WorldWideScience

Sample records for plastic spectacle lenses

  1. Aspherics in spectacle lenses

    Science.gov (United States)

    Dürsteler, Juan Carlos

    2016-12-01

    A review of the use of aspherics in the last decades, understood in a broad sense as encompassing single-vision lenses with conicoid surfaces and free-form and progressive addition lenses (PALs) as well, is provided. The appearance of conicoid surfaces to correct aphakia and later to provide thinner and more aesthetically appealing plus lenses and the introduction of PALs and free-form surfaces have shaped the advances in spectacle lenses in the last three decades. This document basically considers the main target optical aberrations, the idiosyncrasy of single lenses for correction of refractive errors and the restrictions and particularities of PAL design and their links to science vision and perception.

  2. Coatings and Tints of Spectacle Lenses

    OpenAIRE

    H. Zeki Büyükyıldız

    2012-01-01

    Spectacle lenses are made of mineral or organic (plastic) materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1) Anti-reflection coatings, 2) Hard coatings, 3) Clean coat, 4) Mirror coatings, 5) Color tint coating (one of coloring processes), 6) Photochromic coating (one of photochromic processes), and 7) Anti-fog...

  3. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  4. Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances.

    Science.gov (United States)

    Leung, Tsz Wing; Li, Roger Wing-Hong; Kee, Chea-Su

    2017-01-01

    To evaluate the optical performance of blue-light filtering spectacle lenses and investigate whether a reduction in blue light transmission affects visual performance and sleep quality. Experiment 1: The relative changes in phototoxicity, scotopic sensitivity, and melatonin suppression of five blue-light filtering plano spectacle lenses were calculated based on their spectral transmittances measured by a spectrophotometer. Experiment 2: A pseudo-randomized controlled study was conducted to evaluate the clinical performance of two blue-light filtering spectacle lenses (BF: blue-filtering anti-reflection coating; BT: brown-tinted) with a regular clear lens (AR) serving as a control. A total of eighty computer users were recruited from two age cohorts (young adults: 18-30 yrs, middle-aged adults: 40-55 yrs). Contrast sensitivity under standard and glare conditions, and colour discrimination were measured using standard clinical tests. After one month of lens wear, subjective ratings of lens performance were collected by questionnaire. All tested blue-light filtering spectacle lenses theoretically reduced the calculated phototoxicity by 10.6% to 23.6%. Although use of the blue-light filters also decreased scotopic sensitivity by 2.4% to 9.6%, and melatonin suppression by 5.8% to 15.0%, over 70% of the participants could not detect these optical changes. Our clinical tests revealed no significant decrease in contrast sensitivity either with (95% confidence intervals [CI]: AR-BT [-0.05, 0.05]; AR-BF [-0.05, 0.06]; BT-BF [-0.06, 0.06]) or without glare (95% CI: AR-BT [-0.01, 0.03]; AR-BF [-0.01, 0.03]; BT-BF [-0.02, 0.02]) and colour discrimination (95% CI: AR-BT [-9.07, 1.02]; AR-BF [-7.06, 4.46]; BT-BF [-3.12, 8.57]). Blue-light filtering spectacle lenses can partially filter high-energy short-wavelength light without substantially degrading visual performance and sleep quality. These lenses may serve as a supplementary option for protecting the retina from potential

  5. 21 CFR 886.5842 - Spectacle frame.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spectacle frame. 886.5842 Section 886.5842 Food... DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5842 Spectacle frame. (a) Identification. A spectacle frame is a device made of metal or plastic intended to hold prescription spectacle lenses worn by...

  6. Photographic simulation of off-axis blurring due to chromatic aberration in spectacle lenses.

    Science.gov (United States)

    Doroslovački, Pavle; Guyton, David L

    2015-02-01

    Spectacle lens materials of high refractive index (nd) tend to have high chromatic dispersion (low Abbé number [V]), which may contribute to visual blurring with oblique viewing. A patient who noted off-axis blurring with new high-refractive-index spectacle lenses prompted us to do a photographic simulation of the off-axis aberrations in 3 readily available spectacle lens materials, CR-39 (nd = 1.50), polyurethane (nd = 1.60), and polycarbonate (nd = 1.59). Both chromatic and monochromatic aberrations were found to cause off-axis image degradation. Chromatic aberration was more prominent in the higher-index materials (especially polycarbonate), whereas the lower-index CR-39 had more astigmatism of oblique incidence. It is important to consider off-axis aberrations when a patient complains of otherwise unexplained blurred vision with a new pair of spectacle lenses, especially given the increasing promotion of high-refractive-index materials with high chromatic dispersion.

  7. [Spectacle lenses in sports: optimization of the imaging properties based on physiological aspects].

    Science.gov (United States)

    Becken, Wolfgang; Seidemann, Anne; Altheimer, Helmut; Esser, Gregor; Uttenweiler, Dietmar

    2007-01-01

    The goal of correction spectacles is to create a sharp image on the retina by the combined optical system of the eye and the spectacle lens for a given ametropia. As a matter of principle, in this optical system an aberration free correction can be achieved in the optical centre of the spectacle lens, but not over the entire range of gaze angles. In spectacle optics large angles play an important role, different from paraxial optics where only rays close to the axis with small angles of incidence are relevant. This generates additional aberrations, the so-called oblique astigmatism, which can only be compensated at the expense of the spherical power. Therefore, every spectacle lens represents apart from the main visual point-, a more or less good compromise. For sports lenses in the currently used curved frames, an additional challenge arises from the fact that their orientation in front of the eye is generally not perpendicular to the principal gaze direction but tilted. In this article the imaging properties of such tilted sports lenses are discussed, and it is described why this results in a minor quality without a specific consideration of the obliqueness. The fact that tilted sports spectacles are also able to possess an improved correction behaviour for all gaze angles is due to individual mathematical optimization methods. The aim of the present article is, based on the underlying physical and physiological effects, to point out the advantages of individually optimized sports spectacle lenses in comparison to tilted lenses generated without applying this sophisticated computational method.

  8. Progress in the spectacle correction of presbyopia. Part 1: Design and development of progressive lenses.

    Science.gov (United States)

    Meister, Darryl J; Fisher, Scott W

    2008-05-01

    Most of the commercial advances in the spectacle correction of presbyopia continue to occur in progressive lens design, which has been the focus of intense research and development over the past 60 years by major spectacle lens manufacturers. While progressive lens design and manufacturing techniques have advanced at a steady pace, recent progress in 'free-form' lens surfacing has opened up many exciting possibilities that will in all likelihood bring about a paradigm shift in the current model of progressive lens fabrication and distribution. The first installment of this two-part series will review the fundamental optical principles and early development work associated with progressive lenses.

  9. Visual function improvement using photocromic and selective blue-violet light filtering spectacle lenses in patients affected by retinal diseases

    National Research Council Canada - National Science Library

    L Colombo; E Melardi; P Ferri; G Montesano; S Samir Attaalla; F Patelli; S De Cilla; G Savaresi; L Rossetti

    2017-01-01

    Background To evaluate functional visual parameters using photocromic and selective blue-violet light filtering spectacle lenses in patients affected by central or peripheral scotoma due to retinal diseases...

  10. Spectacle

    CERN Multimedia

    Spectacle

    2010-01-01

    Du 4 au 8 décembre 2010 à l'Alhambra de Genève   Créée et mise en scène par des acteurs et chanteurs professionnels, cette comédie musicale dynamique est une première en Suisse. Elle est destinée particulièrement aux enfants entre 4 et 10 ans. Dans un spectacle dynamique, intelligeant et haut en couleurs, retrouvez les aventures de Rosalie… petite souris bien malicieuse qui va faire sa première rentrée à l'école et rêve de devenir une star de la chanson! Chacun des personnages permet à l’enfant de s’identifier à l’un d’entre eux ; tous ont des caractéristiques très humaines. Ainsi, les différentes scènes transportent les jeunes spectateurs à vibrer de la même façon que les acteurs. De ...

  11. Spectacle

    CERN Multimedia

    Spectacle

    2010-01-01

    Du 4 au 8 décembre 2010 à l'Alhambra de Genève   Créée et mise en scène par des acteurs et chanteurs professionnels, cette comédie musicale dynamique est une première en Suisse. Elle est destinée particulièrement aux enfants entre 4 et 10 ans. Dans un spectacle dynamique, intelligeant et haut en couleurs, retrouvez les aventures de Rosalie… petite souris bien malicieuse qui va faire sa première rentrée à l'école et rêve de devenir une star de la chanson! Chacun des personnages permet à l’enfant de s’identifier à l’un d’entre eux ; tous ont des caractéristiques très humaines. Ainsi, les différentes scènes transportent les jeunes spectateurs à vibrer de la même façon que les acteurs. De ...

  12. Wavefront measurement of plastic lenses for mobile-phone applications

    Science.gov (United States)

    Huang, Li-Ting; Cheng, Yuan-Chieh; Wang, Chung-Yen; Wang, Pei-Jen

    2016-08-01

    In camera lenses for mobile-phone applications, all lens elements have been designed with aspheric surfaces because of the requirements in minimal total track length of the lenses. Due to the diffraction-limited optics design with precision assembly procedures, element inspection and lens performance measurement have become cumbersome in the production of mobile-phone cameras. Recently, wavefront measurements based on Shack-Hartmann sensors have been successfully implemented on injection-molded plastic lens with aspheric surfaces. However, the applications of wavefront measurement on small-sized plastic lenses have yet to be studied both theoretically and experimentally. In this paper, both an in-house-built and a commercial wavefront measurement system configured on two optics structures have been investigated with measurement of wavefront aberrations on two lens elements from a mobile-phone camera. First, the wet-cell method has been employed for verifications of aberrations due to residual birefringence in an injection-molded lens. Then, two lens elements of a mobile-phone camera with large positive and negative power have been measured with aberrations expressed in Zernike polynomial to illustrate the effectiveness in wavefront measurement for troubleshooting defects in optical performance.

  13. Johannes Amos Comenius (1592-1670) and his depiction of lenses and spectacles in the first children's picture book.

    Science.gov (United States)

    Goss, David A

    2009-01-01

    Johannes Amos Comenius (1592-1670) was a Moravian clergyman, teacher, and author. He is recognized as introducing several concepts of modern education. He advanced the views that education should be appropriate to age and development levels and that teaching should make use of everyday sensory experience. One of his many books, Orbis Pictus, followed those concepts. Orbis Pictus, first published in 1657, is hailed as the first children's picture book. Among the many commonplace objects he included in the book were a mirror, spectacles, a telescope, a magnifying lens, and a burning glass.

  14. Large-scale optical diffraction tomography for inspection of optical plastic lenses

    CERN Document Server

    Kim, Kyoohyun; Park, YongKeun

    2015-01-01

    Herein is presented an optical diffraction tomography (ODT) technique for measuring 3-D refractive index (RI) maps of optical plastic lenses. A Mach-Zehnder interferometer was used to measure multiple complex optical fields of a plastic lens immersed in RI matching oil, at various rotational orientations. From this, ODT was used to reconstruct a 3-D RI distribution of the plastic lens with unprecedented RI sensitivity (dn = 4.21 x 10^-5) and high resolution (12.8 um). As a demonstration, 3-D RI distributions of a 2-mm-diameter borosilicate sphere and a 5-mm-diameter plastic lens

  15. Desempenho visual na correção de miopia com óculos e lentes de contato gelatinosas Visual performance in myopic correction with spectacles and soft contact lenses

    Directory of Open Access Journals (Sweden)

    Breno Barth

    2008-02-01

    with three different soft contact lenses [Acuvue® 2 (Vistacon J&J Vision Care Inc., USA, Biomedics® 55 (Ocular Science, USA, and Focus® 1-2 week (Ciba Vision Corporation, USA]. METHODS: An interventional prospective clinical trial studied a sample of 40 myopic patients (-1.00 to -4.50 sph, with or without astigmatism up to -0.75 cyl. Each patient had one eye randomized to visual performance evaluation. RESULTS: The Zywave aberrometer detected a over refraction and significant difference between Acuvue® 2 and Biomedics® 55 regarding spheric refractive components and spheric equivalent. Both soft contact lenses showed hypercorrection as compared to Focus® 1-2 week. Visual performance was not significantly different with spectacles and the three soft contact lenses in visual acuity and contrast sensitivity measurements. The wavefront analysis detected a significant difference in a third order aberration with and without soft contact lenses, with better visual performance with Acuvue® 2 and Biomedics® 55. CONCLUSION: In visual performance evaluation with spectacles and soft contact lenses the wavefront analysis was a more sensible measurement of visual function when compared to high contrast visual acuity and contrast sensitivity. The evaluation model of visual performance with wavefront analysis developed in this investigation may be useful for further similar studies.

  16. In-line polariscopic checking of plastic molded-injected lenses: preliminary results

    Science.gov (United States)

    Arasa, J.; Mayershofer, D.; Romero, J.

    2015-05-01

    Plastic injection molded lenses have improved its performance and, nowadays, are as usual as glass lenses in image forming devices. However, the manufacturing process induces the surface generation and the material transformation in the same stage. Moreover, the process also includes an annealing stage to remove the internal stress with temperature cycles but only works up to a certain level and not beyond, leaving relevant traces for high values. During the manufacturing process of a plastic lens, a liquid-solid phase transformation occurs, and in this transition not all the volume of the lens achieves the same density. This change of density is translated into a local change of refractive index that can be expressed as a retardation phase plane using the Jones Matrix notation. The detection and measurement of the value of the retardation of the phase plane is thus the clue to manufacture good and controlled quality plastic lenses. We have tested an in-line polariscopic arrangement to obtain a 2D map of the tension distribution in the bulk of the lens. This test is performed in the first 30 seconds after the injection molding process for two main reasons: first the stress values are still high because the lenses do not have enough time to relax the internal tensions and obtain the final shape, and second, we can remove the wrong lenses in the first moments and introduce only the good lenses in the annealing stage. The proposed instrument is based in a transmission polariscopic arrangement. A collimated light beam is used to illuminate the sample, once the light crosses the sample, it is collected with an afocal system and the image is recorded in a CMOS sensor. Selecting an afocal system to capture the image is a useful decision because the lateral magnification can be maintained when small changes in the sample position are introduced. However the produced lenses can vary their focal lengths from on series to another. To avoid problems with the change of the

  17. Simulation of imperfections in plastic lenses - transferring local refractive index changes into surface shape modifications

    Science.gov (United States)

    Arasa, Josep; Pizarro, Carles; Blanco, Patricia

    2016-06-01

    Injection molded plastic lenses have continuously improved their performance regarding optical quality and nowadays are as usual as glass lenses in image forming devices. However, during the manufacturing process unavoidable fluctuations in material density occur, resulting in local changes in the distribution of refractive index, which degrade the imaging properties of the polymer lens. Such material density fluctuations correlate to phase delays, which opens a path for their mapping. However, it is difficult to transfer the measured variations in refractive index into conventional optical simulation tool. Thus, we propose a method to convert the local variations in refractive index into local changes of one surface of the lens, which can then be described as a free-form surface, easy to introduce in conventional simulation tools. The proposed method was tested on a commercial gradient index (GRIN) lens for a set of six different object positions, using the MTF sagittal and tangential cuts to compare the differences between the real lens and a lens with homogenous refractive index, and the last surface converted into a free-form shape containing the internal refractive index changes. The same procedure was used to reproduce the local refractive index changes of an injected plastic lens with local index changes measured using an in-house built polariscopic arrangement, showing the capability of the method to provide successful results.

  18. Comparison of accommodative lag in pre-adolescent myopes one year after wearing rigid gas permeable contact lenses, orthokeratology lenses or spectacles%青少年近视眼配戴RGPCL、Ortho-K及框架眼镜一年后调节滞后的差异

    Institute of Scientific and Technical Information of China (English)

    黄佳; 瞿小妹; 陈志; 褚仁远

    2010-01-01

    Objective To discuss the differences in accommodative lag between pre-adolescent myopes who wore rigid gas permeable contact lenses (RGPCL), orthokeratology (Ortho-K) lenses or spectacles for a year. Methods Seventy pre-adolescent myopes aged 9 to 14 years were enrolled in the study. Every subject was measured for refraction with MPMVA, corneal curvature radius and corneal topography. Twenty-five subjects were selected to wear RGPCL, 25 subjects were chosen to wear Ortho-K lenses and the other 20 subjects wore spectacles. According to the above measurements and the compliance of children and their parents. Regular after-care visits were made at 3-month in- tervals. Accommodative response (AR) was measured with an open field infrared autorefractor (WAM- 5500) in accommodative stimulus (AS) level of 2~5 D after one year. Accommodative lag and the AR/ AS slope were calculated by statistical methods. Results Fifty-seven subjects completed the experi- ment. The results demonstrate no significant difference in accommodative lag between RGPCL, Ortho- K lens and spectacle wearers for the 2 D AS level (P>0.05), while for the 3 D, 4 D and 5 D AS levels, there were significant differences in accommodative lag among the three groups (F=4.373, P0.05). Conclusion Compared to spectacles, there is an obvious decrease in accommodative lag in pre-adolescent myopes one year after wearing RGPCL and Ortho-K lenses, which strongly suggests that RGPCL and Ortho-K lenses can control the development of myopia in pre-adoleseents.%目的 探讨青少年近视眼配戴硬性透气性角膜接触镜(rigid gas permeable contact lens,RGPCL)、角膜塑型镜(orthokeratology,Ortho-K,OK镜)及框架眼镜后调节滞后的差异.方法 70名(70眼)9~14岁中低度青少年近视眼患儿,行医学验光、角膜曲率、角膜地形图检查后,根据检查结果、患儿及家长依从性等综合评估,对其中25名患儿选择配戴RGPCL,25名患儿配戴Ortho-K,其余20名患儿配

  19. Visual Performance in Moderate to Severe Astigmatism : Rigid Gas-permeable Contact Lenses versus Spectacles%透气性硬性接触镜和框架眼镜矫正中高度散光视觉质量的比较

    Institute of Scientific and Technical Information of China (English)

    王雪; 马薇; 杨必; 刘陇黔

    2012-01-01

    Objective To explore whether spectacles or rigid gas-permeable (RGP) contact lenses provide better visual performance for moderate to severe astigmatism. Methods Between June 2008 and May 2011, 20 individuals (40 eyes) were fitted with both RGP lenses and spectacles. They first underwent corneal topography and refractometry, then were fitted with RGP trial lenses and lastly fitted with RGP lenses. When regularly followed up, the corrected visual acuity, wearing condition and eye health were evaluated respectively. For each type of lens, contrast visual acuity was evaluated. Each subject was asked to select the lens type of choice and to rate quality of vision in day-to-day activities through a questionnaire. Results The corrected visual acuity with RGP lenses was better than that with spectacles. But there was no difference in contrast visual acuity in all spatial frequency. Subjectively, there was no difference in vision, but most of the subjects prefer the computer-visual acuity and reading-visual acuity corrected by spectacles. About 40% of patients choose RGP contact lens as the main corrected method, and 45% of patients preferred using RGP lenses and spectacles alternately. About 10% of patients only wear RGP lenses when it was necessary. Two patients dropped out. Conclusions Both RGP lenses and spectacles leads to good results in correcting moderate to severe astigmatism. Though spectacles get higher scores in near vision, because of the better visual performance and appearance offered by RGP contact lens, a majority of patients can insist on wearing it.%目的 比较中高度散光患者配戴框架眼镜和透气性硬性接触镜(RGPCL)的主客观视觉质量.方法 选取2008年6月-2011年5月中高度角膜散光20例共40只眼进行角膜地形图、综合验光仪验光等检查后,选择合适试戴片作配适评估并定制RGPCL.要求患者戴镜后1周、1个月、3个月和6个月复查,记录矫正视力、镜片配

  20. Comparative Evaluation of Ultraviolet and Visible Light Transmittance through Prescriptive Ophthalmic Minus Lenses

    Directory of Open Access Journals (Sweden)

    Mohammadreza Nazari

    2014-06-01

    Full Text Available Background: Wearing spectacles is the most common approach in correcting the refractive errors worldwide. Due to harmful effects of overexposure to solar ultraviolet radiations, the usage of multi-layer coatings in ophthalmic lenses has recently been increased. These lenses can reduce the reflections and hence increase the transmission of visible light; they can also decrease the transmission of ultraviolet rays. This study aims to compare the transmission of ultraviolet (A and B and visible rays through coated and uncoated prescriptive ophthalmic plastic lenses.Materials and Methods: In this study, 39 minus non-photochromic multi-coated white plastic single-vision lenses; 9 similar lenses but without any coatings were assessed by spectral transmittancemeter for evaluation of the transmission of visible and ultraviolet rays.Results: The transmission of visible light was 97.9%±1.07% for coated lenses and 93.5%±0.54% for lenses without coating. Ultraviolet-A transmission was 12.15%±8.02% for coated lenses compared to 66.27%±23.92% in lenses without coating. The transmission of ultraviolet-B rays was 1.21%±0.4% and 23.0%±15.97% for lenses with and without coatings, respectively.Conclusion: The transmission of visible light was significantly higher in multi-coated lenses compared to uncoated samples; whereas the transmissions of ultraviolet rays in multi-coated lenses were significantly lower than uncoated ones. Therefore, it is recommended that, except for particular cases, prescribed lenses be equipped with this multi-layer coating.

  1. A method for the prescription of inexpensive spectacles by non-specialist healthcare workers: S-Glasses.

    LENUS (Irish Health Repository)

    Treacy, M P

    2013-04-01

    Globally, 153 million people are visually impaired from uncorrected refractive error. The aim of this research was to verify a method whereby autorefractors could be used by non-specialist health-workers to prescribe spectacles, which used a small stock of preformed lenses that fit frames with standardised apertures. These spectacles were named S-Glasses (Smart Glasses).

  2. A Comparison of Spectacles Purchased Online and in UK Optometry Practice

    Science.gov (United States)

    Alderson, Alison J.; Green, Alison; Whitaker, David; Scally, Andrew J.; Elliott, David B.

    2016-01-01

    ABSTRACT Purpose To compare spectacles bought online with spectacles from optometry practices. Methods Thirty-three participants consisting of single vision spectacle wearers with either a low (N = 12, mean age 34 ± 14 years) or high prescription (N = 11, mean age 28 ± 9 years) and 10 presbyopic participants (mean age 59 ± 4 years) wearing progressive addition lenses (PALs) purchased 154 pairs of spectacles online and 154 from UK optometry practices. The spectacles were compared via participant-reported preference, acceptability, and safety; the assessment of lens, frame, and fit quality; and the accuracy of the lens prescriptions to international standard ISO 21987:2009. Results Participants preferred the practice spectacles (median ranking 4th, IQR 1–6) more than online (6th, IQR 4–8; Mann-Whitney U = 7345, p < 0.001) and practice PALs (median ranking 2nd, IQR 1–4) were particularly preferred (online 6.5th, IQR 4–9, Mann-Whitney U = 455, p < 0.001). Of those deemed unacceptable and unsafe, significantly more were bought online (unacceptable: online 43/154 vs. practice 15/154, Fisher’s exact p = 0.0001; unsafe: online 14/154 vs. practice 5/154, Fisher’s exact p = 0.03). Conclusions Participants preferred spectacles from optometry practice rather than those bought online, despite lens quality and prescription accuracy being similar. A greater number of online spectacles were deemed unsafe or unacceptable because of poor spectacle frame fit, poor cosmetic appearance, and inaccurate optical centration. This seems particularly pertinent to PAL lenses, which are known to increase falls risk. Recommendations are made to improve both forms of spectacle provision. PMID:27536974

  3. The Power of Spectacle

    Directory of Open Access Journals (Sweden)

    Anna Greenspan

    2012-01-01

    Full Text Available When people say Shanghai looks like the future the setting is almost always the same. Evening descends and the skyscrapers clustered on the eastern shore of the Huangpu light up. Super towers are transformed into giant screens. The spectacular skyline, all neon and lasers and LED, looms as a science fiction backdrop. Staring out from the Bund, across to Pudong, one senses the reemergence of what JG Ballard once described as an ”electric and lurid city, more exciting than any other in the world.” The high-speed development of Pudong – in particular the financial district of Lujiazui – is the symbol of contemporary Shanghai and of China’s miraculous rise.Yet, Pudong is also taken as a sign of much that is wrong with China’s new urbanism. To critics the sci-fi skyline is an emblem of the city’s shallowness, which focuses all attention on its glossy facade. Many share the sentiment of free market economist Milton Friedman who, when visiting Pudong famously derided the brand new spectacle as a giant Potemkin village. Nothing but “the statist monument for a dead pharaoh,” he is quoted as saying.This article explores Pudong in order to investigate the way spectacle functions in China’s most dynamic metropolis. It argues that the skeptical hostility towards spectacle is rooted in the particularities of a Western philosophical tradition that insists on penetrating the surface, associating falsity with darkness and truth with light.In contrast, China has long recognized the power of spectacle (most famously inventing gunpowder but using it only for fireworks. Alongside this comes an acceptance of a shadowy world that belongs to the dark. This acknowledgment of both darkness and light found in traditional Chinese culture (expressed by the constant revolutions of the yin/yang symbol may provide an alternative method for thinking about the tension between the spectacular visions of planners and the unexpected and shadowy disruptions from

  4. Continuously adjustable Pulfrich spectacles

    Science.gov (United States)

    Jacobs, Ken; Karpf, Ron

    2011-03-01

    A number of Pulfrich 3-D movies and TV shows have been produced, but the standard implementation has inherent drawbacks. The movie and TV industries have correctly concluded that the standard Pulfrich 3-D implementation is not a useful 3-D technique. Continuously Adjustable Pulfrich Spectacles (CAPS) is a new implementation of the Pulfrich effect that allows any scene containing movement in a standard 2-D movie, which are most scenes, to be optionally viewed in 3-D using inexpensive viewing specs. Recent scientific results in the fields of human perception, optoelectronics, video compression and video format conversion are translated into a new implementation of Pulfrich 3- D. CAPS uses these results to continuously adjust to the movie so that the viewing spectacles always conform to the optical density that optimizes the Pulfrich stereoscopic illusion. CAPS instantly provides 3-D immersion to any moving scene in any 2-D movie. Without the glasses, the movie will appear as a normal 2-D image. CAPS work on any viewing device, and with any distribution medium. CAPS is appropriate for viewing Internet streamed movies in 3-D.

  5. Elimination of aniseikonia in monocular aphakia with a contact lens-spectacle combination.

    Science.gov (United States)

    Schechter, R J

    1978-01-01

    Correction of monocular aphakia with contact lenses generally results in aniseikonia in the range of 7--9%; with correction by intraocular lenses, aniseikonia is approximately 2%. We present a new method of correcting aniseikonia in monocular aphakics using a contact lens-spectacle combination. A formula is derived wherein the contact lens is deliberately overcorrected; this overcorrection is then neutralized by the appropriate spectacle lens, to be worn over the contact lens. Calculated results with this system over a wide range of possible situations consistently results in an aniseikonia of 0.1%.

  6. Non-destructive method of measuring the refractive index of spectacle lenses based on Gauss-Newton iterative method%基于高斯牛顿迭代法的无损检测眼镜镜片折射率方法

    Institute of Scientific and Technical Information of China (English)

    侯蕊

    2015-01-01

    In view of the traditional destructive method for measuring the refractive index of spectacle lenses, a non-destructive method was proposed by measuring the lens’ transmittance and fitting the curve by Gauss-Newton iterative method. The experimental results showed that the non-destructive method could measure the refractive index quickly, and the relative error was less than±1%, and the measurement accuracy could basically met the judgement of the lens refractive index.%针对传统测量眼镜镜片折射率的有损方法,提出通过测量眼镜镜片透射比,采用高斯牛顿迭代法拟合透射比曲线来无损检测眼镜镜片基底折射率。实验结果表明,此无损检测方法可快速检测镜片折射率,测量相对误差不超过±1%,基本满足对镜片折射率区间的判定。

  7. Antireflection coatings on plastics deposited by plasma polymerization process

    Indian Academy of Sciences (India)

    K M K Srivatsa; M Bera; A Basu; T K Bhattacharya

    2008-08-01

    Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage process—exposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

  8. Gold plating on spectacle frames.

    Science.gov (United States)

    Kenny, I; Mitchell, J W; Walsh, G

    1997-05-01

    An investigation was carried out into the thickness and standard of application of the plating and lacquer coatings applied to three metal spectacle frames. All conform to BS 6625 (1991) for plating thickness, but there was considerable variation in regularity and porosity.

  9. Vascularity in the reptilian spectacle.

    Science.gov (United States)

    Mead, A W

    1976-07-01

    Vascularization of the spectacle or brille of the reptile was demonstrated by biomicroscopy, histology, fluorescein (in vivo), and Microfil silicone rubber (in situ) injections. This unusual vascularity provides new evidence for reassessment of the origin and development of this structure, and a useful tool with which to do so.

  10. Triethylene glycol bis(2-ethylhexanoate) - a new contact allergen identified in a spectacle frame

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Vestergaard, M. E.; Christensen, Lars Porskjær

    2014-01-01

    in this patient's spectacle frame. Materials and methods. An extract from the temple arms was analysed by gas chromatography mass spectrometry (GC-MS), and a major low molecular weight compound was detected. This compound was isolated by semi-preparative high-performance liquid chromatography and identified by GC......Background. Allergic reactions to spectacle frames are not unusual. A patient had a reproducible strong allergic patch test reaction to scrapings from the plastic material, and negative patch test results with available spectacle frame chemicals. Objectives. To identify the culprit allergen...... bis(2-ethylhexanoate) was the causative allergen in the spectacle frame. Ten consecutive eczema patients tested as controls were negative. Conclusion. Triethylene glycol bis(2-ethylhexanoate) is a new, hitherto unreported contact allergen....

  11. Character Education, New Media, and Political Spectacle

    Science.gov (United States)

    Winton, Sue

    2010-01-01

    Ontario's new Character Development Initiative is analyzed to determine whether it can be characterized as political spectacle. Examination of official policy texts, media reports, speeches, web pages, webcasts, and events at the Character Development Symposium suggests that the Initiative contains many elements of political spectacle; however,…

  12. Blood flow dynamics in the snake spectacle.

    Science.gov (United States)

    van Doorn, Kevin; Sivak, Jacob G

    2013-11-15

    The eyes of snakes are shielded beneath a layer of transparent integument referred to as the 'reptilian spectacle'. Well adapted to vision by virtue of its optical transparency, it nevertheless retains one characteristic of the integument that would otherwise prove detrimental to vision: its vascularity. Given the potential consequence of spectacle blood vessels on visual clarity, one might expect adaptations to have evolved that mitigate their negative impact. Earlier research demonstrated an adaptation to their spatial layout in only one species to reduce the vessels' density in the region serving the foveal and binocular visual fields. Here, we present a study of spectacle blood flow dynamics and provide evidence of a mechanism to mitigate the spectacle blood vessels' deleterious effect on vision by regulation of blood flow through them. It was found that when snakes are at rest and undisturbed, spectacle vessels undergo cycles of dilation and constriction, such that the majority of the time the vessels are fully constricted, effectively removing them from the visual field. When snakes are presented with a visual threat, spectacle vessels constrict and remain constricted for longer periods than occur during the resting cycles, thus guaranteeing the best possible visual capabilities in times of need. Finally, during the snakes' renewal phase when they are generating a new stratum corneum, the resting cycle is abolished, spectacle vessels remain dilated and blood flow remains strong and continuous. The significance of these findings in terms of the visual capabilities and physiology of snakes is discussed.

  13. Effects of wearing yellow spectacles on visual skills, reading speed, and visual symptoms in children with reading difficulties.

    Science.gov (United States)

    Palomo-Álvarez, Catalina; Puell, María C

    2013-03-01

    Possible beneficial effects of yellow-tinted spectacle lenses on binocular vision, accommodation, oculomotor scanning, reading speed and visual symptoms were assessed in children with reading difficulties. A longitudinal prospective study was performed in 82 non-dyslexic children with reading difficulties in grades 3-6 (aged 9-11 years) from 11 elementary schools in Madrid (Spain). The children were randomly assigned to two groups: a treatment (n = 46) and a without-treatment group (n = 36). Children in the treatment group wore yellow spectacle lenses with best correction if necessary over 3 months (in school and at home). The tests were first undertaken without the yellow filter. With best spectacle correction in each subject, measurements were made of: distance and near horizontal heterophoria, distance and near horizontal fusional vergence ranges, the accommodative convergence/accommodation (AC/A) ratio, near point of convergence (NPC), stereoacuity, negative relative accommodation (NRA) and positive relative accommodation (PRA), monocular accommodative amplitude (MAA), binocular accommodative facility (BAF), oculomotor scanning, and reading speed (words per minute). The Convergence Insufficiency Symptom Survey (CISS) questionnaire was completed by all children. After the 3-month period, measurements were repeated with the yellow lenses (treatment group) or without the yellow lenses (without-treatment group) but with refractive correction if needed. Over the 3 months, the two groups showed similar mean changes in the variables used to assess binocular vision, accommodation, oculomotor scanning, and reading speed. However, mean relative changes in convergence insufficiency symptoms differed significantly between the groups (p = 0.01). No effects of wearing yellow spectacles emerged on binocular vision, accommodation, oculomotor scanning, and reading speed in children with reading difficulties. The yellow filter had no effect even in children with low MAA and BAF

  14. Computer vision syndrome in presbyopia and beginning presbyopia: effects of spectacle lens type.

    Science.gov (United States)

    Jaschinski, Wolfgang; König, Mirjam; Mekontso, Tiofil M; Ohlendorf, Arne; Welscher, Monique

    2015-05-01

    This office field study investigated the effects of different types of spectacle lenses habitually worn by computer users with presbyopia and in the beginning stages of presbyopia. Computer vision syndrome was assessed through reported complaints and ergonomic conditions. A questionnaire regarding the type of habitually worn near-vision lenses at the workplace, visual conditions and the levels of different types of complaints was administered to 175 participants aged 35 years and older (mean ± SD: 52.0 ± 6.7 years). Statistical factor analysis identified five specific aspects of the complaints. Workplace conditions were analysed based on photographs taken in typical working conditions. In the subgroup of 25 users between the ages of 36 and 57 years (mean 44 ± 5 years), who wore distance-vision lenses and performed more demanding occupational tasks, the reported extents of 'ocular strain', 'musculoskeletal strain' and 'headache' increased with the daily duration of computer work and explained up to 44 per cent of the variance (rs = 0.66). In the other subgroups, this effect was smaller, while in the complete sample (n = 175), this correlation was approximately rs = 0.2. The subgroup of 85 general-purpose progressive lens users (mean age 54 years) adopted head inclinations that were approximately seven degrees more elevated than those of the subgroups with single vision lenses. The present questionnaire was able to assess the complaints of computer users depending on the type of spectacle lenses worn. A missing near-vision addition among participants in the early stages of presbyopia was identified as a risk factor for complaints among those with longer daily durations of demanding computer work. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

  15. Perception of faces with and without spectacles.

    Science.gov (United States)

    McKelvie, S J

    1997-04-01

    For 20 faces, 85 subjects selected either a distinctive feature or a distinctive trait. For faces with spectacles, the eyes were judged to be most prominent, and the people were judged to be dull and intelligent. Results are discussed in terms of the physical attractiveness stereotype.

  16. Triphenyl phosphate allergy from spectacle frames

    DEFF Research Database (Denmark)

    Carlsen, L; Andersen, K E; Egsgaard, Helge

    1986-01-01

    A case of triphenyl phosphate allergy from spectacle frames is reported. Patch tests with analytical grade triphenyl phosphate, tri-m-cresyl phosphate, and tri-p-cresyl phosphate in the concentrations 5%, 0.5% and 0.05% pet. showed positive reactions to 0.05% triphenyl phosphate and 0.5% tri-m-cr...

  17. UV-blocking spectacle lens protects against UV-induced decline of visual performance

    Science.gov (United States)

    Liou, Jyh-Cheng; Teng, Mei-Ching; Tsai, Yun-Shan; Lin, En-Chieh

    2015-01-01

    Purpose Excessive exposure to sunlight may be a risk factor for ocular diseases and reduced visual performance. This study was designed to examine the ability of an ultraviolet (UV)-blocking spectacle lens to prevent visual acuity decline and ocular surface disorders in a mouse model of UVB-induced photokeratitis. Methods Mice were divided into 4 groups (10 mice per group): (1) a blank control group (no exposure to UV radiation), (2) a UVB/no lens group (mice exposed to UVB rays, but without lens protection), (3) a UVB/UV400 group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [UV400 coating]), and (4) a UVB/photochromic group (mice exposed to UVB rays and protected using the CR-39™ spectacle lens [photochromic coating]). We investigated UVB-induced changes in visual acuity and in corneal smoothness, opacity, and lissamine green staining. We also evaluated the correlation between visual acuity decline and changes to the corneal surface parameters. Tissue sections were prepared and stained immunohistochemically to evaluate the structural integrity of the cornea and conjunctiva. Results In blank controls, the cornea remained undamaged, whereas in UVB-exposed mice, the corneal surface was disrupted; this disruption significantly correlated with a concomitant decline in visual acuity. Both the UVB/UV400 and UVB/photochromic groups had sharper visual acuity and a healthier corneal surface than the UVB/no lens group. Eyes in both protected groups also showed better corneal and conjunctival structural integrity than unprotected eyes. Furthermore, there were fewer apoptotic cells and less polymorphonuclear leukocyte infiltration in corneas protected by the spectacle lenses. Conclusions The model established herein reliably determines the protective effect of UV-blocking ophthalmic biomaterials, because the in vivo protection against UV-induced ocular damage and visual acuity decline was easily defined. PMID:26283865

  18. Thin-film optical notch filter spectacle coatings for the treatment of migraine and photophobia

    Science.gov (United States)

    Hoggan, Ryan N.; Subhash, Amith; Blair, Steve; Digre, Kathleen B.; Baggaley, Susan K.; Gordon, Jamison; Brennan, K.C.; Warner, Judith E.A.; Crum, Alison V.; Katz, Bradley J.

    2017-01-01

    Previous evidence suggests optical treatments hold promise for treating migraine and photophobia. We designed an optical notch filter, centered at 480 nm to reduce direct stimulation of intrinsically photosensitive retinal ganglion cells. We used thin-film technology to integrate the filter into spectacle lenses. Our objective was to determine if an optical notch filter, designed to attenuate activity of intrinsically photosensitive retinal ganglion cells, could reduce headache impact in chronic migraine subjects. For this randomized, double-masked study, our primary endpoint was the Headache Impact Test (HIT-6; GlaxoSmithKline, Brentford, Middlesex, UK). We developed two filters: the therapeutic filter blocked visible light at 480 nm; a 620 nm filter was designed as a sham. Participants were asked to wear lenses with one of the filters for 2 weeks; after 2 weeks when no lenses were worn, they wore lenses with the other filter for 2 weeks. Of 48 subjects, 37 completed the study. Wearing either the 480 or 620 nm lenses resulted in clinically and statistically significant HIT-6 reductions. However, there was no significant difference when comparing overall effect of the 480 and 620 nm lenses. Although the 620 nm filter was designed as a sham intervention, research published following the trial indicated that melanopsin, the photopigment in intrinsically photosensitive retinal ganglion cells, is bi-stable. This molecular property may explain the unexpected efficacy of the 620 nm filter. These preliminary findings indicate that lenses outfitted with a thin-film optical notch filter may be useful in treating chronic migraine. PMID:26935748

  19. HEALTH INSURANCE Spectacle frame reimbursement ceiling

    CERN Multimedia

    HR Division

    2001-01-01

    As from 1st January 2001, the three-year reimbursement ceiling for spectacle frames is replaced by annual ceilings which may be cumulated for a maximum of three years. The calculation method is therefore different from the one applied until 2000. A special procedure is applied to the transition between these two methods. Details of those procedures are published in an information sheet made available from divisional secretariats and at the UNIQA office at CERN.

  20. Cluster Lenses

    CERN Document Server

    Kneib, Jean-Paul; 10.1007/s00159-011-0047-3

    2012-01-01

    Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining...

  1. Contact lenses as the best conservative treatment of newly diagnosed keratoconus--epidemiological retrospective study.

    Science.gov (United States)

    Mrazovac, Danijela; Barisić Kutija, Marija; Vidas, Sania; Kuzman, Tomislav; Petricek, Igor; Jandroković, Sonja; Kalauz, Miro; Cerovski, Branimir

    2014-12-01

    Keratoconus is a progressive, non-inflammatory corneal ectasia characterized by thinning and weakening of the corneal stroma which results in its' protrusion. The onset is during puberty and progresses until the fourth decade of life. In earlier stages, good visual acuity can be provided with spectacles. With progression, contact lenses are considered to be a better therapy. Aim of this study was to determine if there is statistically significant difference between best corrected visual acuity (BCVA) obtained by spectacles and contact lenses in newly diagnosed keratoconus patients, as well as to determine which type of contact lenses provide better BCVA in keratoconus patients. We conducted a 5-year retrospective study of all 2891 patients attending our Contact Lens Department for the first time, searching for patients newly diagnosed with keratoconus. Data were obtained on gender, age, education level, treated eyes, corneal changes, keratoconus severity, BCVA with spectacles, contact lenses and best fitted contact lens type. All patients underwent standard ophthalmic exam, refractometry and keratometry have been done, followed by a spectacles correction and lens fitting. Wilcoxon signed rank test was used for statistical analysis. Results showed that of all 2891 patients examined for the first time, 137 patients (4.74%) have been newly diagnosed with heratoconus, there was male bias (72.26%), mean age 27.7 +/- 9.9 years. Most patients had high school education (51.11%), 3.70% had present corneal changes, 50.37% had mild heratoconus. Majority had keratoconus on both eyes (36.3%) or keratoconus of right eye (26.67%). There was a statistically significant difference (pkeratoconus eyes. We have showed that there is a statistically significant difference in BCVA achieved better with contact lenses than with spectacles. RGP lenses are most frequently used in conservative treatment of heratoconus, but SGP lenses were also shown to be a good option that gives equally

  2. Effects of myopic spectacle correction and radial refractive gradient spectacles on peripheral refraction.

    Science.gov (United States)

    Tabernero, Juan; Vazquez, Daniel; Seidemann, Anne; Uttenweiler, Dietmar; Schaeffel, Frank

    2009-08-01

    The recent observation that central refractive development might be controlled by the refractive errors in the periphery, also in primates, revived the interest in the peripheral optics of the eye. We optimized an eccentric photorefractor to measure the peripheral refractive error in the vertical pupil meridian over the horizontal visual field (from -45 degrees to 45 degrees ), with and without myopic spectacle correction. Furthermore, a newly designed radial refractive gradient lens (RRG lens) that induces increasing myopia in all radial directions from the center was tested. We found that for the geometry of our measurement setup conventional spectacles induced significant relative hyperopia in the periphery, although its magnitude varied greatly among different spectacle designs and subjects. In contrast, the newly designed RRG lens induced relative peripheral myopia. These results are of interest to analyze the effect that different optical corrections might have on the emmetropization process.

  3. The spectacle of silence and stillness

    OpenAIRE

    Main, Lesley

    2010-01-01

    This paper explores the interconnecting themes of ‘silence’ and ‘stillness’ as they relate to notions of ‘spectacle’. The discussion will be illustrated with examples from Doris Humphrey’s choreographic works along side contemporary reference points. The paper considers the meaning/s and occurrence of spectacle and will discuss the implications of definitions such as ‘wonderment’, ‘breathtaking’, ‘mesmerising’ and ‘escapist’ in relation to the viewer’s response. A further premise is that the ...

  4. Contact lenses fitting after intracorneal ring segments implantation in keratoconus

    Directory of Open Access Journals (Sweden)

    Luciane Bugmann Moreira

    2013-08-01

    Full Text Available PURPOSE: Evaluate contact lenses fitting after intracorneal ring implantation for keratoconus, its visual acuity and comfort. METHODS: Retrospective study of patients undergoing contact lenses fitting, after intracorneal ring for keratoconus. The criterion for contact lens fitting was unsatisfactory visual acuity with spectacle correction as referred by the patients. All patients were intolerants to contact lenses prior to intracorneal implantation. Visual acuity analysis was done by conversion of Snellen to logMAR scales. The comfort was evaluated according subjective questioning of good, medium or poor comfort. RESULTS: Nineteen patients were included in the study. Two patients (10.5% did not achieved good comfort with contact lenses and underwent penetrating keratoplasties. All the others 17 patients showed good or medium comfort. Four rigid gas-permeable contact lenses were fitted, one piggyback approach, 3 toric soft contact lenses, 2 soft lenses specially design for keratoconus and 7 disposable soft lenses. The average visual acuity improved from 0.77 ± 0.37 to 0.19 ± 0.13 logMAR units after contact lenses fitting. CONCLUSION: Contact lens fitting after intracorneal ring is possible, provides good comfort, improves visual acuity, and therefore, may postpone the need for penetrating keratoplasty.

  5. School Choice Policies in the Political Spectacle

    Directory of Open Access Journals (Sweden)

    Linda Miller-Kahn

    2001-11-01

    Full Text Available This article presents research on school choice. It takes the case of a school district in Boulder, Colorado, through the decade of the 1990s and shows how interest groups took advantage of federal, state, and district policies meant to promote school choice and molded them into a system of schools that met individualistic interests rather than the common good. Extensive interviewing and analysis of documents and media reports served as sources of evidence. The authors argue that district officials accommodated the demands of elite groups of parents to transform the district. The study is framed by revisionist theories of policy, particularly Murray Edelman's theory of political spectacle wherein real values are allocated to a few groups, the allocation occurring largely out of public scrutiny. For most of the public, however, policies are largely symbolic.

  6. Triphenyl phosphate allergy from spectacle frames

    DEFF Research Database (Denmark)

    Carlsen, Lars; Andersen, Klaus E.; Egsgaard, Helge

    1986-01-01

    A case of triphenyl phosphate allergy from spectacle frames is reported. Patch tests with analytical grade triphenyl phosphate, tri-m-cresyl phosphate, and tri-p-cresyl phosphate in the concentrations 5%, 0.5% and 0.05% pet. showed positive reactions to 0.05% triphenyl phosphate and 0.5% tri......-m-cresyl phosphate, but no reaction to tri-p-cresyl phosphate. Gas chromatography of the tricresyl phosphate 5% pet. patch test material supplied from Trolab showed that it contained a mixture of a wide range of triaryl phosphates, including 0.08% triphenyl phosphate which is above the threshold for detecting...... triphenyl phosphate allergy in our patient....

  7. Gravitational lensing

    CERN Document Server

    Dodelson, Scott

    2017-01-01

    Gravitational lensing is a consequence of general relativity, where the gravitational force due to a massive object bends the paths of light originating from distant objects lying behind it. Using very little general relativity and no higher level mathematics, this text presents the basics of gravitational lensing, focusing on the equations needed to understand the phenomena. It then applies them to a diverse set of topics, including multiply imaged objects, time delays, extrasolar planets, microlensing, cluster masses, galaxy shape measurements, cosmic shear, and lensing of the cosmic microwave background. This approach allows undergraduate students and others to get quickly up to speed on the basics and the important issues. The text will be especially relevant as large surveys such as LSST and Euclid begin to dominate the astronomical landscape. Designed for a one semester course, it is accessible to anyone with two years of undergraduate physics background.

