mayhew, J E; Frisby, J P


    Vergence responses were recorded from practised observers viewing narrow-band spatial-frequency-filtered planar random-dot stereograms. It was found that low spatial frequencies of 1.75-3.5 cycles deg-1 could trigger appropriate vergence responses to larger disparities than could the relatively high spatial frequency of 7.0 cycles deg-1. Nevertheless, appropriate vergence shifts were observed reliably for spatial-frequency/disparity combinations well outside the range predicted by Marr and Poggio's (1979) model of stereo vision. It was also found that for large-disparity/high-spatial-frequency combinations which the subjects could not fuse, the vergence system went into oscillation with the eyes diverging and converging at a frequency of about 1.5 Hz and with an amplitude of about 10-20 min arc. Finally, it was demonstrated that when a prominent monocular cue was superimposed upon a large-disparity/high-spatial-frequency stereogram then a speedy vergence response occurred which resulted in successful fusion. This latter finding supports the hypothesis advanced earlier that monocular cues can facilitate stereopsis by triggering appropriate vergence shifts.

  14. X-ray microscopy using grazing-incidence reflection optics

    International Nuclear Information System (INIS)

    Price, R.H.


    The Kirkpatrick-Baez microscopes are described along with their role as the workhorse of the x-ray imaging devices. This role is being extended with the development of a 22X magnification Kirkpatrick-Baez x-ray microscope with multilayer x-ray mirrors. These mirrors can operate at large angles, high x-ray energies, and have a narrow, well defined x-ray energy bandpass. This will make them useful for numerous experiments. However, where a large solid angle is needed, the Woelter microscope will still be necessary and the technology needed to build them will be useful for many other types of x-ray optics

  15. Differential Deposition for Surface Figure Corrections in Grazing Incidence X-Ray Optics (United States)

    Ramsey, Brian D.; Kilaru, Kiranmayee; Atkins, Carolyn; Gubarev, Mikhail V.; Broadway, David M.


    Differential deposition corrects the low- and mid- spatial-frequency deviations in the axial figure of Wolter-type grazing incidence X-ray optics. Figure deviations is one of the major contributors to the achievable angular resolution. Minimizing figure errors can significantly improve the imaging quality of X-ray optics. Material of varying thickness is selectively deposited, using DC magnetron sputtering, along the length of optic to minimize figure deviations. Custom vacuum chambers are built that can incorporate full-shell and segmented Xray optics. Metrology data of preliminary corrections on a single meridian of full-shell x-ray optics show an improvement of mid-spatial frequencies from 6.7 to 1.8 arc secs HPD. Efforts are in progress to correct a full-shell and segmented optics and to verify angular-resolution improvement with X-ray testing.

  16. Aplanatic telescopes based on Schwarzschild optical configuration: from grazing incidence Wolter-like x-ray optics to Cherenkov two-mirror normal incidence telescopes (United States)

    Sironi, Giorgia


    At the beginning of XX century Karl Schwarzschild defined a method to design large-field aplanatic telescopes based on the use of two aspheric mirrors. The approach was then refined by Couder (1926) who, in order to correct for the astigmatic aberration, introduced a curvature of the focal plane. By the way, the realization of normal-incidence telescopes implementing the Schwarzschild aplanatic configuration has been historically limited by the lack of technological solutions to manufacture and test aspheric mirrors. On the other hand, the Schwarzschild solution was recovered for the realization of coma-free X-ray grazing incidence optics. Wolter-like grazing incidence systems are indeed free of spherical aberration, but still suffer from coma and higher order aberrations degrading the imaging capability for off-axis sources. The application of the Schwarzschild's solution to X-ray optics allowed Wolter to define an optical system that exactly obeys the Abbe sine condition, eliminating coma completely. Therefore these systems are named Wolter-Schwarzschild telescopes and have been used to implement wide-field X-ray telescopes like the ROSAT WFC and the SOHO X-ray telescope. Starting from this approach, a new class of X-ray optical system was proposed by Burrows, Burg and Giacconi assuming polynomials numerically optimized to get a flat field of view response and applied by Conconi to the wide field x-ray telescope (WFXT) design. The Schwarzschild-Couder solution has been recently re-discovered for the application to normal-incidence Cherenkov telescopes, thanks to the suggestion by Vassiliev and collaborators. The Italian Institute for Astrophysics (INAF) realized the first Cherenkov telescope based on the polynomial variation of the Schwarzschild configuration (the so-called ASTRI telescope). Its optical qualification was successfully completed in 2016, demonstrating the suitability of the Schwarzschild-like configuration for the Cherenkov astronomy requirements

  17. Micropositioning in MAXIMUM: Photoemission microscopy with normal incident optics (abstract)

    International Nuclear Information System (INIS)

    Ng, W.; Wallace, J.P.; Ray-Chandhuri, A.K.; Capasso, C.; Cerrina, F.


    We discuss the two critical micropositioning systems implemented on the latest version of MAXIMUM at the Wisconsin Synchrotron Radiation Center. MAXIMUM is an undulator-based x-ray photoelectron microscope. The microscope utilizes a set of multilayer-coated normal incident Schwarzchild objective to produce a submicron focus spot. The sample is rastered across the spot and photoelectrons emitted from the sample are collected to form an image. The Schwarschild objective is mounted such that it is vibrationally isolated from the vacuum chamber. The two mirrors are mounted on a three axis flexural pivot stage actuated by inchworm motors. This system allows in situ fine alignment of the objective and it is totally decoupled from any vacuum forces. The inchworm motors will also act as clamps when the objective is aligned. The sample scanning is done by a flexural hinge stage actuated by an in-house design PZT stack. The stage has a range of 100 μmx100 μmx5 μm with a resolution of 100 A. The system is totally UHV compatible. A laser interferometer is used for sample position feedback. This work was supported by NSF, DOE

  18. Grazing-incidence optical magnetic recording with super-resolution. (United States)

    Scheunert, Gunther; Cohen, Sidney R; Kullock, René; McCarron, Ryan; Rechev, Katya; Kaplan-Ashiri, Ifat; Bitton, Ora; Dawson, Paul; Hecht, Bert; Oron, Dan


    Heat-assisted magnetic recording (HAMR) is often considered the next major step in the storage industry: it is predicted to increase the storage capacity, the read/write speed and the data lifetime of future hard disk drives. However, despite more than a decade of development work, the reliability is still a prime concern. Featuring an inherently fragile surface-plasmon resonator as a highly localized heat source, as part of a near-field transducer (NFT), the current industry concepts still fail to deliver drives with sufficient lifetime. This study presents a method to aid conventional NFT-designs by additional grazing-incidence laser illumination, which may open an alternative route to high-durability HAMR. Magnetic switching is demonstrated on consumer-grade CoCrPt perpendicular magnetic recording media using a green and a near-infrared diode laser. Sub-500 nm magnetic features are written in the absence of a NFT in a moderate bias field of only μ 0 H = 0.3 T with individual laser pulses of 40 mW power and 50 ns duration with a laser spot size of 3 μm (short axis) at the sample surface - six times larger than the magnetic features. Herein, the presence of a nanoscopic object, i.e., the tip of an atomic force microscope in the focus of the laser at the sample surface, has no impact on the recorded magnetic features - thus suggesting full compatibility with NFT-HAMR.

  19. Grazing-incidence optical magnetic recording with super-resolution

    Directory of Open Access Journals (Sweden)

    Gunther Scheunert


    Full Text Available Heat-assisted magnetic recording (HAMR is often considered the next major step in the storage industry: it is predicted to increase the storage capacity, the read/write speed and the data lifetime of future hard disk drives. However, despite more than a decade of development work, the reliability is still a prime concern. Featuring an inherently fragile surface-plasmon resonator as a highly localized heat source, as part of a near-field transducer (NFT, the current industry concepts still fail to deliver drives with sufficient lifetime. This study presents a method to aid conventional NFT-designs by additional grazing-incidence laser illumination, which may open an alternative route to high-durability HAMR. Magnetic switching is demonstrated on consumer-grade CoCrPt perpendicular magnetic recording media using a green and a near-infrared diode laser. Sub-500 nm magnetic features are written in the absence of a NFT in a moderate bias field of only μ0H = 0.3 T with individual laser pulses of 40 mW power and 50 ns duration with a laser spot size of 3 μm (short axis at the sample surface – six times larger than the magnetic features. Herein, the presence of a nanoscopic object, i.e., the tip of an atomic force microscope in the focus of the laser at the sample surface, has no impact on the recorded magnetic features – thus suggesting full compatibility with NFT-HAMR.

  20. Normative data for modified Thorington phorias and prism bar vergences from the Benton-IU study. (United States)

    Lyon, Don W; Goss, David A; Horner, Douglas; Downey, John P; Rainey, Bill


    The use of a phoropter for measuring phorias and vergences in children is common in the optometric profession. For young children, the use of the phoropter can be confusing, making it difficult to obtain accurate measurements. Free space testing allows for direct observation of the eyes in a natural environment and is easier for children to understand the directions. The normal values for phorias and vergences used with children are derived from testing with a phoropter or free space measurements with mostly adult patients. The Benton-IU Project was a large multidisciplinary study of factors affecting school performance conducted by the Indiana University School of Optometry and the Indiana University Department of Speech and Hearing with the cooperation of the Benton Community School Corporation (Benton County, Indiana). This project allowed the authors to obtain data on modified Thorington phorias and prism bar vergences from a nonselected group of first and fourth graders as part of an eye/vision examination. In this report, central tendency and variability statistics for modified Thorington and prism bar vergences are reported based on the data from the Benton-IU Study. The data presented in this report can be used by optometrists when deciding if the patient's phorias and vergences are within normal limits for children in the first through fourth grades.

  1. Vergence and Standing Balance in Subjects with Idiopathic Bilateral Loss of Vestibular Function.

    Directory of Open Access Journals (Sweden)

    Zoï Kapoula

    Full Text Available There is a natural symbiosis between vergence and vestibular responses. Deficits in vergence can lead to vertigo, disequilibrium, and postural instability. This study examines both vergence eye movements in patients with idiopathic bilateral vestibular loss, and their standing balance in relation to vergence. Eleven patients participated in the study and 16 controls. Bilateral loss of vestibular function was objectified with many tests; only patients without significant response to caloric tests, to video head impulse tests and without vestibular evoked myogenic potentials were included in the study.A LED display with targets at 20, 40, and 100 cm along the median plane was used to elicit vergence eye movements, recorded with the IRIS device.Four conditions were run, each lasting 1 min: fixation of a LED at 40 cm (convergence of 9°, at 150 cm (convergence of 2.3°; this last condition was repeated with eyes closed. Comparison of the eyes closed-eyes open conditions at 150 cm allowed evaluation of the Romberg Quotient. In the forth condition, two LEDS, at 20 and at 100 cm, were light on, one after the other for 1 sec, causing the eyes to converge then diverge. Standing balance was recorded with an accelerometer placed at the back near the center of mass (McRoberts, Dynaport.Relative to controls, convergence eye movements in patients showed significantly lower accuracy, lower mean velocity, and saccade intrusions of significantly higher amplitude.The normalized 90% area of body sway was significantly higher for patients than for controls for all conditions. Yet, similarly to controls, postural stability was better while fixating at near (sustained convergence than at far, or while making active vergence movements. We argue that vestibular loss deteriorates convergence, but even deficient, convergence can be helpful for postural control.

  2. Vergence and Standing Balance in Subjects with Idiopathic Bilateral Loss of Vestibular Function. (United States)

    Kapoula, Zoï; Gaertner, Chrystal; Yang, Qing; Denise, Pierre; Toupet, Michel


    There is a natural symbiosis between vergence and vestibular responses. Deficits in vergence can lead to vertigo, disequilibrium, and postural instability. This study examines both vergence eye movements in patients with idiopathic bilateral vestibular loss, and their standing balance in relation to vergence. Eleven patients participated in the study and 16 controls. Bilateral loss of vestibular function was objectified with many tests; only patients without significant response to caloric tests, to video head impulse tests and without vestibular evoked myogenic potentials were included in the study. A LED display with targets at 20, 40, and 100 cm along the median plane was used to elicit vergence eye movements, recorded with the IRIS device. Four conditions were run, each lasting 1 min: fixation of a LED at 40 cm (convergence of 9°), at 150 cm (convergence of 2.3°); this last condition was repeated with eyes closed. Comparison of the eyes closed-eyes open conditions at 150 cm allowed evaluation of the Romberg Quotient. In the forth condition, two LEDS, at 20 and at 100 cm, were light on, one after the other for 1 sec, causing the eyes to converge then diverge. Standing balance was recorded with an accelerometer placed at the back near the center of mass (McRoberts, Dynaport). Relative to controls, convergence eye movements in patients showed significantly lower accuracy, lower mean velocity, and saccade intrusions of significantly higher amplitude. The normalized 90% area of body sway was significantly higher for patients than for controls for all conditions. Yet, similarly to controls, postural stability was better while fixating at near (sustained convergence) than at far, or while making active vergence movements. We argue that vestibular loss deteriorates convergence, but even deficient, convergence can be helpful for postural control.

  3. Modulation of vergence by off-vertical yaw axis rotation in the monkey: normal characteristics and effects of space flight (United States)

    Dai, M.; Raphan, T.; Kozlovskaya, I.; Cohen, B.


    Horizontal movements of both eyes were recorded simultaneously using scleral search coils in 2 rhesus monkeys before and after the COSMOS 2229 space-flight of 1992-1993. Another 9 monkeys were tested at comparable time intervals and served as controls. Ocular vergence, defined as the difference in horizontal position between the left and right eyes, was measured during off-vertical yaw axis rotation (OVAR) in darkness. Vergence was modulated sinusoidally as a function of head position with regard to gravity during OVAR. The amplitude of peak-to-peak modulation increased with increments in tilt of the angle of the rotational axis (OVAR tilt angle) that ranged from 15 degrees to 90 degrees. Of the 11 monkeys tested, 1 had no measurable modulation in vergence. In the other 10, the mean amplitude of the peak to peak modulation was 5.5 degrees +/- 1.3 degrees at 90 degrees tilt. Each of these monkeys had maximal vergence when its nose was pointed close to upward (gravity back; mean phase: -0.9 degree +/- 26 degrees). After space flight, the modulation in vergence was reduced by over 50% for the two flight monkeys, but the phase of vergence modulation was not altered. The reduction in vergence modulation was sustained for the 11-day postflight testing period. We conclude that changes in vergence are induced in monkeys by the sinusoidal component of gravity acting along the naso-occipital axis during yaw axis OVAR, and that the modulation of the vergence reflex is significantly less sensitive to linear acceleration after space flight.

  4. Partially coherent X-ray wavefront propagation simulations including grazing-incidence focusing optics. (United States)

    Canestrari, Niccolo; Chubar, Oleg; Reininger, Ruben


    X-ray beamlines in modern synchrotron radiation sources make extensive use of grazing-incidence reflective optics, in particular Kirkpatrick-Baez elliptical mirror systems. These systems can focus the incoming X-rays down to nanometer-scale spot sizes while maintaining relatively large acceptance apertures and high flux in the focused radiation spots. In low-emittance storage rings and in free-electron lasers such systems are used with partially or even nearly fully coherent X-ray beams and often target diffraction-limited resolution. Therefore, their accurate simulation and modeling has to be performed within the framework of wave optics. Here the implementation and benchmarking of a wave-optics method for the simulation of grazing-incidence mirrors based on the local stationary-phase approximation or, in other words, the local propagation of the radiation electric field along geometrical rays, is described. The proposed method is CPU-efficient and fully compatible with the numerical methods of Fourier optics. It has been implemented in the Synchrotron Radiation Workshop (SRW) computer code and extensively tested against the geometrical ray-tracing code SHADOW. The test simulations have been performed for cases without and with diffraction at mirror apertures, including cases where the grazing-incidence mirrors can be hardly approximated by ideal lenses. Good agreement between the SRW and SHADOW simulation results is observed in the cases without diffraction. The differences between the simulation results obtained by the two codes in diffraction-dominated cases for illumination with fully or partially coherent radiation are analyzed and interpreted. The application of the new method for the simulation of wavefront propagation through a high-resolution X-ray microspectroscopy beamline at the National Synchrotron Light Source II (Brookhaven National Laboratory, USA) is demonstrated.

  5. A three-dimensional analysis of vergence movements at various levels of elevation. (United States)

    Minken, A W; Van Gisbergen, J A


    Earlier studies have shown that eye positions, recorded in subjects scanning a distant visual scene with the head in a stable position, have only two degrees of freedom (Listing's law). Due to cyclovergence, this law is modified in near-vision. Two previous quantitative studies have documented that the sign of the torsional vergence component depends systematically on elevation: when fixating a nearby target, the eyes show intorsion in up gaze, extorsion in down gaze and no cyclotorsion at some intermediate elevation level (to be denoted as the null elevation). Both studies found a linear cyclovergence/elevation relation, but disagreed on the amount of cyclotorsion. A further uncertainty is how this phenomenon develops dynamically when the binocular fixation point shifts from a far to a near position. Therefore, we have investigated the dynamic coupling between the horizontal and torsional components of vergence in human subjects who were instructed to refixate a light target after it stepped in depth. The target steps were presented at various vertical and horizontal directions relative to the straight-ahead axis of the cyclopean eye. We found that the quantitative relations among horizontal vergence, torsional vergence and elevation were intermediate between those found in the two earlier near-vision studies and that they correspond reasonably to the predictions of a model by Mok and co-workers. The cyclotorsion vergence component had about the same latency and dynamics as the horizontal component. When refixations were studied at different elevations, the torsional vergence component changed from incyclotorsion in up gaze to excyclotorsion in down gaze. In agreement with expectations derived from two quantitative models, the null elevation of cyclovergence was near the binocular primary position. Furthermore, we found no consistent additional dependence on the horizontal direction of the refixation trajectory relative to the midsaggital plane. Other experiments

  6. The distribution of near point of convergence, near horizontal heterophoria, and near vergence among myopic children in South Korea


    Jang, Jung Un; Park, Inn-Jee; Jang, Jung Yun


    Background/Purpose: To assess the distribution of near point of convergence (NPC), near heterophoria, and near vergence among myopic school children in South Korea. Methods: One hundred and thirty-six elementary school children, aged 8–13 years, were each given a thorough eye examination including binocular vision testing, NPC using standard push-up technique, horizontal heterophoria measurement by Von Graefe, distance, and near negative and positive vergence with a phoropter and phoropter re...

  7. Symmetry consideration in zero loop-area Sagnac interferometry at oblique incidence for detecting magneto-optic Kerr effects. (United States)

    Zhu, X D


    I present a detailed account of a zero loop-area Sagnac interferometer operated at oblique incidence for detecting magneto-optic Kerr effects arising from a magnetized sample. In particular, I describe the symmetry consideration and various optical arrangements available to such an interferometer that enables measurements of magneto-optic effects due to both in-plane and out-of-plane magnetization of the sample with optimizable signal-to-noise ratios.

  8. Using Weightless Neural Networks for Vergence Control in an Artificial Vision System

    Directory of Open Access Journals (Sweden)

    Karin S. Komati


    Full Text Available This paper presents a methodology we have developed and used to implement an artificial binocular vision system capable of emulating the vergence of eye movements. This methodology involves using weightless neural networks (WNNs as building blocks of artificial vision systems. Using the proposed methodology, we have designed several architectures of WNN-based artificial vision systems, in which images captured by virtual cameras are used for controlling the position of the ‘foveae’ of these cameras (high-resolution region of the images captured. Our best architecture is able to control the foveae vergence movements with average error of only 3.58 image pixels, which is equivalent to an angular error of approximately 0.629°.

  9. Normal Speed and Accuracy of Saccade and Vergence Eye Movements in Dyslexic Reader Children

    Directory of Open Access Journals (Sweden)

    Maria Pia Bucci


    Full Text Available Objective. Latency of eye movements depends on cortical structures while speed of execution and accuracy depends mostly on subcortical brainstem structures. Prior studies reported in dyslexic reader children abnormalities of latencies of saccades (isolated and combined with vergence; such abnormalities were attributed to deficits of fixation control and of visual attention. In this study we examine speed and accuracy characteristics of horizontal eye movements in natural space (saccades, vergence and combined movements in dyslexic reader children. Methods. Two paradigms are tested: gap paradigm (fixation offset 200 ms prior to target onset, producing shorter latencies, in both non-dyslexic reader and dyslexic reader children and simultaneous paradigm. Seventeen dyslexic reader children (mean age: 12±0.08 years and thirteen non-dyslexic reader children (mean age: 12±1 years were tested. Horizontal eye movements from both eyes were recorded simultaneously by a photoelectric device (Oculometer, Dr. Bouis. Results. For all movements tested (saccades, vergence, isolated or combined and for both paradigms, the mean velocity and accuracy were similar in dyslexic readers and non-dyslexic readers; no significant difference was found. Conclusion. This negative but important result, suggests no dysfunction of brainstem ocular motor circuits in dyslexic readers. It contrasts results on latencies related to visual attention dysfunction at cortical level.

  10. Reading performance is not affected by a prism induced increase of horizontal and vertical vergence demand

    Directory of Open Access Journals (Sweden)

    Muriel eDysli


    Full Text Available Purpose Dyslexia is the most common developmental reading disorder that affects language skills. Latent strabismus (heterophoria has been suspected to be causally involved. Even though phoria correction in dyslexic children is commonly applied, the evidence in support of a benefit is poor. In order to provide experimental evidence on this issue, we simulated phoria in healthy readers by modifying the vergence tone required to maintain binocular alignment. MethodsVergence tone was altered with prisms that were placed in front of one eye in 16 healthy subjects to induce exophoria, esophoria, or vertical phoria. Subjects were to read one paragraph for each condition, from which reading speed was determined. Text comprehension was tested with a forced multiple choice test. Eye movements were recorded during reading and subsequently analysed for saccadic amplitudes, saccades per 10 letters, percentage of regressive (backward saccades, average fixation duration, first fixation duration on a word, and gaze duration.ResultsAcute change of horizontal and vertical vergence tone does neither significantly affect reading performance nor reading associated eye movements. Conclusion Prisms in healthy subjects fail to induce a significant change of reading performance. This finding is not compatible with a role of phoria in dyslexia. Our results contrast the proposal for correcting small angle heterophorias in dyslexic children.

  11. Optimization of Grazing Incidence Optics for Wide-Field X-Ray Survey Imaging (United States)

    Roming, P. W. A.; Burrows, D. N.; Garmire, G. P.; Roush, W. B.


    Optimization of wide-field X-ray optics could greatly enhance X-ray surveys. Discussions of optimizing wide-field X-ray optics, with field-of-views less-than 1.1 degree-squared, have been made previously in the literature. However, very little has been published about the optimizing of wide-field X-ray optics with larger fields-of-view. We have been working on the design of a wide-field (3.1 degree-squared field-of-view), short focal length (190.5 cm), grazing incidence mirror shell set, with a desired rms image spot size of 15 arcsec. The baseline design incorporates Wolter I type mirror shells with polynomial perturbations applied to the grazing incidence surface. By optimizing the polynomial, the rms image spot size can be minimized for a large range of grazing angles. The overall minimization technique is to efficiently optimize the polynomial coefficients that directly influence the angular resolution, without stepping through the entire multidimensional coefficient space. The multidimensional minimization techniques that have been investigated include: the downhill simplex method; the coupling of genetic algorithms with full and fractional, including Plackett-Burman, factorial designs; and the coupling of genetic algorithms with Box-Behnken and central composite response surface designs. We have also examined the use of neural networks, coupled with genetic algorithms, as a method of multidimensional minimization. Investigations of backpropagation, probabilistic (PNN), general regression (GRNN), and group method of data handling (GMDH) neural networks have been made. We report our findings to date. This research is funded by NASA grant #NAG5-5093.

  12. Distinct control of initiation and metrics of memory-guided saccades and vergence by the FEF: a TMS study. (United States)

    Yang, Qing; Kapoula, Zoi


    The initiation of memory guided saccades is known to be controlled by the frontal eye field (FEF). Recent physiological studies showed the existence of an area close to FEF that controls also vergence initiation and execution. This study is to explore the effect of transcranial magnetic simulation (TMS) over FEF on the control of memory-guided saccade-vergence eye movements. Subjects had to make an eye movement in dark towards a target flashed 1 sec earlier (memory delay); the location of the target relative to fixation point was such as to require either a vergence along the median plane, or a saccade, or a saccade with vergence; trials were interleaved. Single pulse TMS was applied on the left or right FEF; it was delivered at 100 ms after the end of memory delay, i.e. extinction of fixation LED that was the "go" signal. Twelve healthy subjects participated in the study. TMS of left or right FEF prolonged the latency of all types of eye movements; the increase varied from 21 to 56 ms and was particularly strong for the divergence movements. This indicates that FEF is involved in the initiation of all types of memory guided movement in the 3D space. TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF. The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

  13. Accommodation and vergence status among the 3rd and 4th graders in a mainstream school in Gauteng*

    Directory of Open Access Journals (Sweden)

    I. T. Metsing


    Full Text Available Aim: The data presented in this paper is obtained from the study on the prevalence of visual deficien-cies in mainstream and learning disabled schools which revealed no difference in the prevalence of visual deficiencies in both schools. One of the objectives of this study was to determine the visual status of each learner in each of the two groups (mainstream and learning disabled. The findings of the study revealed that both groups presented with different visual deficiencies including accommodation, vergence deficiencies and poor ocular motilities which can contribute towards influencing the children’s learning skills negatively. The visual profile on the accommodative and vergence systems of the children from the mainstream school is further analysed in this paper to determine the prevalence of deficiencies in the 8-13 year-olds, and to support inclusion of the evaluation of these visual skills in the school vision screening protocol. Method: One hundred and twelve (112 children had an expanded vision screening, with eighty (80 from the mainstream school in Johannesburg aged 8-13 years. The expanded vision screeningincluded the measurement of visual acuity (Snellen Acuity, refractive error (static retinoscopy, accommodation (accuracy, facility and amplitude, evaluation of the vergence system (accuracy, facility and amplitude and ocular motilities (direct ob-servation. Of the 80 children from the mainstream school, only 73 children’s results were consideredlearning performance of children, especially those of school-going-age. The study therefore supports the expanded vision screening of all school-going-children in South Africa to include visual efficiency skills (accommodation and vergence systems for appropriate and early identification of the barriers and seven subjects were excluded due to their poor responses to the tests.Kolmogorov-Smirnov test was utilized to assess the normality of distribution of accommodative and vergence

  14. The distribution of near point of convergence, near horizontal heterophoria, and near vergence among myopic children in South Korea. (United States)

    Jang, Jung Un; Park, Inn-Jee; Jang, Jung Yun


    To assess the distribution of near point of convergence (NPC), near heterophoria, and near vergence among myopic school children in South Korea. One hundred and thirty-six elementary school children, aged 8-13 years, were each given a thorough eye examination including binocular vision testing, NPC using standard push-up technique, horizontal heterophoria measurement by Von Graefe, distance, and near negative and positive vergence with a phoropter and phoropter replacement card. NPC break and recovery points were highest in the age 9 years group, but the mean values of NPC were within the normal range. Of 136 individuals, 52 presented with esophoria, 53 presented with 0 -6-Δ exophoria, and 31 presented with ≥7-Δ exophoria. In the younger age groups (8 years and 10 years) 0-6-Δ exophoria was prevalent, whereas in the older age groups (11 years, 12 years, and 13 years) esophoria was prevalent. Near positive fusional vergence (break and recovery point) presented with statistically significant correlations with the participants' ages. Esophoria showed higher correlations with high myopia (8.00 ± 0.000) rather than with low myopia (3.36 ± 2.499) or medium myopia (3.42 ± 2.149). The mean value of 0-6Δ exophoria was highest in medium myopia (4.04 ± 1.517), and of ≥7-Δ exophoria was the highest in high myopia (12.66 ± 1.154). There were no statistically significant correlations between the school childrens' ages and NPC, near horizontal heterophoria, and near fusional vergence, except near positive fusional vergence. Also, unlike many studies, myopic magnitude did not present a significant correlation with near phoria and fusional vergence.

  15. Dissociated vertical deviation and eye torsion: Relation to disparity-induced vertical vergence. (United States)

    Van Rijn, L J; Simonsz, H J; Tusscher, M P


    We studied the relation between vertical eye movements and binocular torsion in five subjects with dissociated vertical deviation (DVD). During trials, subject viewed a well illuminated Snellen letter chart, with both eyes uncovered during 4 seconds, Subsequently, DVD was induced by covering one eye during 4 seconds. Finally, both eyes were uncovered during 4 seconds. Several trials were recorded for each subject and covered eye. Eye movements were measured with scleral coils. We found that in all subjects, the vertical divergence followed an exponential course with a time constant of 0.67 ± 0.14 seconds on average. In three of the five subjects this vertical divergence was associated with binocular torsion (cycloversion), partly, in the form of a cycloversional nystagmus. The time course of the vertical divergence as well as the direction and nystagmic nature of the cycloversion was similar to the behaviour that was previously observed in disparity induced vertical vergence in normal subjects. In two of the subjects, the torsion that was associated with the vertical divergence was monocular. Our results indicate that DVD and disparity induced vertical vergence share the same characteristics. In addition, they demonstrate that extorsion associated with the elevation in DVD possibly but not necessarily points at a dissociated torsional deviation.

  16. Fusional Vergence Detected by Prism Bar and Synoptophore in Chinese Childhood Intermittent Exotropia

    Directory of Open Access Journals (Sweden)

    Tao Fu


    Full Text Available Purpose. To measure the changes in fusional vergence in Chinese children with intermittent exotropia (IXT and the association with the control of IXT. Methods. Ninety-two patients with IXT (8–15 years old were compared with 86 controls. Exodeviation control was evaluated using the Revised Newcastle Control Score. Angle of deviation was measured using prism and alternate cover testing at distance and near. Fusional vergence was measured using prism bar and synoptophore. This study was registered with ChiCTR-RCC-13003920. Results. Using prism bar, convergence break points were lower whereas divergence break points were higher in children with IXT at distance (P<0.001 and near (P<0.001 compared with controls. There was no significant difference in mean divergence amplitudes between the two groups when testing using a synoptophore (P=0.53. In children with IXT, the distance between recovery point and break point in both convergence (distance: P=0.02; near: P=0.02 and divergence (distance: P<0.001; near: P<0.001 was larger than controls when detected by prism bar and synoptophore (convergence: P=0.005; divergence: P=0.006. Conclusions. Children with IXT have reduced convergence amplitudes as detected by both prism bar and synoptophore.

  17. Reflective afocal broadband adaptive optics scanning ophthalmoscope (United States)

    Dubra, Alfredo; Sulai, Yusufu


    A broadband adaptive optics scanning ophthalmoscope (BAOSO) consisting of four afocal telescopes, formed by pairs of off-axis spherical mirrors in a non-planar arrangement, is presented. The non-planar folding of the telescopes is used to simultaneously reduce pupil and image plane astigmatism. The former improves the adaptive optics performance by reducing the root-mean-square (RMS) of the wavefront and the beam wandering due to optical scanning. The latter provides diffraction limited performance over a 3 diopter (D) vergence range. This vergence range allows for the use of any broadband light source(s) in the 450-850 nm wavelength range to simultaneously image any combination of retinal layers. Imaging modalities that could benefit from such a large vergence range are optical coherence tomography (OCT), multi- and hyper-spectral imaging, single- and multi-photon fluorescence. The benefits of the non-planar telescopes in the BAOSO are illustrated by resolving the human foveal photoreceptor mosaic in reflectance using two different superluminescent diodes with 680 and 796 nm peak wavelengths, reaching the eye with a vergence of 0.76 D relative to each other. PMID:21698035

  18. Adjustable Grazing Incidence X-ray Optics with 0.5 Arc Second Resolution (United States)

    Reid, Paul

    We seek to develop adjustable grazing incidence optics for x-ray astronomy. The goal of this development is thin, lightweight mirrors with angular resolution of 0.5 arc seconds, comparable to the Chandra X-ray Observatory. The new mirror design consists of thin segments of a Wolter-I grazing incidence mirror, with piezo-electric material deposited directly on the back surface of the mirror. Depositing a pattern of independently addressable electrodes on top of the piezoelectric material produces an array of independent piezo cells. Energizing a particular cell introduces a localized deformation in the mirror without the need for a reaction structure. By applying the appropriate voltage to the piezo cells, it is possible to correct mirror figure errors that result from mirror fabrication, gravity release, mounting, and thermal effects. Because the thin mirrors segments are lightweight, they can be densely nested to produce collecting area thirty times that of Chandra, on an affordably priced mission. This Supporting Technology program is a follow-on to an existing APRA program. In the existing program we demonstrated the first successful deposition of piezoelectric material on thermally formed glass substrates. We showed that the localized deformations produced by the piezo cells match finite element predictions, and the piezo cell adjustment range meets requirements necessary to achieve the desired figure correction. We have also shown through simulation that representative mirror figure errors can be corrected via modeled influence functions to achieve 0.5 arc sec imaging performance. This provides a firm foundation on which to develop further the technology. We will continue to optimize the deposition of thin piezoelectric films onto thermally formed glass and electroplated metal mirror segments to improve yield and manufacturability. We will deposit piezoelectric material onto conical mirror segments and demonstrate figure correction in agreement with prediction

  19. Distinct control of initiation and metrics of memory-guided saccades and vergence by the FEF: a TMS study.

    Directory of Open Access Journals (Sweden)

    Qing Yang

    Full Text Available BACKGROUND: The initiation of memory guided saccades is known to be controlled by the frontal eye field (FEF. Recent physiological studies showed the existence of an area close to FEF that controls also vergence initiation and execution. This study is to explore the effect of transcranial magnetic simulation (TMS over FEF on the control of memory-guided saccade-vergence eye movements. METHODOLOGY/PRINCIPAL FINDINGS: Subjects had to make an eye movement in dark towards a target flashed 1 sec earlier (memory delay; the location of the target relative to fixation point was such as to require either a vergence along the median plane, or a saccade, or a saccade with vergence; trials were interleaved. Single pulse TMS was applied on the left or right FEF; it was delivered at 100 ms after the end of memory delay, i.e. extinction of fixation LED that was the "go" signal. Twelve healthy subjects participated in the study. TMS of left or right FEF prolonged the latency of all types of eye movements; the increase varied from 21 to 56 ms and was particularly strong for the divergence movements. This indicates that FEF is involved in the initiation of all types of memory guided movement in the 3D space. TMS of the FEF also altered the accuracy but only for leftward saccades combined with either convergence or divergence; intrasaccadic vergence also increased after TMS of the FEF. CONCLUSIONS/SIGNIFICANCE: The results suggest anisotropy in the quality of space memory and are discussed in the context of other known perceptual motor anisotropies.

  20. Variation and correlation of standard clinical phoropter tests of phorias, vergence ranges, and relative accommodation in a sample of school-age children. (United States)

    Jackson, T W; Goss, D A


    This paper presents a study of standard clinical phoropter tests of dissociated phorias, fusional vergence ranges, and relative accommodation ranges in 244 school-age (7.9 to 15.9 years of age) children. The tests studied included von Graefe phorias and base-in and base-out fusional vergence ranges at both distance and near, as well as negative relative accommodation (NRA) and positive relative accommodation (PRA) tests. Coefficients of correlation among the various tests are presented. Means and correlations were similar to those previously reported for adult populations. Distributions of distance lateral phorias and some distance fusional vergence parameters were leptokurtic.

  1. Computer-Controlled Cylindrical Polishing Process for Development of Grazing Incidence Optics for Hard X-Ray Region (United States)

    Khan, Gufran Sayeed; Gubarev, Mikhail; Speegle, Chet; Ramsey, Brian


    The presentation includes grazing incidence X-ray optics, motivation and challenges, mid spatial frequency generation in cylindrical polishing, design considerations for polishing lap, simulation studies and experimental results, future scope, and summary. Topics include current status of replication optics technology, cylindrical polishing process using large size polishing lap, non-conformance of polishin lap to the optics, development of software and polishing machine, deterministic prediction of polishing, polishing experiment under optimum conditions, and polishing experiment based on known error profile. Future plans include determination of non-uniformity in the polishing lap compliance, development of a polishing sequence based on a known error profile of the specimen, software for generating a mandrel polishing sequence, design an development of a flexible polishing lap, and computer controlled localized polishing process.

  2. Dynamic model of the vergence eye movement system: simulations using MATLAB/SIMULINK. (United States)

    Hung, G K


    A dynamic model of the vergence eye movement system was developed and simulated using MATLAB/SIMULINK. The model was based on a dual-mode dynamic model previously written in FORTRAN. It consisted of a fast open-loop component and a slow closed-loop component. The new model contained several important modifications. For example, in the fast component, a zero-order hold element replaced the sampler and the target trajectory estimator in the earlier model to provide more stable and accurate responses. Also, a periodicity detector was added to automatically detect periodicity in the stimulus waveform. The stored periodic stimulus, with a reduction in latency, was used to drive the fast component output. Moreover, a connection representing the efference copy signal was added from the fast component output to the disparity input to provide an accurate estimate of the stimulus waveform. Further, Robinson's model of the extraocular muscles replaced the earlier 2nd-order plant to provide more realistic muscle dynamics. The entire model, containing the fast and slow components, was simulated using a variety of stimuli such as pulses, positive and negative ramps, square-wave, and sine-wave. The responses showed dynamic characteristics similar to experimental results. Thus, this new MATLAB/SIMULINK program provides a relatively easy-to-use, versatile, and powerful simulation environment for investigating the basic as well as clinical aspects of vergence dynamics. Moreover, the simulation program has general characteristics that can be modified to represent other oculomotor systems such as the versional and accommodation systems. This provides a framework for future investigation of dynamic interactions between oculomotor systems.

  3. Incidence and Outcomes of Optical Zone Enlargement and Recentration After Previous Myopic LASIK by Topography-Guided Custom Ablation. (United States)

    Reinstein, Dan Z; Archer, Timothy J; Carp, Glenn I; Stuart, Alastair J; Rowe, Elizabeth L; Nesbit, Andrew; Moore, Tara


    To report the incidence, visual and refractive outcomes, optical zone enlargement, and recentration using topography-guided CRS-Master TOSCA II software with the MEL 80 excimer laser (Carl Zeiss Meditec AG, Jena, Germany) after primary myopic laser refractive surgery. Retrospective analysis of 73 eyes (40 patients) with complaints of night vision disturbances due to either a decentration or small optical zone following a primary myopic laser refractive surgery procedure using the MEL 80 laser. Multiple ATLAS topography scans were imported into the CRS-Master software for topography-guided ablation planning. The topography-guided re-treatment procedure was performed as either a LASIK flap lift, a new LASIK flap, a side cut only, or photorefractive keratectomy. Axial curvature maps were analyzed using a fixed grid and set of concentric circles superimposed to measure the topographic optical zone diameter and centration. Follow-up was 12 months. The incidence of use in the population of myopic treatments during the study period was 0.79% (73 of 9,249). The optical zone diameter was increased by 11% from a mean of 5.65 to 6.32 mm, with a maximum change of 2 mm in one case. Topographic decentration was reduced by 64% from a mean of 0.58 to 0.21 mm. There was a 44% reduction in spherical aberration, 53% reduction in coma, and 39% reduction in total higher order aberrations. A subjective improvement in night vision symptoms was reported by 93%. Regarding efficacy, 82% of eyes reached 20/20 and 100% reached 20/32 (preoperative CDVA was 20/20 or better in 90%). Regarding safety, no eyes lost two lines of CDVA and 27% gained one line. Regarding predictability, 71% of re-treatments were within ±0.50 diopters. Topography-guided ablation was effective in enlarging the optical zone, recentering the optical zone, and reducing higher order aberrations. Topography-guided custom ablation appears to be an effective method for re-treatment procedures of symptomatic patients after

  4. Dependence of optical properties of monoclinic MnWO{sub 4} on the electric field of incident light

    Energy Technology Data Exchange (ETDEWEB)

    Cai Lugang [School of Physics and Nuclear Energy Engineering, Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education), Beihang University, Beijing 100191 (China); Liu Famin, E-mail: [School of Physics and Nuclear Energy Engineering, Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education), Beihang University, Beijing 100191 (China); Zhang Dian; Zhong Wenwu [School of Physics and Nuclear Energy Engineering, Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education), Beihang University, Beijing 100191 (China)


    Considering the electric field of incident light along four particular directions [100], [110], [011], and [010], the optical properties of monoclinic MnWO{sub 4} were investigated by the first-principle methods. The calculated electronic structures show that the O 2p states and Mn 3d states dominate the top of the valence bands, while the W 5d and Mn 3d states play a key role in the bottom of the conduction bands. The dielectric function and other optical properties, including absorption coefficient, reflectivity spectra, and energy-loss spectra, were calculated and analyzed. The results predicted the maximum static dielectric function when the electric field of incident light was along the [100] direction; meanwhile the absorption edge was calculated to be consistent with the energy band gap and the values and positions of peaks in absorption coefficient are related with the electric field of light. Otherwise, it is found that the appearance of peaks in the energy-loss spectra is also dependent on the electric field and simultaneously corresponds to the edge of absorption spectra and the peaks' position of reflectivity spectra.

  5. Evaluation of Ocular Accommodation, Convergence and Fusional Vergence Changes during Ramadan

    Directory of Open Access Journals (Sweden)

    Seyed Hosein Hoseini-Yazdi


    Full Text Available Purpose: There are a few researches regarding the effects of Islamic fasting on visual system. The aim of this study was to investigate the effects of Ramadan fasting on the amplitude of accommodation (AA, near point of convergence (NPC, positive and negative fusional vergences (PFV and NFV, respectively in visually healthy fasters. Methods: AA, NPC, PFV and NFV at far (6m and near (40cm were measured in 30 male students. Nutritional habits in a week before each examination visit were assessed with the Food Frequency Questionnaire (FFQ. Results: Mean age and fasting average experience were 23.9 and 10 years, respectively. AA and NPC showed significant changes (p<0.05 during Ramadan; but there was no significant difference before and after Ramadan in these parameters. NFV blur, break and recovery points at far significantly reduced in Ramadan than before (p=0.003, p=0.005, p=0.003, respectively with insignificant compensation after Ramadan. Results showed that there was no significant correlation between changes in diet pattern and AA, NPC and distant NFV variations (p<0.05. Conclusion: Some visual problems may be reported at far and near visual tasks during Ramadan; but most of the problems may be resolved after it. Some visual preparations may be needed for more effective visual activities during Ramadan; essentially for students with intensive visual tasks. Vision therapy may be suggested along with nutrient pattern improvement during Ramadan.

  6. A new optical method for measuring surface temperature at large incident probe angles (United States)

    Lee, A. S.; Norris, P. M.


    A novel thermoreflectance technique has been developed for noncontact temperature measurements using laser light incident at large angles on solid materials and devices. The method involves measuring the differential reflectance from a polarization modulated laser beam. The polarization differential reflectance technique is demonstrated on single-crystal Si wafers and on a polycrystalline carbon thin film over a temperature range of 20-60 °C. The method is shown to be an extremely sensitive temperature probe for near grazing angle measurements, which could be useful for monitoring the surface temperature of closely stacked silicon wafers used in batch processing in the microelectronics industry.

  7. Mounting for Fabrication, Metrology, and Assembly of Full Shell Grazing Incidence Optics (United States)

    Roche, Jacqueline M.; Gubarev, Mikhail V.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Ramsey, Brian D.; Elsner, Ronald F.