  8. Ophthalmic Lenses

    CERN Document Server

    Bhootra, Ajay Kumar

    2009-01-01

    This book is uniquely meant for the ophthalmologists, optometrists and opticians to help the world see better by excellent vision through the services of technicians and clinical principle based ophthalmology so that the management of ocular problems can be done for a better vision . Informs that a wide range of material and design of ophthalmic lenses with innovative developments is available. This book presents comprehensively rich information about the ophthalmic lenses and their dispensing tips . It will be highly useful mainly for the students of optometry and opticians, ophthalmologists,

  9. Status and trend of spectacled eider population in Alaska, 2006

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — An offshore oil and gas lease sale recently proposed by Mineral Management Service in the Chukchi Sea is adjacent to Spectacled Eider critical habitat in Ledyard...

  10. Spectacles in Children‑ Do's and Don'ts

    African Journals Online (AJOL)

    Unlike adults, there is a huge variability of visual acuity assessment even in a ... The search was done using the words – spectacles, children, glasses, and ... produce accommodative esotropia, strabismic amblyopia, and .... [Last accessed on.

  11. SPECFACE - A Dataset of Human Faces Wearing Spectacles

    OpenAIRE

    2015-01-01

    This paper presents a database of human faces for persons wearing spectacles. The database consists of images of faces having significant variations with respect to illumination, head pose, skin color, facial expressions and sizes, and nature of spectacles. The database contains data of 60 subjects. This database is expected to be a precious resource for the development and evaluation of algorithms for face detection, eye detection, head tracking, eye gaze tracking, etc., for subjects wearing...

  12. Spectacle correction versus no spectacles for prevention of strabismus in hyperopic children.

    Science.gov (United States)

    Jones-Jordan, Lisa; Wang, Xue; Scherer, Roberta W; Mutti, Donald O

    2014-08-18

    Hyperopia (far-sightedness) in infancy requires accommodative effort to bring images into focus. Prolonged accommodative effort has been associated with an increased risk of strabismus (eye misalignment). Strabismus makes it difficult for the eyes to work together and may result in symptoms of asthenopia (eye strain) and intermittent diplopia (double vision), and makes near work tasks difficult to complete. Untreated strabismus may result in the development of amblyopia (lazy eye). The prescription of spectacles to correct hyperopic refractive error is believed to prevent the development of strabismus. To assess the effectiveness of prescription spectacles compared with no intervention for the prevention of strabismus in infants and children with hyperopia. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2014), EMBASE (January 1980 to April 2014), PubMed (1966 to April 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 3 April 2014. We also searched the Science Citation Index database in September 2013. We included randomized controlled trials and quasi-randomized trials investigating the assignment to spectacle intervention or no treatment for children with hyperopia. The definition of hyperopia remains subjective, but we required it to be at least greater than +2.00 diopters (D) of hyperopia. Two review authors independently extracted data using the standard methodologic procedures expected by The Cochrane Collaboration. One review author entered data

  13. Mucocele in a spectacled owl (Pusilatrix perspicillata).

    Science.gov (United States)

    Huynh, Minh; Brandão, João; Sabater, Mikel; Stidworthy, Mark F; Forbes, Neil A

    2014-03-01

    A 6-year-old breeding female spectacled owl (Pusilatrix perspicillata) was presented for a soft, fluid-filled, spherical mass under the neck that had been increasing in size over the previous 3 days. Results of a fine-needle aspirate of the mass showed clear, pale-yellow fluid with a total protein of 12.6 g/L. Cytologic examination revealed erythrocytes, moderate numbers of heterophils, and numerous foamy mononuclear cells against a mucoid background. Macroscopically, the mass appeared to be attached firmly to the esophagus. The mass was excised surgically and submitted for histopathologic examination. The lesion comprised a circumscribed, fibrous-encapsulated multilocular cyst, lined by plump, goblet-type, cuboidal epithelial cells lying in abundant mucinous matrix. Findings were consistent with a mucocele of the esophageal mucosal gland. Excision was considered curative based on follow-up 6 months after initial presentation. To our knowledge, this is the first report of this condition in Strigiformes and indicates that mucocele should be included in the differential diagnosis of cervical masses in birds.

  14. Contact Lenses for Keratoconus- Current Practice

    Science.gov (United States)

    Moschos, Marilita M.; Nitoda, Eirini; Georgoudis, Panagiotis; Balidis, Miltos; Karageorgiadis, Eleftherios; Kozeis, Nikos

    2017-01-01

    Background: Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs). Objective: To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs. Method: Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling. Result: The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis. Conclusion: CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is

  15. Contact Lenses for Keratoconus- Current Practice.

    Science.gov (United States)

    Moschos, Marilita M; Nitoda, Eirini; Georgoudis, Panagiotis; Balidis, Miltos; Karageorgiadis, Eleftherios; Kozeis, Nikos

    2017-01-01

    Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs). To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs. Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling. The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis. CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is based on their special features, the subsequent

  16. Green spaces and spectacles use in schoolchildren in Barcelona.

    Science.gov (United States)

    Dadvand, Payam; Sunyer, Jordi; Alvarez-Pedrerol, Mar; Dalmau-Bueno, Albert; Esnaola, Mikel; Gascon, Mireia; De Castro Pascual, Montserrat; Basagaña, Xavier; Morgan, Ian G; Nieuwenhuijsen, Mark J

    2017-01-01

    Myopia is one of the major causes of low visual acuity during childhood, and hence of the need for spectacles. It is generally more prevalent in urban areas where children are often less exposed to green spaces than in rural areas. This study evaluated the association between exposure to green space and use of spectacles (as a surrogate measure for myopia) in a cohort of 2727 schoolchildren (7-10 years old) recruited from 39 primary schools in Barcelona (2012-2015). We assessed exposure to green spaces by characterizing outdoor surrounding greenness at home and school and during commuting using satellite data on greenness (Normalized Difference Vegetation Index). We also obtained data on the annual average time children spent playing in green spaces through questionnaires. Cross-sectional analyses were conducted based on prevalent cases of spectacles use at baseline data collection campaign and longitudinal analyses based on incident cases of spectacles use during the three-year period between the baseline and last data collection campaigns. An interquartile range (IQR) increase in exposure to green space at home (500m buffer) and school and during commuting was associated with respectively 14% (95% CI: 2%, 26%), 27% (95% CI: 6%, 44%), and 20% (95% CI: 5%, 33%) decrease in spectacles use in cross-sectional analyses. In longitudinal analyses, we observed a reduction of 23% (95% CI: 4%, 39%) and 34% (95% CI: 2%, 55%) associated with an IQR increase in greenness at home and school, respectively. Moreover, an IQR increase in time playing in green spaces was associated with a 28% (95% CI: 7%, 45%) reduction in the risk of spectacles use in the longitudinal analysis. Our observed reduced risk of spectacles use associated with higher contact with green space calls for more refined studies of the association between green spaces and refractive errors of visions.

  17. Morphology of the snake spectacle reflects its evolutionary adaptation and development

    DEFF Research Database (Denmark)

    Da Silva, Mari-Ann Otkjaer; Heegaard, Steffen; Wang, Tobias

    2017-01-01

    Background Covering the eye of all snakes is a transparent integumental structure known as the spectacle. In order to determine variations in spectacle thickness among species, the spectacles of 217 alcohol-preserved museum specimens of 44 species belonging to 14 different families underwent...... found in the Usambara bush viper (Viperidae) with a thickness of 74 ± 9 μm and the absolute thickest spectacle was found in the red-tailed pipe snake (Cylindrophiidae) which had a spectacle thickness of 244 ± 57 μm. Fossorial and aquatic snakes had significantly thicker spectacles than arboreal...... and terrestrial snakes. When spectacle thickness was correlated to eye size (horizontal spectacle diameter), Gray’s earth snake (Uropeltidae) had the lowest ratio (1:7) and the cottonmouth (Viperidae) had the highest ratio (1:65). Multivariable and phylogenetic analyses showed that spectacular thickness could...

  18. Decline of spectacled eiders nesting in western Alaska

    Science.gov (United States)

    Stehn, Robert A.; Dau, Christian P.; Conant, Bruce; Butler, William I.

    1993-01-01

    Spectacled eider (Somateria fischeri) populations in western Alaska are now less than 4% of the numbers estimated in the early 1970s. In 1992, an estimated 1721 nesting pairs remained on the Yukon-Kuskokwim Delta. Causes of this rapid and continuing decline of -14% per year are undocumented. Many aspects of spectacled eider biology remain unknown, including their marine foraging habitats, food items, migratory movements, and population ecology. A review of some biological characteristics and possible threats to the species suggests the importance of quantifying potential impacts from parasites and disease, subsistence harvest, predation during brood rearing, and alteration of Bering Sea food resources. Factors causing the population decline of spectacled eiders must be determined and appropriate actions taken to reverse the trend.

  19. Traffic-related air pollution and spectacles use in schoolchildren.

    Science.gov (United States)

    Dadvand, Payam; Nieuwenhuijsen, Mark J; Basagaña, Xavier; Alvarez-Pedrerol, Mar; Dalmau-Bueno, Albert; Cirach, Marta; Rivas, Ioar; Brunekreef, Bert; Querol, Xavier; Morgan, Ian G; Sunyer, Jordi

    2017-01-01

    To investigate the association between exposure to traffic-related air pollution and use of spectacles (as a surrogate measure for myopia) in schoolchildren. We analyzed the impact of exposure to NO2 and PM2.5 light absorbance at home (predicted by land-use regression models) and exposure to NO2 and black carbon (BC) at school (measured by monitoring campaigns) on the use of spectacles in a cohort of 2727 schoolchildren (7-10 years old) in Barcelona (2012-2015). We conducted cross-sectional analyses based on lifelong exposure to air pollution and prevalent cases of spectacles at baseline data collection campaign as well as longitudinal analyses based on incident cases of spectacles use and exposure to air pollution during the three-year period between the baseline and last data collection campaigns. Logistic regression models were developed to quantify the association between spectacles use and each of air pollutants adjusted for relevant covariates. An interquartile range increase in exposure to NO2 and PM2.5 absorbance at home was respectively associated with odds ratios (95% confidence intervals (CIs)) for spectacles use of 1.16 (1.03, 1.29) and 1.13 (0.99, 1.28) in cross-sectional analyses and 1.15 (1.00, 1.33) and 1.23 (1.03, 1.46) in longitudinal analyses. Similarly, odds ratio (95% CIs) of spectacles use associated with an interquartile range increase in exposures to NO2 and black carbon at school was respectively 1.32 (1.09, 1.59) and 1.13 (0.97, 1.32) in cross-sectional analyses and 1.12 (0.84, 1.50) and 1.27 (1.03, 1.56) in longitudinal analyses. These findings were robust to a range of sensitivity analyses that we conducted. We observed increased risk of spectacles use associated with exposure to traffic-related air pollution. These findings require further confirmation by future studies applying more refined outcome measures such as quantified visual acuity and separating different types of refractive errors.

  20. Traffic-related air pollution and spectacles use in schoolchildren

    Science.gov (United States)

    Nieuwenhuijsen, Mark J.; Basagaña, Xavier; Alvarez-Pedrerol, Mar; Dalmau-Bueno, Albert; Cirach, Marta; Rivas, Ioar; Brunekreef, Bert; Querol, Xavier; Morgan, Ian G.; Sunyer, Jordi

    2017-01-01

    Purpose To investigate the association between exposure to traffic-related air pollution and use of spectacles (as a surrogate measure for myopia) in schoolchildren. Methods We analyzed the impact of exposure to NO2 and PM2.5 light absorbance at home (predicted by land-use regression models) and exposure to NO2 and black carbon (BC) at school (measured by monitoring campaigns) on the use of spectacles in a cohort of 2727 schoolchildren (7–10 years old) in Barcelona (2012–2015). We conducted cross-sectional analyses based on lifelong exposure to air pollution and prevalent cases of spectacles at baseline data collection campaign as well as longitudinal analyses based on incident cases of spectacles use and exposure to air pollution during the three-year period between the baseline and last data collection campaigns. Logistic regression models were developed to quantify the association between spectacles use and each of air pollutants adjusted for relevant covariates. Results An interquartile range increase in exposure to NO2 and PM2.5 absorbance at home was respectively associated with odds ratios (95% confidence intervals (CIs)) for spectacles use of 1.16 (1.03, 1.29) and 1.13 (0.99, 1.28) in cross-sectional analyses and 1.15 (1.00, 1.33) and 1.23 (1.03, 1.46) in longitudinal analyses. Similarly, odds ratio (95% CIs) of spectacles use associated with an interquartile range increase in exposures to NO2 and black carbon at school was respectively 1.32 (1.09, 1.59) and 1.13 (0.97, 1.32) in cross-sectional analyses and 1.12 (0.84, 1.50) and 1.27 (1.03, 1.56) in longitudinal analyses. These findings were robust to a range of sensitivity analyses that we conducted. Conclusion We observed increased risk of spectacles use associated with exposure to traffic-related air pollution. These findings require further confirmation by future studies applying more refined outcome measures such as quantified visual acuity and separating different types of refractive errors. PMID

  1. The spectacle of the ball python (Python regius)

    DEFF Research Database (Denmark)

    Da Silva, Mari-Ann Otkjær; Heegaard, Steffen; Wang, Tobias

    2014-01-01

    A detailed morphological description of the spectacle of the ball python (Python regius) is provided. The eyes of 21 snakes were examined by light microscopy and/or transmission electron microscopy. Additionally, eyes of nine live snakes were examined using optical coherence tomography (OCT...

  2. Spectral transmittance of the spectacle scale of snakes and geckos

    NARCIS (Netherlands)

    Doorn, van K.; Sivak, J.G.

    2015-01-01

    The spectral transmittance of the optical media of the eye plays a substantial role in tuning the spectrum of light available for capture by the retina. Certain squamate reptiles, including snakes and most geckos, shield their eyes beneath a layer of transparent, cornified skin called the ‘spectacle

  3. 21 CFR 886.5844 - Prescription spectacle lens.

    Science.gov (United States)

    2010-04-01

    ... for the patient. The device may be modified to protect the eyes from bright sunlight (i.e...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5844 Prescription spectacle lens. (a... photosensitized. (b) Classification. Class I (general controls). The device is exempt from the...

  4. Contact lenses in pediatrics study in Singapore.

    Science.gov (United States)

    Li, Lim; Moody, Kurt; Tan, Donald T H; Yew, Khoo Chong; Ming, Por Yong; Long, Quah Boon

    2009-07-01

    Previous studies in the United States have evaluated the benefits of soft contact lenses (CLs) in 8- to 12-year-old children and 13- to 17-year-old teens. This study was undertaken in Singapore and evaluated the safety, efficacy, and physiologic performance of daily disposable soft lenses in a population of children. In this open-label, bilateral, 3-month dispensing study, 59 children (8-11 years) were fit with etafilcon A spherical or toric daily disposable lenses (1-DAY ACUVUE or 1-DAY ACUVUE for ASTIGMATISM, Vistakon, Jacksonville, FL). All subjects were neophytes requiring visual correction in both eyes. The refractive inclusion criteria were plano to -9.00 diopter (D) with astigmatism of < or =2.00DC in both eyes, or hyperopia of +0.50 to +6.00D with astigmatism of 0.75D or less. The subjects underwent follow-up evaluations, which included a questionnaire for parents and subjects, at 1 week, 1 month, and 3 months. Of the 59 subjects enrolled, 53 (90%) completed the study successfully. Six subjects were discontinued because of lens handling difficulties (four), unacceptable lens fit (one), and an adverse event (one). Adverse events were reported in three subjects, including the discontinuation, and in each case were due to a chalazion. Overall vision quality, overall comfort, and end-of-day comfort were graded significantly better at each of the follow-up visits compared with baseline with spectacles (P< or =0.0001). Both handling and reported symptoms improved during the course of the study. The questionnaire results indicated that most of both parents and subjects preferred CLs to spectacles across a wide variety of aspects including vision, comfort, handling, and appearance. Significantly, more limbal and bulbar hyperemia was noted at follow-up visits than at baseline (P=0.0001); however, no instances of hyperemia greater than grade 2 were noted at any visit. Significantly, more corneal staining was also noted at the 1- and 3-month follow-up visits than at

  5. The Glenn A. Fry award lecture 2013: blurred vision, spectacle correction, and falls in older adults.

    Science.gov (United States)

    Elliott, David B

    2014-06-01

    This article reviews the literature on how blurred vision contributes to falls, gait, and postural control and discusses how these are influenced by spectacle correction. Falls are common and represent a very serious health risk for older people. They are not random events as studies have shown that falls are linked to a range of intrinsic and extrinsic risk factors. Vision provides a significant input to postural control in addition to providing information about the size and position of hazards and obstacles in the travel pathway and allows us to safely negotiate steps and stairs. Many studies have shown that reduced vision is a significant risk factor for falls. However, randomized controlled trials of optometric interventions and cataract surgery have not shown the expected reduction in falls rate, which may be due to magnification changes (and thus vestibulo-ocular reflex gain) in those participants who have large changes in refractive correction. Epidemiological studies have also shown that progressive addition lens and bifocal wearers are twice as likely to fall as non-multifocal wearers, laboratory-based studies have shown safer adaptive gait with single-vision glasses than progressive addition lenses or bifocals, and a randomized controlled trial has shown that an additional pair of distance vision single-vision glasses for outdoor use can reduce falls rate. Clinical recommendations to help optometrists prevent their frail, older patients from falling are suggested.

  6. Types of Contact Lenses

    Science.gov (United States)

    ... back to top ] Rigid Gas Permeable (RGP) Contact Lenses Rigid gas permeable contact lenses (RGPs) are more durable ... Ortho-K) Orthokeratology, or Ortho-K, is a lens fitting procedure that uses specially designed rigid gas permeable (RGP) contact lenses to change the ...

  7. 军事飞行人员佩戴视力矫正镜研究进展%Research progress on military flying personnel wearing corrective spectacles

    Institute of Scientific and Technical Information of China (English)

    王善祥; 强东昌; 张雁歌

    2010-01-01

    目的 综述军事飞行人员佩戴视力矫正镜飞行的研究进展.资料来源与选择该领域的相关研究论文和综述.资料引用国内外公开发表的文献24篇.资料综合综合分析高空低气压、加速度、缺氧、干燥及弹射跳伞等军事航空环境因素对佩戴视力矫正镜的影响,和视力矫正镜在军事航空中的应用.结论 军事飞行人员可以根据不同的机种、职务、任务佩戴不同的视力矫正镜,我军需要尽快开展军事飞行人员佩戴视力矫正镜方面的研究.%Objective To review the research progress on the practice of wearing corrective spectacles or contact lenses in flying personnel.Literature resource and selection Research papers and reviews in this field.Literature quotation Twenty-four published papers and reviews were cited.Literature synthesis The influences on the military flying personnel with corrective spectacles or contact lenses in aviation environment (atmospheric pressure, acceleration, hypoxia,humidity, ejection, etc.) were analyzed and the application of contact lenses in military aviation medicine was evaluated.Conclusion Military aviator wearing corrective spectacles or contact lenses has a quite long history in western countries and it applies according to aircraft type, flying roles and duty.It is acceptable by flying personnel and enables them with ameliorative visual ability in aviation environment.It is suggested to expand corresponding research and practice in China for dealing with the possible decline of flying personnel's diopter.

  8. Morphology of the snake spectacle reflects its evolutionary adaptation and development

    DEFF Research Database (Denmark)

    Da Silva, Mari-Ann Otkjaer; Heegaard, Steffen; Wang, Tobias

    2017-01-01

    optical coherence tomography (OCT) to measure spectacular thickness. Multivariable analyses were made to determine whether family, activity period (diurnal/nocturnal) and habitat (arboreal/terrestrial/fossorial/aquatic) influenced spectacle thickness. Results The thinnest spectacles in absolute terms were...... and terrestrial snakes. When spectacle thickness was correlated to eye size (horizontal spectacle diameter), Gray’s earth snake (Uropeltidae) had the lowest ratio (1:7) and the cottonmouth (Viperidae) had the highest ratio (1:65). Multivariable and phylogenetic analyses showed that spectacular thickness could...

  9. Mental Health Status of the Keratoconus Patients Visually Corrected with Contact Lens Compared to Spectacles

    Directory of Open Access Journals (Sweden)

    Padmakali Banerjee

    2016-12-01

    Full Text Available 1.1.Aim of the Study:To analyse the mental health status and psychological well being of the keratoconus patients using rigid contact lenses compared to spectacle corrected ones. The objective is to study if the correcting vision with contact lenses impacts the mental health status of the patients suffering from keratoconus. 1.2.Methodology:In the month of January to April, 2015 a cross sectional study was conducted in Ahooja eye hospital, Gurgaon, Haryana, India and Rajan eye care hospital, Tnagar, Chennai, Tamilnadu, India. Thirty two keratoconus patients were enrolled for the study and subjects were asked to the mental health status questionnaire MHI 38 with informed consent. Fifteen were habitual contact lens wearers and seventeen non contact lens wearers who volunteered to participate this study. Study included those contact lens users who wore lenses all waking hours and had been wearing them for atleast one year. All the questions were score coded for entering the data in Microsoft Excel sheet. The status of mental health was based on eight indicises which provided information on mental well being. 1.3.Results:17 males and 15 females participated in this study. The mean age of the participant was 28.03± 5.56 (range 20-39 years. The mean score of keratoconus patients of non contact lens wearer and contact lens wearer in Anxiety was 32.84 ± 2.99 &18.79 ± 3.67, Depression 13.34 ± 4.08 & 7.71 ± 2.19, Loss of behavioural / Emotion Control 30.29 ± 2.22 & 22.77 ± 6.70, General Positive Affect 49.00 ± 3.86 & 29.73 ± 4.48, Emotion Ties 10.17 ± 1.44 & 5.28 ± 1.71, Life Satisfaction 3.44 ± 0.96 & 4.94 ± 0.73, Psychological Distress 81.28 ± 4.48 & 53.15 ± 9.62, Psychological Well Being 41.15 ± 4.75 & 69.08 ± 5.26, Mental Health Index 119.81 ± 5.53 & 185.82 ± 11.03 respectively. Our results show that P value is <0.05 is statistically significant in all subscales and on the global scale variable of MHI 38. It suggests those who wear

  10. Myopia Control with Bifocal Contact Lenses: A Randomized Clinical Trial.

    Science.gov (United States)

    Aller, Thomas A; Liu, Maria; Wildsoet, Christine F

    2016-04-01

    Most studies have reported only minimal reductions in myopia progression with bifocal or progressive multifocal spectacles, although somewhat larger, although mostly still clinically insignificant, effects have been reported in children with nearpoint esophoria and/or accommodative dysfunctions. The CONTROL study was a 1-year, prospective, randomized, clinical trial of bifocal contact lenses for control of myopia in children with eso fixation disparities at near. Eighty-six myopic subjects, aged 8 to 18 years, were enrolled in the study after passing the screening examination. Of these, 79 completed lens assignment and 78 completed the study. The mean refractive error of these 79 subjects was -2.69 ± 1.40D (SD), and all had progressed by -0.50D or more since their last examination. All subjects also had eso fixation disparity at near. Subjects were randomly assigned to wear either Vistakon Acuvue 2 (single-vision soft contact lenses [SVSCLs]) or Vistakon Acuvue Bifocal (bifocal soft contact lenses [BFSCLs]). Bifocal adds were selected to neutralize the associated phoria. Treatment outcomes included cycloplegic autorefraction and axial length, assessed in terms of changes after 6 and 12 months of treatment from pretreatment baseline values. The BFSCLs significantly slowed myopia progression, with statistically significant differences between the treatment groups after 6 months. After 12 months of treatment, the SVSCL group had progressed by -0.79 ± 0.43D compared with -0.22 ± 0.34D for the BFSCL group (cycloplegic objective spherical equivalent, average of two eyes). Corresponding axial length changes were 0.24 ± 0.17 mm and 0.05 ± 0.14 mm, respectively. All of these differences were found to be statistically significant (unpaired t-tests, p 70%) compared with most published results with multifocal spectacles. Further studies are warranted to identify the critical factors and mechanisms underlying this myopia control effect.

  11. Stravinsky : figures clownesques du spectacle dansé

    OpenAIRE

    Frey, Leonard H.

    2013-01-01

    L’origine du mot clown remonte au vieux Scandinave klunni (lourdaud / benêt). Comme nous avons pu en juger au cours de ces rencontres, la sémantique historique du terme a connu de nombreuses variations, a été, au fil du temps, soumise aux fluctuations plus ou moins heureuses imposées par le théâtre. Dans cette étude, je me propose d’étudier l’iconographie de la représentation du clown à travers l’une des variantes du spectacle, la danse, le ballet et les musiques d’Igor Stravinsky. Au cours d...

  12. Media's Impact on Educational Policies and Practices: Political Spectacle and Social Control

    Science.gov (United States)

    Anderson, Gary L.

    2007-01-01

    To understand the role of the media in schooling and school reform, it is necessary to examine how the media collude in the construction of the political spectacle, which Edelman (1988) called a meaning machine of alternative realities. The media uses spectacle to generate points of view, perceptions, anxieties, aspirations, and strategies to…

  13. Narrative and Spectacle in the Hollywood Musical: Contrasting the Choreography of Busby Berkeley and Gene Kelly

    Science.gov (United States)

    Pattullo, Lauren

    2007-01-01

    This paper examines the relationship between narrative and spectacle in the Hollywood musical, with reference to the work of Busby Berkeley and Gene Kelly. It discusses Busby Berkeley's "backstage" musicals in terms of his "aggregate" approach to dealing with the narrative/spectacle relationship, and considers the effect of the backstage musical's…

  14. Long-term evaluation of eccentric viewing spectacles in patients with bilateral central scotomas.

    NARCIS (Netherlands)

    Verezen, C.A.; Meulendijks, C.F.M.; Hoyng, C.B.; Klevering, B.J.

    2006-01-01

    PURPOSE: Yoked prism spectacles (eccentric viewing spectacles [EVS]) facilitate eccentric viewing in patients with bilateral central scotomas. This study was conducted to evaluate the long-term success and patient satisfaction of this type of low-vision aid. METHODS. In this retrospective cross-sect

  15. Antifouling leaching technique for optical lenses

    Science.gov (United States)

    Strahle, William J.; Perez, C. L.; Martini, Marinna A.

    1994-01-01

    The effectiveness of optical lenses deployed in water less than 100 m deep is significantly reduced by biofouling caused by the settlement of macrofauna, such as barnacles, hydroids, and tunicates. However, machineable porous plastic rings can be used to dispense antifoulant into the water in front of the lens to retard macrofaunal growth without obstructing the light path. Unlike coatings which can degrade the optical performance, antifouling rings do not interfere with the instrument optics. The authors have designed plastic, reusable cup-like antifouling rings to slip over the optical lenses of a transmissometer. These rings have been used for several deployments on shallow moorings in Massachusetts Bay, MA and have increased the time before fouling degrades optical characteristics

  16. Development and application of spectacles frame parameter measurement apparatus

    Institute of Scientific and Technical Information of China (English)

    Guo Qing; Gary Ming Guo; Hu Hongzhi; Hu Jinquan

    2007-01-01

    The measurement of the spectacles frame parameters has substantial effects on both the production and export of spectacles products. In fact, this measurement is the measurement of related three-dimensional trajectory.The working principles of the measurement apparatus developed based on capacitive grating technology are introduced in this paper. Capacitive grating technology is a precision length measurement method. Its advantages are small volume, low price, low production cost, and easy to obtain precise readings of the measured data. The measurement apparatus is composed of one industrial control computer, two microcontrollers and corresponding circuits. The system stability is guaranteed during the design of the circuit with the practical situation of its industry application taken into account. The software is divided into lower layer and upper layer. Each layer has different emphasis. The causes of system errors and the method of error elimination are also analyzed. The analysis of the data obtained from experiments and the operating results of prototype apparatus both indicate that the proposed measurement apparatus has achieved outstanding competitive technical level of same kind products in international market and thus has ideal implications for mass production.

  17. A bayesian approach to classification criteria for spectacled eiders

    Science.gov (United States)

    Taylor, B.L.; Wade, P.R.; Stehn, R.A.; Cochrane, J.F.

    1996-01-01

    To facilitate decisions to classify species according to risk of extinction, we used Bayesian methods to analyze trend data for the Spectacled Eider, an arctic sea duck. Trend data from three independent surveys of the Yukon-Kuskokwim Delta were analyzed individually and in combination to yield posterior distributions for population growth rates. We used classification criteria developed by the recovery team for Spectacled Eiders that seek to equalize errors of under- or overprotecting the species. We conducted both a Bayesian decision analysis and a frequentist (classical statistical inference) decision analysis. Bayesian decision analyses are computationally easier, yield basically the same results, and yield results that are easier to explain to nonscientists. With the exception of the aerial survey analysis of the 10 most recent years, both Bayesian and frequentist methods indicated that an endangered classification is warranted. The discrepancy between surveys warrants further research. Although the trend data are abundance indices, we used a preliminary estimate of absolute abundance to demonstrate how to calculate extinction distributions using the joint probability distributions for population growth rate and variance in growth rate generated by the Bayesian analysis. Recent apparent increases in abundance highlight the need for models that apply to declining and then recovering species.

  18. Longitudinal study on visual outcome and spectacle use after intracapsular cataract extraction in Northern India

    Directory of Open Access Journals (Sweden)

    Sharma Namrata

    2003-07-01

    Full Text Available Abstract Purpose More than 3 million cataract extractions are undertaken in India annually. Almost 60% of these operations are intracapsular Cataract Extractions. The subsequent optical correction is provided by aphakic spectacles. The aim of this study is to assess visual outcome and perceived benefits of post-operative use of aphakic spectacles. Methods One hundred and sixty-seven persons who had undergone intracapsular cataract extraction and had been given best corrected aphakic spectacles were evaluated one year following prescription of the best corrected aphakic spectacles. Out of these, 82.6% were re-examined in this interview-based longitudinal study. Results The mean age of the male participants was 65.95 years and that of females was 71.26 years. 81.2% of the participants were using the provided spectacles. There was no significant association between the spectacle use and gender of the participant. The commonest reason stated by the respondents, for the non-use of the spectacles was 'poor vision'. 61.7% of the current users of provided spectacles had a visual acuity of 6/18 or better. 91.1% of the current users were very satisfied with the spectacles. All the current users could now manage personal activities and the spectacles had facilitated independent mobility. There was no difference in the level of satisfaction between mono-aphakics and bi-aphakics. Among the satisfied users, the modal spherical power was +10 D followed by + 11 D. About one-third of these required a cylindrical correction. Conclusion Following intracapsular cataract extraction, provision of the best correction after cataract surgery is desirable to obtain an optimal visual outcome.

  19. One Episode, Two Lenses

    Science.gov (United States)

    Drijvers, Paul; Godino, Juan D.; Font, Vicenc; Trouche, Luc

    2013-01-01

    A deep understanding of students' learning processes is one of the core challenges of research in mathematics education. To achieve this, different theoretical lenses are available. The question is how these different lenses compare and contrast, and how they can be coordinated and combined to provide a more comprehensive view on the topic of…

  20. On conformal lenses

    CERN Document Server

    Chen, Huanyang; Li, Hui

    2011-01-01

    Plane mirror can make one object into two for observers on the object's side. Yet, there seems no way to achieve the same effect for observers from all directions. In this letter, we will design a new class of gradient index lenses from multivalued optical conformal mapping. We shall call them the conformal lenses. Such lenses can transform one source into two (or even many) omnidirectionally. Like the overlapped illusion optics does, they can even transform multiple sources into one. Rather than using negative index materials, implementation here only needs isotropic positive index materials like other gradient index lenses. One obvious drawback however, is that they have singular permittivity values which restrict them to functioning at one single frequency. This however, needs not be the case when applying transmutation methods, which enable the lenses to work in a broadband frequency range.

  1. Comparison of visual performance of multifocal intraocular lenses with same material monofocal intraocular lenses.

    Directory of Open Access Journals (Sweden)

    Tomofusa Yamauchi

    Full Text Available PURPOSE: To compare the visual performance of multifocal intraocular lenses (IOLs and monofocal IOLs made of the same material. METHODS: The subjects included patients implanted with either Tecnis® monofocal IOLs (ZA9003 or ZCB00 or Tecnis® multifocal IOLs (ZMA00 or ZMB00 bilaterally. We conducted a retrospective study comparing the two types of IOLs. The multifocal group included 46 patients who were implanted with Tecnis® multifocal IOLs bilaterally. The monofocal group was an age- and sex-matched control group, and included 85 patients who were implanted with Tecnis® monofocal IOLs bilaterally. Lens opacity grading, the radius of corneal curvature, corneal astigmatism, axial length and the refractive status were measured preoperatively. Pupil size, ocular aberrometry, distance, intermediate and near visual acuity, contrast sensitivity with and without glare and the responses to a quality-of-vision questionnaire were evaluated pre- and postoperatively. RESULTS: The uncorrected near visual acuity was significantly better in the multifocal group, whereas both the corrected intermediate and near visual acuity were better in the monofocal group. Contrast sensitivity (with and without glare was significantly better in the monofocal group. The rate of spectacle dependency was significantly lower in the multifocal group. There were no significant differences between the two groups regarding most items of the postoperative quality-of-vision questionnaire (VFQ-25, with the exception that the patients in the monofocal group reported fewer problems with nighttime driving. CONCLUSIONS: The multifocal IOLs used in this study reduced spectacle dependency more so than monofocal IOLs and did not compromise the subjective visual function, with the exception of nighttime driving.

  2. The spectacle of the ball python (Python regius): a morphological description.

    Science.gov (United States)

    Da Silva, Mari-Ann O; Heegaard, Steffen; Wang, Tobias; Nyengaard, Jens R; Bertelsen, Mads F

    2014-05-01

    A detailed morphological description of the spectacle of the ball python (Python regius) is provided. The eyes of 21 snakes were examined by light microscopy and/or transmission electron microscopy. Additionally, eyes of nine live snakes were examined using optical coherence tomography (OCT) and Scheimpflug scanning (Pentacam). The spectacle consists of three layers: outer epithelium, stroma and inner epithelium. The outer epithelium is made up of flat basal cells overlaid by keratin, the stroma consists of organized layers of collagen fibrils with interweaving nerve fibers and blood vessels, and the inner epithelium holds squamous cells containing vesicles and microvilli. At the rim of the spectacle, there is a transition zone, where the spectacle merges with the epidermis and dermis of the periocular scales. This zone is characterized by a greater height of the basal cells of the outer epithelium and a less orderly organization of the stroma compared with the spectacle proper. The thickness of the spectacle was uniform throughout. It averaged 96 ± 10 µm in histological specimens and 108 ± 13 µm using OCT. The subspectacular space was extremely narrow in the live snakes; however, the space was visible at the periphery of the spectacle with OCT.

  3. Severe weather as a spectacle: the Meteo-Show

    Directory of Open Access Journals (Sweden)

    I. Orbe

    2017-06-01

    Full Text Available In this work we focus on perhaps one of the worst journalist practice when dealing with severe weather, the Meteo-Show or the extended practice, especially in TV, for using weather and meteorology for spectacle. Journalism today has found weather information in a real goldmine in terms of audience due to the growing public interest in this matter. However, as it happens with other content, sensationalism and exaggeration have also reached weather information, primarily when episodes of adverse nature (snow, heavy rain, floods, etc. are addressed. In this paper we look to identify the worst practices in weather communication through analysis of examples from real journalist work. We present some keys to understand this trend, highlighting the ingredients that are present in the worst Meteo-show.

  4. [The problem of amblyopia in subluxated lenses (author's transl)].

    Science.gov (United States)

    Schulz, E

    1980-01-01

    A re-evaluation of the incidence and development of amblyopia was carried out in 27 patients with a history of lens subluxation at pre-school age. Due to insufficiently accurate histories and the heterogeneous composition of the material it is impossible to make any valid statement regarding the critical phase of development of deprivation amblyopia. However, it appears that "form-deprivation" amblyopia may regress spontaneously up to early school age following hygienization of the optic media and if optimal spectacles or contact lenses are worn. In individual cases it has been shown that unilateral amblyopias can and should be treated (pleoptics) following hygienization of the optic media. Therefore, early surgical treatment should be considered in such cases, above all in view of the fact that complications are rare.

  5. Toric Intraocular Lenses in the Correction of Astigmatism During Cataract Surgery

    DEFF Research Database (Denmark)

    Kessel, Line; Andresen, Jens; Tendal, Britta

    2016-01-01

    TOPIC: We performed a systematic review and meta-analysis to evaluate the benefit and harms associated with implantation of toric intraocular lenses (IOLs) during cataract surgery. Outcomes were postoperative uncorrected distance visual acuity (UCDVA) and distance spectacle independence. Harms were...... literature search in the Embase, PubMed, and CENTRAL databases within the Cochrane Library. We included randomized clinical trials (RCTs) if they compared toric with non-toric IOL implantation (± relaxing incision) in patients with regular corneal astigmatism and age-related cataracts. We assessed the risk...

  6. Gravitational lensing of quasars

    CERN Document Server

    Eigenbrod, Alexander

    2013-01-01

    The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher r...

  7. COSMOLOGY WITH GRAVITATIONAL LENSES

    Directory of Open Access Journals (Sweden)

    Emilio E. Falco

    2009-01-01

    Full Text Available Gravitational lenses yield a very high rate of return on observational investment. Given their scarcity, their impact on our knowledge of the universe is very signi cant. In the weak- eld limit, lensing studies are based on well-established physics and thus o er a straightforward approach to pursue many currently pressing problems of astrophysics. Examples of these are the signi cance of dark matter and the density, age and size of the universe. I present recent developments in cosmological applications of gravitational lenses, regarding estimates of the Hubble constant using strong lensing of quasars. I describe our recent measurements of time delays for the images of SDSS J1004+4112, and discuss prospects for the future utilizing synoptic telescopes, planned and under construction.

  8. Monitoring of Nesting Spectacled Eiders on Kigigak Island, Yukon Delta NWR, 2011

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Nesting spectacled eiders were monitored for the 20th consecutive year on Kigigak Island, Alaska in 2011. Clutch size, hatch date, and final nest status were...

  9. Late Winter Population and Distribution of Spectacled Eiders (Somateria fischeri) in the Bering Sea

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We conducted aerial surveys in the northern Bering Sea in late winter 1995, 1996 and 1997 to estimate the population of spectacled eiders (Somateria fischeri)...

  10. Spectacled Eider (Somateria fischeri) Banding Records; Kashunuk River, Alaska, 1992-2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Data set containing body morphometric measurement and location data associated with marked Spectacled Eiders, captured near the Kashunuk River, within the...

  11. Late winter population and distribution of Spectacled Eiders (Somateria fischeri) in the Bering Sea 2009

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Following satellite telemetry and aerial survey work from 1993-1998, all or most of the global population of spectacled eiders (Somateria flscheri) is believed to...

  12. Distribution and abundance of spectacled eiders (Somateria fischeri) Mechigmenskiya Bay, Chukotka, Russia September 1995

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Spectacled eiders (Somateria fischeri) were counted in Mechigmenskiya Bay, Chukotka, Russia in early September, 1995, using a grid-type total coverage aerial survey....

  13. Spectacled eider (Somateria fischeri) nest records Kashunuk River and Kigigak Island, Alaska, 1991-2004

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Data set containing nest records for Spectacled Eiders near the Kashunuk River and on Kigigak Island, within the Yukon-Kuskokwim Delta, Alaska. Nests were visited...

  14. Gravitational Lenses of Wormholes

    CERN Document Server

    Nandi, K K; Zhang, Y Z; Nandi, Kamal Kanti; Zakharov, Alexander V.; Zhang, Yuan-Zhong

    2006-01-01

    Gravitational lensing by traversable Lorentzian wormholes is a new possibility and is analyzed in the strong field limit. Wormhole solutions are considered in the Einstein minimally coupled theory and in the brane world model. The observables in both the theories show significant differences from those in the Schwarzschild black hole lensing. It is shown that the zero mass wormholes act as photon sinks. Some special features of the considered solutions are pointed out.

  15. Effect of telescopic spectacles on head stability in normal and low vision.

    Science.gov (United States)

    Demer, J L; Goldberg, J; Porter, F I

    Telescopic spectacles, highly magnifying visual aids mounted in spectacle frames, markedly alter the visual consequences of head movements. To evaluate the effect of this altered visual feedback on head stability, angular head velocity of normally sighted and low vision subjects was measured in the roll, pitch, and yaw axes. Measurements were made under two postural conditions: (1) quiet standing; and (2) walking in place, as well as three visual conditions: (1) eyes closed; (2) unmagnified vision; and (3) vision with 4 x binocular telescopic spectacles. For normal subjects during quiet standing, both unmagnified vision and vision with telescopic spectacles tended to reduce spontaneous head velocity in all axes as compared to the eyes-closed condition. However, in low vision subjects neither unmagnified vision nor vision with telescopic spectacles produced significant changes in values of head velocity relative to those measured with eyes closed. Spontaneous head velocities for standing low vision subjects tended to be higher than in normal subjects, although not all differences were statistically significant. During walking in place, Fourier analysis demonstrated prominent frequency components related to harmonics of the walking frequency under all viewing conditions. In normal subjects, vision with telescopic spectacles, to a greater degree than unmagnified vision, reduced head velocity during walking in the roll and yaw, but not the pitch, axes. For low vision subjects, significant reductions in head velocity during walking were observed only during vision with telescopic spectacles. These findings indicate that vision reduces angular instability of the head during standing and walking. Magnification produced by telescopic spectacles further improves head stability under some conditions, although the effect of vision is least evident in the pitch axis. The stabilizing effect of vision is reduced in low vision subjects.

  16. Power Profiles of Commercial Multifocal Soft Contact Lenses

    Science.gov (United States)

    Kim, Eon; Bakaraju, Ravi C.; Ehrmann, Klaus

    2017-01-01

    ABSTRACT Purpose To evaluate the optical power profiles of commercially available soft multifocal contact lenses and compare their optical designs. Methods The power profiles of 38 types of multifocal contact lenses—three lenses each—were measured in powers +6D, +3D, +1D, −1D, −3D, and −6D using NIMO TR1504 (Lambda-X, Belgium). All lenses were measured in phosphate buffered saline across 8 mm optic zone diameter. Refractive index of each lens material was measured using CLR 12-70 (Index Instruments, UK), which was used for converting measured power in the medium to in-air radial power profiles. Results Three basic types of power profiles were identified: center-near, center-distance, and concentric-zone ring-type designs. For most of the lens types, the relative plus with respect to prescription power was lower than the corresponding spectacle add. For some lens types, the measured power profiles were shifted by up to 1D across the power range relative to their labeled power. Most of the lenses were designed with noticeable amounts of spherical aberration. The sign and magnitude of spherical aberration can either be power dependent or consistent across the power range. Conclusions Power profiles can vary widely between the different lens types; however, certain similarities were also observed between some of the center-near designs. For the more recently released lens types, there seems to be a trend emerging to reduce the relative plus with respect to prescription power, include negative spherical aberration, and keep the power profiles consistent across the power range. PMID:27748699

  17. Expert System for Determination of Type Lenses Glasses Using Forward Chaining Method

    Directory of Open Access Journals (Sweden)

    Atikah Ari Pramesti

    2016-11-01

    Full Text Available One of the branches of computer science that is widely used by humans to help her work is the establishment of an expert system. In this study we will design an expert system for determining the type of spectacle lenses using a forward chaining method. In forward chaining method, starting with the initial information (early symptoms and moved forward to fit more information to find the information in accordance with the rules of the knowledge base and production, and will be concluded in the form of the type of disorder diagnosis of eye disorders and provide solutions in the form of lenses of eyeglasses. Result from this study is that the match calculation of algorithm of forward chaining method between system and manual calculations produce the same output.

  18. Spectacle of Maps: Cartographic Hopes and Anxieties in the Pamirs

    Directory of Open Access Journals (Sweden)

    Martin Saxer

    2016-12-01

    Full Text Available Over the past 150 years, a great number of cartographic anxieties and hopes have shaped lives and relations in the Pamirs. The Great Game over imperial spheres of influence was followed by Soviet and Chinese anxieties regarding territorial integrity and the loyalty of their borderland populations; since the end of the Cold War, settling the remaining demarcated borders has become a primary concern in Central Asia; meanwhile, mining companies are anxious to claim territories for mineral extraction, and the maps of national parks and nature reserves aim at mitigating ecological anxieties and claim spaces for conservation. The result is a veritable spectacle of maps. Following Rob Kitchin and Martin Dodge (2007, this article argues that maps are “ontogenetic” rather than representational—they foster realities on the ground. Map-making projects derived from cartographic anxieties are embedded in particular visions of the future, and thus they can serve as a vantage point from which to explore the changing modes of outside engagement in the Pamirs.

  19. Polyadic devil's lenses.

    Science.gov (United States)

    Calatayud, Arnau; Monsoriu, Juan A; Mendoza-Yero, Omel; Furlan, Walter D

    2009-12-01

    Devil's lenses (DLs) were recently proposed as a new kind of kinoform lens in which the phase structure is characterized by the "devil's staircase" function. DLs are considered fractal lenses because they are constructed following the geometry of the triadic Cantor set and because they provide self-similar foci along the optical axis. Here, DLs are generalized allowing the inclusion of polyadic Cantor distributions in their design. The lacunarity of the selected polyadic fractal distribution is an additional design parameter. The results are coined polyadic DLs. Construction requirements and interrelations among the different parameters of these new fractal lenses are also presented. It is shown that the lacunarity parameter affects drastically the irradiance profile along the optical axis, appodizing higher-order foci, and these features are proved to improve the behavior of conventional DLs under polychromatic illumination.

  20. Gravitational Lensing & Stellar Dynamics

    CERN Document Server

    Koopmans, L V E

    2005-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-anisotropy degeneracies. Second, observational results are presented from the Lenses Structure & Dynamics (LSD) Survey and the Sloan Lens ACS (SLACS) Survey collaborations to illustrate this new methodology in constraining the dark and stellar density profiles, and mass structure, of early-type galaxies to redshifts of unity.