    Future x-ray telescopes will likely require lightweight mirrors to attain the large collecting areas needed to accomplish the science objectives. Understanding and demonstrating processes now is critical to achieving sub-arcsecond performance in the future. Consequently, designs not only of the mirrors but of fixtures for supporting them during fabrication, metrology, handling, assembly, and testing must be adequately modeled and verified. To this end, MSFC is using finite-element modeling to study the effects of mounting on full-shell grazing-incidence mirrors, during all processes leading to flight mirror assemblies. Here we report initial results of this study.

  8. AXAF optical technology analysis. [effects of alignment figure errors on the performance of grazing incidence telescopes (United States)

    Korsch, D.


    A grazing incidence telescope with six nested subsystems is investigated through the effects of misalignment and surface deformations on it's image quality. The axial rms-spot size serves as measure for the image quality. The surface deformations are simulated by ellipsoidal and sinusoidal deviation elements. Each type of defect is analyzed in the single two-element system. The full nested system is then analyzed in the presence of all possible defects on all twelve elements, whereby the magnitude of the defects is randomized within a given upper limit.

  9. Peculiarities of the Self-Action of Inclined Wave Beams Incident on a Discrete System of Optical Fibers (United States)

    Litvak, A. G.; Mironov, V. A.; Skobelev, S. A.; Smirnov, L. A.


    Based on a discrete nonlinear Schrödinger equation (DNSE), we studied analytically and numerically the peculiarities of the self-action of one-dimensional quasi-optic wave beams injected into a spatially inhomogeneous medium consisting of a set of equidistant mutually coupled optical fibers. A variational approach allowing the prediction of the global evolution of localized fields with the initially plane phase front was developed. The self-consistent equations are obtained for the main parameters of such beams (the position of the center of mass, the effective width, and linear and quadratic phase-front corrections) in the aberrationless approximation. The case of radiation incident on a periodic system of nonlinear optical fibers at an angle to the axis oriented along them is analyzed in detail. It is shown that for the radiation power exceeding a critical value, the self-focusing of the wave field is observed, which is accompanied by the shift of the intensity maximum followed by the concentration of the main part of radiation only in one of the structural elements of the array under study. In this case, the beams propagate along paths considerably different from linear and the direction of their propagation changes compared to the initial direction. Asymptotic expressions are found that allow us to estimate the self-focusing length and to determine quite accurately the final position of a point with the maximum field amplitude after radiation trapping a channel. The results of the qualitative study of the possible self-channeling regimes for wave beams in a system of weakly coupled optical fibers in the aberrationless approximation are compared with the results of direct numerical simulations within the DNSE framework.

  10. Coupled thermal-optic effects and electrical modulation mechanism of birefringence crystal with Gaussian laser incidence

    International Nuclear Information System (INIS)

    Zhou Ji; He Zhi-Hong; Ma Yu; Dong Shi-Kui


    We study the Gaussian laser transmission in lithium niobate crystal (LiNbO 3 ) by using the finite element method to solve the electromagnetic field’s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave’s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are considered. Influences of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer

  11. Incidence and prognostic factor of ethambutol-related optic neuropathy: 10-year experience in southern Taiwan

    Directory of Open Access Journals (Sweden)

    Shih-Chou Chen


    Full Text Available To investigate the incidence and prognostic factors of ethambutol-related optic neuropathy (EON in one medical center of southern Taiwan, a retrospective chart review study with 4803 newly diagnosed tuberculosis cases from January 2002 to July 2011 at one medical center hospital in southern Taiwan were reviewed. Of these patients, 1004 had ophthalmic records. Sixty-two cases (1.29% experienced visual impairment and were diagnosed as EON with mean visual acuity of 0.86 ± 0.69 by logMAR. Sixteen of the 62 patients had a follow-up time > 6 months. Of these, eight patients (50% showed visual improvement (an increase in visual acuity of ≥ 2 Snellen lines after ethambutol was discontinued. Another eight patients (50% showed no visual improvement. We analyzed multiple factors between the patients with and without visual improvement by logistic regression, including body weight, daily dose of ethambutol, duration of ethambutol use, cumulative dose of ethambutol, renal function, underlying disease of diabetes mellitus, hypertension, and initial visual acuity showed no statistically significant difference. In conclusion, the incidence of EON was 1.29%. Half of the patients showed visual improvement after discontinuation of ethambutol, and no obvious prognostic factors were found to facilitate the vision recovery. Ethambutol should be discontinued as soon as EON is suspected.

  12. Influence of gap and overlap paradigms on saccade latencies and vergence eye movements in seven-year-old children. (United States)

    Bucci, Maria Pia; Pouvreau, Nathalie; Yang, Qing; Kapoula, Zoï


    The latency of eye movements is influenced by the fixation task; when the fixation stimulus is switched off before the target presentation (gap paradigm) the latency becomes short and express movements occur. In contrast, when the fixation stimulus remains on when the target appears (overlap paradigm), eye movement latency is longer. Several previous studies have shown increased rates of express saccades in children; however the presence of an express type of latency for vergence and combined movements in children has never been explored. The present study examines the effects of the gap and the overlap paradigms on horizontal saccades at far (150 cm) and at close (20 cm) viewing distances, on vergence along the median plane, and on saccades combined with convergence or divergence in 15 normal seven-year-old children. The results show that the gap paradigm produced shorter latency for all eye movements than the overlap paradigm, but the difference was only significant for saccades at close viewing distances, for divergence (pure and combined), and for saccades combined with vergence. The gap paradigm produced significantly higher rates of express latencies for saccades at close viewing distances, for divergence, and for saccades combined with divergence; in contrast, the frequencies of express latencies for saccades at far viewing distances and for convergence (pure or combined) were similar in the gap and the overlap paradigms. Interestingly, the rate of anticipatory latencies (gap paradigm. Our collective findings suggest that the initiation of saccades at close viewing distances and of divergence is more reflexive, particularly in the gap paradigm. The finding of frequent anticipatory divergence that occurs at similar rates for seven-year-old children (this study) and for adults (Coubard et al., 2004, Exp Brain Res 154:368-381) indicates that predictive initiation of divergence is dominant.

  13. Centrality and Flow Vergence gradient based Path analysis of scientific literature: A case study of Biotechnology for Engineering (United States)

    Lathabai, Hiran H.; Prabhakaran, Thara; Changat, Manoj


    Biotechnology, ever since its inception has had a huge impact on the society and its various applications have been intricately woven into the human web of life. Its evolution amidst all the other research realms vital to mankind is remarkable. In this paper, we intend to identify the radical innovations in Biotechnology for Engineering using network analyses. Centrality analysis and Path analysis are used for identifying important works. Existence of Flow Vergence effect in the scientific literature is revealed. Flow Vergence gradient, an arc metric derived from FV model, is utilised for Path analysis which detects pivotal papers of paradigm shift more accurately. A major paradigm shift has been identified in the business models of Biotechnology for Engineering - 'Capability to Connectivity' model. Evidence towards the adoption of business practices in BT firms by nanotechnology start-ups is also identified. The notion of critical divergence is introduced and the exhibition of interdisciplinary interaction in emerging fields due to critical divergence is discussed. Implications of above analyses which target: (i) Science and technology policy makers, (ii) industrialists and investors, (iii) researchers in academia as well as industry, are also discussed.

  14. Mechanisms of Vertical Fusional Vergence in Patients With "Congenital Superior Oblique Paresis" Investigated With an Eye-Tracking Haploscope. (United States)

    Irsch, Kristina; Guyton, David L; Park, Hee-Jung S; Ying, Howard S


    To determine the mechanisms of vertical fusional vergence in patients with "congenital unilateral superior oblique paresis" (SOP) and to discuss the implications of these mechanisms. Eleven patients were examined with our eye-tracking haploscope. Three different fusion mechanisms were found, producing significantly different cyclovergence to vertical vergence ratios (P extorsion between the two eyes in straight-ahead gaze: The patient with oblique-muscle-mediated fusion showed essentially no subjective extorsion (0.5°), the patients with vertical-rectus-muscle-mediated vertical fusion showed a mean ± SD subjective extorsion of 3.6° ± 1.4°, and the patients with the mixed (oblique/rectus) fusion mechanism showed 7.0° ± 1.7° (P < 0.05). The choice of fusion mechanism may be a function of how much intorting effect is needed. Use of the oblique muscles bilaterally causes the least intorting effect, use of the vertical rectus muscles bilaterally adds more intorting effect, and activation of the "paretic" superior oblique muscle in the higher eye and the superior rectus muscle in the lower eye provides the greatest intorting effect. Subclassifying "congenital SOP" in this way (in which the "paretic" muscle may remain functional in many cases) may help guide its optimal surgical correction.

  15. Asymmetry of magneto-optical Kerr effect loops of Co nano-columns grown by oblique incident angle deposition

    International Nuclear Information System (INIS)

    Tang, F.; Liu, D.-L.; Ye, D.-X.; Lu, T.-M.; Wang, G.-C.


    Magneto-optical Kerr effect (MOKE) in the longitudinal mode was used to measure the in-plane magnetic anisotropy of about 300nm thick Co nano-column films that were grown by e-beam evaporation at different oblique incident angles (0-85 o ) on native SiO 2 substrates at room temperature. The symmetry of MOKE loops measured at azimuthal angles that are 180 o apart is obviously broken for Co nano-column films grown at high deposition angles >70 o . The plot of coercivity H c of loops versus azimuthal angle shows that H c values for azimuthal angles between -90 o and 90 o are much larger than the values for azimuthal angles between 90 o and 270 o . The asymmetry of coercivity is due to MOKE measurement that combines both longitudinal and polar Kerr effects. This combination is caused by the oblique magnetic anisotropy associated with the tilted Co nano-columns. A method is introduced to separate the longitudinal and polar Kerr effects. The longitudinal Kerr effect is obtained by adding hysteresis loops measured at azimuthal angles 180 o apart while the polar Kerr effect is obtained by subtracting these two loops. By comparing these two orthogonal magnetization components represented by longitudinal and polar Kerr effects, we show that magnetization rotation exists in the magnetic reversal process even at azimuthal angle φ=0 o that is the closest in-plane direction to the easy axis. After separating these two Kerr effects, the two-fold symmetry of coervicity associated with tilted nano-columns measured by longitudinal Kerr effect is restored

  16. A systematics of optical model compound nucleus formation cross sections for neutrons, proton, deuteron, 3He and alpha particle incidents

    International Nuclear Information System (INIS)

    Murata, Toru


    Simple formulae to reproduce the optical model compound nucleus formation cross sections for neutron, proton, deuteron, triton, 3 He and alpha particles are presented for target nuclei of light to medium weight mass region. (author)

  17. Optics

    CERN Document Server

    Mathieu, Jean Paul


    Optics, Parts 1 and 2 covers electromagnetic optics and quantum optics. The first part of the book examines the various of the important properties common to all electromagnetic radiation. This part also studies electromagnetic waves; electromagnetic optics of transparent isotropic and anisotropic media; diffraction; and two-wave and multi-wave interference. The polarization states of light, the velocity of light, and the special theory of relativity are also examined in this part. The second part is devoted to quantum optics, specifically discussing the classical molecular theory of optical p

  18. Optics

    CERN Document Server

    Fincham, W H A


    Optics: Ninth Edition Optics: Ninth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommen

  19. Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser. (United States)

    Krzywinski, Jacek; Conley, Raymond; Moeller, Stefan; Gwalt, Grzegorz; Siewert, Frank; Waberski, Christoph; Zeschke, Thomas; Cocco, Daniele


    The Linac Coherent Light Source is upgrading its machine to high repetition rate and to extended ranges. Novel coatings, with limited surface oxidation, which are able to work at the carbon edge, are required. In addition, high-resolution soft X-ray monochromators become necessary. One of the big challenges is to design the mirror geometry and the grating profile to have high reflectivity (or efficiency) and at the same time survive the high peak energy of the free-electron laser pulses. For these reasons the experimental damage threshold, at 900 eV, of two platinum-coated gratings with different blazed angles has been investigated. The gratings were tested at 1° grazing incidence. To validate a model for which the damage threshold on the blaze grating can be estimated by calculating the damage threshold of a mirror with an angle of incidence identical to the angle of incidence on the grating plus the blaze angle, tests on Pt-coated substrates have also been performed. The results confirmed the prediction. Uncoated silicon, platinum and SiB 3 (both deposited on a silicon substrate) were also investigated. In general, the measured damage threshold at grazing incidence is higher than that calculated under the assumption that there is no energy transport from the volume where the photons are absorbed. However, it was found that, for the case of the SiB 3 coating, the grazing incidence condition did not increase the damage threshold, indicating that the energy transport away from the extinction volume is negligible.

  20. Optics

    CERN Document Server

    Fincham, W H A


    Optics: Eighth Edition covers the work necessary for the specialization in such subjects as ophthalmic optics, optical instruments and lens design. The text includes topics such as the propagation and behavior of light; reflection and refraction - their laws and how different media affect them; lenses - thick and thin, cylindrical and subcylindrical; photometry; dispersion and color; interference; and polarization. Also included are topics such as diffraction and holography; the limitation of beams in optical systems and its effects; and lens systems. The book is recommended for engineering st

  1. Inspection of 56Fe γ-Ray angular distributions as a function of incident neutron energy using optical model approaches

    Directory of Open Access Journals (Sweden)

    Vanhoy J.R.


    Full Text Available Neutron inelastic scattering cross sections measured directly through (n,n or deduced from γ-ray production cross sections following inelastic neutron scattering (n,n′γ are a focus of basic and applied research at the University of Kentucky Accelerator Laboratory ( For nuclear data applications, angle-integrated cross sections are desired over a wide range of fast neutron energies. Several days of experimental beam time are required for a data set at each incident neutron energy, which limits the number of angular distributions that can be measured in a reasonable amount of time. Approximations can be employed to generate cross sections with a higher energy resolution, since at 125o, the a2P2 term of the Legendre expansion is identically zero and the a4P4 is assumed to be very small. Provided this assumption is true, a single measurement at 125o would produce the γ-ray production cross section. This project tests these assumptions and energy dependences using the codes CINDY/SCAT and TALYS/ECIS06/SCAT. It is found that care must be taken when interpreting γ-ray excitation functions as cross sections when the incident neutron energy is < 1000 keV above threshold or before the onset of feeding.

  2. Inspection of 56Fe γ-Ray angular distributions as a function of incident neutron energy using optical model approaches (United States)

    Vanhoy, J. R.; Ramirez, A. P.; Alcorn-Dominguez, D. K.; Hicks, S. F.; Peters, E. E.; McEllistrem, M. T.; Mukhopadhyay, S.; Yates, S. W.


    Neutron inelastic scattering cross sections measured directly through (n,n) or deduced from γ-ray production cross sections following inelastic neutron scattering (n,n'γ) are a focus of basic and applied research at the University of Kentucky Accelerator Laboratory ( For nuclear data applications, angle-integrated cross sections are desired over a wide range of fast neutron energies. Several days of experimental beam time are required for a data set at each incident neutron energy, which limits the number of angular distributions that can be measured in a reasonable amount of time. Approximations can be employed to generate cross sections with a higher energy resolution, since at 125o, the a2P2 term of the Legendre expansion is identically zero and the a4P4 is assumed to be very small. Provided this assumption is true, a single measurement at 125o would produce the γ-ray production cross section. This project tests these assumptions and energy dependences using the codes CINDY/SCAT and TALYS/ECIS06/SCAT. It is found that care must be taken when interpreting γ-ray excitation functions as cross sections when the incident neutron energy is < 1000 keV above threshold or before the onset of feeding.

  3. Analysis of mesoporous thin films by X-ray reflectivity, optical reflectivity and grazing incidence small angle X-ray scattering

    International Nuclear Information System (INIS)

    Gibaud, A.; Dourdain, S.; Vignaud, G.


    It is well-established that X-ray reflectivity (XR) is an invaluable tool to investigate the structure of thin films. Indeed, this technique provides under correct analysis, the electron density profile of thin films in the direction perpendicular to the substrate. For thin films that exhibit lateral ordering at the nanometer scale, grazing incidence small angle X-ray scattering (GISAXS) ideally complements the XR technique to measure the scattering in off-specular directions. As typical examples, XR and GISAXS data of mesoporous silica thin films and porous materials are presented. The analysis of the XR curve allows to determine the porosity of the film. We also show that the combination of X-ray and visible optical reflection provides information about the index of refraction of thin films. Finally we report how capillary condensation of water can be monitored by XR and GISAXS

  4. Hot slumping glass technology for the grazing incidence optics of future missions with particular reference to IXO (United States)

    Ghigo, M.; Basso, S.; Bavdaz, M.; Conconi, P.; Citterio, O.; Civitani, M.; Friedrich, P.; Gallieni, D.; Guldimann, B.; Martelli, F.; Negri, R.; Pagano, G.; Pareschi, G.; Parodi, G.; Proserpio, L.; Salmaso, B.; Scaglione, F.; Spiga, D.; Tagliaferri, G.; Terzi, L.; Tintori, M.; Vongehr, M.; Wille, E.; Winter, A.; Zambra, A.


    The mirrors of the International X-ray Observatory (IXO) consist of a large number of high quality segments delivering a spatial resolution better than 5 arcsec. A study concerning the slumping of thin glass foils for the IXO mirrors is under development in Europe, funded by ESA and led by the Brera Observatory. We are investigating two approaches, the "Direct" and "Indirect" slumping technologies, being respectively based on the use of convex and concave moulds. In the first case during the thermal cycle the optical surface of the glass is in direct contact with the mould surface, while in the second case it is the rear side of the foil which touches the master. Both approaches present pros and cons and aim of this study is also to make an assessment of both processes and to perform a trade-off between the two. The thin plates are made of D263glass produced by Schott. Each plate is 0.4 mm thick, with a reflecting area of 200 mm x 200 mm; the mould are made of Fused Silica. After the thermal cycle the slumped MPs are characterized to define their optical quality and microroughness. The adopted integration process foresees the bonding of the slumped foils to a rigid backplane by means of reinforcing ribs. During the bonding process the plates are constrained to stay in close contact to the surface of the master (i.e. the same mould used for the hot slumping process) by the application of a vacuum pump suction. In this way spring-back deformations and low frequency errors still present on the foil profile after slumping can be corrected. In this paper we present the preliminary results concerning achieved during the first part of the project.

  5. Constellation-X to Generation-X: evolution of large collecting area moderate resolution grazing incidence x-ray telescopes to larger area high-resolution adjustable optics (United States)

    Reid, Paul B.; Cameron, Robert A.; Cohen, Lester; Elvis, Martin; Gorenstein, Paul; Jerius, Diab; Petre, Robert; Podgorski, William A.; Schwartz, Daniel A.; Zhang, William W.


    Large collecting area x-ray telescopes are designed to study the early Universe, trace the evolution of black holes, stars and galaxies, study the chemical evolution of the Universe, and study matter in extreme environments. The Constellation-X mission (Con-X), planned for launch in 2016, will provide ~ 10^4 cm^2 collecting area with 15 arc-sec resolution, with a goal of 5 arc-sec. Future missions require larger collecting area and finer resolution. Generation-X (Gen-X), a NASA Visions Mission, will achieve 100 m^2 effective area at 1 keV and angular resolution of 0.1 arc-sec, half power diameter. We briefly describe the Con-X flowdown of imaging requirements to reflector figure error. To meet requirements beyond Con-X, Gen-X optics will be thinner and more accurately shaped than has ever been accomplished. To meet these challenging goals, we incorporate for the first time active figure control with grazing incidence optics. Piezoelectric material will be deposited in discrete cells directly on the back surface of the optical segments, with the strain directions oriented parallel to the surface. Differential strain between the two layers of the mirror causes localized bending in two directions, enabling local figure control. Adjusting figure on-orbit eases fabrication and metrology. The ability to make changes to mirror figure adds margin by mitigating risk due to launch-induced deformations and/or on-orbit degradation. We flowdown the Gen-X requirements to mirror figure and four telescope designs, and discuss various trades between the designs.

  6. Mechanisms of Vertical Fusional Vergence in Patients With “Congenital Superior Oblique Paresis” Investigated With an Eye-Tracking Haploscope (United States)

    Irsch, Kristina; Guyton, David L.; Park, Hee-Jung S.; Ying, Howard S.


    Purpose To determine the mechanisms of vertical fusional vergence in patients with “congenital unilateral superior oblique paresis” (SOP) and to discuss the implications of these mechanisms. Methods Eleven patients were examined with our eye-tracking haploscope. Results Three different fusion mechanisms were found, producing significantly different cyclovergence to vertical vergence ratios (P extorsion between the two eyes in straight-ahead gaze: The patient with oblique-muscle–mediated fusion showed essentially no subjective extorsion (0.5°), the patients with vertical-rectus-muscle–mediated vertical fusion showed a mean ± SD subjective extorsion of 3.6° ± 1.4°, and the patients with the mixed (oblique/rectus) fusion mechanism showed 7.0° ± 1.7° (P < 0.05). Conclusions The choice of fusion mechanism may be a function of how much intorting effect is needed. Use of the oblique muscles bilaterally causes the least intorting effect, use of the vertical rectus muscles bilaterally adds more intorting effect, and activation of the “paretic” superior oblique muscle in the higher eye and the superior rectus muscle in the lower eye provides the greatest intorting effect. Subclassifying “congenital SOP” in this way (in which the “paretic” muscle may remain functional in many cases) may help guide its optimal surgical correction. PMID:26275134

  7. Visual optics under the wavefront perspective

    Directory of Open Access Journals (Sweden)

    Sidney Júlio Faria-E-Sousa


    Full Text Available Some intriguing concepts of visual optics cannot be explained by ray tracing. However, they can be clarified using wavefront formalism. Its main advantage is in the use of the concept of vergence, which is very helpful in interpreting the optical phenomena involved in the neutralization of the ametropias. In this line of thinking, the major role of a lens is in the creation of a new light source (the image point that orientates the refracted waves. Once the nature and position of this source is known, one can easily predict the behavior of the wavefronts. The formalism also allows for an easier understanding on how wavefronts relate to light rays and on how algebraic signs are assigned to optical distances.

  8. Low Group Delay Dispersion Optical Coating for Broad Bandwidth High Reflection at 45° Incidence, P Polarization of Femtosecond Pulses with 900 nm Center Wavelength

    Directory of Open Access Journals (Sweden)

    John C. Bellum


    Full Text Available We describe an optical coating design suitable for broad bandwidth high reflection (BBHR at 45° angle of incidence (AOI, P polarization (Ppol of femtosecond (fs laser pulses whose wavelengths range from 800 to 1000 nm. Our design process is guided by quarter-wave HR coating properties. The design must afford low group delay dispersion (GDD for reflected light over the broad, 200 nm bandwidth in order to minimize temporal broadening of the fs pulses due to dispersive alteration of relative phases between their frequency components. The design should also be favorable to high laser-induced damage threshold (LIDT. We base the coating on TiO2/SiO2 layer pairs produced by means of e-beam evaporation with ion-assisted deposition, and use OptiLayer Thin Film Software to explore designs starting with TiO2/SiO2 layers having thicknesses in a reverse chirped arrangement. This approach led to a design with R > 99% from 800 to 1000 nm and GDD < 20 fs2 from 843 to 949 nm (45° AOI, Ppol. The design’s GDD behaves in a smooth way, suitable for GDD compensation techniques, and its electric field intensities show promise for high LIDTs. Reflectivity and GDD measurements for the initial test coating indicate good performance of the BBHR design. Subsequent coating runs with improved process calibration produced two coatings whose HR bands satisfactorily meet the design goals. For the sake of completeness, we summarize our previously reported transmission spectra and LIDT test results with 800 ps, 8 ps and 675 fs pulses for these two coatings, and present a table of the LIDT results we have for all of our TiO2/SiO2 BBHR coatings, showing the trends with test laser pulse duration from the ns to sub-ps regimes.

  9. Optical mapping near-eye three-dimensional display with correct focus cues (United States)

    Cui, Wei; Gao, Liang


    We present an optical mapping near-eye (OMNI) three-dimensional display method for wearable devices. By dividing a display screen into different sub-panels and optically mapping them to various depths, we create a multiplane volumetric image with correct focus cues for depth perception. The resultant system can drive the eye's accommodation to the distance that is consistent with binocular stereopsis, thereby alleviating the vergence-accommodation conflict, the primary cause for eye fatigue and discomfort. Compared with the previous methods, the OMNI display offers prominent advantages in adaptability, image dynamic range, and refresh rate.

  10. Grazing Incidence X-Ray Fluorescence of periodic structures – a comparison between X-ray Standing Waves and Geometrical Optics calculations.


    Reinhardt Falk; Nowak Stanislaw H.; Beckhoff Burkhard; Dousse Jean-Claude; Schoengen Max


    Grazing incidence X-ray fluorescence spectra of nano-scaled periodic line structures were recorded at the four crystal monochromator beamline in the laboratory of the Physikalisch-Technische Bundesanstalt at the synchrotron radiation facility BESSY II. For different tilt angles between the lines and the plane of incidence of the monochromatic synchrotron radiation, spectral features are observed which can be understood and explained with calculations of the emerging X-ray standing wave (XSW) ...

  11. Wheelchair incidents

    NARCIS (Netherlands)

    Drongelen AW van; Roszek B; Hilbers-Modderman ESM; Kallewaard M; Wassenaar C; LGM


    This RIVM study was performed to gain insight into wheelchair-related incidents with powered and manual wheelchairs reported to the USA FDA, the British MDA and the Dutch Center for Quality and Usability Research of Technical Aids (KBOH). The data in the databases do not indicate that incidents with

  12. Reflective optics

    CERN Document Server

    Korsch, Dietrich


    This is the first book dedicated exclusively to all-reflective imaging systems. It is a teaching tool as well as a practical design tool for anyone who specializes in optics, particularly for those interested in telescopes, infrared, and grazing-incidence systems. The first part of the book describes a unified geometric optical theory of all-reflective imaging systems (from near-normal to grazing incidence) developed from basic principles. The second part discusses correction methods and a multitude of closed-form solutions of well-corrected systems, supplemented with many conventional and unc

  13. Incidents analysis

    International Nuclear Information System (INIS)

    Francois, P.


    We undertook a study programme at the end of 1991. To start with, we performed some exploratory studies aimed at learning some preliminary lessons on this type of analysis: Assessment of the interest of probabilistic incident analysis; possibility of using PSA scenarios; skills and resources required. At the same time, EPN created a working group whose assignment was to define a new approach for analysis of incidents on NPPs. This working group gave thought to both aspects of Operating Feedback that EPN wished to improve: Analysis of significant incidents; analysis of potential consequences. We took part in the work of this group, and for the second aspects, we proposed a method based on an adaptation of the event-tree method in order to establish a link between existing PSA models and actual incidents. Since PSA provides an exhaustive database of accident scenarios applicable to the two most common types of units in France, they are obviously of interest for this sort of analysis. With this method we performed some incident analyses, and at the same time explores some methods employed abroad, particularly ASP (Accident Sequence Precursor, a method used by the NRC). Early in 1994 EDF began a systematic analysis programme. The first, transient phase will set up methods and an organizational structure. 7 figs

  14. Grazing incidence beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Akkapeddi, P.R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V.K.


    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  15. Optics/Optical Diagnostics Laboratory (United States)

    Federal Laboratory Consortium — The Optics/Optical Diagnostics Laboratory supports graduate instruction in optics, optical and laser diagnostics and electro-optics. The optics laboratory provides...

  16. Surface optical vortices (United States)

    Lembessis, V. E.; Babiker, M.; Andrews, D. L.


    It is shown how the total internal reflection of orbital-angular-momentum-endowed light can lead to the generation of evanescent light possessing rotational properties in which the intensity distribution is firmly localized in the vicinity of the surface. The characteristics of these surface optical vortices depend on the form of the incident light and on the dielectric mismatch of the two media. The interference of surface optical vortices is shown to give rise to interesting phenomena, including pattern rotation akin to a surface optical Ferris wheel. Applications are envisaged to be in atom lithography, optical surface tweezers, and spanners.

  17. MCFRS Incidents by Station (United States)

    Montgomery County of Maryland — This dataset contains the monthly summary data indicating incident occurred in each fire station response area. The summary data is the incident count broken down by...

  18. Police Incident Reports Written (United States)

    Town of Chapel Hill, North Carolina — This table contains incident reports filed with the Chapel Hill Police Department. Multiple incidents may have been reported at the same time. The most serious...

  19. Optic neuritis (United States)

    Retro-bulbar neuritis; Multiple sclerosis - optic neuritis; Optic nerve - optic neuritis ... The exact cause of optic neuritis is unknown. The optic nerve carries visual information from your eye to the brain. The nerve can swell when ...

  20. Incident Information Management Tool

    CERN Document Server

    Pejovic, Vladimir


    Flaws of\tcurrent incident information management at CMS and CERN\tare discussed. A new data\tmodel for future incident database is\tproposed and briefly described. Recently developed draft version of GIS-­‐based tool for incident tracking is presented.

  1. Surface optical vortices


    Lembessis, V. E.; Babiker, M.; Andrews, D L.


    It is shown how the total internal reflection of orbital-angular-momentum-endowed light can lead to the generation of evanescent light possessing rotational properties in which the intensity distribution is firmly localized in the vicinity of the surface. The characteristics of these surface optical vortices depend on the form of the incident light and on the dielectric mismatch of the two media. The interference of surface optical vortices is shown to give rise to interesting phenomena, incl...

  2. Progress report on research project 'Coupled-channels optical model potentials for calculations with coupling built on soft-rotator model for nucleon induced reactions up to 200 MeV incident energies in A =24-120 mass region'

    International Nuclear Information System (INIS)

    Soukhovitski, E.


    Full text: During these nine months the Research Contract activity was developing according to the schedule as fixed in the Contract. Developing a global optical potential for even-even nuclides with A = 24-120 mass for coupled-channels optical model calculations based on coupling built on soft-rotator nuclear model Hamiltonian wave functions we already: 1. Determined Nuclear Hamiltonian parameters describing low-lying collective levels of even-even nuclides with A = 24-120 mass for all nuclides having experimental optical data available. 2. Formatted all the available optical experimental data for even-even nuclides with A = 24-120 mass into input of OPTMAN code for optical potential search option. Data still unavailable in the EXFOR database was submitted to the Nuclear Data Section for inclusion. 3. Derived a local OMP parameters for even-even A = 24-120 mass nuclides. 4. Release the OPTMAN code's user guide with the support of our Japanese collaborators. The User guide was published as JAERI technical report as cited below: E.Sh. Soukhovitskii, S. Chiba, O. Iwamoto, K. Shibata, T. Fukahori, G.B. Morogovskij (JAERI technical report 'Programs OPTMAN and SHEMMAN Version 8 (2004)', JAERI/Data-Code 2005-002, 2005). It is freely available on request from Japanese Nuclear Data Center. Global optical potential for even-even nuclides with A=24-120 mass, which is the main goal of the Contract's first year activity, will be derived based on individual optical potential parameters already determined. This research contract made possible very fruitful international scientific cooperation aimed to incorporate ideas on dispersive relationships between imaginary and real parts of optical potential developed earlier by Roberto Capote (IAEA/NDS) and Jose Manuel Quesada (Seville University) in the CC optical code OPTMAN. The real possibility to use a modified OPTMAN code for high priority practical applications arises. These activities are coordinated through RIPL CRP. We

  3. Fiber optic hydrophone (United States)

    Kuzmenko, P.J.; Davis, D.T.


    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer is disclosed. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optical fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends. 2 figures.

  4. Fiber optic hydrophone (United States)

    Kuzmenko, Paul J.; Davis, Donald T.


    A miniature fiber optic hydrophone based on the principles of a Fabry-Perot interferometer. The hydrophone, in one embodiment, includes a body having a shaped flexible bladder at one end which defines a volume containing air or suitable gas, and including a membrane disposed adjacent a vent. An optic fiber extends into the body with one end terminating in spaced relation to the membrane. Acoustic waves in the water that impinge on the bladder cause the pressure of the volume therein to vary causing the membrane to deflect and modulate the reflectivity of the Fabry-Perot cavity formed by the membrane surface and the cleaved end of the optical fiber disposed adjacent to the membrane. When the light is transmitted down the optical fiber, the reflected signal is amplitude modulated by the incident acoustic wave. Another embodiment utilizes a fluid filled volume within which the fiber optic extends.

  5. Optical transmissivity of metallic nanowires (United States)

    Nairat, Mazen S.


    Optical transmissivity and reflectivity of one dimensional array of metallic nanowires embedded in transparent dielectric is characterized. i employ wave optics simulation to analyze the optical field distribution in both the dielectric and the nanowires. The results indicate that the transmissivity and reflectivity depend on the polarization states of the incident light. The metallic nanowires matrix transmit in-plane polarization but block light out at of-plane polarization.

  6. Acute incidents during anaesthesia

    African Journals Online (AJOL)

    Incidents can occur during induction, maintenance and emergence from anaesthesia. The following acute critical incidents are discussed in this article: • Anaphylaxis. • Aspiration ..... Already used in South Africa and Malawi, a scale-up of the technique is under way in Tanzania, Rwanda and Ghana. The report found that.

  7. Radiological incidents in radiotherapy

    International Nuclear Information System (INIS)

    Hobzova, L.; Novotny, J.


    In many countries a reporting system of radiological incidents to national regulatory body exists and providers of radiotherapy treatment are obliged to report all major and/or in some countries all incidents occurring in institution. State Office for Nuclear Safety (SONS) is providing a systematic guidance for radiotherapy departments from 1997 by requiring inclusion of radiation safety problems into Quality assurance manual, which is the basic document for obtaining a license of SONS for handling with sources of ionizing radiation. For that purpose SONS also issued the recommendation 'Introduction of QA system for important sources in radiotherapy-radiological incidents' in which the radiological incidents are defined and the basic guidance for their classification (category A, B, C, D), investigation and reporting are given. At regular periods the SONS in co-operation with radiotherapy centers is making a survey of all radiological incidents occurring in institutions and it is presenting obtained information in synoptic communication (2003 Motolske dny, 2005 Novy Jicin). This presentation is another summary report of radiological incidents that occurred in our radiotherapy institutions during last 3 years. Emphasis is given not only to survey and statistics, but also to analysis of reasons of the radiological incidents and to their detection and prevention. Analyses of incidents in radiotherapy have led to a much broader understanding of incident causation. Information about the error should be shared as early as possible during or after investigation by all radiotherapy centers. Learning from incidents, errors and near misses should be a part of improvement of the QA system in institutions. Generally, it is recommended that all radiotherapy facilities should participate in the reporting, analyzing and learning system to facilitate the dissemination of knowledge throughout the whole country to prevent errors in radiotherapy.(authors)

  8. UltraForm Finisher Optical Mandrel Fabrication, Phase I (United States)

    National Aeronautics and Space Administration — The requirements for cost effective manufacturing and metrology of normal incidence and grazing incidence X-Ray optical surfaces is instrumental for the success of...

  9. Radiative properties of optical board embedded with optical black holes

    International Nuclear Information System (INIS)

    Qiu, J.; Liu, L.H.; Hsu, P.-F.


    Unique radiative properties, such as wavelength-selective transmission or absorption, have been intensively studied. Historically, geometries for wavelength-selective of light absorption were developed based on metallic periodical structures, which were only applied in the case of TM wave incidence due to the excitation of surface plasmons. In this paper, we develop an alternative approach to selective wavelength of light absorption (both TE and TM waves), based on an optical board periodical embedded with optical black holes. Numerical work was carried out to study such structure's radiative properties within the wavelength range of 1-100 μm. The electromagnetic wave transmission through such a structure is predicted by solving Maxwell's equations using the finite-difference time-domain (FDTD) method. Spectral absorptance varies with the period of optical black holes. When the incidence wavelength is much larger than the inner core radius, most of the light energy will be transmitted through the inner core. Otherwise, the energy will be mainly absorbed. Numerical results of the radiative properties of the optical board with different incidence wavelengths are also obtained. The effect of the oblique incidence wave is investigated. This study helps us gain a better understanding of the radiative properties of an optical board embedded with optical black holes and develop an alternative approach to selective light absorption.

  10. Critical incident stress management. (United States)

    Lim, J J; Childs, J; Gonsalves, K


    Recent studies have indicated implementation of the CISM Program has impacted and reduced the cost of workers' compensation claims for stress related conditions and the number of lost work days (Ott, 1997; Western Management Consultants, 1996). Occupational health professionals need to be ready to develop and implement a comprehensive critical incident stress management process in anticipation of a major event. The ability to organize, lead, or administer critical incident stress debriefings for affected employees is a key role for the occupational health professional. Familiarity with these concepts and the ability to identify a critical incident enhances value to the business by mitigating the stress and impact to the workplace. Critical Incident Stress Management Systems have the potential for decreasing stress and restoring employees to normal life function--a win/win situation for both the employees and the organization.

  11. Marine Animal Incident Database (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Large whale stranding, death, ship strike and entanglement incidents are all recorded to monitor the health of each population and track anthropogenic factors that...

  12. Police Incident Blotter (Archive) (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The Police Blotter Archive contains crime incident data after it has been validated and processed to meet Uniform Crime Reporting (UCR) standards, published on a...

  13. Prediction of Safety Incidents (United States)

    National Aeronautics and Space Administration — Safety incidents, including injuries, property damage and mission failures, cost NASA and contractors thousands of dollars in direct and indirect costs. This project...

  14. 2011 Japanese Nuclear Incident (United States)

    EPA’s RadNet system monitored the environmental radiation levels in the United States and parts of the Pacific following the Japanese Nuclear Incident. Learn about EPA’s response and view historical laboratory data and news releases.

  15. Information Security Incident Management

    Directory of Open Access Journals (Sweden)

    D. I. Persanov


    Full Text Available The present report highlights the points of information security incident management in an enterprise. Some aspects of the incident and event classification are given. The author presents his view of the process scheme over the monitoring and processing information security events. Also, the report determines a few critical points of the listed process and gives the practical recommendations over its development and optimization.

  16. Figure and finish of grazing incidence mirrors

    International Nuclear Information System (INIS)

    Takacs, P.Z.; Church, E.L.


    Great improvement has been made in the past several years in the quality of optical components used in synchrotron radiation (SR) beamlines. Most of this progress has been the result of vastly improved metrology techniques and instrumentation permitting rapid and accurate measurement of the surface finish and figure on grazing incidence optics. A significant theoretical effort has linked the actual performance of components used as x-ray wavelengths to their topological properties as measured by surface profiling instruments. Next-generation advanced light sources will require optical components and systems to have sub-arc second surface figure tolerances. This paper will explore the consequences of these requirements in terms of manufacturing tolerances to see if the present manufacturing state-of-the-art is capable of producing the required surfaces. 15 refs., 14 figs., 2 tabs

  17. Solid state optical microscope (United States)

    Young, Ian T.


    A solid state optical microscope wherein wide-field and high-resolution images of an object are produced at a rapid rate by utilizing conventional optics with a charge-coupled photodiode array. A galvanometer scanning mirror, for scanning in one of two orthogonal directions is provided, while the charge-coupled photodiode array scans in the other orthogonal direction. Illumination light from the object is incident upon the photodiodes, creating packets of electrons (signals) which are representative of the illuminated object. The signals are then processed, stored in a memory, and finally displayed as a video signal.

  18. Microstructured Optical Fibres

    DEFF Research Database (Denmark)


    complete PBGs, which reflects light incident from air or vacuum. Such structures may be used as cladding structures in optical fibres, where light is confined and thereby guided in a hollow core region. In addition, the present invention relates to designs for ultra low-loss PBG waveguiding structures......The present invention relates to a new class of optical waveguides, in which waveguiding along one or more core regions is obtained through the application of the Photonic Bandgap (PBG) effect. The invention further relates to optimised two-dimensional lattice structures capable of providing...

  19. Quantum optics

    National Research Council Canada - National Science Library

    Agarwal, G. S


    .... Focusing on applications of quantum optics, the textbook covers recent developments such as engineering of quantum states, quantum optics on a chip, nano-mechanical mirrors, quantum entanglement...

  20. Radiation incidents in dentistry

    International Nuclear Information System (INIS)

    Lovelock, D.J.


    Most dental practitioners act as their own radiographer and radiologist, unlike their medical colleagues. Virtually all dental surgeons have a dental X-ray machine for intraoral radiography available to them and 40% of dental practices have equipment for dental panoramic tomography. Because of the low energy of X-ray equipment used in dentistry, radiation incidents tend to be less serious than those associated with other aspects of patient care. Details of 47 known incidents are given. The advent of the 1985 and 1988 Ionising Radiation Regulations has made dental surgeons more aware of the hazards of radiation. These regulations, and general health and safety legislation, have led to a few dental surgeons facing legal action. Because of the publicity associated with these court cases, it is expected that there will be a decrease in radiation incidents arising from the practice of dentistry. (author)

  1. Optical RF Spectrum Analyzer (United States)

    trapping (ET) material of a spatial light modulator (SLM). A second optical subsystem directs coherent blue light generated by an argon laser to...resulting in the emissions of incoherent visible light. The incident coherent blue light is selectively absorbed at these exposed locations as it acts...filter. The coherent blue light which passes through the ET-SLM is Fourier transformed by a Fourier lens, and then detected by a CCD detector.

  2. High-power optics lasers and applications

    CERN Document Server

    Apollonov, Victor V


    This book covers the basics, realization and materials for high power laser systems and high power radiation interaction with  matter. The physical and technical fundamentals of high intensity laser optics and adaptive optics and the related physical processes in high intensity laser systems are explained. A main question discussed is: What is power optics? In what way is it different from ordinary optics widely used in cameras, motion-picture projectors, i.e., for everyday use? An undesirable consequence of the thermal deformation of optical elements and surfaces was discovered during studies of the interaction with powerful incident laser radiation. The requirements to the fabrication, performance and quality of optical elements employed within systems for most practical applications are also covered. The high-power laser performance is generally governed by the following: (i) the absorption of incident optical radiation (governed primarily by various absorption mechanisms), (ii) followed by a temperature ...

  3. Astronomical optics and elasticity theory

    CERN Document Server

    Lemaitre, Gerard Rene


    Astronomical Optics and Elasticity Theory provides a very thorough and comprehensive account of what is known in this field. After an extensive introduction to optics and elasticity, the book discusses variable curvature and multimode deformable mirrors, as well as, in depth, active optics, its theory and applications. Further, optical design utilizing the Schmidt concept and various types of Schmidt correctors, as well as the elasticity theory of thin plates and shells are elaborated upon. Several active optics methods are developed for obtaining aberration corrected diffraction gratings. Further, a weakly conical shell theory of elasticity is elaborated for the aspherization of grazing incidence telescope mirrors. The very didactic and fairly easy-to-read presentation of the topic will enable PhD students and young researchers to actively participate in challenging astronomical optics and instrumentation projects.

  4. Optical Computing

    Indian Academy of Sciences (India)

    Optics has been used in computing for a number of years but the main emphasis has been and continues to be to link portions of computers, for communications, or more intrin- sically in devices that have some optical application or component (optical pattern recognition, etc). Optical digi- tal computers are still some years ...

  5. Incidents in nuclear installations

    International Nuclear Information System (INIS)

    Franzen, L.F.; Wienhold, W.


    With reference to the incident list of the Ministry for the period 1971-74, Prof. Bechert has expressed a lot of questions and statements in a letter to the Government. The letter is quoted in full. Inadequate conclusions drawn by Prof. Bechert in connection with quotations from daily newspapers and other documents are put right. (HP) [de

  6. Lightning incidents in Mongolia

    Directory of Open Access Journals (Sweden)

    Myagmar Doljinsuren


    Full Text Available This is one of the first studies that has been conducted in Mongolia on the distribution of lightning incidents. The study covers a 10-year period from 2004 to 2013. The country records a human death rate of 15.4 deaths per 10 million people per year, which is much higher than that of many countries with similar isokeraunic level. The reason may be the low-grown vegetation observed in most rural areas of Mongolia, a surface topography, typical to steppe climate. We suggest modifications to Gomes–Kadir equation for such countries, as it predicts a much lower annual death rate for Mongolia. The lightning incidents spread over the period from May to August with the peak of the number of incidents occurring in July. The worst lightning affected region in the country is the central part. Compared with impacts of other convective disasters such as squalls, thunderstorms and hail, lightning stands as the second highest in the number of incidents, human deaths and animal deaths. Economic losses due to lightning is only about 1% of the total losses due to the four extreme weather phenomena. However, unless precautionary measures are not promoted among the public, this figure of losses may significantly increase with time as the country is undergoing rapid industrialization at present.

  7. Fire Incident Reporting Manual (United States)


    the result of an incident that requires (or should require) treatment by a practitioner of medicine , a registered emergency medical technician, or a...UNANNOUNCED AIRCRAFT EMERGENCYS ~~PRIOR TO TAKE OFF OR AFTERLADN 5 FUEL OPERATIONS REQUIRING 1AREING G A FIRE10 ARRESTING GEAR’BARRIER FR . ENGAGEMENTS AND

  8. Mie scattering eigenmodes for optical trapping


    Mazilu, Michael


    The Mie scattering theory enables the exact determination of the scattered field as a function of the incident field. Here, we use this approach to calculate the Hermitian relationship between the incident field and the optical forces acting on the scattering objects. This Hermitian relationship defines also a set of orthogonal optical eigenmodes which deliver a natural basis to describe momentum transfer in light-matter interactions. Publisher PDF Non peer reviewed

  9. Engineering Optics

    CERN Document Server

    Iizuka, Keigo


    Engineering Optics is a book for students who want to apply their knowledge of optics to engineering problems, as well as for engineering students who want to acquire the basic principles of optics. It covers such important topics as optical signal processing, holography, tomography, holographic radars, fiber optical communication, electro- and acousto-optic devices, and integrated optics (including optical bistability). As a basis for understanding these topics, the first few chapters give easy-to-follow explanations of diffraction theory, Fourier transforms, and geometrical optics. Practical examples, such as the video disk, the Fresnel zone plate, and many more, appear throughout the text, together with numerous solved exercises. There is an entirely new section in this updated edition on 3-D imaging.

  10. Constipation and Incident CKD. (United States)

    Sumida, Keiichi; Molnar, Miklos Z; Potukuchi, Praveen K; Thomas, Fridtjof; Lu, Jun Ling; Matsushita, Kunihiro; Yamagata, Kunihiro; Kalantar-Zadeh, Kamyar; Kovesdy, Csaba P


    Constipation is one of the most prevalent conditions in primary care settings and increases the risk of cardiovascular disease, potentially through processes mediated by altered gut microbiota. However, little is known about the association of constipation with CKD. In a nationwide cohort of 3,504,732 United States veterans with an eGFR ≥60 ml/min per 1.73 m 2 , we examined the association of constipation status and severity (absent, mild, or moderate/severe), defined using diagnostic codes and laxative use, with incident CKD, incident ESRD, and change in eGFR in Cox models (for time-to-event analyses) and multinomial logistic regression models (for change in eGFR). Among patients, the mean (SD) age was 60.0 (14.1) years old; 93.2% of patients were men, and 24.7% were diabetic. After multivariable adjustments, compared with patients without constipation, patients with constipation had higher incidence rates of CKD (hazard ratio, 1.13; 95% confidence interval [95% CI], 1.11 to 1.14) and ESRD (hazard ratio, 1.09; 95% CI, 1.01 to 1.18) and faster eGFR decline (multinomial odds ratios for eGFR slope constipation associated with an incrementally higher risk for each renal outcome. In conclusion, constipation status and severity associate with higher risk of incident CKD and ESRD and with progressive eGFR decline, independent of known risk factors. Further studies should elucidate the underlying mechanisms. Copyright © 2017 by the American Society of Nephrology.

  11. Cancer incidence among firefighters

    DEFF Research Database (Denmark)

    Pukkala, Eero; Martinsen, Jan Ivar; Weiderpass, Elisabete


    .51), adenocarcinoma of the lung (SIR=1.90, 95% CI 1.34 to 2.62), and mesothelioma (SIR=2.59, 95% CI 1.24 to 4.77). By contrast with earlier studies, the incidence of testicular cancer was decreased (SIR=0.51, 95% CI 0.23 to 0.98). CONCLUSIONS: Some of these associations have been observed previously, and potential...

  12. Method and apparatus for bistable optical information storage for erasable optical disks (United States)

    Land, Cecil E.; McKinney, Ira D.


    A method and an optical device for bistable storage of optical information, together with reading and erasure of the optical information, using a photoactivated shift in a field dependent phase transition between a metastable or a bias-stabilized ferroelectric (FE) phase and a stable antiferroelectric (AFE) phase in an lead lanthanum zirconate titanate (PLZT). An optical disk contains the PLZT. Writing and erasing of optical information can be accomplished by a light beam normal to the disk. Reading of optical information can be accomplished by a light beam at an incidence angle of 15 to 60 degrees to the normal of the disk.

  13. Cancer incidence among waiters

    DEFF Research Database (Denmark)

    Reijula, Jere; Kjaerheim, Kristina; Lynge, Elsebeth


    AIMS: To study cancer risk patterns among waiters in the Nordic countries. METHODS: We identified a cohort of 16,134 male and 81,838 female waiters from Denmark, Finland, Iceland, Norway and Sweden. During the follow-up period from 1961 to 2005, we found that 19,388 incident cancer cases were...... diagnosed. Standardised incidence ratio (SIR) was defined as the observed number of cancer cases divided by the expected number, based on national age, time period and gender-specific cancer incidence rates in the general population. RESULTS: The SIR of all cancers in waiters, in the five countries combined......, was 1.46 (95% CI 1.41-1.51) in men and 1.09 (1.07-1.11) in women. In male waiters, the SIR decreased from 1.79 (1.63-1.96) in 1961-1975, to 1.33 (1.26-1.40) in 1991-2005, but remained stable among women. The SIR among male waiters was highest for cancers in the pharynx (6.11; 95% CI 5.02-7.37), oral...

  14. Contaminated Mexican steel incident

    International Nuclear Information System (INIS)


    This report documents the circumstances contributing to the inadvertent melting of cobalt 60 (Co-60) contaminated scrap metal in two Mexican steel foundries and the subsequent distribution of contaminated steel products into the United States. The report addresses mainly those actions taken by US Federal and state agencies to protect the US population from radiation risks associated with the incident. Mexico had much more serious radiation exposure and contamination problems to manage. The United States Government maintained a standing offer to provide technical and medical assistance to the Mexican Government. The report covers the tracing of the source to its origin, response actions to recover radioactive steel in the United States, and return of the contaminated materials to Mexico. The incident resulted in significant radiation exposures within Mexico, but no known significant exposure within the United States. Response to the incident required the combined efforts of the Nuclear Regulatory Commission (NRC), Department of Energy, Department of Transportation, Department of State, and US Customs Service (Department of Treasury) personnel at the Federal level and representatives of all 50 State Radiation Control Programs and, in some instances, local and county government personnel. The response also required a diplomatic interface with the Mexican Government and cooperation of numerous commercial establishments and members of the general public. The report describes the factual information associated with the event and may serve as information for subsequent recommendations and actions by the NRC. 8 figures

  15. Plasmas produced by incident laser in solids

    International Nuclear Information System (INIS)

    Oliveira Campos, D. de; Boeckelmann, H.K.


    The experimental arrangement for plasma production by incident laser in solids and a system of diagnostics are presented. The system of diagnostics allows: verify the plasma generation and expansion through the ultrahigh-speed photography; obtain measurements of temperature and density by spectroscopy (using an optical analyser of multichannels) and obtain measurements of kinetic energy of ions through his fly time, using a 'Faraday cup'. A vacuum system with an adsorption pump for pre-vacuum and ionic pump was used to reduce pressure and avoid mechanical vibrations and system contaminations. (M.C.K.) [pt

  16. Superhydrophobic surfaces: from fluid mechanics to optics

    NARCIS (Netherlands)

    Rathgen, H.


    In this thesis optical diraction was used to study the static and dynamic properties of microscopic liquid-gas interfaces that span between adjacent ridges of a superhydrophobic surface. An observed interference phenomenon at grazing incident angle led to the development of optical gratings with a

  17. Optical forces through guided light deflections

    DEFF Research Database (Denmark)

    Palima, Darwin; Bañas, Andrew Rafael; Vizsnyiczai, Gaszton


    . In this work we look into the object shaping aspect and its potential for controlled optical manipulation. Using a simple bent waveguide as example, our numerical simulations show that the guided deflection of light efficiently converts incident light momentum into optical force with one order...

  18. Medication incidents reported to an online incident reporting system.

    LENUS (Irish Health Repository)

    Alrwisan, Adel


    AIMS: Approximately 20% of deaths from adverse events are related to medication incidents, costing the NHS an additional £500 million annually. Less than 5% of adverse events are reported. This study aims to assess the reporting rate of medication incidents in NHS facilities in the north east of Scotland, and to describe the types and outcomes of reported incidents among different services. Furthermore, we wished to quantify the proportion of reported incidents according to the reporters\\' profession. METHODS: A retrospective description was made of medication incidents reported to an online reporting system (DATIX) over a 46-month-period (July 2005 to April 2009). Reports originated from acute and community hospitals, mental health, and primary care facilities. RESULTS: Over the study period there were 2,666 incidents reported with a mean monthly reporting rate of 78.2\\/month (SD±16.9). 6.1% of all incidents resulted in harm, with insulin being the most commonly implicated medication. Nearly three-quarters (74.2%, n=1,978) of total incidents originated from acute hospitals. Administration incidents were implicated in the majority of the reported medication incidents (59%), followed by prescribing (10.8%) and dispensing (9.9%), while the nondescript "other medication incidents" accounted for 20.3% of total incidents. The majority of reports were made by nursing and midwifery staff (80%), with medical and dental professionals reporting the lowest number of incidents (n=56, 2%). CONCLUSIONS: The majority of medication incidents in this study were reported by nursing and midwifery staff, and were due to administration incidents. There is a clear need to elucidate the reasons for the limited contribution of the medical and dental professionals to reporting medication incidents.

  19. Applied optics

    International Nuclear Information System (INIS)

    Orszag, A.; Antonetti, A.


    The 1988 progress report, of the Applied Optics laboratory, of the (Polytechnic School, France), is presented. The optical fiber activities are focused on the development of an optical gyrometer, containing a resonance cavity. The following domains are included, in the research program: the infrared laser physics, the laser sources, the semiconductor physics, the multiple-photon ionization and the nonlinear optics. Investigations on the biomedical, the biological and biophysical domains are carried out. The published papers and the congress communications are listed [fr

  20. Hamilton's Optics

    Indian Academy of Sciences (India)

    IAS Admin

    Hamiton, optics, wavefronts, characterisic function, conical refraction. . Hamilton's Optics. The Power of Wavefronts. Rajaram Nityananada. Building on work by Fermat and Huygens, Hamil- ton transformed the study of geometrical optics in his very first paper, presented when still in his teens. His 'characteristic function' was ...

  1. Beam conditioning multilayer optics for laboratory x-ray sources (United States)

    Platonov, Yuriy; Verman, Boris; Jiang, Licai; Kim, Bonglea


    Practically, all modern x-ray diffractometers, SAXS, TXRF systems and many other laboratory X-ray instruments are equipped with multilayer X-ray optics. It is due to a much higher flux these instruments have comparing with those having no optics or having a grazing incidence optics without multilayer coatings. There are variety of the multilayer optics designs - from one bounce collimating parabolic mirror to four corners double bounce focusing mirrors. Design of multilayer optics depends on application, X-ray source parameters, requirements on divergence, focal spot, available room for the optics, manufacturing capability and cost. Key characteristics of the optics, requirements on multilayers d-spacing accuracy, optics slope errors, and substrates surface roughness are discussed in the paper. Different optics designs are considered including recently developed optics for a laboratory topography system and a Hybrid optics combining multilayer and crystal optics for XRR and XRD.

  2. Incident users of antipsychotics

    DEFF Research Database (Denmark)

    Baandrup, Lone; Kruse, Marie


    PURPOSE: In Denmark, as well as in many other countries, consumption of antipsychotics is on the rise, partly due to increasing off-label use. The aim of this study was to analyze and quantify the extent of off-label use and polypharmacy in incident users of antipsychotic medication, and to examine...... initial antipsychotic prescribing patterns and associated use of mental health care services. METHOD: Population-based cohort study linking the following Danish national registers: the Central Psychiatric Research Register, the Register of Medicinal Product Statistics, and Statistics Denmark. RESULTS...

  3. Improving freight crash incident management. (United States)


    The objective of this study was to determine the most effective way to mitigate the effect of freight : crash incidents on Louisiana freeways. Candidate incident management strategies were reviewed from : practice in other states and from those publi...

  4. Common Causes of Pesticide Incidents (United States)

    There are many types of pesticide incidents. EPA staff analyze pesticide incident reports involving people (including children and farm workers), pets, domestic animals, wildlife including bees and other pollinators, and the environment.

  5. Increasing incidence of pyogenic spondylodiscitis

    DEFF Research Database (Denmark)

    Kehrer, Michala; Pedersen, Court; Jensen, Thøger G


    Smaller studies indicate that the incidence of pyogenic spondylodiscitis is increasing, possible related to a growing elderly population. Data supporting this is sparse, and we therefore studied patient characteristics and changes in spondylodiscitis incidence 1995-2008.......Smaller studies indicate that the incidence of pyogenic spondylodiscitis is increasing, possible related to a growing elderly population. Data supporting this is sparse, and we therefore studied patient characteristics and changes in spondylodiscitis incidence 1995-2008....

  6. Nonlinear optics

    CERN Document Server

    Boyd, Robert W


    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  7. Optical fibres

    CERN Document Server

    Geisler, J; Boutruche, J P


    Optical Fibers covers numerous research works on the significant advances in optical fibers, with particular emphasis on their application.This text is composed of three parts encompassing 15 chapters. The first part deals with the manufacture of optical fibers and the materials used in their production. The second part describes optical-fiber connectors, terminals and branches. The third part is concerned with the major optoelectronic components encountered in optical-communication systems.This book will be of value to research scientists, engineers, and patent workers.

  8. Optical interconnects

    CERN Document Server

    Chen, Ray T


    This book describes fully embedded board level optical interconnect in detail including the fabrication of the thin-film VCSEL array, its characterization, thermal management, the fabrication of optical interconnection layer, and the integration of devices on a flexible waveguide film. All the optical components are buried within electrical PCB layers in a fully embedded board level optical interconnect. Therefore, we can save foot prints on the top real estate of the PCB and relieve packaging difficulty reduced by separating fabrication processes. To realize fully embedded board level optical

  9. Atom optics

    International Nuclear Information System (INIS)

    Balykin, V. I.; Jhe, W.


    Atom optics, in analogy to neutron and electron optics, deals with the realization of as a traditional elements, such as lenes, mirrors, beam splitters and atom interferometers, as well as a new 'dissipative' elements such as a slower and a cooler, which have no analogy in an another types of optics. Atom optics made the development of atom interferometer with high sensitivity for measurement of acceleration and rotational possible. The practical interest in atom optics lies in the opportunities to create atom microprobe with atom-size resolution and minimum damage of investigated objects. (Cho, G. S.)

  10. Incident Management: Process into Practice (United States)

    Isaac, Gayle; Moore, Brian


    Tornados, shootings, fires--these are emergencies that require fast action by school district personnel, but they are not the only incidents that require risk management. The authors have introduced the National Incident Management System (NIMS) and the Incident Command System (ICS) and assured that these systems can help educators plan for and…

  11. Applied optics and optical design

    CERN Document Server

    Conrady, Alexander Eugen


    ""For the optical engineer it is an indispensable work."" - Journal, Optical Society of America""As a practical guide this book has no rival."" - Transactions, Optical Society""A noteworthy contribution,"" - Nature (London)Part I covers all ordinary ray-tracing methods, together with the complete theory of primary aberrations and as much of higher aberration as is needed for the design of telescopes, low-power microscopes and simple optical systems. Chapters: Fundamental Equations, Spherical Aberration, Physical Aspect of Optical Images, Chromatic Aberration, Design of Achromatic Object-Glass

  12. Solar cell angle of incidence corrections (United States)

    Burger, Dale R.; Mueller, Robert L.


    Literature on solar array angle of incidence corrections was found to be sparse and contained no tabular data for support. This lack along with recent data on 27 GaAs/Ge 4 cm by 4 cm cells initiated the analysis presented in this paper. The literature cites seven possible contributors to angle of incidence effects: cosine, optical front surface, edge, shadowing, UV degradation, particulate soiling, and background color. Only the first three are covered in this paper due to lack of sufficient data. The cosine correction is commonly used but is not sufficient when the incident angle is large. Fresnel reflection calculations require knowledge of the index of refraction of the coverglass front surface. The absolute index of refraction for the coverglass front surface was not known nor was it measured due to lack of funds. However, a value for the index of refraction was obtained by examining how the prediction errors varied with different assumed indices and selecting the best fit to the set of measured values. Corrections using front surface Fresnel reflection along with the cosine correction give very good predictive results when compared to measured data, except there is a definite trend away from predicted values at the larger incident angles. This trend could be related to edge effects and is illustrated by a use of a box plot of the errors and by plotting the deviation of the mean against incidence angle. The trend is for larger deviations at larger incidence angles and there may be a fourth order effect involved in the trend. A chi-squared test was used to determine if the measurement errors were normally distributed. At 10 degrees the chi-squared test failed, probably due to the very small numbers involved or a bias from the measurement procedure. All other angles showed a good fit to the normal distribution with increasing goodness-of-fit as the angles increased which reinforces the very small numbers hypothesis. The contributed data only went to 65 degrees

  13. Grazing-incidence optical magnetic recording with super-resolution


    Gunther Scheunert; Sidney. R. Cohen; René Kullock; Ryan McCarron; Katya Rechev; Ifat Kaplan-Ashiri; Ora Bitton; Paul Dawson; Bert Hecht; Dan Oron


    Heat-assisted magnetic recording (HAMR) is often considered the next major step in the storage industry: it is predicted to increase the storage capacity, the read/write speed and the data lifetime of future hard disk drives. However, despite more than a decade of development work, the reliability is still a prime concern. Featuring an inherently fragile surface-plasmon resonator as a highly localized heat source, as part of a near-field transducer (NFT), the current industry concepts still f...

  14. Optics Express


    Poon, Ting-Chung; Doh, K. B.


    The Hilbert transform as been investigated abundantly in coherent imaging. To the best of our knowledge, it is for the first time investigated in the context of incoherent imaging. We present a two-pupil optical heterodyne scanning system and analyze mathematically the design of its two pupils such that the optical system can perform the Hilbert transform on incoherent objects. Computer simulations of the idea clarify the theoretical results. (c) 2007 Optical Society of America.

  15. Optical electronics

    CERN Document Server

    Yariv, Amnon


    This classic text introduces engineering students to the first principles of major phenomena and devices of optoelectronics and optical communication technology. Yariv's "first principles" approach employs real-life examples and extensive problems. The text includes separate chapters on quantum well and semiconductor lasers, as well as phase conjugation and its applications. Optical fiber amplification, signal and noise considerations in optical fiber systems, laser arrays and distributed feedback lasers all are covered extensively in major sections within chapters.

  16. Optic nerve hypoplasia

    Directory of Open Access Journals (Sweden)

    Savleen Kaur


    Full Text Available Optic nerve hypoplasia (ONH is a congenital anomaly of the optic disc that might result in moderate to severe vision loss in children. With a vast number of cases now being reported, the rarity of ONH is obviously now refuted. The major aspects of ophthalmic evaluation of an infant with possible ONH are visual assessment, fundus examination, and visual electrophysiology. Characteristically, the disc is small, there is a peripapillary double-ring sign, vascular tortuosity, and thinning of the nerve fiber layer. A patient with ONH should be assessed for presence of neurologic, radiologic, and endocrine associations. There may be maternal associations like premature births, fetal alcohol syndrome, maternal diabetes. Systemic associations in the child include endocrine abnormalities, developmental delay, cerebral palsy, and seizures. Besides the hypoplastic optic nerve and chiasm, neuroimaging shows abnormalities in ventricles or white- or gray-matter development, septo-optic dysplasia, hydrocephalus, and corpus callosum abnormalities. There is a greater incidence of clinical neurologic abnormalities in patients with bilateral ONH (65% than patients with unilateral ONH. We present a review on the available literature on the same to urge caution in our clinical practice when dealing with patients with ONH. Fundus photography, ocular coherence tomography, visual field testing, color vision evaluation, neuroimaging, endocrinology consultation with or without genetic testing are helpful in the diagnosis and management of ONH. (Method of search: MEDLINE, PUBMED.

  17. Optical Computing With Nonlinear Optics (United States)

    Khitrova, Galina; Gibbs, Hyatt; Peyghambarian, Nasser


    Nonlinear optics is becoming a new thrust in the field of optical computing and signal processing.14 Optical nonlinearity makes the device's transmission intensity dependent, so one can obtain the thresholding needed for logic decisionmaking. Thresholding is essential to digital optical computing, neural nets, and associative memories. GaAs etalons exhibit many of the characteristics desirable for the nonlinear devices including high speed (picosecond) and diode-laser compatability. However, demonstrations of the use of nonlinear decisionmaking for optical computing have used ZnS or ZnSe interference filters. They are slow (millisecond), but they can be used with the visible 514.5-nm output of an argon laser. We have used such filters to demonstrate all-optical logic operations, one-bit addition by symbolic substitution, and recognition of a three-spot pattern in an arbitrary 2 x 8 array of input beams. The application to associative memories is under study.

  18. Polarization Optics


    Fressengeas, Nicolas


    The physics of polarization optics *Polarized light propagation *Partially polarized light; DEA; After a brief introduction to polarization optics, this lecture reviews the basic formalisms for dealing with it: Jones Calculus for totally polarized light and Stokes parameters associated to Mueller Calculus for partially polarized light.

  19. Optical Computing

    Indian Academy of Sciences (India)

    Integration (VLSI) technology with smaller device dimensions and greater complexity. The smallest .... on a chip, much less than what was mentioned earlier (optical integration is still in its infancy compared to electronics). ..... Optical tunnel devices are under continuous development varying from small caliber endoscopes to ...

  20. Optical Computing

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 6. Optical Computing - Optical Components and Storage Systems. Debabrata Goswami. General Article Volume 8 Issue 6 June 2003 pp 56-71. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Optical biosensors. (United States)

    Damborský, Pavel; Švitel, Juraj; Katrlík, Jaroslav


    Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  2. Goiania incident case study

    International Nuclear Information System (INIS)

    Petterson, J.S.


    The reasons for wanting to document this case study and present the findings are simple. According to USDOE technical risk assessments (and our own initial work on the Hanford socioeconomic study), the likelihood of a major accident involving exposure to radioactive materials in the process of site characterization, construction, operation, and closure of a high-level waste repository is extremely remote. Most would agree, however, that there is a relatively high probability that a minor accident involving radiological contamination will occur sometime during the lifetime of the repository -- for example, during transport, at an MRS site or at the permanent site itself during repacking and deposition. Thus, one of the major concerns of the Yucca Mountain Socioeconomic Study is the potential impact of a relatively minor radiation-related accident. A large number of potential impact of a relatively minor radiation-related accident. A large number of potential accident scenarios have been under consideration (such as a transportation or other surface accident which results in a significant decline in tourism, the number of conventions, or the selection of Nevada as a retirement residence). The results of the work in Goiania make it clear, however, that such a significant shift in established social patterns and trends is not likely to occur as a direct outcome of a single nuclear-related accident (even, perhaps, a relatively major one), but rather, are likely to occur as a result of the enduring social interpretations of such an accident -- that is, as a result of the process of understanding, communicating, and socially sustaining a particular set of associations with respect to the initial incident

  3. Geometric Phase Generated Optical Illusion. (United States)

    Yue, Fuyong; Zang, Xiaofei; Wen, Dandan; Li, Zile; Zhang, Chunmei; Liu, Huigang; Gerardot, Brian D; Wang, Wei; Zheng, Guoxing; Chen, Xianzhong


    An optical illusion, such as "Rubin's vase", is caused by the information gathered by the eye, which is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source. Metasurfaces are metamaterials of reduced dimensionality which have opened up new avenues for flat optics. The recent advancement in spin-controlled metasurface holograms has attracted considerate attention, providing a new method to realize optical illusions. We propose and experimentally demonstrate a metasurface device to generate an optical illusion. The metasurface device is designed to display two asymmetrically distributed off-axis images of "Rubin faces" with high fidelity, high efficiency and broadband operation that are interchangeable by controlling the helicity of the incident light. Upon the illumination of a linearly polarized light beam, the optical illusion of a 'vase' is perceived. Our result provides an intuitive demonstration of the figure-ground distinction that our brains make during the visual perception. The alliance between geometric metasurface and the optical illusion opens a pathway for new applications related to encryption, optical patterning, and information processing.

  4. Fiber optic coupled optical sensor (United States)

    Fleming, Kevin J.


    A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

  5. Real time freeway incident detection. (United States)


    The US Department of Transportation (US-DOT) estimates that over half of all congestion : events are caused by highway incidents rather than by rush-hour traffic in big cities. Real-time : incident detection on freeways is an important part of any mo...

  6. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas


    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  7. Integrated optics

    International Nuclear Information System (INIS)

    Jekowski, J.; Aeby, I.


    The purpose of the R and D effort is to establish a baseline technology in integrated optic techniques within the EMG. Significant investment presently being made by industry in this area indicates that this technology may offer an alternative solution for high speed digital data acquisition and transmission. The objectives of this year's integrated optics program were three-fold: (1) to establish a literature search and maintain industry contacts in an attempt to make the needs of the Weapons Test Program known; (2) to assist the Las Vegas Hybrid facility in establising integrated optic fabrication techniques for their new Thin Film Laboratory; and (3) to conduct basic experiments at Los Alamos in the construction of photolithograhicaly etched plastic film devices. The report describes the successful completion of preliminary investigations into photolithographic techniques and continuing investigations into newly announced integrated optic techniques and devices that would be applicable to the weapons test program

  8. Optical Spectroscopy

    DEFF Research Database (Denmark)

    Thyrhaug, Erling

    The work presented in this thesis is broadly concerned with how complexation reactions and molecular motion can be characterized with the standard techniques in optical spectroscopy. The thesis aims to show a relatively broad range of methods for probing physico-chemical properties in fluorophore...... containing systems and are characterized using techniques in optical spectroscopy. Of the standard techniques in optical spectroscopy, particular attention has been paid to those based on time-resolved measurements and polarization, which is reflected in the experiment design in the projects. Not all...... reactions by optical spectroscopy. In project 1 simple steady-state absorption and fluorescence spectroscopy is used to determine the stoichiometries and equilibrium constants in the inclusion complex formation between cyclodextrins and derivatives of the water-insoluble oligo(phenylene vinylene) in aqueous...

  9. Quantum optics

    DEFF Research Database (Denmark)

    Andersen, Ulrik Lund


    Further sensitivity improvements are required before advanced optical interferometers will be able to measure gravitational waves. A team has now shown that introducing quantum squeezing of light may help to detect these elusive waves.......Further sensitivity improvements are required before advanced optical interferometers will be able to measure gravitational waves. A team has now shown that introducing quantum squeezing of light may help to detect these elusive waves....

  10. Ocean optics

    Energy Technology Data Exchange (ETDEWEB)

    Spinard, R.W.; Carder, K.L.; Perry, M.J.


    This volume is the twenty fifth in the series of Oxford Monographs in Geology and Geophysics. The propagation off light in the hydra-atmosphere systems is governed by the integral-differential Radiative Transfer Equation (RTE). Closure and inversion are the most common techniques in optical oceanography to understand the most basic principles of natural variability. Three types of closure are dealt with: scale closure, experimental closure, and instrument closure. The subject is well introduced by Spinard et al. in the Preface while Howard Gordon in Chapter 1 provides an in-depth introduction to the RTE and its inherent problems. Inherent and apparent optical properties are dealt with in Chapter 2 by John Kirk and the realities of optical closure are presented in the following chapter by Ronald Zaneveld. The balance of the papers in this volume is quite varied. The early papers deal in a very mathematical manner with the basics of radiative transfer and the relationship between inherent and optical properties. Polarization of sea water is discussed in a chapter that contains a chronological listing of discoveries in polarization, starting at about 1000 AD with the discovery of dichroic properties of crystals by the Vikings and ending with the demonstration of polarotaxis in certain marine organisms by Waterman in 1972. Chapter 12 on Raman scattering in pure water and the pattern recognition techniques presented in Chapter 13 on the optical effects of large particles may be of relevance to fields outside ocean optics.

  11. Anterior ischemic optic neuropathy in association with optic nervehead drusen

    Directory of Open Access Journals (Sweden)

    Bharathi Megur


    Full Text Available Optic nerve head drusen (ONHD are incidental ophthalmologic finding in the optic nerve. Patients with ONHD are often asymptomatic, but sometimes present with transient visual obscuration′s (TVO, the reported incidence of which is 8.6%. Optic nerve head drusen are of two types: Superficial; visible and deep. The deep-buried drusen mimic papilledema. Because of the varied presentation deep-buried drusen pose a diagnostic challenge to the ophthalmologists. In young patients, they are mistaken for papilledema as it is clinically difficult to detect a buried drusen in the optic nerve head, but are seen on the surface with aging as the retinal nerve fiber layer thins out. They are observed as pale yellow lesions more often located towards the poles. Clinical examination aided with diagnostic tests like computed tomography (CT orbits and ultrasound B scan can help establish the diagnosis. Herein, we report a rare case of optic nerve head drusen in a young lady, who presented with loss of vision and clinical evaluation and investigations suggested ONHD with anterior ischemic optic neuropathy.

  12. Optical Bistability For Optical Signal Processing And Computing (United States)

    Peyghambarian, N.; Gibbs, H. M.


    In this paper we present the basic principles of optical bistability and summarize the current advances in semiconductor optical switching, with emphasis on recent results in GaAs, CuCI, InAs, InSb, CdS, ZnS, and ZnSe etalons. These devices have great potential for applications involving optical signal processing and computing. As an example, we discuss the use of arrays of bistable devices for parallel optical processing and for addressable spatial light modulators. The use of nonlinear etalons as optical gates is also illustrated. To date, GaAs devices have shown the most favorable characteristics for practical applications. They operate at room temperature with a few milliwatts of power using a laser diode as the only light source. Quasi-cw operation and optical fiber signal regeneration have also been demonstrated. A GaAs NOR gate operates in 1 ps with <3 pJ incident energy; this, of course, implies a 1 ps switch-on time for a bistable etalon.

  13. Decreasing incidence rates of bacteremia

    DEFF Research Database (Denmark)

    Nielsen, Stig Lønberg; Pedersen, C; Jensen, T G


    BACKGROUND: Numerous studies have shown that the incidence rate of bacteremia has been increasing over time. However, few studies have distinguished between community-acquired, healthcare-associated and nosocomial bacteremia. METHODS: We conducted a population-based study among adults with first......-acquired, 50.0 for healthcare-associated and 66.7 for nosocomial bacteremia. During 2000-2008, the overall incidence rate decreased by 23.3% from 254.1 to 198.8 (3.3% annually, p ...) and the incidence rate of nosocomial bacteremia decreased by 28.9% from 82.2 to 56.0 (4.2% annually, p

  14. Traffic incident management resource management. (United States)


    The necessity of a multi-disciplinary approach involving law enforcement, fire and rescue, transportation, towing and recovery, and others has been well-recognized and integrated into incident management operations. This same multidisciplinar...

  15. Police Incident Blotter (30 Day) (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The 30 Day Police Blotter contains the most recent initial crime incident data, updated on a nightly basis. All data is reported at the block/intersection level,...

  16. Regional comparison of cancer incidence

    International Nuclear Information System (INIS)

    Obralic, N.; Gavrankapetanovic, F.; Dizdarevic, Z.; Duric, O.; Sisic, F.; Selak, I.; Balta, S.; Nakas, B.


    Background. Due to specific war and post-war situation in Balkan region, differences in the number, type, development, biological course, treatment of malignant tumours and its outcome are possible. In order to perceive the situation realistically, it is necessary to gather continuously exact data about malignant tumours and compare them with the data from other European and world countries.The aim of the study was to collect and analyse the data on cancer incidence in the region of Sarajevo city, which represents a symbol of difficult times in the recent past, and to compare it to the incidence in the neighbouring countries. Patients and methods. Data on all newly diagnosed cancer cases, permanent residents of Sarajevo Canton, in the years 1999 and 2000 were collected. Crude incidence rate has been calculated according to the years observed, gender and localizations of the disease The data were compared to the cancer registries of Slovenia and Croatia and were observed in the light of specific local situation. Results. The crude cancer incidence of all sites but skin was the highest in both years and by both genders in Croatia. The incidence of the most common tumours (lung and breast cancer) was similar in all three countries. The differences in the incidence between both genders in the Sarajevo canton were registered in laryngeal and urinary bladder cancer, as well as in bone and cartilage sarcoma. Cervical cancer had extremely high incidence and was high up on the incidence list in the Sarajevo canton, which correlates with the data in developing countries. The incidence of other tumours in the post-war period is reaching expected numbers. Conclusions. It is difficult to identify whether the war and post-war stress, irregular and insufficient nutrition during and after the siege of the city of Sarajevo or some other factor influenced the cancer incidence among exposed population. The prevalence of smoking in the whole region is extremely high, in Bosnia and

  17. QUANTUM OPTICS. Universal linear optics. (United States)

    Carolan, Jacques; Harrold, Christopher; Sparrow, Chris; Martín-López, Enrique; Russell, Nicholas J; Silverstone, Joshua W; Shadbolt, Peter J; Matsuda, Nobuyuki; Oguma, Manabu; Itoh, Mikitaka; Marshall, Graham D; Thompson, Mark G; Matthews, Jonathan C F; Hashimoto, Toshikazu; O'Brien, Jeremy L; Laing, Anthony


    Linear optics underpins fundamental tests of quantum mechanics and quantum technologies. We demonstrate a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons, and their measurement with a 12-single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with an average fidelity of 0.999 ± 0.001. Our system can be rapidly reprogrammed to implement these and any other linear optical protocol, pointing the way to applications across fundamental science and quantum technologies. Copyright © 2015, American Association for the Advancement of Science.

  18. Asymptotics for incidence matrix classes


    Cameron, Peter; Prellberg, Thomas; Stark, Dudley


    We define {\\em incidence matrices} to be zero-one matrices with no zero rows or columns. A classification of incidence matrices is considered for which conditions of symmetry by transposition, having no repeated rows/columns, or identification by permutation of rows/columns are imposed. We find asymptotics and relationships for the number of matrices with $n$ ones in these classes as $n\\to\\infty$.

  19. Incidence Handling and Response System


    Kalbande, Prof. Dhananjay R.; Thampi, Dr. G. T.; Singh, Mr. Manish


    A computer network can be attacked in a number of ways. The security-related threats have become not only numerous but also diverse and they may also come in the form of blended attacks. It becomes difficult for any security system to block all types of attacks. This gives rise to the need of an incidence handling capability which is necessary for rapidly detecting incidents, minimizing loss and destruction, mitigating the weaknesses that were exploited and restoring the computing services. I...

  20. Cancer incidence in Spain, 2015. (United States)

    Galceran, J; Ameijide, A; Carulla, M; Mateos, A; Quirós, J R; Rojas, D; Alemán, A; Torrella, A; Chico, M; Vicente, M; Díaz, J M; Larrañaga, N; Marcos-Gragera, R; Sánchez, M J; Perucha, J; Franch, P; Navarro, C; Ardanaz, E; Bigorra, J; Rodrigo, P; Bonet, R Peris


    Periodic cancer incidence estimates of Spain from all existing population-based cancer registries at any given time are required. The objective of this study was to present the current situation of cancer incidence in Spain. The Spanish Network of Cancer Registries (REDECAN) estimated the numbers of new cancer cases occurred in Spain in 2015 by applying the incidence-mortality ratios method. In the calculus, incidence data from population-based cancer registries and mortality data of all Spain were used. In 2015, nearly a quarter of a million new invasive cancer cases were diagnosed in Spain, almost 149,000 in men (60.0%) and 99,000 in women. Globally, the five most common cancers were those of colon-rectum, prostate, lung, breast and urinary bladder. By gender, the four most common cancers in men were those of prostate (22.4%), colon-rectum (16.6%), lung (15.1%) and urinary bladder (11.7%). In women, the most common ones were those of breast (28.0%), colon-rectum (16.9%), corpus uteri (6.2%) and lung (6.0%). In recent years, cancer incidence in men seems to have stabilized due to the fact that the decrease in tobacco-related cancers compensates for the increase in other types of cancer like those of colon and prostate. In women, despite the stabilization of breast cancer incidence, increased incidence is due, above all, to the rise of colorectal and tobacco-related cancers. To reduce these incident cancer cases, improvement of smoking control policies and extension of colorectal cancer screening should be the two priorities in cancer prevention for the next years.

  1. Cyber Incidents Involving Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Robert J. Turk


    The Analysis Function of the US-CERT Control Systems Security Center (CSSC) at the Idaho National Laboratory (INL) has prepared this report to document cyber security incidents for use by the CSSC. The description and analysis of incidents reported herein support three CSSC tasks: establishing a business case; increasing security awareness and private and corporate participation related to enhanced cyber security of control systems; and providing informational material to support model development and prioritize activities for CSSC. The stated mission of CSSC is to reduce vulnerability of critical infrastructure to cyber attack on control systems. As stated in the Incident Management Tool Requirements (August 2005) ''Vulnerability reduction is promoted by risk analysis that tracks actual risk, emphasizes high risk, determines risk reduction as a function of countermeasures, tracks increase of risk due to external influence, and measures success of the vulnerability reduction program''. Process control and Supervisory Control and Data Acquisition (SCADA) systems, with their reliance on proprietary networks and hardware, have long been considered immune to the network attacks that have wreaked so much havoc on corporate information systems. New research indicates this confidence is misplaced--the move to open standards such as Ethernet, Transmission Control Protocol/Internet Protocol, and Web technologies is allowing hackers to take advantage of the control industry's unawareness. Much of the available information about cyber incidents represents a characterization as opposed to an analysis of events. The lack of good analyses reflects an overall weakness in reporting requirements as well as the fact that to date there have been very few serious cyber attacks on control systems. Most companies prefer not to share cyber attack incident data because of potential financial repercussions. Uniform reporting requirements will do much to make this

  2. Large depth of focus dynamic micro integral imaging for optical see-through augmented reality display using a focus-tunable lens. (United States)

    Shen, Xin; Javidi, Bahram


    We have developed a three-dimensional (3D) dynamic integral-imaging (InIm)-system-based optical see-through augmented reality display with enhanced depth range of a 3D augmented image. A focus-tunable lens is adopted in the 3D display unit to relay the elemental images with various positions to the micro lens array. Based on resolution priority integral imaging, multiple lenslet image planes are generated to enhance the depth range of the 3D image. The depth range is further increased by utilizing both the real and virtual 3D imaging fields. The 3D reconstructed image and the real-world scene are overlaid using an optical see-through display for augmented reality. The proposed system can significantly enhance the depth range of a 3D reconstructed image with high image quality in the micro InIm unit. This approach provides enhanced functionality for augmented information and adjusts the vergence-accommodation conflict of a traditional augmented reality display.

  3. Semiconductor Optics

    CERN Document Server

    Klingshirn, Claus F


    This updated and enlarged new edition of Semiconductor Optics provides an introduction to and an overview of semiconductor optics from the IR through the visible to the UV, including linear and nonlinear optical properties, dynamics, magneto and electrooptics, high-excitation effects and laser processes, some applications, experimental techniques and group theory. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered extend from physics to materials science and optoelectronics. Significantly updated chapters add coverage of current topics such as electron hole plasma, Bose condensation of excitons and meta materials. Over 120 problems, chapter introductions and a detailed index make it the key textbook for graduate students in physics. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered ...

  4. Optical memory (United States)

    Mao, Samuel S; Zhang, Yanfeng


    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  5. RADIANCE AND PHOTON NOISE: Imaging in geometrical optics, physical optics, quantum optics and radiology. (United States)

    Barrett, Harrison H; Myers, Kyle J; Caucci, Luca


    A fundamental way of describing a photon-limited imaging system is in terms of a Poisson random process in spatial, angular and wavelength variables. The mean of this random process is the spectral radiance. The principle of conservation of radiance then allows a full characterization of the noise in the image (conditional on viewing a specified object). To elucidate these connections, we first review the definitions and basic properties of radiance as defined in terms of geometrical optics, radiology, physical optics and quantum optics. The propagation and conservation laws for radiance in each of these domains are reviewed. Then we distinguish four categories of imaging detectors that all respond in some way to the incident radiance, including the new category of photon-processing detectors. The relation between the radiance and the statistical properties of the detector output is discussed and related to task-based measures of image quality and the information content of a single detected photon.

  6. Optical dosimeter

    International Nuclear Information System (INIS)

    Drukaroff, I.; Fishman, R.


    A reflecting optical dosimeter is a thin block of optical material having an input light pipe at one corner and an output light pipe at another corner, arranged so that the light path includes several reflections off the edges of the block to thereby greatly extend its length. In a preferred embodiment, one corner of the block is formed at an angle so that after the light is reflected several times between two opposite edges, it is then reflected several more times between the other two edges

  7. Statistical optics

    CERN Document Server

    Goodman, Joseph W


    This book discusses statistical methods that are useful for treating problems in modern optics, and the application of these methods to solving a variety of such problems This book covers a variety of statistical problems in optics, including both theory and applications.  The text covers the necessary background in statistics, statistical properties of light waves of various types, the theory of partial coherence and its applications, imaging with partially coherent light, atmospheric degradations of images, and noise limitations in the detection of light. New topics have been introduced i

  8. Quantum optics

    International Nuclear Information System (INIS)

    Flytzanis, C.