  1. Use of Contact Lenses in Eyes with Severe Keratoconus: Long-term Results

    Directory of Open Access Journals (Sweden)

    Zerrin Tuncer

    2012-05-01

    Full Text Available Pur po se: To evaluate the long-term results of rigid gas permeable (RGP contact lenses in severe keratoconic eyes. Ma te ri al and Met hod: Severe keratoconic eyes with RGP contact lenses were evaluated retrospectively. Re sults: Long-term follow-up results of RGP contact lenses applied to 59 eyes of 42 patients (25 women, 17 men with a diagnosis of severe keratoconus were analyzed. Follow-up period was 3 to 12 years (mean: 6.57±3.60. The mean age at first exam was 25.88±9.10 years, the mean corneal curve K1 was 6.49±0.40 mm and K2 was 5.91±0.40 mm. Mean visual acuities with spectacles and contact lenses were 0.26±0.10 lines (0.63±0.20 logMAR and 0.66±0.20 lines (0.20±0.10 logMAR, respectively. The difference between both visual acuities was statistically significant (p=0.0001. At the last visit, the mean visual acuity with RGP contact lenses was 0.68±0.20 lines (0.19±0.10 logMAR. There was no statistically significant difference in visual acuity between first and last examinations with contact lenses (p=0.32. During the long-term follow-up period, apical scarring developed in 17 eyes. Only the 2 eyes of one patient needed penetrating keratoplasty after 6 years of RGP contact lens use. Dis cus si on: Use of RGP contact lenses should be considered before penetrating keratoplasty in cases of severe keratoconus. (Turk J Ophthalmol 2012; 42: 202-6

  2. Hematology and serum biochemistry of Indian spectacled cobra (Naja naja) and Indian rat snake (Ptyas mucosa).

    Science.gov (United States)

    Muliya, Sanath Krishna; Bhat, Mudraje Narayana

    2016-08-01

    To study the hematology and serum biochemistry parameters of Indian spectacled cobra (Naja naja) and Indian rat snake (Ptyas mucosa) and to evaluate the differences in the same between captive and wild populations. Animals were categorized into four groups, viz., wild Indian spectacled cobra (n=10), wild Indian rat snakes (n=10), captive Indian spectacled cobra (n=10), and captive Indian rat snake (n=10). The snakes were restrained with restraint tubes, and 2 ml of blood was collected from either heart or ventral coccygeal vein. Hematological examinations were performed manually and serum biochemistry assays were performed on semi-automated clinical chemistry analyzer. The values of total erythrocyte count, packed cell volume, and hemoglobin were slightly low in captive spectacled cobras and captive rat snakes compared to wild ones, whereas total leukocyte count was found to be slightly high in wild spectacled cobras compared to captive ones. All the recorded values of biochemical and electrolyte analytes were found to be well within expected range for snakes except for total protein and chloride levels in both the species which was slightly above the expected range. The hematology and serum biochemistry intervals of the two most common Indian snakes are presented here. The data will be useful in routine health evaluations and aiding in better medical management of the species studied. Since this study is the first to report complete hematologic and blood biochemical ranges for the study species, observations made here can also be used as referral intervals for future use.

  3. Gravitational lensing & stellar dynamics

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Mamon, GA; Combes, F; Deffayet, C; Fort, B

    2006-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-ani

  4. Gravitational lensing & stellar dynamics

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Mamon, GA; Combes, F; Deffayet, C; Fort, B

    2006-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and

  5. Gravitational lensing & stellar dynamics

    NARCIS (Netherlands)

    Koopmans, L. V. E.; Mamon, GA; Combes, F; Deffayet, C; Fort, B

    2006-01-01

    Strong gravitational lensing and stellar dynamics provide two complementary and orthogonal constraints on the density profiles of galaxies. Based on spherically symmetric, scale-free, mass models, it is shown that the combination of both techniques is powerful in breaking the mass-sheet and mass-ani

  6. Personal radon dosimetry from eyeglass lenses.

    Science.gov (United States)

    Fleischer, R L; Meyer, N R; Hadley, S A; MacDonald, J; Cavallo, A

    2001-01-01

    Eyeglass lenses are commonly composed of allyl-diglycol carbonate (CR-39), an alpha-particle detecting plastic, thus making such lenses personal radon dosemeters. Samples of such lenses have been obtained, etched to reveal that radon and radon progeny alpha tracks can be seen in abundance, and sensitivities have been calibrated in radon chambers as a primary calibration, and with a uranium-based source of alpha particles as a convenient secondary standard. With one exception natural, environmental (fossil) track densities ranged from less than 3,000 to nearly 70,000 per cm2 for eyeglasses that had been worn for various times from one to nearly five years. Average radon concentrations to which those wearers were exposed are inferred to be in the range 14 to 130 Bq x m(-3) (0.4 to 3.5 pCi x l(-1)). A protocol for consistent, meaningful readout is derived and used. In the exceptional case the fossil track density was 1,780,000 cm(-2) and the inferred (24 h) average radon concentration was 6500 Bq x m(-3) (175 pCi x l(-1)) for a worker at an inactive uranium mine that is used for therapy.

  7. Spectacled Eider (Somateria fischeri) Capture, Banding, and Mark-Resight Records; Kigigak Island, Yukon-Kuskokwim Delta, Alaska, 1992-2004

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Data set containing body morphometric measurement and location data for captured Spectacled Eiders, and resight data for marked Spectacled Eiders on Kigigak Island,...

  8. Obituary--rigid contact lenses.

    Science.gov (United States)

    Efron, Nathan

    2010-10-01

    Scleral and corneal rigid lenses represented 100 per cent of the contact lens market immediately prior to the invention of soft lenses in the mid-1960s. In the United Kingdom today, rigid lenses comprise 2 per cent of all new lens fits. Low rates of rigid lens fitting are also apparent in 27 other countries which have recently been surveyed. Thus, the 1998 prediction of the author that rigid lenses--also referred to as 'rigid gas permeable' (RGP) lenses or 'gas permeable' (GP) lenses--would be obsolete by the year 2010 has essentially turned out to be correct. In this obituary, the author offers 10 reasons for the demise of rigid lens fitting: initial rigid lens discomfort; intractable rigid lens-induced corneal and lid pathology; extensive soft lens advertising; superior soft lens fitting logistics; lack of rigid lens training opportunities; redundancy of the rigid lens 'problem solver' function; improved soft toric and bifocal/varifocal lenses; limited uptake of orthokeratology; lack of investment in rigid lenses; and the emergence of aberration control soft lenses. Rigid lenses are now being fitted by a minority of practitioners with specialist skills/training. Certainly, rigid lenses can no longer be considered as a mainstream form of contact lens correction. May their dear souls (bulk properties) rest in peace.

  9. A slide rule for calculating the ocular accommodation of an ametrope corrected with a spectacle lens.

    Science.gov (United States)

    Wang, Guang-Ji

    2007-07-01

    A slide rule has been designed to calculate the ocular accommodation of an ametrope corrected with a spectacle lens. The slide rule makes the calculation itself easier to perform than with traditional methods and is easily applicable in a clinical setting. In the slide rule, there are 3 scales indicating the power of the spectacle lens, the viewing distance, and the ocular accommodation. The most accurate accommodative unit was used to design the slide rule. The ocular accommodation is the product of the accommodative unit and the dioptric viewing distance. The calculating results are accurate from +21 diopters to all minus powers of the spectacle lens. In a clinical setting, the patients can be advised how much accommodation they exert before and after the refractive surgeries.

  10. Switchable liquid crystal contact lenses: dynamic vision for the ageing eye

    Science.gov (United States)

    Milton, Harry E.; Gleeson, Helen F.; Morgan, Philip B.; Goodby, John W.; Cowling, Stephen; Clamp, John H.

    2014-02-01

    The inability of the eye to focus on nearby objects, presbyopia, is suffered by ~100% of people over the age of 50. Liquid crystal (LC) spectacle lenses have shown great potential for correcting presbyopia. However, correcting presbyopia in contact lens users has proven elusive and existing commercial options suffer significant compromises in vision and comfort. We describe a novel contact lens that includes a liquid crystal element that offers to correct presbyopia without the compromises associated with other technologies. We fabricated variable focus lenses using a balanced optical system, providing the additional optical power presbyopes require for near vision (typically +1.00 D to +2.00 D). The system uses positive optical power from the two substrates and variable negative optical power from the LC layer to form a balanced optical system which, when unpowered, corrects distance vision. Upon voltage application, the liquid crystal layer decreases in refractive index, resulting in additional optical power in the system, offering correction equivalent to reading glasses. Our new technology is based on a traditional contact lens material which could be placed directly on the eye. The liquid crystal lens employed is well suited to the small optical areas associated with contact lenses. We compare several different LC materials and geometries which are suitable for our application, and discuss the influence of material and geometry on switching times, optical quality and operating voltage. Our contact lenses typically switch +/-2.00D in response to < 10 Vrms with response times of the order of a second.

  11. Comparison of outcomes with multifocal intraocular lenses: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Béatrice Cochener

    2011-01-01

    Full Text Available Béatrice Cochener1, Antoine Lafuma2, Babak Khoshnood2, Laurène Courouve2, Gilles Berdeaux3,41Centre Hospitalier Universitaire Brest, Brest, France; 2Cemka Eval, Bourg la Reine, France; 3Alcon France, Rueil-Malmaison, France; 4Conservatoire National des Arts et Métiers, Paris, FrancePurpose: To compare the clinical outcome of different multifocal intraocular lenses (IOLs based on information reported in the international literature.Methods: All comparative clinical trials that involved implanting at least one multifocal IOL in patients with cataract or presbyopia were extracted from the literature. Clinical outcomes included uncorrected near visual acuity, uncorrected distance visual acuity, visual acuity, spectacle independence, and halos. Random effects meta-analyses were conducted to compare outcomes for the different IOL types.Results: Twenty papers were identified describing 11 monofocal IOLs and 35 multifocal IOLs (19 diffractive, including 12 ReSTOR®, 14 refractive, and two accommodative patient cohorts. Multifocal and monofocal uncorrected distance visual acuity was 0.165 (0.090–0.240 and 0.093 (0.088–0.098, respectively. Compared with monofocal IOLs, multifocal IOLs produced better uncorrected near visual acuity (0.470 [0.322–0.618] versus 0.141 [0.131–0.152]; P < 0.0001, resulting in higher spectacle independence (incidence rate ratio [IRR] 3.62 [2.90–4.52]; P < 0.0001. Compared with refractive multifocal IOLs, diffractive multifocal IOLs produced a similar uncorrected distance visual acuity (0.105 [0.098–0.111] versus 0.085 [0.029–0.140]; P ≤ 0.78, not significant and better uncorrected near visual acuity (0.217 [0.118–0.317] versus 0.082 [0.067–0.098]; P < 0.0001 resulting in higher spectacle independence (IRR 1.75 [1.24–2.48]; P < 0.001. Compared with other multifocal IOLs, ReSTOR produced a better uncorrected distance visual acuity (0.067 [0.059–0.076] versus 0.093 [0.088–0.098]; P < 0.0001 and better

  12. From the society of the spectacle to the society of the machinery: mutations in popular culture 1960s-2000s

    NARCIS (Netherlands)

    Teurlings, J.

    2013-01-01

    When Guy Debord wrote The Society of the Spectacle in 1967, he was criticizing a society that was saturated by mass media and the endless stream of representations they crank out. This article argues that the society of the spectacle as described by Debord has mutated into a new form, best described

  13. Research of spectacle frame measurement system based on structured light method

    Science.gov (United States)

    Guan, Dong; Chen, Xiaodong; Zhang, Xiuda; Yan, Huimin

    2016-10-01

    Automatic eyeglass lens edging system is now widely used to automatically cut and polish the uncut lens based on the spectacle frame shape data which is obtained from the spectacle frame measuring machine installed on the system. The conventional approach to acquire the frame shape data works in the contact scanning mode with a probe tracing around the groove contour of the spectacle frame which requires a sophisticated mechanical and numerical control system. In this paper, a novel non-contact optical measuring method based on structured light to measure the three dimensional (3D) data of the spectacle frame is proposed. First we focus on the processing approach solving the problem of deterioration of the structured light stripes caused by intense specular reflection on the frame surface. The techniques of bright-dark bi-level fringe projecting, multiple exposuring and high dynamic range imaging are introduced to obtain a high-quality image of structured light stripes. Then, the Gamma transform and median filtering are applied to enhance image contrast. In order to get rid of background noise from the image and extract the region of interest (ROI), an auxiliary lighting system of special design is utilized to help effectively distinguish between the object and the background. In addition, a morphological method with specific morphological structure-elements is adopted to remove noise between stripes and boundary of the spectacle frame. By further fringe center extraction and depth information acquisition through the method of look-up table, the 3D shape of the spectacle frame is recovered.

  14. Learning unit: Thin lenses

    Science.gov (United States)

    Nita, L.-S.

    2012-04-01

    Learning unit: Thin lenses "Why objects seen through lenses are sometimes upright and sometimes reversed" Nita Laura Simona National College of Arts and Crafts "Constantin Brancusi", Craiova, Romania 1. GEOMETRIC OPTICS. 13 hours Introduction (models, axioms, principles, conventions) 1. Thin lenses (Types of lenses. Defining elements. Path of light rays through lenses. Image formation. Required physical quantities. Lens formulas). 2. Lens systems (Non-collated lenses. Focalless systems). 3. Human eye (Functioning as an optical system. Sight defects and their corrections). 4. Optical instruments (Characteristics exemplified by a magnifying glass. Paths of light rays through a simplified photo camera. Path of light rays through a classical microscope) (Physics curriculum for the IXth grade/ 2011). This scenario exposes a learning unit based on experimental sequences (defining specific competencies), as a succession of lessons started by noticing a problem whose solution assumes the setup of an experiment under laboratory conditions. Progressive learning of theme objectives are realised with sequential experimental steps. The central cognitive process is the induction or the generalization (development of new knowledge based on observation of examples or counterexamples of the concept to be learnt). Pupil interest in theme objectives is triggered by problem-situations, for example: "In order to better see small objects I need a magnifying glass. But when using a magnifier, small object images are sometimes seen upright and sometimes seen reversed!" Along the way, pupils' reasoning will converge to the idea: "The image of an object through a lens depends on the relative distances among object, lens, and observer". Associated learning model: EXPERIMENT Specific competencies: derived from the experiment model, in agreement with the following learning unit steps I. Evoking - Anticipation: Size of the problem, formulation of hypotheses and planning of experiment. II

  15. Factors associated with spectacle-wear compliance among school children of 7-15 years in South India

    Directory of Open Access Journals (Sweden)

    MB Pavithra

    2014-04-01

    Full Text Available Background: Easily correctable refractive errors are the commonest cause of visual impairment in school children in India. Children who need but cannot afford spectacle correction are high in our country. Important factor for the success of the corrective services is compliance to spectacle wear. Objective: To assess the spectacle wear compliance among school children who were provided spectacle free of cost. To study the determinants of spectacle acceptance and reasons for non compliance. Materials and Methods: All (1378 government school children of 7-15 years age group in both rural and urban field practice areas of a medical college in Bangalore were screened and students with refractive error were provided spectacles free of cost. An unannounced follow up was done after 3 months to assess compliance. Data was analyzed to determine the factors associated with spectacle wear compliance. Results: Among 36 boys and 47 girls who received spectacles free of cost, 31 were from rural and 52 from urban schools. 48(57.8% children were actually wearing the spectacles at the time of follow up. 42(87.5% compliant children reported improvement of performance in school related activities. Compliance was better in younger children and those from urban schools. Children of father with lower level of education and with power -0.5D were more likely to be non compliant. Conclusion: To achieve the goal of vision 2020 timely detection of refractive errors should be followed by cost effective intervention. The barriers to spectacle acceptance should be studied and addressed.

  16. Plastic Surgery

    Science.gov (United States)

    ... Surgery? A Week of Healthy Breakfasts Shyness Plastic Surgery KidsHealth > For Teens > Plastic Surgery Print A A ... forehead lightened with a laser? What Is Plastic Surgery? Just because the name includes the word "plastic" ...

  17. Pulsar lensing geometry

    CERN Document Server

    Liu, Siqi; Macquart, J-P; Brisken, Walter; Deller, Adam

    2015-01-01

    Our analysis of archival VLBI data of PSR 0834+06 revealed that its scintillation properties can be precisely modelled using the inclined sheet model (Pen & Levin 2014), resulting in two distinct lens planes. These data strongly favour the grazing sheet model over turbulence as the primary source of pulsar scattering. This model can reproduce the parameters of the observed diffractive scintillation with an accuracy at the percent level. Comparison with new VLBI proper motion results in a direct measure of the ionized ISM screen transverse velocity. The results are consistent with ISM velocities local to the PSR 0834+06 sight-line (through the Galaxy). The simple 1D structure of the lenses opens up the possibility of using interstellar lenses as precision probes for pulsar lens mapping, precision transverse motions in the ISM, and new opportunities for removing scattering to improve pulsar timing. We describe the parameters and observables of this double screen system. While relative screen distances can i...

  18. Interactive Learning Media for Lenses and Their Applications Using Macro Visual Basic in Microsoft PowerPoint

    Science.gov (United States)

    Sami Novita, Sari; Nurul Khotimah, Siti; Hidayat, Wahyu

    2016-08-01

    There are two types of lenses are used, namely a convex lens and a concave lens. Microscope is a tool that uses two convex lenses as the eyepiece and objective lens because it can form a magnified image. Instead concave lens is usually used as a spectacle lens for nearsightedness patients because the distance of image formed is closer than the distance of the object. Just like a mirror, the image formation by lenses also can be conveniently determined with ray diagrams. Therefore, this research aims to create a simulation of ray diagrams in the process of image formation by lenses and their applications using Macro Visual Basic in Microsoft PowerPoint. Lenses applications made are the microscope simulation and the combined lenses which consist of a concave-convex lens combined and a convex-concave lens combined. This research begins with the preparation of material on the image formation by lenses and their application. Second, made an appearance on the program which consists of a PowerPoint slide, CommandButton, Textbox, OptionButton, Shape and others then wrote programs in Macro Visual Basic procedure to active the command to do. Input of this simulation can be given in the form of object distance, focal point distance of lens and height of objects. The data will be processed according to commands contained in macros procedure to result image distance, image height, image magnification and the properties of image. In addition to result the data, media can also provide output in the form of ray diagrams simulation on the image formation that can be used to assist students understanding the image formation by lenses.

  19. Comparative morphology of the snake spectacle using light and transmission electron microscopy

    DEFF Research Database (Denmark)

    Da Silva, Mari-Ann O; Bertelsen, Mads F; Wang, Tobias

    2016-01-01

    of three layers. The outer epithelium was made of basal cells with overlaying keratin layers, the stroma comprised layers of organized collagen fibrils, and the inner epithelium was a layer of squamous cells with microvilli. Blood vessels were found in the stroma of all spectacles: in boas and pythons...

  20. Nonconjugate adaptation of human saccades to anisometropic spectacles: Meridian-specificity

    NARCIS (Netherlands)

    H.G. Lemij (Hans); H. Collewijn (Han)

    1992-01-01

    textabstractAbstract Recently it has been demonstrated that saccades become different in size in the two eyes if a subject is adapted to anisometropic spectacles, which provide visual images of different magnitude to the two eyes. These nonconjugate adaptations adequately meet the requirements of th

  1. Bristol Palin: The Pedagogical Media Spectacle of a Sexual Abstinence Ambassador

    Science.gov (United States)

    DaoJensen, Thuy

    2013-01-01

    This paper explores the public political media spectacle of Bristol Palin's teenage pregnancy and her status as a single mother through the lens of a critical feminist discourse analysis. The author explores how cultural anxieties over teenage sexuality and unintended pregnancy in America are constructed when the pregnant teen is the daughter…

  2. The "Spectacle de la Nature" in Eighteenth-Century Spain: From French Households to Spanish Workshops

    Science.gov (United States)

    Serrano, Elena

    2012-01-01

    This paper analyzes the Spanish appropriation of one of the great French eighteenth-century best-sellers, the "Spectacle de la Nature" (1732-1750) by the "abbe" Antoine Noel Pluche. In eight volumes, the "abbe" discussed current issues in natural philosophy, such as Newtonianism, the origin of fossils, artisan…

  3. Bristol Palin: The Pedagogical Media Spectacle of a Sexual Abstinence Ambassador

    Science.gov (United States)

    DaoJensen, Thuy

    2013-01-01

    This paper explores the public political media spectacle of Bristol Palin's teenage pregnancy and her status as a single mother through the lens of a critical feminist discourse analysis. The author explores how cultural anxieties over teenage sexuality and unintended pregnancy in America are constructed when the pregnant teen is the daughter…

  4. 75 FR 17760 - Endangered and Threatened Wildlife and Plants; Spectacled Eider (Somateria fischeri): Initiation...

    Science.gov (United States)

    2010-04-07

    ... is in danger of extinction throughout all or a significant portion of its range; and (C) Threatened... Fish and Wildlife Service Endangered and Threatened Wildlife and Plants; Spectacled Eider (Somateria... or endangered on the List of Endangered and Threatened Wildlife and Plants is accurate. We request...

  5. Media Spectacle, Insurrection and the Crisis of Neoliberalism from the Arab Uprisings to Occupy Everywhere!

    Science.gov (United States)

    Kellner, Douglas

    2013-01-01

    I argue that 2011 witnessed a series of challenges to neoliberalism on a global scale perhaps not seen since the political upheavals of 1968, and that media spectacle provided the form of a series of global insurgences from the North African Arab Uprisings to the Occupy movements. Crises of neoliberalism also generated movements in Italy, Spain,…

  6. The "Spectacle de la Nature" in Eighteenth-Century Spain: From French Households to Spanish Workshops

    Science.gov (United States)

    Serrano, Elena

    2012-01-01

    This paper analyzes the Spanish appropriation of one of the great French eighteenth-century best-sellers, the "Spectacle de la Nature" (1732-1750) by the "abbe" Antoine Noel Pluche. In eight volumes, the "abbe" discussed current issues in natural philosophy, such as Newtonianism, the origin of fossils, artisan…

  7. Efficient Dielectric Metasurface Collimating Lenses for Mid-Infrared Quantum Cascade Lasers

    CERN Document Server

    Arbabi, Amir; Horie, Yu; Bagheri, Mahmood; Faraon, Andrei

    2015-01-01

    Light emitted from single-mode semiconductor lasers generally has large divergence angles, and high numerical aperture lenses are required for beam collimation. Visible and near infrared lasers are collimated using aspheric glass or plastic lenses, yet collimation of mid-infrared quantum cascade lasers typically requires more costly aspheric lenses made of germanium, chalcogenide compounds, or other infrared-transparent materials. Here we report mid-infrared dielectric metasurface flat lenses that efficiently collimate the output beam of single-mode quantum cascade lasers. The metasurface lenses are composed of amorphous silicon posts on a flat sapphire substrate and can be fabricated at low cost using a single step conventional UV binary lithography. Mid-infrared radiation from a 4.8 $\\mu$m distributed-feedback quantum cascade laser is collimated using a polarization insensitive metasurface lens with 0.86 numerical aperture and 79% transmission efficiency. The collimated beam has a half divergence angle of 0...

  8. Additive manufacturing of tunable lenses

    Science.gov (United States)

    Schlichting, Katja; Novak, Tobias; Heinrich, Andreas

    2017-02-01

    Individual additive manufacturing of optical systems based on 3D Printing offers varied possibilities in design and usage. In addition to the additive manufacturing procedure, the usage of tunable lenses allows further advantages for intelligent optical systems. Our goal is to bring the advantages of additive manufacturing together with the huge potential of tunable lenses. We produced tunable lenses as a bundle without any further processing steps, like polishing. The lenses were designed and directly printed with a 3D Printer as a package. The design contains the membrane as an optical part as well as the mechanical parts of the lens, like the attachments for the sleeves which contain the oil. The dynamic optical lenses were filled with an oil. The focal length of the lenses changes due to a change of the radius of curvature. This change is caused by changing the pressure in the inside of the lens. In addition to that, we designed lenses with special structures to obtain different areas with an individual optical power. We want to discuss the huge potential of this technology for several applications. Further, an appropriate controlling system is needed. Wéll show the possibilities to control and regulate the optical power of the lenses. The lenses could be used for illumination tasks, and in the future, for individual measurement tasks. The main advantage is the individuality and the possibility to create an individual design which completely fulfills the requirements for any specific application.

  9. Cross-correlating Planck CMB lensing with SDSS: Lensing-lensing and galaxy-lensing cross-correlations

    CERN Document Server

    Singh, Sukhdeep; Brownstein, Joel R

    2016-01-01

    We present first results from cross-correlating Planck CMB lensing maps with the Sloan Digital Sky Survey (SDSS) galaxy lensing shape catalog and BOSS galaxy catalogs. For galaxy position vs. CMB lensing cross-correlations, we measure the convergence signal around the galaxies in configuration space, using the BOSS LOWZ ($z\\sim0.30$) and CMASS ($z\\sim0.57$) samples. With fixed Planck 2015 cosmology, doing a joint fit with the galaxy clustering measurement, for the LOWZ (CMASS) sample we find a galaxy bias $b_g=1.75\\pm0.04$ ($1.95\\pm 0.02$) and galaxy-matter cross-correlation coefficient $r_{cc}=1.0\\pm0.2$ ($0.8\\pm 0.1$) using $20lensing. Using the same scales and including the galaxy-galaxy lensing measurements, we constrain $\\Omega_m=0.284\\pm0.024$ and relative calibration bias between the CMB lensing and galaxy lensing to be $b_\\gamma=0.82^{+0.15}_{-0.14}$. The combination of galaxy lensing and CMB lensing also allows us to measure the cosmolo...

  10. Modification of depth and distance perception caused by long-term wearing of left-right reversing spectacles.

    Science.gov (United States)

    Ichikawa, Makoto; Kimura, Takahiko; Egusa, Hiroyuki; Nakatsuka, Makiko; Amano, Jun; Ueda, Tomomi; Tashiro, Takara

    2003-01-01

    For 35 to 39 days, four observers wore continuously left-right reversing spectacles which pseudoscopically reverse the order of binocular disparity and direction of convergence. In three tests, we investigated how the visual system copes with the transformation of depth and distance information due to the reversing spectacles. In stereogram observation, after a few days of wearing the spectacles. the observers sometimes perceived a depth order which was opposite to the depth order that they had perceived in the pre-spectacle-wearing period. Monocular depth cues contributed more to depth perception in the spectacle-wearing period than they did in the pre-spectacle-wearing period. While the perceived distance significantly decreased during the spectacle-wearing period, we found no evidence of adaptive change in distance perception. The results indicate that the visual system adapts itself to the transformed situation by not only changing the processing of disparity but also by changing the relative efficiency of each cue in determining apparent depth.

  11. Longitudinal monitoring of sex steroid hormones in excrement of spectacled eiders (Somateria fischeri).

    Science.gov (United States)

    Ellsworth, Abigail; Buck, C Loren; Atkinson, Shannon; Hollmén, Tuula

    2014-03-01

    From the 1970s to the 1990s, the breeding population of spectacled eiders (Somateria fischeri) in western Alaska declined by 96%, which led to the listing of this species as threatened under the Endangered Species Act in 1993. Since then, the population has stabilized, but has not recovered to pre-decline numbers. While little is known about reproductive endocrinology in spectacled eiders, in other avian species, estrogen and testosterone are known to initiate and modulate various reproductive processes including yolk protein synthesis, reproductive behaviors and secondary sex characteristics. Measurement of the metabolites of estrogen and testosterone (EM and TM, respectively) in excrement reflect circulating hormone concentrations and provide a non-invasive method to monitor reproductive physiology. We measured concentrations of excreted EM in captive females and TM in males to (1) determine the efficacy of commercially available radioimmunoassay kits to detect EM and TM, (2) describe annual profiles of EM and TM concentrations, and (3) define the reproductive season of captive spectacled eiders using endocrine status. Excrement samples were collected from captive female and male spectacled eiders three times per week throughout 1 year. Female EM and male TM levels were quantified using radioimmunoassay. Mean female EM profile exhibited values exceeding the threshold for "peak" values (EM>193.3 ng/g) from mid-February to early July, and again in September. Additionally, the highest average concentrations of EM were seen in March, May and September. Elevated TM concentrations occurred in mid March, mid May and late June. These data suggest that levels of excreted sex steroids reflect patterns predicted by breeding landmarks in the annual cycle and will assist in field monitoring and captive breeding programs for spectacled eiders.

  12. Hematology and serum biochemistry of Indian spectacled cobra (Naja naja and Indian rat snake (Ptyas mucosa

    Directory of Open Access Journals (Sweden)

    Sanath Krishna Muliya

    2016-08-01

    Full Text Available Aim: To study the hematology and serum biochemistry parameters of Indian spectacled cobra (Naja naja and Indian rat snake (Ptyas mucosa and to evaluate the differences in the same between captive and wild populations. Materials and Methods: Animals were categorized into four groups, viz., wild Indian spectacled cobra (n=10, wild Indian rat snakes (n=10, captive Indian spectacled cobra (n=10, and captive Indian rat snake (n=10. The snakes were restrained with restraint tubes, and 2 ml of blood was collected from either heart or ventral coccygeal vein. Hematological examinations were performed manually and serum biochemistry assays were performed on semi-automated clinical chemistry analyzer. Results: The values of total erythrocyte count, packed cell volume, and hemoglobin were slightly low in captive spectacled cobras and captive rat snakes compared to wild ones, whereas total leukocyte count was found to be slightly high in wild spectacled cobras compared to captive ones. All the recorded values of biochemical and electrolyte analytes were found to be well within expected range for snakes except for total protein and chloride levels in both the species which was slightly above the expected range. Conclusion: The hematology and serum biochemistry intervals of the two most common Indian snakes are presented here. The data will be useful in routine health evaluations and aiding in better medical management of the species studied. Since this study is the first to report complete hematologic and blood biochemical ranges for the study species, observations made here can also be used as referral intervals for future use.

  13. Hematology and serum biochemistry of Indian spectacled cobra (Naja naja) and Indian rat snake (Ptyas mucosa)

    Science.gov (United States)

    Muliya, Sanath Krishna; Bhat, Mudraje Narayana

    2016-01-01

    Aim: To study the hematology and serum biochemistry parameters of Indian spectacled cobra (Naja naja) and Indian rat snake (Ptyas mucosa) and to evaluate the differences in the same between captive and wild populations. Materials and Methods: Animals were categorized into four groups, viz., wild Indian spectacled cobra (n=10), wild Indian rat snakes (n=10), captive Indian spectacled cobra (n=10), and captive Indian rat snake (n=10). The snakes were restrained with restraint tubes, and 2 ml of blood was collected from either heart or ventral coccygeal vein. Hematological examinations were performed manually and serum biochemistry assays were performed on semi-automated clinical chemistry analyzer. Results: The values of total erythrocyte count, packed cell volume, and hemoglobin were slightly low in captive spectacled cobras and captive rat snakes compared to wild ones, whereas total leukocyte count was found to be slightly high in wild spectacled cobras compared to captive ones. All the recorded values of biochemical and electrolyte analytes were found to be well within expected range for snakes except for total protein and chloride levels in both the species which was slightly above the expected range. Conclusion: The hematology and serum biochemistry intervals of the two most common Indian snakes are presented here. The data will be useful in routine health evaluations and aiding in better medical management of the species studied. Since this study is the first to report complete hematologic and blood biochemical ranges for the study species, observations made here can also be used as referral intervals for future use. PMID:27651683

  14. Roulettes: A weak lensing formalism for strong lensing - I. Overview

    CERN Document Server

    Clarkson, Chris

    2016-01-01

    We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the non-linear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. We show how an image distorted by a generic lens may be constructed as a sum over `roulettes', which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, ...

  15. RHIC electron lenses upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Altinbas, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Binello, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Costanzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, J. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mi, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Pikin, A. I. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Samms, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Shrey, T. C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Tan, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  16. Halo-lensing or Self-lensing? Locating the MACHO Lenses

    Science.gov (United States)

    Nelson, C. A.; Cook, K. H.; Popowski, P.; Drake, A. J.; Marshall, S. L.; Griest, K.; Vandehei, T.; Alcock, C.; Allsman, R. A.; Axelrod, T. S.; Freeman, K. C.; Peterson, B. A.; Alves, D. R.; Becker, A. C.; Stubbs, C. W.; Tomaney, A. B.; Bennett, D. P.; Geha, M.; Lehner, M. J.; Minniti, D.; Pratt, M. R.; Quinn, P. J.; Sutherland, W.; Welch, D.; MACHO Collaboration

    2000-12-01

    There are two principle geometrical arrangements which may explain Large Magellanic Cloud (LMC) microlensing: a) halo-lensing, in which the lensed object is part of the Milky Way galactic halo and b) self-lensing, in which the lensed object is part of the LMC. Self-lensing in turn may be broken into two categories: LMC-LMC self-lensing, in which both the source and the lens reside in the LMC and background self-lensing, in which the lens is a star in the LMC and the source star is drawn from some population behind the LMC. Models suggest the contribution of LMC-LMC self-lensing is small, so the nature of LMC microlensing may be estimated from the location of the microlensing source stars. If the source stars are in the LMC then microlensing is dominated by halo-lensing; conversely if the source stars are located behind the LMC then microlensing is dominated by self-lensing. Since background populations reside behind the LMC, we expect them to be both redder and fainter then the average population of the LMC. We attempt to determine if the MACHO source stars come from such a background population by comparing the HST color-magnitude diagram (CMD) of source stars to the CMD of the average population of the LMC and looking for the effects of extra reddening and extinction. The microlensing source stars are identified by deriving accurate centroids in the ground-based MACHO images using difference image analysis (DIA) and then transforming the DIA coordinates to the HST frame. Preliminary results suggest that halo-lensing accounts for ≳ 40% of the observed microlensing results. Support provided by NASA, DOE, NSF and NPSC.

  17. Magnetic electron lenses

    CERN Document Server

    1982-01-01

    No single volume has been entirely devoted to the properties of magnetic lenses, so far as I am aware, although of course all the numerous textbooks on electron optics devote space to them. The absence of such a volume, bringing together in­ formation about the theory and practical design of these lenses, is surprising, for their introduction some fifty years ago has created an entirely new family of commercial instruments, ranging from the now traditional transmission electron microscope, through the reflection and transmission scanning microscopes, to co­ lumns for micromachining and microlithography, not to mention the host of experi­ mental devices not available commercially. It therefore seemed useful to prepare an account of the various aspects of mag­ netic lens studies. These divide naturally into the five chapters of this book: the theoretical background, in which the optical behaviour is described and formu­ lae given for the various aberration coefficients; numerical methods for calculat­ ing...

  18. Refractive surgery or contact lenses – how and when to decide?

    Directory of Open Access Journals (Sweden)

    Xu K

    2011-11-01

    Full Text Available Kunyong Xu1, Vishal Jhanji2 1Michael G DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada; 2Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong Abstract: Correction of refractive errors can be achieved with spectacles, contact lenses, and refractive surgery. The past decade has seen a surge in the availability of alternatives for patients and surgeons in terms of both surgical and nonsurgical options for the management of refractive errors. Newer generation contact lenses provide enhanced safety and better handling, whereas modern-day refractive surgery presents a plethora of choices based on the clinical characteristics and requirements of patients. We have moved from an era of "one size fits all" to a purely customized way of treating patients with refractive errors. This review presents the background, advantages, and disadvantages of the two most commonly used options for correction of ametropia, ie, contact lenses and refractive surgery. Keywords: laser-assisted in situ keratomileusis, contact lens, patient selection, complications, outcomes

  19. Roulettes: a weak lensing formalism for strong lensing: I. Overview

    Science.gov (United States)

    Clarkson, Chris

    2016-08-01

    We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the nonlinear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. We show how an image distorted by a generic lens may be constructed as a sum over ‘roulettes’, which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, shear and flexion of weak lensing to arbitrary order, and provides a unified bridge between the strong and weak lensing regimes. This overview paper is accompanied by a much more detailed paper II, arXiv:1603.04652.

  20. Subaru Weak Lensing Measurements of Four Strong Lensing Clusters: Are Lensing Clusters Over-Concentrated?

    Energy Technology Data Exchange (ETDEWEB)

    Oguri, Masamune; Hennawi, Joseph F.; Gladders, Michael D.; Dahle, Haakon; Natarajan, Priyamvada; Dalal, Neal; Koester, Benjamin P.; Sharon, Keren; Bayliss, Matthew

    2009-01-29

    We derive radial mass profiles of four strong lensing selected clusters which show prominent giant arcs (Abell 1703, SDSS J1446+3032, SDSS J1531+3414, and SDSS J2111-0115), by combining detailed strong lens modeling with weak lensing shear measured from deep Subaru Suprime-cam images. Weak lensing signals are detected at high significance for all four clusters, whose redshifts range from z = 0.28 to 0.64. We demonstrate that adding strong lensing information with known arc redshifts significantly improves constraints on the mass density profile, compared to those obtained from weak lensing alone. While the mass profiles are well fitted by the universal form predicted in N-body simulations of the {Lambda}-dominated cold dark matter model, all four clusters appear to be slightly more centrally concentrated (the concentration parameters c{sub vir} {approx} 8) than theoretical predictions, even after accounting for the bias toward higher concentrations inherent in lensing selected samples. Our results are consistent with previous studies which similarly detected a concentration excess, and increases the total number of clusters studied with the combined strong and weak lensing technique to ten. Combining our sample with previous work, we find that clusters with larger Einstein radii are more anomalously concentrated. We also present a detailed model of the lensing cluster Abell 1703 with constraints from multiple image families, and find the dark matter inner density profile to be cuspy with the slope consistent with -1, in agreement with expectations.

  1. LENSED: a code for the forward reconstruction of lenses and sources from strong lensing observations

    Science.gov (United States)

    Tessore, Nicolas; Bellagamba, Fabio; Metcalf, R. Benton

    2016-12-01

    Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present LENSED, a new code which performs forward parametric modelling of strong lenses. LENSED takes advantage of a massively parallel ray-tracing kernel to perform the necessary calculations on a modern graphics processing unit (GPU). This makes the precise rendering of the background lensed sources much faster, and allows the simultaneous optimization of tens of parameters for the selected model. With a single run, the code is able to obtain the full posterior probability distribution for the lens light, the mass distribution and the background source at the same time. LENSED is first tested on mock images which reproduce realistic space-based observations of lensing systems. In this way, we show that it is able to recover unbiased estimates of the lens parameters, even when the sources do not follow exactly the assumed model. Then, we apply it to a subsample of the Sloan Lens ACS Survey lenses, in order to demonstrate its use on real data. The results generally agree with the literature, and highlight the flexibility and robustness of the algorithm.

  2. Contaminant Case Report: Spectacled eider (Somateria fischeri) eggs and feathers from the Yukon-Kuskokwim Delta, Alaska

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — We collected spectacled eider (Somateria fischeri) eggs and shed breast contour feathers from nests on the Yukon-Kuskokwim Delta, Alaska, in 1992 to evaluate...

  3. Spectacled Eiders (Somateria fischeri) capture and resight records, Kashunuk River, Yukon-Kuskokwim Delta, Alaska, 1995-2002

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Data set containing capture and band resight data associated with marked Spectacled Eiders, observed near the Kashunuk River, within the Yukon-Kuskokwim Delta, Alaska.

  4. Lenses for JWST

    Science.gov (United States)

    Ebeling, Harald; Richard, Johan; Kneib, Jean-Paul; Repp, Andrew; Atek, Hakim; Egami, Eiichi; Windhorst, Rogier; Edge, Alastair

    2016-08-01

    JWST will dramatically advance our knowledge and understanding of the first generations of galaxies at z>10, their role in the re-ionization of the Universe, and the evolutionary processes that gave rise to the complexity and diversity of galaxies at the current epoch. As demonstrated by HST legacy projects like CLASH and the Hubble Frontier Fields, gravitational amplification by massive galaxy clusters can significantly extend the depth of the required observations. However, for JWST, reducing any diffuse background light will be just as crucial. We here propose Spitzer/IRAC observations of six massive cluster lenses, specifically selected as candidates for observation with JWST. By (a) quantifying the amount of intra-cluster light and (b) enabling us to improve our current lens models, the data resulting from the requested observations will be instrumental for the final selection of cluster targets that maximize the scientific returns of deep JWST observations.

  5. Lensed Quasar Hosts

    CERN Document Server

    Peng, C Y; Rix, H W; Keeton, C R; Falco, E E; Kochanek, C S; Lehár, J; McLeod, B A; Peng, Chien Y.; Impey, Chris D.; Rix, Hans-Walter; Keeton, Charles R.; Falco, Emilio E.; Kochanek, Chris S.; Lehar, Joseph; Leod, Brian A. Mc

    2006-01-01

    Gravitational lensing assists in the detection of quasar hosts by amplifying and distorting the host light away from the unresolved quasar core images. We present the results of HST observations of 30 quasar hosts at redshifts 1 1.7 is a factor of 3--6 higher than the local value. But, depending on the stellar content the ratio may decline at z>4 (if E/S0-like), flatten off to 6--10 times the local value (if Sbc-like), or continue to rise (if Im-like). We infer that galaxy bulge masses must have grown by a factor of 3--6 over the redshift range 3>z>1, and then changed little since z~1. This suggests that the peak epoch of galaxy formation for massive galaxies is above z~1. We also estimate the duty cycle of luminous AGNs at z>1 to be ~1%, or 10^7 yrs, with sizable scatter.

  6. Effect of Three-Dimensional Printed Personalized Moisture Chamber Spectacles on the Periocular Humidity.

    Science.gov (United States)

    Moon, Chan Hee; Kim, Jae Yong; Kim, Myoung Joon; Tchah, Hungwon; Lim, Byeong Gak; Chung, Jin Kwon

    2016-01-01

    Purpose. To assess the effect of three-dimensional (3D) printed personalized moisture chamber spectacles (PMCS) on the periocular humidity. Methods. Facial computed tomography (CT) scanning was conducted on 10 normal subjects. PMCS was designed based on volume rendered CT images and produced using a 3D printer. Periocular humidity of PMCS and commercially available uniformed moisture chamber spectacles (UMCS) were measured for 30 minutes via microhydrometer. Results. The mean ambient humidity was 15.76 ± 1.18%. The mean periocular humidity was 52.14 ± 3.00% in PMCS and 37.67 ± 8.97% in UMCS. The difference was significant (P 3D printer provides appropriate fitness for the semiclosed humid chamber. PMCS showed higher performance than UMCS. The wearing of PMCS would be an effective method to provide high enough periocular humidity in low humidity environment.

  7. Cross-correlating Planck CMB lensing with SDSS: lensing-lensing and galaxy-lensing cross-correlations

    Science.gov (United States)

    Singh, Sukhdeep; Mandelbaum, Rachel; Brownstein, Joel R.

    2017-01-01

    We present results from cross-correlating Planck cosmic microwave background (CMB) lensing maps with the Sloan Digital Sky Survey (SDSS) galaxy lensing shape catalogue and BOSS (Baryon Oscillation Spectroscopic Survey) galaxy catalogues. For galaxy position versus CMB lensing cross-correlations, we measure the convergence signal around the galaxies in configuration space, using the BOSS LOWZ (z ˜ 0.30) and CMASS (z ˜ 0.57) samples. With fixed Planck 2015 cosmology, doing a joint fit with the galaxy clustering measurement, for the LOWZ (CMASS) sample we find a galaxy bias bg = 1.75 ± 0.04 (1.95 ± 0.02) and galaxy-matter cross-correlation coefficient rcc = 1.0 ± 0.2 (0.8 ± 0.1) using 20 < rp < 70 h-1 Mpc, consistent with results from galaxy-galaxy lensing. Using the same scales and including the galaxy-galaxy lensing measurements, we constrain Ωm = 0.284 ± 0.024 and relative calibration bias between the CMB lensing and galaxy lensing to be b_γ =0.82^{+0.15}_{-0.14}. The combination of galaxy lensing and CMB lensing also allows us to measure the cosmological distance ratios (with zl ˜ 0.3, zs ˜ 0.5) R=D_s D_{l,*}/D_{* D_{l,s}}=2.68± 0.29, consistent with predictions from the Planck 2015 cosmology (R=2.35). We detect the galaxy position-CMB convergence cross-correlation at small scales, rp < 1 h-1 Mpc, and find consistency with lensing by NFW haloes of mass Mh ˜ 1013 h-1 M⊙. Finally, we measure the CMB lensing-galaxy shear cross-correlation, finding an amplitude of A = 0.76 ± 0.23 (zeff = 0.35, θ < 2°) with respect to Planck 2015 Λ cold dark matter predictions (1σ level consistency). We do not find evidence for relative systematics between the CMB and SDSS galaxy lensing.

  8. Burst Into Action: The Changing Spectacle of Glamour Heroines in Contemporary Hong Kong Cinema

    OpenAIRE

    2013-01-01

    My question for now is: in what ways have the new currents of transnationality affected existing forms of cultural sensibility in the ‘post-colony’? Realised as a system of representation of the global popular, recent articulations of popular experience tend to be absorbed into generic cross-cultural media representations shared on the glocal level of operation by cultural producers, consumers and practitioners across geographical borders. In this paper, I shall focus on the changing spectacl...

  9. Comparison of progressive addition lenses for general purpose and for computer vision: an office field study.

    Science.gov (United States)

    Jaschinski, Wolfgang; König, Mirjam; Mekontso, Tiofil M; Ohlendorf, Arne; Welscher, Monique

    2015-05-01

    Two types of progressive addition lenses (PALs) were compared in an office field study: 1. General purpose PALs with continuous clear vision between infinity and near reading distances and 2. Computer vision PALs with a wider zone of clear vision at the monitor and in near vision but no clear distance vision. Twenty-three presbyopic participants wore each type of lens for two weeks in a double-masked four-week quasi-experimental procedure that included an adaptation phase (Weeks 1 and 2) and a test phase (Weeks 3 and 4). Questionnaires on visual and musculoskeletal conditions as well as preferences regarding the type of lenses were administered. After eight more weeks of free use of the spectacles, the preferences were assessed again. The ergonomic conditions were analysed from photographs. Head inclination when looking at the monitor was significantly lower by 2.3 degrees with the computer vision PALs than with the general purpose PALs. Vision at the monitor was judged significantly better with computer PALs, while distance vision was judged better with general purpose PALs; however, the reported advantage of computer vision PALs differed in extent between participants. Accordingly, 61 per cent of the participants preferred the computer vision PALs, when asked without information about lens design. After full information about lens characteristics and additional eight weeks of free spectacle use, 44 per cent preferred the computer vision PALs. On average, computer vision PALs were rated significantly better with respect to vision at the monitor during the experimental part of the study. In the final forced-choice ratings, approximately half of the participants preferred either the computer vision PAL or the general purpose PAL. Individual factors seem to play a role in this preference and in the rated advantage of computer vision PALs. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

  10. Resistance to the Society of the Spectacle: the “nikutai” in Murobushi Kō

    Directory of Open Access Journals (Sweden)

    Katja Centonze

    2009-09-01

    Full Text Available As Guy Debord has predicted, in this society of the spectacle, where “the real consumer becomes a consumer of illusions”, we are moved by the principle of commodity fetishism. In such a context commodity is a factually real illusion, and its general manifestation is the spectacle. The determination of the 1960s Japanese avant-garde to contrast and protest against the capitalistic mechanism through alternative performative acts is not central any more. Compared to those years, abusive use of power today is probably even more dangerous, since its exponential and pervasive diffusion leads to a condition in which power is omnipresent. As a result, the idea that the avant-garde can be a mechanism for resisting capitalism has been thoroughly questioned. Also the radical aims born in one of the most revolutionary body-theatre, butō, seem to have faded into a static proposition. As a banner of resistance to the society of the spectacle, trying to find out a context of radical nikutai (the immediacy of the material body in performance as advanced by the founder of butō Hijikata Tatsumi and of politics of the body, a good example is the work of the performer and choreographer Murobushi Kō. This paper will analyse in specific the renovating intent visible in Murobushi’s project Experimental Body realised with his group Kō&Edge Co. in performances as Bibō no aozora (Shinjuku Park Tower Hall, 2003, Heels (Kagurazaka Die Pratze, 2004.