    The 1988 progress report of the Quantum Optics laboratory (Polytechnic School, France) is presented. The research program is focused on the behavior of dense and dilute materials submitted to short and high-intensity light radiation fields. Nonlinear optics techniques, with time and spatial resolution, are developed. An important research activity concerns the investigations on the interactions between the photon beams and the inhomogeneous or composite materials, as well as the artificial microstructures. In the processes involving molecular beams and surfaces, the research works on the photophysics of surfaces and the molecule-surface interactions, are included [fr

  9. Breast cancer incidence in Mongolia (United States)

    Altantsetseg, Dalkhjav; Davaasambuu, Ganmaa; Rich-Edwards, Janet; Davaalkham, Dambadarjaa; Tretli, Steinar; Hoover, Robert N.; Frazier, A. Lindsay


    Purpose Data on international variation in breast cancer incidence may help to identify additional risk factors. Substantially lower breast cancer rates in Asia than in North America and Western Europe are established, but differences within Asia have been largely ignored despite heterogeneity in lifestyles and environments. Mongolia’s breast cancer experience is of interest because of its shared genetics but vastly different diet compared with other parts of Asia. Methods Age-standardized breast cancer incidence and mortality rates obtained from the International Association of Cancer Registries are presented for several Asian countries. Mongolian incidence rates obtained from its cancer registry describe incidence within the country. Results Breast cancer incidence in Mongolia (age standardized 8.0/100,000) is almost a third of rates in China (21.6/100,000), and over five times that of Japan (42.7/100,000) and Russia (43.2/100,000). Rates within Mongolia appear to have increased slightly over the last decade and are higher in urban than rural areas (annual percentage increase of age-standardized rates from 1998 to 2005 was 3.60 and 2.57%, respectively). The increase in breast cancer incidence with age plateaus at menopause, as in other Asian populations. Conclusions Mongolia’s low breast cancer incidence is of particular interest because of their unusual diet (primarily red meat and dairy) compared with other Asian countries. More intensive study of potential dietary, reproductive and lifestyle factors in Mongolia with comparison to other Asian populations may provide more clarity in what drives the international breast cancer rate differences. PMID:22543542

  10. Optics with an Atom Laser Beam

    International Nuclear Information System (INIS)

    Bloch, Immanuel; Koehl, Michael; Greiner, Markus; Haensch, Theodor W.; Esslinger, Tilman


    We report on the atom optical manipulation of an atom laser beam. Reflection, focusing, and its storage in a resonator are demonstrated. Precise and versatile mechanical control over an atom laser beam propagating in an inhomogeneous magnetic field is achieved by optically inducing spin flips between atomic ground states with different magnetic moment. The magnetic force acting on the atoms can thereby be effectively switched on and off. The surface of the atom optical element is determined by the resonance condition for the spin flip in the inhomogeneous magnetic field. More than 98% of the incident atom laser beam is reflected specularly

  11. Information sharing for traffic incident management. (United States)


    Traffic incident management focuses on developing procedures, implementing policies, and deploying technologies to more quickly identify incidents, improve response times, and more effectively and efficiently manage the incident scene. Because so man...

  12. Diophantine Optics (United States)

    Rouan, D.


    What I call Diophantine optics is the exploitation in optics of some remarkable algebraic relations between powers of integers. The name comes from Diophantus of Alexandria, a greek mathematician, known as the father of algebra. He studied polynomial equations with integer coefficients and integer solutions, called diophantine equations. Since constructive or destructive interferences are playing with optical path differences which are multiple integer (odd or even) of λ/2 and that the complex amplitude is a highly non-linear function of the optical path difference (or equivalently of the phase), one can understand that any Taylor development of this amplitude implies powers of integers. This is the link with Diophantine equations. We show how, especially in the field of interferometry, remarkable relations between powers of integers can help to solve several problems, such as achromatization of a phase shifter or deep nulling efficiency. It appears that all the research that was conducted in this frame of thinking, relates to the field of detection of exoplanets, a very active domain of astrophysics today.

  13. Optical profilometer (United States)

    Wieloszyńska, Aleksandra; StrÄ kowski, Marcin


    The profilometry plays a huge role in the most fields of science and technology. It allows to measure the profile of the surface with high-resolution. This technique is used in the fields like optic, electronic, medicine, automotive, and much more. The aim of the current work was to design and build optical profilometer based on the interference phenomena. The developed device has been working with He-Ne laser (632.8 nm). The optical parts have been chosen in order to reach the sized 2.0 mm x 1.6 mm of scanning area. The setup of the profilometer is based on Twyman-Green interferometer. Therefore, the phase distribution of the backreflected light from measured surface is recorded. The measurements are carried out with the aid of multiframe algorithms. In this approach we have used the Hariharan algorithm to obtain the exact value of the recorded phase. During tests, which have been carried out in order to check the functionality of the device, the interference patterns have been recoded and processed in order to obtain the 3D profile of measured surface. In this contribution the setup of the optical system, as well as signal processing methods are going to be presented. The brief discussion about the advantages and disadvantages, and usefulness of this approach will be carried out.

  14. Optical fibres

    CERN Multimedia


    These optical fibres are used to detect particles passing through in bunches. Made from scintillating material, the fibres glow when a high energy particle passes through them. These detectors are known as spaghetti detectors and are used to measure the energy of particles.

  15. Optical geometry

    International Nuclear Information System (INIS)

    Robinson, I.; Trautman, A.


    The geometry of classical physics is Lorentzian; but weaker geometries are often more appropriate: null geodesics and electromagnetic fields, for example, are well known to be objects of conformal geometry. To deal with a single null congruence, or with the radiative electromagnetic fields associated with it, even less is needed: flag geometry for the first, optical geometry, with which this paper is chiefly concerned, for the second. The authors establish a natural one-to-one correspondence between optical geometries, considered locally, and three-dimensional Cauchy-Riemann structures. A number of Lorentzian geometries are shown to be equivalent from the optical point of view. For example the Goedel universe, the Taub-NUT metric and Hauser's twisting null solution have an optical geometry isomorphic to the one underlying the Robinson congruence in Minkowski space. The authors present general results on the problem of lifting a CR structure to a Lorentz manifold and, in particular, to Minkowski space; and exhibit the relevance of the deviation form to this problem

  16. Optical twisters

    DEFF Research Database (Denmark)

    Daria, Vincent R.; Palima, Darwin; Glückstad, Jesper


    We describe a diffracting beam with orbital angular momentum (OAM) but with a helical profile in both phase and amplitude components of the beam. This is different from Laguerre-Gaussian (LG) beams where only the phase component has a helical profile. Such profile in LG beams introduces a phase s....... Such beams can be applied to fundamental studies of light and atoms such as in quantum entanglement of the OAM, toroidal traps for cold atoms and for optical manipulation of microscopic particles....... and linearly scaled towards no phase singularity at the centre of the beam. At the focal volume, we show that our beam forms an intensity distribution that can be accurately described as an "optical twister" as it propagates in the forward direction. Unlike LG beams, an optical twister can have minimal changes...... in radius but with a scalable OAM. Furthermore, we characterize the OAM in terms of its capacity to introduce spiral motion on particles trapped along its orbit. We also show that our "optical twister" maintains a high concentration of photons at the focus even as the topological charge is increased...

  17. Skin optics

    NARCIS (Netherlands)

    van Gemert, M. J.; Jacques, S. L.; Sterenborg, H. J.; Star, W. M.


    Quantitative dosimetry in the treatment of skin disorders with (laser) light requires information on propagation of light in the skin related to the optical properties of the individual skin layers. This involves the solution of the integro-differential equation of radiative transfer in a model

  18. Optical metrology

    CERN Document Server

    Gåsvik, Kjell J


    New material on computerized optical processes, computerized ray tracing, and the fast Fourier transform, Bibre-Bragg sensors, and temporal phase unwrapping.* New introductory sections to all chapters.* Detailed discussion on lasers and laser principles, including an introduction to radiometry and photometry.* Thorough coverage of the CCD camera.

  19. Optical Computing

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 7. Optical Computing - Research Trends. Debabrata Goswami. General Article Volume 8 Issue 7 July 2003 pp 8-21. Fulltext. Click here to view fulltext PDF. Permanent link: Keywords.

  20. Investigation of the evaporation process conditions on the optical constants of zirconia films

    International Nuclear Information System (INIS)

    Dobrowolski, J.A.; Grant, P.D.; Simpson, R.; Waldorf, A.


    Deposition parameters required for producing zirconia films for use in optical multilayer systems by electron-beam gun evaporation of zirconia and zirconium starting materials were investigated. The optical constants were determined as a function of distance, partial pressure of oxygen, and angle of incidence. The direct and reactive evaporation processes yielded ZrO 2 films with refractive indices of 2.08 and 2.14, respectively, for vapor incident on the substrate at normal incidence

  1. Image correction in magneto-optical microscopy

    DEFF Research Database (Denmark)

    Paturi, P.; Larsen, B.H.; Jacobsen, B.A.


    An image-processing procedure that assures correct determination of the magnetic field distribution of magneto-optical images is presented. The method remedies image faults resulting from sources that are proportional to the incident light intensity, such as different types of defects...

  2. Narrow linewidth pulsed optical parametric oscillator

    Indian Academy of Sciences (India)

    Abstract. Tunable narrow linewidth radiation by optical parametric oscillation has many applications, particularly in spectroscopic investigation. In this paper, different techniques such as injection seeding, use of spectral selecting element like grating, grat- ing and etalon in combination, grazing angle of incidence, entangled ...

  3. Optical Coherence and Quantum Optics

    CERN Document Server

    Mandel, Leonard


    This book presents a systematic account of optical coherence theory within the framework of classical optics, as applied to such topics as radiation from sources of different states of coherence, foundations of radiometry, effects of source coherence on the spectra of radiated fields, coherence theory of laser modes, and scattering of partially coherent light by random media. The book starts with a full mathematical introduction to the subject area and each chapter concludes with a set of exercises. The authors are renowned scientists and have made substantial contributions to many of the topi

  4. Optical Magnetometry (United States)

    Budker, Dmitry; Kimball, Derek F. Jackson


    Part I. Principles and Techniques: 1. General principles and characteristics of optical magnetometers D. F. Jackson Kimball, E. B. Alexandrov and D. Budker; 2. Quantum noise in atomic magnetometers M. V. Romalis; 3. Quantum noise, squeezing, and entanglement in radio-frequency optical magnetometers K. Jensen and E. S. Polzik; 4. Mx and Mz magnetometers E. B. Alexandrov and A. K. Vershovskiy; 5. Spin-exchange-relaxation-free (serf) magnetometers I. Savukov and S. J. Seltzer; 6. Optical magnetometry with modulated light D. F. Jackson Kimball, S. Pustelny, V. V. Yashchuk and D. Budker; 7. Microfabricated atomic magnetometers S. Knappe and J. Kitching; 8. Optical magnetometry with nitrogen-vacancy centers in diamond V. M. Acosta, D. Budker, P. R. Hemmer, J. R. Maze and R. L. Walsworth; 9. Magnetometry with cold atoms W. Gawlik and J. M. Higbie; 10. Helium magnetometers R. E. Slocum, D. D. McGregor and A. W. Brown; 11. Surface coatings for atomic magnetometry S. J. Seltzer, M.-A. Bouchiat and M. V. Balabas; 12. Magnetic shielding V. V. Yashchuk, S.-K. Lee and E. Paperno; Part II. Applications: 13. Remote detection magnetometry S. M. Rochester, J. M. Higbie, B. Patton, D. Budker, R. Holzlöhner and D. Bonaccini Calia; 14. Detection of nuclear magnetic resonance with atomic magnetometers M. P. Ledbetter, I. Savukov, S. J. Seltzer and D. Budker; 15. Space magnetometry B. Patton, A. W. Brown, R. E. Slocum and E. J. Smith; 16. Detection of biomagnetic fields A. Ben-Amar Baranga, T. G. Walker and R. T. Wakai; 17. Geophysical applications M. D. Prouty, R. Johnson, I. Hrvoic and A. K. Vershovskiy; Part III. Broader Impact: 18. Tests of fundamental physics with optical magnetometers D. F. Jackson Kimball, S. K. Lamoreaux and T. E. Chupp; 19. Nuclear magnetic resonance gyroscopes E. A. Donley and J. Kitching; 20. Commercial magnetometers and their application D. C. Hovde, M. D. Prouty, I. Hrvoic and R. E. Slocum; Index.

  5. Optical detection dental disease using polarized light (United States)

    Everett, Matthew J.; Colston, Jr., Billy W.; Sathyam, Ujwal S.; Da Silva, Luiz B.; Fried, Daniel


    A polarization sensitive optical imaging system is used to detect changes in polarization in dental tissues to aid the diagnosis of dental disease such as caries. The degree of depolarization is measured by illuminating the dental tissue with polarized light and measuring the polarization state of the backscattered light. The polarization state of this reflected light is analyzed using optical polarimetric imaging techniques. A hand-held fiber optic dental probe is used in vivo to direct the incident beam to the dental tissue and collect the reflected light. To provide depth-resolved characterization of the dental tissue, the polarization diagnostics may be incorporated into optical coherence domain reflectometry and optical coherence tomography (OCDR/OCT) systems, which enables identification of subsurface depolarization sites associated with demineralization of enamel or bone.

  6. Incidence of scabies in Belgium (United States)



    SUMMARY A prospective survey on scabies in Ghent, Belgium was performed in 2004. Sixty-four individual cases were reported, corresponding to a crude incidence rate of 28/100 000 inhabitants. The incidence was higher in the elderly (51/100 000 in persons aged >75 years) and a higher incidence was also found in immigrants (88/100 000). More than 40% of the registered scabies patients had symptoms for more than 4 weeks at the time of presentation. In 54% of the consultations, the patient had already consulted a physician for his/her skin problem. Of this group, 44% had not yet received any scabicidal treatment, indicating that scabies was not yet diagnosed or that an inappropriate treatment was prescribed. The observations suggest that the diagnosis and/or treatment of scabies in this region can still be improved. PMID:17506916

  7. Polarisation-sensitive optical elements in azobenzene polyesters and peptides

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Dam-Hansen, Carsten; Berg, Rolf Henrik


    In this article, we describe fabrication of polarisation holographic optical elements in azobenzene polyesters. Both liquid crystalline and amorphous side-chain polyesters have been utilised. Diffractive optical elements such as lenses and gratings that are sensitive to the polarisation...... of the incident light have been fabricated with polarisation holography. Computer-generated optical elements and patterns have also been written with a single polarised laser beam. Recording of polarisation defects enabling easy visualisation is also shown to be feasible in azobenzene polyesters....

  8. Metabolic Syndrome and Incident Diabetes


    Ford, Earl S.; Li, Chaoyang; Sattar, Naveed


    OBJECTIVE?Our objective was to perform a quantitative review of prospective studies examining the association between the metabolic syndrome and incident diabetes. RESEARCH DESIGN AND METHODS?Using the title terms ?diabetes? and ?metabolic syndrome? in PubMed, we searched for articles published since 1998. RESULTS?Based on the results from 16 cohorts, we performed a meta-analysis of estimates of relative risk (RR) and incident diabetes. The random-effects summary RRs were 5.17 (95% CI 3.99?6....

  9. Cardiovascular disease incidence and survival

    DEFF Research Database (Denmark)

    Byberg, Stine; Agyemang, Charles; Zwisler, Ann-Dorthe


    Studies on cardiovascular disease (CVD) incidence and survival show varying results between different ethnic groups. Our aim was to add a new dimension by exploring the role of migrant status in combination with ethnic background on incidence of-and survival from-CVD and more specifically acute...... of some types of cardiovascular disease compared to Danish-born. Family-reunified migrants on the other hand had lower rates of CVD. All migrants had better survival than Danish-born indicating that migrants may not always be disadvantaged in health....

  10. Optical loop framing

    International Nuclear Information System (INIS)

    Kalibjian, R.; Chong, Y.P.; Prono, D.S.; Cavagnolo, H.R.


    The ATA provides an electron beam pulse of 70-ns duration at a 1-Hz rate. Our present optical diagnostics technique involve the imaging of the visible light generated by the beam incident onto the plant of a thin sheet of material. It has already been demonstrated that the light generated has a sufficiently fast temporal reponse in performing beam diagnostics. Notwithstanding possible beam emittance degradation due to scattering in the thin sheet, the observation of beam spatial profiles with relatively high efficiencies has provided data complementary to that obtained from beam wall current monitors and from various x-ray probes and other electrical probes. The optical image sensor consists of a gated, intensified television system. The gate pulse of the image intensifier can be appropriately delayed to give frames that are time-positioned from the head to the tail of the beam with a minimum gate time of 5-ns. The spatial correlation of the time frames from pulse to pulse is very good for a stable electron beam; however, when instabilities do occur, it is difficult to properly assess the spatial composition of the head and the tail of the beam on a pulse-to-pulse basis. Multiple gating within a pulse duration becomes desirable but cannot be performed because the recycle time (20-ms) of the TV system is much longer than the beam pulse. For this reason we have developed an optical-loop framing technique that will allow the recording of two frames within one pulse duration with our present gated/intensified TV system

  11. Design and development of grazing incidence x-ray mirrors (United States)

    Zuo, Fuchang; Mei, Zhiwu; Ma, Tao; Deng, Loulou; Shi, Yongqiang; Li, Liansheng


    X-ray pulsar navigation has attracted extensive attentions from academy and engineering domains. The navigation accuracy is can be enhanced through design of X-ray mirrors to focus X-rays to a small detector. The Wolter-I optics, originally proposed based on a paraboloid mirror and a hyperboloid mirror for X-ray imaging, has long been widely developed and employed in X-ray observatory. Some differences, however, remain in the requirements on optics between astronomical X-ray observation and pulsar navigation. The simplified Wolter-I optics, providing single reflection by a paraboloid mirror, is more suitable for pulsar navigation. In this paper, therefore, the grazing incidence X-ray mirror was designed further based on our previous work, with focus on the reflectivity, effective area, angular resolution and baffles. To evaluate the performance of the manufactured mirror, the surface roughness and reflectivity were tested. The test results show that the grazing incidence mirror meets the design specifications. On the basis of this, the reflectivity of the mirror in the working bandwidth was extrapolated to evaluate the focusing ability of the mirror when it works together with the detector. The purpose of our current work to design and develop a prototype mirror was realized. It can lay a foundation and provide guidance for the development of multilayer nested X-ray mirror with larger effective area.

  12. Detecting Terrorism Incidence Type from News Summary

    DEFF Research Database (Denmark)

    Nizamani, Sarwat; Memon, Nasrullah


    The paper presents the experiments to detect terrorism incidence type from news summary data. We have applied classification techniques on news summary data to analyze the incidence and detect the type of incidence. A number of experiments are conducted using various classification algorithms...... and results show that a simple decision tree classifier can learn incidence type with satisfactory results from news data....

  13. Acousto-optic-assisted diffuse optical tomography

    NARCIS (Netherlands)

    Bratchenia, A.; Molenaar, Robert; van Leeuwen, Ton; Kooyman, R.P.H.


    We introduce and experimentally demonstrate acousto-optic-assisted diffuse optical tomography (DOT) using a holography-based acousto-optic setup. The method is based on probing a scattering medium with a localized acoustical modulation of the phase of the scattered light. The optical properties of


    NARCIS (Netherlands)

    Meijer, E.W.; Feringa, B.L.


    Chirality in molecular opto-electronics is limited sofar to the use of optically active liquid crystals and a number of optical phenomena are related to the helical macroscopic structure obtained by using one enantiomer, only. In this paper, the use of chirality in nonlinear optics and optical

  15. Partial scram incident in FBTR

    International Nuclear Information System (INIS)

    Usha, S.; Pillai, C.P.; Muralikrishna, G.


    Evaluation of a partial scram incident occurred at the Fast Breeder Test Reactor at Kalpakkam was carried out. Based on the observations of the experiments it was ascertained that the nonpersistant order was due to superimposed noise component on the channel that was close to the threshold and had resulted in intermittent supply to electro-magnetic (EM) coils. Owing to a larger discharge time and a smaller charge time, the EM coils got progressively discharged. It was confirmed that during the incident, partial scram took place since the charging and discharging patterns of the EM coils are dissimilar and EM coils of rods A, E and F had discharged faster than others for noise component of a particular duty cycle. However, nonlatching of scram order was because of the fact that noise pulse duration was less than latching time. (author)

  16. Dissociative Tendencies and Traffic Incidents

    Directory of Open Access Journals (Sweden)

    Valle, Virginia


    Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

  17. Incidents malignant neoplasias maxillofacial area. (United States)

    Goiato, Marcelo Coelho; Haddad, Marcela Filié; dos Santos, Daniela Micheline; Pesqueira, Aldiéres Alves; Filho, Humberto Gennari; Pellizzer, Eduardo Piza


    Cancer is regarded as abnormal cellular multiplication; it is not controlled by the organism, and its cells present a differentiated DNA. Initially, the disease does not show clinical signs, but it can be diagnosed by laboratory examinations. When tumors are present in the maxillofacial area, the carrier can lose structures in this area, resulting to the carrier's social environment exclusion. This article aims to show incidences and causes of malignant neoplasias in the maxillofacial area.

  18. [Familial incidence of Crohn disease]. (United States)

    Bürger, L; Karoff, C; Wagner, H


    This study reports about the frequent incidence of Crohn's disease in four families. This evidence in confirmed by literature. Relatives of patients with Crohn's disease are ten times more likely to suffer from that disease than those of healthy families. Familial accumulation of Crohn's disease can possibly be explained by genetic factors. Other factors like autoimmunological processes, infections, overnutrition and deficient composition of alimentation with refined carbohydrates might start Crohn's diseases in these families.

  19. Quantum Optics

    CERN Document Server

    Garrison, J C


    Quantum optics, i.e. the interaction of individual photons with matter, began with the discoveries of Planck and Einstein, but in recent years it has expanded beyond pure physics to become an important driving force for technological innovation. This book serves the broader readership growing out of this development by starting with an elementary description of the underlying physics and then building up a more advanced treatment. The reader is led from the quantum theory of thesimple harmonic oscillator to the application of entangled states to quantum information processing. An equally impor

  20. Incidence of respiratory distress syndrome

    International Nuclear Information System (INIS)

    Ghafoor, T.; Mahmud, S.; Ali, S.; Dogar, S.A.


    Objective: To determine the incidence of respiratory distress syndrome (RDS) in hospital born babies. Subjects and Methods: All live born infants delivered at the hospital and who fulfilled the diagnostic criteria of respiratory distress syndrome (RDS) were included in the study. Results: Ninety-four neonates developed RDS. Out of these, 88 (93.61%) were preterm and 06 (6.38%) were term infants. There was a male preponderance (65.95%). RDS was documented in 1.72% of total live births. 37.28% of preterm and 0.11% of term neonates born at the hospital. The incidence of RDS was 100% at 26 or less weeks of gestation, 57.14% at 32 weeks, and 3.70% at 36 weeks. The mortality with RDS was 41 (43.61%). Conclusion: RDS is the commonest cause of respiratory distress in the newborn, particularly, in preterm infants. It carries a high mortality rate and the incidence is more than that documented in the Western world. (author)

  1. [Skin cancer incidence in Zacatecas]. (United States)

    Pinedo-Vega, José Luis; Castañeda-López, Rosalba; Dávila-Rangel, J Ignacio; Mireles-García, Fernando; Ríos-Martínez, Carlos; López-Saucedo, Adrián


    Skin cancer is the most frequent cancer related to ultraviolet radiation. The aim was to estimate the incidence of skin cancer type, melanoma and non-melanoma in Zacatecas, Mexico. An epidemiological study was carried out during the period from 2008 to 2012. The data were obtained from the Instituto Mexicano del Seguro Social (IMSS), Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado (ISSSTE), Secretaría de Salud de Zacatecas (SSZ) and a private source, the Centro Médico Alameda. The incidence and the global prevalence were estimated. We studied 958 skin cancer cases, histopathologically confirmed. The cases were distributed as: 63.6 % basal cell carcinomas, 25.8 % squamous cell carcinomas, and 10.6 % melanoma. Significantly higher proportions were observed in women in the basal cell carcinomas (60.4 %) and squamous cell carcinomas (53.4 %). However, in the case of melanoma, the major proportion was observed in men (55.9 %). The more frequent skin cancer location was the face and for basal cell carcinoma was the nose (53 %); for squamous cell carcinomas were the lips (36 %), and for melanoma it was also the nose (40 %). The skin cancer incidence was estimated in 20 cases for each 100 000 inhabitants. Linear regression analysis showed that the skin cancer is increasing at an annual rate of 10.5 %. The anatomical location indicates that solar UV radiation is a risk factor, since the face is the zone with major exposure to solar radiation.

  2. Global phenomenological and microscopic optical model potentials for alpha (United States)

    Guo, Hairui; Su, Xinwu; Liang, Haiying; Xu, Yongli; Han, Yinlu; Shen, Qingbiao


    The global phenomenological and microscopic optical model potentials for alpha with the incident energy up to 400 MeV are obtained. The global phenomenological optical model potential is extracted by simultaneously fitting the experimental data of total reaction cross sections and elastic scattering angular distributions in the mass range of target nuclei 20 ≤ A ≤ 209. The microscopic optical model potential is obtained by the Green function method through nuclear matter approximation and local density approximation based on the effective Skyrme nucleon-nucleon interaction. Both optical model potentials are used to calculate the reaction cross sections and elastic scattering angular distributions for the target nuclei in the mass range 12 ≤ A ≤ 209 at incident alpha energies up to 400 MeV. The calculated results are compared with the experimental data, and the calculated results by phenomenological and microscopic optical model potentials are also compared with each other.

  3. Global phenomenological and microscopic optical model potentials for alpha

    Directory of Open Access Journals (Sweden)

    Guo Hairui


    Full Text Available The global phenomenological and microscopic optical model potentials for alpha with the incident energy up to 400 MeV are obtained. The global phenomenological optical model potential is extracted by simultaneously fitting the experimental data of total reaction cross sections and elastic scattering angular distributions in the mass range of target nuclei 20 ≤ A ≤ 209. The microscopic optical model potential is obtained by the Green function method through nuclear matter approximation and local density approximation based on the effective Skyrme nucleon-nucleon interaction. Both optical model potentials are used to calculate the reaction cross sections and elastic scattering angular distributions for the target nuclei in the mass range 12 ≤ A ≤ 209 at incident alpha energies up to 400 MeV. The calculated results are compared with the experimental data, and the calculated results by phenomenological and microscopic optical model potentials are also compared with each other.

  4. EDITORIAL: Optical orientation Optical orientation (United States)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried


    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  5. Imaging and steering an optical wireless nanoantenna link. (United States)

    Dregely, Daniel; Lindfors, Klas; Lippitz, Markus; Engheta, Nader; Totzeck, Michael; Giessen, Harald


    Optical nanoantennas tailor the transmission and reception of optical signals. Owing to their capacity to control the direction and angular distribution of optical radiation over a broad spectral range, nanoantennas are promising components for optical communication in nanocircuits. Here we measure wireless optical power transfer between plasmonic nanoantennas in the far-field and demonstrate changeable signal routing to different nanoscopic receivers via beamsteering. We image the radiation pattern of single-optical nanoantennas using a photoluminescence technique, which allows mapping of the unperturbed intensity distribution around plasmonic structures. We quantify the distance dependence of the power transmission between transmitter and receiver by deterministically positioning nanoscopic fluorescent receivers around the transmitting nanoantenna. By adjusting the wavefront of the optical field incident on the transmitter, we achieve directional control of the transmitted radiation over a broad range of 29°. This enables wireless power transfer from one transmitter to different receivers.

  6. Development of metrology instruments for grazing incidence mirrors

    International Nuclear Information System (INIS)

    Takacs, P.Z.; Church, E.L.; Qian, Shi-nan; Liu, Wuming


    The effective utilization of synchrotron radiation (SR) from high-brightness sources requires the use of optical components with very smooth surfaces and extremely precise shapes. Most manufacturers are not capable of measuring the figure and finish quality of the aspheric optics required for use in grazing incidence beam lines. Over the past several years we have developed measurement techniques and metrology instrumentation that have allowed us to measure the surface profile and roughness of large cylinder optics, up to one meter in length. Based on our measurements and feedback, manufacturers have been able to advance the state-of-the-art in mirror fabrication and are now able to produce acceptable components. Our analysis techniques enable designers to write meaningful specifications and predict the performance of real surfaces in their particular beamline configurations. Commercial instruments are now available for measuring surface microroughness with spatial periods smaller than about one millimeter. No commercial instruments are available for measuring the surface figure on cylindrical aspheres over long spatial periods, from one millimeter up to one meter. For that reason we developed a Long Trace Profiler (LTP) that measures surface profile over the long period range in a non-contact manner to extremely high accuracy. Examples of measured surfaces and data analysis techniques will be discussed, and limitations on the quality of optical surfaces related to intrinsic material properties will also be discussed. 15 refs., 14 figs., 2 tabs

  7. Optimal design and fabrication method for antireflection coatings for P-polarized 193 nm laser beam at large angles of incidence (68°-74°). (United States)

    Jin, Jingcheng; Jin, Chunshui; Li, Chun; Deng, Wenyuan; Chang, Yanhe


    Most of the optical axes in modern systems are bent for optomechanical considerations. Antireflection (AR) coatings for polarized light at oblique incidence are widely used in optical surfaces like prisms or multiform lenses to suppress undesirable reflections. The optimal design and fabrication method for AR coatings with large-angle range (68°-74°) for a P-polarized 193 nm laser beam is discussed in detail. Experimental results showed that after coating, the reflection loss of a P-polarized laser beam at large angles of incidence on the optical surfaces is reduced dramatically, which could greatly improve the output efficiency of the optical components in the deep ultraviolet vacuum range.

  8. Nucleon relativistic phenomenological and microscopic optical potential

    International Nuclear Information System (INIS)

    Shen Qingbiao; Feng Dachun; Zhuo Yizhong


    In this talk, both the phenomenological and microscopic nucleon relativistic optical potentials are presented. The global neutron relativistic phenomenological optical potential (RPOP) based on the available experimental data for various nuclei ranging from C to U with incident energies En=20-1000 MeV has been obtained through automatic search of the best parameters by computer. Then the nucleon relativistic microscopic optical potential (RMOP) is studied by utilizing effective lagrangian based on popular Walecka model. Through comparison between the theoretical results and experimental data we have shed some insight into both the RMOP and RPOP. We have concluded that both the phenomenological and microscopic relativistic optical potentials proposed here can be extensively used for intermediate energy nucleon data evaluation. Further improvement concerning how to combine the phenomenological potential with the microscopic one in order to reduce the number of free parameters appearing in RPOP is suggested. (author). 33 refs, 24 figs

  9. Free-space wavelength-multiplexed optical scanner. (United States)

    Yaqoob, Z; Rizvi, A A; Riza, N A


    A wavelength-multiplexed optical scanning scheme is proposed for deflecting a free-space optical beam by selection of the wavelength of the light incident on a wavelength-dispersive optical element. With fast tunable lasers or optical filters, this scanner features microsecond domain scan setting speeds and large- diameter apertures of several centimeters or more for subdegree angular scans. Analysis performed indicates an optimum scan range for a given diffraction order and grating period. Limitations include beam-spreading effects based on the varying scanner aperture sizes and the instantaneous information bandwidth of the data-carrying laser beam.

  10. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong


    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  11. Oblique incidence of semi-guided waves on rectangular slab waveguide discontinuities: A vectorial QUEP solver

    NARCIS (Netherlands)

    Hammer, Manfred


    The incidence of thin-film-guided, in-plane unguided waves at oblique angles on straight discontinuities of dielectric slab waveguides, an early problem of integrated optics, is being re-considered. The 3-D frequency domain Maxwell equations reduce to a parametrized inhomogeneous vectorial problem

  12. Holographic Optical Data Storage (United States)

    Timucin, Dogan A.; Downie, John D.; Norvig, Peter (Technical Monitor)


    Although the basic idea may be traced back to the earlier X-ray diffraction studies of Sir W. L. Bragg, the holographic method as we know it was invented by D. Gabor in 1948 as a two-step lensless imaging technique to enhance the resolution of electron microscopy, for which he received the 1971 Nobel Prize in physics. The distinctive feature of holography is the recording of the object phase variations that carry the depth information, which is lost in conventional photography where only the intensity (= squared amplitude) distribution of an object is captured. Since all photosensitive media necessarily respond to the intensity incident upon them, an ingenious way had to be found to convert object phase into intensity variations, and Gabor achieved this by introducing a coherent reference wave along with the object wave during exposure. Gabor's in-line recording scheme, however, required the object in question to be largely transmissive, and could provide only marginal image quality due to unwanted terms simultaneously reconstructed along with the desired wavefront. Further handicapped by the lack of a strong coherent light source, optical holography thus seemed fated to remain just another scientific curiosity, until the field was revolutionized in the early 1960s by some major breakthroughs: the proposition and demonstration of the laser principle, the introduction of off-axis holography, and the invention of volume holography. Consequently, the remainder of that decade saw an exponential growth in research on theory, practice, and applications of holography. Today, holography not only boasts a wide variety of scientific and technical applications (e.g., holographic interferometry for strain, vibration, and flow analysis, microscopy and high-resolution imagery, imaging through distorting media, optical interconnects, holographic optical elements, optical neural networks, three-dimensional displays, data storage, etc.), but has become a prominent am advertising

  13. Data on incident solar energy (United States)

    Thekaekara, M. P.


    Instrumentation for solar irradiance monitoring, and radiation scales are discussed in a survey of incident solar energy data. The absolute accuracy and intrinsic reliability of the values of the solar constant and zero air mass solar spectrum proposed by the Institute of Environmental Sciences as an ASTM standard are evaluated. Extraterrestrial observations are used for deriving solar irradiance data at ground level for widely varying atmospheric parameters, with special reference to air pollution. The effects of diffuse sky radiance and those of varying slopes of the solar energy collecting surface are examined. Average values of solar energy available at different locations in the United States are included.

  14. Grazing incidence diffraction : A review

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, B. [LTPCM, ENSEEG. St. Martin d`Heres. (France)


    Different Grazing Incidence Diffraction (GID) methods for the analysis of thin films and multilayer structures are reviewed in three sections: the reflectivity is developed in the first one, which includes the non-specular diffuse scattering. The second one is devoted to the extremely asymmetric Bragg diffraction and the third one to the in-plane Bragg diffraction. Analytical formulations of the scattered intensities are developed for each geometry, in the framework of the kinetical analysis as well as the dynamical theory. Experimental examples are given to illustrate the quantitative possibility of the GID techniques.

  15. USFA NFIRS 2013 Fire Incident & Cause Data (United States)

    Department of Homeland Security — The 2013 Fire Causes & Incident data was provided by the U.S. Fire Administration’s (USFA) National Fire Data Center’s (NFDC’s) National Fire Incident Reporting...

  16. Increasing incidence of diabetes after gestational diabetes

    DEFF Research Database (Denmark)

    Lauenborg, Jeannet; Hansen, Torben; Jensen, Dorte Møller


    To study the incidence of diabetes among women with previous diet-treated gestational diabetes mellitus (GDM) in the light of the general increasing incidence of overweight and diabetes and to identify risk factors for the development of diabetes....

  17. Ionospheric Oblique Incidence Soundings by Satellites (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The oblique incidence sweep-frequency ionospheric sounding technique uses the same principle of operation as the vertical incidence sounder. The primary difference...

  18. Increasing incidence of diabetes after gestational diabetes

    DEFF Research Database (Denmark)

    Lauenborg, Jeannet; Hansen, Torben; Jensen, Dorte Møller


    To study the incidence of diabetes among women with previous diet-treated gestational diabetes mellitus (GDM) in the light of the general increasing incidence of overweight and diabetes and to identify risk factors for the development of diabetes.......To study the incidence of diabetes among women with previous diet-treated gestational diabetes mellitus (GDM) in the light of the general increasing incidence of overweight and diabetes and to identify risk factors for the development of diabetes....

  19. Quantum optics for experimentalists

    CERN Document Server

    Ou, Zhe-Yu Jeff


    This book on quantum optics is from the point of view of an experimentalist. It approaches the theory of quantum optics with the language of optical modes of classical wave theory, with which experimentalists are most familiar.

  20. Introduction to biomedical optics

    CERN Document Server

    Splinter, Robert


    GENERAL BIOMEDICAL OPTICS THEORYIntroduction to the Use of Light for Diagnostic and Therapeutic ModalitiesWhat Is Biomedical Optics?Biomedical Optics TimelineElementary Optical DiscoveriesHistorical Events in Therapeutic and Diagnostic Use of LightLight SourcesCurrent State of the ArtSummaryAdditional ReadingProblemsReview of Optical Principles: Fundamental Electromagnetic Theory and Description of Light SourcesDefinitions in OpticsKirchhoff's Laws of RadiationElectromagnetic Wave TheoryLight SourcesApplications of Various LasersSummaryAdditional ReadingProblemsReview of Optical Principles: Classical OpticsGeometrical OpticsOther Optical PrinciplesQuantum PhysicsGaussian OpticsSummaryAdditional ReadingProblemsReview of Optical Interaction PropertiesAbsorption and ScatteringSummaryAdditional ReadingProblemsLight-Tissue Interaction VariablesLaser VariablesTissue VariablesLight Transportation TheoryLight Propagation under Dominant AbsorptionSummaryNomenclatureAdditional ReadingProblemsLight-Tissue Interaction Th...

  1. Coding for optical channels

    CERN Document Server

    Djordjevic, Ivan; Vasic, Bane


    This unique book provides a coherent and comprehensive introduction to the fundamentals of optical communications, signal processing and coding for optical channels. It is the first to integrate the fundamentals of coding theory and optical communication.

  2. Optical absorption in a thin nickel wire


    INAGAKI, Takashi; Goudonnet, J.P.; ARAKAWA, E.T.


    Absorption of a 633-nm phonton in a cylindrical nickel wire with diameter 13 m was measured by a photoacoustic method as a function of angle of phonton incidence . A good photoacoustic signal was obtained with a 6-m W He-Ne laser as a light source without employing focusing optics. The absorption measured for p-polarized phontons was found to be in good agreement with geometrical optics calculation. For s-polarized light, however, significant excess absorption was found for >35.

  3. Self-Induced Backaction Optical Pulling Force (United States)

    Zhu, Tongtong; Cao, Yongyin; Wang, Lin; Nie, Zhongquan; Cao, Tun; Sun, Fangkui; Jiang, Zehui; Nieto-Vesperinas, Manuel; Liu, Yongmin; Qiu, Cheng-Wei; Ding, Weiqiang


    We achieve long-range and continuous optical pulling in a periodic photonic crystal background, which supports a unique Bloch mode with the self-collimation effect. Most interestingly, the pulling force reported here is mainly contributed by the intensity gradient force originating from the self-induced backaction of the object to the self-collimation mode. This force is sharply distinguished from the widely held conception of optical tractor beams based on the scattering force. Also, this pulling force is insensitive to the angle of incidence and can pull multiple objects simultaneously.

  4. Parkinson's disease incidence: magnitude, comparability, time trends. (United States)

    de Pedro-Cuesta, J; Stawiarz, L


    In this study, we reviewed incidence surveys of Parkinson's Disease (PD) from all over the world, published during the period 1945-1989, using reported quality criteria. In addition, we compared age-specific PD incidences from selected observations by stratified analysis. Crude incidences were described for 11 populations, and age-specific incidences for three of them: Iceland, Rochester (Minn, USA), and Turku (Finland). Effect modification by age was detected: a) by comparing incidences by age at diagnosis with incidence by age at clinical disease onset; and b) when only data on onset of disease was computed. For disease onsets, the incidences in Rochester for the period 1955-1966, and in Turku (Finland) during the interval 1968-1970, were lower than that in Iceland for the period 1958-1960: RR = 0.58 95% CI (0.41, 0.83), and RR = 0.67 95% CI (0.51, 0.87), respectively. For the Rochester population aged 40-69 years, a statistically significant 56% decrease in the incidences of Parkinsonism onsets during the period 1945-1966 was found. Validity problems in comparing PD incidences and the role of PD underdiagnosis were emphasized. We concluded that: a) stratified analysis is more suitable than standardization when comparing incidences for etiological purposes; b) the incidence of PD was highest in Iceland; and c) in Rochester, PD incidence under the age of 70 decreased with time.

  5. Tunable laser optics

    CERN Document Server

    Duarte, FJ


    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  6. Metrology of reflection optics for synchrotron radiation

    International Nuclear Information System (INIS)

    Takacs, P.Z.


    Recent years have seen an almost explosive growth in the number of beam lines on new and existing synchrotron radiation facilities throughout the world. The need for optical components to utilize the unique characteristics of synchrotron radiation has increased accordingly. Unfortunately, the technology to manufacture and measure the large, smooth, exotic optical surfaces required to focus and steer the synchrotron radiation beam has not progressed as rapidly as the operational demands on these components. Most companies do not wish to become involved with a project that requires producing a single, very expensive, aspheric optic with surface roughness and figure tolerances that are beyond their capabilities to measure. This paper will review some of the experiences of the National Synchrotron Light Source in procuring grazing incidence optical components over the past several years. We will review the specification process - how it is related to the function of the optic, and how it relates to the metrology available during the manufacturing process and after delivery to the user's laboratory. We will also discuss practical aspects of our experience with new technologies, such as single point diamond turning of metal mirrors and the use of SiC as a mirror material. Recent advances in metrology instrumentation have the potential to move the measurement of surface figure and finish from the research laboratory into the optical shop, which should stimulate growth and interest in the manufacturing of optics to meet the needs of the synchrotron radiation user community

  7. Optical Remote Sensing Laboratory (United States)

    Federal Laboratory Consortium — The Optical Remote Sensing Laboratory deploys rugged, cutting-edge electro-optical instrumentation for the collection of various event signatures, with expertise in...

  8. Intelligent Optics Laboratory (United States)

    Federal Laboratory Consortium — The Intelligent Optics Laboratory supports sophisticated investigations on adaptive and nonlinear optics; advancedimaging and image processing; ground-to-ground and...

  9. Fibre-optic communications

    CERN Document Server

    Lecoy, Pierre


    This book describes in a comprehensive manner the components and systems of fiber optic communications and networks. The first section explains the theory of multimode and single-mode fibers, then the technological features, including manufacturing, cabling, and connecting. The second section describes the various components (passive and active optical components, integrated optics, opto-electronic transmitters and receivers, and optical amplifiers) used in fiber optic systems. Finally, the optical transmission system design is explained, and applications to optical networks and fiber optic se

  10. Analysis of the enhanced coupling efficiency for different profile curves of special optical taper (United States)

    Gao, Fei-long; Fu, Xing-hu; Fu, Guang-wei; Bi, Wei-hong


    For enhancing the coupling efficiency between the beam and the photodiode, a special optical taper is proposed for receiving optical signal. Based on the circular symmetric structure of special optical taper, the profile curve equations of it are deduced, including the trigonometric function type, parabolic type and exponential type. Moreover, the coupling efficiencies for special optical tapers with different profile curves are studied. The relationships of incident position, incident angle and coupling efficiency are analyzed. Finally, the comparison of coupling efficiency analytical results is also given.

  11. On the vergence field in the north Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Varadachari, V.V.R.; Sharma, G.S.

    be prevalent during the period January to August while sinking may be prevalent during the remaining period of the year. This is in agreement with the earlier findings by the authors and others on upwelling on the east coast of India as deduced from temperature...

  12. Light vergence detection in monocular and monochromatic accommodation


    Del Águila Carrasco, Antonio Jesús


    El ojo proyecta información desde el mundo tridimensional a la retina, la cual es una superficie bidimensional. Por este motivo, teóricamente sólo objetos que se encuentren en el plano conjugado a la retina pueden ser enfocados de forma correcta y, por tanto, objetos que se encuentren por delante o por detrás del plano conjugado, serán percibidos como imágenes borrosas. Por suerte, la acomodación ocular permite al ojo joven ver objetos situados a diferentes distancias de forma nítida. Este si...