  11. Lensed: a code for the forward reconstruction of lenses and sources from strong lensing observations

    CERN Document Server

    Tessore, Nicolas; Metcalf, R Benton

    2015-01-01

    Robust modelling of strong lensing systems is fundamental to exploit the information they contain about the distribution of matter in galaxies and clusters. In this work, we present Lensed, a new code which performs forward parametric modelling of strong lenses. Lensed takes advantage of a massively parallel ray-tracing kernel to perform the necessary calculations on a modern graphics processing unit (GPU). This makes the precise rendering of the background lensed sources much faster, and allows the simultaneous optimisation of tens of parameters for the selected model. With a single run, the code is able to obtain the full posterior probability distribution for the lens light, the mass distribution and the background source at the same time. Lensed is first tested on mock images which reproduce realistic space-based observations of lensing systems. In this way, we show that it is able to recover unbiased estimates of the lens parameters, even when the sources do not follow exactly the assumed model. Then, we...

  12. Plasticity theory

    CERN Document Server

    Lubliner, Jacob

    2008-01-01

    The aim of Plasticity Theory is to provide a comprehensive introduction to the contemporary state of knowledge in basic plasticity theory and to its applications. It treats several areas not commonly found between the covers of a single book: the physics of plasticity, constitutive theory, dynamic plasticity, large-deformation plasticity, and numerical methods, in addition to a representative survey of problems treated by classical methods, such as elastic-plastic problems, plane plastic flow, and limit analysis; the problem discussed come from areas of interest to mechanical, structural, and

  13. Phakic Intraocular Collamer Lens (Visian ICL) Implantation for Correction of Myopia in Spectacle-Aversive Special Needs Children.

    Science.gov (United States)

    Tychsen, Lawrence; Faron, Nicholas; Hoekel, James

    2017-03-01

    A subset of children with high anisometropia or isoametropia and neurobehavioral disorders have chronic difficulties with spectacle or contact lens wear. We report the results of refractive surgery in a series of these children treated using bilateral or unilateral intraocular collamer lens (Visian ICL) implantation for moderate to high myopia. Prospective nonrandomized cohort study. Clinical course and outcome data were collated prospectively for 40 implanted eyes in 23 children (mean age 10.2 ± 5.3 years, range, 1.8-17 years). Myopia ranged from -3.0 to -14.5 diopters (D), mean -9.2 ± 3.5 D. Goal refraction was plano to +1 D. Correction was achieved by sulcus implantation of a Visian ICL (STAAR Surgical, Monrovia, California, USA) under general anesthesia. Mean follow-up was 15.1 months (range, 6-22 months). Thirty-five eyes (88%) were corrected to within ±1.0 D of goal refraction; the other 5 (12%) were corrected to within 1.5 D. Uncorrected distance visual acuity improved substantially in all eyes (from mean 20/1050 [logMAR 1.72] to mean 20/42 [logMAR 0.48]). Spherical regression at last follow-up was an average of +0.59 D. Visuomotor comorbidities (eg, amblyopia, nystagmus, foveopathy, optic neuropathy) accounted for residual postoperative subnormal visual acuity. Thirteen of the 23 children (57%) had a neurobehavioral disorder (eg, developmental delay/intellectual disability/mental retardation, Down syndrome, cerebral palsy, autism spectrum disorder). Eighty-five percent (11/13) of those children were reported to have enhanced visual awareness, attentiveness, or social interactions. Endothelial cell density was measureable in 6 cooperative children (10 eyes), showing an average 1% decline. Central corneal thickness, measured in all children, increased an average of 8 μm. Two children (8%) required unplanned return to the operating room on the first postoperative day to alleviate pupillary block caused by a nonpatent iridotomy. No other

  14. Planar Lenses at Visible Wavelengths

    CERN Document Server

    Khorasaninejad, Mohammadreza; Devlin, Robert C; Oh, Jaewon; Zhu, Alexander Y; Capasso, Federico

    2016-01-01

    Sub-wavelength resolution imaging requires high numerical aperture (NA) lenses, which are bulky and expensive. Metasurfaces allow the miniaturization of conventional refractive optics into planar structures. We show that high-aspect-ratio titanium dioxide metasurfaces can be fabricated and designed as meta-lenses with NA = 0.8. Diffraction-limited focusing is demonstrated at wavelengths of 405 nm, 532 nm, and 660 nm with corresponding efficiencies of 86%, 73%, and 66%. The meta-lenses can resolve nanoscale features separated by sub-wavelength distances and provide magnification as high as 170x with image qualities comparable to a state-of-the-art commercial objective. Our results firmly establish that meta-lenses can have widespread applications in laser-based microscopy, imaging, and spectroscopy.

  15. The Thirring-Lense Effect

    Science.gov (United States)

    Embacher, Franz

    The Thirring-Lense effect is the phenomenon that an observer near a rotating mass, being in a state which is non-rotating with respect to the rest of the universe, experiences extra inertial forces, i.e. becomes dizzy. The first anticipation of the effect goes back to Ernst Mach; its first quantitative prediction on the basis of general relativity was given by Hans Thirring and Joseph Lense. Almost ninety years later, the effect seems to be experimentally verified.

  16. Visual Outcomes, Patient Satisfaction and Spectacle Independence with a Trifocal Diffractive Intraocular Lens

    Science.gov (United States)

    Kretz, Florian Tobias Alwin; Choi, Chul Young; Müller, Matthias; Gerl, Matthias; Gerl, Ralf Helmar

    2016-01-01

    Purpose To evaluate visual outcomes following implantation of a trifocal diffractive intraocular lens (IOL) and to analyze their correlation with patient satisfaction and ease of performing daily tasks. Methods This was a prospective study enrolling 100 eyes of 50 patients undergoing cataract surgery with implantation of trifocal IOL AT LISA tri 839MP. Visual and refractive outcomes were evaluated during a 3-month follow-up. Postoperatively, a questionnaire was used to evaluate patient satisfaction with regard to surgical outcome, spectacle independence, perception of photic phenomena, and ease of performing some vision-related activities. Results A total of 91%, 87%, and 79% of eyes achieved a monocular uncorrected distance, near, and intermediate visual acuity of 0.1 logarithm of the minimum angle of resolution or better, respectively. After the surgery, 96% of the patients could perform their daily activities without problems. The mean spectacle independence scores for reading, doing computer work, and for distance were 10.33 ± 12.47, 5.71 ± 11.90, and 3.92 ± 9.77, respectively (scale: 0 = no spectacles needed; 40 = spectacles always needed). No correlation was found between spectacle independence and visual outcome (-0.101 ≤ r ≤ 0.244, p ≥ 0.087). Mean scores (0 = no symptoms; 40 = strong symptoms) for glare at night, ghost images, and halos were 15.15 ± 12.02, 4.49 ± 7.92, and 13.34 ± 10.82, respectively. No correlation was found between photic phenomena and visual outcome (-0.199 ≤ r ≤ 0.209, p ≥ 0.150). A total of 80% of patients reported satisfaction with the surgery outcome, and 86% would recommend the surgery to friends and family. Conclusions Implantation of the AT LISA tri 839MP IOL after cataract surgery provides effective visual restoration associated with a minimal level of photic phenomena, a positive impact on the performance of vision-related daily activities, and a high level of postoperative patient satisfaction. PMID:27247517

  17. Results of Application of Rigid Gas Permeable Contact Lenses in Patients with Keratoconus

    Directory of Open Access Journals (Sweden)

    Esin Yazar

    2013-12-01

    Full Text Available Purpose: The aim of this study was to evaluate the long-term results of visual rehabilitation provided by rigid gas permeable contact lenses (RGPCL in patients with keratoconus. Material and Method: RGPCL were practiced on a total of 267 eyes of 144 patients with keratoconus who had no previous eye disease and surgery. These eyes were evaluated in 4 groups according to their keratometry values, visual acuity (VA, progression, and complications. Paired t-test was used in statistical evaluations performed by SPSS for Windows (version 15.0. Results: Keratoconus was classified as mild, moderate, advanced, and severe according to mean keratometry values in 39 (14.6%, 80 (30%, 128 (47.9%, and 20 (7.5% eyes, respectively. Disease was unilateral in 2 patients (1.38%. Significant steeping was determined in comparison of K1 and K2 values at first and last follow-up visits of patients in mild, moderate and advanced keratoconus groups. VA obtained by application of RGPCL in all patient groups was significantly better than the VA corrected by spectacles (p<0.0001. No significant change was determined in mean VA obtained by RGPCL during disease course. In comparison of mean radius of curvature of first and second contact lenses, second contact lens was found to be significantly steeper in advanced and severe keratoconus groups. Corneal erosions, acute hydrops, allergic conjunctivitis, and dry eye were found in 15 (5.6%, 5 (1.8%, 19 (7.1%, and 29 (10.8% eyes, respectively. One patient ceased using lenses due to giant papillary conjunctivitis. Discussion: RGPCL were successfully applied to patients in all groups. Although it is a laborious and time-consuming method, application of contact lenses still seem to be one of the primary options in treatment of keratoconus in the meaning of gaining a satisfactory VA and less complication risk. (Turk J Ophthalmol 2013; 43: 432-6

  18. Plastic Jellyfish.

    Science.gov (United States)

    Moseley, Christine

    2000-01-01

    Presents an environmental science activity designed to enhance students' awareness of the hazards of plastic waste for wildlife in aquatic environments. Discusses how students can take steps to reduce the effects of plastic waste. (WRM)

  19. The M31 pixel lensing plan campaign: MACHO lensing and self-lensing signals

    Energy Technology Data Exchange (ETDEWEB)

    Calchi Novati, S.; Scarpetta, G. [Istituto Internazionale per gli Alti Studi Scientifici (IIASS), Via Pellegrino 19, I-84019 Vietri Sul Mare (Italy); Bozza, V. [Dipartimento di Fisica E. R. Caianiello, Università di Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Bruni, I.; Gualandi, R. [INAF, Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Dall' Ora, M. [INAF, Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, I-80131 Napoli (Italy); De Paolis, F.; Ingrosso, G.; Nucita, A.; Strafella, F. [Dipartimento di Matematica e Fisica E. De Giorgi, Università del Salento, CP 193, I-73100 Lecce (Italy); Dominik, M. [SUPA, University of St Andrews, School of Physics and Astronomy, North Haugh, St Andrews, KY16 9SS (United Kingdom); Jetzer, Ph. [Institute for Theoretical Physics, University of Zürich, Winterthurerstrasse 190, 8057 Zürich (Switzerland); Mancini, L. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Safonova, M.; Subramaniam, A. [Indian Institute of Astrophysics, Bangalore 560 034 (India); Sereno, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino (Italy); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Collaboration: PLAN Collaboration

    2014-03-10

    We present the final analysis of the observational campaign carried out by the PLAN (Pixel Lensing Andromeda) collaboration to detect a dark matter signal in form of MACHOs through the microlensing effect. The campaign consists of about 1 month/year observations carried out over 4 years (2007-2010) at the 1.5 m Cassini telescope in Loiano (Astronomical Observatory of BOLOGNA, OAB) plus 10 days of data taken in 2010 at the 2 m Himalayan Chandra Telescope monitoring the central part of M31 (two fields of about 13' × 12.'6). We establish a fully automated pipeline for the search and the characterization of microlensing flux variations. As a result, we detect three microlensing candidates. We evaluate the expected signal through a full Monte Carlo simulation of the experiment completed by an analysis of the detection efficiency of our pipeline. We consider both 'self lensing' and 'MACHO lensing' lens populations, given by M31 stars and dark matter halo MACHOs, in M31 and the Milky Way, respectively. The total number of events is consistent with the expected self-lensing rate. Specifically, we evaluate an expected signal of about two self-lensing events. As for MACHO lensing, for full 0.5(10{sup –2}) M {sub ☉} MACHO halos, our prediction is for about four (seven) events. The comparatively small number of expected MACHO versus self-lensing events, together with the small number statistics at our disposal, do not enable us to put strong constraints on that population. Rather, the hypothesis, suggested by a previous analysis, on the MACHO nature of OAB-07-N2, one of the microlensing candidates, translates into a sizeable lower limit for the halo mass fraction in form of the would-be MACHO population, f, of about 15% for 0.5 M {sub ☉} MACHOs.

  20. Effects of Lead Exposure, Environmental Conditions, and Metapopulation Processes on Population Dynamics of Spectacled Eiders.

    Science.gov (United States)

    Flint, Paul L.; Grand, James B.; Petersen, Margaret; Robert Rockwell,

    2016-01-01

    Spectacled eider Somateria fischeri numbers have declined and they are considered threatened in accordance with the US Endangered Species Act throughout their range. We synthesized the available information for spectacled eiders to construct deterministic, stochastic, and metapopulation models for this species that incorporated current estimates of vital rates such as nest success, adult survival, and the impact of lead poisoning on survival. Elasticities of our deterministic models suggested that the populations would respond most dramatically to changes in adult female survival and that the reductions in adult female survival related to lead poisoning were locally important. We also examined the sensitivity of the population to changes in lead exposure rates. With the knowledge that some vital rates vary with environmental conditions, we cast stochastic models that mimicked observed variation in productivity. We also used the stochastic model to examine the probability that a specific population will persist for periods of up to 50 y. Elasticity analysis of these models was consistent with that for the deterministic models, with perturbations to adult female survival having the greatest effect on population projections. When used in single population models, demographic data for some localities predicted rapid declines that were inconsistent with our observations in the field. Thus, we constructed a metapopulation model and examined the predictions for local subpopulations and the metapopulation over a wide range of dispersal rates. Using the metapopulation model, we were able to simulate the observed stability of local subpopulations as well as that of the metapopulation. Finally, we developed a global metapopulation model that simulates periodic winter habitat limitation, similar to that which might be experienced in years of heavy sea ice in the core wintering area of spectacled eiders in the central Bering Sea. Our metapopulation analyses suggested that no

  1. Visual impairment and spectacle coverage rate in Baoshan district, China: population-based study

    Science.gov (United States)

    2013-01-01

    Background To investigate the prevalence and risk factors of visual impairment associated with refractive error and the unmet need for spectacles in a special suburban senior population in Baoshan District of Shanghai, one of several rural areas undergoing a transition from rural to urban area, where data of visual impairment are limited. Methods The study was a population based survey of 4545 Chinese aged (age: >60 years or older ) at Baoshan, Shanghai, in 2009. One copy of questionnaire was completed for each subject. Examinations included a standardized refraction and measurement of presenting and best corrected visual acuity (BCVA) as well as tonometry, slit lamp biomicroscopy, and fundus photography. Results The prevalence of mild (6/12 to 6/18), moderate (6/18 to 6/60) and severe visual impairment was 12.59%, 8.38% and 0.44%, respectively, and 5.26%, 3.06% and 0.09% with refractive correction. Visual impairment was associated with age, gender, education and career, but not insurance . The prevalence of correctable visual impairment was 5.81% (using 6/18 cutoff) and 13.18% (using 6/12 cutoff). Senior people and women were significantly at a higher risk of correctable visual impairment, while the well-educated on the contrary. The prevalence of undercorrected refractive error (improves by 2 or more lines with refraction) was 24.84%, and the proportion with undercorrected refractive error for mild, moderate , severe and no visual impairment was 61.54%, 67.98%, 60.00% and 14.10%, respectively. The spectacle coverage rate was 44.12%. Greater unmet need for spectacles was observed among elderly people, females, non-peasant, and subjects with less education and astigmatism only. Conclusions High prevalence of visual impairment, visual impairment alleviated by refractive correction, and low spectacle coverage existed among the senior population in Baoshan District of Shanghai. Education for the public of the importance of regular examination and appropriate and

  2. The Collision between Reality and Dream-Symbolic significance of stage spectacle in The Glass Menagerie

    Institute of Scientific and Technical Information of China (English)

    陈方元

    2014-01-01

    In Tennessee Williams’masterpiece The Glass Menagerie, the most remarkable feature is considered to be the success-ful employment of symbolism. Through the textual analysis, this paper thus gives a systematic analysis of some important symbolic images in stage spectacle, including“lighting”,“screen”,“fire-escape”,“unicorn,”“Jonquil”and“father’s photo.”These sym-bols effectively highlight the theme-the collision between reality and dream, which vividly exposes the tragic living situation of the lower class in America during the Great Depression.

  3. The politics оf spectacle: Italian music аnd Fascist propaganda

    Directory of Open Access Journals (Sweden)

    Illiano Roberto

    2012-01-01

    Full Text Available Propaganda played a very important role during Fascism; the kind of propaganda used by Mussolini to build a totalitarian state was to a very large extent based on his own personality cult, on the myth of the leader. Despite the disastrous outcome of the Mussolini regime, the propaganda has outlived Mussolini himself. Cultivating the image therefore becomes an essential part of the mechanism of generating consensus, anticipating by more than half a century the politics of spectacle used today throughout the world.

  4. A new method for getting the three-dimensional curve of the groove of a spectacle frame by optical measuring

    Science.gov (United States)

    Rückwardt, M.; Göpfert, A.; Schnellhorn, M.; Correns, M.; Rosenberger, M.; Linß, G.

    2010-07-01

    Precise measuring of spectacle frames is an important field of quality assurance for opticians and their customers. Different supplier and a number of measuring methods are available but all of them are tactile ones. In this paper the possible employment of optical coordinate measuring machines is discussed for detecting the groove of a spectacle frame. The ambient conditions like deviation and measuring time are even multifaceted like quantity of quality characteristics and measuring objects itself and have to be tested. But the main challenge for an optical coordinate measuring machine is the blocked optical path, because the device under test is located behind an undercut. In this case it is necessary to deflect the beam of the machine for example with a rotating plane mirror. In the next step the difficulties of machine vision connecting to the spectacle frame are explained. Finally first results are given.

  5. Small vertebrates in the spectacled bear’s diet (Tremarctos ornatus Cuvier, 1825 in the north of Peru

    Directory of Open Access Journals (Sweden)

    Fiorella N. Gonzales

    2016-05-01

    Full Text Available There have been numerous studies about Spectacled bear´s diet, however little is known about the small vertebrates it consumes. This study present nine vertebrate species (seven rodent and two birds as preys of the Spectacled bear, based on the analysis of six feces collected from two locations Upa (Amazonas and Lagunas Arreviatadas (Cajamarca in northern Peru. Six of these records were new food items and a new family Caviidae. Vertebrates were found only in the Upa location. Additionally a sampling of small non flying mammals was conducted in there. Our results suggest that the Spectacled bear would be a generalist species. It prefers plants, however if it finds vertebrates in the environment, it could feed on them.

  6. Fabrication of nanoscale electrostatic lenses

    Science.gov (United States)

    Sinno, I.; Sanz-Velasco, A.; Kang, S.; Jansen, H.; Olsson, E.; Enoksson, P.; Svensson, K.

    2010-09-01

    The fabrication of cylindrical multi-element electrostatic lenses at the nanoscale presents a challenge; they are high-aspect-ratio structures that should be rotationally symmetric, well aligned and freestanding, with smooth edges and flat, clean surfaces. In this paper, we present the fabrication results of a non-conventional process, which uses a combination of focused gallium ion-beam milling and hydrofluoric acid vapor etching. This process makes it possible to fabricate nanoscale electrostatic lenses down to 140 nm in aperture diameter and 4.2 µm in column length, with a superior control of the geometry as compared to conventional lithography-based techniques.

  7. Visual Performance and Optical Quality of Standardized Asymmetric Soft Contact Lenses in Patients With Keratoconus.

    Science.gov (United States)

    Suzaki, Asaki; Maeda, Naoyuki; Fuchihata, Mutsumi; Koh, Shizuka; Nishida, Kohji; Fujikado, Takashi

    2017-06-01

    To evaluate the visual performance and optical quality of a standardized asymmetric soft contact lens (SCL) used for correction of higher-order aberrations (HOAs) in eyes with keratoconus. We included 30 eyes (26 patients) with keratoconus (average K: 45.7 ± 2.3 diopters [D]). The patients were subjected to corneal tomography, aberrometry, measurements of manifest refraction and visual acuity (VA), and visual analog scale (VAS) assessments. The study lenses were made using a molding method and consisted of six standardized types, in which an asymmetric power distribution of approximately 2 to 12 D (2-D step) was used to correct HOAs. The lens type suitable for each eye was selected based on the corneal tomography and aberrometry data. The on-eye performance of the lens was evaluated using aberrometry (4-mm pupil), over refraction, VA, and VAS. The standardized asymmetric SCL improved the best spectacle-corrected VA from -0.07 ± 0.09 to -0.11 ± 0.08 logMAR (P keratoconus who wear rigid gas-permeable lenses.

  8. Refractive ocular conditions and reasons for spectacles renewal in a resource-limited economy

    Directory of Open Access Journals (Sweden)

    Folorunso Francisca N

    2010-05-01

    Full Text Available Abstract Background Although a leading cause of visual impairment and a treatable cause of blindness globally, the pattern of refractive errors in many populations is unknown. This study determined the pattern of refractive ocular conditions, reasons for spectacles renewal and the effect of correction on refractive errors in a resource-limited community. Methods A retrospective review of case records of 1,413 consecutive patients seen in a private optometry practice, Nigeria between January 2006 and July 2007. Results A total number of 1,216 (86.1% patients comprising of (486, 40% males and (730, 60% females with a mean age of 41.02 years SD 14.19 were analyzed. The age distribution peaked at peri-adolescent and the middle age years. The main ocular complaints were spectacles loss and discomfort (412, 33.9%, blurred near vision (399, 32.8% and asthenopia (255, 20.9%. The mean duration of ocular symptoms before consultation was 2.05 years SD 1.92. The most common refractive errors include presbyopia (431, 35.3%, hyperopic astigmatism (240, 19.7% and presbyopia with hyperopia (276, 22.7%. Only (59, 4.9% had myopia. Following correction, there were reductions in magnitudes of the blind (VA Conclusions Adequate correction of refractive errors reduces visual impairment and avoidable blindness and to achieve optimal control of refractive errors in the community, services should be targeted at individuals in the peri-adolescent and the middle age years.

  9. Self-refraction accuracy with adjustable spectacles among children in Ghana.

    Science.gov (United States)

    Ilechie, Alex Azuka; Abokyi, Samuel; Owusu-Ansah, Andrew; Boadi-Kusi, Samuel Bert; Denkyira, Andrew Kofi; Abraham, Carl Halladay

    2015-04-01

    To determine the accuracy of self-refraction (SR) in myopic teenagers, we compared visual and refractive outcomes of self-refracting spectacles (FocusSpecs) with those obtained using cycloplegic subjective refraction (CSR) as a gold standard. A total of 203 eligible schoolchildren (mean [±SD] age, 13.8 [±1.0] years; 59.1% were female) completed an examination consisting of SR with FocusSpecs adjustable spectacles, visual acuity with the logMAR (logarithm of the minimum angle of resolution) chart, cycloplegic retinoscopy, and CSR. Examiners were masked to the SR findings. Wilcoxon signed rank test and paired Student t test were used to compare measures across refraction methods (95% confidence intervals [CIs]). The mean (±SD) spherical equivalent refractive error measured by CSR and SR was -1.22 (±0.49) diopters (D) and -1.66 (±0.73) D, respectively, a statistically significant difference of -0.44 D (p refraction offers acceptable visual and refractive results for young people in a rural setting in Ghana, although myopic inaccuracy in the more negative direction occurred in some children.

  10. Main visual symptoms associated to refractive errors and spectacle need in a Brazilian population

    Science.gov (United States)

    Schellini, Silvana; Ferraz, Fabio; Opromolla, Paula; Oliveira, Laryssa; Padovani, Carlos

    2016-01-01

    AIM To determine the main visual symptoms in a Brazilian population sample, associated to refractive errors (REs) and spectacle need to suggest priorities in preventive programs. METHODS A cross-sectional study was conducted in nine counties of the southeast region of Brazil, using a systematic sampling of households, between March 2004 and July 2005. The population was defined as individuals aged between 1 and 96y, inhabitants of 3600 residences to be evaluated and 3012 households were included, corresponding to 8010 subjects considered for participation in the survey, of whom 7654 underwent ophthalmic examinations. The individuals were evaluated according their demographic data, eye complaints and eye examination including the RE and the need to prescribe spectacles according to age. Statistical analysis was performed using SPSS software package and descriptive analysis using 95% confidence intervals (Pcorrect near vision. Subjects of ≥40 years old were determined to be at high risk of uncorrected REs. These observations can guide intervention programs for the Brazilian population. PMID:27990372

  11. Effect of Three-Dimensional Printed Personalized Moisture Chamber Spectacles on the Periocular Humidity

    Directory of Open Access Journals (Sweden)

    Chan Hee Moon

    2016-01-01

    Full Text Available Purpose. To assess the effect of three-dimensional (3D printed personalized moisture chamber spectacles (PMCS on the periocular humidity. Methods. Facial computed tomography (CT scanning was conducted on 10 normal subjects. PMCS was designed based on volume rendered CT images and produced using a 3D printer. Periocular humidity of PMCS and commercially available uniformed moisture chamber spectacles (UMCS were measured for 30 minutes via microhydrometer. Results. The mean ambient humidity was 15.76±1.18%. The mean periocular humidity was 52.14±3.00% in PMCS and 37.67±8.97% in UMCS. The difference was significant (P<0.001. Additionally, PMCS always demonstrated lower humidity than dew points. Conclusion. PMCS made by 3D printer provides appropriate fitness for the semiclosed humid chamber. PMCS showed higher performance than UMCS. The wearing of PMCS would be an effective method to provide high enough periocular humidity in low humidity environment.

  12. Analysis of optical properties in injection-molded and compression-molded optical lenses.

    Science.gov (United States)

    Wang, Chung Yen; Wang, Pei Jen

    2014-04-10

    Numerical mold-flow simulations and experimental measurements for injection-molded lenses have been investigated in form accuracy on a two-cavity mold with various process conditions. First, form profiles of the molded lenses have been measured together with the corresponding simulated mold-temperature distribution and displacement distribution of the lens in the z direction. A flow-through type layout of cooling channels has been devised for balance of mold-temperature distribution in mold cavities with various parametric distances for assessments in uniformity of temperature distribution. Finally, a compression-molding process is proposed for the post-process of birefringence relaxation as well as adequate form accuracy of lenses. In conclusion, optimization of process parameters to achieve good form accuracy in a multicavity mold with symmetric geometry but nonuniform cooling conditions is difficult. A good design of cooling channels plus optimized process conditions could provide uniform mold-temperature distribution so that molded lenses of good quality would be possible. Then, the profile deviation of lenses could be further compensated by profile geometry corrections. In conclusion, the post-compression-molding process could make birefringence-free plastic lenses with good form accuracy.

  13. Pressure testing of ophthalmic safety lenses: the effects on different materials.

    Science.gov (United States)

    Dain, S J

    1988-07-01

    The procedure of applying pressure to a lens until fracture occurs and the use of the fracture pressure as a measure of lens strength has been proposed as a quantitative alternative to the drop ball test. The fracture pressure or pressure resistance of untempered, thermally tempered, and chemically tempered glass lenses and CR39 lenses were compared. The results for the glass lenses were consistent with workplace experience and previous studies using the drop ball test. The results for glass and CR39 lenses showed the reverse to what was expected. In order to investigate the basis of this difference, a second procedure was followed in which the annulus supporting the lens and the steel ball applying the pressure to the lens were systematically changed. Glass lenses showed a highly statistically significant change in fracture pressure with decreasing ball size and a small but statistically significant change with annulus size. CR39 lenses showed no statistically significant change in fracture pressure with changing ball size but a highly statistically significant increase in fracture pressure with increasing annulus size. The mechanism of fracture is known to differ in the glass and plastics materials and it is concluded that this method should not be used to compare the performance of different materials.

  14. Fabrication of nanoscale electrostatic lenses

    NARCIS (Netherlands)

    Sinno, I.; Sanz-Velasco, A.; Kang, S.; Jansen, H.; Olsson, E.; Enoksson, P.; Svensson, K.

    2010-01-01

    The fabrication of cylindrical multi-element electrostatic lenses at the nanoscale presents a challenge; they are high-aspect-ratio structures that should be rotationally symmetric, well aligned and freestanding, with smooth edges and flat, clean surfaces. In this paper, we present the fabrication r

  15. Weak lensing and cosmological investigation

    CERN Document Server

    Acquaviva, V

    2005-01-01

    In the last few years the scientific community has been dealing with the challenging issue of identifying the dark energy component. We regard weak gravitational lensing as a brand new, and extremely important, tool for cosmological investigation in this field. In fact, the features imprinted on the cosmic microwave background radiation by the lensing from the intervening distribution of matter represent a pretty unbiased estimator, and can thus be used for putting constraints on different dark energy models. This is true in particular for the magnetic-type B-modes of CMB polarization, whose unlensed spectrum at large multipoles (l approximately=1000) is very small even in presence of an amount of gravitational waves as large as currently allowed by the experiments: therefore, on these scales the lensing phenomenon is the only responsible for the observed power, and this signal turns out to be a faithful tracer of the dark energy dynamics. We first recall the formal apparatus of the weak lensing in extended t...

  16. Irlen Lenses and Reading Difficulties.

    Science.gov (United States)

    Hoyt, Creig S.

    1990-01-01

    The article reviews three studies (EC 600 064-066) evaluating the effectiveness of using Irlen tinted lenses with reading-disabled persons. The studies are individually critiqued, and recommendations are offered concerning the methodology of further research. Stressed is the need to determine whether a specific syndrome of scotopic sensitivity…

  17. Optics Demonstrations Using Cylindrical Lenses

    Science.gov (United States)

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  18. Advantages of toric scleral lenses.

    NARCIS (Netherlands)

    Visser, E.S.; Visser, R.; Lier, H.J.J. van

    2006-01-01

    PURPOSE: The purpose of this study was to investigate whether back surface toric scleral lenses stabilized (i.e., returned to their original position after rotation) and how long the return times were. Return time was studied in relation with actual wearing time and comfort; moreover, the performanc

  19. Gravitational lensing by gravitational waves

    OpenAIRE

    Bisnovatyi-Kogan, G. S.; Tsupko, O. Yu.

    2008-01-01

    Gravitational lensing by gravitational wave is considered. We notice that although final and initial direction of photons coincide, displacement between final and initial trajectories occurs. This displacement is calculated analytically for the plane gravitational wave pulse. Estimations for observations are discussed.

  20. Thermal lensing of laser materials

    Science.gov (United States)

    Davis, Mark J.; Hayden, Joseph S.

    2014-10-01

    This paper focuses on the three main effects that can induce wave-front distortion due to thermal lensing in laser gain media: 1) thermo-optic (dn/dT); 2) stress-optic; and 3) surface deformation (e.g., "end-bulging" of a laser rod). Considering the simple case of a side-pumped cylindrical rod which is air- or water-cooled along its length, the internal temperature distribution has long been known to assume a simple parabolic profile. Resulting from this are two induced refractive index variations due to thermo-optic and stress-optic effects that also assume a parabolic profile, but generally not of the same magnitude, nor even of the same sign. Finally, a small deformation on the rod ends can induce a small additional lensing contribution. We had two goals in this study: a) use finite-element simulations to verify the existing analytical expressions due to Koechner1 and Foster and Osterink; and b) apply them to glasses from the SCHOTT laser glass portfolio. The first goal was a reaction to more recent work by Chenais et al. who claimed Koechner made an error in his analysis with regard to thermal stress, throwing into doubt conclusions within studies since 1970 which made use of his equations. However, our re-analysis of their derivations, coupled with our FE modeling, confirmed that the Koechner and Foster and Osterink treatments are correct, and that Chenais et al. made mistakes in their derivation of the thermally-induced strain. Finally, for a nominal laser rod geometry, we compared the thermally-induced optical distortions in LG-680, LG-750, LG-760, LG-770, APG-1, and APG-2. While LG-750, -760, and -770 undergo considerable thermo-optic lensing, their stress-optic lensing is nearly of the same magnitude but of opposite sign, leading to a small total thermal lensing signature.

  1. Characterization of sand lenses embedded in tills

    DEFF Research Database (Denmark)

    Kessler, Timo Christian; Klint, K.E.S.; Nilsson, B.

    2012-01-01

    of the various types of sand lenses is discussed, primarily in relation to the depositional and glaciotectonic processes they underwent. Detailed characterization of sand lenses facilitates such interpretations. Finally, the observations are linked to a more general overview of the distribution of sand lenses......Tills dominate large parts of the superficial sediments on the Northern hemisphere. These glacial diamictons are extremely heterogeneous and riddled with fractures and lenses of sand or gravel. The frequency and geometry of sand lenses within tills are strongly linked to glaciodynamic processes...... occurring in various glacial environments. This study specifically focuses on the appearance and spatial distribution of sand lenses in tills. It introduces a methodology on how to measure and characterize sand lenses in the field with regard to size, shape and degree of deformation. A set of geometric...

  2. EDITORIAL: Focus on Gravitational Lensing

    Science.gov (United States)

    Jain, Bhuvnesh

    2007-11-01

    Gravitational lensing emerged as an observational field following the 1979 discovery of a doubly imaged quasar lensed by a foreground galaxy. In the 1980s and '90s dozens of other multiply imaged systems were observed, as well as time delay measurements, weak and strong lensing by galaxies and galaxy clusters, and the discovery of microlensing in our galaxy. The rapid pace of advances has continued into the new century. Lensing is currently one of best techniques for finding and mapping dark matter over a wide range of scales, and also addresses broader cosmological questions such as understanding the nature of dark energy. This focus issue of New Journal of Physics presents a snapshot of current research in some of the exciting areas of lensing. It provides an occasion to look back at the advances of the last decade and ahead to the potential of the coming years. Just about a decade ago, microlensing was discovered through the magnification of stars in our galaxy by invisible objects with masses between that of Jupiter and a tenth the mass of the Sun. Thus a new component of the mass of our galaxy, dubbed MACHOs, was established (though a diffuse, cold dark matter-like component is still needed to make up most of the galaxy mass). More recently, microlensing led to another exciting discovery—of extra-solar planets with masses ranging from about five times that of Earth to that of Neptune. We can expect many more planets to be discovered through ongoing surveys. Microlensing is the best technique for finding Earth mass planets, though it is not as productive overall as other methods and does not allow for follow up observations. Beyond planet hunting, microlensing has enabled us to observe previously inaccessible systems, ranging from the surfaces of other stars to the accretion disks around the black holes powering distant quasars. Galaxies and galaxy clusters at cosmological distances can produce dramatic lensing effects: multiple images of background galaxies

  3. Contact lenses in the U.S. Army attack helicopter environment: an interim report.

    Science.gov (United States)

    Lattimore, M R

    1992-05-01

    Recent technological advances have had a major impact on military aviation. While modern methods of providing visual information via electro-optics/visionics systems have extended the aviator's operational envelope, these devices are becoming increasingly incompatible with spectacle wear. Since close to 22 percent of Army aviators are ametropic (spectacle wearing), alternative means of providing a refractive error correction need to be investigated. One alternative being considered is the use of a contact lens correction. Since November 1988, the U.S. Army Aeromedical Research Laboratory (USAARL) has been conducting two AH-64 "Apache" contact lens research projects in order to develop a comprehensive database on contact lens wear in a variety of environments. A three-tier contact lens fitting system is being used: two different types of soft lenses and one rigid gas permeable (RGP) lens type. The wearing schedule is set at a maximum of 7 days/6 nights of extended lens wear. Fundamental operational data is being chronicled by unit flight surgeons. Standard clinical data is being used in ongoing command deliberations on future medical policy decisions concerning contact lens wear by Army aviators. Basic research information is being gathered in an effort to determine the fundamental physiological response of the cornea to the presence of a contact lens. Data through July 31, 1990 are presented. The subjective assessment of contact lens applications within the aviation community is universal acceptance. While current clinical data indicate some ocular health risk, flight safety risks are minimal. Establishment of long-term contact lens efficacy will likely depend on the ensuing analysis of physiological data.

  4. Plastics Technology.

    Science.gov (United States)

    Barker, Tommy G.

    This curriculum guide is designed to assist junior high schools industrial arts teachers in planning new courses and revising existing courses in plastics technology. Addressed in the individual units of the guide are the following topics: introduction to production technology; history and development of plastics; safety; youth leadership,…

  5. Gravitational Lensing - Einstein's Unfinished Symphony

    CERN Document Server

    Treu, Tommaso

    2014-01-01

    Gravitational lensing - the deflection of light rays by gravitating matter - has become a major tool in the armoury of the modern cosmologist. Proposed nearly a hundred years ago as a key feature of Einstein's theory of General Relativity, we trace the historical development since its verification at a solar eclipse in 1919. Einstein was apparently cautious about its practical utility and the subject lay dormant observationally for nearly 60 years. Nonetheless there has been rapid progress over the past twenty years. The technique allows astronomers to chart the distribution of dark matter on large and small scales thereby testing predictions of the standard cosmological model which assumes dark matter comprises a massive weakly-interacting particle. By measuring distances and tracing the growth of dark matter structure over cosmic time, gravitational lensing also holds great promise in determining whether the dark energy, postulated to explain the accelerated cosmic expansion, is a vacuum energy density or a...

  6. Biomimetic Gradient Index (GRIN) Lenses

    Science.gov (United States)

    2006-01-01

    optics include single lenses inspired by cephalopod (octopus) eyes and a three-lens, wide field of view, optical system for a surveillance sensor...camera. Details are easily resolv- able with the polymer lens. This lens system was installed on an Evolution unmanned aerial vehicle (UAV) with a...lens system was installed in an NRL Evolution UAV and used to record video images at a height of up to 1000 ft. The index gradients in the polymer

  7. RELICS: Reionization Lensing Cluster Survey

    Science.gov (United States)

    Coe, Dan A.; RELICS Team

    2017-01-01

    Hubble and Spitzer imaging programs observing galaxy cluster lenses have delivered some of the highest redshift galaxy candidates to date (z ~ 9 - 11, or 540 - 410 Myr after the Big Bang). These magnified galaxies are intrinsically faint, and thus more representative of the sources believed to be primarily responsible for reionization. Magnified galaxies are also observed brightly enough to be prime targets for detailed follow-up study with current and future observatories, including JWST. Building on the successes of CLASH and the Frontier Fields, we have begun RELICS, the Reionization Lensing Cluster Survey. By observing 41 massive clusters for the first time at infrared wavelengths, RELICS will deliver more of the best and brightest high-redshift candidates to the community in time for the November 2017 JWST GO Cycle 1 call for proposals. I will present our early results. I will also discuss prospects for JWST to follow-up known candidates and discover new galaxies at even higher redshifts (z > 11). The discovery efficiency gains from lensing will be even more pronounced at z > 11 if luminosity function faint end slopes are steeper than alpha ~ -2, as suggested by current models and observational extrapolations.

  8. Gravitational lensing in plasmic medium

    Energy Technology Data Exchange (ETDEWEB)

    Bisnovatyi-Kogan, G. S., E-mail: gkogan@iki.rssi.ru; Tsupko, O. Yu., E-mail: tsupko@iki.rssi.ru [Russian Academy of Sciences, Space Research Institute (Russian Federation)

    2015-07-15

    The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.

  9. Uncontrolled Selling of Contact Lenses

    Directory of Open Access Journals (Sweden)

    Cem Sundu

    2015-05-01

    Full Text Available Objectives: To evaluate the opticians’ perspective about selling and applying contact lenses (CL in the provincial centre of Mersin. Materials and Methods: Twenty opticians who work in the 4 main districts in the provincial centre of Mersin were included in the study. A questionnaire form which was prepared before was filled out by the participants. Results: Seventy-eight percent of the opticians were selling CL without prescription, whereas 25% also carried out its fitting. Seventyfive percent of the participants did not get any education about contact lenses, while 65% of them were feeling themselves disqualified about CLs. Furthermore, half of the participants did not have enough knowledge about the complications associated with CL usage and 75% of them wanted to receive information about CLs. Conclusion: As a result of the questionnaire, we found out that a significant part of the participants were both selling and fitting contact lenses without prescription. We believe that auditing the opticians is as important as educating the contact lens users. (Turk J Ophthalmol 2015; 45: 102-104

  10. Tragédie et ballet : enjeux d’un spectacle mixte

    OpenAIRE

    Naudeix, Laura

    2016-01-01

    Le ballet est l’une des composantes les plus remarquables des spectacles donnés dans les collèges jésuites, ils participent à la magnificence qui entoure les remises des prix, en allant parfois jusqu’à constituer le cadre même de l’ensemble de la représentation offerte au public : tragédie et distribution des prix de fin d’année compris, lieu spectaculaire par excellence, et ce d’autant plus que la plupart des autres collèges n’utilisent pas la danse, voire la proscrivent avec énergie des rep...

  11. The Spectacle of Violence in Contemporary Mexico: From femicide to juvenicidio (young killing

    Directory of Open Access Journals (Sweden)

    Mariana Berlanga Gayón

    2015-12-01

    Full Text Available Images of violence began to dot (and cover the map of Mexico in 2006, just after then-president Felipe Calderón declared war on drugs and drug trafficking. The number of cadavers multiplied. Some made their debut in mass graves; others just “disappeared”. Still others were exposed in public places, thus obliging citizens to co-exist with this horror. Pictures of mutilated corpses became an everyday sight. The spectacle of violence in Mexico, however, dates from the nineties with the serial killings of women in Cuidad Juárez and other northern cities. Femicide inaugurated an expressive dimension of violence that later was displaced by other subjects, other patterns of extreme violence. In this article I analyze the specificities and continuities of violence in Mexico from a visual perspective: What are the visible and invisible continuities among these forms of violence? To what mechanisms of control do these forms of violence submit themselves?

  12. Microscope and spectacle: on the complexities of using new visual technologies to communicate about wildlife conservation.

    Science.gov (United States)

    Verma, Audrey; van der Wal, René; Fischer, Anke

    2015-11-01

    Wildlife conservation-related organisations increasingly employ new visual technologies in their science communication and public engagement efforts. Here, we examine the use of such technologies for wildlife conservation campaigns. We obtained empirical data from four UK-based organisations through semi-structured interviews and participant observation. Visual technologies were used to provide the knowledge and generate the emotional responses perceived by organisations as being necessary for motivating a sense of caring about wildlife. We term these two aspects 'microscope' and 'spectacle', metaphorical concepts denoting the duality through which these technologies speak to both the cognitive and the emotional. As conservation relies on public support, organisations have to be seen to deliver information that is not only sufficiently detailed and scientifically credible but also spectacular enough to capture public interest. Our investigation showed that balancing science and entertainment is a difficult undertaking for wildlife-related organisations as there are perceived risks of contriving experiences of nature and obscuring conservation aims.

  13. FCJ-142 Spectacles and Tropes: Speculative Design and Contemporary Food Cultures

    Directory of Open Access Journals (Sweden)

    Carl DiSalvo

    2012-07-01

    Full Text Available Speculative design is a particularly inventive mode of design that is concerned with developing imaginative futures or alternate presents. Often, the purpose of speculative design is to prompt reflection on contemporary conditions and express possible implications of current trends in science and technology. Like all design, speculative design reproduces as well as invents culture and there are limits to the work it does. In this essay, I trace the ways speculative design reproduces contemporary food cultures through two projects: Guide to Free Farming (2009 and Family Whiskey (2010. From these projects I draw out and discuss two strategies of speculative design: the use of spectacle and the use of tropes. I describe how these strategies work to attract us to images and objects, and I identify their limits in providing content, meaning, and significance. In concluding, I consider how speculative design might enable more substantive engagement with issues.

  14. The Lost Worlds of Messmore & Damon: Science, Spectacle & Prehistoric Monsters in early-twentieth century America.

    Science.gov (United States)

    Manias, Chris

    2016-09-01

    In 1924, the model-making company Messmore & Damon, Inc. of New York unleashed their masterpiece: the Amphibious Dinosaurus Brontosaurus, a moving, breathing, roaring animatronic dinosaur, based on displays in the American Museum of Natural History. Over the 1920s and 1930s, this became the focus of an ever-increasing publicity campaign, as Messmore & Damon exhibited prehistoric automata in department stores, the media, and the Chicago World Fair of 1933-34. These displays were hugely popular and widely discussed, drawing from the increasing public appeal of paleontology. Mixing commercial entertainment with invocations of scientific value, Messmore & Damon's prehistoric creations offer a window into the meaning and popularity of the deep time sciences in early-twentieth century America, and the links between science and spectacle in this period. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. THE SPECTACLE OF REDEMPTION: GUILT AND VIOLENCE IN MARTIN SCORSESE’S RAGING BULL

    Directory of Open Access Journals (Sweden)

    Arturo Serrano

    2015-06-01

    Full Text Available Of all the characters that undertake a search for redemption in Martin Scorsese’s films, perhaps it is the story of Jake La Motta in Raging Bull that for many reasons presents the greatest challenge to understanding redemption’s role in the narratives of his films. Is Jake La Motta a redeemed character at the end of Raging Bull? I argue that Scorsese uses Raging Bull to criticize a ritualistic view of redemption by portraying the beginning of Jake’s search as a futile attempt to submit himself to a public spectacle of ritual violence in the boxing ring while visually relating this to the Catholic sacraments and the crucifixion. It will only be later—in the loneliness of a jail cell, estranged from his family and without having to have had gone through a rite—that Jake achieves the self-awareness redemption requires.

  16. Burst Into Action: The Changing Spectacle of Glamour Heroines in Contemporary Hong Kong Cinema

    Directory of Open Access Journals (Sweden)

    Stephen C. K. Chan

    2013-09-01

    Full Text Available My question for now is: in what ways have the new currents of transnationality affected existing forms of cultural sensibility in the ‘post-colony’? Realised as a system of representation of the global popular, recent articulations of popular experience tend to be absorbed into generic cross-cultural media representations shared on the glocal level of operation by cultural producers, consumers and practitioners across geographical borders. In this paper, I shall focus on the changing spectacle of ‘the local’ through its cinematic action (along with its alternative heroine mediation, in light of such a transnational articulation as the emerging dominant. My purpose is to examine how local action has been re-imagined and can be re-aligned in relation to the specifically historical, national and postcolonial mode of imagination under the contemporary glocal context of the Hong Kong ‘Special Administrative Region’ (HKSAR, as this particular post-colony is officially renamed.

  17. The Spectacle of Redemption: Guilt and Violence in Martin Scorsese’s Raging Bull

    Directory of Open Access Journals (Sweden)

    Arturo Serrano

    2015-06-01

    Full Text Available Of all the characters that undertake a search for redemption in Martin Scorsese’s films, perhaps it is the story of Jake La Motta in Raging Bull that for many reasons presents the greatest challenge to understanding redemption’s role in the narratives of his films. Is Jake La Motta a redeemed character at the end of Raging Bull? I argue that Scorsese uses Raging Bull to criticize a ritualistic view of redemption by portraying the beginning of Jake’s search as a futile attempt to submit himself to a public spectacle of ritual violence in the boxing ring while visually relating this to the Catholic sacraments and the crucifixion. It will only be later—in the loneliness of a jail cell, estranged from his family and without having to have had gone through a rite—that Jake achieves the self-awareness redemption requires.