    Directory of Open Access Journals (Sweden)

    K. Rojaramani Kumbha


    Full Text Available Advanced Technology and early detection of disease by recent improvements in investigation modalities lead to decreased incidents of amputations while Road Traffic Accidents (RTA increase. Furthermore, it leads to variation and decreased morbidity, mortality and accidents (crush injuries, and better equipped and trained staff, specialist services, diabetic food, rehabilitation centres, and giving good support physically and psychologically for Amputated patients. OBJECTIVE To know incidence rates of Emergency Amputation who attended causality with advanced disease and severe Trauma. METHODOLOGY The study is done over a period of one year i.e. between June 2015 to June 2016 who attended causality with advanced and severe disease affecting the limbs either due to diabetes, trauma or vascular diseases. RESULTS During one-year period, total 6,371 patients attended for general surgery OP. In those, 187 patients needed emergency surgery which included both major and minor operations. Among those, 81 patients were amputated. CONCLUSION As per our available records and observation, even though there is increased literacy and access to advanced technology, there is still increased incidence of patients undergoing amputations due to diseases. Therefore, there is a need to improve awareness and importance of early detection of diabetes, hazards of smoking, and regular general health checkups for patients at root level. With that we can treat diabetes and/or any disease in time. So there must be awareness in peripheral health staff i.e. PHC, subcentres, and community health centres about early detection of disease which in turn improves the quality of life of the patient. Due to diabetes slight injury to the glucose laden tissue may cause chronic infection and ulcer formation.(1 The tumours are seen commonly in the age group of 20-40 years after bone fusion, bones affected commonly are those around the knee (lower end of knee, upper end of tibia. A lytic

  14. Responding to a biological incident

    Energy Technology Data Exchange (ETDEWEB)

    Campagna, P.R. [U.S. Environmental Response Team, Office of Superfund Remediation and Technology Innovation, Edison, NJ (United States)


    The U.S. Environmental Protection Agency's Environmental Response Team (ERT) was established in October 1978 to provide technical assistance to a variety of governmental agencies in the area of environmental emergency issues such as chemical spills, uncontrolled hazardous waste site and terrorist incidents. This paper describes responses to a biological incident that occurred on July 29 2004, when the United States Department of Agriculture (USDA) received an anonymous e-mail identifying 3 containers on board the M/V Rio Puelo, one of which was said to contain a harmful biological substance. The containers were part of a 5 container shipment of Argentinian lemons bound for Canada. The vessel had a total of 2204 containers, of which 260 were loaded at the same port as the lemons. The containers were to be off-loaded at the Port of Newark and transported via truck to Canada. The federal On-Scene Coordinator (OSC) was responsible for managing this incident, as well as assessing the creditability of the threat. In accordance with federal authorities under the Public Water Safety Act, the Captain of the Port of New York ordered the vessel to anchor off shore. A tactical security operations team was dispatched to assess vessel security. It was determined that none of the crew, who had been exposed to the potential agent 10 days earlier, had shown any symptoms of biological warfare agents. A multi-agency unified command was set up, consisting of state, federal and local agencies. Various options were evaluated, including treatment of the containers on board due to the possibility of a dispersal device which could cause wide-spread contamination; the off loading and disposal of the cargo into the sea; and off loading of containers on shore with subsequent treatment. The following safety precautions were taken: cooling units were shut off 48 hours before sailing; the vents were sealed and closed; and the drains were plugged. At the port, trained dogs were used, and

  15. Nested Focusing Optics for Compact Neutron Sources (United States)

    Nabors, Sammy A.


    NASA's Marshall Space Flight Center, the Massachusetts Institute of Technology (MIT), and the University of Alabama Huntsville (UAH) have developed novel neutron grazing incidence optics for use with small-scale portable neutron generators. The technology was developed to enable the use of commercially available neutron generators for applications requiring high flux densities, including high performance imaging and analysis. Nested grazing incidence mirror optics, with high collection efficiency, are used to produce divergent, parallel, or convergent neutron beams. Ray tracing simulations of the system (with source-object separation of 10m for 5 meV neutrons) show nearly an order of magnitude neutron flux increase on a 1-mm diameter object. The technology is a result of joint development efforts between NASA and MIT researchers seeking to maximize neutron flux from diffuse sources for imaging and testing applications.

  16. Incident-response monitoring technologies for aircraft cabin air quality (United States)

    Magoha, Paul W.

    from BAS tests by optical particle counter (OPC) revealed lognormal distributions with the mean (range) of geometric mass mean diameter (GMMD) = 0.41 (0.39, 0.45) microm and geometric standard deviation (GSD), sigma g = 1.92 (1.87, 1.98). FESEM/EDS and NAA techniques found a wide range of elements on filters, and further investigations of used filters are recommended using these techniques. The protocols for air and filter sampling and GC/MS analysis used in this study will increase the options available for detecting jet engine oil on cabin air filters. Such criteria could support policy development for compliance with cabin air quality standards during incidents.

  17. Incidence of sialolithiasis in Denmark

    DEFF Research Database (Denmark)

    Schrøder, Stine Attrup; Andersson, Mikael; Wohlfahrt, Jan


    Sialolithiasis is a frequent disorder affecting the salivary glands. The incidence rate (IR) has been reported to be 2.9-5.5 per 100,000 person-years, but all previous studies have been based on selected hospital data. In this study, we conducted a population-based study evaluating the IR...... of sialolithiasis and the IR variation according to age, gender and geography in Denmark. We included data from hospitals as well as from private ear, nose and throat (ENT) clinics. The study was based on registry data on all sialolithiasis cases in Denmark between 2003 and 2009 extracted from the Danish National...... Patient Registry (hospital cohort) and the Danish Regions Centre for Healthcare Statistics (private ENT clinic cohort). To validate the diagnosis, the proportion of visually confirmed cases was estimated based on patient records from subsamples of the two cohorts. The IR was 7.27 and 14.10 per 100...

  18. An introduction to incidence geometry

    CERN Document Server

    De Bruyn, Bart


    This book gives an introduction to the field of Incidence Geometry by discussing the basic families of point-line geometries and introducing some of the mathematical techniques that are essential for their study. The families of geometries covered in this book include among others the generalized polygons, near polygons, polar spaces, dual polar spaces and designs. Also the various relationships between these geometries are investigated. Ovals and ovoids of projective spaces are studied and some applications to particular geometries will be given. A separate chapter introduces the necessary mathematical tools and techniques from graph theory. This chapter itself can be regarded as a self-contained introduction to strongly regular and distance-regular graphs. This book is essentially self-contained, only assuming the knowledge of basic notions from (linear) algebra and projective and affine geometry. Almost all theorems are accompanied with proofs and a list of exercises with full solutions is given at the end...


    CERN Multimedia


    On 27 June 2000 three specialists were investigating a problem with the extraction electrode of the high-resolution separator (HRS) in Isolde. Whilst using an endoscope in order to have a closer look at the interior, they came into contact with radioactive dust and became contaminated. The level of contamination was low and the radiation dose received by the 3 persons was far below the effective dose limit given in the CERN Radiation Safety Manual and in the regulations of the Host States.According to the usual procedure, the Director General has set up a Fact-Finding Group and an Accident Board in order to advise him on the steps and decisions tobe taken following this incident and in particular to avoid a recurrence.

  20. The Jarvis gas release incident

    International Nuclear Information System (INIS)

    Manocha, J.


    On 26 September, 1991, large volumes of natural gas were observed to be leaking from two water wells in the Town of Jarvis. Gas and water were being ejected from a drilled water well, at which a subsequent gas explosion occurred. Measurements of gas concentrations indicated levels far in excess of the lower flammability limit at several locations. Electrical power and natural gas services were cut off, and residents were evacuated. A state of emergency was declared, and gas was found to be flowing from water wells, around building foundations, and through other fractures in the ground. By 27 September the volumes of gas had reduced substantially, and by 30 September all residents had returned to their homes and the state of emergency was cancelled. The emergency response, possible pathways of natural gas into the aquifer, and public relations are discussed. It is felt that the likelihood of a similar incident occurring in the future is high. 11 figs

  1. Light Optics for Optical Stochastic Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Andorf, Matthew [NICADD, DeKalb; Lebedev, Valeri [Fermilab; Piot, Philippe [NICADD, DeKalb; Ruan, Jinhao [Fermilab


    In Optical Stochastic Cooling (OSC) radiation generated by a particle in a "pickup" undulator is amplified and transported to a downstream "kicker" undulator where it interacts with the same particle which radiated it. Fermilab plans to carry out both passive (no optical amplifier) and active (optical amplifier) tests of OSC at the Integrable Optics Test Accelerator (IOTA) currently in construction*. The performace of the optical system is analyzed with simulations in Synchrotron Radiation Workshop (SRW) accounting for the specific temporal and spectral properties of undulator radiation and being augmented to include dispersion of lens material.

  2. Scrutinizing incident reporting in anaesthesia: why is an incident perceived as critical?

    DEFF Research Database (Denmark)

    Maaløe, R; la Cour, M; Hansen, A


    The purpose of the present study was to measure the incidence and type of incidents that occurred in relation to anaesthesia and surgery during a 1-year period in six Danish hospitals. Furthermore, we wanted to identify risk factors for incidents, as well as risk factors for incidents being deemed...

  3. Structured interference force for enhanced optical trapping (Presentation Recording) (United States)

    Taylor, Michael A.; Waleed, Muhammad; Stilgoe, Alexander B.; Rubinsztein-Dunlop, Halina; Bowen, Warwick P.


    Interferometry can completely redirect light, providing the potential for exceptionally strong and controllable optical forces. When a beamsplitter combines two fields, the output power is directed via the relative phase between the incident fields. Since the phase changes with beamsplitter displacement, the interference force can be used to stably trap; with displacements as small as (λ/4n) able to completely redirect the light. The resulting change in optical momentum causes an opposing optical force. However, optical forces are most useful for trapping and manipulating small scattering particles. Optical scattering is not generally thought to allow efficient interference; essentially, it appears that small particles cannot act as beamsplitters. As such, optical traps have relied upon much weaker deflection-based forces. Here we show that efficient interference can be achieved by appropriately structuring the incident light. This relies on Mie scattering fringes to combine light which is incident from different incident angles. This results in a force, which we call the structured interference force, which offers order-of-magnitude higher trap stiffness over the usual Gaussian trap. We demonstrate structured interference force trapping (SIFT) of 10μm diameter silica spheres with a stiffness 20.1 times higher than is possible using Gaussian traps, while also increasing the measurement signal-to-noise ratio by two orders of magnitude. This is demonstrated using only phase control of the incident light, making the technique directly compatible with most existing holographic optical traps. These results are highly relevant to many applications, including cellular manipulation, fluid dynamics, micro-robotics, and tests of fundamental physics.

  4. A population-based prospective study of optic neuritis

    DEFF Research Database (Denmark)

    Soelberg, K; Jarius, S; Skejoe, Hanne Pernille Bro


    BACKGROUND: Optic neuritis (ON) is often associated with multiple sclerosis (MS). Early diagnosis is critical to optimal patient management. OBJECTIVE: To estimate the incidence of acute ON and the rates of conversion to MS and antibody-mediated ON. METHOD: Population-based prospective study......: The prospective incidence of ON was estimated. MRI enabled a diagnosis of MS in a subgroup of patients. Antibody-mediated ON with specificity for MOG was detected in 4% of cases....

  5. Finite-Difference Time-Domain Integration of Ultrafast Dynamics in Optical Resonators

    National Research Council Canada - National Science Library

    Basinger, Scott


    .... The resonator is a Fabry-Perot cavity that has a nonlinear absorbing material in the center. When an optical field of the resonant frequency is incident upon the cavity, the field intensity increases inside the cavity...

  6. High-Resolution Detector for At-Wavelength Metrology of X-Ray Optics, Phase I (United States)

    National Aeronautics and Space Administration — Since the launch of the first X-ray focusing telescope in 1963, the development of grazing incidence X-ray optics has been crucial to the development of the field of...

  7. High-Resolution Detector for At-Wavelength Metrology of X-Ray Optics, Phase II (United States)

    National Aeronautics and Space Administration — Since the launch of the first X-ray focusing telescope in 1963, the development of grazing incidence X-ray optics has been crucial to the development of the field of...

  8. High-Resolution Detector for At-Wavelength Metrology of X-Ray Optics Project (United States)

    National Aeronautics and Space Administration — Since the launch of the first X-ray focusing telescope in 1963, the development of grazing incidence X-ray optics has been crucial to the development of the field of...

  9. Optic Nerve Pit (United States)

    ... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Optic Nerve Pit What is optic nerve pit? An optic nerve pit is a ... may be seen in both eyes. How is optic pit diagnosed? If the pit is not affecting ...

  10. Optical image encryption topology. (United States)

    Yong-Liang, Xiao; Xin, Zhou; Qiong-Hua, Wang; Sheng, Yuan; Yao-Yao, Chen


    Optical image encryption topology is proposed based on the principle of random-phase encoding. Various encryption topological units, involving peer-to-peer, ring, star, and tree topologies, can be realized by an optical 6f system. These topological units can be interconnected to constitute an optical image encryption network. The encryption and decryption can be performed in both digital and optical methods.

  11. Optical force on diseased blood cells: Towards the optical sorting of biological matter

    KAUST Repository

    Gongora, J. S. Totero


    By employing a series of massively parallel ab-initio simulations, we study how optical forces act on biological matter subject to morphological disease. As a representative case study, we here consider the case of Plasmodium falciparum on red blood cells (RBC) illuminated by a monochromatic plane wave. Realistic parameters for the geometry and the refractive index are then taken from published experiments. In our theoretical campaign, we study the dependence of the optical force on the disease stage for different incident wavelengths. We show that optical forces change significantly with the disease, with amplitude variation in the hundreds of pN range. Our results open up new avenues for the design of new optical systems for the treatment of human disease. © 2015 Elsevier Ltd.

  12. Performing derivative and integral operations for optical waves with optical metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Cun-Li [College of Engineering, Nanjing Agriculture University, Nanjing Jiangsu, 210031 (China); College of Science, Nanjing Agriculture University, Nanjing Jiangsu, 210095 (China); Zhao, Zhi-Gang; Li, Xiao-Lin [College of Engineering, Nanjing Agriculture University, Nanjing Jiangsu, 210031 (China); Yang, Hong-Wei, E-mail: [College of Science, Nanjing Agriculture University, Nanjing Jiangsu, 210095 (China)


    The graded refractive index waveguides can perform Fourier transform for an optical wave. According to this characteristic, simpler optical metamaterials with three waveguides are theoretically proposed, in which all of the waveguides are materials with a positive refractive index. By selecting the appropriate refractive index and structure size, the theory and simulations demonstrated that these metamaterials can perform mathematical operations for the outline of incident optical waves, including the first-order derivative, second-order derivative and the integral. - Highlights: • The derivative and integral operations of optical waves are achieved with a simpler model. • Both negative and positive refractive index boast the same functions. • The mathematical operations can be implemented only by changing the refractive index of the intermediate material. • The results will greatly expand the possible applications, including photon computers, picture processing, video displays and data storage.

  13. Intensity-dependent nonlinear optical properties in a modulation-doped single quantum well

    International Nuclear Information System (INIS)

    Ungan, F.


    In the present work, the changes in the intersubband optical absorption coefficients and the refractive index in a modulation-doped quantum well have been investigated theoretically. Within the envelope function approach and the effective mass approximation, the electronic structure of the quantum well is calculated from the self-consistent numerical solution of the coupled Schroedinger-Poisson equations. The analytical expressions of optical properties are obtained by using the compact density-matrix approach. The numerical results GaAs/Al x Ga 1-x As are presented for typical modulation-doped quantum well system. The linear, third-order nonlinear and total absorption and refractive index changes depending on the doping concentration are investigated as a function of the incident optical intensity and structure parameters, such as quantum well width and stoichiometric ratio. The results show that the doping concentration, the structure parameters and the incident optical intensity have a great effect on the optical characteristics of these structures. - Highlights: → The doping concentration has a great effect on the optical characteristics of these structures. → The structure parameters have a great effect on the optical properties of these structures. → The total absorption coefficients reduced as the incident optical intensity increases. → The RICs reduced as the incident optical intensity increases.

  14. Optics for dummies

    CERN Document Server

    Duree, Galen C


    The easy way to shed light on Optics In general terms, optics is the science of light. More specifically, optics is a branch of physics that describes the behavior and properties of light?including visible, infrared, and ultraviolet?and the interaction of light with matter. Optics For Dummies gives you an approachable introduction to optical science, methods, and applications. You'll get plain-English explanations of the nature of light and optical effects; reflection, refraction, and diffraction; color dispersion; optical devices, industrial, medical, and military applicatio

  15. Adaptive optics in microscopy. (United States)

    Booth, Martin J


    The imaging properties of optical microscopes are often compromised by aberrations that reduce image resolution and contrast. Adaptive optics technology has been employed in various systems to correct these aberrations and restore performance. This has required various departures from the traditional adaptive optics schemes that are used in astronomy. This review discusses the sources of aberrations, their effects and their correction with adaptive optics, particularly in confocal and two-photon microscopes. Different methods of wavefront sensing, indirect aberration measurement and aberration correction devices are discussed. Applications of adaptive optics in the related areas of optical data storage, optical tweezers and micro/nanofabrication are also reviewed.

  16. Fiber optic connector (United States)

    Rajic, Slobodan; Muhs, Jeffrey D.


    A fiber optic connector and method for connecting composite materials within which optical fibers are imbedded. The fiber optic connector includes a capillary tube for receiving optical fibers at opposing ends. The method involves inserting a first optical fiber into the capillary tube and imbedding the unit in the end of a softened composite material. The capillary tube is injected with a coupling medium which subsequently solidifies. The composite material is machined to a desired configuration. An external optical fiber is then inserted into the capillary tube after fluidizing the coupling medium, whereby the optical fibers are coupled.

  17. Magneto-optical Kerr effect studies with classical electromagnetic theory (United States)

    Ma, Rui-Can; Gao, Ling-Ling; Zhang, Ting; Jin, Yi


    Employing the basic law of electromagnetic wave propagation with the constitutive relation of ideal ferromagnetic medium, the magneto-optical Kerr effect of linearly polarized plane wave on the surface of ideal ferromagnetic medium is studied. We also discuss the change law of the Kerr rotation angle with the incident angle and magnetic-field strength in detail, which can provide crucial information for the applications of the magneto-optical Kerr effect in many fields.

  18. Integrated optics technology study (United States)

    Chen, B.


    The materials and processes available for the fabrication of single mode integrated electrooptical components are described. Issues included in the study are: (1) host material and orientation, (2) waveguide formation, (3) optical loss mechanisms, (4) wavelength selection, (5) polarization effects and control, (6) laser to integrated optics coupling,(7) fiber optic waveguides to integrated optics coupling, (8) souces, (9) detectors. The best materials, technology and processes for fabrication of integrated optical components for communications and fiber gyro applications are recommended.

  19. Measurement of optical glasses

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.


    The possibilities of measurement of the optical glasses parameters needed in building optical devices especially in lasers devices are presented. In the first chapter the general features of the main optical glasses as well as the modalities of obtaining them are given. Chapter two defines the optical glass parameters, and the third chapter describes the measuring methods of the optical glass parameters. Finally, the conclusions which point out the utilization of this paper are presented. (author)

  20. Optical imaging and spectroscopy

    CERN Document Server

    Brady, David J


    An essential reference for optical sensor system design This is the first text to present an integrated view of the optical and mathematical analysis tools necessary to understand computational optical system design. It presents the foundations of computational optical sensor design with a focus entirely on digital imaging and spectroscopy. It systematically covers: Coded aperture and tomographic imaging Sampling and transformations in optical systems, including wavelets and generalized sampling techniques essential to digital system analysis Geometric, wave, and statis

  1. Cancer incidence among Danish seafarers

    DEFF Research Database (Denmark)

    Kærlev, Linda; Hansen, Johnny; Lyngbeck Hansen, Hans


    .19 to 1.32) for men and 1.07 (95% CI 0.95 to 1.20) for women. This was mainly due to an excess of cancer of the larynx, lung, tongue, mouth, pharynx, oesophagus, pancreas, kidney, urinary bladder, colon, and bone as well as skin melanomas among men (the three latter borderline significantly increased...... extensively in ships. The aim of this study was to study cancer morbidity among Danish seafarers in relation to type of ship and job title. METHODS: A cohort of all Danish seafarers during 1986-1999 (33,340 men; 11,291 women) registered by the Danish Maritime Authority with an employment history was linked...... with the nationwide Danish Cancer Registry and followed up for cancer until the end of 2002. The number of person years at risk was 517,518. Standardised incidence ratios (SIR) were estimated by use of the corresponding national rates. RESULTS: The SIR of all cancers combined was higher than expected: 1.26 (95% CI 1...

  2. Bronchoaspiration: incidence, consequences and management. (United States)

    Beck-Schimmer, Beatrice; Bonvini, John M


    Aspiration is defined as the inhalation of oropharyngeal or gastric contents into the lower respiratory tract. Upon injury, epithelial cells and alveolar macrophages secrete chemical mediators, attracting and activating neutrophils, which in turn release proteases and reactive oxygen species, degrading the alveolocapillary unit. Aspiration can lead to a range of diseases such as infectious pneumonia, chemical pneumonitis or respiratory distress syndrome with significant morbidity and mortality. It occurs in approximately 3-10 per 10 000 operations with an increased incidence in obstetric and paediatric anaesthesia. Patients are most at risk during induction of anaesthesia and extubation, in particular in emergency situations. The likelihood of significant aspiration can be reduced by fasting, pharmacological intervention and correct anaesthetic management using a rapid sequence induction. Treatment of acid aspiration is by suctioning after witnessed aspiration; antibiotics are indicated in patients with aspiration pneumonia only. Steroids are not proven to improve outcome or reduce mortality. Patients with acute lung injury requiring mechanical ventilation should be ventilated using lung protective strategies with low tidal volumes and low plateau pressure values, attempting to limit peak lung distension and end-expiratory collapse.

  3. [Congenital syphilis: incidence among newborns (United States)

    Araújo, E C; Moura, E F; Ramos, F L; Holanda, V G


    OBJECTIVE: To determine the incidence of congenital syphilis among newborns at the maternity of a public hospital. METHODS: The study was conducted at the maternity of Fundação Santa Casa de Misericórdia do Pará, from May to September 1996; 361 mothers were interviewed, and physical examination was performed in their newborns. Serum samples from both, mothers and neonates, were tested using three methods: VDRL, FTA - Abs, ELISA IgM. The diagnosis of congenital syphilis was established according to the criteria defined by Ministério da Saúde in 1993. RESULTS: The rate of congenital syphilis was of 9.1% (33); in 14 cases, there were one or more signs of the disease: prematurity, hepatomegaly, stillbirth, splenomegaly, perinatal death, abdominal distention, nasal stuffiness, jaundice, newborn small for gestational age. The majority of the infected mothers belonged to the age group of 20-35 years (81.8%); 60.6% were married; 63.6% received prenatal care; 48.5% reported previous spontaneous abortion, and 12.1% previous stillbirth. The rate of bisexuality among fathers was of 9.1%. CONCLUSION: The syphilis control measures and the prenatal care, have not been sufficient to prevent the high rate of the disease.

  4. Fuzzy Logic for Incidence Geometry (United States)


    The paper presents a mathematical framework for approximate geometric reasoning with extended objects in the context of Geography, in which all entities and their relationships are described by human language. These entities could be labelled by commonly used names of landmarks, water areas, and so forth. Unlike single points that are given in Cartesian coordinates, these geographic entities are extended in space and often loosely defined, but people easily perform spatial reasoning with extended geographic objects “as if they were points.” Unfortunately, up to date, geographic information systems (GIS) miss the capability of geometric reasoning with extended objects. The aim of the paper is to present a mathematical apparatus for approximate geometric reasoning with extended objects that is usable in GIS. In the paper we discuss the fuzzy logic (Aliev and Tserkovny, 2011) as a reasoning system for geometry of extended objects, as well as a basis for fuzzification of the axioms of incidence geometry. The same fuzzy logic was used for fuzzification of Euclid's first postulate. Fuzzy equivalence relation “extended lines sameness” is introduced. For its approximation we also utilize a fuzzy conditional inference, which is based on proposed fuzzy “degree of indiscernibility” and “discernibility measure” of extended points. PMID:27689133

  5. Acousto-optical Transducer with Surface Plasmons (United States)

    Kolomenskii, A. A.; Surovic, E.; Schuessler, H. A.


    The surface plasmon resonance (SPR) is a sensitive technique for the detection of changes in dielectric parameters in close proximity to a metal film supporting surface plasmon waves. Here we study the application of the SPR effect to an efficient conversion of an acoustic signal into an optical one. Such a transducer potentially has a large bandwidth and good sensitivity. When an acoustic wave is incident onto a receiving plate positioned within the penetration depth of the surface plasmons, it creates displacements of the surface of the plate and, thus, modulates the dielectric properties in the proximity of the gold film. This modulation, in turn, modifies the light reflection under surface plasmon resonance conditions. We simulate characteristics of this acousto-optical transducer with surface plasmons and provide sets of parameters at the optical wavelength of 800 nm and 633 nm for its realization.

  6. Neutron relativistic phenomenological and microscopic optical potential

    International Nuclear Information System (INIS)

    Shen Qing-biao; Feng Da-chun; Zhuo Yi-zhong


    In this paper, both the phenomenological and microscopic neutron relativistic optical potentials are presented. The global neutron relativistic phenomenological optical potential (RPOP) based on the available experimental data for various nuclei ranging from C to U with incident energies E n =20--1000 MeV has been obtained through an automatic search of the best parameters by computer. Then the nucleon relativistic microscopic optical potential (RMOP) is studied by utilizing the effective Lagrangian based on the popular Walecka model. Through comparison between the theoretical results and experimental data we shed some insight into both the RMOP and RPOP. Further improvement concerning how to combine the phenomenological potential with the microscopic one in order to reduce the number of free parameters appearing in the RPOP is suggested

  7. Experimental Characterization of Nonlinear Optical Materials (United States)

    Knox, Katie; Yang, Chuan; Liu, Zhiwen


    An optical system based on a half-wave plate-polarizer attenuator was designed to determine the transmitted light through materials that behave nonlinearly in the presence of high-energy picosecond laser pulses. The sample's nonlinear absorbance of a frequency-doubled Nd:YAG laser was measured as the energy of the incident light was regulated by the rotation of a half-wave plate. The optical system was used to measure the absorption of two linear samples as well as a nonlinear liquid crystal. Experimental results revealed that the optical material, which was composed of gold nanospheres in the nonlinear liquid L34, behaved as expected in the presence of lower input energies, but the attenuated beam did not reach a high enough energy to observe the full limiting effects of the nonlinear material.

  8. Incidence of childhood psychiatric disorders in India


    Malhotra, Savita; Kohli, Adarsh; Kapoor, Mehak; Pradhan, Basant


    Background: Studies on incidence of childhood mental disorders are extremely rare globally and there are none from India. Incidence studies though more difficult and time consuming, provide invaluable information on the pattern and causes of occurrence of mental disorders allowing opportunity for early intervention and primary prevention. Aim: This study aimed at estimating the incidence of psychiatric disorders in school children. Materials and Methods: A representative sample of school chil...

  9. Two /sup 238/Pu inhalation incidents

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, R.R.; Hall, R.M.


    Two employees inhaled significant amounts of /sup 238/Pu in separate unrelated contamination incidents in 1977. Both acute exposure incidents are described and the urine, feces, and in-vivo chest count data for each employee. Case B (/sup 238/PuNO/sub 3/) received 24 DTPA treatments beginning the day of the incident while, for medical reasons, Case A (/sup 238/PuO/sub 2/) received no therapy.

  10. Design of optical switches by illusion optics

    International Nuclear Information System (INIS)

    Shoorian, H R; Abrishamian, M S


    In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which blocks the waves at a stop band. By removing the illusion device, the waves propagate through the waveguide again. In addition, this method is used to remotely tune DBR optical properties such as resonant frequency and bandwidth in a wide range, which leads to a tunable filter for optical switching applications. Finally, using an illusion device at a distance, an optical cavity is created by inserting defects remotely in a DBR without any physical damage in the primary device. (paper)

  11. Design of optical switches by illusion optics (United States)

    Shoorian, H. R.; Abrishamian, M. S.


    In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which blocks the waves at a stop band. By removing the illusion device, the waves propagate through the waveguide again. In addition, this method is used to remotely tune DBR optical properties such as resonant frequency and bandwidth in a wide range, which leads to a tunable filter for optical switching applications. Finally, using an illusion device at a distance, an optical cavity is created by inserting defects remotely in a DBR without any physical damage in the primary device.

  12. A generative model for predicting terrorist incidents (United States)

    Verma, Dinesh C.; Verma, Archit; Felmlee, Diane; Pearson, Gavin; Whitaker, Roger


    A major concern in coalition peace-support operations is the incidence of terrorist activity. In this paper, we propose a generative model for the occurrence of the terrorist incidents, and illustrate that an increase in diversity, as measured by the number of different social groups to which that an individual belongs, is inversely correlated with the likelihood of a terrorist incident in the society. A generative model is one that can predict the likelihood of events in new contexts, as opposed to statistical models which are used to predict the future incidents based on the history of the incidents in an existing context. Generative models can be useful in planning for persistent Information Surveillance and Reconnaissance (ISR) since they allow an estimation of regions in the theater of operation where terrorist incidents may arise, and thus can be used to better allocate the assignment and deployment of ISR assets. In this paper, we present a taxonomy of terrorist incidents, identify factors related to occurrence of terrorist incidents, and provide a mathematical analysis calculating the likelihood of occurrence of terrorist incidents in three common real-life scenarios arising in peace-keeping operations

  13. Dynamic registration of an optical see-through HMD into a wide field-of-view rotorcraft flight simulation environment (United States)

    Viertler, Franz; Hajek, Manfred


    To overcome the challenge of helicopter flight in degraded visual environments, current research considers headmounted displays with 3D-conformal (scene-linked) visual cues as most promising display technology. For pilot-in-theloop simulations with HMDs, a highly accurate registration of the augmented visual system is required. In rotorcraft flight simulators the outside visual cues are usually provided by a dome projection system, since a wide field-of-view (e.g. horizontally > 200° and vertically > 80°) is required, which can hardly be achieved with collimated viewing systems. But optical see-through HMDs do mostly not have an equivalent focus compared to the distance of the pilot's eye-point position to the curved screen, which is also dependant on head motion. Hence, a dynamic vergence correction has been implemented to avoid binocular disparity. In addition, the parallax error induced by even small translational head motions is corrected with a head-tracking system to be adjusted onto the projected screen. For this purpose, two options are presented. The correction can be achieved by rendering the view with yaw and pitch offset angles dependent on the deviating head position from the design eye-point of the spherical projection system. Furthermore, it can be solved by implementing a dynamic eye-point in the multi-channel projection system for the outside visual cues. Both options have been investigated for the integration of a binocular HMD into the Rotorcraft Simulation Environment (ROSIE) at the Technische Universitaet Muenchen. Pros and cons of both possibilities with regard on integration issues and usability in flight simulations will be discussed.

  14. Nonlinear Optics and Applications (United States)

    Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)


    Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.

  15. Optimization of electro-optic phase shifters for integrated optical phased arrays (United States)

    Macik, Dwayne D.; Bravo, Tyler E.; Pentecost, Seeley M.; Espinal, Francisco A.; Madsen, Christi K.


    A low-loss, high-speed optical phased array (OPA) has been designed and fabricated. Two different platforms have been utilized in combination to leverage electro-optic (EO) tuning. A lithium niobate (LiNbO3) optical phased array was fabricated and used in conjunction with a silicon nitride (Si3N4) 8x8 waveguide array that condenses the output pitch and utilizes the TriplexTM waveguide technology. This OPA allows for the non-mechanical beam steering (NMBS) of 1550 nm light on an edge coupled optic platform and takes advantage of the high electro-optic coefficient and high speed capability of LiNbO3 for electro-optic phase tuning. This coupled OPA has an overall insertion loss of 3.5 dB which is advantageous to silicon-on-insulator OPAs that have shown overall insertion losses of 14 dB. To characterize and tune this device, a 3 lens imaging system was employed to produce both near- and far- field intensity patterns of the output of the OPA on a static image plane. At the image plane, a high resolution infrared camera was used to observe the resulting intensity pattern. The control software for tuning the OPA reads the intensity incident at a specified position on the detector array, and has a PWM interface to drive the electro-optic phase controls. Beam steering was accomplished using an iterative tuning algorithm.

  16. Theoretical Studies of Optical Properties of Silver Nanoparticles

    International Nuclear Information System (INIS)

    Ye-Wan, Ma; Zhao-Wang, Wu; Li-Hua, Zhang; Jie, Zhang


    Optical properties of silver nanoparticles such as extinction, absorption and scattering efficiencies are studied based on Green's function theory. The numerical simulation results show that optical properties of silver nanoparticles are mainly dependent on their sizes and geometries; the localized plasmon resonance peak is red shifted when the dielectric constant of the particle's surrounding medium increases or when a substrate is presented. The influences of wave polarizations, the incident angles of light, the composite silver and multiply-layers on the plasmon resonance are also reported. The numerical simulation of optical spectra is a very useful tool for nanoparticle growth and characterization. (fundamental areas of phenomenology(including applications))

  17. Polarization-selective optical transmission through a plasmonic metasurface

    Energy Technology Data Exchange (ETDEWEB)

    Pelzman, Charles; Cho, Sang-Yeon, E-mail: [Klipsch School of Electrical and Computer Engineering, New Mexico State University, Las Cruces, New Mexico, 88003-8001 (United States)


    We present the design, fabrication, and experimental characterization of a nanoslit-based metasurface that offers polarization-selective optical transmission for advanced imaging applications. The metasurface consists of an array of meta-atoms, constructed with two orthogonally coupled subwavelength apertures. Highly enhanced optical transmission was achieved by selective excitation of surface plasmon waves on the metasurface. By rotating the orientation of the linearly polarized incident beam, switching of enhanced optical transmission bands through the metasurface was experimentally demonstrated. This demonstration is a significant step towards developing advanced multispectral imaging devices.

  18. Near-Field Optical Microscopy of Fractal Structures

    DEFF Research Database (Denmark)

    Coello, Victor; Bozhevolnyi, Sergey I.


    Using a photon scanning tunnelling microscope combined with a shear-force feedback system, we image both topographical and near-field optical images (at the wavelengths of 633 and 594 nm) of silver colloid fractals. Near-field optical imaging is calibrated with a standing evanescent wave pattern....... Near-field optical images exhibit spatially localized (within 150-250 nm) intensity enhancement (by up to 20 times) in the form of round bright spots, whose positions and brightness are found to be sensitive to the light wavelength, polarization and angle of incidence. The observed phenomenon...

  19. Microstructure-mediated Optical Effects in Southern African Snakes

    Directory of Open Access Journals (Sweden)

    Singh Ishan


    Full Text Available The scales of the African Viper Bitis arietans were tested for optical effects. Spectral intensity was recorded at incident angles over the visible spectrum for dark, pale, and ventral scale regions. The lowest spectral intensity recordings were associated with scales which have the greatest level of micro-structuring. Our results indicate that scale appearance in B. arietans is a product of microstructure-mediated optical effects. The optical effect may play a role in improving the ecological performance of the snake in its natural environment.

  20. Microstructure-mediated Optical Effects in Southern African Snakes (United States)

    Singh, Ishan; Alexander, Graham


    The scales of the African Viper Bitis arietans were tested for optical effects. Spectral intensity was recorded at incident angles over the visible spectrum for dark, pale, and ventral scale regions. The lowest spectral intensity recordings were associated with scales which have the greatest level of micro-structuring. Our results indicate that scale appearance in B. arietans is a product of microstructure-mediated optical effects. The optical effect may play a role in improving the ecological performance of the snake in its natural environment.

  1. Introduction to nonimaging optics

    CERN Document Server

    Chaves, Julio


    Introduction to Nonimaging Optics covers the theoretical foundations and design methods of nonimaging optics, as well as key concepts from related fields. This fully updated, revised, and expanded Second Edition: Features a new and intuitive introduction with a basic description of the advantages of nonimaging opticsAdds new chapters on wavefronts for a prescribed output (irradiance or intensity), infinitesimal étendue optics (generalization of the aplanatic optics), and Köhler optics and color mixingIncorporates new material on the simultaneous multiple surface (SMS) design method in 3-D, int

  2. From optics testing to micro optics testing (United States)

    Brock, Christian; Dorn, Ralf; Pfund, Johannes


    Testing micro optics, i.e. lenses with dimensions down to 0.1mm and less, with high precision requires a dedicated design of the testing device, taking into account propagation and wave-optical effects. In this paper, we discuss testing methods based on Shack-Hartmann wavefront technology for functional testing in transmission and for the measurement of surface shape in reflection. As a first example of more conventional optics testing, i.e. optics in the millimeter range, we present the measurement of binoculars in transmission, and discuss the measured wave aberrations and imaging quality. By repeating the measurement at different wavelengths, information on chromatic effects is retrieved. A task that is often tackled using Shack-Hartman wavefront sensors is the alignment of collimation optics in front of a light source. In case of a micro-optical collimation unit with a 1/e² beam diameter of ca. 1mm, we need adapted relay optics for suitable beam expansion and well-defined imaging conditions. In this example, we will discuss the alignment process and effects of the relay optics magnification, as well as typical performance data. Oftentimes, micro optics are fabricated not as single pieces, but as mass optics, e.g. by lithographic processes. Thus, in order to reduce tooling and alignment time, an automated test procedure is necessary. We present an approach for the automated testing of wafer- or tray-based micro optics, and discuss transmission and reflection measurement capabilities. Exemplary performance data is shown for a sample type with 30 microns in diameter, where typical repeatabilities of a few nanometers (rms) are reached.

  3. Miniature Optical Isolator, Phase I (United States)

    National Aeronautics and Space Administration — To address NASA's need for miniature optical isolators in atom interferometry applications, Physical Optics Corporation (POC) proposes to develop a miniature optical...

  4. Computer incident response and forensics team management conducting a successful incident response

    CERN Document Server

    Johnson, Leighton


    Computer Incident Response and Forensics Team Management provides security professionals with a complete handbook of computer incident response from the perspective of forensics team management. This unique approach teaches readers the concepts and principles they need to conduct a successful incident response investigation, ensuring that proven policies and procedures are established and followed by all team members. Leighton R. Johnson III describes the processes within an incident response event and shows the crucial importance of skillful forensics team management, including when and where the transition to forensics investigation should occur during an incident response event. The book also provides discussions of key incident response components. Provides readers with a complete handbook on computer incident response from the perspective of forensics team management Identify the key steps to completing a successful computer incident response investigation Defines the qualities necessary to become a succ...

  5. Information Security Incident Management Practical Aspects

    Directory of Open Access Journals (Sweden)

    A. B. Kostina


    Full Text Available The information security incident management process model (ISIMP is developed; the role of this process in the information security management system is established. Input and output data of the process are determined. Key practical aspects of incident management are determined.

  6. Asphyxia Neonatorum-Incidence In Cape Town

    African Journals Online (AJOL)

    task of all concerned with the process of human repro- duction. In order to achieve this, a study of the incidence and risk factors of asphyxia neonatorum was undertaken in the Groote Schuur Maternity Hospital. TABLE I. INCIDENCE OF ASPHYXIA NEONATORUM. Source of. Hospital. Apgar score 0 - 3% information.

  7. The Incidence of Ankle Sprains in Orienteering. (United States)

    Ekstrand, Jan; And Others


    Investigates relationship between ankle sprains and participation time in competitive orienteering. Examined 15,474 competitors in races in the Swedish O-ringen 5-day event in 1987. Injuries requiring medical attention were analyzed, showing 137 (23.9 percent) ankle sprains. Injury incidence was 8.4/10,000 hours. Incidence of ankle sprains was…

  8. 49 CFR 1542.307 - Incident management. (United States)


    ... 49 Transportation 9 2010-10-01 2010-10-01 false Incident management. 1542.307 Section 1542.307 Transportation Other Regulations Relating to Transportation (Continued) TRANSPORTATION SECURITY ADMINISTRATION... Incident management. (a) Each airport operator must establish procedures to evaluate bomb threats, threats...

  9. Incidence and predictors of coronary stent thrombosis

    DEFF Research Database (Denmark)

    D'Ascenzo, Fabrizio; Bollati, Mario; Clementi, Fabrizio


    Stent thrombosis remains among the most feared complications of percutaneous coronary intervention (PCI) with stenting. However, data on its incidence and predictors are sparse and conflicting. We thus aimed to perform a collaborative systematic review on incidence and predictors of stent...... thrombosis....

  10. Incidence and antimicrobial susceptibility pattern of salmonella ...

    African Journals Online (AJOL)

    A study was carried out to investigate the incidence of Salmonella species among 300 children using stool samples from six hospitals in the metropolitan Kano. The organisms were investigated using cultural, serological biochemical characterization and sensitivity to some antimicrobial agents. The incidence of the bacteria ...

  11. Linux Incident Response Volatile Data Analysis Framework (United States)

    McFadden, Matthew


    Cyber incident response is an emphasized subject area in cybersecurity in information technology with increased need for the protection of data. Due to ongoing threats, cybersecurity imposes many challenges and requires new investigative response techniques. In this study a Linux Incident Response Framework is designed for collecting volatile data…

  12. Peptide Optical waveguides. (United States)

    Handelman, Amir; Apter, Boris; Shostak, Tamar; Rosenman, Gil


    Small-scale optical devices, designed and fabricated onto one dielectric substrate, create integrated optical chip like their microelectronic analogues. These photonic circuits, based on diverse physical phenomena such as light-matter interaction, propagation of electromagnetic waves in a thin dielectric material, nonlinear and electro-optical effects, allow transmission, distribution, modulation, and processing of optical signals in optical communication systems, chemical and biological sensors, and more. The key component of these optical circuits providing both optical processing and photonic interconnections is light waveguides. Optical confinement and transmitting of the optical waves inside the waveguide material are possible due to the higher refractive index of the waveguides in comparison with their surroundings. In this work, we propose a novel field of bionanophotonics based on a new concept of optical waveguiding in synthetic elongated peptide nanostructures composed of ordered peptide dipole biomolecules. New technology of controllable deposition of peptide optical waveguiding structures by nanofountain pen technique is developed. Experimental studies of refractive index, optical transparency, and linear and nonlinear waveguiding in out-of-plane and in-plane diphenylalanine peptide nanotubes have been conducted. Optical waveguiding phenomena in peptide structures are simulated by the finite difference time domain method. The advantages of this new class of bio-optical waveguides are high refractive index contrast, wide spectral range of optical transparency, large optical nonlinearity, and electro-optical effect, making them promising for new applications in integrated multifunctional photonic circuits. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  13. Graphene, plasmons and transformation optics

    International Nuclear Information System (INIS)

    Huidobro, P A; Kraft, M; Maier, S A; Pendry, J B; Kun, R


    Here we study subwavelength gratings for coupling into graphene plasmons by means of an analytical model based on transformation optics that is not limited to very shallow gratings. We consider gratings that consist of a periodic modulation of the charge density in the graphene sheet, and gratings formed by this conductivity modulation together with a dielectric grating placed in close vicinity of the graphene. Explicit expressions for the dispersion relation of the plasmon polaritons supported by the system, and reflectance and transmittance under plane wave illumination are given. We discuss the conditions for maximising the coupling between incident radiation and plasmons in the graphene, finding the optimal modulation strength for a conductivity grating. (paper)

  14. Optical design of an off-axis mirror based solar concentrator (United States)

    Trespidi, Franco; Timò, Gianluca


    It is presented the optical design of a mirror based solar concentrator operating at concentrating factors higher than 850suns with an optical efficiency greater than 83% and an angular acceptance of at least ±0.5°. The optical system consists of an off-axis primary mirror optimized to work in conjunction with a secondary optical element which homogenizes the light on the photovoltaic (PV) cell and also increases the acceptance angle of the solar concentrator. Since in a high concentrating system the collected optical radiation can impinge on the PV cell also at high incidence angles, during the optical design and optimization particular attention was paid to reduce the number of rays impinging on the PVcell at high incidence angle. Furthermore the angular response of the PV cell was included to calculate the efficiency value of the whole system and to calculate the spatial distribution of the photocurrent in the different subcells constituting the multi-junction solar cell.