  18. Tolerability and Effectiveness of Contact Lenses in Mild Traumatic Brain Injury with Visual Discomfort: A Case Series

    Directory of Open Access Journals (Sweden)

    Len V. Hua, PhD

    2014-01-01

    discomfort secondary to mTBI. Traditionally, spectacles, prisms, and vision therapy have been recommended to manage mTBI visual symptoms, but our results suggest that multifocal contact lenses can also be of benefit for a subset of mTBI patients.

  19. Discovery of eight lensing clusters of galaxies

    CERN Document Server

    Liang, S M; Han, J L; Jiang, Y Y

    2013-01-01

    Clusters of galaxies have a huge mass which can act as gravitational lenses. Galaxies behind clusters can be distorted to form arcs in images by the lenses. Herein a search was done for giant lensed arcs by galaxy clusters using the SDSS data. By visually inspecting SDSS images of newly identified clusters in the SDSS DR8 and Stripe 82 data, we discover 8 strong lensing clusters together with additional 3 probable and 6 possible cases. The lensed arcs show bluer colors than the member galaxies of clusters. The masses and optical luminosities of galaxy clusters interior to the arcs are calculated, and the mass-to-light ratios are found to be in the range of a few tens of M_Solar/L_Solar, consistent with the distribution of previously known lensing clusters.

  20. Planck 2015 results. XV. Gravitational lensing

    CERN Document Server

    Ade, P A R; Arnaud, M; Ashdown, M; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Bartlett, J G; Bartolo, N; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bonaldi, A; Bonavera, L; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bucher, M; Burigana, C; Butler, R C; Calabrese, E; Cardoso, J -F; Catalano, A; Challinor, A; Chamballu, A; Chiang, H C; Christensen, P R; Church, S; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; Davis, R J; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Désert, F -X; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Ducout, A; Dunkley, J; Dupac, X; Efstathiou, G; Elsner, F; Enßlin, T A; Eriksen, H K; Fergusson, J; Finelli, F; Forni, O; Frailis, M; Fraisse, A A; Franceschi, E; Frejsel, A; Galeotta, S; Galli, S; Ganga, K; Giard, M; Giraud-Héraud, Y; Gjerløw, E; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Gudmundsson, J E; Hansen, F K; Hanson, D; Harrison, D L; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, A H; Jaffe, T R; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Kunz, M; Kurki-Suonio, H; Lagache, G; Lähteenmäki, A; Lamarre, J -M; Lasenby, A; Lattanzi, M; Lawrence, C R; Leonardi, R; Lesgourgues, J; Levrier, F; Lewis, A; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maggio, G; Maino, D; Mandolesi, N; Mangilli, A; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Mazzotta, P; McGehee, P; Meinhold, P R; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Moss, A; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; Noviello, F; Novikov, D; Novikov, I; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Pettorino, V; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Popa, L; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reach, W T; Rebolo, R; Reinecke, M; Remazeilles, M; Renault, C; Renzi, A; Ristorcelli, I; Rocha, G; Rosset, C; Rossetti, M; Roudier, G; Rowan-Robinson, M; Rubiño-Martín, J A; Rusholme, B; Sandri, M; Santos, D; Savelainen, M; Savini, G; Scott, D; Seiffert, M D; Shellard, E P S; Spencer, L D; Stolyarov, V; Stompor, R; Sudiwala, R; Sunyaev, R; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Terenzi, L; Toffolatti, L; Tomasi, M; Tristram, M; Tucci, M; Tuovinen, J; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Wade, L A; Wandelt, B D; Wehus, I K; White, M; Yvon, D; Zacchei, A; Zonca, A

    2015-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40 sigma), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator we detect lensing at a significance of 5 sigma. We cross-check the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40lensing potential power spectrum and that found in the best-fitting LCDM model based on the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percent-level measurement of ...

  1. Void Profile from Planck Lensing Potential Map

    Science.gov (United States)

    Chantavat, Teeraparb; Sawangwit, Utane; Wandelt, Benjamin D.

    2017-02-01

    We use the lensing potential map from Planck CMB lensing reconstruction analysis and the “Public Cosmic Void Catalog” to measure the stacked void lensing potential. We have made an attempt to fit the HSW void profile parameters from the stacked lensing potential. In this profile, four parameters are needed to describe the shape of voids with different characteristic radii R V . However, we have found that after reducing the background noise by subtracting the average background, there is a residue lensing power left in the data. The inclusion of the environment shifting parameter, {γ }V, is necessary to get a better fit to the data with the residue lensing power. We divide the voids into two redshift bins: cmass1 (0.45Digital Sky Survey voids reside in an underdense region.

  2. Design of spherical symmetric gradient index lenses

    Science.gov (United States)

    Miñano, Juan C.; Grabovičkić, Dejan; Benítez, Pablo; González, Juan C.; Santamaría, Asunción

    2012-10-01

    Spherical symmetric refractive index distributions also known as Gradient Index lenses such as the Maxwell-Fish-Eye (MFE), the Luneburg or the Eaton lenses have always played an important role in Optics. The recent development of the technique called Transformation Optics has renewed the interest in these gradient index lenses. For instance, Perfect Imaging within the Wave Optics framework has recently been proved using the MFE distribution. We review here the design problem of these lenses, classify them in two groups (Luneburg moveable-limits and fixed-limits type), and establish a new design techniques for each type of problem.

  3. Ion exchange tempering of glass ophthalmic lenses.

    Science.gov (United States)

    Keeney, A H; Duerson, H L

    1975-08-01

    We performed low velocity drop-ball tests using 5/8-, 7/8-, and 1-inch diameter steel balls on ophthalmic crown glass lenses chemically tempered by the ion exchange process. Four representative dioptric strengths (+ 2.50 spherical, - 2.50 spherical, -2.50 cylindrical, and plano) were studied with the isolated lenses mounted, convex side up, on the American National Standards Institute Z80 test block. New ion exchange lenses exhibited a 100 to 350% greater capacity for attenuation of energy from low velocity, large size missiles than matched lenses of similar strength prepared by the conventional heat-treating and air-quenching process.

  4. Plastic bronchitis

    National Research Council Canada - National Science Library

    Singhi, Anil Kumar; Vinoth, Bharathi; Kuruvilla, Sarah; Sivakumar, Kothandam

    2015-01-01

    Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics...

  5. Plastic Fishes

    CERN Multimedia

    Trettnak, Wolfgang

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness. The slideshow below gives you a taste of the artworks by Wolfgang Trettnak and Margarita Cimadevila.

  6. Plastic Bridge

    Institute of Scientific and Technical Information of China (English)

    履之

    1994-01-01

    Already ubiquitous in homes and cars, plastic is now appearing inbridges. An academic-industrial consortium based at the University ofCalifornia in San Diego is launching a three-year research program aimed atdeveloping the world’s first plastic highway bridge, a 450-foot span madeentirely from glass-,carbon,and polymer-fiber-reinforced composite mate-rials, the stuff of military aircraft. It will cross Interstate 5 to connect thetwo sides of the school’s campus.

  7. GREEN PLASTIC: A NEW PLASTIC FOR PACKAGING

    OpenAIRE

    Mr. Pankaj Kumar*, Sonia

    2016-01-01

    This paper gives a brief idea about a new type of plastic called as bio-plastic or green plastic. Plastic is used as a packaging material for various products, but this plastic is made up of non renewable raw materials. There are various disadvantages of using conventional plastic like littering, CO2 production, non-degradable in nature etc. To overcome these problems a new type of plastic is discovered called bio-plastic or green plastic. Bio-plastic is made from renewable resources and also...

  8. N-body lensed CMB maps: lensing extraction and characterization

    CERN Document Server

    Antolini, Claudia; Martinelli, Matteo; Carbone, Carmelita; Baccigalupi, Carlo

    2013-01-01

    We reconstruct shear maps and angular power spectra from simulated weakly lensed total intensity (TT) and polarised (EB) maps of the Cosmic Microwave Background (CMB) anisotropies, obtained using Born approximated ray-tracing through the N-body simulated Cold Dark Matter (CDM) structures in the Millennium Simulations (MS). We compare the recovered signal with the ${\\Lambda}$CDM prediction, on the whole interval of angular scales which is allowed by the finite box size, extending from the degree scale to the arcminute, by applying a quadratic estimator in the flat sky limit; we consider PRISM-like instrumental specification for future generation CMB satellites, corresponding to arcminute angular resolution of 3.2' and sensitivity of 2.43 ${\\mu}$K-arcmin. The noise bias in the simulations closely follows the estimator prediction, becoming dominated by limits in the angular resolution for the EB signal, at l ${\\simeq}$ 1500. The de-biased signal shows no visible departure from predictions of the weak lensing pow...

  9. The Scales of Gravitational Lensing

    CERN Document Server

    De Paolis, Francesco; Ingrosso, Gabriele; Manni, Luigi; Nucita, Achille; Strafella, Francesco

    2016-01-01

    After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge) of supermassive black holes in the center of ours and nearby galaxies.

  10. The Scales of Gravitational Lensing

    Directory of Open Access Journals (Sweden)

    Francesco De Paolis

    2016-03-01

    Full Text Available After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge of supermassive black holes in the center of ours and nearby galaxies.

  11. Natural wormholes as gravitational lenses

    CERN Document Server

    Cramer, J G; Morris, M S; Visser, M; Benford, G; Landis, G A; Cramer, John G; Forward, Robert L; Morris, Michael S; Visser, Matt; Benford, Gregory; Landis, Geoffrey A

    1995-01-01

    Visser has suggested traversable 3-dimensional wormholes that could plausibly form naturally during Big Bang inflation. A wormhole mouth embedded in high mass density might accrete mass, giving the other mouth a net *negative* mass of unusual gravitational properties. The lensing of such a gravitationally negative anomalous compact halo object (GNACHO) will enhance background stars with a time profile that is observable and qualitatively different from that recently observed for massive compact halo objects (MACHOs) of positive mass. We recommend that MACHO search data be analyzed for GNACHOs.

  12. Ocular Straylight with Different Multifocal Contact Lenses

    NARCIS (Netherlands)

    Łabuz, Grzegorz; López-Gil, Norberto; van den Berg, Thomas J T P; Vargas-Martín, Fernando

    2017-01-01

    PURPOSE: Multifocal contact lenses have been growing in popularity as a modality to correct presbyopic eyes, although visual side effects such as disability glare have been reported. The objective of this study was to investigate the effect of multifocal contact lenses on disability glare by means

  13. Modern scleral lenses part I: clinical features.

    NARCIS (Netherlands)

    Visser, E.S.; Visser, R.; Lier, H.J.J. van; Otten, H.M.

    2007-01-01

    PURPOSE: To evaluate the indications for modern scleral lenses and their clinical performance in patients who were fitted with scleral lenses at the authors' practices. METHODS: In this cross-sectional survey, all the necessary data were obtained at the first follow-up visit during the 5-month study

  14. Planck 2015 results: XV. Gravitational lensing

    DEFF Research Database (Denmark)

    Ade, P. A R; Aghanim, N.; Arnaud, M.;

    2016-01-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40σ), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator, we detect lensing at a significance of 5σ. We...

  15. Optical aberrations in a gas lenses

    CSIR Research Space (South Africa)

    Mafusire, C

    2010-08-01

    Full Text Available and Security Presented at the Laser Beam Shaping XI, 2010 SPIE Optics + Photonics Annual Conference San Diego Convention Centre San Diego, California 1-5 August 2010 Page 2 © CSIR 2010 www.csir.co.za Gas Lenses • Gas Lenses and M...

  16. A comparison of the effect of reduced illumination and tinted lenses on stereospsis at near

    Directory of Open Access Journals (Sweden)

    M. Mehta

    2007-01-01

    Full Text Available Relative depth may be appreciated with the use of one eye using linear perspective, shadows, parallax and texture as monocular cues to depth. Stereopsis, on the other hand, is the directappreciation of relative depth that requires the use of both eyes to construct a three-dimension-al percept from disparate two-dimensional retinal images. The advantage of stereopsis is with respect to complex visual tasks especially that requiring accurate hand-eye coordination. Tinted lenses are prescribed for a variety of reasons, including but not limited to photophobia, asthenopia, improving colour perception in colour deficient individuals, enhancing cosmesis and protection against glare or harmful radiation and enhancing visual performance as in sports. The aim of this study was to investigate the comparative effects of six specific CR39 tinted spectacle lenses (grade B, and a white CR39 lens, against a no lens condition, on stereoacuity over a range of illumination levels. Illumination was varied with the use of neutral density (ND filters, while the Titmus Fly Stereotest (TFS wasused to measure stereoacuity. Participants (n =60 between the ages of 17 - 29 years (mean =23.58; sd = 3.14 were purposively sampled from a clinical practice to participate in this research study.  Using repeated measures ANOVA and appropriate post-hoc multivariate analysis, it was evident that there was a significant decline in stereopsis as the level ofillumination decreased,regardless of tint condition; also there was no statistically significant difference in stereopsis between the no lens and white lens conditions at each level of illumination; and stereopsis wassignificantly superior with the no lens conditioncompared to all six other tint conditions (gradeB, at each level of illumination. These results indicate that stereoacuity, as measured by the TFS, is adversely affected by adecline in retinal illuminance and by the use of tinted lenses. This information could

  17. Are flying-foxes coming to town? Urbanisation of the spectacled flying-fox (Pteropus conspicillatus in Australia.

    Directory of Open Access Journals (Sweden)

    Jessica Tait

    Full Text Available Urbanisation of wildlife populations is a process with significant conservation and management implications. While urban areas can provide habitat for wildlife, some urbanised species eventually come into conflict with humans. Understanding the process and drivers of wildlife urbanisation is fundamental to developing effective management responses to this phenomenon. In Australia, flying-foxes (Pteropodidae are a common feature of urban environments, sometimes roosting in groups of tens of thousands of individuals. Flying-foxes appear to be becoming increasingly urbanised and are coming into increased contact and conflict with humans. Flying-fox management is now a highly contentious issue. In this study we used monitoring data collected over a 15 year period (1998-2012 to examine the spatial and temporal patterns of association of spectacled flying-fox (Pteropus conspicillatus roost sites (camps with urban areas. We asked whether spectacled flying-foxes are becoming more urbanised and test the hypothesis that such changes are associated with anthropogenic changes to landscape structure. Our results indicate that spectacled flying-foxes were more likely to roost near humans than might be expected by chance, that over the period of the study the proportion of the flying-foxes in urban-associated camps increased, as did the number of urban camps. Increased urbanisation of spectacled flying-foxes was not related to changes in landscape structure or to the encroachment of urban areas on camps. Overall, camps tended to be found in areas that were more fragmented, closer to human habitation and with more urban land cover than the surrounding landscape. This suggests that urbanisation is a behavioural response rather than driven by habitat loss.

  18. Geometry of weak lensing of CMB polarization

    CERN Document Server

    Challinor, A D; Challinor, Anthony; Chon, Gayoung

    2002-01-01

    Hu has presented a harmonic-space method for calculating the effects of weak gravitational lensing on the cosmic microwave background (CMB) over the full sky. Computing the lensed power spectra to first order in the deflection power requires one to formulate the lensing displacement beyond the tangent-space approximation. We point out that for CMB polarization this displacement must undergo geometric corrections on the spherical sky to maintain statistical isotropy of the lensed fields. Although not discussed by Hu, these geometric effects are implicit in his analysis. However, there they are hidden by an overly-compact notation that is both unconventional and rather confusing. Here we aim to ameliorate this deficiency by providing a rigorous derivation of the lensed spherical power spectra.

  19. Gravitational Lensing of Cosmic Microwave Background Polarization

    CERN Document Server

    Ade, P A R; Anthony, A E; Arnold, K; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Dobbs, M; Elleflot, T; Errard, J; Fabbian, G; Feng, C; Flanigan, D; Gilbert, A; Grainger, W; Halverson, N W; Hasegawa, M; Hattori, K; Hazumi, M; Holzapfel, W L; Hori, Y; Howard, J; Hyland, P; Inoue, Y; Jaehnig, G C; Jaffe, A; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Jeune, M Le; Lee, A T; Linder, E; Lungu, M; Matsuda, F; Matsumura, T; Meng, X; Miller, N J; Morii, H; Moyerman, S; Myers, M J; Navaroli, M; Nishino, H; Paar, H; Peloton, J; Quealy, E; Rebeiz, G; Reichardt, C L; Richards, P L; Ross, C; Schanning, I; Schenck, D E; Sherwin, B; Shimizu, A; Shimmin, C; Shimon, M; Siritanasak, P; Smecher, G; Spieler, H; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Takakura, S; Tomaru, T; Wilson, B; Yadav, A; Zahn, O

    2013-01-01

    Primary fluctuations in both temperature and polarization of the Cosmic Microwave Background (CMB) reflect the properties of the Universe from the Big Bang until the photons decoupled from matter 380,000 years later. These primary fluctuations are then lensed by large-scale structures (such as clusters of galaxies and filaments of dark matter), with the result that the distribution and properties of dark matter, including the masses of neutrinos, can be determined more accurately by extracting the lensing information than through studying the primary fluctuations alone. Polarization lensing can give cleaner, higher resolution results than temperature lensing. The correlation of lensed CMB polarization with large-scale structure, traced through the Cosmic Infrared Background, was recently detected; however, this correlation does not trace all structure and depends on the relationship between the infrared flux from the galaxies and the underlying mass distribution. Here we report the detection of gravitational ...

  20. On aberration in gravitational lensing

    CERN Document Server

    Sereno, M

    2008-01-01

    It is known that a relative translational motion between the deflector and the observer affects gravitational lensing. In this paper, a lens equation is obtained to describe such effects on actual lensing observables. Results can be easily interpreted in terms of aberration of light-rays. Both radial and transverse motions with relativistic velocities are considered. The lens equation is derived by first considering geodesic motion of photons in the rest-frame Schwarzschild spacetime of the lens, and, then, light-ray detection in the moving observer's frame. Due to the transverse motion images are displaced and distorted in the observer's celestial sphere, whereas the radial velocity along the line of sight causes an effective re-scaling of the lens mass. The Einstein ring is distorted to an ellipse whereas the caustics in the source plane are still point-like. Either for null transverse motion or up to linear order in velocities, the critical curve is still a circle with its radius corrected by a factor (1+z...

  1. Ray optics of generalized lenses.

    Science.gov (United States)

    Chaplain, Gregory J; Macauley, Gavin; Bělín, Jakub; Tyc, Tomáš; Cowie, Euan N; Courtial, Johannes

    2016-05-01

    We study the ray optics of generalized lenses (glenses), which are ideal thin lenses generalized to have different object- and image-sided focal lengths, and the most general light-ray-direction-changing surfaces that stigmatically image any point in object space to a corresponding point in image space. Gabor superlenses [UK patent541,753 (1940); J. Opt. A1, 94 (1999)JOAOF81464-425810.1088/1464-4258/1/1/013] can be seen as pixelated realizations of glenses. Our analysis is centered on the nodal point. Whereas the nodal point of a thin lens always resides in the lens plane, that of a glens can reside anywhere on the optical axis. Utilizing the nodal point, we derive simple equations that describe the mapping between object and image space and the light-ray-direction change. We demonstrate our findings with the help of ray-tracing simulations. Glenses allow novel optical instruments to be realized, at least theoretically, and our results facilitate the design and analysis of such devices.

  2. Developments in Accommodating Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Zeki Tunç

    2012-07-01

    Full Text Available Technical progress in cataract surgery has decreased the incidence of severe complications in this type of surgery. The introduction of micro incision cataract surgery (MICS (sub- 2.0 mm incision allow the surgeon to achieve better postoperative control of astigmatism and higherorder aberration (HOAs with minimum induction of both. It is believed that multifocal lenses provide very successful results, however, there are limitations to these. Implantation of accommodating intraocular lenses (IOLs is an option to treat presbyopia. The IOLs work by using the continued functionality of the ciliary muscle after cataract removal. Accommodating IOLs were designed to avoid the optical side effects of multifocal IOLs. Two main design concepts exist. First, axial shift concepts rely on anterior axial movement of one or two optics creating accommodative ability. Second, curvature change designs are designed to provide significant amplitudes of accommodation with little physical displacement. Accommodative IOLs to correct astigmatism and HOAs in the future are needed. (Turk J Ophthalmol 2012; 42: 288-93

  3. Cosmology with Strong Lensing Systems

    CERN Document Server

    Cao, Shuo; Gavazzi, Raphaël; Piórkowska, Aleksandra; Zhu, Zong-Hong

    2015-01-01

    In this paper, we assemble a catalog of 118 strong gravitational lensing systems from SLACS, BELLS, LSD and SL2S surveys and use them to constrain the cosmic equation of state. In particular we consider two cases of dark energy phenomenology: $XCDM$ model where dark energy is modeled by a fluid with constant $w$ equation of state parameter and in Chevalier - Polarski - Linder (CPL) parametrization where $w$ is allowed to evolve with redshift: $w(z) = w_0 + w_1 \\frac{z}{1+z}$. We assume spherically symmetric mass distribution in lensing galaxies, but relax the rigid assumption of SIS model in favor to more general power-law index $\\gamma$, also allowing it to evolve with redshifts $\\gamma(z)$. Our results for the $XCDM$ cosmology show the agreement with values (concerning both $w$ and $\\gamma$ parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with $\\gamma(z)$. The resulting confidence regions for the parameters are much better than those obtained with a similar metho...

  4. The Search for Lensed Supernovae

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    Type Ia supernovae that have multiple images due to gravitational lensing can provide us with a wealth of information both about the supernovae themselves and about our surrounding universe. But how can we find these rare explosions?Clues from Multiple ImagesWhen light from a distant object passes by a massive foreground galaxy, the galaxys strong gravitational pull can bend the light, distorting our view of the backgroundobject. In severe cases, this process can cause multiple images of the distant object to appear in the foreground lensing galaxy.An illustration of gravitational lensing. Light from the distant supernova is bent as it passes through a giant elliptical galaxy in the foreground, causing multiple images of the supernova to appear to be hosted by the elliptical galaxy. [Adapted from image by NASA/ESA/A. Feild (STScI)]Observations of multiply-imaged Type Ia supernovae (explosions that occur when white dwarfs in binary systems exceed their maximum allowed mass) could answer a number of astronomical questions. Because Type Ia supernovae are standard candles, distant, lensed Type Ia supernovae can be used to extend the Hubble diagram to high redshifts. Furthermore, the lensing time delays from the multiply-imaged explosion can provide high-precision constraints on cosmological parameters.The catch? So far, weve only found one multiply-imaged Type Ia supernova: iPTF16geu, discovered late last year. Were going to need a lot more of them to develop a useful sample! So how do we identify themutiply-imaged Type Ias among the many billions of fleeting events discovered in current and future surveys of transients?Searching for AnomaliesAbsolute magnitudes for Type Ia supernovae in elliptical galaxies. None are expected to be above -20 in the B band, so if we calculate a magnitude for a Type Ia supernova thats larger than this, its probably not hosted by the galaxy we think it is! [Goldstein Nugent 2017]Two scientists from University of California, Berkeley and

  5. Visual outcomes after spectacles treatment in children with bilateral high refractive amblyopia.

    Science.gov (United States)

    Lin, Pei-Wen; Chang, Hsueh-Wen; Lai, Ing-Chou; Teng, Mei-Ching

    2016-11-01

    The aim was to investigate the visual outcomes of treatment with spectacles for bilateral high refractive amblyopia in children three to eight years of age. Children with previously untreated bilateral refractive amblyopia were enrolled. Bilateral high refractive amblyopia was defined as visual acuity (VA) being worse than 6/9 in both eyes in the presence of 5.00 D or more of hyperopia, 5.00 D or more of myopia and 2.00 D or more of astigmatism. Full myopic and astigmatic refractive errors were corrected, and the hyperopic refractive errors were corrected within 1.00 D of the full correction. All children received visual assessments at four-weekly intervals. VA, Worth four-dot test and Randot preschool stereotest were assessed at baseline and every four weeks for two years. Twenty-eight children with previously untreated bilateral high refractive amblyopia were enrolled. The mean VA at baseline was 0.39 ± 0.24 logMAR and it significantly improved to 0.21, 0.14, 0.11, 0.05 and 0.0 logMAR at four, eight, 12, 24 weeks and 18 months, respectively (all p = 0.001). The mean stereoacuity (SA) was 1,143 ± 617 arcsec at baseline and it significantly improved to 701, 532, 429, 211 and 98 arcsec at four, eight, 12, 24 weeks and 18 months, respectively (all p = 0.001). The time interval for VA achieving 6/6 was significantly shorter in the eyes of low spherical equivalent (SE) (-2.00 D +2.00 D) (3.33 ± 2.75 months versus 8.11 ± 4.56 months, p = 0.0005). All subjects had normal fusion on Worth four-dot test at baseline and all follow-up visits. Refractive correction with good spectacles compliance improves VA and SA in young children with bilateral high refractive amblyopia. Patients with greater amounts of refractive error will achieve resolution of amblyopia with a longer time. © 2016 Optometry Australia.

  6. Patients' satisfaction and spectacle independence after cataract surgery with multifocal intraocular lens implantation in a tertiary care hospital.

    Science.gov (United States)

    Baig, Rashid; A Chaudhry, Tanveer; Kukreja, Saajan; Shakil, Sidra; Ahmad, Khabir

    2016-06-01

    This single group cohort study, undertaken at Aga Khan University Hospital, Karachi, from Jan 2012 to September 2013, assessed patients' satisfaction, spectacle independence and visual disturbance after implantation of multifocal IOLs. A total of 39 patients who underwent bilateral cataract surgery with multifocal IOL implantation were included for telephonic interviews. The mean age of participants was 55.5 ± 8.1 years. The mean follow up time was 9.60 ± 3.19 months. The overall satisfaction rate after surgery was found to be 84.6% and there was no statistically significant association of satisfaction with gender, age or education. In all 84.6%, 94.9% and 84.6% people had spectacle independence for far, intermediate and near, respectively. More than half of participants (59%) had some degree of visual disturbance. In this study, multifocal IOL implantation provided high levels of satisfaction and spectacle independence despite notable risk of halo or glare symptoms at night. Therefore, careful patient selection and preoperative counselling regarding possible risks and benefits is recommended.

  7. Plastic condoms.

    Science.gov (United States)

    1968-01-01

    Only simple equipment, simple technology and low initial capital investment are needed in their manufacture. The condoms can be made by people who were previously unskilled or only semi-skilled workers. Plastic condoms differ from those made of latex rubber in that the nature of the plastic film allows unlimited shelf-life. Also, the plastic has a higher degree of lubricity than latex rubber; if there is a demand for extra lubrication in a particular market, this can be provided. Because the plastic is inert, these condoms need not be packaged in hermetically sealed containers. All these attributes make it possible to put these condoms on the distributors' shelves in developing countries competitively with rubber condoms. The shape of the plastic condom is based on that of the lamb caecum, which has long been used as luxury-type condom. The plastic condom is made from plastic film (ethylene ethyl acrilate) of 0.001 inch (0.0254 mm.) thickness. In addition, a rubber ring is provided and sealed into the base of the condom for retention during coitus. The advantage of the plastic condom design and the equipment on which it is made is that production can be carried out either in labour-intensive economy or with varying degrees of mechanization and automation. The uniform, finished condom if made using previously untrained workers. Training of workers can be done in a matter of hours on the two machines which are needed to produce and test the condoms. The plastic film is provided on a double wound roll, and condom blanks are prepared by means of a heat-sealing die on the stamping machine. The rubber rings are united to the condom blanks on an assembly machine, which consists of a mandrel and heat-sealing equipment to seal the rubber ring to the base of the condom. Built into the assembly machine is a simple air-testing apparatus that can detect the smallest pinhole flaw in a condom. The manufacturing process is completed by unravelling the condom from the assembly

  8. Planck 2015 results. XV. Gravitational lensing

    Science.gov (United States)

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Arnaud, M.; Ashdown, M.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Bartlett, J. G.; Bartolo, N.; Basak, S.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J.-P.; Bersanelli, M.; Bielewicz, P.; Bock, J. J.; Bonaldi, A.; Bonavera, L.; Bond, J. R.; Borrill, J.; Bouchet, F. R.; Boulanger, F.; Bucher, M.; Burigana, C.; Butler, R. C.; Calabrese, E.; Cardoso, J.-F.; Catalano, A.; Challinor, A.; Chamballu, A.; Chiang, H. C.; Christensen, P. R.; Church, S.; Clements, D. L.; Colombi, S.; Colombo, L. P. L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B. P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R. D.; Davis, R. J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Désert, F.-X.; Diego, J. M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Ducout, A.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Elsner, F.; Enßlin, T. A.; Eriksen, H. K.; Fergusson, J.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A. A.; Franceschi, E.; Frejsel, A.; Galeotta, S.; Galli, S.; Ganga, K.; Giard, M.; Giraud-Héraud, Y.; Gjerløw, E.; González-Nuevo, J.; Górski, K. M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J. E.; Hansen, F. K.; Hanson, D.; Harrison, D. L.; Henrot-Versillé, S.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S. R.; Hivon, E.; Hobson, M.; Holmes, W. A.; Hornstrup, A.; Hovest, W.; Huffenberger, K. M.; Hurier, G.; Jaffe, A. H.; Jaffe, T. R.; Jones, W. C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T. S.; Kneissl, R.; Knoche, J.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lähteenmäki, A.; Lamarre, J.-M.; Lasenby, A.; Lattanzi, M.; Lawrence, C. R.; Leonardi, R.; Lesgourgues, J.; Levrier, F.; Lewis, A.; Liguori, M.; Lilje, P. B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P. M.; Macías-Pérez, J. F.; Maggio, G.; Maino, D.; Mandolesi, N.; Mangilli, A.; Maris, M.; Martin, P. G.; Martínez-González, E.; Masi, S.; Matarrese, S.; McGehee, P.; Meinhold, P. R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M.-A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Moss, A.; Munshi, D.; Murphy, J. A.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C. B.; Nørgaard-Nielsen, H. U.; Noviello, F.; Novikov, D.; Novikov, I.; Oxborrow, C. A.; Paci, F.; Pagano, L.; Pajot, F.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Pettorino, V.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Popa, L.; Pratt, G. W.; Prézeau, G.; Prunet, S.; Puget, J.-L.; Rachen, J. P.; Reach, W. T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Renzi, A.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Rossetti, M.; Roudier, G.; Rowan-Robinson, M.; Rubiño-Martín, J. A.; Rusholme, B.; Sandri, M.; Santos, D.; Savelainen, M.; Savini, G.; Scott, D.; Seiffert, M. D.; Shellard, E. P. S.; Spencer, L. D.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sunyaev, R.; Sutton, D.; Suur-Uski, A.-S.; Sygnet, J.-F.; Tauber, J. A.; Terenzi, L.; Toffolatti, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Tuovinen, J.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vielva, P.; Villa, F.; Wade, L. A.; Wandelt, B. D.; Wehus, I. K.; White, M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2016-09-01

    We present the most significant measurement of the cosmic microwave background (CMB) lensing potential to date (at a level of 40σ), using temperature and polarization data from the Planck 2015 full-mission release. Using a polarization-only estimator, we detect lensing at a significance of 5σ. We cross-check the accuracy of our measurement using the wide frequency coverage and complementarity of the temperature and polarization measurements. Public products based on this measurement include an estimate of the lensing potential over approximately 70% of the sky, an estimate of the lensing potential power spectrum in bandpowers for the multipole range 40 ≤ L ≤ 400, and an associated likelihood for cosmological parameter constraints. We find good agreement between our measurement of the lensing potential power spectrum and that found in the ΛCDM model that best fits the Planck temperature and polarization power spectra. Using the lensing likelihood alone we obtain a percent-level measurement of the parameter combination σ8Ω0.25m = 0.591 ± 0.021. We combine our determination of the lensing potential with the E-mode polarization, also measured by Planck, to generate an estimate of the lensing B-mode. We show that this lensing B-mode estimate is correlated with the B-modes observed directly by Planck at the expected level and with a statistical significance of 10σ, confirming Planck's sensitivity to this known sky signal. We also correlate our lensing potential estimate with the large-scale temperature anisotropies, detecting a cross-correlation at the 3σ level, as expected because of dark energy in the concordance ΛCDM model.

  9. Plastic Bronchitis.

    Science.gov (United States)

    Rubin, Bruce K

    2016-09-01

    Plastic bronchitis is an uncommon and probably underrecognized disorder, diagnosed by the expectoration or bronchoscopic removal of firm, cohesive, branching casts. It should not be confused with purulent mucous plugging of the airway as seen in patients with cystic fibrosis or bronchiectasis. Few medications have been shown to be effective and some are now recognized as potentially harmful. Current research directions in plastic bronchitis research include understanding the genetics of lymphatic development and maldevelopment, determining how abnormal lymphatic malformations contribute to cast formation, and developing new treatments. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Design and development of a laminated glass-plastic Fresnel lens for point focus photovoltaic systems

    Energy Technology Data Exchange (ETDEWEB)

    Matalon, L. A.

    1982-08-01

    The design and development of a laminated glass-plastic Fresnel lens for point focus photovoltaic systems use is described. The objective of this development was to examine the feasibility of producing lenses with a cost effectiveness superior to that of lenses made by casting of acrylic. The procedure used in executing this development, the method used in cost effectiveness evaluation, results obtained and recommendations for further work are presented.

  11. Spectacle independence and subjective satisfaction of ReSTOR® multifocal intraocular lens after cataract or presbyopia surgery in two European countries

    Directory of Open Access Journals (Sweden)

    Béatrice Cochener

    2010-02-01

    Full Text Available Béatrice Cochener1, Luis Fernández-Vega2, Jose F Alfonso2, Frédérique Maurel3, Juliette Meunier4, Gilles Berdeaux5,61Centre Hospitalier de Brest, Brest, France; 2Instituto Oftalmologico Fernandez Vega, Oviedo, Spain; 3IMS Health, Health Economics Department, Puteaux, France; 4Mapi Values, Lyon, France; 5Alcon France, Health Economics Department, Rueil-Malmaison, France; 6Conservatoire National des Arts et Métiers, Paris, FrancePurpose: To determine the percentage of patients implanted bilaterally with ReSTOR® requiring spectacles at 18 months, the patient satisfaction, and factors that predict spectacles independence.Methods: The medical and surgical data were collected from patient records. The ‘Freedom from Spectacles Value Scale’ (FGVS was used to rank their experiences via telephone interview. A Bayesian network was used to predict postoperative spectacles use.Results: 304 patients (65.6 years were included. Postoperative visual acuity was ≥0.8 in 93.3% of patients for near vision and in 88.6% of patients for distance vision. After surgery, 87.2% of the patients were spectacles free. 88.2% of the patients rated their vision as being better following the surgery and 93.1% thought that surgery resulted in a positive change. FGVS mean scores (5 the most favorable rating were: ‘Practical Advantages’ 3.8, ‘Psychological Advantages’ 3.8, ‘Evaluation of the Result’ 4.5, ‘Feelings’ 4.4, and ‘Global Judgement’ 4.4. Patients who stated that spectacles wear was particularly bothersome and those who thought that their appearance was more favorable without spectacles were 3 times more likely not to wear spectacles postoperatively.Conclusion: ReSTOR® provides patients with good distance and near vision, a high rate of spectacles independence, and a high degree of patient satisfaction.Keywords: cataract surgery, multifocal intraocular lens, patient satisfaction, spectacles independence

  12. Mixed plastics recycling technology

    CERN Document Server

    Hegberg, Bruce

    1995-01-01

    Presents an overview of mixed plastics recycling technology. In addition, it characterizes mixed plastics wastes and describes collection methods, costs, and markets for reprocessed plastics products.

  13. Granulomatous encephalomyelitis and intestinal ganglionitis in a spectacled Amazon parrot (Amazona albifrons) infected with Mycobacterium genavense.

    Science.gov (United States)

    Gomez, G; Saggese, M D; Weeks, B R; Hoppes, S M; Porter, B F

    2011-01-01

    An approximately 30-year-old male spectacled Amazon parrot (Amazona albifrons) was presented with a 2-week history of ataxia, head shaking, weight loss and seizures. Gross findings on necropsy examination included atrophy of the musculature, ruffled feathers and minimal epicardial and abdominal fat. Microscopically, there were perivascular cuffs of macrophages with fewer lymphocytes in the grey and white matter of the brain and spinal cord. These lesions were accompanied by gliosis and mild vacuolation of the white matter. In the small intestine, up to 70% of the intestinal ganglia were effaced by infiltrates of macrophages and fewer lymphocytes. The intestinal lamina propria contained multiple inflammatory aggregates of a similar nature. Ziehl-Neelsen staining revealed the presence of numerous bacilli within the cytoplasm of macrophages in the central nervous system (CNS) and enteric ganglia. Amplification of the DNAJ gene confirmed a mycobacterial infection and subsequent polymerase chain reaction (PCR) using a species-specific primer confirmed the aetiology as Mycobacterium genavense. Infection of the CNS with Mycobacterium spp. is uncommon and has not been previously reported in a parrot. This case is unusual in that the organism exhibited tropism for neural tissue.

  14. Scanning Miniature Microscopes without Lenses

    Science.gov (United States)

    Wang, Yu

    2009-01-01

    The figure schematically depicts some alternative designs of proposed compact, lightweight optoelectronic microscopes that would contain no lenses and would generate magnified video images of specimens. Microscopes of this type were described previously in Miniature Microscope Without Lenses (NPO - 20218), NASA Tech Briefs, Vol. 22, No. 8 (August 1998), page 43 and Reflective Variants of Miniature Microscope Without Lenses (NPO 20610), NASA Tech Briefs, Vol. 26, No. 9 (September 1999), page 6a. To recapitulate: In the design and construction of a microscope of this type, the focusing optics of a conventional microscope are replaced by a combination of a microchannel filter and a charge-coupled-device (CCD) image detector. Elimination of focusing optics reduces the size and weight of the instrument and eliminates the need for the time-consuming focusing operation. The microscopes described in the cited prior articles contained two-dimensional CCDs registered with two-dimensional arrays of microchannels and, as such, were designed to produce full two-dimensional images, without need for scanning. The microscopes of the present proposal would contain one-dimensional (line image) CCDs registered with linear arrays of microchannels. In the operation of such a microscope, one would scan a specimen along a line perpendicular to the array axis (in other words, one would scan in pushbroom fashion). One could then synthesize a full two-dimensional image of the specimen from the line-image data acquired at one-pixel increments of position along the scan. In one of the proposed microscopes, a beam of unpolarized light for illuminating the specimen would enter from the side. This light would be reflected down onto the specimen by a nonpolarizing beam splitter attached to the microchannels at their lower ends. A portion of the light incident on the specimen would be reflected upward, through the beam splitter and along the microchannels, to form an image on the CCD. If the

  15. Plastic fish

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In terms of weight, the plastic pollution in the world’s oceans is estimated to be around 300,000 tonnes. This plastic comes from both land-based and ocean-based sources. A lecture at CERN by chemist Wolfgang Trettnak addressed this issue and highlighted the role of art in raising people’s awareness.   Artwork by Wolfgang Trettnak. Packaging materials, consumer goods (shoes, kids’ toys, etc.), leftovers from fishing and aquaculture activities… our oceans and beaches are full of plastic litter. Most of the debris from beaches is plastic bottles. “PET bottles have high durability and stability,” explains Wolfgang Trettnak, a chemist by education and artist from Austria, who gave a lecture on this topic organised by the Staff Association at CERN on 26 May. “PET degrades very slowly and the estimated lifetime of a bottle is 450 years.” In addition to the beach litter accumulated from human use, rivers bring several ki...

  16. Plastic zonnecellen

    NARCIS (Netherlands)

    Roggen, Marjolein

    1998-01-01

    De zonnecel van de toekomst is in de maak. Onderzoekers van uiteenlopend pluimage werken eendrachtig aan een plastic zonnecel. De basis is technisch gelegd met een optimale, door invallend licht veroorzaakte, vorming van ladingdragers binnen een composiet van polymeren en buckyballs. Nu is het zaak

  17. Possible association between corneal infections and contact lenses wearing to correct ametropia in children

    Directory of Open Access Journals (Sweden)

    E. Yu. Markova

    2014-01-01

    Full Text Available Possible association between corneal infections and contact lenses (CLs wearing of various design to correct ametropia in children was analyzed. Between 2011 and April 2014, 20 children (7 boys, 13 girls aged 9‑17 years which were diagnosed with traumatic keratitis were admitted to Morozov Children’s Hospital. All patients used CLs (rigid, n = 1; soft, n = 9; orthokeratology, n = 10 to correct ametropia for 6‑48 months. There are pretty strong evidences that CLs (including orthokeratology ones provide better quality of vision and life as compared with spectacles, reduce myopia progression, and promote better accommodation. However, in spite of these advantages, CLs have disadvantages as well. People who wear CLs may require frequent eye care specialist follow-up due to the higher risk of corneal disorders. Even nearly perfect CL represents a foreign body (especially for a children eye that may provoke numerous complications including severe ones. With accurate fitting, proper care, and careful monitoring of the cornea, CLs should be safe and effective.

  18. Possible association between corneal infections and contact lenses wearing to correct ametropia in children

    Directory of Open Access Journals (Sweden)

    E. Yu. Markova

    2014-10-01

    Full Text Available Possible association between corneal infections and contact lenses (CLs wearing of various design to correct ametropia in children was analyzed. Between 2011 and April 2014, 20 children (7 boys, 13 girls aged 9‑17 years which were diagnosed with traumatic keratitis were admitted to Morozov Children’s Hospital. All patients used CLs (rigid, n = 1; soft, n = 9; orthokeratology, n = 10 to correct ametropia for 6‑48 months. There are pretty strong evidences that CLs (including orthokeratology ones provide better quality of vision and life as compared with spectacles, reduce myopia progression, and promote better accommodation. However, in spite of these advantages, CLs have disadvantages as well. People who wear CLs may require frequent eye care specialist follow-up due to the higher risk of corneal disorders. Even nearly perfect CL represents a foreign body (especially for a children eye that may provoke numerous complications including severe ones. With accurate fitting, proper care, and careful monitoring of the cornea, CLs should be safe and effective.

  19. Investigations of Galaxy Clusters Using Gravitational Lensing

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, Matthew P. [Northern Illinois Univ., DeKalb, IL (United States)

    2014-08-01

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  20. Tailoring strong lensing cosmographic observations

    Science.gov (United States)

    Linder, Eric V.

    2015-04-01

    Strong lensing time delay cosmography has excellent complementarity with other dark energy probes and will soon have abundant systems detected. We investigate two issues in the imaging and spectroscopic follow-up required to obtain the time delay distance. The first is optimization of spectroscopic resources. We develop a code to optimize the cosmological leverage under the constraint of constant spectroscopic time and find that sculpting the lens system redshift distribution can deliver a 40% improvement in dark energy figure of merit. The second is the role of systematics, correlated between different quantities of a given system or model errors common to all systems. We show how the levels of different systematics affect the cosmological parameter estimation and derive guidance for the fraction of double image vs quad image systems to follow as a function of differing systematics between them.

  1. Braneworld Black Hole Gravitational Lensing

    Science.gov (United States)

    Liang, Jun

    2017-04-01

    A class of braneworld black holes, which I called as Bronnikov-Melnikov-Dehen (BMD) black holes, are studied as gravitational lenses. I obtain the deflection angle in the strong deflection limit, and further calculate the angular positions and magnifications of relativistic images as well as the time delay between different relativistic images. I also compare the results with those obtained for Schwarzschild and two braneworld black holes, i.e., the tidal Reissner-Nordström (R-N) and the Casadio-Fabbri-Mazzacurati (CFM) black holes. Supported by Natural Science Foundation of Education Department of Shannxi Provincial Government under Grant No. 15JK1077, and Doctorial Scientific Research Starting Fund of Shannxi University of Science and Technology under Grant No. BJ12-02

  2. Adjustable fluidic lenses for ophthalmic corrections.

    Science.gov (United States)

    Marks, Randall; Mathine, David L; Peyman, Gholam; Schwiegerling, Jim; Peyghambarian, Nasser

    2009-02-15

    We report on two fluidic lenses that have been developed for ophthalmic applications. The lenses use a circular aperture to demonstrate optical powers between -20 and +20 D and a rectangular aperture to demonstrate astigmatism with values ranging from 0 to 8 D. Measurements of image quality were made with the fluidic lens using a model eye. Both lenses were variable and controllable by adjusting the fluid volume of the lens. To the best of our knowledge this is the first demonstration of a continuously variable lens for control of astigmatism.

  3. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab /SLAC /Fermilab /Serpukhov, IHEP /Novosibirsk, IYF /Serpukhov, IHEP /Fermilab

    2008-08-01

    The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  4. Lensing convergence in galaxy redshift surveys

    CERN Document Server

    Cardona, Wilmar; Kunz, Martin; Montanari, Francesco

    2016-01-01

    In this letter we demonstrate the importance of including the lensing contribution in galaxy clustering analyses with large galaxy redshift surveys. It is well known that radial cross-correlations between different redshift bins of galaxy surveys are dominated by lensing. But we show here that also neglecting lensing in the auto-correlations within one bin severely biases cosmological parameter estimation with redshift surveys. It leads to significant shifts for several cosmological parameters, most notably the scalar amplitude, the scalar spectral index and in particular the neutrino mass scale. Especially the latter parameter is one of the main targets of future galaxy surveys.

  5. Nanofocusing refractive X-ray lenses

    Energy Technology Data Exchange (ETDEWEB)

    Boye, Pit

    2010-02-05

    This thesis is concerned with the optimization and development of the production of nanofocusing refractive X-ray lenses. These optics made of either silicon or diamond are well-suited for high resolution X-ray microscopy. The goal of this work is the design of a reproducible manufacturing process which allows the production of silicon lenses with high precision, high quality and high piece number. Furthermore a process for the production of diamond lenses is to be developed and established. In this work, the theoretical basics of X-rays and their interaction with matter are described. Especially, aspects of synchrotron radiation are emphasized. Important in X-ray microscopy are the different optics. The details, advantages and disadvantages, in particular those of refractive lenses are given. To achieve small X-ray beams well beyond the 100 nm range a small focal length is required. This is achieved in refractive lenses by moving to a compact lens design where several single lenses are stacked behind each other. The, so-called nanofocusing refractive lenses (NFLs) have a parabolic cylindrical shape with lateral structure sizes in the micrometer range. NFLs are produced by using micro-machining techniques. These micro-fabrication processes and technologies are introduced. The results of the optimization and the final fabrication process for silicon lenses are presented. Subsequently, two experiments that are exemplary for the use of NFLs, are introduced. The rst one employs a high-resolution scanning fluorescence mapping of a geological sample, and the second one is a coherent x-ray diffraction imaging (CXDI) experiment. CXDI is able to reconstruct the illuminated object from recorded coherent diffraction patterns. In a scanning mode, referred to as ptychography, this method is even able to reconstruct the illumination and the object simultaneously. Especially the reconstructed illumination and the possibility of computed propagation of the wave field along the

  6. Twin axial vortices generated by Fibonacci lenses.

    Science.gov (United States)

    Calatayud, Arnau; Ferrando, Vicente; Remón, Laura; Furlan, Walter D; Monsoriu, Juan A

    2013-04-22

    Optical vortex beams, generated by Diffractive Optical Elements (DOEs), are capable of creating optical traps and other multi-functional micromanipulators for very specific tasks in the microscopic scale. Using the Fibonacci sequence, we have discovered a new family of DOEs that inherently behave as bifocal vortex lenses, and where the ratio of the two focal distances approaches the golden mean. The disctintive optical properties of these Fibonacci vortex lenses are experimentally demonstrated. We believe that the versatility and potential scalability of these lenses may allow for new applications in micro and nanophotonics.

  7. Plastic Surgery Statistics

    Science.gov (United States)

    ... PSN PSEN GRAFT Contact Us News Plastic Surgery Statistics Plastic surgery procedural statistics from the American Society of Plastic Surgeons. Statistics by Year Print 2016 Plastic Surgery Statistics 2015 ...

  8. A retrospective analysis of vision correction and safety in keratoconus patients wearing Toris K soft contact lenses.

    Science.gov (United States)

    Sultan, Pinar; Dogan, Cezmi; Iskeleli, Guzin

    2016-12-01

    The purpose of this study was to investigate the efficacy and safety of the Toris K silicone hydrogel contact lens (SwissLens; Prilly, Switzerland) in keratoconus patients. A database with information on 50 keratoconus patients (64 eyes) fitted with Toris K soft contact lenses over a 2-year period was retrospectively reviewed. Demographic data, prefitting refraction, the reason for choosing the Toris K soft contact lens, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), best-corrected visual acuity with a rigid gas permeable lens (BCVA RGP), best-corrected visual acuity with the Toris K lens (BCVA Toris K), and complications were evaluated. The mean age ± standard deviation at the time of fitting was 27.92 ± 9.86 years. The mean spherical refractive power was -4.62 ± 6.53 dioptres, and the mean cylinder was -3.78 ± 2.43 dioptres. The most common reason for using Toris K soft contact lenses was an inability to fit the patient with a RGP contact lens. There was a statistically significant difference between UCVA and BCVA Toris K (p = 0.0001), as well as between BSCVA and BCVA Toris K (p = 0.0001). However, there was no statistically significant difference between BCVA Toris K and BCVA RGP (p = 0.20). Superficial punctate keratitis and giant papillary conjunctivitis were the most common complications. The Toris K contact lens is a viable alternative for the optical management of all grades of keratoconus. The Toris K soft contact lens is a promising alternative for the visual rehabilitation of keratoconus patients who cannot tolerate RGP lenses or achieve a good fit.

  9. A comparison between spectacles and RGP CL in correcting aphakic eyes%外伤或手术所致无晶状体眼透气性硬性角膜接触镜与框架眼镜矫正的比较

    Institute of Scientific and Technical Information of China (English)

    王雪; 马薇; 杨必; 刘陇黔

    2012-01-01

    Objective To evaluate the differences of the degree and corrected visual acuity between spectacles and contact lens in correcting aphakic eyes.Method 51 subjects were fitted with both RGP CL lenses and spectacles.They were first examined with corneal topography and refractometry,then were fitted with RCP CL trial lenses and lastly fitted with RGP CL lenses.Take 12 mm as mirror eye distance to calculate patients' needed diopters according to formula,then compared with the diopters of RGP CL lens.Results The differences of the degree in the two groups are not statistically significant.RGP CL lens provide a significant improvement in visual acuity.Conclusion RGP CL is safe and effective in correcting aphakics.%目的 探讨用框架眼镜和透气性硬性角膜接触镜( RGP CL)分别对无晶状体眼进行矫正后,两者在矫正视力和处方度数有无差异.方法 51例(53眼)无晶状体眼分别接受框架眼镜和RGP CL矫正,记录其矫正视力和处方度数,将框架眼镜处方度数使用12 mm镜眼距进行换算后,再对两组数据进行统计学分析.结果 发现RGP CL矫正视力明显优于框架眼镜矫正视力,差异有统计学意义;框架眼镜和RGP CL矫正无晶状体眼处方度数,差异无统计学意义.结论 用框架眼镜矫正效果可大致预估RGP CL矫正效果,但RGP CL矫正在视力舒适度及双眼视的获得较框架眼镜有不可取代的优势,并且对由于角膜不规则散光等造成的屈光矫正视力不佳,能取得更好的效果.在对无晶状体眼进行光学矫正时,应首选RGP CL.

  10. Plastic bronchitis

    Directory of Open Access Journals (Sweden)

    Anil Kumar Singhi

    2015-01-01

    Full Text Available Plastic bronchitis, a rare but serious clinical condition, commonly seen after Fontan surgeries in children, may be a manifestation of suboptimal adaptation to the cavopulmonary circulation with unfavorable hemodynamics. They are ominous with poor prognosis. Sometimes, infection or airway reactivity may provoke cast bronchitis as a two-step insult on a vulnerable vascular bed. In such instances, aggressive management leads to longer survival. This report of cast bronchitis discusses its current understanding.

  11. Dark Synergy Gravitational Lensing and the CMB

    CERN Document Server

    Hu, W

    2002-01-01

    Power spectra and cross-correlation measurements from the weak gravitational lensing of the cosmic microwave background (CMB) and the cosmic shearing of faint galaxies images will help shed light on quantities hidden from the CMB temperature anisotropies: the dark energy, the end of the dark ages, and the inflationary gravitational wave amplitude. Even with modest surveys, both types of lensing power spectra break CMB degeneracies and they can ultimately improve constraints on the dark energy equation of state w by over an order of magnitude. In its cross correlation with the integrated Sachs-Wolfe effect, CMB lensing offers a unique opportunity for a more direct detection of the dark energy and enables study of its clustering properties. By obtaining source redshifts and cross-correlations with CMB lensing, cosmic shear surveys provide tomographic handles on the evolution of clustering correspondingly better precision on the dark energy equation of state and density. Both can indirectly provide detections of...

  12. Weak Lensing Simulations for the SKA

    CERN Document Server

    Patel, Prina; Makhathini, Sphesihle; Abdalla, Filipe; Bacon, David; Brown, Michael L; Heywood, Ian; Jarvis, Matt; Smirnov, Oleg

    2015-01-01

    Weak gravitational lensing measurements are traditionally made at optical wavelengths where many highly resolved galaxy images are readily available. However, the Square Kilometre Array (SKA) holds great promise for this type of measurement at radio wavelengths owing to its greatly increased sensitivity and resolution over typical radio surveys. The key to successful weak lensing experiments is in measuring the shapes of detected sources to high accuracy. In this document we describe a simulation pipeline designed to simulate radio images of the quality required for weak lensing, and will be typical of SKA observations. We provide as input, images with realistic galaxy shapes which are then simulated to produce images as they would have been observed with a given radio interferometer. We exploit this pipeline to investigate various stages of a weak lensing experiment in order to better understand the effects that may impact shape measurement. We first show how the proposed SKA1-Mid array configurations perfor...

  13. Tear exchange and contact lenses: a review.

    Science.gov (United States)

    Muntz, Alex; Subbaraman, Lakshman N; Sorbara, Luigina; Jones, Lyndon

    2015-01-01

    Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses.

  14. The Sloan Nearby Cluster Weak Lensing Survey

    CERN Document Server

    Kubo, Jeffrey M; Hardin, Frances Mei; Kubik, Donna; Lawhorn, Kelsey; Lin, Huan; Nicklaus, Liana; Nelson, Dylan; Reis, Ribamar R R; Seo, Hee-Jong; Soares-Santos, Marcelle; Stebbins, Albert; Yunker, Tony

    2009-01-01

    We describe and present initial results of a weak lensing survey of nearby ($\\rm{z}\\lesssim0.1$) galaxy clusters in the Sloan Digital Sky Survey (SDSS). In this first study, galaxy clusters are selected from the SDSS spectroscopic galaxy cluster catalogs of \\citet{miller05} and \\citet{berlind06}. We report a total of seven individual low redshift cluster weak lensing measurements which include: A2048, A1767, A2244, A1066, A2199, and two clusters specifically identified with the C4 algorithm. Our program of weak lensing of nearby galaxy clusters in the SDSS will eventually reach $\\sim 200$ clusters, making it the largest weak lensing survey of individual galaxy clusters to date.

  15. Near-infrared spectroscopy for monitoring water permeability of optical coatings on plastics.

    Science.gov (United States)

    Schulz, U; Kaiser, N

    1997-02-01

    Near-infrared spectroscopy has been applied to determine the water content of plastic lenses. An analytical method is presented for monitoring the water permeability of thin layers on plastic optics by utilizing the reversible moisture absorption of organic polymers. As an example, scratch-resistant and antireflective layers on poly[diethylenglycol-bis(allylcarbonate)] lenses are investigated. The measurements demonstrate the relatively high water barrier of coatings deposited by plasma-ion-assisted deposition compared with classical physical vapor deposition coatings and polysiloxane dip coatings.

  16. Electron Lenses for particle collimation in LHC

    CERN Document Server

    Shiltsev, V

    2008-01-01

    Electron Lenses built and installed in Tevatron have proven themselves as safe and very reliable instruments which can be effectively used in hadron collider operation for a number of applications, including compensation of beam-beam effects , DC beam removal from abort gaps , as a diagnostic tool. In this presentation we – following original proposal – consider in more detail a possibility of using electron lenses with hollow electron beam for ion and proton collimation in LHC.

  17. Simulating HST observations of strong lensing clusters

    Science.gov (United States)

    Meneghetti, Massimo

    2014-10-01

    The Frontier Fields {FF} are using galaxy cluster gravitational lensing to boost the powers of Hubble and Spitzer to reveal the faintest galaxies yet observed. Accurate gravitational lensing models with uncertainty estimates are required to study some of the physical parameters of the lensed galaxies. Simulated HST observations of lensing clusters with known mass distributions are ideal to determine the accuracies of these modeling methods. Our team has begun performing these tests, demonstrating that integrated quantities such as lensed number counts are accurately recovered, enabling luminosity functions to be constrained. We have also begun to quantify magnification uncertainties for individual galaxies, but additional tests are needed. Here we propose to create a set of simulated osbervations of clusters selected to be analogs of the CLASH and FF clusters. They will include lensing effects and they will be delivered to the Mikulski Archive for Space Telescopes as a legacy product for others to analyze. They will be usable to extend our tests for robustly determine the accuracies in model magnification and mass measurements. Mass uncertainties will be a key ingredient in efforts to use galaxy clusters to constrain cosmology and theories of structure formation. Results from this program will also be useful to improve lens modeling methods toward more optimal use of the large numbers of lensing constraints available in deep FF imaging. This program will help astronomers realize the full potential of the large investments of Hubble, Spitzer, Chandra, and ground-based observing time in the FF, CLASH, and other past and future cluster lensing observations.

  18. Nation-building, industrialisation, and spectacle: Political functions of Gujarat’s Narmada pipeline project

    Directory of Open Access Journals (Sweden)

    Mona Luxion

    2017-06-01

    Full Text Available Since 2000 the Indian state of Gujarat has been working to construct a state-wide water grid to connect 75% of its approximately 60 million urban and rural residents to drinking water sourced from the controversial Sardar Sarovar Dam on the Narmada River. This project represents a massive undertaking – it is billed as the largest drinking water project in the world – and is part of a broader predilection toward large, concrete-heavy supply-side solutions to water insecurity across present-day India. This paper tracks the claims and narratives used to promote the project, the political context in which it has emerged, the purposes it serves and, following Ferguson (1990, the functioning of the discursive-bureaucratic 'machine' of which it is a product. The dam’s reinvention as the solution to Gujarat’s drinking water shortfall – increasingly for cities and Special Industrial Regions – reflects a concern with attracting and retaining foreign investment through the creation of socalled 'world-class' infrastructure. At the same time, this reinvention has contributed to a project of nationbuilding, while remaining cloaked in a discourse of technological neutrality. The heavy infrastructure renders visible Gujarat’s commitment to 'development' even when that promise has yet to be realised for many, while the promise of Narmada water gives Gujarat’s leaders political capital with favoured investors and political supporters. In conclusion, I suggest that the success of infrastructure mega-projects as a political tool is not intrinsically tied to their ability to achieve their technical and social objectives. Instead, the 'spectacle' of ambitious infrastructural development projects may well yield political gains that outweigh, for a time, the realworld costs of their inequity and unsustainability.

  19. Pesticides in blood from spectacled caiman (Caiman crocodilus) downstream of banana plantations in Costa Rica.

    Science.gov (United States)

    Grant, Paul B C; Woudneh, Million B; Ross, Peter S

    2013-11-01

    Spectacled caiman (Caiman crocodilus) are fish-eating crocodilians that inhabit freshwater habitat in tropical regions of the Americas. To assess the exposure of caiman to pesticides from banana plantations, the authors collected whole blood samples (30 mL) from 14 adult caiman that were captured in the North Atlantic region of Costa Rica. Blood samples were analyzed for 70 legacy- and current-use pesticides and breakdown products using newly developed ultra-trace, high-resolution mass spectrometry (HRMS). Caiman accumulated pesticides ranked by concentration as dieldrin > permethrin > mirex > 4,4'-DDE > alpha-endosulfan > heptachlor epoxide > oxychlordane > heptachlor > cypermethrin. Caiman within the high-intensity banana crop watershed of Rio Suerte had higher pesticide burdens relative to other more remote locations (F = 12.79; p = 0.00). Pesticide concentration decreased with distance from upstream banana plantations in this river system (F = 20.76; p = 0.00). Caiman body condition was negatively correlated with total pesticide concentrations (F = 6.23; p = 0.02) and with proximity to banana plantations (F = 5.05; p = 0.04). This suggests that either pesticides elicited toxic effects in caiman, resulting in diminished overall health, or that the quantity or quality of their prey was reduced by pesticides downstream of plantation waterways. The authors' results indicate that pesticide use in banana plantations is impacting a high trophic level species inhabiting one of the most important wilderness areas in Costa Rica (Tortuguero National Park).

  20. Constraining Source Redshift Distributions with Gravitational Lensing

    CERN Document Server

    Wittman, D

    2012-01-01

    We introduce a new method for constraining the redshift distribution of a set of galaxies, using weak gravitational lensing shear. Instead of using observed shears and redshifts to constrain cosmological parameters, we ask how well the shears around clusters can constrain the redshifts, assuming fixed cosmological parameters. This provides a check on photometric redshifts, independent of source spectral energy distribution properties and therefore free of confounding factors such as misidentification of spectral breaks. We find that ~40 massive ($\\sigma_v=1200$ km/s) cluster lenses are sufficient to determine the fraction of sources in each of six coarse redshift bins to ~11%, given weak (20%) priors on the masses of the highest-redshift lenses, tight (5%) priors on the masses of the lowest-redshift lenses, and only modest (20-50%) priors on calibration and evolution effects. Additional massive lenses drive down uncertainties as $N_{lens}^0.5$, but the improvement slows as one is forced to use lenses further ...

  1. Cosmological test using strong gravitational lensing systems

    CERN Document Server

    Yuan, C C

    2015-01-01

    As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay $\\Delta\\tau$ of images, the velocity dispersion $\\sigma$ of the lensing galaxies and the combination of these two effects, $\\Delta\\tau/\\sigma^2$. In this paper, in order to carry out one-on-one comparisons between $\\Lambda$CDM universe and $R_h=ct$ universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the SLACS and LSD survey. Concerning the time-delay effect, 12 two-image lensing systems with $\\Delta\\tau$ are also used. In addition, Monte Carlo (MC) simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the $99.7\\%$ confidence level. Compar...

  2. Equatorial potassium currents in lenses.

    Science.gov (United States)

    Wind, B E; Walsh, S; Patterson, J W

    1988-02-01

    Earlier work with the vibrating probe demonstrated the existence of outward potassium currents at the equator and inward sodium currents at the optical poles of the lens. By adding microelectrodes to the system, it is possible to relate steady currents (J) to the potential difference (PD) measured with a microelectrode. By injecting an outward current (I), it is possible to determine resistances and also the PD at which the steady outward potassium current becomes zero (PDJ = 0). At this PD the concentration gradient for potassium efflux and the electrical gradient for potassium influx are balanced so that there is no net flow of potassium across the membranes associated with the production of J. The PDJ = 0 for 18 rat lenses was 86 mV and that for 12 frogs lenses was -95 mV. This agrees with the potassium equilibrium potential and provides strong evidence to support the view that the outward equatorial current, J, is a potassium current. With the injection of outward current, I, the PD becomes more negative, the outward equatorial current, J, decreases, and the inward current at the optical poles increases. This suggests that there are separate electrical loops for K+ and Na+ that are partially linked by the Na, K-pump. Using Ohm's law, it is possible to calculate the input resistance (R = delta PD/I), the resistance related to the production of J (RJ = delta PD/delta J), and the effect of the combined resistances (delta J/I). The driving force for J can be estimated (PDJ = 0-PD). The relationships among currents, voltages and resistance can be used to determine the characteristics of the membranes that are associated with the outward potassium current observed at the equator. The effects of graded deformation of the lens were determined. The effects were reversible. The sites of inward and outward currents were not altered. Following deformation, the equatorial current, J, increased, and the PD became less negative. The PDJ = 0 remains the same so the ratio of K

  3. Laser ablation cleaning of an underwater archaeological bronze spectacle plate from the H.M.S. DeBraak shipwreck

    Science.gov (United States)

    Dajnowski, Bartosz A.

    2013-05-01

    Laser ablation was successfully used to sequentially remove layers of concretion and corrosion from the surface of a copper alloy spectacle plate from the shipwreck of His Majesty's Sloop of War DeBraak. The H.M.S. DeBraak was a single-masted cutter that was originally a Dutch ship until it was taken by the British, refitted, and repurposed as a Royal Navy ship in 1796. The ship sank along the Delaware coast in 1798 and artifacts were recovered from the wreck site in 1984. This spectacle plate is an important part of the ships rudder and it is part of the collection of the Delaware Division of Historical and Cultural Affairs. The object was brought the Winterthur/University of Delaware Program in Art Conservation for treatment. The object was examined with cross section microscopy, Raman spectroscopy, X-ray fluorescence spectroscopy (XRF), and Energy Dispersive Spectroscopy (EDS) as well as Back Scattered Electron (BSE) analysis with a Scanning Electron Microscopy (SEM). Interestingly, layers of both copper and iron corrosion products were identified within the concretion. A 1064nm Long Q-Switch (LQS) laser with 100ns pulses was tested along with a Short Free Running (SFR) with 60 - 130 microseconds pulses, at various fluences and frequencies, to determine optimal cleaning parameters for removing the concretion. Laser cleaning also revealed fragments of wood from the original rudder, which were previously trapped within the concretion. After laser cleaning, the spectacle plate was treated with 3% Benzotriazole in ethanol and then given a protective microcrystalline wax coating.

  4. Comparison of refractive errors and factors associated with spectacle use in a rural and urban South Indian population

    Directory of Open Access Journals (Sweden)

    Prema Raju

    2008-01-01

    Full Text Available Purpose: To compare the prevalence of refractive errors and factors associated with spectacle use in a rural and urban south Indian population. Materials and Methods: Four thousand eight hundred subjects (age> 39 years each from rural and urban Tamil Nadu were enumerated for a population-based study. All participants underwent a complete ophthalmic evaluation including best-corrected visual acuity (BCVA, objective and subjective refraction. Out of 3924 rural responders 63.91% and out of 3850 urban responders 81.64% were phakic in the right eye with BCVA of 20/40 or better and were included in the study. Association of spectacle use and refractive errors with different parameters were analysed using logistic regression. Statistical Analysis: Chi square, t test, Chi square for trend and Pearson′s correlation coefficient were used for analysis. Results: Spectacle use was significantly higher and positively associated with literacy and employment in the urban population. The age and gender-adjusted prevalence of emmetropia, myopia of spherical equivalent (SE ≤-0.50 diopter sphere (DS, high myopia (SE ≤-5.00DS, hyperopia (SE> 0.50DS and astigmatism ≤ 0.50 diopter cylinder (DC were 46.8%, 31.0%, 4.3%, 17.9% and 60.4% respectively in the rural population and 29.0%, 17.6%, 1.5%, 51.9%, 59.1% respectively in the urban population. The prevalence of emmetropia decreased with age ( p < 0.001; prevalence of myopia and high myopia increased with age ( p = 0.001 and were associated with nuclear sclerosis ( p = 0.001 in both populations. Hyperopia was commoner among women than men ( p = 0.001; was positively associated with diabetes mellitus ( p = 0.008 in the rural population and negatively with nuclear sclerosis ( p = 0.001 in both populations. Conclusion: Spectacle use was found to be significantly lower in the rural population. The pattern of refractive errors was significantly different between both populations.

  5. Optimal Weak Lensing Skewness Measurements

    CERN Document Server

    Zhang, T J; Zhang, P; Dubinski, J; Zhang, Tong-Jie; Pen, Ue-Li; Zhang, Pengjie; Dubinski, John

    2003-01-01

    Weak lensing measurements are entering a precision era to statistically map the distribution of matter in the universe. The most common measurement has been of the variance of the projected surface density of matter, which corresponds to the induced correlation in alignments of background galaxies. This measurement of the fluctuations is insensitive to the total mass content, like using waves on the ocean to measure its depths. But when the depth is shallow as happens near a beach, waves become skewed. Similarly, a measurement of skewness in the projected matter distribution directly measures the total matter content of the universe. While skewness has already been convincingly detected, its constraint on cosmology is still weak. We address optimal analyses for the CFHT Legacy Survey in the presence of noise. We show that a compensated Gaussian filter with a width of 2.5 arc minutes optimizes the cosmological constraint, yielding $\\Delta \\Omega_m/\\Omega_m\\sim 10%$. This is significantly better than other filt...

  6. Surface Modification of Intraocular Lenses

    Directory of Open Access Journals (Sweden)

    Qi Huang

    2016-01-01

    Full Text Available Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs. Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol, polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO 2 , heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs.

  7. Thin lenses of asymmetric power

    Directory of Open Access Journals (Sweden)

    W. F. Harris

    2009-12-01

    Full Text Available It is generally supposed that thin systems, including refracting surfaces and thin lenses, have powers that are necessarily symmetric.  In other words they have powers which can be represented assymmetric dioptric power matrices and in the familar spherocylindrical form used in optometry and ophthalmology.  This paper shows that this is not correct and that it is indeed possible for a thin system to have a power that is not symmetric and which cannot be expressed in spherocylindrical form.  Thin systems of asymmetric power are illustratedby means of a thin lens that is modelled with small prisms and is chosen to have a dioptric power ma-trix that is antisymmetric.  Similar models can be devised for a thin system whose dioptric power matrix is any  2 2 ×  matrix.  Thus any power, symmetric, asymmetric or antisymmetric, is possible for a thin system.  In this sense our understanding of the power of thin systems is now complete.

  8. Degeneracy between Lensing and Occultation in the Analysis of Self-lensing Phenomena

    CERN Document Server

    Han, Cheongho

    2016-01-01

    More than 40 years after the first discussion, it was recently reported the detection of a self-lensing phenomenon within a binary system where the brightness of a background star is magnified by its foreground companion. It is expected that the number of self-lensing binary detections will be increased in a wealth of data from current and future survey experiments. In this paper, we introduce a degeneracy in the interpretation of self-lensing light curves. The degeneracy is intrinsic to self-lensing binaries for which both magnification by lensing and de-magnification by occultation occur simultaneously and is caused by the difficulty in separating the contribution of the lensing-induced magnification from the observed light curve. We demonstrate the severity of the degeneracy by presenting example self-lensing light curves suffering from the degeneracy. We also present the relation between the lensing parameters of the degenerate solutions. The degeneracy would pose as an important obstacle in accurately de...

  9. DESIGN OF THE MULTIORDER INTRAOCULAR LENSES

    Directory of Open Access Journals (Sweden)

    V. G. Kolobrodov

    2015-01-01

    Full Text Available Intraocular lenses (IOLs are used to replace the natural crystalline lens of the eye. Just few basic designs of IOLs are used clinically. Multiorder diffractive lenses (MODL which operate simultaneously in several diffractive orders were proposed to decrease the chromatic aberration. Properties analysis of MODL showed a possibility to use them to develop new designs of IOLs. The purpose of this paper was to develop a new method of designing of multiorder intraocular lenses with decreased chromatic aberration. The theoretical research of the lens properties was carried out. The diffraction efficiency dependence with the change of wavelength was studied. A computer simulation of MODL in a schematic model of the human eye was carried out. It is found the capability of the multiorder diffractive lenses to focus polychromatic light into a segment on the optical axis with high diffraction efficiency. At each point of the segment is present each component of the spectral range, which will build a color image in combination. The paper describes the new design method of intraocular lenses with reduced chromaticism and with endless adaptation. An optical system of an eye with an intraocular lens that provides sharp vision of objects located at a distance of 700 mm to infinity is modeled.

  10. CMB-lensing beyond the Born approximation

    Science.gov (United States)

    Marozzi, Giovanni; Fanizza, Giuseppe; Di Dio, Enea; Durrer, Ruth

    2016-09-01

    We investigate the weak lensing corrections to the cosmic microwave background temperature anisotropies considering effects beyond the Born approximation. To this aim, we use the small deflection angle approximation, to connect the lensed and unlensed power spectra, via expressions for the deflection angles up to third order in the gravitational potential. While the small deflection angle approximation has the drawback to be reliable only for multipoles l lesssim 2500, it allows us to consistently take into account the non-Gaussian nature of cosmological perturbation theory beyond the linear level. The contribution to the lensed temperature power spectrum coming from the non-Gaussian nature of the deflection angle at higher order is a new effect which has not been taken into account in the literature so far. It turns out to be the leading contribution among the post-Born lensing corrections. On the other hand, the effect is smaller than corrections coming from non-linearities in the matter power spectrum, and its imprint on CMB lensing is too small to be seen in present experiments.

  11. Cidadania virtual: o espetáculo do governo eletrônico Virtual citizenship: the spectacle of eletronic government

    Directory of Open Access Journals (Sweden)

    Gilda Maria Azevedo Alves dos Anjos

    2011-04-01

    Full Text Available O artigo apresenta uma análise crítica das justifi cativas para implantação e expansão dos serviços públicos oferecidos pela Internet, o chamado “Governo Eletrônico” (e-Gov. Discute temas atuais como cidadania virtual e inclusão digital, confrontando-os com as diretrizes do e-Gov e indicadores publicados pelo Comitê Gestor da Internet no Brasil (CGI. As discussões desenvolvidas têm como base as teses de Guy Debord, que estimulam a visão crítica do processo de espetacularização da cidadania. Palavras-chave: Cidadania. Serviço público. Governo eletrônico. Inclusão digital. Espetáculo. The study presents a critical analysis on the justification for the implementing and expanding public services offered on the Internet, the so-called “Electronic Government” (e-Gov. It shows current subjects such as the virtual citizenship and the digital inclusion program, and puts them in confront to the e-Gov directives and the indicators issued by the Brazilian Internet Steering Committee Group (CGI. The discussions are based on the Guy Debord’s theses, which enhance the critical view of Society of the Spectacle process of the citizenship. Keywords: Citizenship. Public service. Electronic government. Digital inclusion. Spectacle.

  12. Overcoming maladaptive plasticity through plastic compensation

    Directory of Open Access Journals (Sweden)

    Matthew R.J. MORRIS, Sean M. ROGERS

    2013-08-01

    Full Text Available Most species evolve within fluctuating environments, and have developed adaptations to meet the challenges posed by environmental heterogeneity. One such adaptation is phenotypic plasticity, or the ability of a single genotype to produce multiple environmentally-induced phenotypes. Yet, not all plasticity is adaptive. Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution, much less is known about maladaptive plasticity. However, maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments. This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity, two of which involve genetic changes (standing genetic variation, genetic compensation and two of which do not (standing epigenetic variation, plastic compensation. Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity. In particular, plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence. We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change [Current Zoology 59 (4: 526–536, 2013].

  13. Overcoming maladaptive plasticity through plastic compensation

    Institute of Scientific and Technical Information of China (English)

    Matthew R.J.MORRIS; Sean M.ROGERS

    2013-01-01

    Most species evolve within fluctuating environments,and have developed adaptations to meet the challenges posed by environmental heterogeneity.One such adaptation is phenotypic plasticity,or the ability of a single genotype to produce multiple environmentally-induced phenotypes.Yet,not all plasticity is adaptive.Despite the renewed interest in adaptive phenotypic plasticity and its consequences for evolution,much less is known about maladaptive plasticity.However,maladaptive plasticity is likely an important driver of phenotypic similarity among populations living in different environments.This paper traces four strategies for overcoming maladaptive plasticity that result in phenotypic similarity,two of which involve genetic changes (standing genetic variation,genetic compensation) and two of which do not (standing epigenetic variation,plastic compensation).Plastic compensation is defined as adaptive plasticity overcoming maladaptive plasticity.In particular,plastic compensation may increase the likelihood of genetic compensation by facilitating population persistence.We provide key terms to disentangle these aspects of phenotypic plasticity and introduce examples to reinforce the potential importance of plastic compensation for understanding evolutionary change.

  14. Trapping light by mimicking gravitational lensing

    CERN Document Server

    Sheng, C; Wang, Y; Zhu, S N; Genov, D A

    2013-01-01

    One of the most fascinating predictions of the theory of general relativity is the effect of gravitational lensing, the bending of light in close proximity to massive stellar objects. Recently, artificial optical materials have been proposed to study the various aspects of curved spacetimes, including light trapping and Hawking's radiation. However, the development of experimental toy models that simulate gravitational lensing in curved spacetimes remains a challenge, especially for visible light. Here, by utilizing a microstructured optical waveguide around a microsphere, we propose to mimic curved spacetimes caused by gravity, with high precision. We experimentally demonstrate both far-field gravitational lensing effects and the critical phenomenon in close proximity to the photon sphere of astrophysical objects under hydrostatic equilibrium. The proposed microstructured waveguide can be used as an omnidirectional absorber, with potential light harvesting and microcavity applications.

  15. The conceptual origins of gravitational lensing

    CERN Document Server

    Valls-Gabaud, David

    2012-01-01

    We critically examine the evidence available of the early ideas on the bending of light due to a gravitational attraction, which led to the concept of gravitational lenses, and attempt to present an undistorted historical perspective. Contrary to a widespread but baseless claim, Newton was not the precursor to the idea, and the first Query in his {\\sl Opticks} is totally unrelated to this phenomenon. We briefly review the roles of Voltaire, Marat, Cavendish, Soldner and Einstein in their attempts to quantify the gravitational deflection of light. The first, but unpublished, calculations of the lensing effect produced by this deflection are found in Einstein's 1912 notebooks, where he derived the lensing equation and the formation of images in a gravitational lens. The brief 1924 paper by Chwolson which presents, without calculations, the formation of double images and rings by a gravitational lens passed mostly unnoticed. The unjustly forgotten and true pioneer of the subject is F. Link, who not only publishe...

  16. Electron lenses for super-colliders

    CERN Document Server

    Shiltsev, Vladimir D

    2016-01-01

    This book provides a comprehensive overview of the operating principles and technology of electron lenses in supercolliders.  Electron lenses are a novel instrument for high energy particle accelerators, particularly for the energy-frontier superconducting hadron colliders, including the Tevatron, RHIC, LHC and future very large hadron colliders.  After reviewing the issues surrounding beam dynamics in supercolliders, the book offers an introduction to the electron lens method and its application.  Further chapters describe the technology behind the electron lenses which have recently been proposed, built and employed for compensation of beam-beam effects and for collimation of high-energy high-intensity beams, for compensation of space-charge effects and several other applications in accelerators. The book will be an invaluable resource for those involved in the design, construction and operation of the next generation of hadron colliders.

  17. Developments in projection lenses for HDTV

    Science.gov (United States)

    Rudolph, John D.

    1991-08-01

    Recent focus on the development of HDTV systems worldwide has raised a critical concern--the economic viability of HDTV for the home marketplace. While projection systems performing at or above HDTV-quality levels exist today, they are designed for the institutional market and are priced far above the threshold for the individual consumer. Manufacturers will be under considerable pressure to significantly reduce the cost of HDTV projectors, as will the suppliers of key components such as lenses. Fortunately, recent developments have been made in the design, development and manufacturing technologies used to produce hybrid lenses for high-performance projection systems. This is particularly true for CRT-based front- and rear-projection systems for data and graphics applications. Extending these advances to HDTV would suggest that by the time HDTV is ready for high volume mass production, cost-effective projection lenses will be enhancing, not retarding, the market acceptance of HDTV.

  18. Cluster mass reconstruction from weak gravitational lensing

    CERN Document Server

    Wilson, G; Frenk, C S; Wilson, Gillian; Cole, Shaun; Frenk, Carlos S

    1996-01-01

    Kaiser & Squires have proposed a technique for mapping the dark matter in galaxy clusters using the coherent weak distortion of background galaxy images caused by gravitational lensing. We investigate the effectiveness of this technique under controlled conditions by creating simulated CCD frames containing galaxies lensed by a model cluster, measuring the resulting galaxy shapes, and comparing the reconstructed mass distribution with the original. Typically, the reconstructed surface density is diminished in magnitude when compared to the original. The main cause of this reduced signal is the blurring of galaxy images by atmospheric seeing, but the overall factor by which the reconstructed surface density is reduced depends also on the signal-to-noise ratio in the CCD frame and on both the sizes of galaxy images and the magnitude limit of the sample that is analysed. We propose a method for estimating a multiplicative compensation factor. We test our technique using a lensing cluster drawn from a cosmolo...

  19. Orbital Motion During Gravitational Lensing Events

    CERN Document Server

    Di Stefano, Rosanne

    2014-01-01

    Gravitational lensing events provide unique opportunities to discover and study planetary systems and binaries. Here we build on previous work to explore the role that orbital motion can play in both identifying and learning more about multiple-mass systems that serve as gravitational lenses. We find that a significant fraction of planet-lens and binary-lens light curves are influenced by orbital motion. Furthermore, the effects of orbital motion extend the range of binaries for which lens multiplicity can be discovered and studied. Orbital motion will play an increasingly important role as observations with sensitive photometry, such as those made by the space missions Kepler, Transiting Exoplanet Survey Satellite, (TESS), and WFIRST discover gravitational lensing events. Similarly, the excellent astrometric measurements made possible by GAIA will allow it to study the effects of orbital motion. Frequent observations, such as those made possible with the Korean Microlensing Telescope Network, KMTNet, will al...

  20. WMAP anomaly : Weak lensing in disguise

    CERN Document Server

    Rotti, Aditya; Souradeep, Tarun

    2011-01-01

    Statistical isotropy (SI) has been one of the simplifying assumptions in cosmological model building. Experiments like WMAP and PLANCK are attempting to test this assumption by searching for specific signals in the Cosmic Microwave Background (CMB) two point correlation function. Modifications to this correlation function due to gravitational lensing by the large scale structure (LSS) surrounding us have been ignored in this context. Gravitational lensing will induce signals which mimic isotropy violation even in an isotropic universe. The signal detected in the Bipolar Spherical Harmonic (BipoSH) coefficients $A^{20}_{ll}$ by the WMAP team may be explained by accounting for the lensing modifications to these coefficients. Further the difference in the amplitude of the signal detected in the V-band and W-band maps can be explained by accounting for the differences in the designed angular sensitivity of the instrumental beams. The arguments presented in this article have crucial implications for SI violation s...

  1. Weak lensing in the Dark Energy Survey

    Science.gov (United States)

    Troxel, Michael

    2016-03-01

    I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.

  2. Interactions of benzalkonium chloride with soft and hard contact lenses

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, J.M.; Cheeks, L.; Green, K. (Medical College of Georgia, Augusta (USA))

    1990-02-01

    We measured the uptake and washout of benzalkonium chloride, using radioactive tracer, by representative hard and soft contact lenses. Uptake by soft contact lenses after 7 days of continuous exposure is high (30 to 56 micrograms/mg of lens weight), with a low percentage of washout in 24 hours (between 0.2% and 1.5% of total uptake). High-water content lenses absorb greater quantities of benzalkonium than do low-water content lenses. Hard lenses take up a much smaller quantity of benzalkonium but release between 30% and 60% of total uptake during washout for 24 hours. Fluorosilicone-acrylate polymer lenses adsorb and release the most preservative, while polymethylmethacrylate lenses (Paragon Optical Inc, Mesa, Ariz) adsorb and release the least. The released benzalkonium from either soft or hard lenses is of a sufficient concentration to be at or above the upper limits of safety.

  3. PICS: Simulations of Strong Gravitational Lensing in Galaxy Clusters

    CERN Document Server

    Li, Nan; Rangel, Esteban M; Florian, Michael K; Bleem, Lindsey E; Heitmann, Katrin; Habib, Salman; Fasel, Patricia

    2015-01-01

    Gravitational lensing has become one of the most powerful tools available for investigating the 'dark side' of the universe. Cosmological strong gravitational lensing, in particular, probes the properties of the dense cores of dark matter halos over decades in mass and offers the opportunity to study the distant universe at flux levels and spatial resolutions otherwise unavailable. Studies of strongly-lensed variable sources offer yet further scientific opportunities. One of the challenges in realizing the potential of strong lensing is to understand the statistical context of both the individual systems that receive extensive follow-up study, as well as that of the larger samples of strong lenses that are now emerging from survey efforts. Motivated by these challenges, we have developed an image-simulation pipeline, PICS (Pipeline for Images of Cosmological Strong lensing) to generate realistic strong gravitational lensing signals from group and cluster scale lenses. PICS uses a low-noise and unbiased densit...

  4. High-speed optical signal processing using time lenses

    DEFF Research Database (Denmark)

    Galili, Michael; Hu, Hao; Guan, Pengyu;

    2015-01-01

    This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

  5. Scalar field haloes as gravitational lenses

    CERN Document Server

    Schunck, F E; Mielke, E W

    2006-01-01

    A non-topological soliton model with a repulsive scalar self-interaction of the Emden type provides a constant density core,similarly as the empirical Burkert profile of dark matter haloes. As a further test, we derive the gravitational lens properties of our model, in particular, the demarcation curves between `weak' and `strong' lensing. Accordingly, strong lensing with typically three images is almost three times more probable for our solitonic model than for the Burkert fit. Moreover, some prospective consequences of a possible flattening of dark matter haloes are indicated.

  6. Measuring the dark side (with weak lensing)

    CERN Document Server

    Amendola, Luca; Sapone, Domenico

    2007-01-01

    We introduce a convenient parametrization of dark energy models that is general enough to include several modified gravity models and generalized forms of dark energy. In particular we take into account the linear perturbation growth factor, the anisotropic stress and the modified Poisson equation. We discuss the sensitivity of large scale weak lensing surveys like the proposed DUNE satellite to these parameters. We find that a large-scale weak-lensing tomographic survey is able to easily distinguish the Dvali-Gabadadze-Porrati model from LCDM and to determine the perturbation growth index to an absolute error of 0.02-0.03.

  7. Achromatic Cooling Channel with Li Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Balbekov, V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2002-04-29

    A linear cooling channel with Li lenses, solenoids, and 201 MHz RF cavities is considered. A special lattice design is used to minimize chromatic aberrations by suppression of several betatron resonances. Transverse emittance of muon beam decreases from 2 mm to 0.5 mm at the channel of about 110 m length. Longitudinal heating is modest, therefore transmission of the channel is rather high: 96% without decay and 90% with decay. Minimal beam emittance achievable by similar channel estimated as about 0.25 mm at surface field of Li lenses 10 T.

  8. High Performance Atomically Thin Flat Lenses

    CERN Document Server

    Lin, Han; Qiu, Chengwei; Jia, Baohua; Bao, Qiaoliang

    2016-01-01

    We experimentally demonstrate ultrathin flat lenses with a thickness of 7 {\\AA}, which corresponds to the fundamental physical limit of the thickness of the material, is fabricated in a large area, monolayer, CVD-prepared tungsten chalcogenides single crystals using the low-cost flexible laser writing method. The lenses apply the ultra-high refractive index to introduce abrupt amplitude modulation of the incident light to achieve three-dimensional (3D) focusing diffraction-limited resolution (0.5{\\lambda}) and a focusing efficiency as high as 31%. An analytical physical model based diffraction theory is derived to simulate the focusing process, which shows excellent agreement with the experimental results.

  9. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like......, good strength and long durability. Recycling of plastic waste from production is well-established, while recycling of postconsumer plastic waste still is in its infancy. This chapter describes briefly how plastic is produced and how waste plastic is recycled in the industry. Quality requirements...

  10. The Health and Social Security Act 1984 and the price of spectacles among corporate practices in the United Kingdom (1980-2007): a review.

    Science.gov (United States)

    Calver, Richard

    2010-03-01

    The Health and Social Security Act 1984 deregulated certain aspects of optometry in the United Kingdom, including advertising and the supply of spectacles, in the hope that greater competition would reduce spectacle prices. The effects of this legislation are tested by plotting the mean prices of private spectacles purchased from corporate optometric practices, from 1980 to 2007. Historical evidence is used to gauge the effect on prices of other factors such as National Health Service (NHS) payments, sight test fees and pressure exerted by consumer organisations. The high prices in 1980 reduced markedly throughout the rest of the 1980s, remained low for most of the 1990s and rose between 1999 and 2003, before falling. Changes in price were associated with changes to the system of NHS payments and variations in private sight test fees, but prices have generally been lower since the deregulation of dispensing than they were before. Although the price of private spectacles remains heavily influenced by other factors, the deregulation of opticians' services has benefited the public by maintaining lower prices, as intended by proponents of the legislation.

  11. Analysis of luminosity distributions of strong lensing galaxies: subtraction of diffuse lensed signal

    Science.gov (United States)

    Biernaux, J.; Magain, P.; Hauret, C.

    2017-08-01

    Context. Strong gravitational lensing gives access to the total mass distribution of galaxies. It can unveil a great deal of information about the lenses' dark matter content when combined with the study of the lenses' light profile. However, gravitational lensing galaxies, by definition, appear surrounded by lensed signal, both point-like and diffuse, that is irrelevant to the lens flux. Therefore, the observer is most often restricted to studying the innermost portions of the galaxy, where classical fitting methods show some instabilities. Aims: We aim at subtracting that lensed signal and at characterising some lenses' light profile by computing their shape parameters (half-light radius, ellipticity, and position angle). Our objective is to evaluate the total integrated flux in an aperture the size of the Einstein ring in order to obtain a robust estimate of the quantity of ordinary (luminous) matter in each system. Methods: We are expanding the work we started in a previous paper that consisted in subtracting point-like lensed images and in independently measuring each shape parameter. We improve it by designing a subtraction of the diffuse lensed signal, based only on one simple hypothesis of symmetry. We apply it to the cases where it proves to be necessary. This extra step improves our study of the shape parameters and we refine it even more by upgrading our half-light radius measurement method. We also calculate the impact of our specific image processing on the error bars. Results: The diffuse lensed signal subtraction makes it possible to study a larger portion of relevant galactic flux, as the radius of the fitting region increases by on average 17%. We retrieve new half-light radii values that are on average 11% smaller than in our previous work, although the uncertainties overlap in most cases. This shows that not taking the diffuse lensed signal into account may lead to a significant overestimate of the half-light radius. We are also able to measure

  12. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...

  13. Software for Fermat's Principle and Lenses

    Science.gov (United States)

    Mihas, Pavlos

    2012-01-01

    Fermat's principle is considered as a unifying concept. It is usually presented erroneously as a "least time principle". In this paper we present some software that shows cases of maxima and minima and the application of Fermat's principle to the problem of focusing in lenses. (Contains 12 figures.)

  14. GRAVITATIONAL LENSES AND UNCONVENTIONAL GRAVITY THEORIES

    NARCIS (Netherlands)

    BEKENSTEIN, JD; SANDERS, RH

    1994-01-01

    We study gravitational lensing by clusters of galaxies in the context of the generic class of unconventional gravity theories which describe gravity in terms of a metric and one or more scalar fields (called here scalar-tensor theories). We conclude that, if the scalar fields have positive energy, t

  15. Studying dark matter haloes with weak lensing

    NARCIS (Netherlands)

    Velander, Malin Barbro Margareta

    2012-01-01

    Our Universe is comprised not only of normal matter but also of unknown components: dark matter and dark energy. This Thesis recounts studies of dark matter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes

  16. Studying dark matter haloes with weak lensing

    NARCIS (Netherlands)

    Velander, Malin Barbro Margareta

    2012-01-01

    Our Universe is comprised not only of normal matter but also of unknown components: dark matter and dark energy. This Thesis recounts studies of dark matter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes ana

  17. Modern scleral lenses part II: patient satisfaction.

    NARCIS (Netherlands)

    Visser, E.S.; Visser, R.; Lier, H.J.J. van; Otten, H.M.

    2007-01-01

    PURPOSE: To evaluate the subjective performance of modern scleral lenses in patients of the clinics of Visser Contact Lens Practice. METHODS: In this cross-sectional survey, all the necessary data were collected at the first follow-up visit during the 5-month study period. In accordance with the

  18. Doubling strong lensing as a cosmological probe

    Science.gov (United States)

    Linder, Eric V.

    2016-10-01

    Strong gravitational lensing provides a geometric probe of cosmology in a unique manner through distance ratios involving the source and lens. This is well-known for the time delay distance derived from measured delays between lightcurves of the images of variable sources such as quasars. Recently, double source plane lens systems involving two constant sources lensed by the same foreground lens have been proposed as another probe, involving a different ratio of distances measured from the image positions and fairly insensitive to the lens modeling. Here we demonstrate that these two different sets of strong lensing distance ratios have strong complementarity in cosmological leverage. Unlike other probes, the double source distance ratio is actually more sensitive to the dark energy equation of state parameters w0 and wa than to the matter density Ωm, for low redshift lenses. Adding double source distance ratio measurements can improve the dark energy figure of merit by 40% for a sample of fewer than 100 low redshift systems, or even better for the optimal redshift distribution we derive.

  19. Strong gravitational lensing versus dynamic galactic mass

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Antonio C.C.; Sodre Junior, Laerte [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Astronomia

    2006-07-01

    The mass associated to a galaxy is a fundamental property necessary for its description and for the understating of its structure, formation and evolution. In the cosmological context, the mass and density profile of galaxies and galaxy clusters is relevant for the understanding of dark matter properties and the formation dynamics of structures in the Universe. We find the masses of 15 galaxies from the SLACS Survey through two methods: using the stellar velocity dispersion (dynamic method) and using strong gravitational lensing. We discover a discrepancy between the masses obtained through these two methods and develop several models to explain it. We test the models suggested by calculating {chi}{sup 2} statistics and the Bayesian information criteria. Statistical fluctuation and a constant systematic error are strongly discarded as explanations for the mass discrepancy. Our results show evidence of projection effects on the line of sight that add a contamination mass in the strong lensing galactic mass determination. This effect was already observed in greater detail in weak and strong gravitational lensing measures of cluster of galaxies, but was little explored before in the case of strong lensing by galaxies. (author)

  20. Modern scleral lenses part II: patient satisfaction.

    NARCIS (Netherlands)

    Visser, E.S.; Visser, R.; Lier, H.J.J. van; Otten, H.M.