  15. Mechanistic studies for optical switching materials for space environments (United States)

    Rayfield, George W.; Sarkar, Abhijit; Rahman, Salma; Godschalx, James P.; Taylor, Edward W.


    Optical power limiters (OPLs) are nonlinear optical (NLO) devices that limit the amount of energy transmitted in an optical system. At low incident optical power or pulse energy, the transmission of the system is high enough to allow nominal operation of the system. At high incident optical power or pulse energy, the transmission decreases to protect sensitive components such as optical receivers or transmitters. The interest OPLs for use in the space environment is due to the increasingly large number of space based missions and devices that require laser protection from laser beam is coming from, an enemy, misaligned laser in equipment, etc. Temperature and space radiation-induced effects in optical and electronic materials are well known and they can cause disruption in OPL functions, or in the worst case, failure of the sensor. Recently, certain hyperbranched polymer-based composites containing OPL chromophores have been developed that offer high OPL performance and have been shown to function in a simulated + space environment. One novel high performance polymer material containing carbon nanotubes (CNT) covalently attached to the polymer host is promising. Preliminary light scattering measurements suggest that nonlinear scattering is not the primary mechanism for OPL performance.

  16. Predicting incident size from limited information

    International Nuclear Information System (INIS)

    Englehardt, J.D.


    Predicting the size of low-probability, high-consequence natural disasters, industrial accidents, and pollutant releases is often difficult due to limitations in the availability of data on rare events and future circumstances. When incident data are available, they may be difficult to fit with a lognormal distribution. Two Bayesian probability distributions for inferring future incident-size probabilities from limited, indirect, and subjective information are proposed in this paper. The distributions are derived from Pareto distributions that are shown to fit data on different incident types and are justified theoretically. The derived distributions incorporate both inherent variability and uncertainty due to information limitations. Results were analyzed to determine the amount of data needed to predict incident-size probabilities in various situations. Information requirements for incident-size prediction using the methods were low, particularly when the population distribution had a thick tail. Use of the distributions to predict accumulated oil-spill consequences was demonstrated

  17. Customer focused incident monitoring in anaesthesia. (United States)

    Khan, F A; Khimani, S


    The database of incident forms relating to anaesthesia services in an institutional risk management programme were reviewed for 2003-2005, the aim being to identify any recurring patterns. Incidents were prospectively categorised as relating to attitude/behaviour, communication breakdown, delay in service, or were related to care, cost, environment, equipment, security, administrative process, quality of service or miscellaneous. The total number of anaesthesia-related incidents reported during the period was 287, which related to 0.44% of the total number of anaesthetics administered during the time period. In all, 170 incidents were reported by the department, 96 by internal customers and 21 by external customers. Only 30% of the complaints came from the operating room. Thirty-four per cent of all incidents related to communication, behaviour and delay in service. A requirement to teach communication skills and stress handling formally in anaesthesia training programmes, and at the time of induction of staff into the department, has been identified.

  18. Optical characteristics of transparent samarium oxide thin films ...

    Indian Academy of Sciences (India)


    Oct 7, 2016 ... spectra at nearly normal incident light. The estimated direct optical band gap energy (Ed g) values were found to increase by increasing the annealing temperatures. The dispersion curves of the refractive index of Sm2O3 thin films were found to obey the single oscillator model. Keywords. Transparent oxide ...

  19. Analysis of the normal optical, Michel and molecular potentials on ...

    Indian Academy of Sciences (India)

    Full finite-range (FFR) distorted-wave Born approximation (DWBA) method has been applied to analyse the angular distributions of cross-sections of the 40 Ca( 6 Li, d) 44 Ti reaction at 28 MeV incident energy for the 22 transitions involving both the bound and unbound states of 44 Ti byusing the normal optical, Michel and ...

  20. An Evanescent Field Optical Microscope. Scanning probe Microscopy

    NARCIS (Netherlands)

    van Hulst, N.F.; Segerink, Franciscus B.; Bölger, B.; Bölger, B.; Wickramasinghe, H. Kumar


    An Evanescent Field Optical Microscope (EFOM) is presented, which employs frustrated total internal reflection on a highly localized scale by means of a sharp dielectric tip. The coupling of the evanescent field to the sub-micrometer probe as a function of probe-sample distance, angle of incidence

  1. Interaction of solitary pulses in single mode optical fibres | Usman ...

    African Journals Online (AJOL)

    Two solitary waves launched, by way of incidence, into an optical fibre from a single pulse if the pulses are in-phase as understood from results of inverse scattering transform method applied to the cubic nonlinear Schrödinger equations, (CNLSE\\'s). The single CNLSE is then understood to describe evolution of coupled ...

  2. Optical antennas for far and near field metrology

    NARCIS (Netherlands)

    Silvestri, F.; Bernal Arango, F.; Vendel, K.J.A.; Gerini, G.; Bäumer, S.M.B.; Koenderink, A.F.


    This paper presents the use of optical antennas in metrology scenarios. Two design concepts are presented: dielectric nanoresonator arrays and plasmonic nanoantennas arrays. The first ones are able to focus an incident light beam at an arbitrary focal plane. The nanoantennas arrays can be employed

  3. Specialty-based, voluntary incident reporting in neonatal intensive care: description of 4846 incident reports

    NARCIS (Netherlands)

    Snijders, C.; van Lingen, R. A.; Klip, H.; Fetter, W. P. F.; van der Schaaf, T. W.; Molendijk, H. A.; Kok, J. H.; te Pas, E.; Pas, H.; van der Starre, C.; Bloemendaal, E.; Lopes Cardozo, R. H.; Molenaar, A. M.; Giezen, A.; Maat, H. E.; Molendijk, A.; Lavrijssen, S.; Mulder, A. L. M.; de Kleine, M. J. K.; Koolen, A. M. P.; Schellekens, M.; Verlaan, W.; Vrancken, S.; Schotman, L.; van der Zwaan, A.; van der Tuijn, Y.; Tibboel, D.; Kollen, B. J.


    OBJECTIVES: To examine the characteristics of incidents reported after introduction of a voluntary, non-punitive incident reporting system for neonatal intensive care units (NICUs) in the Netherlands; and to investigate which types of reported incident pose the highest risk to patients in the NICU.

  4. Optical Airborne Tracker System (United States)

    National Aeronautics and Space Administration — The Optical Airborne Tracker System (OATS) is an airborne dual-axis optical tracking system capable of pointing at any sky location or ground target.  The objectives...

  5. The Scanning Optical Microscope. (United States)

    Sheppard, C. J. R.


    Describes the principle of the scanning optical microscope and explains its advantages over the conventional microscope in the improvement of resolution and contrast, as well as the possibility of producing a picture from optical harmonies generated within the specimen.

  6. Optics for SIERRA (United States)

    National Aeronautics and Space Administration — To demonstrate a massively parallel optical ray trace to enable the design and analysis of extremely large aperture optical systems. This, in turn, enables...

  7. Fiber Optics Technology. (United States)

    Burns, William E.


    Discusses various applications of fiber optics technology: information systems, industrial robots, medicine, television, transportation, and training. Types of jobs that will be available with fiber optics training (such as electricians and telephone cable installers and splicers) are examined. (CT)

  8. Fiber Optics Instrumentation Development (United States)

    Chan, Patrick Hon Man; Parker, Allen R., Jr.; Richards, W. Lance


    This is a general presentation of fiber optics instrumentation development work being conducted at NASA Dryden for the past 10 years and recent achievements in the field of fiber optics strain sensors.

  9. Optical illusion: apogee development


    Elena, Chernyсhuk; Bazylevych, Viktoriya


    The article provides a classification of optical illusions performed by the authors. Briefly described each of the 11 identified species. Offered the variants using optical illusions in the urban environment, exterior and interior.

  10. An optical tunable filter array based on LCOS phase grating (United States)

    Feng, Dong; Wan, Zhujun; Chen, Xu; Yan, Shijia; Luo, Zhixiang


    This paper reports an optical tunable filter array (TFA) based on a LCOS (liquid crystal on silicon) chip. The input broadband optical beam is first dispersed by a bulk grating and then incident on the LCOS chip. The LCOS chip is phase-only modulated and constructed as a dynamic reflective phase grating. The phase modulation is adjusted to meet the Littrow angle for a specified passband wavelength and thus the optical beam corresponding to this wavelength is steered to the output. The input/output optical beams are coupled to optical fibers with a dual-fiber collimator. Four dualfiber collimators are vertically aligned as the inputs/outputs and the pixels of the LCOS chip are vertically allocated as four independent zones. Thus the device can act as a 4-channel TFA, which is assembled and functionally demonstrated.

  11. The radial shapes of intermediate energy microscopic optical potentials

    International Nuclear Information System (INIS)

    Shen Qingbiao; Wang Chang; Tian Ye; Zhuo Yizhong


    The radial shapes of intermediate energy proton microscopic optical potentials of 40 Ca are calculated with nuclear matter approach by Skyrme interactions. The calculated results show that the real central potential in central region of nucleus changes from attractive to repulsive when the energy of incident nucleon is above 150 MeV and appears apparently a 'wine-bottle-bottom' shape in the transition energy region (from 150 MeV to 300 MeV). This tendency is consistent with empirical optical potential obtained through fitting experiments and microscopic optical potential calculated with relativistic mean field theory as well as with the BHF theory. The calculated imaginary part of the microscopic optical potential changes from the dominant surface absorption into the volume absorption and its absolute value become larger as energy increases. The effects of Skyrme force parameters to the radial shape of the calculated microscopic optical potential are analysed in detail

  12. Optical combing to align photoreceptors in detached retinas (United States)

    Yin, Shizhuo; Gardner, Thomas W.; Wu, Fei; Cholker, Milind S.


    In this paper, we presented a novel micro-manipulating method, called 'optical combing', that could improve the retina reattachment surgery results. Optical combing adopts the working principle of optical tweezers (i.e., focused Gaussian beam produces a trapping force when it incidents onto a micro-object. The trapping force can pull the micro-object to the central point of focused laser beam. Optical combing is implemented by scanning a focused laser beam on the misaligned micro objects (such as misaligned photoreceptors). In our preliminary experiment, a set of misaligned micro glass rods was re-aligned by applying this optical combing technology, which verified our theory. In the future, this technique will be used to re-align misaligned photoreceptors in real retina.

  13. Advanced digital optical communications

    CERN Document Server

    Binh, Le Nguyen


    This book provides a fundamental understanding of digital communication applications in optical communication technologies. Emphasizing operation principles versus mathematical analysis, the Second Edition includes new coverage of superchannel optical transmission systems, metropolitan and long-haul optical systems and networks, and Nyquist pulse shaping and high spectral efficiency of optical transmission systems, as well as new homework problems and examples. Featuring theoretical foundations as well as practical case studies, the text focuses on enhancements to digital technologies that are

  14. Emerging Correlation Optics

    DEFF Research Database (Denmark)

    Angelsky, Oleg V.; Gbur, Gregory J.; Polyanskii, Peter


    This feature issue of Applied Optics contains a series of selected papers reflecting the state-of-the-art of correlation optics and showing synergetics between the theoretical background and experimental techniques.......This feature issue of Applied Optics contains a series of selected papers reflecting the state-of-the-art of correlation optics and showing synergetics between the theoretical background and experimental techniques....

  15. Progress in optics

    CERN Document Server

    Wolf, Emil


    In the fourty-seven years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. The volumes in this series which have appeared up to now contain more than 300 review articles by distinguished research workers, which have become permanent records for many important developments.- Backscattering and Anderson localization of light- Advances in oliton manipulation in optical lattices- Fundamental quantum noise in optical amplification- Invisibility cloaks

  16. Progress in optics

    CERN Document Server

    Wolf, Emil


    The Progress in Optics series contains more than 300 review articles by distinguished research workers, which have become permanent records for many important developments, helping optical scientists and optical engineers stay abreast of their fields. Comprehensive, in-depth reviewsEdited by the leading authority in the field

  17. Multiplane optical microscope

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tongcang; Ota, Sadao; Kim, Jeongmin; Wang, Yuan; Zhang, Xiang


    This disclosure provides systems, methods, and apparatus related to optical microscopy. In one aspect, an apparatus includes a sample holder, a first objective lens, a plurality of optical components, a second objective lens, and a mirror. The apparatus may directly image a cross-section of a sample oblique to or parallel to the optical axis of the first objective lens, without scanning.

  18. Fun with Optical Fibres (United States)

    Alti, Kamlesh


    Optical fibres play a very crucial role in today's technologies. Academic courses in optical fibres start at the undergraduate level. Nevertheless, student's curiosity towards optical fibres starts from the school level. In this paper, some fun experiments have been designed for both school and college students, which have some concrete…

  19. Optical ordinal optimization (United States)

    Caulfield, H. John


    Ordinal optimization is a relatively new field of mathematics that seems never to have been applied to optics. Optics has made extensive use of traditional cardinal optimization. This paper explores the possibility that ordinal optimization might be useful in optics. The conclusion is: Not directly but indirectly.

  20. Trends in the incidence and causes of severe visual impairment and blindness in children from Israel. (United States)

    Mezer, Eedy; Chetrit, Angela; Kalter-Leibovici, Ofra; Kinori, Michael; Ben-Zion, Itay; Wygnanski-Jaffe, Tamara


    To describe trends in the incidence and causes of legal childhood blindness in Israel, one of the few countries worldwide that maintain a national registry of the blind. We performed a historical cohort study of annual reports of the National Registry of the Blind (NRB) between 1999 and 2013. All data regarding demographic information, year of registration and cause of blindness of children 0-18 years of age registered for blind certification were obtained from the annual reports of the NRB. Causes of legal blindness analyzed were optic atrophy, retinitis pigmentosa, retinopathy of prematurity (ROP), albinism, other retinal disorders, cataract, and glaucoma. The main outcome measure was the incidence of new cases of certified legal blindness. The incidence of newly registered legally blind children in Israel almost halved from 7.7 per 100,000 in 1999 to 3.1 per 100,000 in 2013. The decline was mainly attributable to a decreased incidence of blindness resulting from retinitis pigmentosa and ROP. The incidence of registered cases due to cerebral visual impairment increased. During the past decade the incidence of severe childhood visual impairment and blindness declined in Israel. A continuous decline in consanguineous marriages among the Jewish and Arab populations in Israel may have contributed to the decrease in the rate of vision loss due to retinitis pigmentosa in children. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  1. Taxonometric Applications in Radiotherapy Incident Analysis

    International Nuclear Information System (INIS)

    Dunscombe, Peter B.; Ekaette, Edidiong U.; Lee, Robert C.; Cooke, David L.


    Recent publications in both the scientific and the popular press have highlighted the risks to which patients expose themselves when entering a healthcare system. Patient safety issues are forcing us to, not only acknowledge that incidents do occur, but also actively develop the means for assessing and managing the risks of such incidents. To do this, we ideally need to know the probability of an incident's occurrence, the consequences or severity for the patient should it occur, and the basic causes of the incident. A structured approach to the description of failure modes is helpful in terms of communication, avoidance of ambiguity, and, ultimately, decision making for resource allocation. In this report, several classification schemes or taxonomies for use in risk assessment and management are discussed. In particular, a recently developed approach that reflects the activity domains through which the patient passes and that can be used as a basis for quantifying incident severity is described. The estimation of incident severity, which is based on the concept of the equivalent uniform dose, is presented in some detail. We conclude with a brief discussion on the use of a defined basic-causes table and how adding such a table to the reports of incidents can facilitate the allocation of resources

  2. EUV optics in photoionization experiments (United States)

    Bartnik, Andrzej; Wachulak, Przemysław; Fiedorowicz, Henryk; Fok, Tomasz; Jarocki, Roman; Kostecki, Jerzy; Szczurek, Anna; Szczurek, Mirosław; Pina, Ladislav; Sveda, Libor


    In this work photoionized plasmas were created by irradiation of He, Ne and Ar gases with a focused EUV beam from one of two laser-plasma sources employing Nd:YAG laser systems of different parameters. First of them was a 10-Hz laser-plasma EUV source, based on a double-stream gas-puff target, irradiated with the 3-ns/0.8J laser pulse. EUV radiation in this case was focused using a gold-plated grazing incidence ellipsoidal collector in the wavelength range λ = 9÷70 nm. The most intense emission was in the relatively narrow spectral region centred at λ = 11 +/- 1 nm. The second source was based on a 10 ns/10 J/10 Hz laser system. In this case EUV radiation was focused using a gold-plated grazing incidence multifoil collector or a Mo-coated ellipsoidal collector. The most intense emission in this case was in the 5 ÷ 15 nm spectral region. Radiation fluence ranged from 60 mJ/cm2 to 400 mJ/cm2. Different gases were injected into the interaction region, perpendicularly to an optical axis of the irradiation system, using an auxiliary gas puff valve. Irradiation of the gases resulted in ionization and excitation of atoms and ions. Spectra in EUV range were measured using a grazing incidence, flat-field spectrometer (McPherson Model 251), equipped with a 450 lines/mm toroidal grating. In all cases the most intense emission lines were assigned to singly charged ions. The other emission lines belong to atoms or doubly charged ions. The spectra were excited in low density gases of the order of 1 ÷ 10% atmospheric density.

  3. Behavior of obliquely incident vector Bessel beams at planar interfaces

    KAUST Repository

    Salem, Mohamed


    We investigate the behavior of full-vector electromagnetic Bessel beams obliquely incident at an interface between two electrically different media. We employ a Fourier transform domain representation of Bessel beams to determine their behavior upon reflection and transmission. This transform, which is geometric in nature, consists of elliptical support curves with complex weighting associated with them. The behavior of the scattered field at an interface is highly complex, owing to its full-vector nature; nevertheless, this behavior has a straightforward representation in the transform domain geometry. The analysis shows that the reflected field forms a different vector Bessel beam, but in general, the transmitted field cannot be represented as a Bessel beam. Nevertheless, using this approach, we demonstrate a method to propagate a Bessel beam in the refractive medium by launching a non- Bessel beam at the interface. Several interesting phenomena related to the behavior of Bessel beams are illustrated, such as polarized reflection at Brewster\\'s angle incidence, and the Goos-Hänchen and Imbert-Federov shifts in the case of total reflection. © 2013 Optical Society of America.

  4. The Marshall Grazing Incidence X-ray Spectrometer (United States)

    Kobayashi, Ken; Winebarger, Amy R.; Savage, Sabrina; Champey, Patrick; Cheimets, Peter N.; Hertz, Edward; Bruccoleri, Alexander R.; Golub, Leon; Ramsey, Brian; Ranganathan, Jaganathan; Marquez, Vanessa; Allured, Ryan; Parker, Theodore; Heilmann, Ralf K.; Schattenburg, Mark L.


    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a NASA sounding rocket instrument designed to obtain spatially resolved soft X-ray spectra of the solar atmosphere in the 6-24 Å (0.5-2.0 keV) range. The instrument consists of a single shell Wolter Type-I telescope, a slit, and a spectrometer comprising a matched pair of grazing incidence parabolic mirrors and a planar varied-line space diffraction grating. The instrument is designed to achieve a 50 mÅ spectral resolution and 5 arcsecond spatial resolution along a +/-4-arcminute long slit, and launch is planned for 2019. We report on the status and our approaches for fabrication and alignment for this novel optical system. The telescope and spectrometer mirrors are replicated nickel shells, and are currently being fabricated at the NASA Marshall Space Flight Center. The diffraction grating is currently under development by the Massachusetts Institute of Technology (MIT); because of the strong line spacing variation across the grating, it will be fabricated through e-beam lithography.

  5. Incidence of ascariasis in gastric carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Woo; Rhee, Hak Song; Bahk, Yong Whee [St Mary' s Hospital Catholic Medical College, Seoul (Korea, Republic of)


    Prompted by the finding that the radiological incidence of small bowel ascariasis in the patient with gastric carcinoma was unexpectedly lower than the incidence in the normal population, a clinical study was performed to investigate possible relationship between gastric carcinoma and intestinal ascariasis. As a preliminary survey, we reviewed the radiological incidence of ascariasis in a total of 2,446 cases of upper GI series performed at the Department of Radiology, St Mary's Hospital Catholic Medical College. These included 1,573 normal subjects, 146 gastric carcinoma patients, 100 benign gastric ulcer and 249 duodenal ulcer patients and 378 other upper GI diseases. Following the preliminary study, a more accurate parasitologic study was conducted in another 578 normal subjects and 51 gastric carcinoma patients. The radiological incidences of ascaiasis in normal subjects and gastric carcinoma patients were 15.1% and 28.1%, respectively. The incidence of overall helminthiasis including ascaris lumbricoides, trichocephalus trichiurus and trichostrongyloides orientalis in normal subjects of the present series was 73.5%. This figure is virtually the same with 69.1% of the general population incidence reported by Kim, et al. (1971), but the incidence in gastric carcinoma patients was 94.1%. The high incidence pattern of overall helminthiasis in gastric carcinoma patients is, however, reversed as for as ascariasis is concerned. Thus, the incidence of ascariasis of gastric carcinoma patients was much lower than that of normal subjects (9.8% vs 19.4%). From the present observation, it is postulated that there can be some possible antagonistic relationship between evolution of gastric carcinoma and small bowel infestation of ascaris lumbricoides.

  6. Optical polarization: background and camouflage (United States)

    Škerlind, Christina; Hallberg, Tomas; Eriksson, Johan; Kariis, Hans; Bergström, David


    Polarimetric imaging sensors in the electro-optical region, already military and commercially available in both the visual and infrared, show enhanced capabilities for advanced target detection and recognition. The capabilities arise due to the ability to discriminate between man-made and natural background surfaces using the polarization information of light. In the development of materials for signature management in the visible and infrared wavelength regions, different criteria need to be met to fulfil the requirements for a good camouflage against modern sensors. In conventional camouflage design, the aimed design of the surface properties of an object is to spectrally match or adapt it to a background and thereby minimizing the contrast given by a specific threat sensor. Examples will be shown from measurements of some relevant materials and how they in different ways affect the polarimetric signature. Dimensioning properties relevant in an optical camouflage from a polarimetric perspective, such as degree of polarization, the viewing or incident angle, and amount of diffuse reflection, mainly in the infrared region, will be discussed.

  7. Violent incidents on a regional secure unit. (United States)

    Rïx, G; Seymour, D


    This 1-year retrospective study was conducted on a regional secure unit at the Bethlem Royal Hospital, London, using the hospital's data collection sheet for violent incidents. The majority of incidents were minor in nature but there were a few assaults that involved pain, lacerations or bruising. Although violence was common to the majority of patients, two contributed a large number. Those staff at the bottom of the nursing hierachy who spent most time with patients were most at risk. Likewise fellow patients were also often involved in incidents. Violence did not tail off after the breakfast period, as reported in previous studies, but continued to rise until bedtime.

  8. Trip-timing decisions with traffic incidents

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Lindsey, Robin


    This paper analyzes traffic bottleneck congestion when drivers randomly cause incidents that temporarily block the bottleneck. Drivers have general scheduling preferences for time spent at home and at work. They independently choose morning departure times from home to maximize expected utility...... without knowing whether an incident has occurred. The resulting departure time pattern may be compressed or dispersed according to whether or not the bottleneck is fully utilized throughout the departure period on days without incidents. For both the user equilibrium (UE) and the social optimum (SO...

  9. Injury incidence and balance in rugby players. (United States)

    M, Jaco Ras; Puckree, Threethambal


    Objective : This study determined and correlated injury incidence and balance in rugby players. A prospective survey with balance testing was conducted on first year rugby academy players (N= 114). Injury incidence, static and dynamic balance were tested pre and post-season using a Biosway portable balance system. The data was analysed using paired and independent samples t-tests at pscrum-half (14.80%) playing position, injuries in the 2nd half of the match (57%), and during contact (67%). Conclusion : Injury incidence was related to static and dynamic balance in forward right direction only.

  10. Near perfect optics

    Energy Technology Data Exchange (ETDEWEB)

    Goeke, R.; Farnsworth, A.V.; Neumann, C.C.; Sweatt, W.C.; Warren, M.E.; Weed, J.W.


    This report discusses a novel fabrication process to produce nearly perfect optics. The process utilizes vacuum deposition techniques to optimally modify polished optical substrate surfaces. The surface figure, i.e. contour of a polished optical element, is improved by differentially filling in the low spots on the surface using flux from a physical vapor deposition source through an appropriate mask. The process is expected to enable the manufacture of diffraction-limited optical systems for the UV, extreme UV, and soft X-ray spectral regions, which would have great impact on photolithography and astronomy. This same technique may also reduce the fabrication cost of visible region optics with aspheric surfaces.

  11. Optical modulator including grapene (United States)

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang


    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  12. Optical Binding of Nanowires

    Czech Academy of Sciences Publication Activity Database

    Simpson, Stephen Hugh; Zemánek, Pavel; Marago, O.M.; Jones, P.H.; Hanna, S.


    Roč. 17, č. 6 (2017), s. 3485-3492 ISSN 1530-6984 R&D Projects: GA ČR GB14-36681G Grant - others:AV ČR(CZ) CNR-16-12 Program:Bilaterální spolupráce Institutional support: RVO:68081731 Keywords : optical binding nanowires * Brownian motion * self -organization * non-equilibrium thermodynamics * non-equilibrium steady state * spin-orbit coupling * emergent phenomena Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 12.712, year: 2016

  13. Small scale optics

    CERN Document Server

    Yupapin, Preecha


    The behavior of light in small scale optics or nano/micro optical devices has shown promising results, which can be used for basic and applied research, especially in nanoelectronics. Small Scale Optics presents the use of optical nonlinear behaviors for spins, antennae, and whispering gallery modes within micro/nano devices and circuits, which can be used in many applications. This book proposes a new design for a small scale optical device-a microring resonator device. Most chapters are based on the proposed device, which uses a configuration know as a PANDA ring resonator. Analytical and nu

  14. [Adaptive optics for ophthalmology]. (United States)

    Saleh, M


    Adaptive optics is a technology enhancing the visual performance of an optical system by correcting its optical aberrations. Adaptive optics have already enabled several breakthroughs in the field of visual sciences, such as improvement of visual acuity in normal and diseased eyes beyond physiologic limits, and the correction of presbyopia. Adaptive optics technology also provides high-resolution, in vivo imaging of the retina that may eventually help to detect the onset of retinal conditions at an early stage and provide better assessment of treatment efficacy. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Optic disc oedema

    DEFF Research Database (Denmark)

    Nielsen, Marianne Kromann; Hamann, Steffen


    Optic disc oedema describes the nonspecific, localized swelling of the optic nerve head regardless of aetiology. Therefore, differentiating among the various aetiologies depends on a thorough history and knowledge of the clinical characteristics of the underlying conditions. Papilloedema strictly...... refers to optic disc oedema as a consequence of elevated intracranial pressure. It is usually a bilateral condition and visual function is preserved until late. Optic disc oedema caused by an anterior optic neuropathy is usually unilateral and accompanied by the loss of visual function....

  16. Progress in optics

    CERN Document Server

    Wolf, Emil


    In the thirty-seven years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. At the time of inception of this series, the first lasers were only just becoming operational, holography was in its infancy, subjects such as fiber optics, integrated optics and optoelectronics did not exist and quantum optics was the domain of only a few physicists. The term photonics had not yet been coined. Today these fields are flourishing and have become areas of specialisation for many science and engineering students and n

  17. Progress in optics

    CERN Document Server

    Wolf, Emil


    In the thirty-seven years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. At the time of inception of this series, the first lasers were only just becoming operational, holography was in its infancy, subjects such as fiber optics, integrated optics and optoelectronics did not exist and quantum optics was the domain of only a few physicists. The term photonics had not yet been coined. Today these fields are flourishing and have become areas of specialisation for many science and engineering students and n

  18. Peptide Integrated Optics. (United States)

    Handelman, Amir; Lapshina, Nadezda; Apter, Boris; Rosenman, Gil


    Bio-nanophotonics is a wide field in which advanced optical materials, biomedicine, fundamental optics, and nanotechnology are combined and result in the development of biomedical optical chips. Silk fibers or synthetic bioabsorbable polymers are the main light-guiding components. In this work, an advanced concept of integrated bio-optics is proposed, which is based on bioinspired peptide optical materials exhibiting wide optical transparency, nonlinear and electrooptical properties, and effective passive and active waveguiding. Developed new technology combining bottom-up controlled deposition of peptide planar wafers of a large area and top-down focus ion beam lithography provides direct fabrication of peptide optical integrated circuits. Finding a deep modification of peptide optical properties by reconformation of biological secondary structure from native phase to β-sheet architecture is followed by the appearance of visible fluorescence and unexpected transition from a native passive optical waveguiding to an active one. Original biocompatibility, switchable regimes of waveguiding, and multifunctional nonlinear optical properties make these new peptide planar optical materials attractive for application in emerging technology of lab-on-biochips, combining biomedical photonic and electronic circuits toward medical diagnosis, light-activated therapy, and health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo


    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  20. Optical logic: an overview (United States)

    Caulfield, H. John


    Progress of optical logic has been anything but uniform or even monotonic. The hope for "all optical computers" was largely abandoned after devastating critiques by Keyes. Over time, optical logic transformed into a very viable niche activity by the needs of optical communication for "all optical" logic and the advent of a critical component: the SOA or Semiconductor Optical Amplifier. I argue that a new phase in this uneven history can be defined - linear (single photon, not multiple entangled photon) quantum optical logic. These can perform conservative, reversible logic operations without energy or time penalties, but cascading requires the irreversible act of measurement, so only single devices or single layers can deliver those advantages.

  1. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch


    The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

  2. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch


    at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...... glaucoma patients is six times higher at a perfusion pressure of 30 mmHg, which corresponds to a level where the optic nerve is hypoxic in experimental animals, as compared to perfusion pressure levels above 50 mmHg where the optic nerve is normoxic. Medical intervention can affect optic nerve oxygen......-oxygenase inhibitor, indomethacin, which indicates that prostaglandin metabolism plays a role. Laboratory studies suggest that carbonic anhydrase inhibitors might be useful for medical treatment of optic nerve and retinal ischemia, potentially in diseases such as glaucoma and diabetic retinopathy. However, clinical...

  3. Optical system design

    CERN Document Server

    Fischer, Robert F


    Honed for more than 20 years in an SPIE professional course taught by renowned optical systems designer Robert E. Fischer, Optical System Design, Second Edition brings you the latest cutting-edge design techniques and more than 400 detailed diagrams that clearly illustrate every major procedure in optical design. This thoroughly updated resource helps you work better and faster with computer-aided optical design techniques, diffractive optics, and the latest applications, including digital imaging, telecommunications, and machine vision. No need for complex, unnecessary mathematical derivations-instead, you get hundreds of examples that break the techniques down into understandable steps. For twenty-first century optical design without the mystery, the authoritative Optical Systems Design, Second Edition features: Computer-aided design use explained through sample problems Case studies of third-millennium applications in digital imaging, sensors, lasers, machine vision, and more New chapters on optomechanic...

  4. MEMS optical sensor

    DEFF Research Database (Denmark)


    The present invention relates to an all-optical sensor utilizing effective index modulation of a waveguide and detection of a wavelength shift of reflected light and a force sensing system accommodating said optical sensor. One embodiment of the invention relates to a sensor system comprising...... at least one multimode light source, one or more optical sensors comprising a multimode sensor optical waveguide accommodating a distributed Bragg reflector, at least one transmitting optical waveguide for guiding light from said at least one light source to said one or more multimode sensor optical...... waveguides, a detector for measuring light reflected from said Bragg reflector in said one or more multimode sensor optical waveguides, and a data processor adapted for analyzing variations in the Bragg wavelength of at least one higher order mode of the reflected light....

  5. Theory and analysis of a large field polarization imaging system with obliquely incident light. (United States)

    Lu, Xiaotian; Jin, Weiqi; Li, Li; Wang, Xia; Qiu, Su; Liu, Jing


    Polarization imaging technology provides information about not only the irradiance of a target but also the polarization degree and angle of polarization, which indicates extensive application potential. However, polarization imaging theory is based on paraxial optics. When a beam of obliquely incident light passes an analyser, the direction of light propagation is not perpendicular to the surface of the analyser and the applicability of the traditional paraxial optical polarization imaging theory is challenged. This paper investigates a theoretical model of a polarization imaging system with obliquely incident light and establishes a polarization imaging transmission model with a large field of obliquely incident light. In an imaging experiment with an integrating sphere light source and rotatable polarizer, the polarization imaging transmission model is verified and analysed for two cases of natural light and linearly polarized light incidence. Although the results indicate that the theoretical model is consistent with the experimental results, the theoretical model distinctly differs from the traditional paraxial approximation model. The results prove the accuracy and necessity of the theoretical model and the theoretical guiding significance for theoretical and systematic research of large field polarization imaging.

  6. Incidence of tuberculosis in and around Banglore

    Directory of Open Access Journals (Sweden)

    K. L. Phaniraja


    Full Text Available Incidence of Tuberculosis is higher in developing countries due to absence of National control and Eradication programme. Incidence is higher due to close contact with infected animal or human being. In the present study, 2668 bovines were screened for tuberculosis by single intradermal test from 15 different organized government and private farm. Currently, the SID test is used worldwide to determine whether an animal is sensitized to Mycobacterial antigens or not and the test is approved by OIE. Out of which, incidence of 2.89% in HF cross breeds, 0.69% in Jersey cross bred animals and none were shown reactor to Single Intradermal test in Indigenous animals. The higher incidence of 3.26% was found in female and 0.48% found in male. The calves which were below two year of age were found 1.56% reactor. [Vet World 2010; 3(4.000: 161-164

  7. Kentucky's highway incident management strategic plan. (United States)


    Kentucky s Highway Incident Management Strategic Plan consists of a mission statement, 4 goals, 16 objectives, and 49 action strategies. The action strategies are arranged by priority and recommended time frame for implementation. When implemented...

  8. USFA NFIRS 2000 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 2000 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  9. USFA NFIRS 2002 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 2002 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  10. USFA NFIRS 2004 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 2004 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  11. Oil Spill Incident Tracking [ds394 (United States)

    California Department of Resources — The Office of Spill Prevention and Response (OSPR) Incident Tracking Database is a statewide oil spill tracking information system. The data are collected by OSPR...

  12. National Fire Incident Reporting System (NFIRS) (United States)

    Department of Homeland Security — The National Fire Incident Reporting System (NFIRS) is a reporting standard that fire departments use to uniformly report on the full range of their activities, from...

  13. USFA NFIRS 2009 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 2009 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  14. Oil Spill Incident Tracking [ds394 (United States)

    California Natural Resource Agency — The Office of Spill Prevention and Response (OSPR) Incident Tracking Database is a statewide oil spill tracking information system. The data are collected by OSPR...

  15. Modelling and Simulation for Major Incidents

    Directory of Open Access Journals (Sweden)

    Eleonora Pacciani


    Full Text Available In recent years, there has been a rise in Major Incidents with big impact on the citizens health and the society. Without the possibility of conducting live experiments when it comes to physical and/or toxic trauma, only an accurate in silico reconstruction allows us to identify organizational solutions with the best possible chance of success, in correlation with the limitations on available resources (e.g. medical team, first responders, treatments, transports, and hospitals availability and with the variability of the characteristic of event (e.g. type of incident, severity of the event and type of lesions. Utilizing modelling and simulation techniques, a simplified mathematical model of physiological evolution for patients involved in physical and toxic trauma incident scenarios has been developed and implemented. The model formalizes the dynamics, operating standards and practices of medical response and the main emergency service in the chain of emergency management during a Major Incident.

  16. Rising incidence of Merkel cell carcinoma

    DEFF Research Database (Denmark)

    Lyhne, Dorte; Lock-Andersen, Jørgen; Dahlstrøm, Karin


    Abstract Merkel cell carcinoma (MCC) is a rare, aggressive, skin cancer of obscure histogenesis, the incidence of which is rising. There is no consensus on the optimal treatment. Our aim was to evaluate the staging, investigation, treatment, and follow-up of MCC in eastern Denmark......, and to investigate the incidence. We suggest guidelines for treatment. First we reviewed the medical records of 51 patients diagnosed with MCC from 1995 until 2006 in eastern Denmark. The nation-wide incidence of MCC was extracted from the Danish Cancer Registry for the calculations for the period 1986-2003. We...... reviwed published papers about MCC based on a MEDLINE search. Fourteen of the 51 patients developed recurrence, and 37 (73%) died during the study period. Mean follow-up was 13 months (range 1-122). A total of 153 patients were identified in the Danish Cancer Registry, and showed that incidence rates had...

  17. USFA NFIRS 2001 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 2001 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  18. USFA NFIRS 2003 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 2003 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  19. USFA NFIRS 1999 Basic Fire Incident Data (United States)

    Department of Homeland Security — The 1999 US Fire Administration Fire (USFA) Fire Incident & Cause Data was provided by the U.S. Fire Administration's (USFA) National Fire Data Center's (NFDC's)...

  20. Accuracies Of Optical Processors For Adaptive Optics (United States)

    Downie, John D.; Goodman, Joseph W.


    Paper presents analysis of accuracies and requirements concerning accuracies of optical linear-algebra processors (OLAP's) in adaptive-optics imaging systems. Much faster than digital electronic processor and eliminate some residual distortion. Question whether errors introduced by analog processing of OLAP overcome advantage of greater speed. Paper addresses issue by presenting estimate of accuracy required in general OLAP that yields smaller average residual aberration of wave front than digital electronic processor computing at given speed.

  1. Incident analysis for the large reprocessing plant

    International Nuclear Information System (INIS)

    Avenhaus, R.; Nagel, K.


    In the report period the analysis of important incidents in the extraction area has been started in caloboration with WAK (= Karlsruhe Reprocessing Plant) representatives. Ignition sources, ignitable substances, possible fires and the possible propagation of these fires within and beyond the cells were reviewed. The detailed analysis for a special incident was started. A fault tree was constructed for the conditions leading to an oxyhydrogen explosion in the 2 BX battery. (orig./RW) [de

  2. Wrong-patient incidents during medication administrations. (United States)

    Härkänen, Marja; Tiainen, Maijaterttu; Haatainen, Kaisa


    To describe the factors pertaining to medication being administered to the wrong patient and to describe how patient identification is mentioned in wrong-patient incident reports. Although patient identification has been given high priority to improve patient safety, patient misidentifications occur, and wrong-patient incidents are common. A descriptive content analysis. Incident reports related to medication administration (n = 1,012) were collected from two hospitals in Finland between 1 January 2013-31 December 2014. Of those, only incidents involving wrong-patient medication administration (n = 103) were included in this study. Wrong-patient incidents occurred due for many reasons, including nurse-related factors (such as tiredness, a lack of skills or negligence) but also system-related factors (such as rushing or heavy workloads). In 77% (n = 79) of wrong-patient incident reports, the process of identifying of the patient was not described at all. There is need to pay more attention to and increase training in correct identification processes to prevent wrong-patient incidents, and it is important to adjust system factors to support nurses. Active patient identification procedures, double-checking and verification at each stage of the medication process should be implemented. More attention should also be paid to organisational factors, such as division of work, rushing and workload, as well as to correct communication. The active participation of nurses in handling incidents could increase risk awareness and facilitate useful protection actions. © 2017 John Wiley & Sons Ltd.

  3. Blindness incidence in Germany. A population-based study from Württemberg-Hohenzollern. (United States)

    Krumpaszky, H G; Lüdtke, R; Mickler, A; Klauss, V; Selbmann, H K


    Few data on the incidence of blindness in Germany are available. We analysed causes of legal blindness for the region Württemberg-Hohenzollern (population 5.5 million) in order to help fill in this gap. Population-based investigation on the incidence of legal blindness (visual acuity <1/50) based on materials from the social services. Age-dependent blindness incidences were modelled via logistic regression models. 647 blind persons were newly registered in 1994 (blindness incidence 11.6/100,000). The blindness incidence is moderate in infants (4.5/100,000) and decreases further during childhood. At the age of 20 years, the incidence again rises to the former level and remains relatively constant. After the age of 60 years, the incidence increases sharply: 5-year odds ratios are 1.76 (CI: 1.68-1. 85) in women and 1.72 (CI: 1.60-1.84) in men. The blindness incidence is higher in women, 15.6/100,000, compared to 12.2/100,000 in men. The major causes of blindness are: macular degeneration, 3. 92/100,000; diabetic retinopathy, 2.01/100,000; glaucoma, 1.6/100, 000; high myopia, 0.77/100,000; optic atrophy, 0.68/100,000; central nervous system-triggered blindness; 0.56/100,000, and tapetoretinal degenerations, 0.52/100,000. Due to monetary incentives for the blind persons, social service files offer accurate and complete data. Besides macular degeneration, glaucoma and diabetic retinopathy are major causes of blindness. Thus, this study suggests further blindness prevention activities for diabetic retinopathy and glaucoma.

  4. NEA incident reporting system: Three years' experience

    International Nuclear Information System (INIS)

    Otsuka, Y.; Haeussermann, W.


    The paper presents an overview of the NEA Incident Reporting System (IRS) which was set up to collect, assess and disseminate on safety-related incidents in nuclear power plants. The IRS information exchange is significant in two senses. First, it enables regulatory authorities and utilities in participating countries to take appropriate action to prevent the reported mishaps occurring again elsewhere. Secondly, the continuous collection and systematic analysis of such information allows identification of areas of concern where safety research should be strengthened. There are two stages in the IRS information exchange. First, the national IRS Co-ordinator selects information on significant incidents, in accordance with a common reporting threshold, from the abnormal occurrences reported to the regulatory body, to be distributed through the NEA Secretariat. This screening is intended to exclude minor events, so that only significant information is sent to participating countries. Secondly, a group of experts periodically reviews the incidents reported during the preceding twelve months to identify major areas of concern. To assist this process, a computer-based data retrieval system is being developed for IRS incident reports. The paper gives some details of the IRS mechanism and discusses reporting criteria and the information included in a report. Areas of concern derived from reported incidents, an outline of the data retrieval system, and examples of feedback of lessons learned and possibilities for international co-operation are also discussed. (author)

  5. Serious incidents after death: content analysis of incidents reported to a national database. (United States)

    Yardley, Iain E; Carson-Stevens, Andrew; Donaldson, Liam J


    Objectives To describe serious incidents occurring in the management of patient remains after their death. Design Incidents occurring after patient deaths were analysed using content analysis to determine what happened, why it happened and the outcome. Setting The Strategic Executive Information System database of serious incidents requiring investigation occurring in the National Health Service in England. Participants All cases describing an incident that occurred following death, regardless of the age of the patient. Main outcome measures The nature of the incident, the underlying cause or causes of the incident and the outcome of the incident. Results One hundred and thirty-two incidents were analysed; these related to the storage, management or disposal of deceased patient remains. Fifty-four incidents concerned problems with the storage of bodies or body parts. Forty-three incidents concerned problems with the management of bodies, including 25 errors in postmortem examination, or postmortems on the wrong body. Thirty-one incidents related to the disposal of bodies, 25 bodies were released from the mortuary to undertakers in error; of these, nine were buried or cremated by the wrong family. The reported underlying causes were similar to those known to be associated with safety incidents occurring before death and included weaknesses in or failures to follow protocol and procedure, poor communication and informal working practices. Conclusions Serious incidents in the management of deceased patient remains have significant implications for families, hospitals and the health service more broadly. Safe mortuary care may be improved by applying lessons learned from existing patient safety work.