    2007-01-01

    PURPOSE: To evaluate the subjective performance of modern scleral lenses in patients of the clinics of Visser Contact Lens Practice. METHODS: In this cross-sectional survey, all the necessary data were collected at the first follow-up visit during the 5-month study period. In accordance with the pre

  1. Spurious Shear in Weak Lensing with LSST

    CERN Document Server

    Chang, C; Jernigan, J G; Peterson, J R; AlSayyad, Y; Ahmad, Z; Bankert, J; Bard, D; Connolly, A; Gibson, R R; Gilmore, K; Grace, E; Hannel, M; Hodge, M A; Jee, M J; Jones, L; Krughoff, S; Lorenz, S; Marshall, P J; Marshall, S; Meert, A; Nagarajan, S; Peng, E; Rasmussen, A P; Shmakova, M; Sylvestre, N; Todd, N; Young, M

    2012-01-01

    The Large Synoptic Survey Telescope (LSST) is one of the most powerful ground-based weak lensing survey telescopes in the upcoming decade. The complete 10-year survey will image $\\sim$ 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to $r\\sim27.5$, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of \\textit{additive} systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing ana...

  2. Strong lensing interferometry for compact binaries

    NARCIS (Netherlands)

    Pen, U.L.; Yang, I.S.

    2015-01-01

    We propose a possibility to improve the current precision measurements on compact binaries. When the orbital axis is almost perpendicular to our line of sight, a pulsar behind its companion can form two strong lensing images. These images cannot be resolved, but we can use multiwavelength interferom

  3. Improving lensing cluster mass estimate with flexion

    CERN Document Server

    Cardone, Vincenzo F; Er, Xinzhong; Maoli, Roberto; Scaramella, Roberto

    2016-01-01

    Gravitational lensing has long been considered as a valuable tool to determine the total mass of galaxy clusters. The shear profile as inferred from the statistics of ellipticity of background galaxies allows to probe the cluster intermediate and outer regions thus determining the virial mass estimate. However, the mass sheet degeneracy and the need for a large number of background galaxies motivate the search for alternative tracers which can break the degeneracy among model parameters and hence improve the accuracy of the mass estimate. Lensing flexion, i.e. the third derivative of the lensing potential, has been suggested as a good answer to the above quest since it probes the details of the mass profile. We investigate here whether this is indeed the case considering jointly using weak lensing, magnification and flexion. We use a Fisher matrix analysis to forecast the relative improvement in the mass accuracy for different assumptions on the shear and flexion signal - to - noise (S/N) ratio also varying t...

  4. Modern scleral lenses part II: patient satisfaction.

    NARCIS (Netherlands)

    Visser, E.S.; Visser, R.; Lier, H.J.J. van; Otten, H.M.

    2007-01-01

    PURPOSE: To evaluate the subjective performance of modern scleral lenses in patients of the clinics of Visser Contact Lens Practice. METHODS: In this cross-sectional survey, all the necessary data were collected at the first follow-up visit during the 5-month study period. In accordance with the pre

  5. GRAVITATIONAL LENSES AND UNCONVENTIONAL GRAVITY THEORIES

    NARCIS (Netherlands)

    BEKENSTEIN, JD; SANDERS, RH

    1994-01-01

    We study gravitational lensing by clusters of galaxies in the context of the generic class of unconventional gravity theories which describe gravity in terms of a metric and one or more scalar fields (called here scalar-tensor theories). We conclude that, if the scalar fields have positive energy,

  6. Electron Lenses for the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio [Fermilab; Valishev, Alexander [Fermilab; Bruce, Roderik [CERN; Redaelli, Stefano [CERN; Rossi, Adriana [CERN; Salvachua, Belen [CERN

    2014-07-01

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. This project is moving towards a technical design in 2014, with the goal to build the devices in 2015-2017, after resuming LHC operations and re-assessing needs and requirements at 6.5 TeV. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles.

  7. CMB-lensing beyond the Born approximation

    CERN Document Server

    Marozzi, Giovanni; Di Dio, Enea; Durrer, Ruth

    2016-01-01

    We investigate the weak lensing corrections to the cosmic microwave background temperature anisotropies considering effects beyond the Born approximation. To this aim, we use the small deflection angle approximation, to connect the lensed and unlensed power spectra, via expressions for the deflection angles up to third order in the gravitational potential. While the small deflection angle approximation has the drawback to be reliable only for multipoles $\\ell\\lesssim 2500$, it allows us to consistently take into account the non-Gaussian nature of cosmological perturbation theory beyond the linear level. The contribution to the lensed temperature power spectrum coming from the non-Gaussian nature of the deflection angle at higher order is a new effect which has not been taken into account in the literature so far. It turns out to be the leading contribution among the post-Born lensing corrections. On the other hand, the effect is smaller than corrections coming from non-linearities in the matter power spectrum...

  8. Contrast sensitivity evaluation of aspheric and spherical intraocular lenses 2 years after implantation.

    Science.gov (United States)

    Caporossi, Aldo; Casprini, Fabrizio; Martone, Gianluca; Balestrazzi, Angelo; Tosi, Gian Marco; Ciompi, Leonardo

    2009-07-01

    To compare the quality of vision with aspheric and spherical intraocular lenses (IOLs) in pseudophakic patients after long-term follow-up. Two hundred eyes of 100 patients with bilateral cataracts were randomly assigned to receive spherical (Acrysof SN60AT [Alcon Laboratories Inc] or Sensar AR40e [Advanced Medical Optics Inc]) or aspheric IOLs (Acrysof SN60WF [Alcon] or Tecnis Z9000 [Advanced Medical Optics]). Ophthalmologic examination, including best spectacle-corrected visual acuity (BSCVA), pupil size, ocular dominance, contrast sensitivity under mesopic and photopic conditions, and wavefront analysis, was performed 2 months and 1 and 2 years after surgery. No statistically significant differences among the four groups in terms of age, pupil diameter, postoperative BSCVA, comeal spherical aberration, and posterior capsular opacification were noted. At all followup examinations, contrast sensitivity results showed no significant differences between the two aspheric IOLs at all spatial frequencies. Under photopic conditions, significant differences (P<.05) between spherical and aspheric IOLs were detected for spatial frequencies of 12 and 18 cycles per degree (cpd) at 2 months and 2 years and 12 cpd at 1 year. Under mesopic conditions, significant differences (P<.05) were detected between spherical and aspheric IOLs for all spatial frequencies at 2 months; all spatial frequencies except 18 cpd at 1 year; and spatial frequencies of 3, 12, and 18 cpd at 2 years. In addition, aspheric IOLs had statistical reductions in total spherical aberration at all follow-up examinations (P<.01). This study confirms that implantation of a modified aspheric IOL improves functional visual performance at 2 years postoperative.

  9. Influence of gravitational lensing on gravitational radiation

    Science.gov (United States)

    Zakharov, A.

    In a paper by Wang, Turner and Stebbins (PRL, Phys. Rev. Lett. 77 (1996) p.2875) an influence of gravitational lensing on increasing an estimated rate of gravitational radiation sources was considered. We show that the authors used the incorrect model for this case and thus they gave overestimated rate of possible events for possible sources of gravitational radiation for the advanced LIGO detector. We show also that if we would use a more correct model of gravitational lensing, one could conclude that more strong influence on increasing rate of estimated events of gravitational radiation for advanced LIGO detector could give gravitational lenses of galactic masses but not gravitational lenses of stellar masses as Wang et al. concluded. Moreover, binary gravitational lenses could give essential distortion of gravitational wave form template, especially gravitational wave template of periodic sources and the effect could be significant for templates of quasi-periodic sources which could be detected by a future gravitational wave space detector like LISA. Recently, the Galactic center was considered by Ruffa (ApJ, 1999) as a gravitational lens that focuses a gravitational wave energy to the Earth. The author used the wave optic approximation to solve this problem and concluded that amplification due to the gravitational lens focusing could be very huge. The conclusion is based on the perfect location of the gravitational wave source, namely the source lies very close to the line passing through the Earth and the gravitational lens (the Galactic Center), therefore the probability of the huge magnification of gravitational wave sources is negligible.

  10. Determination of injection molding process windows for optical lenses using response surface methodology.

    Science.gov (United States)

    Tsai, Kuo-Ming; Wang, He-Yi

    2014-08-20

    This study focuses on injection molding process window determination for obtaining optimal imaging optical properties, astigmatism, coma, and spherical aberration using plastic lenses. The Taguchi experimental method was first used to identify the optimized combination of parameters and significant factors affecting the imaging optical properties of the lens. Full factorial experiments were then implemented based on the significant factors to build the response surface models. The injection molding process windows for lenses with optimized optical properties were determined based on the surface models, and confirmation experiments were performed to verify their validity. The results indicated that the significant factors affecting the optical properties of lenses are mold temperature, melt temperature, and cooling time. According to experimental data for the significant factors, the oblique ovals for different optical properties on the injection molding process windows based on melt temperature and cooling time can be obtained using the curve fitting approach. The confirmation experiments revealed that the average errors for astigmatism, coma, and spherical aberration are 3.44%, 5.62%, and 5.69%, respectively. The results indicated that the process windows proposed are highly reliable.

  11. Full covariance of CMB and lensing reconstruction power spectra

    CERN Document Server

    Peloton, Julien; Lewis, Antony; Carron, Julien; Zahn, Oliver

    2016-01-01

    CMB and lensing reconstruction power spectra are powerful probes of cosmology. However they are correlated, since the CMB power spectra are lensed and the lensing reconstruction is constructed using CMB multipoles. We perform a full analysis of the auto- and cross-covariances, including polarization power spectra and minimum variance lensing estimators, and compare with simulations of idealized future CMB-S4 observations. Covariances sourced by fluctuations in the unlensed CMB and instrumental noise can largely be removed by using a realization-dependent subtraction of lensing reconstruction noise, leaving a relatively simple covariance model that is dominated by lensing-induced terms and well described by a small number of principal components. The correlations between the CMB and lensing power spectra will be detectable at the level of $\\sim 5\\sigma$ for a CMB-S4 mission, and neglecting those could underestimate some parameter error bars by several tens of percent. However we found that the inclusion of ext...

  12. Weak gravitational lensing with the Square Kilometre Array

    CERN Document Server

    Brown, M L; Camera, S; Harrison, I; Joachimi, B; Metcalf, R B; Pourtsidou, A; Takahashi, K; Zuntz, J A; Abdalla, F B; Bridle, S; Jarvis, M; Kitching, T D; Miller, L; Patel, P

    2015-01-01

    We investigate the capabilities of various stages of the SKA to perform world-leading weak gravitational lensing surveys. We outline a way forward to develop the tools needed for pursuing weak lensing in the radio band. We identify the key analysis challenges and the key pathfinder experiments that will allow us to address them in the run up to the SKA. We identify and summarize the unique and potentially very powerful aspects of radio weak lensing surveys, facilitated by the SKA, that can solve major challenges in the field of weak lensing. These include the use of polarization and rotational velocity information to control intrinsic alignments, and the new area of weak lensing using intensity mapping experiments. We show how the SKA lensing surveys will both complement and enhance corresponding efforts in the optical wavebands through cross-correlation techniques and by way of extending the reach of weak lensing to high redshift.

  13. Practitioners’ opinions on the presentation of ocular pathology and ametropia in patients wearing ready-made reading spectacles

    Directory of Open Access Journals (Sweden)

    K. C. Phillips

    2008-01-01

    Full Text Available This paper presents the findings of a study to determine optometrists’ opinions on the presentation of ocular pathology and ametropia in patients wearing ready-made reading spectacles. Ninety-seven optometrists completed a questionnaire pertaining to ametropia and ocular diseases among these patients. The questionnaire contained information regarding patient demographics, ocular pathology, ocular ametropia and the regulatory and public health aspects of ready-made readers.Ninety-five percent of respondents stated that they had seen patients with ready-made readers in their practice and 62% of these stated that they had found the presence of ocular pathology in these patients. The pathologies most commonly reported as seen by practitioners were dry eye (86% of practitioners, cataracts (80% and diabetic retinopathy (54%. In addition, 39% of practitioners reported seeing patients with anisometropia. The majority of practitioners (71% stated that they sold ready-made readers in their practice. Sixty-three percentof practitioners indicated that they would be prepared to offer a service whereby a reduced consultation fee and a pair of ready-made readers could be incorporated into an indigent “package”. An overwhelming 88% of the practitioners felt that the sale of ready-made readers should be more regulated and 74% of practitioners felt that the Professional Board for Optometry and Dispensing Opticians should be responsible for monitoring their sale. The research suggests that wearers of ready-made readers should be screened for ocular pathology, reduced visual acuity and amblyopia. Current regulations should be tightened and a public awareness education campaign should be initiated. The use of ready-made reading spectacles, in deference to an eye examination by an optometrist, appears to be largely as a result of the perceived costs of pri-vate practice combined with ignorance and apathy

  14. Recycling of Plastic

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund; Fruergaard, Thilde

    2011-01-01

    Plastic is produced from fossil oil. Plastic is used for many different products. Some plastic products like, for example, wrapping foil, bags and disposable containers for food and beverage have very short lifetimes and thus constitute a major fraction of most waste. Other plastic products like......, for example, gutters, window frames, car parts and transportation boxes have long lifetimes and thus appear as waste only many years after they have been introduced on the market. Plastic is constantly being used for new products because of its attractive material properties: relatively cheap, easy to form......, good strength and long durability. Recycling of plastic waste from production is well-established, while recycling of postconsumer plastic waste still is in its infancy. This chapter describes briefly how plastic is produced and how waste plastic is recycled in the industry. Quality requirements...

  15. UVA Light-mediated Ascorbate Oxidation in Human Lenses.

    Science.gov (United States)

    Rakete, Stefan; Nagaraj, Ram H

    2017-01-13

    Whether ascorbate oxidation is promoted by UVA light in human lenses and whether this process is influenced by age and GSH levels are not known. In this study, we used paired lenses from human donors. One lens of each pair was exposed to UVA light, whereas the other lens was kept in the dark for the same period of time as the control. Using LC-MS/MS analyses, we found that older lenses (41-73 years) were more susceptible to UVA-induced ascorbate oxidation than younger lenses (18-40 years). Approximately 36% of the ascorbate (relative to control) was oxidized in older lenses compared to ~16% in younger lenses. Furthermore, lenses with higher levels of GSH were less susceptible to UVA-induced ascorbate oxidation compared to those with lower levels, and this effect was not dependent on age. The oxidation of ascorbate led to elevated levels of reactive α-dicarbonyl compounds. In summary, our study showed that UVA light exposure leads to ascorbate oxidation in human lenses and that such oxidation is more pronounced in aged lenses and is inversely related to GSH levels. Our findings suggest that UVA light exposure could lead to protein aggregation through ascorbate oxidation in human lenses.

  16. Interferometric Plasmonic Lensing with Nanohole Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yu; Joly, Alan G.; El-Khoury, Patrick Z.; Hess, Wayne P.

    2014-12-18

    Nonlinear photoemission electron microscopy (PEEM) of nanohole arrays in gold films maps propagating surface plasmons (PSPs) launched from lithographically patterned structures. Strong near field photoemission patterns are observed in the PEEM images, recorded following low angle of incidence irradiation of nanohole arrays with sub-15 fs laser pulses centered at 780 nm. The recorded photoemission patterns are attributed to constructive and destructive interferences between PSPs launched from the individual nanoholes which comprise the array. By exploiting the wave nature of PSPs, we demonstrate how varying the array geometry (hole diameter, pitch, and number of rows/columns) ultimately yields intense localized photoemission. Through a combination of PEEM and finite-difference time-domain simulations, we identify the optimal array geometry for efficient light coupling and interferometric plasmonic lensing. We show a preliminary application of inteferometric plasmonic lensing by enhancing the photoemission from the vertex of a gold triangle using nanohole array.

  17. Distance Duality Relation from Strong Gravitational Lensing

    CERN Document Server

    Liao, Kai; Cao, Shuo; Biesiada, Marek; Zheng, Xiaogang; Zhu, Zong-Hong

    2015-01-01

    Under very general assumptions of metric theory of spacetime, photons traveling along null geodesics and photon number conservation, two observable concepts of cosmic distance, i.e. the angular diameter and the luminosity distances are related to each other by the so called distance duality relation (DDR) $D^L=D^A(1+z)^2$. Observational validation of this relation is quite important because any evidence of its violation could be a signal of new physics. In this letter we introduce a new method to test DDR based on strong gravitational lensing systems and supernovae Ia. Using a new compilation of strong lensing systems and JLA compilation of SNe Ia we found no evidence of DDR violation. However, not so much the final result but the method itself is worth attention, because unlike previously proposed techniques, it does not depend on prior assumptions concerning the details of cosmological model and galaxy cluster modelling.

  18. Regular phantom black holes as gravitational lenses

    CERN Document Server

    Eiroa, Ernesto F

    2015-01-01

    The distortion of the spacetime structure in the surroundings of black holes affects the trajectories of light rays. As a consequence, black holes can act as gravitational lenses. Observations of type Ia supernovas, show that our Universe is in accelerated expansion. The usual explanation is that the Universe is filled with a negative pressure fluid called dark energy, which accounts for 70 % of its total density, which can be modeled by a self-interacting scalar field with a potential. We consider a class of spherically symmetric regular phantom black holes as gravitational lenses. We study large deflection angles, using the strong deflection limit, corresponding to an asymptotic logarithmic approximation. In this case, photons passing close to the photon sphere of the black hole experiment several loops around it before they emerge towards the observer, giving place to two infinite sets of relativistic images. Within this limit, we find analytical expressions for the positions and the magnifications of thes...

  19. Atmospheric dispersion effects in weak lensing measurements

    CERN Document Server

    Plazas, Andrés A

    2012-01-01

    The wavelength dependence of atmospheric refraction causes elongation of finite-bandwidth images along the elevation vector, which produces spurious signals in weak gravitational lensing shear measurements unless this atmospheric dispersion is calibrated and removed to high precision. Because astrometric solutions and point spread function (PSF) characteristics are typically calibrated from stellar images, differences between the reference stars' spectra and the galaxies' spectra will leave residual errors in both the astrometric positions ($\\Delta{\\bar{R}}$) and in the second moment (width) of the wavelength-averaged PSF ($\\Delta{v}$) for galaxies. We estimate the level of $\\Delta{V}$ that will induce spurious weak lensing signals in PSF-corrected galaxy shapes that exceed the statistical errors of the {\\em Dark Energy Survey (DES)} and the {\\em Large Synoptic Survey Telescope (LSST)} cosmic-shear experiments. We also estimate the $\\Delta{\\bar{R}}$ signals that will produce unacceptable spurious distortions ...

  20. Masses of galaxy clusters from gravitational lensing

    CERN Document Server

    Hoekstra, Henk; Dahle, Haakon; Israel, Holger; Limousin, Marceau; Meneghetti, Massimo

    2013-01-01

    Despite consistent progress in numerical simulations, the observable properties of galaxy clusters are difficult to predict ab initio. It is therefore important to compare both theoretical and observational results to a direct measure of the cluster mass. This can be done by measuring the gravitational lensing effects caused by the bending of light by the cluster mass distribution. In this review we discuss how this phenomenon can be used to determine cluster masses and study the mass distribution itself. As sample sizes increase, the accuracy of the weak lensing mass estimates needs to improve accordingly. We discuss the main practical aspects of these measurements. We review a number of applications and highlight some recent results.

  1. Can weak lensing surveys confirm BICEP2 ?

    CERN Document Server

    Chisari, Nora Elisa; Schmidt, Fabian

    2014-01-01

    The detection of B-modes in the Cosmic Microwave Background (CMB) polarization by the BICEP2 experiment, if interpreted as evidence for a primordial gravitational wave background, has enormous ramifications for cosmology and physics. It is crucial to test this hypothesis with independent measurements. A gravitational wave background leads to B-modes in galaxy shape correlations (shear) both through lensing and tidal alignment effects. Since the systematics and foregrounds of galaxy shapes and CMB polarization are entirely different, a detection of a cross-correlation between the two observables would provide conclusive proof for the existence of a primordial gravitational wave background. We find that upcoming weak lensing surveys will be able to detect the cross-correlation between B-modes of the CMB and galaxy shapes. However, this detection is not sufficient to confirm or falsify the hypothesis of a primordial origin for CMB B-mode polarization.

  2. Lensing Reconstruction using redshifted 21cm Fluctuations

    CERN Document Server

    Zahn, O; Zahn, Oliver; Zaldarriaga, Matias

    2005-01-01

    We investigate the potential of second generation measurements of redshifted 21 cm radiation from the epoch of reionization (EOR) to reconstruct the matter density fluctuations along the line of sight. To do so we generalize the quadratic methods developed for the Cosmic Microwave Background (CMB) to 21cm fluctuations. The three dimensional signal can be analyzed into a finite number of line of sight Fourier modes that contribute to the lensing reconstruction. In comparison with reconstruction using the CMB, 21cm fluctuations have a disadvantage of relative featurelessness, which can be compensated for by the fact that there are multiple uncorrelated backgrounds. The multiple redshift information allows to reconstruct relatively small scales even if one is limited by angular resolution. We estimate that a square kilometer of collecting area is needed with a maximal baseline of 3 km to achieve lensing reconstruction noise levels an order of magnitude below CMB quadratic estimator constraints at $l=1000$, and c...

  3. Stationary SMS lenses for concentrating photovoltaics

    Science.gov (United States)

    Kotsidas, Panagiotis; Chatzi, Eleni; Modi, Vijay

    2010-08-01

    This paper presents a novel approach regarding the design of stationary, non imaging, refractive lenses with high acceptance angles. A lens lies on a stationary aperture and as the sun moves throughout the day, the concentrated focal spot is tracked by a moving solar cell. The purpose of this work is to replace the 2-axis tracking of the sun with internal motion of the miniaturized solar cell inside the module. We show families of linear lenses with wide acceptance angles 60. and 30. achieving moderate concentrations of 10 - 30 suns. The lens is designed with a variation of the simultaneous multiple surface (SMS) technique which is combined with a genetic algorithm to optimize the free variables of the problem.

  4. Optical lenses and magnification in archery*

    Directory of Open Access Journals (Sweden)

    B. Strydom

    2010-12-01

    Full Text Available The use of optical lenses to increase or magnify a target of concern is commonly used in compound bow archery.  The principles and factors that may influence the use of these lenses may, however, not be fully understood by archers.  Two types of lens systems, the one-lens system and the two-lens system, as described by the authors, may be used. Different factors such as the draw length of the archer,the ametropic condition of the archer, depth of field, depth of focus, age, accommodation, the power of F1 and F2 (see Figures 1 and 2 in the paper and the distance the lens is placed from the archer may influence the results of the lens used by the archer. (S Afr Optom 2010 69(1 29-34

  5. Precision cluster mass determination from weak lensing

    CERN Document Server

    Mandelbaum, Rachel; Baldauf, Tobias; Smith, Robert E

    2009-01-01

    Weak gravitational lensing has been used extensively in the past decade to constrain the masses of galaxy clusters, and is the most promising observational technique for providing the mass calibration necessary for precision cosmology with clusters. There are several challenges in estimating cluster masses, particularly (a) the sensitivity to astrophysical effects and observational systematics that modify the signal relative to the theoretical expectations, and (b) biases that can arise due to assumptions in the mass estimation method, such as the assumed radial profile of the cluster. All of these challenges are more problematic in the inner regions of the cluster, suggesting that their influence would ideally be suppressed for the purpose of mass estimation. However, at any given radius the differential surface density measured by lensing is sensitive to all mass within that radius, and the corrupted signal from the inner parts is spread out to all scales. We develop a new statistic that is ideal for estima...

  6. Strong gravitational lensing and dark energy complementarity

    Energy Technology Data Exchange (ETDEWEB)

    Linder, Eric V.

    2004-01-21

    In the search for the nature of dark energy most cosmological probes measure simple functions of the expansion rate. While powerful, these all involve roughly the same dependence on the dark energy equation of state parameters, with anticorrelation between its present value w{sub 0} and time variation w{sub a}. Quantities that have instead positive correlation and so a sensitivity direction largely orthogonal to, e.g., distance probes offer the hope of achieving tight constraints through complementarity. Such quantities are found in strong gravitational lensing observations of image separations and time delays. While degeneracy between cosmological parameters prevents full complementarity, strong lensing measurements to 1 percent accuracy can improve equation of state characterization by 15-50 percent. Next generation surveys should provide data on roughly 105 lens systems, though systematic errors will remain challenging.

  7. Direct Shear Mapping: Prospects for weak lensing studies of individual galaxy-galaxy lensing systems

    CERN Document Server

    de Burgh-Day, Catherine O; Webster, Rachel L; Hopkins, Andrew M

    2015-01-01

    We have investigated, using both a theoretical and an empirical approach, the frequency of low redshift galaxy-galaxy lensing systems in which the signature of weak lensing might be directly detectable. We find good agreement between these two approaches. In order to make a theoretical estimate of the weak lensing shear, $\\gamma$, for each galaxy in a catalogue, we have made an estimate of the asymptotic circular velocity from the stellar mass using three different approaches: from a simulation based relation, from an empirically-derived relation, and using the baryonic Tully-Fisher relation. Using data from the Galaxy and Mass Assembly redshift survey we estimate the frequency of detectable weak lensing at low redshift. We find that to a redshift of $z\\sim 0.6$, the probability of a galaxy being weakly lensed by at least $\\gamma = 0.02$ is $\\sim 0.01$. A scatter in the $M_*-M_h$ relation results in a shift towards higher measured shears for a given population of galaxies. Given this, and the good probability...

  8. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    CERN Document Server

    Kirk, D; Benoit-Lévy, A; Cawthon, R; Chang, C; Larsen, P; Amara, A; Bacon, D; Crawford, T M; Dodelson, S; Fosalba, P; Giannantonio, T; Holder, G; Jain, B; Kacprzak, T; Lahav, O; MacCrann, N; Nicola, A; Refregier, A; Sheldon, E; Story, K T; Troxel, M A; Vieira, J D; Vikram, V; Zuntz, J; Abbott, T M C; Abdalla, F B; Becker, M R; Benson, B A; Bernstein, G M; Bernstein, R A; Bleem, L E; Bonnett, C; Bridle, S L; Brooks, D; Buckley-Geer, E; Burke, D L; Capozzi, D; Carlstrom, J E; Rosell, A Carnero; Kind, M Carrasco; Carretero, J; Crocce, M; Cunha, C E; D'Andrea, C B; da Costa, L N; Desai, S; Diehl, H T; Dietrich, J P; Doel, P; Eifler, T F; Evrard, A E; Flaugher, B; Frieman, J; Gerdes, D W; Goldstein, D A; Gruen, D; Gruendl, R A; Honscheid, K; James, D J; Jarvis, M; Kent, S; Kuehn, K; Kuropatkin, N; Lima, M; March, M; Martini, P; Melchior, P; Miller, C J; Miquel, R; Nichol, R C; Ogando, R; Plazas, A A; Reichardt, C L; Roodman, A; Rozo, E; Rykoff, E S; Sako, M; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla-Noarbe, I; Simard, G; Smith, R C; Soares-Santos, M; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thomas, D; Wechsler, R H; Weller, J

    2015-01-01

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ re...

  9. Systematic errors in weak lensing: application to SDSS galaxy-galaxy weak lensing

    CERN Document Server

    Mandelbaum, R; Seljak, U; Guzik, J; Padmanabhan, N; Blake, C; Blanton, M R; Lupton, R; Brinkmann, J; Mandelbaum, Rachel; Hirata, Christopher M.; Seljak, Uros; Guzik, Jacek; Padmanabhan, Nikhil; Blake, Cullen; Blanton, Michael R.; Lupton, Robert; Brinkmann, Jonathan

    2005-01-01

    Weak lensing is emerging as a powerful observational tool to constrain cosmological models, but is at present limited by an incomplete understanding of many sources of systematic error. Many of these errors are multiplicative and depend on the population of background galaxies. We show how the commonly cited geometric test, which is rather insensitive to cosmology, can be used as a ratio test of systematics in the lensing signal at the 1 per cent level. We apply this test to the galaxy-galaxy lensing analysis of the Sloan Digital Sky Survey (SDSS), which at present is the sample with the highest weak lensing signal to noise and has the additional advantage of spectroscopic redshifts for lenses. This allows one to perform meaningful geometric tests of systematics for different subsamples of galaxies at different mean redshifts, such as brighter galaxies, fainter galaxies and high-redshift luminous red galaxies, both with and without photometric redshift estimates. We use overlapping objects between SDSS and th...

  10. Weak Lensing On the Celestial Sphere

    OpenAIRE

    Stebbins, Albert

    1996-01-01

    This paper details a description of the pattern of galaxy image distortion over the entire sky caused by the gravitational lensing which is the result of large scale inhomogeneities in our universe. We present a tensor spherical harmonic formalism to describe this pattern, giving many useful formulae. This is applied to density inhomogeneities, where we compute the angular power spectrum of the shear pattern, as well as the noise properties due to finite galaxy sampling and cosmic variance. W...

  11. Terahertz lenses based on nonuniform metasurfaces

    Science.gov (United States)

    Wang, Zhengbin; Chen, Jinchang; Xue, Manlin

    2015-03-01

    Nonuniform metasurfaces with varying dielectric thicknesses are introduced to full control the transmitted wavefront. Two-port network model is used to analyze the phase shifts of the transmitted field going through dielectric elements. Then, two terahertz convex lenses are designed by using nonuniform polyimide metasurfaces to realize the required abrupt phase distributions. Full-wave simulations demonstrate their excellent performances in controlling the transmitted waves.

  12. Gravitational lensing of wormholes in noncommutative geometry

    CERN Document Server

    Kuhfittig, Peter K F

    2015-01-01

    It has been shown that a noncommutative-geometry background may be able to support traversable wormholes. This paper discusses the possible detection of such wormholes in the outer regions of galactic halos by means of gravitational lensing. The procedure allows a comparison to other models such as the NFW model and f(R) modified gravity and is likely to favor a model based on noncommutative geometry.

  13. SimpLens: Interactive gravitational lensing simulator

    Science.gov (United States)

    Saha, Prasenjit; Williams, Liliya L. R.

    2016-06-01

    SimpLens illustrates some of the theoretical ideas important in gravitational lensing in an interactive way. After setting parameters for elliptical mass distribution and external mass, SimpLens displays the mass profile and source position, the lens potential and image locations, and indicate the image magnifications and contours of virtual light-travel time. A lens profile can be made shallower or steeper with little change in the image positions and with only total magnification affected.

  14. Automation Enhancement of Multilayer Laue Lenses

    Energy Technology Data Exchange (ETDEWEB)

    Lauer K. R.; Conley R.

    2010-12-01

    X-ray optics fabrication at Brookhaven National Laboratory has been facilitated by a new, state of the art magnetron sputtering physical deposition system. With its nine magnetron sputtering cathodes and substrate carrier that moves on a linear rail via a UHV brushless linear servo motor, the system is capable of accurately depositing the many thousands of layers necessary for multilayer Laue lenses. I have engineered a versatile and automated control program from scratch for the base system and many subsystems. Its main features include a custom scripting language, a fully customizable graphical user interface, wireless and remote control, and a terminal-based interface. This control system has already been successfully used in the creation of many types of x-ray optics, including several thousand layer multilayer Laue lenses.Before reaching the point at which a deposition can be run, stencil-like masks for the sputtering cathodes must be created to ensure the proper distribution of sputtered atoms. Quality of multilayer Laue lenses can also be difficult to measure, given the size of the thin film layers. I employ my knowledge of software and algorithms to further ease these previously painstaking processes with custom programs. Additionally, I will give an overview of an x-ray optic simulator package I helped develop during the summer of 2010. In the interest of keeping my software free and open, I have worked mostly with the multiplatform Python and the PyQt application framework, utilizing C and C++ where necessary.

  15. The Origin of Weak Lensing Convergence Peaks

    CERN Document Server

    Liu, Jia

    2016-01-01

    Weak lensing convergence peaks are a promising tool to probe nonlinear structure evolution at late times, providing additional cosmological information beyond second-order statistics. Previous theoretical and observational studies have shown that the cosmological constraints on $\\Omega_m$ and $\\sigma_8$ are improved by a factor of up to ~ 2 when peak counts and second-order statistics are combined, compared to using the latter alone. We study the origin of lensing peaks using observational data from the 154 deg$^2$ Canada-France-Hawaii Telescope Lensing Survey. We found that while high peaks (with height $\\kappa$ >3.5 $\\sigma_\\kappa$, where $\\sigma_\\kappa$ is the r.m.s. of the convergence $\\kappa$) are typically due to one single massive halo of ~$10^{15}M_\\odot$, low peaks ($\\kappa$ ~ their virial radii), compared with ~0.25 virial radii for halos linked with high peaks, hinting that low peaks are more immune to baryonic processes whose impact is confined to the inner regions of the dark matter halos. Our fi...

  16. Three QSOs acting as strong gravitational lenses

    CERN Document Server

    Courbin, F; Djorgovski, S G; Rerat, F; Tewes, M; Meylan, G; Stern, D; Mahabal, A; Boroson, T; Dheeraj, R; Sluse, D

    2011-01-01

    We report the discovery of three new cases of QSOs acting as strong gravitational lenses on background emission line galaxies: SDSS J0827+5224 (zQSO = 0.293, zs = 0.412), SDSS J0919+2720 (zQSO = 0.209, zs = 0.558), SDSS J1005+4016 (zQSO = 0.230, zs = 0.441). The selection was carried out using a sample of 22,298 SDSS spectra displaying at least four emission lines at a redshift beyond that of the foreground QSO. The lensing nature is confirmed from Keck imaging and spectroscopy, as well as from HST/WFC3 imaging in the F475W and F814W filters. Two of the QSOs have face-on spiral host galaxies and the third is a QSO+galaxy pair. The velocity dispersion of the host galaxies, inferred from simple lens modeling, is between \\sigma_v = 210 and 285 km/s, making these host galaxies comparable in mass with the SLACS sample of early-type strong lenses.

  17. Compact Groups analysis using weak gravitational lensing

    Science.gov (United States)

    Chalela, Martín; Johana Gonzalez, Elizabeth; Garcia Lambas, Diego; Foëx, Gael

    2017-01-01

    We present a weak lensing analysis of a sample of SDSS Compact Groups (CGs). Using the measured radial density contrast profile, we derive the average masses under the assumption of spherical symmetry, obtaining a velocity dispersion for the Singular Isothermal Spherical model, σV = 270 ± 40 km s-1, and for the NFW model, R_{200}=0.53± 0.10 h_{70}^{-1}Mpc. We test three different definitions of CGs centres to identify which best traces the true dark matter halo centre, concluding that a luminosity weighted centre is the most suitable choice. We also study the lensing signal dependence on CGs physical radius, group surface brightness, and morphological mixing. We find that groups with more concentrated galaxy members show steeper mass profiles and larger velocity dispersions. We argue that both, a possible lower fraction of interloper and a true steeper profile, could be playing a role in this effect. Straightforward velocity dispersion estimates from member spectroscopy yields σV ≈ 230 km s-1 in agreement with our lensing results.

  18. The CASTLES Imaging Survey of Gravitational Lenses

    Science.gov (United States)

    Peng, C. Y.; Falco, E. E.; Lehar, J.; Impey, C. D.; Kochanek, C. S.; McLeod, B. A.; Rix, H.-W.

    1997-12-01

    The CASTLES survey (Cfa-Arizona-(H)ST-Lens-Survey) is imaging most known small-separation gravitational lenses (or lens candidates), using the NICMOS camera (mostly H-band) and the WFPC2 (V and I band) on HST. To date nearly half of the IR imaging survey has been completed. The main goals are: (1) to search for lens galaxies where none have been directly detected so far; (2) obtain photometric redshift estimates (VIH) for the lenses where no spectroscopic redshifts exist; (3) study and model the lens galaxies in detail, in part to study the mass distribution within them, in part to identify ``simple" systems that may permit accurate time delay estimates for H_0; (3) measure the M/L evolution of the sample of lens galaxies with look-back time (to z ~ 1); (4) determine directly which fraction of sources are lensed by ellipticals vs. spirals. We will present the survey specifications and the images obtained so far.

  19. Quadrupole Focusing Lenses for Charged Particles

    Energy Technology Data Exchange (ETDEWEB)

    Cork, Bruce; Zajec, Emery

    1953-04-15

    A set of four strong focusing magnetic quadrupole lenses has been constructed and operated. Each lens consists of four air cooled electromagnets with pole tips having a hyperbolic cross section. Each lens is 4 in. long and has an aperture 2 in. in diameter. Measurements of the magnetic field demonstrate that the hyperbolic cross section satisfies the requirements of a constant magnetic field gradient very well. The technique of deflecting a current carrying flexible wire has been used to measure the trajectory of charged particles through the system of lenses. It has been observed that the strong focusing requirements are satisfied. The system of lenses was then used to focus 0.5 Mev protons, 20 Mev deuterons, and 40 Mev alpha particles. The parallel beam of 0.5 Mev protons was detected by observing the incandescence of a quartz plate while the protons were bombarding it. The focused beam was less than 1 mm in diameter. The astigmatic 20 Mev deuteron beam from the 60 in. cyclotron was increased in current density by a factor greater than 30.

  20. Electron lenses for the large hadron collider

    CERN Document Server

    Stancari†, G; Bruce, R; Redaelli, S; Rossi, A; Salvachua Ferrando, B

    2014-01-01

    Electron lenses are pulsed, magnetically confined electron beamswhose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-bybunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beamcompensation, and for the demonstration of halo scrapingwith hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in RHIC at BNL. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, hollow electron beam collimation was studied as an option to complement the collimation system for the LHC upgrades. A conceptual design was recently completed, and the project is moving towards a technical design in 2014–2015 for construction in 2015–2017, if needed, after resuming LHC operations and re-assessing collimation needs and requirements at 6.5 TeV. Because of the...

  1. 77 FR 54930 - Carlyle Plastics and Resins, Formerly Known as Fortis Plastics, A Subsidiary of Plastics...

    Science.gov (United States)

    2012-09-06

    ... Employment and Training Administration Carlyle Plastics and Resins, Formerly Known as Fortis Plastics, A... plastic parts. New information shows that Fortis Plastics is now called Carlyle Plastics and Resins. In... of Carlyle Plastics and Resins, formerly known as Fortis Plastics, a subsidiary of...

  2. Wetting angles of rigid contact lens plastics: the effect of contact lens wear.

    Science.gov (United States)

    Poster, M G; Gelfer, D M; Fernandez, N M

    1986-06-01

    Several adapted rigid contact lens wearers were given duplicates of their present lenses made in different plastics. They were required to wear each material on each eye for a period of four hours. Both the average wetting angle and its range of values for each material was compiled. All lenses tended to give similar average wetting angles but ranges of angles for the PMMA/siloxanyl materials were greater than that for PMMA and GP IITM. Both values should be utilized when evaluating the wettability of a specific material.

  3. Cosmological Parameters from Multiple-arc Gravitational Lensing Systems; 1, smooth lensing potentials

    CERN Document Server

    Link, R; Link, Robert; Pierce, Michael J.

    1998-01-01

    We describe a new approach for the determination of cosmological parameters using gravitational lensing systems with multiple arcs, exploiting the fact that a given cluster can produce multiple arcs from sources over a broad range in redshift. The coupling between the critical radius of a single arc and the projected mass density of the lensing cluster can be avoided by considering the relative positions of two or more arcs. Cosmological sensitivity appears through the angular size-redshift relation. We consider simulated data constructed using a more general form for the potential, realistic sources, and an assumed cosmology and present a method for simultaneously inverting the lens and extracting the cosmological parameters. The input data required are the image and measured redshifts for the arcs. The technique relies upon the conservation of surface brightness in gravitationally lensed systems. We find that for a simple lens model our approach can recover the cosmological parameters assumed in the constru...

  4. [Intraocular lenses for the correction of refraction errors. Part 1: phakic anterior chamber lenses].

    Science.gov (United States)

    Kohnen, T; Baumeister, M; Cichocki, M

    2005-10-01

    In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.

  5. Weak lensing power spectra for precision cosmology: Multiple-deflection, reduced shear and lensing bias corrections

    CERN Document Server

    Krause, Elisabeth

    2009-01-01

    It is usually assumed that the ellipticity power spectrum measured in weak lensing observations can be expressed as an integral over the underlying matter power spectrum. This is true at second order in the gravitational potential. We extend the standard calculation, constructing all corrections to fourth order in the gravitational potential. There are four types of corrections: corrections to the lensing shear due to multiple-deflections; corrections due to the fact that shape distortions probe the reduced shear $\\gamma/(1-\\kappa)$ rather than the shear itself; corrections associated with the non-linear conversion of reduced shear to mean ellipticity; and corrections due to the fact that observational galaxy selection and shear measurement is based on galaxy brightnesses and sizes which have been (de)magnified by lensing. We show how the previously considered corrections to the shear power spectrum correspond to terms in our analysis, and highlight new terms that were not previously identified. All correctio...

  6. The influence of year, laying date, egg fertility and incubation, individual hen, hen age and mass and clutch size on maternal immunoglobulin Y concentration in captive Steller's and spectacled eider egg yolk.

    Science.gov (United States)

    Counihan, Katrina L; Maniscalco, John M; Bozza, Maryann; Hendon, Jill M; Hollmén, Tuula E

    2015-09-01

    Steller's eiders and spectacled eiders are sea duck species whose populations have declined significantly and infectious diseases could influence offspring survival. Therefore, the maternal transfer of immunoglobulin Y (IgY) into yolk was investigated in captive Steller's and spectacled eiders during the 2007-2013 breeding seasons. This project had two objectives: establish baseline IgY levels in Steller's and spectacled eider yolk under controlled captive conditions and evaluate the effect of year, laying date, egg fertility, egg incubation duration, individual hen, hen age and mass, and laying order to determine which variables influenced IgY levels. Average IgY concentrations were 0.03-0.48 mg ml(-1) in Steller's eider yolk and 0.10-0.51 mg ml(-1) in spectacled eider yolk. The year and individual hen influenced IgY concentration in Steller's and spectacled eider yolk. The laying date was negatively correlated with egg IgY levels for most Steller's eider hens, but laying order was positively correlated with egg IgY concentration for spectacled eiders.

  7. Depth of focus increase by multiplexing programmable diffractive lenses.

    Science.gov (United States)

    Iemmi, C; Campos, J; Escalera, J C; López-Coronado, O; Gimeno, R; Yzuel, M J

    2006-10-30

    A combination of several diffractive lenses written onto a single programmable liquid crystal display (LCD) is proposed for increasing the Depth of Focus (DOF) of the imaging system as a whole. The lenses are spatially multiplexed in a random scheme onto the LCD. The axial irradiance distribution produced by each lens overlaps with the next one producing an extended focal depth. To compare the image quality of the multiplexed lenses, the Modulation Transfer Function (MTF) is calculated. Finally we obtain the experimental Point Spread Functions (PSF) for these multiplexed lenses and experimental results in which an extended object is illuminated under spatially incoherent monochromatic light. We compare the images obtained in the focal plane and in some defocused planes with the single lens and with three multiplexed lenses. The experimental results confirm that the multiplexed lenses produce a high increase in the depth of focus.

  8. Constraints on cosmological models from strong gravitational lensing systems

    CERN Document Server

    Cao, Shuo; Biesiada, Marek; Godlowski, Wlodzimierz; Zhu, Zong-Hong

    2011-01-01

    Using the gravitational lensing theory and cluster mass distribution model, we try to collect a relatively complete observational data concerning an Hubble constant independent ratio between two angular diameter distances $D_{ds}/D_s$ from various large systematic gravitational lens surveys and lensing by galaxy clusters combined with X-ray observations. On one hand, strongly gravitationally lensed quasar-galaxy systems create such a new opportunity by combining stellar kinematics (central velocity dispersion measurements) with lensing geometry (Einstein radius determination from position of images). We apply such a method to a combined gravitational lens data set including 27 data points from Sloan Lens ACS (SLACS), Lens Structure and Dynamics survey (LSD), and Sloan Bright Arcs Survey (SBAS). On the other hand, a new sample of 10 lensing galaxy clusters with redshifts ranging from 0.1 to 0.6 is also used, which is selected carefully from strong gravitational lensing systems with both X-ray satellite observa...

  9. Linkages between sea-ice coverage, pelagic-benthic coupling, and the distribution of spectacled eiders: Observations in March 2008, 2009 and 2010, northern Bering Sea

    Science.gov (United States)

    Cooper, L. W.; Sexson, M. G.; Grebmeier, J. M.; Gradinger, R.; Mordy, C. W.; Lovvorn, J. R.

    2013-10-01

    Icebreaker-based sampling in the northern Bering Sea south of St. Lawrence Island in March of 2008, 2009, and 2010 has provided new data on overall ecosystem function early in the annual productive cycle. While water-column chlorophyll concentrations (5 µM. These data, together with other physical, biological, and nutrient data, are presented here in conjunction with observed sea-ice dynamics and the distribution of an apex predator, the Spectacled Eider (Somateria fischeri). Sea-ice dynamics in addition to benthic food availability, as determined by sedimentation processes, play a role in the distribution of spectacled eiders, which cannot always access the greatest biomass of their preferred bivalve prey. Overall, the data and observations indicate that the northern Bering Sea is biologically active in late winter, but with strong atmospheric and hydrographic controls. These controls pre-determine nutrient and chlorophyll distributions, water-column mixing, as well as pelagic-benthic coupling.

  10. La mise en spectacle de la mort dans deux pièces du théâtre espagnol du Siècle d’Or

    OpenAIRE

    Odile Lasserre Dempure

    2013-01-01

    Dans Fuente Ovejuna (1613) de Lope de Vega et La serrana de la Vera (1613) de Luis Vélez de Guevara, la mort est spectacle. Cette mise en spectacle de la mort, qui doit être replacée dans le contexte d’une esthétique macabre caractéristique de la période baroque, s’articule sur de multiples réseaux de sens dont nous tentons de dégager quelques lignes directrices. Une lecture attentive de la façon dont la mort et le cadavre sont mis en scène permet de comprendre que pour l’imaginaire de l’époq...

  11. Our plastic age

    National Research Council Canada - National Science Library

    Richard C. Thompson; Shanna H. Swan; Charles J. Moore; Frederick S. vom Saal

    2009-01-01

    Within the last few decades, plastics have revolutionized our daily lives. Globally we use in excess of 260 million tonnes of plastic per annum, accounting for approximately 8 per cent of world oil production...

  12. Weinig plastic in vissenmaag

    NARCIS (Netherlands)

    Foekema, E.M.

    2012-01-01

    Waar de magen van sommige zeevogels vol plastic zitten, lijken vissen in de Noordzee nauwelijks last te hebben van kunststofafval. Onderzoekers die plastic resten zochten in vissenmagen vonden ze in elk geval nauwelijks.

  13. Ear Plastic Surgery

    Science.gov (United States)

    ... ENTCareers Marketplace Find an ENT Doctor Near You Ear Plastic Surgery Ear Plastic Surgery Patient Health Information ... they may improve appearance and self-confidence. Can Ear Deformities Be Corrected? Formation of the ear during ...