  6. Test facility for astronomical x-ray optics

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Lewis, Robert A.; Bordas, J.


    Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earth's atmosphere. These devices require a large collection aperture and the imaging of an x-ray source that is essentially placed at infinity. The ideal testing system for these optical elements has to appro......Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earth's atmosphere. These devices require a large collection aperture and the imaging of an x-ray source that is essentially placed at infinity. The ideal testing system for these optical elements has...... to approximate that encountered under working conditions; however, the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area while still retaining...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes, is described. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  7. Fibre-optical microendoscopy. (United States)

    Gu, M; Bao, H; Kang, H


    Microendoscopy has been an essential tool in exploring micro/nano mechanisms in vivo due to high-quality imaging performance, compact size and flexible movement. The investigations into optical fibres, micro-scanners and miniature lens have boosted efficiencies of remote light delivery to sample site and signal collection. Given the light interaction with materials in the fluorescence imaging regime, this paper reviews two classes of compact microendoscopy based on a single fibre: linear optical microendoscopy and nonlinear optical microendoscopy. Due to the fact that fluorescence occurs only in the focal volume, nonlinear optical microendoscopy can provide stronger optical sectioning ability than linear optical microendoscopy, and is a good candidate for deep tissue imaging. Moreover, one-photon excited fluorescence microendoscopy as the linear optical microendoscopy suffers from severe photobleaching owing to the linear dependence of photobleaching rate on excitation laser power. On the contrary, nonlinear optical microendoscopy, including two-photon excited fluorescence microendoscopy and second harmonic generation microendoscopy, has the capability to minimize or avoid the photobleaching effect at a high excitation power and generate high image contrast. The combination of various nonlinear signals gained by the nonlinear optical microendoscopy provides a comprehensive insight into biophenomena in internal organs. Fibre-optical microendoscopy overcomes physical limitations of traditional microscopy and opens up a new path to achieve early cancer diagnosis and microsurgery in a minimally invasive and localized manner. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  8. Comparative Incidence of Conformational, Neurodegenerative Disorders.

    Directory of Open Access Journals (Sweden)

    Jesús de Pedro-Cuesta

    Full Text Available The purpose of this study was to identify incidence and survival patterns in conformational neurodegenerative disorders (CNDDs.We identified 2563 reports on the incidence of eight conditions representing sporadic, acquired and genetic, protein-associated, i.e., conformational, NDD groups and age-related macular degeneration (AMD. We selected 245 papers for full-text examination and application of quality criteria. Additionally, data-collection was completed with detailed information from British, Swedish, and Spanish registries on Creutzfeldt-Jakob disease (CJD forms, amyotrophic lateral sclerosis (ALS, and sporadic rapidly progressing neurodegenerative dementia (sRPNDd. For each condition, age-specific incidence curves, age-adjusted figures, and reported or calculated median survival were plotted and examined.Based on 51 valid reported and seven new incidence data sets, nine out of eleven conditions shared specific features. Age-adjusted incidence per million person-years increased from ≤1.5 for sRPNDd, different CJD forms and Huntington's disease (HD, to 1589 and 2589 for AMD and Alzheimer's disease (AD respectively. Age-specific profiles varied from (a symmetrical, inverted V-shaped curves for low incidences to (b those increasing with age for late-life sporadic CNDDs and for sRPNDd, with (c a suggested, intermediate, non-symmetrical inverted V-shape for fronto-temporal dementia and Parkinson's disease. Frequently, peak age-specific incidences from 20-24 to ≥90 years increased with age at onset and survival. Distinct patterns were seen: for HD, with a low incidence, levelling off at middle age, and long median survival, 20 years; and for sRPNDd which displayed the lowest incidence, increasing with age, and a short median disease duration.These results call for a unified population view of NDDs, with an age-at-onset-related pattern for acquired and sporadic CNDDs. The pattern linking age at onset to incidence magnitude and survival might

  9. Generalized nihility media from transformation optics

    International Nuclear Information System (INIS)

    Yan, Wei; Yan, Min; Qiu, Min


    Nihility media in the previous literature are usually understood as media with ε = μ = 0. Transformation optics opens a new perspective for capturing the essence of such media. From this perspective, we generalize the definition of nihility media as transformation media derived from volumeless geometrical elements. A volumeless geometrical elements can be either a point (P), a line (L), or a surface (S). Their corresponding transformation media are therefore called P-, L-, or S-type nihility media, respectively. The previous defined nihility media with ε = μ = 0 is a special case under the P-type nihility media. The constructions of nihility media by metamaterials are discussed. The eigenfields in different types of nihility media are derived. The interactions between an externally incident wave and a slab of nihility media in a free space background are analyzed. Furthermore, we discuss compensated bilayers composed of nihility media. It is shown that for a slab of P-type nihility media, a normally incident wave can perfectly transmit through, while all obliquely incident waves are completely blocked; for a slab made of L-type nihility media, both normally and obliquely incident waves can transmit with some reflections, which can be eliminated by adding a compensating L-type nihility media; for a slab of S-type nihility media, all field components can perfectly transmit through

  10. Clinical incidents involving students on placement: an analysis of incident reports to identify potential risk factors. (United States)

    Gaida, J E; Maloney, S; Lo, K; Morgan, P


    Students are sometimes involved in incidents during clinical training. To the authors' knowledge, no quantitative studies of incidents specifically involving physiotherapy students on clinical placement are available in the literature. A retrospective audit (2008 to 2011) of incident reports involving physiotherapy students was conducted to identify the nature and features of incidents. The study aimed to determine if injuries to a student or patient were more or less likely when the supervisor was in close proximity, and whether students with lower academic performance in their preclinical semester were more likely to be involved in an incident. There were 19 care-delivery-related and three equipment-related incidents. There were no incidents of violent, aggressive or demeaning behaviour towards students. The incident rate was 9.0/100,000 student-hours for third-year students and 6.8/100,000 student-hours for fourth-year students. The majority of incidents (55%) occurred from 11 am to 12-noon and from 3 pm to 3.30 pm. Incidents more often resulted in patient or student injury when the supervisor was not in close proximity (approximately 50% vs approximately 20%), although the difference was not significant (P=0.336). The academic results of students involved in incidents were equivalent to the whole cohort in their preclinical semester {mean 75 [standard deviation (SD) 6] vs 76 (SD 7); P=0.488}. The unexpected temporal clustering of incidents warrants further investigation. Student fatigue may warrant attention as a potential contributor; however, contextual factors, such as staff workload, along with organisational systems, structures and procedures may be more relevant. The potential relationship between supervisor proximity and injury also warrants further exploration. The findings of the present study should be integrated into clinical education curricula and communicated to clinical educators. Copyright © 2014 Chartered Society of Physiotherapy. Published by

  11. Tuberculosis incidence in prisons: a systematic review. (United States)

    Baussano, Iacopo; Williams, Brian G; Nunn, Paul; Beggiato, Marta; Fedeli, Ugo; Scano, Fabio


    Transmission of tuberculosis (TB) in prisons has been reported worldwide to be much higher than that reported for the corresponding general population. A systematic review has been performed to assess the risk of incident latent tuberculosis infection (LTBI) and TB disease in prisons, as compared to the incidence in the corresponding local general population, and to estimate the fraction of TB in the general population attributable (PAF%) to transmission within prisons. Primary peer-reviewed studies have been searched to assess the incidence of LTBI and/or TB within prisons published until June 2010; both inmates and prison staff were considered. Studies, which were independently screened by two reviewers, were eligible for inclusion if they reported the incidence of LTBI and TB disease in prisons. Available data were collected from 23 studies out of 582 potentially relevant unique citations. Five studies from the US and one from Brazil were available to assess the incidence of LTBI in prisons, while 19 studies were available to assess the incidence of TB. The median estimated annual incidence rate ratio (IRR) for LTBI and TB were 26.4 (interquartile range [IQR]: 13.0-61.8) and 23.0 (IQR: 11.7-36.1), respectively. The median estimated fraction (PAF%) of tuberculosis in the general population attributable to the exposure in prisons for TB was 8.5% (IQR: 1.9%-17.9%) and 6.3% (IQR: 2.7%-17.2%) in high- and middle/low-income countries, respectively. The very high IRR and the substantial population attributable fraction show that much better TB control in prisons could potentially protect prisoners and staff from within-prison spread of TB and would significantly reduce the national burden of TB. Future studies should measure the impact of the conditions in prisons on TB transmission and assess the population attributable risk of prison-to-community spread. Please see later in the article for the Editors' Summary.

  12. An inexpensive high-temperature optical fiber thermometer

    International Nuclear Information System (INIS)

    Moore, Travis J.; Jones, Matthew R.; Tree, Dale R.; Allred, David D.


    An optical fiber thermometer consists of an optical fiber whose tip is coated with a highly conductive, opaque material. When heated, this sensing tip becomes an isothermal cavity that emits like a blackbody. This emission is used to predict the sensing tip temperature. In this work, analytical and experimental research has been conducted to further advance the development of optical fiber thermometry. An inexpensive optical fiber thermometer is developed by applying a thin coating of a high-temperature cement onto the tip of a silica optical fiber. An FTIR spectrometer is used to detect the spectral radiance exiting the fiber. A rigorous mathematical model of the irradiation incident on the detection system is developed. The optical fiber thermometer is calibrated using a blackbody radiator and inverse methods are used to predict the sensing tip temperature when exposed to various heat sources. - Highlights: • An inexpensive coating for an optical fiber thermometer sensing tip is tested. • Inverse heat transfer methods are used to estimate the sensing tip temperature. • An FTIR spectrometer is used as the detector to test the optical fiber thermometer using various heat sources.

  13. Advances in integrated optics

    CERN Document Server

    Chester, A; Bertolotti, M


    This volwne contains the Proceedings of a two-week summer conference titled "Advances in Integrated Optics" held June 1-9, 1993, in Erice, Sicily. This was the 18th annual course organized by the International School of Quantum Electronics, under the auspices of the "Ettore Majorana" Centre for Scientific Culture. The term Integrated Optics signifies guided-wave optical circuits consisting of two or more devices on a single substrate. Since its inception in the late 1960's, Integrated Optics has evolved from a specialized research topic into a broad field of work, ranging from basic research through commercial applications. Today many devices are available on market while a big effort is devolved to research on integrated nonlinear optical devices. This conference was organized to provide a comprehensive survey of the frontiers of this technology, including fundamental concepts, nonlinear optical materials, devices both in the linear and nonlinear regimes, and selected applications. These Proceedings update a...

  14. Silicon Optical Modulator Simulation

    Directory of Open Access Journals (Sweden)

    Soon Thor LIM


    Full Text Available We developed a way of predicting and analyzing high speed optical modulator. Our research adopted a bottom-up approach to consider high-speed optical links using an eye diagram. Our method leverages on modular mapping of electrical characteristics to optical characteristics, while attaining the required accuracy necessary for device footprint approaching sub-micron scales where electrical data distribution varies drastically. We calculate for the bias dependent phase shift (2pi/mm and loss (dB/mm for the optical modulator based on the real and imaginary part of complex effective indices. Subsequently, combine effectively both the electrical and optical profiles to construct the optical eye diagram which is the essential gist of signal integrity of such devices.

  15. Fundamentals of optical waveguides

    CERN Document Server

    Okamoto, Katsunari


    Fundamentals of Optical Waveguides is an essential resource for any researcher, professional or student involved in optics and communications engineering. Any reader interested in designing or actively working with optical devices must have a firm grasp of the principles of lightwave propagation. Katsunari Okamoto has presented this difficult technology clearly and concisely with several illustrations and equations. Optical theory encompassed in this reference includes coupled mode theory, nonlinear optical effects, finite element method, beam propagation method, staircase concatenation method, along with several central theorems and formulas. Since the publication of the well-received first edition of this book, planar lightwave circuits and photonic crystal fibers have fully matured. With this second edition the advances of these fibers along with other improvements on existing optical technologies are completely detailed. This comprehensive volume enables readers to fully analyze, design and simulate opti...

  16. Lasers and optical engineering

    CERN Document Server

    Das, P


    A textbook on lasers and optical engineering should include all aspects of lasers and optics; however, this is a large undertaking. The objective of this book is to give an introduction to the subject on a level such that under­ graduate students (mostly juniors/seniors), from disciplines like electrical engineering, physics, and optical engineering, can use the book. To achieve this goal, a lot of basic background material, central to the subject, has been covered in optics and laser physics. Students with an elementary knowledge of freshman physics and with no formal courses in electromagnetic theory should be able to follow the book, although for some sections, knowledge of electromagnetic theory, the Fourier transform, and linear systems would be highly beneficial. There are excellent books on optics, laser physics, and optical engineering. Actually, most of my knowledge was acquired through these. However, when I started teaching an undergraduate course in 1974, under the same heading as the title of th...

  17. Tunable micro-optics

    CERN Document Server

    Duppé, Claudia


    Presenting state-of-the-art research into the dynamic field of tunable micro-optics, this is the first book to provide a comprehensive survey covering a varied range of topics including novel materials, actuation concepts and new imaging systems in optics. Internationally renowned researchers present a diverse range of chapters on cutting-edge materials, devices and subsystems, including soft matter, artificial muscles, tunable lenses and apertures, photonic crystals, and complete tunable imagers. Special contributions also provide in-depth treatment of micro-optical characterisation, scanners, and the use of natural eye models as inspiration for new concepts in advanced optics. With applications extending from medical diagnosis to fibre telecommunications, Tunable Micro-optics equips readers with a solid understanding of the broader technical context through its interdisciplinary approach to the realisation of new types of optical systems. This is an essential resource for engineers in industry and academia,...

  18. Optical design of a LED searchlight system (United States)

    Gong, Chen; Xu, Haiping; Liang, Jinhua; Liu, Yunfei; Yuan, Zengquan


    A 1200m visible searchlight system is designed based on photometry and application of geometric optics. To generate intensity distribution of this relatively powerful light beam we propose to use a high power LED and several refractive optical elements, which are composed of two plane-convex lenses and a conventional Fresnel lens. Two plane-convex lenses enable refraction of the side rays from the LED to the front direction which incident on the Fresnel lens. Fresnel lens, in its turn, concentrate the light flux and provide a nearly collimated beam to meet the requirement of forming a well-illuminated area across the road in the far field. Simulation data shows that this searchlight allow generating an appropriate illumination distribution for the long range requirements. A proof-of-concept prototype producing acceptable illuminance is developed.

  19. Progress in optics

    CERN Document Server

    Wolf, Emil


    In the fourty-six years that have gone by since the first volume of Progress in Optics was published, optics has become one of the most dynamic fields of science. The volumes in this series which have appeared up to now contain more than 300 review articles by distinguished research workers, which have become permanent records for many important developments.- Metamaterials- Polarization Techniques- Linear Baisotropic Mediums- Ultrafast Optical Pulses- Quantum Imaging- Point-Spread Funcions- Discrete Wigner Functions

  20. Optical atomic magnetometer (United States)

    Budker, Dmitry; Higbie, James; Corsini, Eric P


    An optical atomic magnetometers is provided operating on the principles of nonlinear magneto-optical rotation. An atomic vapor is optically pumped using linearly polarized modulated light. The vapor is then probed using a non-modulated linearly polarized light beam. The resulting modulation in polarization angle of the probe light is detected and used in a feedback loop to induce self-oscillation at the resonant frequency.

  1. Dominant optic atrophy

    DEFF Research Database (Denmark)

    Lenaers, Guy; Hamel, Christian; Delettre, Cécile


    DEFINITION OF THE DISEASE: Dominant Optic Atrophy (DOA) is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC) an......) and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain....

  2. Concepts of classical optics

    CERN Document Server

    Strong, John


    An intermediate course in optics, this volume explores both experimental and theoretical concepts, offering practical knowledge of geometrical optics that will enhance students' comprehension of any relevant applied science. Its exposition of the concepts of classical optics is presented with a minimum of mathematical detail but presumes some knowledge of calculus, vectors, and complex numbers.Subjects include light as wave motion; superposition of wave motions; electromagnetic waves; interaction of light and matter; velocities and scattering of light; polarized light and dielectric boundarie

  3. Optical Fibre Bundle

    CERN Multimedia

    These are sample fibre optic cables which are used for networking. Optical fibers are widely used in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data rates) than wire cables. Fibers are used instead of metal wires because signals travel along them with less loss and are also immune to electromagnetic interference. This is useful for somewhere like CERN where magnets with their highly powerful magnetic fields could pose a problem.

  4. How to Report a Pesticide Incident Involving Exposures to People (United States)

    Pesticides incidents must be reported by pesticide registrants. Others, such as members of the public and environmental professionals, would like to report pesticide incidents. This website will facilitate such incident reporting.

  5. Assembling optically active and nonactive metamaterials with chiral units

    Directory of Open Access Journals (Sweden)

    Xiang Xiong


    Full Text Available Metamaterials constructed with chiral units can be either optically active or nonactive depending on the spatial configuration of the building blocks. For a class of chiral units, their effective induced electric and magnetic dipoles, which originate from the induced surface electric current upon illumination of incident light, can be collinear at the resonant frequency. This feature provides significant advantage in designing metamaterials. In this paper we concentrate on several examples. In one scenario, chiral units with opposite chiralities are used to construct the optically nonactive metamaterial structure. It turns out that with linearly polarized incident light, the pure electric or magnetic resonance (and accordingly negative permittivity or negative permeability can be selectively realized by tuning the polarization of incident light for 90°. Alternatively, units with the same chirality can be assembled as a chiral metamaterial by taking the advantage of the collinear induced electric and magnetic dipoles. It follows that for the circularly polarized incident light, negative refractive index can be realized. These examples demonstrate the unique approach to achieve certain optical properties by assembling chiral building blocks, which could be enlightening in designing metamaterials.

  6. Determination of optical constants and nonlinear optical coefficients ...

    Indian Academy of Sciences (India)

    −7 cm2/W and nonlinear absorption coefficient, β = 6.31×10. −3 cm/W. Optical limiting characteris- tics of the dye-doped polymer film was studied. The result reveals that Violet 1 can be a promising material for optical limiting applications. Keywords. Absorption spectra; nonlinear optics; optical constants; optical limiting.

  7. Overview of optical microscopy and optical microspectroscopy (United States)

    Ager, Joel W.


    Optical microscopy has historically been a major tool for semiconductor inspection. As the ULSI design rule continues to decline to 0.25 μm and below, standard optical microscopy methods will arrive at their resolution limit. In the first part of this paper an overview of currently used optical microscopy techniques will be given. The resolution limit for optical imaging will be discussed, and novel methods for increasing resolution, including deep UV microscopy and confocal laser microscopy, will be presented. The second part of the paper will discuss an emerging technology for contamination analysis in semiconductor processing, microspectroscopy. Three topics in this area will be discussed with an emphasis on applications to off-line defect identification in process development: (1) micro-Raman spectroscopy, (2) micro-fluorescence or micro-photoluminescence spectroscopy, and (3) micro-reflectivity. It will be shown that these microspectroscopy methods can provide composition information for defects down to 1 μm in size that is not accessible through the more commonly used methods such as scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) and scanning Auger microscopy. Classes of defects where optical micro-spectroscopy methods are useful include ceramic particles, thin films of organic material, and dielectric films.

  8. LSST Camera Optics Design

    Energy Technology Data Exchange (ETDEWEB)

    Riot, V J; Olivier, S; Bauman, B; Pratuch, S; Seppala, L; Gilmore, D; Ku, J; Nordby, M; Foss, M; Antilogus, P; Morgado, N


    The Large Synoptic Survey Telescope (LSST) uses a novel, three-mirror, telescope design feeding a camera system that includes a set of broad-band filters and three refractive corrector lenses to produce a flat field at the focal plane with a wide field of view. Optical design of the camera lenses and filters is integrated in with the optical design of telescope mirrors to optimize performance. We discuss the rationale for the LSST camera optics design, describe the methodology for fabricating, coating, mounting and testing the lenses and filters, and present the results of detailed analyses demonstrating that the camera optics will meet their performance goals.

  9. Optics for engineers

    CERN Document Server

    DiMarzio, Charles A


    This book is an excellent resource for teaching any student or scientist who needs to use optical systems. I particularly like the addition of MATLAB scripts and functions. Highly recommended.-Professor James C. Wyant, Dean of College of Optical Sciences, University of ArizonaHis book is clear, concise and highly readable. This is an excellent text.-Professor Changhuei Yang, California Institute of TechnologyAt last, a book on optics that is written with the practising engineer in mind. I have been teaching optics to engineers for many years and have often longed for a text aimed at my student

  10. Interactive virtual optical laboratories (United States)

    Liu, Xuan; Yang, Yi


    Laboratory experiences are essential for optics education. However, college students have limited access to advanced optical equipment that is generally expensive and complicated. Hence there is a need for innovative solutions to expose students to advanced optics laboratories. Here we describe a novel approach, interactive virtual optical laboratory (IVOL) that allows unlimited number of students to participate the lab session remotely through internet, to improve laboratory education in photonics. Although students are not physically conducting the experiment, IVOL is designed to engage students, by actively involving students in the decision making process throughout the experiment.

  11. Ocean Optics Instrumentation Systems (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation suites for a wide variety of measurements to characterize the ocean’s optical environment. These packages have been developed to...

  12. Optical engineering of diamond

    CERN Document Server

    Rabeau, James R


    This is the first comprehensive book on the engineering of diamond optical devices. It will give readers an up-to-date account of the properties of optical quality synthetic diamond (single crystal, nanodiamond and polycrystalline) and reviews the large and growing field of engineering of diamond-based optical devices, with applications in quantum computation, nano-imaging, high performance lasers, and biomedicine. It aims to provide scientists, engineers and physicists with a valuable resource and reference book for the design and performance of diamond-based optical devices.

  13. Bidirectional optical scattering facility (United States)

    Federal Laboratory Consortium — Goniometric optical scatter instrument (GOSI)The bidirectional reflectance distribution function (BRDF) quantifies the angular distribution of light scattered from a...

  14. Optics, light and lasers

    CERN Document Server

    Meschede, Dieter


    Starting from the concepts of classical optics, Optics, Light and Lasers introduces in detail the phenomena of linear and nonlinear light matter interaction, the properties of modern laser sources, and the concepts of quantum optics. Several examples taken from the scope of modern research are provided to emphasize the relevance of optics in current developments within science and technology. The text has been written for newcomers to the topic and benefits from the author's ability to explain difficult sequences and effects in a straightforward and easily comprehensible way. To this second, c

  15. Elementary wave optics

    CERN Document Server

    Webb, Robert H


    This undergraduate textbook presents thorough coverage of the standard topics of classical optics and optical instrument design; it also offers significant details regarding the concepts of modern optics. Its survey of the mathematical tools of optics grants students insights into the physical principles of quantum mechanics.Two principal concepts occur throughout: a treatment of scattering from real scatterers (leading to Huygens' principles, diffraction theory, the index of refraction, and related topics); and the difference between coherent and noncoherent wave phenomena. Examinations of su

  16. Optically pumped atoms

    CERN Document Server

    Happer, William; Walker, Thad


    Covering the most important knowledge on optical pumping of atoms, this ready reference is backed by numerous examples of modelling computation for optical pumped systems. The authors show for the first time that modern scientific computing software makes it practical to analyze the full, multilevel system of optically pumped atoms. To make the discussion less abstract, the authors have illustrated key points with sections of MATLAB codes. To make most effective use of contemporary mathematical software, it is especially useful to analyze optical pumping situations in the Liouville spa

  17. Optical network democratization. (United States)

    Nejabati, Reza; Peng, Shuping; Simeonidou, Dimitra


    The current Internet infrastructure is not able to support independent evolution and innovation at physical and network layer functionalities, protocols and services, while at same time supporting the increasing bandwidth demands of evolving and heterogeneous applications. This paper addresses this problem by proposing a completely democratized optical network infrastructure. It introduces the novel concepts of the optical white box and bare metal optical switch as key technology enablers for democratizing optical networks. These are programmable optical switches whose hardware is loosely connected internally and is completely separated from their control software. To alleviate their complexity, a multi-dimensional abstraction mechanism using software-defined network technology is proposed. It creates a universal model of the proposed switches without exposing their technological details. It also enables a conventional network programmer to develop network applications for control of the optical network without specific technical knowledge of the physical layer. Furthermore, a novel optical network virtualization mechanism is proposed, enabling the composition and operation of multiple coexisting and application-specific virtual optical networks sharing the same physical infrastructure. Finally, the optical white box and the abstraction mechanism are experimentally evaluated, while the virtualization mechanism is evaluated with simulation. © 2016 The Author(s).

  18. Integrating incident investigation into the management system

    International Nuclear Information System (INIS)

    Peterson, E.E.


    In the last 10 yr, the size and frequency of incidents affecting the communities and environment surrounding chemical processing facilities has increased. The chemical process industry, which has always concerned itself with the safety of its facilities, has responded by committing to stricter standards of operation and management. A critical element of these management practices is the use of a structured incident investigation program. Many facilities have implemented and disciplined themselves to perform good investigation of incidents. However, most of these facilities maintain incident investigation as part of their safety management programs. This allows the process to be disconnected from the management system that deals with the day-to-day business of the facility. The first step of integration is understanding the objectives and functions of the management system into which the integration is to occur. To begin, a common definition of management is needed. Management, for the purposes of this discussion, is defined as the system of activities used to control, coordinate, and improve the flow of work within a facility or organization. This definition refers to several concepts that need further development in order to understand how incident investigation can be integrated into a management system, including (a) flow of work, (b) control, and (c) improvement. Application can be made to the nuclear industry

  19. Incidence and epidemiology of tibial shaft fractures

    DEFF Research Database (Denmark)

    Larsen, Peter; Elsøe, Rasmus; Hansen, Sandra Hope


    Introduction: The literature lacks recent population-based epidemiology studies of the incidence, trauma mechanism and fracture classification of tibial shaft fractures. The purpose of this study was to provide up-to-date information on the incidence of tibial shaft fractures in a large and compl......Introduction: The literature lacks recent population-based epidemiology studies of the incidence, trauma mechanism and fracture classification of tibial shaft fractures. The purpose of this study was to provide up-to-date information on the incidence of tibial shaft fractures in a large...... the highest frequency between the age of 30 and 40. AO-type 42-A1 was the most common fracture type, representing 34% of all tibial shaft fractures. The majority of tibial shaft fractures occur during walking, indoor activity and sports. The distribution among genders shows that males present a higher...... frequency of fractures while participating in sports activities and walking. Women present the highest frequency of fractures while walking and during indoor activities. Conclusion: This study shows an incidence of 16.9/100,000/year for tibial shaft fractures. AO-type 42-A1 was the most common fracture type...

  20. Incidence and overall survival of malignant ameloblastoma. (United States)

    Rizzitelli, Alexandra; Smoll, Nicolas R; Chae, Michael P; Rozen, Warren M; Hunter-Smith, David J


    Malignant ameloblastoma, comprising metastasizing ameloblastoma and ameloblastic carcinoma, represents 1.6-2.2% of all odontogenic tumors. Due to its rare nature, malignant ameloblastoma has only been reported in the literature in small case series or case reports. Using the Surveillance, Epidemiology and End-Results (SEER) database, we have performed a population-based study to determine the incidence rate and the absolute survival of malignant ameloblastoma. Using the International Classification of Diseases for Oncology (ICD-O) codes 9310/3 and 9270/3, data from the SEER database were used to calculate the incidence rate and absolute survival rate of population with malignant ameloblastoma. The overall incidence rate of malignant ameloblastoma was 1.79 per 10 million person/year. The incidence rate was higher in males than females and also higher in black versus white population. The median overall survival was 17.6 years from the time of diagnosis and increasing age was associated with a statistically significant poorer survival. To our best knowledge, we report the largest population-based series of malignant ameloblastoma. The incidence rate was 1.79 per 10 million person/year and the overall survival was 17.6 years.

  1. Incidence and overall survival of malignant ameloblastoma.

    Directory of Open Access Journals (Sweden)

    Alexandra Rizzitelli

    Full Text Available Malignant ameloblastoma, comprising metastasizing ameloblastoma and ameloblastic carcinoma, represents 1.6-2.2% of all odontogenic tumors. Due to its rare nature, malignant ameloblastoma has only been reported in the literature in small case series or case reports. Using the Surveillance, Epidemiology and End-Results (SEER database, we have performed a population-based study to determine the incidence rate and the absolute survival of malignant ameloblastoma.Using the International Classification of Diseases for Oncology (ICD-O codes 9310/3 and 9270/3, data from the SEER database were used to calculate the incidence rate and absolute survival rate of population with malignant ameloblastoma.The overall incidence rate of malignant ameloblastoma was 1.79 per 10 million person/year. The incidence rate was higher in males than females and also higher in black versus white population. The median overall survival was 17.6 years from the time of diagnosis and increasing age was associated with a statistically significant poorer survival.To our best knowledge, we report the largest population-based series of malignant ameloblastoma. The incidence rate was 1.79 per 10 million person/year and the overall survival was 17.6 years.

  2. Incidence of constipation in stroke patients (United States)

    Li, Jianxiang; Yuan, Mengguo; Liu, Yunfang; Zhao, Yang; Wang, Jingqing; Guo, Weifeng


    Abstract There is growing awareness of a link between the gut and cardiovascular disease. Constipation is common among individuals who have had a stroke, and it negatively affects social functioning and quality of life. However, no systematic study on the incidence of constipation in stroke patients has been reported. We selected studies included in Medline, Embase, Cochrane database, and Web of Science. Studies were included if they reported the incidence in stroke patients. Two authors selected the studies, extracted the data independently, and assessed these. Subgroup analyses were conducted according to the stroke subtype and stage of stroke. After detailed evaluations, 8 studies (n  =  1385 participants) were found that contained data that were suitable for meta-analytic synthesis. A forest plot showed that the incidence of constipation was 48% (95% confidence interval [CI]  =  33%–63%). In the analysis of the type of stroke subgroup, the incidence of constipation in patients who had had a hemorrhagic stroke (66% [95% CI  =  40–91%]) was higher than that in patients who had experienced an ischemic stroke (51% [95% CI  =  27%–75%]). The incidence in the acute stage (45% [95% CI  =  36%–54%]) was lower than that in the rehabilitation stage (48% [95% CI  =  23%–73%]). Constipation after a stroke event occurs frequently. This finding may raise awareness about bowel complications to allow correct evaluation and proper management. PMID:28640117

  3. Incidence and prevalence of psoriasis in Denmark

    DEFF Research Database (Denmark)

    Egeberg, Alexander; Skov, Lone; Gislason, Gunnar H.


    The incidence and temporal trends of psoriasis in Denmark between 2003 and 2012 were examined. There was a female predominance ranging between 50.0% (2007) and 55.4% (2009), and the mean age at time of diagnosis was 47.7-58.7 years. A total of 126,055 patients with psoriasis (prevalence 2.2%) were...... identified. Incidence rates of psoriasis (per 100,000 person years) ranged from 107.5 in 2005 to a peak incidence of 199.5 in 2010. Incidence rates were higher for women, and patients aged 60-69 years, respectively. Use of systemic non-biologic agents, i.e. methotrexate, cyclosporine, retinoids, or psoralen...... plus ultraviolet A (PUVA) increased over the study course, and were used in 15.0% of all patients. Biologic agents (efalizumab, etanercept, infliximab, adalimumab, or ustekinumab) were utilized in 2.7% of patients. On a national level, incidence of psoriasis fluctuated during the 10- year study course...

  4. Carbon sputtering yield measurements at grazing incidence

    International Nuclear Information System (INIS)

    Kolasinski, Robert D.; Polk, James E.; Goebel, Dan; Johnson, Lee K.


    In this investigation, carbon sputtering yields were measured experimentally at varying angles of incidence under Xe + bombardment. The measurements were obtained by etching a coated quartz crystal microbalance (QCM) with a low energy ion beam. The material properties of the carbon targets were characterized with a scanning electron microscope (SEM) and Raman spectroscopy. C sputtering yields measured under Ar + and Xe + bombardment at normal incidence displayed satisfactory agreement with previously published data over an energy range of 200 eV-1 keV. For Xe + ions, the dependence of the yields on angle of incidence θ was determined for 0 o ≤ θ ≤ 80 deg. Over this range, an increase in C sputtering yield by a factor of 4.8 was observed, with the peak in yield occurring at 70 o . This is a much higher variation compared to Xe + → Mo yields under similar conditions, a difference that may be attributed to higher scattering of the incident particles transverse to the beam direction than in the case of Xe + → C. In addition, the variation of the yields with θ was not strongly energy dependent. Trapping of Xe in the surface was observed, in contrast to observations using the QCM technique with metallic target materials. Finally, target surface roughness was characterized using atomic force microscope measurements to distinguish between the effects of local and overall angle of incidence of the target

  5. Time-dependent scattering of incident light of various wavelengths in ferrofluids under external magnetic field (United States)

    Jin, Jingyu; Song, Dongxing; Geng, Jiafeng; Jing, Dengwei


    Ferrofluids can exhibit the anisotropic thermodynamic properties under magnetic fields. The dynamic optical properties of ferrofluids in the presence of magnetic fields are of particular interest due to their potential application as various optical devices. Although time-dependent light scattering by ferrofluids have been extensively studied, the effect of wavelength of incident light have been rarely considered. Here, for the first time, we investigated both the time- and wavelength-dependent light scattering in water based ferrofluids containing Fe3O4 nanoparticles under an external magnetic field. The field-induced response behavior of the prepared ferrofluid samples was determined and verified first by thermal conductivity measurement and numerical simulation. Double-beam UV-Vis spectrophotometer was employed to record the temporal evolution of transmitted intensity of incident light of various wavelengths passing through the ferrofluid sample and propagating parallel to the applied field. As expected, the light intensity decreases to a certain value right after the field is turned on due to the thermal fluctuation induced disorder inside the flexible particle chains. Then the light intensity further decreases with time until the appearance of a minimum at time τ0 followed by an inversed increase before finally reaches equilibrium at a particular time. More importantly, the characteristic inversion time τ0 was found to follow a power law increase with the wavelength of incident light (τ0 ∼ λα, where α = 2.07). A quantitative explanation for the wavelength dependence of characteristic time was proposed based on the finite-difference time-domain (FDTD) method. The simulation results are in good agreement with our experimental observations. The time-dependent light scattering in ferrofluids under different incident wavelengths was rationalized by considering both the coarsening process of the particle chains and the occurrence of resonance within the

  6. A Test Facility For Astronomical X-Ray Optics

    DEFF Research Database (Denmark)

    Lewis, R. A.; Bordas, J.; Christensen, Finn Erland


    Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earths atmosphere. These devices require a large collection aperture and the imaging of an x-ray source which is essentially placed at infinity. The ideal testing system for these optical elements has...... to approximate that encountered under working conditions, however the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron Radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area whilst still retaining...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes is described below. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  7. Patient safety incidents are common in primary care: A national prospective active incident reporting survey.

    Directory of Open Access Journals (Sweden)

    Philippe Michel

    Full Text Available The study objectives were to describe the incidence and the nature of patient safety incidents (PSIs in primary care general practice settings, and to explore the association between these incidents and practice or organizational characteristics.GPs, randomly selected from a national influenza surveillance network (n = 800 across France, prospectively reported any incidents observed each day over a one-week period between May and July 2013. An incident was an event or circumstance that could have resulted, or did result, in harm to a patient, which the GP would not wish to recur. Primary outcome was the incidence of PSIs which was determined by counting reports per total number of patient encounters. Reports were categorized using existing taxonomies. The association with practice and organizational characteristics was calculated using a negative binomial regression model.127 GPs (participation rate 79% reported 317 incidents of which 270 were deemed to be a posteriori judged preventable, among 12,348 encounters. 77% had no consequences for the patient. The incidence of reported PSIs was 26 per 1000 patient encounters per week (95% CI [23‰ -28‰]. Incidents were three times more frequently related to the organization of healthcare than to knowledge and skills of health professionals, and especially to the workflow in the GPs' offices and to the communication between providers and with patients. Among GP characteristics, three were related with an increased incidence in the final multivariable model: length of consultation higher than 15 minutes, method of receiving radiological results (by fax compared to paper or email, and being in a multidisciplinary clinic compared with sole practitioners.Patient safety incidents (PSIs occurred in mean once every two days in the sampled GPs and 2% of them were associated with a definite possibility for harm. Studying the association between organizational features of general practices and PSIs remains a

  8. Incident-angle dependency found in track formation sensitivity of a plastic nuclear track detector (TD-1)

    International Nuclear Information System (INIS)

    Yasuda, Hiroshi


    The present study was done since data are hardly available on the incident-angle dependency of track formation sensitivity (S) of the plastic nuclear track detector. Chips of a TD-1 plate, an antioxidant-doped CR-39 (diethyleglycol-bis-allylcarbonate, HARZLAS, Fukuvi Chem. Ind.), were used as a high-LET radiation detector and were exposed to heavy ion beams of C, Ne, and Si under different incident angles in Heavy Ion Medical Accelerator in Chiba of National Institute of Radiological Sciences. After exposed and etched, the chips were observed with an optical microscope and a program for image analysis to calculate S. The S values calculated were found smaller for the beams having lower incident angles. Thus the estimated LET values from the S-LET relationship for vertical incident beams showed large reduction for low-angle particles. Those potential errors should be quantified and corrected in determination of LET spectra in space. (K.H.)

  9. Intelligent Optical Systems Using Adaptive Optics (United States)

    Clark, Natalie


    Until recently, the phrase adaptive optics generally conjured images of large deformable mirrors being integrated into telescopes to compensate for atmospheric turbulence. However, the development of smaller, cheaper devices has sparked interest for other aerospace and commercial applications. Variable focal length lenses, liquid crystal spatial light modulators, tunable filters, phase compensators, polarization compensation, and deformable mirrors are becoming increasingly useful for other imaging applications including guidance navigation and control (GNC), coronagraphs, foveated imaging, situational awareness, autonomous rendezvous and docking, non-mechanical zoom, phase diversity, and enhanced multi-spectral imaging. The active components presented here allow flexibility in the optical design, increasing performance. In addition, the intelligent optical systems presented offer advantages in size and weight and radiation tolerance.

  10. Hazmat Yearly Incident Summary Reports - Data Mining Tool (United States)

    Department of Transportation — Series of Incident data and summary statistics reports produced which provide statistical information on incidents by type, year, geographical location, and others....

  11. Hazmat 10 Year Incident Summary Reports - Data Mining Tool (United States)

    Department of Transportation — Series of Incident data and summary statistics reports produced which provide statistical information on incidents by type, year, geographical location, and others....

  12. Predicting Cumulative Incidence Probability: Marginal and Cause-Specific Modelling

    DEFF Research Database (Denmark)

    Scheike, Thomas H.; Zhang, Mei-Jie


    cumulative incidence probability; cause-specific hazards; subdistribution hazard; binomial modelling......cumulative incidence probability; cause-specific hazards; subdistribution hazard; binomial modelling...

  13. Predicting Cumulative Incidence Probability by Direct Binomial Regression

    DEFF Research Database (Denmark)

    Scheike, Thomas H.; Zhang, Mei-Jie

    Binomial modelling; cumulative incidence probability; cause-specific hazards; subdistribution hazard......Binomial modelling; cumulative incidence probability; cause-specific hazards; subdistribution hazard...

  14. Optical cavity-assisted broadband optical transparency of a plasmonic metal film

    International Nuclear Information System (INIS)

    Liu, Zhengqi; Nie, Yiyou; Yuan, Wen; Liu, Xiaoshan; Huang, Shan; Gao, Huogui; Gu, Gang; Liu, Guiqiang; Chen, Jing


    We theoretically present a powerful method to achieve a continuous metal film structure with broadband optical transparency via introducing a dielectric Fabry–Pérot (FP) cavity. An incident optical field could be efficiently coupled and confined with the strong localized plasmons by the non-close-packed plasmonic crystal at the input part and could then become re-radiated output via the transmission channel supported by the dielectric cavity. The formed photonic-plasmonic system could therefore make the seamless metal film structure have a superior near-unity transparency (up to 97%) response and a broadband transparent spectrum with bandwidth >245 nm (with transmittance >90%) in the optical regime. The observed optical properties of the proposed structure can be highly tuned via varying the structural parameters. Based on the colloidal assembly method, the proposed plasmonic crystal can be fabricated in a large area. In addition, the achieved optical transparency can be retained in the extremely roughed metal film structure. Thereby, the findings could offer a feasible way to achieve a broadband transparent metal film structure and hold potential applications in transparent electrodes, touch screens and interactive electronics. (paper)

  15. Incidence of pancreatic cancer in Denmark

    DEFF Research Database (Denmark)

    Weble, Tanja Cruusberg; Bjerregaard, Jon Kroll; Kissmeyer, Peter


    standardization. We used absolute numbers from the Cancer Registry and the Pancreatic Cancer Database, including distribution of topography of cancers registered in 2012-2013, to compare registration in the two data sources. RESULTS: The incidence rates of pancreatic cancer among Danish men increased until 1968......BACKGROUND: The aim of this study was to monitor the evolution of the incidence of pancreatic cancer in Denmark over 70 years. We also compared registrations of pancreatic cancer in a nationwide population-based database, the Danish Cancer Registry, and a clinical database, the Danish Pancreatic...... Cancer Database, in 2012-2013. MATERIAL AND METHODS: Registrations of pancreatic cancer from the Danish Cancer Registry over 1943-2012 were used to calculate age-specific incidence rates per 100 000 person years by sex and age in 5-year period, weighted by the Segi World Standard Population for age...

  16. Statement of nuclear incidents at nuclear installations

    International Nuclear Information System (INIS)


    Three incidents were reported in April-June 1993. The first was on the British Nuclear Fuel plc (BNFL) site at Sellafield and concerned leakage of 0.5 TBq of alpha activity from plutonium contaminated waste stored in a steel drum. This was subsequently double contained and moved so it could be inspected regularly. No contamination of personnel occurred. The second concerned the leakage of thorium liquor from a pipe at the UKAEA's Thorium reprocessing plant at Dounreay. Two temporary repairs were made and no personnel were contaminated. The third was at the Sellafield site where a small quantity (5 mls) of plutonium containing liquor had leaked from a package and released alpha activity. The bags were temporary containment of engineering debris which may have had sharp edges. The bags had been piled up and one of the bags had torn. Recommendations were made following inquiries into each of the incidents to improve procedures and prevent similar incidents occurring. (UK)

  17. Hepatitis B prevalence and incidence in Greenland

    DEFF Research Database (Denmark)

    Børresen, Malene Landbo; Andersson, Mikael; Wohlfahrt, Jan


    Greenland remains a highly endemic area for hepatitis B virus (HBV) infection. This is in sharp contrast to other modern societies, such as Denmark. To address this discrepancy, we investigated the natural history of HBV infection in Greenland by estimating the age-specific incidence of HBV...... infection, the proportion of chronic carriers, and the rates of hepatitis B surface antigen seroclearance. In total, 8,879 Greenlanders (16% of the population) from population-based surveys conducted in 1987 and 1998 were followed through March 2010. Data on HBV status were supplemented by HBV test results...... from all available HBV registries in Greenland to determine changes in HBV status over time. Incidence rates of HBV infection and hepatitis B surface antigen seroclearance were estimated after taking into account interval censoring. The incidence of HBV infection in 5-14-year-old subjects was less than...

  18. Cardiorespiratory fitness, fatness and incident diabetes

    DEFF Research Database (Denmark)

    Holtermann, Andreas; Gyntelberg, Finn; Bauman, Adrian


    with diabetes incidence were estimated in multivariable Cox-models including conventional risk factors and social class. Diabetes incidence was assessed through a national register. Results During 44 years of follow-up, 518 (10.4%) incident cases of diabetes occurred. In the multi-adjusted model, the obese had......: 0.76–1.23). Conclusion High CRF has a stronger protective effect on diabetes among obese than among normal weight men, supporting the recommendation of fitness-enhancing physical activity for preventing diabetes among the obese.......Aims Increases in prevalence have led to a diabetes pandemic. Obesity and low cardiorespiratory fitness (CRF) are considered to be central mechanisms. We investigated if the effect of CRF on diabetes risk was equivalent across levels of fatness among healthy men. Methods In total 4988 middle...

  19. Incidence and prevalence of epilepsy in Denmark

    DEFF Research Database (Denmark)

    Christensen, Jakob; Vestergaard, Mogens; Pedersen, Marianne G


    PURPOSE: To estimate the occurrence of epilepsy in Denmark between 1977 and 2002, taking gender, age, and secular trends into consideration. METHODS: We used the Danish Civil Registration System to identify all persons born in Denmark and the Danish National Hospital Register to identify persons...... registered with epilepsy between 1977 and 2002. RESULTS: Between 1977 and 2002 the average incidence of epilepsy was 68.8 new epilepsy patients per 100,000 person-years at risk. However, the incidence changed with calendar time and increased steeply from 1990 to 1995, probably due to changes in diagnostic...... declined from a high level in children to a low level between 20 and 40 years of age, and thereafter a gradual increase was seen. The incidence rate was slightly higher in men than in women except for the age range 10-20 years. About 2% of the population was diagnosed with epilepsy at some point during...

  20. Self-sifting of chain plasmons: the complex optics of Au nanoparticle clusters. (United States)

    Herrmann, L O; Valev, V K; Aizpurua, J; Baumberg, J J


    The strong enhancement of electrical fields in subnanometer gaps of self-assembled gold nanoparticle clusters holds great promise for large scale fabrication of sensitive optical sensing substrates. Due to the large number of involved nanoparticles, however, their optical response is complex and not easily accessible through numerical simulations. Here, we use hyperspectral supercontinuum spectroscopy to demonstrate how confined optical modes of well defined energies are supported by different areas of the cluster. Due to the strong resonant coupling in those regions, the cluster essentially acts as a nanoscale optical sieve which sorts incident light according to its wavelength.

  1. Incidence of eating disorders in Navarra (Spain). (United States)

    Lahortiga-Ramos, Francisca; De Irala-Estévez, Jokin; Cano-Prous, Adrián; Gual-García, Pilar; Martínez-González, Miguel Angel; Cervera-Enguix, Salvador


    To estimate the overall annual incidence and age group distribution of eating disorders in a representative sample of adolescent female residents of Navarra, Spain. We studied a representative sample of 2734 adolescent Navarran females between 13 and 22 years of age who were free of any eating disorder at the start of our study. Eighteen months into the study, we visited the established centers and the eating attitudes test (EAT-40) and eating disorder inventory (EDI) Questionnaires were administered to the entire study population. We obtained a final response of 92%. All adolescents whose EAT score was over 21 points and a randomized sample of those who scored 21 or below, were interviewed. Any person meeting the DSM-IV diagnostic criteria for Anorexia Nervosa (AN), Bulimia Nervosa (BN) or eating disorder not otherwise specified (EDNOS) was considered a case. We detected 90 new cases of eating disorders. Taking into consideration the randomly selected group whose EAT score was 21 points or below, we estimated the overall weighted incidence of eating disorders to be 4.8% (95% CI: 2.8-6.8), after 18 months of observation, in which EDNOS predominated with an incidence of 4.2% (95% CI: 2.0-6.3). The incidence of AN was 0.3% (95% CI: 0.2-0.5), while that of BN was also found to be 0.3% (95% CI: 0.2-0.5). The highest incidence was observed in the group of adolescents between 15 and 16 years of age. The overall incidence of ED in a cohort of 2509 adolescents after 18 months of follow-up was 4.8% (95% CI: 2.8-6.8), with EDNOS outweighing the other diagnoses. The majority of new cases of eating disorders were diagnosed between ages 15 and 16.

  2. Incidence and characteristics of chemical burns. (United States)

    Koh, Dong-Hee; Lee, Sang-Gil; Kim, Hwan-Cheol


    Chemical burns can lead to serious health outcomes. Previous studies about chemical burns have been performed based on burn center data so these studies have provided limited information about the incidence of chemical burns at the national level. The aim of this study was to evaluate the incidence and characteristics of chemical burns using nationwide databases. A cohort representing the Korean population, which was established using a national health insurance database, and a nationwide workers' compensation database were used to evaluate the incidence and characteristics of chemical burns. Characteristics of the affected body region, depth of burns, industry, task, and causative agents were analyzed from two databases. The incidence of chemical burns was calculated according to employment status. The most common regions involving chemical burns with hospital visits were the skin followed by the eyes. For skin lesions, the hands and wrists were the most commonly affected regions. Second degree burns were the most common in terms of depth of skin lesions. The hospital visit incidence was 1.96 per 10,000 person-year in the general population. The compensated chemical burns incidence was 0.17 per 10,000 person-year. Employees and the self-employed showed a significantly increased risk of chemical burns undergoing hospital visits compared to their dependents. Chemical burns on the skin and eyes are almost equally prevalent. The working environment was associated with increased risk of chemical burns. Our results may aid in estimating the size of the problem and prioritizing prevention of chemical burns. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

  3. Cancer incidence among Nordic airline cabin crew. (United States)

    Pukkala, Eero; Helminen, Mika; Haldorsen, Tor; Hammar, Niklas; Kojo, Katja; Linnersjö, Anette; Rafnsson, Vilhjálmur; Tulinius, Hrafn; Tveten, Ulf; Auvinen, Anssi


    Airline cabin crew are occupationally exposed to cosmic radiation and jet lag with potential disruption of circadian rhythms. This study assesses the influence of work-related factors in cancer incidence of cabin crew members. A cohort of 8,507 female and 1,559 male airline cabin attendants from Finland, Iceland, Norway and Sweden was followed for cancer incidence for a mean follow-up time of 23.6 years through the national cancer registries. Standardized incidence ratios (SIRs) were defined as ratios of observed and expected numbers of cases. A case-control study nested in the cohort (excluding Norway) was conducted to assess the relation between the estimated cumulative cosmic radiation dose and cumulative number of flights crossing six time zones (indicator of circadian disruption) and cancer risk. Analysis of breast cancer was adjusted for parity and age at first live birth. Among female cabin crew, a significantly increased incidence was observed for breast cancer [SIR 1.50, 95% confidence interval (95% CI) 1.32-1.69], leukemia (1.89, 95% CI 1.03-3.17) and skin melanoma (1.85, 95% CI 1.41-2.38). Among men, significant excesses in skin melanoma (3.00, 95% CI 1.78-4.74), nonmelanoma skin cancer (2.47, 95% CI 1.18-4.53), Kaposi sarcoma (86.0, 95% CI 41.2-158) and alcohol-related cancers (combined SIR 3.12, 95% CI 1.95-4.72) were found. This large study with complete follow-up and comprehensive cancer incidence data shows an increased incidence of several cancers, but according to the case-control analysis, excesses appear not to be related to the cosmic radiation or circadian disruptions from crossing multiple time zones. Copyright © 2012 UICC.

  4. Traffic incidents in motorways : An empirical proposal for incident detection using data from mobile phone operators

    NARCIS (Netherlands)

    Steenbruggen, John; Tranos, Emmanouil; Rietveld, P.


    This paper proves that mobile phone usage data is an easy to use, cheap and most importantly, reliable predictor of motorway incidents. Using econometric modelling, this paper provides a proof of concept of how mobile phone usage data can be utilised to detect motorway incidents. Greater Amsterdam

  5. The Role of Technology in Medication Safety Incidents: Interpretative Analysis of Patient Safety Incidents Data. (United States)

    Lichtner, Valentina; Gerrett, David; Slee, Ann; Gul, Noreen; Cornford, Tony


    This is a study of medication safety incidents reported to the NHS in England (UK) associated with the use of digital technology. An interpretative analysis of 888 incidents reports offers insight into uses and features of this technology associated with medication errors and potential patient harm.

  6. The Role of Technology in Medication Safety Incidents: Interpretative Analysis of Patient Safety Incidents Data


    Lichtner, V.; Gerrett, D.; Slee, A.; Gul, N.; Cornford, T.


    This is a study of medication safety incidents reported to the NHS in England (UK) associated with the use of digital technology. An interpretative analysis of 888 incidents reports offers insight into uses and features of this technology associated with medication errors and potential patient harm.

  7. Incidence and latency of radiation reactions

    International Nuclear Information System (INIS)

    Bentzen, S.M.; Thames, H.D.


    Like any other pathological condition, radiation reactions are characterized not only by their incidence (i.e. frequency) but also buy their latent period. The difference between latencies is the basis for the biologically and clinically important distinction between early and late radiation reactions. The authors conclude in this letter that a hazard-rate type of analysis does not allow separation of the effects of incidency and latency. The authors feel that a more adequate framework for analysis of latent-time distributions is provided bu the mixture model. Currenctly, the hydronephrosis data by Knowles and Trott are being reanalyzed using the model. (author). 8 refs.; 1 fig

  8. Rising incidence of Merkel cell carcinoma

    DEFF Research Database (Denmark)

    Lyhne, Dorte; Lock-Andersen, Jørgen; Dahlstrøm, Karin


    Abstract Merkel cell carcinoma (MCC) is a rare, aggressive, skin cancer of obscure histogenesis, the incidence of which is rising. There is no consensus on the optimal treatment. Our aim was to evaluate the staging, investigation, treatment, and follow-up of MCC in eastern Denmark, and to investi......Abstract Merkel cell carcinoma (MCC) is a rare, aggressive, skin cancer of obscure histogenesis, the incidence of which is rising. There is no consensus on the optimal treatment. Our aim was to evaluate the staging, investigation, treatment, and follow-up of MCC in eastern Denmark...

  9. Incidence, etiology and mortality of cirrhosis

    DEFF Research Database (Denmark)

    Dam Fialla, Annette; Schaffalitzky de Muckadell, Ove B; Touborg Lassen, Annmarie


    Knowledge on the prognosis among patients with cirrhosis is mainly based on clinical trials with selected patient groups as well as population-based register studies with suboptimal diagnostic reliability. The aim of the study was to describe incidence, etiology, and mortality of well-validated c......Knowledge on the prognosis among patients with cirrhosis is mainly based on clinical trials with selected patient groups as well as population-based register studies with suboptimal diagnostic reliability. The aim of the study was to describe incidence, etiology, and mortality of well...

  10. Incident Command System - Environmental Unit responsibilities

    International Nuclear Information System (INIS)

    Hillman, S. O.


    The Incident Command System (ICS) for crisis management, used for response to oil spills by the Alyeska Pipeline Service Company throughout its facilities, including the Trans Alaska Pipeline and the Valdez Marine Terminal, was described. Special attention was given to the Environmental Unit within the ICS which functions as a primary support unit for the Incident Operations Section. Details of the Unit's function were provided. These include the collection, evaluation and dissemination of information on all environmental issues concerning the crisis, provision of advice and direction on environmental aspects, and up-front agency interaction. A checklist of tasks is included. 7 refs

  11. Incidence of blindness in southern Germany due to glaucoma and degenerative conditions. (United States)

    Trautner, Christoph; Haastert, Burkhard; Richter, Bernd; Berger, Michael; Giani, Guido


    To estimate population-based incidence rates of registered blindness separately, to determine its main causes. The files of all newly registered blindness-allowance recipients in Württemberg-Hohenzollern, Germany (population: approximately 5 million), between 1994 and 1998 were reviewed. From ophthalmological reports on file the fulfillment of the German criteria for blindness (visual acuity of 1/50 or less or equivalent reduction of visual function) was ascertained, and the causes of blindness were obtained. Incidence rates of blindness due to macular degeneration, glaucoma, cataract, optic atrophy, and diabetic retinopathy were estimated. There were 3531 newly registered blindness-allowance recipients (67.1% female; mean age, 72.8 +/- 21.0 years). Standardized incidence rates in the general population (per 100,000 person-years; 95% confidence interval): All causes 12.27 (11.87-12.68), macular degeneration 5.29 (5.02-5.55), cataract 3.32 (3.11-3.52), optic atrophy 2.86 (2.66-3.05), glaucoma 2.43 (2.25-2.61), diabetic retinopathy 2.13 (1.96-2.30), other or unknown causes 5.17 (4.91-5.43). In many cases, blindness was attributable to more than one cause. Assuming that incidence rates are the same in other parts of the country, 9,939 (9,608-10,270) new cases of blindness were estimated to occur in Germany per year. The most common single cause of blindness was macular degeneration. Incidence rates of blindness due to such treatable conditions as glaucoma were also high. This finding suggests that the taking of measures for secondary prevention (e.g., early detection and optimal treatment of patients with glaucoma and diabetic retinopathy) should be intensified.

  12. Multimode optical fiber (United States)

    Bigot-Astruc, Marianne; Molin, Denis; Sillard, Pierre


    A depressed graded-index multimode optical fiber includes a central core, an inner depressed cladding, a depressed trench, an outer depressed cladding, and an outer cladding. The central core has an alpha-index profile. The depressed claddings limit the impact of leaky modes on optical-fiber performance characteristics (e.g., bandwidth, core size, and/or numerical aperture).

  13. Touch screens go optical

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner; Jakobsen, Michael Linde; Pedersen, Henrik Chresten


    A simple optical implementation of a touch screen is made possible by disrupting the total internal reflection in a 2D waveguide.......A simple optical implementation of a touch screen is made possible by disrupting the total internal reflection in a 2D waveguide....

  14. Torque and optical traps

    African Journals Online (AJOL)



    Dec 29, 2008 ... Optical traps are an important tool for research in the field of single molecule biophysics. Recent advances in optical trapping have extended their functionality from simple linear manipulation and measurement of forces, to now the ability to rotate objects and measure torques. This mini review summarizes ...

  15. Genetically determined optic neuropathies

    DEFF Research Database (Denmark)

    Milea, Dan; Amati-Bonneau, Patrizia; Reynier, Pascal


    The present review focuses on recent advances in the knowledge of hereditary optic neuropathies resulting from retinal ganglion cell degeneration, mostly due to mitochondrial dysfunctions.......The present review focuses on recent advances in the knowledge of hereditary optic neuropathies resulting from retinal ganglion cell degeneration, mostly due to mitochondrial dysfunctions....

  16. Isolated optic nerve pseudotumour

    International Nuclear Information System (INIS)

    Patankar, T.; Prasad, S.; Krishnan, A.; Laxminarayan, R.


    Isolated optic nerve involvement by the idiopathic inflammatory process is a rare finding and very few reports are available. Here a case of an isolated optic nerve inflammatory pseudotumour presenting with gradually progressive unilateral loss of vision is described. It showed dramatic response to a trial of steroids and its differential diagnoses are discussed. Copyright (1999) Blackwell Science Pty Ltd

  17. Electromagnetics and optics

    National Research Council Canada - National Science Library

    Kriezis, E. E; Chrissoulidis, D. P; Papagiannakis, A. G


    ..., since light is a high-frequency electromagnetic radiation. Although both electromagnetics and optics are their common origin is only superficially realised physics or electrical engineering. Deeper physical by treating electromagnetics and optics in parallel thus enlightening the natural link between them. By presenting principles, theory a...

  18. Stochastic singular optics

    CSIR Research Space (South Africa)

    Roux, FS


    Full Text Available Roux Presented at the International Conference on Correlation Optics 2013 Chernivtsi, Ukraine 18-20 September 2013 CSIR National Laser Centre, Pretoria, South Africa – p. 1/24 Contents ⊲ Defining Stochastic Singular Optics (SSO) ⊲ Tools of Stochastic...

  19. Stitching in optical processors (United States)

    Caulfield, H. John


    Optical processing is supposed to be advantageous in very big problems, because it can handle those problems with minimal spatial and temporal complexity. What happens, though at the other extreme, where the problem is too big to be input into the optical system? I offer some preliminary thoughts here.

  20. Incident diabetes mellitus may explain the association between sleep duration and incident coronary heart disease. (United States)

    Svensson, Akiko Kishi; Svensson, Thomas; Kitlinski, Mariusz; Almgren, Peter; Engström, Gunnar; Nilsson, Peter M; Melander, Olle


    Sleep duration is a risk factor for incident diabetes mellitus and CHD. The primary aim of the present study was to investigate, in sex-specific analyses, the role of incident diabetes as the possible biological mechanism for the reported association between short/long sleep duration and incident CHD. Considering that diabetes is a major risk factor for CHD, we hypothesised that any association with sleep duration would not hold for cases of incident CHD occurring before incident diabetes ('non-diabetes CHD') but would hold true for cases of incident CHD following incident diabetes ('diabetes-CHD'). A total of 6966 men and 9378 women aged 45-73 years from the Malmö Diet Cancer Study, a population-based, prospective cohort, who had answered questions on habitual sleep duration and did not have a history of prevalent diabetes or CHD were included in the analyses. Incident cases of diabetes and CHD were identified using national registers. Sex-specific Cox proportional hazards regression models were stratified by BMI and adjusted for known covariates of diabetes and CHD. Mean follow-up times for incident diabetes (n = 1137/1016 [men/women]), incident CHD (n = 1170/578), non-diabetes CHD (n = 1016/501) and diabetes-CHD (n = 154/77) were 14.2-15.2 years for men, and 15.8-16.5 years for women. In men, short sleep duration (< 6 h) was associated with incident diabetes (HR 1.35, 95% CI 1.01, 1.80), CHD (HR 1.41, 95% CI 1.06, 1.89) and diabetes-CHD (HR 2.34, 95% CI 1.20, 4.55). Short sleep duration was not associated with incident non-diabetes CHD (HR 1.35, 95% CI 0.98, 1.87). Long sleep duration (≥ 9 h) was associated with incident diabetes (HR 1.37, 95% CI 1.03, 1.83), CHD (HR 1.33, 95% CI 1.01, 1.75) and diabetes-CHD (HR 2.10, 95% CI 1.11, 4.00). Long sleep duration was not associated with incident non-diabetes CHD (HR 1.33, 95% CI 0.98, 1.80). In women, short sleep duration was associated with incident diabetes (HR 1.53, 95% CI 1.16, 2.01), CHD (HR 1

  1. Elements of quantum optics

    CERN Document Server

    Meystre, Pierre


    Elements of Quantum Optics gives a self-contained and broad coverage of the basic elements necessary to understand and carry out research in laser physics and quantum optics, including a review of basic quantum mechanics and pedagogical introductions to system-reservoir interactions and to second quantization. The text reveals the close connection between many seemingly unrelated topics, such as probe absorption, four-wave mixing, optical instabilities, resonance fluorescence and squeezing. It also comprises discussions of cavity quantum electrodynamics and atom optics. The 4th edition includes a new chapter on quantum entanglement and quantum information, as well as added discussions of the quantum beam splitter, electromagnetically induced transparency, slow light, and the input-output formalism needed to understand many problems in quantum optics. It also provides an expanded treatment of the minimum-coupling Hamiltonian and a simple derivation of the Gross-Pitaevskii equation, an important gateway to rese...

  2. Optically Anomalous Crystals

    CERN Document Server

    Shtukenberg, Alexander; Kahr, Bart


    Optical anomalies in crystals are puzzles that collectively constituted the greatest unsolved problems in crystallography in the 19th Century. The most common anomaly is a discrepancy between a crystal’s symmetry as determined by its shape or by X-ray analysis, and that determined by monitoring the polarization state of traversing light. These discrepancies were perceived as a great impediment to the development of the sciences of crystals on the basis of Curie’s Symmetry Principle, the grand organizing idea in the physical sciences to emerge in the latter half of the 19th Century. Optically Anomalous Crystals begins with an historical introduction covering the contributions of Brewster, Biot, Mallard, Brauns, Tamman, and many other distinguished crystallographers. From this follows a tutorial in crystal optics. Further chapters discuss the two main mechanisms of optical dissymmetry: 1. the piezo-optic effect, and 2. the kinetic ordering of atoms. The text then tackles complex, inhomogeneous crystals, and...

  3. Introduction to Optics

    CERN Document Server

    Chartier, Germain


    Since the discovery of the laser in 1960 and optical fibers in 1970, optics has undergone dramatic changes that accentuate its multi-disciplinary character. This text covers essential concepts and reports the key developments and progress in current knowledge in the field. Inspired by the style of Richard Feynman, the method of presentation emphasizes "telling" optics, rather than deducing it from fundamental laws, as well as tactfully using mathematical tools so as not to obscure the physical phenomena of interest. For its excellent teaching approach, the book received the Arnulf-Francon Award of the French Optical Society. The concepts are formulated in a way such that the necessary mathematical tools do not hinder comprehension of the phenomena. Global in vision, the book can also be used as a reference. In addition to the traditional aspects of optics, it includes the tools and methods currently used by researchers and engineers, as well as explanation and implications of the most recent developments.

  4. Nonlinear optics and photonics

    CERN Document Server

    He, Guang S


    This book provides a comprehensive presentation on most of the major topics in nonlinear optics and photonics, with equal emphasis on principles, experiments, techniques, and applications. It covers many major new topics including optical solitons, multi-photon effects, nonlinear photoelectric effects, fast and slow light , and Terahertz photonics. Chapters 1-10 present the fundamentals of modern nonlinear optics, and could be used as a textbook with problems provided at the end of each chapter. Chapters 11-17 cover the more advanced topics of techniques and applications of nonlinear optics and photonics, serving as a highly informative reference for researchers and experts working in related areas. There are also 16 pages of color photographs to illustrate the visual appearances of some typical nonlinear optical effects and phenomena. The book could be adopted as a textbook for both undergraduates and graduate students, and serve as a useful reference work for researchers and experts in the fields of physics...

  5. The Optics of Bruising (United States)

    Randeberg, Lise Lyngsnes; Skallerud, Bjørn; Langlois, Neil E. I.; Haugen, Olav Anton; Svaasand, Lars Othar

    Forensic medicine is a field of medicine where technology plays an increasingly important role in securing and evaluating evidence in, for example, child abuse cases and cases of domestic violence. Methods from chemistry and biological sciences have found a wide application within forensic medicine. Optical technologies like microscopy are also widely used. Despite this, in vivo or post mortem optical diagnostics by spectroscopy have traditionally not had an important role in clinical or forensic examinations. Forensic medical optics as a field might include all kinds of optical analysis for use within forensic science. This includes everything from microscopic techniques to methods for examination of evidence from a crime scene. This chapter will, however, focus on the use of optical diagnostics for examining skin, with a focus on identification, characterization and age determination of minor traumatic injuries like skin bruises.

  6. Optical analogy. Synthesis report

    International Nuclear Information System (INIS)


    The authors report the study of conditions under which light attenuation (reflection, diffusion, absorption) and the attenuation of some radiations (notably thermal neutrons) can be described with analogical calculations. The analogy between light physical properties and neutron properties is not searched for, but the analogy between their attenuation characteristics. After having discussed this possible analogy, they propose a mathematical formulation of neutron and optical phenomena which could theoretically justify the optical analogy. The second part reports a more practical study of optics problems such as the study of simple optics materials and illumination measurements, or more precisely the study of angular distributions of optical reflections, a determination of such angular distributions, and an experimental determination of the albedo

  7. Fiber optics standard dictionary

    CERN Document Server

    Weik, Martin H


    Fiber Optics Vocabulary Development In 1979, the National Communications System published Technical InfonnationBulle­ tin TB 79-1, Vocabulary for Fiber Optics and Lightwave Communications, written by this author. Based on a draft prepared by this author, the National Communications System published Federal Standard FED-STD-1037, Glossary of Telecommunications Terms, in 1980 with no fiber optics tenns. In 1981, the first edition of this dictionary was published under the title Fiber Optics and Lightwave Communications Standard Dictionary. In 1982, the then National Bureau of Standards, now the National Institute of Standards and Technology, published NBS Handbook 140, Optical Waveguide Communications Glossary, which was also published by the General Services Admin­ istration as PB82-166257 under the same title. Also in 1982, Dynamic Systems, Inc. , Fiberoptic Sensor Technology Handbook, co-authored and edited by published the this author, with an extensive Fiberoptic Sensors Glossary. In 1989, the handbook w...

  8. Optical computer switching network (United States)

    Clymer, B.; Collins, S. A., Jr.


    The design for an optical switching system for minicomputers that uses an optical spatial light modulator such as a Hughes liquid crystal light valve is presented. The switching system is designed to connect 80 minicomputers coupled to the switching system by optical fibers. The system has two major parts: the connection system that connects the data lines by which the computers communicate via a two-dimensional optical matrix array and the control system that controls which computers are connected. The basic system, the matrix-based connecting system, and some of the optical components to be used are described. Finally, the details of the control system are given and illustrated with a discussion of timing.

  9. Two to the sixth and counting: a lifetime of optical experiences (United States)

    Mayo, Jim


    This presentation will cover 64 years of experience with telescopes, optical components, optical coatings, large optics, optical fabrication, lasers and related subjects. It will focus on five topic areas paying special attention to critical lessons learned in these areas. Part 1 will cover contributions and inherent value of mentoring in optical and astronomical sciences. This will include specific personal experiences and valuable lessons learned from teachers and mentors going back to the beginning of the space age and the first satellites. It will also cover selected examples from the author's mentoring and community optics and astronomy outreach efforts. Part 2 will delineate the lessons learned from the investigation and independent expert review and assessment of optical damage incidents over a period of five decades. It will also recount frequent optical misconceptions that have negatively impacted efficient system development and implementation over the years and how to avoid them. Part 3 will consist of a short tutorial on the tools, techniques, and the "how and why" of optical inspection. This will be interlinked with the previous optical damage and mistakes topic, where possible. Part 4 will consist of the author's involvement and experiences in optical education with emphasis on the founding and early years of the University of Arizona Optical Sciences Center, now the College of Optical Sciences. Part 5 will cover the enduring issues and challenges for managers, planners and contributing scientists for large optics and telescope projects. This brief overview will follow up and expand upon the author's presentation on this topic at the 1985 "SPIE Optical Fabrication and Testing Workshop: Large Telescope Optics", Albuquerque, NM. Throughout all topic areas presented, the author will stress the lessons learned and the value of these lessons to the planning, management and successful execution of future optics projects and programs.

  10. Structural, optical spectroscopy, optical conductivity, dielectric ...

    Indian Academy of Sciences (India)


    different methods of preparation [36-41]. The electrical insulator materials with low refractive index and low absorption are needed for various optical devices, such as low loss waveguides, resonators, photonic crystals, distributed Bragg reflectors, light-emitting diodes, passive splitters, biosensors, attenuators and filters ...

  11. Integrated-optics-based optical coherence tomography

    NARCIS (Netherlands)

    Nguyen, D.V.


    Optical coherence tomography (OCT) is a high resolution, imaging technique that has developed over the last 20 years from a complicated laboratory setup into a ready-to-use commercially available device. Instead of using electronic time gating as being used by ultrasound (US) imaging, in OCT, the

  12. Optics equations for aero-optical analysis (United States)

    Sutton, George W.; Pond, John E.


    Aero-optical effects occur around moving air vehicles and impact passive imaging or active systems. The air flow around the vehicle is compressed, and often there is a turbulent shear and/or boundary layer both of which cause variations in the index of refraction. Examples of these are reconnaissance aircraft, the Stratospheric Observatory for Infrared Optics (SOFIA), and optically homing hypersonic interceptors. In other applications, a laser beam can be formed within the vehicle, and projected outward and focused on an object. These include the Airborne Laser Laboratory, Airborne Laser and the Airborne Tactical Laser. There are many compressible fluid mechanics computer programs that can predict the air density distribution of the surrounding flow field including density fluctuations in turbulent shear and/or boundary layers. It is necessary for the physical optics to be used to predict the properties of the ensuing image plane intensity distribution, whether passive or active. These include the time-averaged image blur circle and instantaneous realizations. (Ray tracing is a poor approximation that gives erroneous results for small aberrations.)

  13. Miniature Optical Isolator, Phase II (United States)

    National Aeronautics and Space Administration — To address NASA's need for compact optical isolators, Physical Optics Corporation (POC) proposes to continue the development of a new Miniature Optical Isolator...

  14. Three Dimensionally Interconnected Silicon Nanomembranes for Optical Phased Array (OPA) and Optical True Time Delay (TTD) Applications (United States)


    spectroscopy of xylene in water," Appl. Phys. Lett. 98 (2), 023304 (2011). [8-22] Xiaonan Chen, Wei Jiang, Jiaqi Chen, Lanlan Gu, and Ray T. Chen...representative arrays of silicon pi structures. 13.3 Optical characterization of Si-based FRAMMs using FTIR (normal incidence) Transmission at normal...incidence was obtained using house-built angle-resolved FTIR setup. For the L12 sample (short antenna is 1.2 μm long), the normal transmission spectrum is

  15. The incidence of anorexia nervosa on Curacao

    NARCIS (Netherlands)

    Hoek, HW; van Harten, PN; Hermans, KME; Katzman, MA; Matroos, GE; Susser, ES

    Objective: Although anorexia nervosa was once thought to occur only in affluent societies, cases have now been documented across the globe. To examine whether anorexia nervosa emerges in societies undergoing socioeconomic transition, the authors studied the incidence of anorexia nervosa on the

  16. National Toxic Substance Incidents Program (NTSIP)

    Centers for Disease Control (CDC) Podcasts


    This podcast gives an overview of the three components of the National Toxic Substance Incidents Program: state surveillance, national database, and response teams.  Created: 2/3/2011 by Agency for Toxic Substances and Disease Registry.   Date Released: 2/3/2011.

  17. Grazing incidence polarized neutron scattering in reflection ...

    Indian Academy of Sciences (India)

    During the year 1980, polarized neutron scattering technique came into being as an ana- lytic tool to measure the ... The discovery of antiferromagnetic coupling was critical to the discovery of GMR, pro- viding as it did ..... Here we consider the incident wave vector ki making an angle αi in the x–z plane while the scattered ...

  18. Perceptions and Incidence of Test Anxiety (United States)

    Gerwing, Travis G.; Rash, Joshua A.; Allen Gerwing, Alyssa M.; Bramble, Bev; Landine, Jeff


    Test anxiety (TA) can lower student GPA and increase dropout rates in populations of university students. Despite numerous treatment options, many students still suffer from TA. The stigma attached to this type of anxiety and the incidence rates and perceptions of TA were quantified through surveys distributed to 1,099 students at a Canadian…

  19. Low-Incidence, High-Consequence Pathogens

    Centers for Disease Control (CDC) Podcasts


    Dr. Stephan Monroe, a deputy director at CDC, discusses the impact of low-incidence, high-consequence pathogens globally.  Created: 2/21/2014 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/26/2014.

  20. Preparing for major incidents in Kenya

    Directory of Open Access Journals (Sweden)

    B.W. Wachira*


    This report provides a review of some of the major incidents in Kenya for the period 2000–2012, with the hope of highlighting the importance of developing an integrated and well-trained Ambulance and Fire and Rescue service appropriate for the local health care system.

  1. Pipework failures - a review of historical incidents

    International Nuclear Information System (INIS)

    Blything, K.W.; Parry, S.T.


    A description is presented of the gathering of historical pipework incident data and its analysis to determine the causes and underlying reasons for failure. The following terms of reference were agreed: (a) To review data on failures associated with pipework to establish the principal causes of failure. This should include not only rupture of the pipe itself, but also pipework induced failures, such as severe flange leaks and excessive strains resulting in failure of connected equipment. (b) To suggest an incident classification for pipework systems which will alert design, construction, maintenance, and operating personnel to the need for special care. (c) To advise non-piping specialists of the type of situation which could result in failure if not allowed for in the design, e.g. dynamic and transient conditions. (d) To recommend, possibly as the result of (a) above, areas where present procedures and codes of practice may require amplification. Brief descriptions are given of selected incidents where the consequences are considered to be serious in terms of damage and financial loss. For consequence analysis, the release rate is an important parameter and, where possible, the proportion of incidents in the failure mode categories, leaks, ''ruptures/severances'' are given. Although not one of the agreed objectives, the determination of failure rates was recognised as an important requirement in the risk assessment of pipework systems. The quality of data gathered however was found to be inadequate for any statistical analysis and no failure rate values are given in this report. (author)

  2. Urbanisation and the incidence of eating disorders

    NARCIS (Netherlands)

    Van Son, Gabrielle E.; Van Hoeken, Daphne; Bartelds, Aad I. M.; Van Furth, Eric F.; Hoek, Hans W.


    The link between degree of urbanisation and a number of mental disorders is well established. Schizophrenia, psychosis and depression are known to occur more frequently in urban areas. In our primary care-based study of eating disorders, the incidence of bulimia nervosa showed a dose-response

  3. Unmodifiable variables related to thyroid cancer incidence

    Directory of Open Access Journals (Sweden)

    Cornelia Nitipir


    Full Text Available The incidence of thyroid cancer is significantly different between male and female patients. Thyroid cancer is also the only form of cancer where age can be considered a staging variable. Identifying biological prognostic factors such as age or sex is important as it helps select an optimal personalized therapy. The present analysis is an observational, prospective study that enrolled all patients with thyroid disease who were operated upon at a single center. The study aimed to determine the most frequent age at presentation, the predominance of one sex over the other, the incidence of malignant thyroid disease, and the relative risk for each sex to develop thyroid carcinoma. The incidence of thyroid carcinoma was higher for women than for men, with a higher relative risk in the female subgroup. Incidence was also highest in the 50-60-year-old group. Given that studies show better survival for women and for younger patients, even when presenting with advanced disease, compared with older, male patients, such prognostic indicators should be a factor in the treatment decision.

  4. Representative Incidents in the Adoption Process. (United States)

    Farrington, Jay A.; And Others

    This paper presents three case studies of innovation, based on interviews with six adoption agents. Key episodes and incidents which illustrate important principles are drawn from the experiences of these adoption agents. The case studies offer examples of both success and failure--by both internal and external adoption agents. They also emphasize…

  5. Incident Management Organization succession planning stakeholder feedback (United States)

    Anne E. Black


    This report presents complete results of a 2011 stakeholder feedback effort conducted for the National Wildfire Coordination Group (NWCG) Executive Board concerning how best to organize and manage national wildland fire Incident Management Teams in the future to meet the needs of the public, agencies, fire service and Team members. Feedback was collected from 858...

  6. Cervical cancer incidence in elderly women

    DEFF Research Database (Denmark)

    Lynge, Elsebeth; Lönnberg, Stefan; Törnberg, Sven


    was to determine whether this bipolar pattern in age-specific incidence of cervical cancer reflects underlying biology or can be explained by the fact that the data come from birth cohorts with different screening histories. Methods: Combination of historical data on cervical screening and population-based cancer...

  7. Review: Childhood and Adolescent Sexual Abuse: Incidence ...

    African Journals Online (AJOL)

    Other complications relate to sexually transmitted diseases, unwanted pregnancy and psychological pathologies such as intense anxiety, anger, depression, mood swings, nightmares, phobias and somatisation. This review discusses the apparent low incidence and of sexual abuse in children and adolescents, ...

  8. Critical Incident Reporting Systems: Perceived Competing Social ...

    African Journals Online (AJOL)

    The safe operation of complex socio-technical systems is dependent upon the reporting of safety critical incidents by operators within a system. Through the action of reporting, systems develop the capability as a learning organisation to improve human and organisational performance. The aim of the study is therefore to ...

  9. Incident response monitoring technologies for aircraft cabin

    NARCIS (Netherlands)

    Havermans, J.B.G.A.; Houtzager, M.M.G.; Jacobs, P.


    The Netherlands Organization for Applied Scientific Research (TNO) was granted by ASHRAE (1306-RP) to conduct scientfic review and feasibility analysis of technologies and methods for measuring aircraft power system contaminants in the cabin air during unanticipated adverse incidents. In particular,

  10. Incidence of childhood primary immune thrombocytopenic purpura. (United States)

    Higashigawa, Masamune; Maeyama, Takatoshi; Yoshino, Ayako; Matsuda, Kazuyuki; Ito, Mitsue; Maji, Tomoaki; Ichimi, Ryouji


    There is a discrepancy in the reported incidence of childhood immune thrombocytopenic purpura (ITP) between Europe (2.9-5.3 per 100 000 persons) and Japan (1.91). Ise district is a suitable area in which to conduct epidemiological study because there is little fluctuation in the sociodemographic factors. We performed a retrospective population-based study to clarify the incidence of primary childhood ITP. We calculated person-years for children aged <15 years based on the Ise district demographics between 2002 and 2012. The calculated person-years were 298 533. The number of hospitalized patients in Ise district was 25 (M/F, 14/11) during the study period. The calculated incidence was therefore 8.4 per 100 000 person-years. It is possible that the difference in incidence between the present calculation and that of the European studies is due to variation in accuracy and/or registration criteria between the studies. © 2015 Japan Pediatric Society.

  11. Incidence and Disability-Adjusted Life Years

    African Journals Online (AJOL)


    ABSTRACT. BACKGROUND: Leishmaniasis covers a range of clinical manifestations. Estimation of the burden of leishmaniasis may help guide healthcare management personnel and policy-makers in applying effective interventions. The present study aimed to calculate the incidence and burden of cutaneous and visceral.

  12. Incident Investigation in SMS and FRMS

    NARCIS (Netherlands)

    Stewart, S.; Koornneef, F.; Akselsson, R.; Kingston, J.; Stewart, D.


    Chapter 4: Incident Investigation in SMS and FRMS The European Commission HILAS project (Human Integration into the Lifecycle of Aviation Systems - a project supported by the European Commission’s 6th Framework between 2005-2009) was focused on using human factors knowledge and methodology to

  13. Incidence and Significance of Haematemesis in Cirrhosis

    African Journals Online (AJOL)


    Jun 8, 1974 ... tract (oesophageal varices) is an uncommon cause of death in patients with cirrhosis and portal hypertension. The view was that death occurs from liver failure per se more often than from haemorrhage, although opinion was not available as to whether this was because of a low incidence of haemorrhage ...

  14. Cancer incidence in Dutch Balkan veterans

    NARCIS (Netherlands)

    Bogers, R.P.; Leeuwen, F.E. van; Grievink, L.; Schouten, L.J.; Kiemeney, L.A.L.M.; Schram-Bijkerk, D.


    Suspicion has been raised about an increased cancer risk among Balkan veterans because of alleged exposure to depleted uranium. The authors conducted a historical cohort study to examine cancer incidence among Dutch Balkan veterans. Male military personnel (n=18,175, median follow-up 11 years) of

  15. IT Security Vulnerability and Incident Response Management

    NARCIS (Netherlands)

    Hafkamp, W.H.M.; Paulus, S.; Pohlman, N.; Reimer, H.


    This paper summarises the results of a Dutch PhD research project on IT security vulnerability and incident response management, which is supervised by the University of Twente in the Netherlands and which is currently in its final stage. Vulnerabilities are ‘failures or weaknesses in computer

  16. Organised Learning from Small-scale Incidents

    NARCIS (Netherlands)

    Koornneef, F.


    This thesis describes the search for and findings about methods and mechanisms that help organisations to learn cost-effectively from (small-scale) accidents and other undesired operational surprises. As it shows, organisational learning from such incidents is feasible, but must be organised. The

  17. reputation Risks through Information Security Incidents

    Directory of Open Access Journals (Sweden)

    Vitaly Eduardovich Dorokhov


    Full Text Available The article deals with accounting reputational risks arising through information security breaches in the management of a business entity. Security breach incidents which results to the loss of reputation are identified. Based on this analysis the definition of reputational risk in information security is given.

  18. Thyroid cancer incidence in Corsica. 1998 - 2006

    International Nuclear Information System (INIS)

    Pascal, Laurence; Lasalle, Jean-Luc


    In France, Corsica appears to be one of the most exposed regions to the fallout from the Chernobyl accident. Taking into account the scientific knowledge at that time, it was decided to focus studies on thyroid cancers. A study was carried out in order to estimate thyroid cancer incidence in Corsica for the periods 1998-2001 and 2002-2006. The study identified incident thyroid cancer cases between 1998 and 2006 among residents in Corsica. Data were collected using information from the hospitals (PMSI) and the local health insurance funds (ALD). Cases were validated through medical records before inclusion in the study. Over the period of study, 342 cases of thyroid cancer, rather women and relatively young patients, were identified in Corsica. Incidence rate of the thyroid cancer was high, but stable among men, and with a slight increase among women, particularly between 2002 and 2006. However, incidence rate and clinical characteristics of thyroid cancer in Corsica are not exceptional and are similar to those in other French districts. (authors)

  19. Urbanisation and the incidence of eating disorders.

    NARCIS (Netherlands)

    Son, G.E. van; Hoeken, D. van; Bartelds, A.I.M.; Furth, E.F. van; Hoek, H.W.


    The link between degree of urbanisation and a number of mental disorders is well established. Schizophrenia, psychosis and depression are known to occur more frequently in urban areas. In our primary care-based study of eating disorders, the incidence of bulimia nervosa showed a dose response

  20. Worldwide Increasing Incidences of Cutaneous Malignant Melanoma

    Directory of Open Access Journals (Sweden)

    Dianne E. Godar


    Full Text Available The incidence of cutaneous malignant melanoma (CMM has been increasing at a steady rate in fair-skinned populations around the world for decades. Scientists are not certain why CMM has been steadily increasing, but strong, intermittent UVB (290–320 nm exposures, especially sunburn episodes, probably initiate, CMM, while UVA (321–400 nm passing through glass windows in offices and cars probably promotes it. The CMM incidence may be increasing at an exponential rate around the world, but it definitely decreases with increasing latitude up to ~50°N where it reverses and increases with the increasing latitude. The inversion in the incidence of CMM may occur because there is more UVA relative to UVB for most of the year at higher latitudes. If windows, allowing UVA to enter our indoor-working environment and cars, are at least partly responsible for the increasing incidence of CMM, then UV filters can be applied to reduce the rate of increase worldwide.