  14. Galaxy–Galaxy Weak-lensing Measurements from SDSS. I. Image Processing and Lensing Signals

    Science.gov (United States)

    Luo, Wentao; Yang, Xiaohu; Zhang, Jun; Tweed, Dylan; Fu, Liping; Mo, H. J.; van den Bosch, Frank C.; Shu, Chenggang; Li, Ran; Li, Nan; Liu, Xiangkun; Pan, Chuzhong; Wang, Yiran; Radovich, Mario

    2017-02-01

    We present our image processing pipeline that corrects the systematics introduced by the point-spread function (PSF). Using this pipeline, we processed Sloan Digital Sky Survey (SDSS) DR7 imaging data in r band and generated a galaxy catalog containing the shape information. Based on our shape measurements of the galaxy images from SDSS DR7, we extract the galaxy–galaxy (GG) lensing signals around foreground spectroscopic galaxies binned in different luminosities and stellar masses. We estimated the systematics, e.g., selection bias, PSF reconstruction bias, PSF dilution bias, shear responsivity bias, and noise rectification bias, which in total is between ‑9.1% and 20.8% at 2σ levels. The overall GG lensing signals we measured are in good agreement with Mandelbaum et al. The reduced χ 2 between the two measurements in different luminosity bins are from 0.43 to 0.83. Larger reduced χ 2 from 0.60 to 1.87 are seen for different stellar mass bins, which is mainly caused by the different stellar mass estimator. The results in this paper with higher signal-to-noise ratio are due to the larger survey area than SDSS DR4, confirming that more luminous/massive galaxies bear stronger GG lensing signals. We divide the foreground galaxies into red/blue and star-forming/quenched subsamples and measure their GG lensing signals. We find that, at a specific stellar mass/luminosity, the red/quenched galaxies have stronger GG lensing signals than their counterparts, especially at large radii. These GG lensing signals can be used to probe the galaxy–halo mass relations and their environmental dependences in the halo occupation or conditional luminosity function framework.

  15. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Science.gov (United States)

    Kirk, D.; Omori, Y.; Benoit-Lévy, A.; Cawthon, R.; Chang, C.; Larsen, P.; Amara, A.; Bacon, D.; Crawford, T. M.; Dodelson, S.; Fosalba, P.; Giannantonio, T.; Holder, G.; Jain, B.; Kacprzak, T.; Lahav, O.; MacCrann, N.; Nicola, A.; Refregier, A.; Sheldon, E.; Story, K. T.; Troxel, M. A.; Vieira, J. D.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Becker, M. R.; Benson, B. A.; Bernstein, G. M.; Bernstein, R. A.; Bleem, L. E.; Bonnett, C.; Bridle, S. L.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carlstrom, J. E.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Reichardt, C. L.; Roodman, A.; Rozo, E.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Simard, G.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Wechsler, R. H.; Weller, J.

    2016-06-01

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg2 of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of zmed ˜ 0.7, while the CMB lensing kernel is broad and peaks at z ˜ 2. The resulting cross-correlation is maximally sensitive to mass fluctuations at z ˜ 0.44. Assuming the Planck 2015 best-fitting cosmology, the amplitude of the DES×SPT cross-power is found to be ASPT = 0.88 ± 0.30 and that from DES×Planck to be APlanck = 0.86 ± 0.39, where A = 1 corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of 2.9σ and 2.2σ, respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photo-z uncertainty and CMB lensing systematics. We calculate a value of A = 1.08 ± 0.36 for DES×SPT when we correct the observations with a simple intrinsic alignment model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation. We provide forecasts for the expected signal-to-noise ratio of the combination of the five-year DES survey and SPT-3G.

  16. Biodegradability of Plastics

    OpenAIRE

    Yutaka Tokiwa; Calabia, Buenaventurada P.; Charles U. Ugwu; Seiichi Aiba

    2009-01-01

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical ...

  17. Recent experience with design and manufacture of cine lenses

    Science.gov (United States)

    Thorpe, Michael D.; Dalzell, Kristen E.

    2015-09-01

    Modern cine lenses require a high degree of aberration correction over a large and ever expanding image size. At low to medium volume production levels, these highly corrected designs also require a workable tolerance set and compensation scheme for successful manufacture. In this paper we discuss the design and manufacture of cine lenses with reference to current designs both internal and in the patent literature and some experience in design, tolerancing and manufacturing these lenses in medium volume production.

  18. Strong Lensing, dark matter and H_0 estimate

    OpenAIRE

    Tortora, C.

    2007-01-01

    Gravitational lensing represents a powerful tool to estimate the cosmological pa- rameters and the distribution of dark matter. I will describe the main observable quantities, concentrating on strong lensing, that manifests its effect through the formation of spectacular events, like multiple quasars, Einstein rings and arcs in clusters of galaxies. In events where a quasar is lensed by an intervening galaxy, it is possible to give an estimate of the Hubble constant H_0, by choosing a mass de...

  19. Experimental study of thermal lensing of Nd:YAG laser

    Institute of Scientific and Technical Information of China (English)

    HU Shao-yun; ZHONG Ming; ZUO Yan; FAN Hong-ying

    2006-01-01

    A wavefront method of measuring the thermal lensing of solid-state lasers is proposed.This method is easy to implement and has a high spatial resolution for diagnosing thermal lensing.By this method,the thermal lensing of Nd:YAG laser is studied in detail.And this work provides a means for studying the thermal effects of laser medium and many instructional parameters for optimizing the design of the laser cavity.

  20. La mise en spectacle de la mort dans deux pièces du théâtre espagnol du Siècle d’Or

    Directory of Open Access Journals (Sweden)

    Odile Lasserre Dempure

    2012-08-01

    Full Text Available Dans Fuente Ovejuna (1613 de Lope de Vega et La serrana de la Vera (1613 de Luis Vélez de Guevara, la mort est spectacle. Cette mise en spectacle de la mort, qui doit être replacée dans le contexte d’une esthétique macabre caractéristique de la période baroque, s’articule sur de multiples réseaux de sens dont nous tentons de dégager quelques lignes directrices. Une lecture attentive de la façon dont la mort et le cadavre sont mis en scène permet de comprendre que pour l’imaginaire de l’époque, cette mise en spectacle de la mort est surtout mise en spectacle de la vie. La mort, effroyable mais bienfaisante, est une mort génératrice de vie.En Fuente Ovejuna (1613, de Lope de Vega, y en La Serrana de la Vera (1613, de Luis Vélez de Guevara, la muerte es un espectáculo. Esta representación de la muerte, que debe ser situada en el contexto de una estética macabra propia al barroco, adquiere múltiples significados que trataremos de determinar y poner en relieve. Una lectura atenta de la manera cómo la muerte y el cadáver son expuestos, nos permite deducir que para el imaginario de la época esta representación de la muerte es más que nada una representación de la vida. La muerte, espantosa pero benéfica, es una muerte generadora de vida.

  1. Galaxy scale lenses in the RCS2: I. First catalog of candidate strong lenses

    CERN Document Server

    Anguita, T; Gladders, M D; Faure, C; Yee, H; Gilbank, D

    2012-01-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey (RCS2). The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 ~5.5x10e11 M_sun/h) and rich in dark matter (~14 M_sun/L_sun,B*h). Even though a slight increasing trend in the mass-to-light ratio is observed from z=0.2 to z=0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  2. Chemical Recycle of Plastics

    Directory of Open Access Journals (Sweden)

    Sara Fatima

    2014-11-01

    Full Text Available Various chemical processes currently prevalent in the chemical industry for plastics recycling have been discussed. Possible future scenarios in chemical recycling have also been discussed. Also analyzed are the effects on the environment, the risks, costs and benefits of PVC recycling. Also listed are the various types of plastics and which plastics are safe to use and which not after rcycle

  3. Plastic value chains

    DEFF Research Database (Denmark)

    Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

    2014-01-01

    Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example...

  4. Effects of lead structure in Bering Sea pack ice on the flight costs of wintering spectacled eiders

    Science.gov (United States)

    Bump, Joseph K.; Lovvorn, James R.

    2004-10-01

    In polar regions, sea ice is critical habitat for many marine birds and mammals. The quality of pack ice habitat depends on the duration and spacing of leads (openings in the ice), which determine access to water and air for diving endotherms, and how often and how far they must move as leads open and close. Recent warming trends have caused major changes in the extent and nature of sea ice at large scales used in climate models. However, no studies have analyzed lead structure in terms of habitat for ice-dependent endotherms, or effects of climate on ice habitat at scales relevant to their daily movements. Based on observations from an icebreaker and synthetic aperture radar (SAR) images, we developed methods to describe the dynamics and thermodynamics of lead structure relative to use by spectacled eiders ( Somateria fischeri) wintering in pack ice of the Bering Sea. By correlating lead structure with weather variables, we then used these methods to estimate changes in lead dynamics from 1945 to 2002, and effects of such changes on flight costs of the eiders. For 1991-1992, when images were available about every 3 days throughout winter, SAR images were divided among five weather regimes defined by wind speed, wind direction, and air temperature. Based on 12.5-m pixels, lead shape, compass orientation, and fetch across leads did not differ among the weather regimes. However, the five regimes differed in total area of open water, leads per unit area, and distance between leads. Lead duration was modeled based on air temperature, wind, and fetch. Estimates of mean daily flight time for eiders, based on lead duration and distance between neighboring leads, differed among regimes by 0 to 15 min. Resulting flight costs varied from 0 to 158 kJ day -1, or from 0% to 11% of estimated field metabolic rate. Over 57 winters (1945-2002), variation among years in mean daily flight time was most influenced by the north-south wind component, which determined pack divergence

  5. Understanding the IGM Through the Use of a Lensed Quasar

    Science.gov (United States)

    Panurach, Teresa; O'Dowd, Matthew

    2017-01-01

    Quasars are among the brightest objects in the universe. In rare gravitationally lensed quasars, their light is split and travels along multiple paths through an intervening lensing galaxy. The light that follows these different paths encounters various parts of the intergalactic medium (IGM) and may show different absorption features, indicating the varying composition of the IGM. By analyzing spectra from a gravitationally lensed quasar, B1422+231, observed by the Gemini North Telescope, we compare the absorption features identified in the lensed images to form a small-scale structure of the IGM.

  6. «Absolute Prohibition on Going to See the Infernal Spectacle of the White Sorcerer»: The Function of Narrative and Metaphor in the Historical Reconstitution of Cinematographic Spectacle in an African Village

    Directory of Open Access Journals (Sweden)

    Mahomed Bamba

    2014-10-01

    Full Text Available The article deals with the historical reconstruction of a case of cinematography’s cultural reception in an Islamic African village. My interpretative analysis of this process is based on a reading of a short story by Amadou Bâ Hampâté. From Bâ’s text, I raise a number of questions: how do the enunciative structures of a first-person account and the speeches of other characters and viewers mix with a historical description? What does the figure of the spectator of the first cinema reflect? Are the speech, opinions and public reactions in that African village about cinema different from or similar to those of other publics around the world at that time? What are the socio-cultural determinations and mediations that Bâ’s narrative allows us to glimpse between cinematic spectacle and religious «institution»? What is the role of metaphor in the cultural reception of cinematography? My hypothesis is that the narrative of Bâ can be read and interpreted as both a metaphor and a historical document.

  7. DeepLensing: The Use of Deep Machine Learning to Find Strong Gravitational Lenses in Astronomical Surveys

    Science.gov (United States)

    Nord, Brian

    2017-01-01

    Strong gravitational lenses have potential as very powerful probes of dark energy and cosmic structure. However, efficiently finding lenses poses a significant challenge—especially in the era of large-scale cosmological surveys. I will present a new application of deep machine learning algorithms to find strong lenses, as well as the strong lens discovery program of the Dark Energy Survey (DES).Strong lenses provide unique information about the evolution of distant galaxies, the nature of dark energy, and the shapes of dark matter haloes. Current and future surveys, like DES and the Large Synoptic Survey Telescope, present an opportunity to find many thousands of strong lenses, far more than have ever been discovered. By and large, searches have heretofore relied on the time-consuming effort of human scanners. Deep machine learning frameworks, like convolutional neural nets, have revolutionized the task of image recognition, and have a natural place in the processing of astronomical images, including the search for strong lenses.Over five observing seasons, which started in August 2013, DES will carry out a wide-field survey of 5000 square degrees of the Southern Galactic Cap. DES has identified nearly 200 strong lensing candidates in the first two seasons of data. We have performed spectroscopic follow-up on a subsample of these candidates at Gemini South, confirming over a dozen new strong lenses. I will present this DES discovery program, including searches and spectroscopic follow-up of galaxy-scale, cluster-scale and time-delay lensing systems.I will focus, however, on a discussion of the successful search for strong lenses using deep learning methods. In particular, we show that convolutional neural nets present a new set of tools for efficiently finding lenses, and accelerating advancements in strong lensing science.

  8. File list: DNS.Oth.05.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.05.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.05.AllAg.Lenses,_Intraocular.bed ...

  9. File list: DNS.Oth.50.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.50.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.50.AllAg.Lenses,_Intraocular.bed ...

  10. File list: DNS.Oth.20.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.20.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.20.AllAg.Lenses,_Intraocular.bed ...

  11. File list: DNS.Oth.10.AllAg.Lenses,_Intraocular [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Oth.10.AllAg.Lenses,_Intraocular mm9 DNase-seq Others Lenses, Intraocular http:...//dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/DNS.Oth.10.AllAg.Lenses,_Intraocular.bed ...

  12. Reconstructing the lensing mass in the Universe from photometric catalogue data

    NARCIS (Netherlands)

    Collett, Thomas E.; Marshall, Philip J.; Auger, Matthew W.; Hilbert, Stefan; Suyu, Sherry H.; Greene, Zachary; Treu, Tommaso; Fassnacht, Christopher D.; Koopmans, Leon V. E.; Bradac, Marusa; Blandford, Roger D.

    2013-01-01

    High precision cosmological distance measurements towards individual objects such as time delay gravitational lenses or Type Ia supernovae are affected by weak lensing perturbations by galaxies and groups along the line of sight. In time delay gravitational lenses, 'external convergence',

  13. Biodegradability of plastics.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P; Ugwu, Charles U; Aiba, Seiichi

    2009-08-26

    Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.). In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  14. Plastic value chains

    DEFF Research Database (Denmark)

    Baxter, John; Wahlstrom, Margareta; Zu Castell-Rüdenhausen, Malin

    2014-01-01

    Optimizing plastic value chains is regarded as an important measure in order to increase recycling of plastics in an efficient way. This can also lead to improved awareness of the hazardous substances contained in plastic waste, and how to avoid that these substances are recycled. As an example......, plastics from WEEE is chosen as a Nordic case study. The project aims to propose a number of improvements for this value chain together with representatives from Nordic stakeholders. Based on the experiences made, a guide for other plastic value chains shall be developed....

  15. Biodegradability of Plastics

    Directory of Open Access Journals (Sweden)

    Yutaka Tokiwa

    2009-08-01

    Full Text Available Plastic is a broad name given to different polymers with high molecular weight, which can be degraded by various processes. However, considering their abundance in the environment and their specificity in attacking plastics, biodegradation of plastics by microorganisms and enzymes seems to be the most effective process. When plastics are used as substrates for microorganisms, evaluation of their biodegradability should not only be based on their chemical structure, but also on their physical properties (melting point, glass transition temperature, crystallinity, storage modulus etc.. In this review, microbial and enzymatic biodegradation of plastics and some factors that affect their biodegradability are discussed.

  16. Journal of CHINA PLASTICS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Journal of CHINA PLASTICS was authorized and approved by The State Committee of Science and Technology of China and The Bureau of News Press of China, and published by The China Plastics Processing Industry Association,Beijing Technology and Business University and The Institute of Plastics Processing and Application of Light Industry, distributed worldwide. Since its birth in 1987, CHINA PLASTICS has become a leading magazine in plastics industry in China, a national Chinese core journal and journal of Chinese scientific and technological article statistics. It is covered by CA.

  17. Challenges in plastics recycling

    DEFF Research Database (Denmark)

    Pivnenko, Kostyantyn; Jakobsen, L. G.; Eriksen, Marie Kampmann

    2015-01-01

    Recycling of waste plastics still remains a challenging area in the waste management sector. The current and potential goals proposed on EU or regional levels are difficult to achieve, and even to partially fullfil them the improvements in collection and sorting should be considerable. A study...... was undertaken to investigate the factors affecting quality in plastics recycling. The preliminary results showed factors primarily influencing quality of plastics recycling to be polymer cross contamination, presence of additives, non-polymer impurities, and polymer degradation. Deprivation of plastics quality......, with respect to recycling, has been shown to happen throughout the plastics value chain, but steps where improvements may happen have been preliminary identified. Example of Cr in plastic samples analysed showed potential spreading and accumulation of chemicals ending up in the waste plastics. In order...

  18. Glassy metallic plastics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper reports a class of bulk metallic glass including Ce-, LaCe-, CaLi-, Yb-, and Sr-based metallic glasses, which are regarded as glassy metallic plastics because they combine some unique properties of both plastics and metallic alloys. These glassy metallic plastics have very low glass transition temperature (Tg~25oC to 150oC) and low Young’s modulus (~20 GPa to 35 GPa). Similar to glassy plastics, these metallic plastics show excellent plastic-like deformability on macro-, micro- and even nano-scale in their supercooled liquid range and can be processed, such as elongated, compressed, bent, and imprinted at low temperatures, in hot water for instance. Under ambient conditions, they display such metallic properties as high thermal and electric conductivities and excellent mechanical properties and other unique properties. The metallic plastics have potential applications and are also a model system for studying issues in glass physics.

  19. Compound lensing: Einstein Zig-Zags and high multiplicity lensed images

    CERN Document Server

    Collett, Thomas E

    2015-01-01

    Compound strong gravitational lensing is a rare phenomenon, but a handful of such lensed systems are likely to be discovered in forthcoming surveys. In this work, we use a double SIS lens model to analytically understand how the properties of the system impact image multiplicity for the final source. We find that up to six images of a background source can form, but only if the second lens is multiply imaged by the first and the Einstein radius of the second lens is comparable to, but does not exceed that of the first. We then build a model of compound lensing masses in the Universe, using SIE lenses, and assess how the optical depth for multiple imaging by a galaxy-galaxy compound lens varies with source redshift. For a source redshift of 4, we find optical depths of $6 \\times 10^{-6}$ for multiple imaging and $5 \\times 10^{-8}$ for multiplicity of 6 or greater. We find that extreme magnifications are possible, with magnifications of 100 or more for $6 \\times 10^{-9}$ of $z=10$ sources with 0.1 kpc radii. We...

  20. Roulettes: A weak lensing formalism for strong lensing - II. Derivation and analysis

    CERN Document Server

    Clarkson, Chris

    2016-01-01

    We present a new extension of the weak lensing formalism capable of describing strongly lensed images. This paper accompanies Paper I, where we provided a condensed overview of the approach and illustrated how it works. Here we give all the necessary details, together with some more explicit examples. We solve the non-linear geodesic deviation equation order-by-order, keeping the leading derivatives of the optical tidal matrix, giving rise to a series of maps from which a complete strongly lensed image is formed. The family of maps are decomposed by separating the trace and trace-free parts of each map. Each trace-free tensor represents an independent spin mode, which distort circles into a variety of roulettes in the screen-space. It is shown how summing this series expansion allows us to create large strongly lensed images in regions where convergence, shear and flexion are not sufficient. This paper is a detailed exposition of Paper I which presents the key elements of the subject matter in a wider context...

  1. Roulettes: a weak lensing formalism for strong lensing: II. Derivation and analysis

    Science.gov (United States)

    Clarkson, Chris

    2016-12-01

    We present a new extension of the weak lensing formalism capable of describing strongly lensed images. This paper accompanies Paper I (Clarkson C 2016 Class. Quantum Grav. 33 16LT01), where we provide a condensed overview of the approach and illustrated how it works. Here we give all the necessary details, together with some more explicit examples. We solve the nonlinear geodesic deviation equation order-by-order, keeping the leading derivatives of the optical tidal matrix, giving rise to a series of maps from which a complete strongly lensed image is formed. The family of maps are decomposed by separating the trace and trace-free parts of each map. Each trace-free tensor represents an independent spin mode, which distorts circles into a variety of roulettes in the screen-space. It is shown how summing this series expansion allows us to create large strongly lensed images in regions where convergence, shear and flexion are not sufficient. This paper is a detailed exposition of Paper I [1], which presents the key elements of the subject matter in a wider context.

  2. Prevalence and causes of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China.

    Science.gov (United States)

    He, Jiangnan; Lu, Lina; Zou, Haidong; He, Xiangui; Li, Qiangqiang; Wang, Weijie; Zhu, Jianfeng

    2014-12-22

    To assess the prevalence of visual impairment and rate of wearing spectacles in schools for children of migrant workers in Shanghai, China. Children from grade 1 to 5 in schools for children of migrant workers were randomly chosen for ocular examinations. All children were screened for uncorrected visual acuity and presenting visual acuity. After screening, the children whose uncorrected visual acuity was 20/40 or less received ocular motility evaluation, cycloplegic refraction/non-cycloplegic refraction, and external eye, anterior segment, media, and fundus examinations. A total of 9673 children were enumerated and 9512 (98.34%) participated in this study. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye were 13.33%, 11.26%, and 0.63%, respectively. The rate of wearing spectacles of the children with visual impairment in one or both eyes was 15.50%. Of these, 26.05% were wearing spectacles with inaccurate prescriptions. Refractive error was a major cause of visual impairment, accounting for 89.48% of all the visual impairment causes. Other causes of visual impairment included amblyopia accounting for 10.12%; congenital cataract, 0.1%; congenital nystagmus, 0.1%; ocular prosthesis, 0.1%; macular degeneration, 0.05%; and opaque cornea, 0.05%. This is the first study of the prevalence and causes of visual impairment in schools for children of migrant workers in Shanghai, China. The visual impairment rate in schools for children of migrant workers in suburbs of Shanghai in the best eye before vision correction was lower than those of urban children in mainstream schools in Guangzhou in 2012, and higher than students in rural of Beijing in 1998 and in suburb of Chongqing in 2007. The refractive error was the principal cause of the visual impairment of the children of migrant workers. The rate of wearing spectacles was low and the percentage of inaccurate prescriptions, among those who wore spectacles, was

  3. Lizard Wears Shades. A Spectacled Sphenomorphus (Squamata: Scincidae), from the Sacred Forests of Mawphlang, Meghalaya, North-east India.

    Science.gov (United States)

    Datta-Roy, Aniruddha; Das, Indraneil; Bauer, Aaron M; Tron, Ronald K Lyngdoh; Karanth, Praveen

    2013-01-01

    A new species of lygosomatine scincid lizard is described from the sacred forests of Mawphlang, in Meghalaya, northeastern India. Sphenomorphus apalpebratus sp. nov. possesses a spectacle or brille, an unusual feature within the Scincidae, and a first for the paraphyletic genus Sphenomorphus. The new species is compared with other members of the genus to which it is here assigned, as well as to members of the lygosomatine genera Lipinia and Scincella from mainland India, the Andaman and Nicobar Islands, and southeast Asia, to which it also bears resemblance. The new taxon is diagnosable in exhibiting the following combination of characters: small body size (SVL to 42.0 mm); moveable eyelids absent; auricular opening scaleless, situated in a shallow depression; dorsal scales show a line of demarcation along posterior edge of ventral pes; midbody scale rows 27-28; longitudinal scale rows between parietals and base of tail 62-64; lamellae under toe IV 8-9; supraoculars five; supralabials 5-6; infralabials 4-5; subcaudals 92; and dorsum golden brown, except at dorsal margin of lateral line, which is lighter, with four faintly spotted lines, two along each side of vertebral row of scales, that extend to tail base. The new species differs from its congeners in the lack of moveable eyelids, a character shared with several distantly related scincid genera.

  4. Spurious Shear in Weak Lensing with LSST

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.

    2012-09-19

    The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.

  5. The Future of Myopia Control Contact Lenses.

    Science.gov (United States)

    Gifford, Paul; Gifford, Kate Louise

    2016-04-01

    The growing incidence of pediatric myopia worldwide has generated strong scientific interest in understanding factors leading to myopia development and progression. Although contact lenses (CLs) are prescribed primarily for refractive correction, there is burgeoning use of particular modalities for slowing progression of myopia following reported success in the literature. Standard soft and rigid CLs have been shown to have minimal or no effect for myopia control. Overall, orthokeratology and soft multifocal CLs have shown the most consistent performance for myopia control with the least side effects. However, their acceptance in both clinical and academic spheres is influenced by data limitations, required off-label usage, and a lack of clear understanding of their mechanisms for myopia control. Myopia development and progression seem to be multifactorial, with a complex interaction between genetics and environment influencing myopigenesis. The optical characteristics of the individual also play a role through variations in relative peripheral refraction, binocular vision function, and inherent higher-order aberrations that have been linked to different refractive states. Contact lenses provide the most viable opportunity to beneficially modify these factors through their close alignment with the eye and consistent wearing time. Contact lenses also have potential to provide a pharmacological delivery device and a possible feedback mechanism for modification of a visual environmental risk. An examination of current patents on myopia control provides a window to the future development of an ideal myopia-controlling CL, which would incorporate the broadest treatment of all currently understood myopigenic factors. This ideal lens must also satisfy safety and comfort aspects, along with overcoming practical issues around U.S. Food and Drug Administration approval, product supply, and availability to target populations. Translating the broad field of myopia research

  6. The Strong Lensing Time Delay Challenge (2014)

    Science.gov (United States)

    Liao, Kai; Dobler, G.; Fassnacht, C. D.; Treu, T.; Marshall, P. J.; Rumbaugh, N.; Linder, E.; Hojjati, A.

    2014-01-01

    Time delays between multiple images in strong lensing systems are a powerful probe of cosmology. At the moment the application of this technique is limited by the number of lensed quasars with measured time delays. However, the number of such systems is expected to increase dramatically in the next few years. Hundred such systems are expected within this decade, while the Large Synoptic Survey Telescope (LSST) is expected to deliver of order 1000 time delays in the 2020 decade. In order to exploit this bounty of lenses we needed to make sure the time delay determination algorithms have sufficiently high precision and accuracy. As a first step to test current algorithms and identify potential areas for improvement we have started a "Time Delay Challenge" (TDC). An "evil" team has created realistic simulated light curves, to be analyzed blindly by "good" teams. The challenge is open to all interested parties. The initial challenge consists of two steps (TDC0 and TDC1). TDC0 consists of a small number of datasets to be used as a training template. The non-mandatory deadline is December 1 2013. The "good" teams that complete TDC0 will be given access to TDC1. TDC1 consists of thousands of lightcurves, a number sufficient to test precision and accuracy at the subpercent level, necessary for time-delay cosmography. The deadline for responding to TDC1 is July 1 2014. Submissions will be analyzed and compared in terms of predefined metrics to establish the goodness-of-fit, efficiency, precision and accuracy of current algorithms. This poster describes the challenge in detail and gives instructions for participation.

  7. Tevatron Electron Lenses: Design and Operation

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir; /Fermilab; Bishofberger, Kip; /Los Alamos; Kamerdzhiev, Vsevolod; /Fermilab; Kozub, Sergei; /Serpukhov, IHEP; Kufer, Matthew; Kuznetsov, Gennady; Martinez, Alexander; Olson, Marvin; Pfeffer, Howard; Saewert, Greg; Scarpine, Vic; /Fermilab; Seryi, Andrei; /SLAC; Solyak, Nikolai; /Fermilab; Sytnik, Veniamin; /Serpukhov, IHEP; Tiunov, Mikhail; /Novosibirsk, IYF; Tkachenko, Leonid; /Serpukhov, IHEP; Wildman, David; Wolff, Daniel; Zhang, Xiao-Long; /Fermilab

    2011-09-12

    Fermilab's Tevatron is currently the world's highest energy accelerator in which tightly focused beams of 980 GeV protons and antiprotons collide at two dedicated interaction points (IPs). Both beams share the same beam pipe and magnet aperture and, in order to avoid multiple detrimental head-on collisions, the beams are placed on separated orbits everywhere except the main IPs by using high-voltage (HV) electrostatic separators. The electromagnetic beam-beam interaction at the main IPs together with the long-range interactions between separated beams adversely affect the collider performance, reducing the luminosity integral per store (period of continuous collisions) by 10-30%. Tuning the collider operation for optimal performance becomes more and more cumbersome as the beam intensities and luminosity increase. The long-range effects which (besides being nonlinear) vary from bunch to bunch are particularly hard to mitigate. A comprehensive review of the beam-beam effects in the Tevatron Collider Run II can be found in Ref. [1]. The beam-beam effects have been the dominating sources of beam loss and lifetime limitations in the Tevatron proton-antiproton collider [1]. Electron lenses were originally proposed for compensation of electromagnetic long-range and head-on beam-beam interactions of proton and antiproton beams [2]. Results of successful employment of two electron lenses built and installed in the Tevatron are reported in [3,4,5]. In this paper we present design features of the Tevatron electron lenses (TELs), discuss the generation of electron beams, describe different modes of operation and outline the technical parameters of various subsystems.

  8. Focal properties of geodesic waveguide lenses

    Science.gov (United States)

    Verber, C. M.; Vahey, D. W.; Wood, V. E.

    1976-01-01

    The focal properties of uncorrected geodesic lenses in ion-exchanged glass waveguides are reported. A 13.8-mm-focal-length lens resolved beams with an angular separation of 27.6 mrad, while a 28-mm-focal-length lens resolved beams with an angular separation of only 3.3 mrad. Intensity profiles of the focal region of the former lens revealed a 40-micron spot size when the input aperture was 5 mm, and a spot size of 7.7 microns when the aperture was reduced to 1 mm. This value is close to the diffraction-limited spot size of 5.7 microns.

  9. LensTools: Weak Lensing computing tools

    Science.gov (United States)

    Petri, A.

    2016-02-01

    LensTools implements a wide range of routines frequently used in Weak Gravitational Lensing, including tools for image analysis, statistical processing and numerical theory predictions. The package offers many useful features, including complete flexibility and easy customization of input/output formats; efficient measurements of power spectrum, PDF, Minkowski functionals and peak counts of convergence maps; survey masks; artificial noise generation engines; easy to compute parameter statistical inferences; ray tracing simulations; and many others. It requires standard numpy and scipy, and depending on tools used, may require Astropy (ascl:1304.002), emcee (ascl:1303.002), matplotlib, and mpi4py.

  10. Construction progress of the RHIC electron lenses

    Energy Technology Data Exchange (ETDEWEB)

    Fischer W.; Altinbas, Z.; Anerella, M.; Beebe, E.; et al

    2012-05-20

    In polarized proton operation the RHIC performance is limited by the head-on beam-beam effect. To overcome this limitation two electron lenses are under construction. We give an overview of the construction progress. Guns, collectors and the warm electron beam transport solenoids with their power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of the gun, collector and some of the instrumentation. The infrastructure is being prepared for installation, and simulations continue to optimize the performance.

  11. Strong Lensing Cosmography in the Frontier Fields

    Science.gov (United States)

    Jullo, Eric; Acebron, Ana; Limousin, Marceau; Giocoli, Carlo; Despali, Giulia; Bonamigo, Mario; Bonamigo

    The wealth of strong lensing features observed in the Frontier Fields clusters offers insights on the nature of dark energy. The large number of multiple-images systems with redshifts allows to simultaneously estimate the lens model parameters and the cosmological parameters involved in the distances calculations. In particular for the ΛCDM model, it is possible to estimate the matter density Ω m and the dark energy equations parameters w X . In this talk, I will present recent analyses of systematic errors based on Frontier Fields observed and simulated data.

  12. Gas lensing in a heated spinning pipe

    CSIR Research Space (South Africa)

    Mafusire, C

    2006-07-01

    Full Text Available Spinning Pipe C MAFUSIRE1,2, A FORBES2, G SNEDDEN3, C MAHLASE3, MM MICHAELIS4 & M MATHUTHU1 1University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe 2CSIR National Laser Centre, PO Box 395, Pretoria 0001, South Africa 3CSIR Defence Peace Safety... this system. BEAM PROPAGATION THROUGH GAS LENSES The heated spinning pipe acts as a GRIN lens where the refractive index variation inside the pipe is given by The variable parameters of the gas lens in this work were the rotation...

  13. Diffractive lenses recorded in absorbent photopolymers.

    Science.gov (United States)

    Fernández, R; Gallego, S; Márquez, A; Francés, J; Navarro-Fuster, V; Pascual, I

    2016-01-25

    Photopolymers can be appealing materials for diffractive optical elements fabrication. In this paper, we present the recording of diffractive lenses in PVA/AA (Polyvinyl alcohol acrylamide) based photopolymers using a liquid crystal device as a master. In addition, we study the viability of using a diffusion model to simulate the lens formation in the material and to study the influence of the different parameters that govern the diffractive formation in photopolymers. Once we control the influence of each parameter, we can fit an optimum recording schedule to record each different diffractive optical element with the optimum focalization power.

  14. Magnified Weak Lensing Cross Correlation Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    This project carried out a weak lensing tomography (WLT) measurement around rich clusters of galaxies. This project used ground based photometric redshift data combined with HST archived cluster images that provide the WLT and cluster mass modeling. The technique has already produced interesting results (Guennou et al, 2010,Astronomy & Astrophysics Vol 523, page 21, and Clowe et al, 2011 to be submitted). Guennou et al have validated that the necessary accuracy can be achieved with photometric redshifts for our purposes. Clowe et al titled "The DAFT/FADA survey. II. Tomographic weak lensing signal from 10 high redshift clusters," have shown that for the **first time** via this purely geometrical technique, which does not assume a standard rod or candle, that a cosmological constant is **required** for flat cosmologies. The intent of this project is not to produce the best constraint on the value of the dark energy equation of state, w. Rather, this project is to carry out a sustained effort of weak lensing tomography that will naturally feed into the near term Dark Energy Survey (DES) and to provide invaluable mass calibration for that project. These results will greatly advance a key cosmological method which will be applied to the top-rated ground-based project in the Astro2020 decadal survey, LSST. Weak lensing tomography is one of the key science drivers behind LSST. CO-I Clowe is on the weak lensing LSST committee, and senior scientist on this project, at FNAL James Annis, plays a leading role in the DES. This project has built on successful proposals to obtain ground-based imaging for the cluster sample. By 1 Jan, it is anticipated the project will have accumulated complete 5-color photometry on 30 (or about 1/3) of the targeted cluster sample (public webpage for the survey is available at http://cencos.oamp.fr/DAFT/ and has a current summary of the observational status of various clusters). In all, the project has now been awarded the equivalent of over 60

  15. Modern Surgical Treatment of Congenital Subluxated Lenses

    Institute of Scientific and Technical Information of China (English)

    1992-01-01

    Traditional surgical management of subluxated lenses is usuallyassociated with a high incidence of operative and postoperative complicationand a poor visual outcome.We treated a series of 14 patients(26 eyes)whose visual acuity could not be improved with optical correction(phakic oraphakic)with modern microsurgery and automated suction-cutting devices.Preoperative visual acuity ranged from 0.05 to 0.3.Improvement in post-opera-tive visual acuity was documented in all operated eyes,ranging from 0.4 to 1....

  16. Construction progress of the RHIC electron lenses

    Energy Technology Data Exchange (ETDEWEB)

    Fischer W.; Altinbas, Z.; Anerella, M.; Beebe, E.; et al

    2012-05-20

    In polarized proton operation the RHIC performance is limited by the head-on beam-beam effect. To overcome this limitation two electron lenses are under construction. We give an overview of the construction progress. Guns, collectors and the warm electron beam transport solenoids with their power supplies have been constructed. The superconducting solenoids that guide the electron beam during the interaction with the proton beam are near completion. A test stand has been set up to verify the performance of the gun, collector and some of the instrumentation. The infrastructure is being prepared for installation, and simulations continue to optimize the performance.

  17. Magnified Weak Lensing Cross Correlation Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, Melville P., Clowe, Douglas I.

    2010-11-30

    This project carried out a weak lensing tomography (WLT) measurement around rich clusters of galaxies. This project used ground based photometric redshift data combined with HST archived cluster images that provide the WLT and cluster mass modeling. The technique has already produced interesting results (Guennou et al, 2010,Astronomy & Astrophysics Vol 523, page 21, and Clowe et al, 2011 to be submitted). Guennou et al have validated that the necessary accuracy can be achieved with photometric redshifts for our purposes. Clowe et al titled "The DAFT/FADA survey. II. Tomographic weak lensing signal from 10 high redshift clusters," have shown that for the **first time** via this purely geometrical technique, which does not assume a standard rod or candle, that a cosmological constant is **required** for flat cosmologies. The intent of this project is not to produce the best constraint on the value of the dark energy equation of state, w. Rather, this project is to carry out a sustained effort of weak lensing tomography that will naturally feed into the near term Dark Energy Survey (DES) and to provide invaluable mass calibration for that project. These results will greatly advance a key cosmological method which will be applied to the top-rated ground-based project in the Astro2020 decadal survey, LSST. Weak lensing tomography is one of the key science drivers behind LSST. CO-I Clowe is on the weak lensing LSST committee, and senior scientist on this project, at FNAL James Annis, plays a leading role in the DES. This project has built on successful proposals to obtain ground-based imaging for the cluster sample. By 1 Jan, it is anticipated the project will have accumulated complete 5-color photometry on 30 (or about 1/3) of the targeted cluster sample (public webpage for the survey is available at http://cencos.oamp.fr/DAFT/ and has a current summary of the observational status of various clusters). In all, the project has now been awarded the equivalent of over 60

  18. Ultimate resolution of indefinite metamaterial flat lenses

    CERN Document Server

    Bénédicto, Jessica; Pollès, Rémi; Moreau, Antoine

    2013-01-01

    We show that any metallo-dielectric multilayer with a hyperbolic dispersion relation can actually be characterized by a complex effective index. This refractive index, extracted from the complex Bloch band diagram, can be directly linked to the super-resolution of a flat lens made of this so- called indefinite metamaterials. This allows for a systematic optimization of the lens design, leading to structures that are outperforming state-of-art flat lenses. We show that, even when fully taking absorption into account, our design provides super-resolved images for visible light up to a distance of one wavelength from the lens edge.

  19. Operations of the Tevatron Electron Lenses

    CERN Document Server

    Zhang, X L; Valishev, A; Stancari, G; Kuznetsov, G; Saewert, G; Kamerdzhiev, V

    2012-01-01

    The two Tevatron Electron Lenses (TEL1 and TEL2) are installed in Tevatron in 2001 and 2006 respectively. TEL1 is operated as the vital parts of the Tevatron for abort gap beam clearing, while TEL2 is functioning as the backup as well as the test device for beam-beam compensation, space charge compensator and soft beam collimator. Both of them are working exceptionally reliable after a few initial kinks being worked out. Their operations in Tevatron are summarized in this report.

  20. Microstructured gradient-index lenses for THz photoconductive antennas

    DEFF Research Database (Denmark)

    Brincker, Mads; Karlsen, Peter; Skovsen, Esben

    2016-01-01

    constant can be designed to function like a gradient index (GRIN) lens. The proposed GRIN substrate lenses have sub-mm dimension, which is smaller than the dimensions of a typical hyper-hemispherical substrate lens (HSL), and could enable fabrication of arrays of closely packed PCA’s with individual lenses...

  1. Cosmological constraints from Subaru weak lensing cluster counts

    CERN Document Server

    Hamana, Takashi; Koike, Michitaro; Miller, Lance

    2015-01-01

    We present results of weak lensing cluster counts obtained from 11 sq.deg SuprimeCam data. Although the area is much smaller than previous work dealing with weak lensing peak statistics, the number density of galaxies usable for weak lensing analysis is about twice as large as those. The higher galaxy number density reduces the noise in the weak lensing mass maps, and thus increases the signal-to-noise ratio of peaks of the lensing signal due to massive clusters. This enables us to construct a weak lensing selected cluster sample by adopting a high threshold S/N, such that the contamination rate due to false signals is small. We find 6 peaks with S/N>5. For all the peaks, previously identified clusters of galaxies are matched within a separation of 1 arcmin, demonstrating good correspondence between the peaks and clusters of galaxies. We evaluate the statistical error using mock weak lensing data, and find Npeak=6+/-3.1 in an effective area of 9.0 sq.deg. We compare the measured weak lensing cluster counts wi...

  2. From Spheric to Aspheric Solid Polymer Lenses: A Review

    Directory of Open Access Journals (Sweden)

    Kuo-Yung Hung

    2011-01-01

    Full Text Available This paper presents a new approach in the use of MEMS technology to fabricate micro-optofluidic polymer solid lenses in order to achieve the desired profile, focal length, numerical aperture, and spot size. The resulting polymer solid lenses can be applied in optical data storage systems, imaging systems, and automated optical inspection systems. In order to meet the various needs of different applications, polymer solid lenses may have a spherical or aspherical shape. The method of fabricating polymer solid lenses is different from methods used to fabricate tunable lenses with variable focal length or needing an external control system to change the lens geometry. The current trend in polymer solid lenses is toward the fabrication of microlenses with a high numerical aperture, small clear aperture (<2 mm, and high transmittance. In this paper we focus on the use of thermal energy and electrostatic force in shaping the lens profile, including both spherical and aspherical lenses. In addition, the paper discusses how to fabricate a lens with a high numerical aperture of 0.6 using MEMS and also compares the optical characteristics of polymer lens materials, including SU-8, Norland Optical Adhesive (NOA, and cyclic olefin copolymer (COC. Finally, new concepts and applications related to micro-optofluidic lenses and polymer materials are also discussed.

  3. Extended drug delivery by contact lenses for glaucoma therapy.

    Science.gov (United States)

    Peng, Cheng-Chun; Burke, Michael T; Carbia, Blanca E; Plummer, Caryn; Chauhan, Anuj

    2012-08-20

    We combine laboratory-based timolol release studies and in vivo pharmacodynamics studies in beagle dogs to evaluate the efficacy of glaucoma therapy through extended wear contact lenses. Commercial contact lenses cannot provide extended delivery of ophthalmic drugs and so the studies here focused on increasing the release duration of timolol from ACUVUE TruEye contact lenses by incorporating vitamin E diffusion barriers. The efficacy of timolol delivered via extended wear contact lenses was then compared to eye drops in beagle dogs that suffer from spontaneous glaucoma. The lenses were either replaced every 24h or continuously worn for 4 days, and the pharmacodynamics effect of changes in the intraocular pressure (IOP) of timolol from the ACUVUE TruEye contact lenses can be significantly increased by incorporation of vitamin E. The in vivo studies showed that IOP reduction from baseline by pure contact lens on daily basis was comparable with that by eye drops but with only 20% of drug dose, which suggested higher drug bioavailability for contact lenses. In addition, by inclusion of vitamin E into the lenses, the IOP was reduced significantly during the 4-day treatment with continuous wear of lens.

  4. New observable for gravitational lensing effects during transits

    CERN Document Server

    Kasuya, Shinta; Mishima, Risa

    2010-01-01

    We investigate gravitational lensing effects of an extrasolar planet transiting its host star. We focus on the `rising spikes' of the light curve just before and after the transit, which is a peculiar feature of the gravitational lensing, and find that it could be a novel observable for determining physical parameters. Detectability of such an effect is also discussed.

  5. Self-lensing of a Singular Isothermal Sphere

    OpenAIRE

    Wang, Yun

    1999-01-01

    Many astrophysical systems can be approximated as isothermal spheres. In an isothermal sphere, the ``foreground'' objects can act as lenses on ``background'' objects in the same distribution. We study gravitational lensing by a singular isothermal sphere analytically. Our results may have interesting applications.

  6. Increased Expression of Interleukin-18 in Lenses of Ovariectomized Rats.

    Science.gov (United States)

    Nagai, Noriaki; Ogata, Fumihiko; Kawasaki, Naohito; Ito, Yoshimasa

    2016-01-01

    Previous studies showed an increased prevalence of cataracts in postmenopausal women. In this study, we investigated changes in the levels of calcium ion (Ca(2+)) and interleukin (IL)-18, which are factors in cataract development, in the lenses of ovariectomized (OVX) rats, a model of postmenopausal woman. Although the Ca(2+) content in the blood of OVX rats increased 1 month after ovariectomy and subsequently decreased, the Ca(2+) content in the lenses was unchanged in OVX rats 1-3 months after ovariectomy. The Ca(2+)-ATPase activity in the lenses of OVX rats peaked 1 month after ovariectomy, and the behavior of Ca(2+)-ATPase activity in lenses of OVX rats was similar to that of the Ca(2+) concentration in the blood. It is possible that hypercalcemia increases the Ca(2+) inflow into the lens; however, the enhanced Ca(2+)-ATPase activity prevents the Ca(2+) level from rising. On the other hand, we found that the levels of both IL-18 and interferon (IFN)-γ in the lenses of OVX rats were significantly increased as compared with the lenses of sham (control) rats during the period 1-3 months after surgery. These results suggest that the expression of IFN-γ via IL-18 in the lenses of OVX rats is induced by ovariectomy, and that excessive IL-18 and IFN-γ production in the lenses may be related to cataract development in postmenopausal women. These findings support those of previous studies that assessed lens opacification in postmenopausal women.

  7. Shallow rainwater lenses in deltaic areas with saline seepage

    NARCIS (Netherlands)

    Louw, de P.G.B.; Eeman, S.; Siemon, B.; `Voortman, B.R.; Gunnink, J.; Baaren, E.S.; Oude Essink, G.H.P.

    2011-01-01

    In deltaic areas with saline seepage, freshwater availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence and

  8. Shallow rainwater lenses in deltaic areas with saline seepage

    NARCIS (Netherlands)

    De Louw, Perry G.B.; Eeman, Sara; Siemon, Bernhard; Voortman, Bernard R.; Gunnink, Jan; Van Baaren, Esther S.; Oude Essink, Gualbert

    2011-01-01

    In deltaic areas with saline seepage, fresh water availability is often limited to shallow rainwater lenses lying on top of saline groundwater. Here we describe the characteristics and spatial variability of such lenses in areas with saline seepage and the mechanisms that control their occurrence an

  9. Combined reconstruction of weak and strong lensing data with WSLAP

    CERN Document Server

    Diego-Rodriguez, J M; Protopapas, P; Sandvik, H B

    2005-01-01

    We describe a method to estimate the mass distribution of a gravitational lens and the position of the sources from combined strong and weak lensing data. The algorithm combines weak and strong lensing data in a unified way producing a solution which is valid in both the weak and strong lensing regimes. We study how the result depends on the relative weighting of the weak and strong lensing data and on choice of basis to represent the mass distribution. We find that combining weak and strong lensing information has two major advantages: it eliminates the need for priors and/or regularization schemes for the intrinsic size of the background galaxies (this assumption was needed in previous strong lensing algorithms) and it corrects for biases in the recovered mass in the outer regions where the strong lensing data is less sensitive. The code is implemented into a software package called WSLAP (Weak & Strong Lensing Analysis Package) which is publicly available at http://darwin.cfa.harvard.edu/SLAP/

  10. Gravitational Lensing of Gravitational Waves from Merging Neutron Star Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.; Stebbins, A.; Turner, E.L. [NASA/Fermilab Astrophysics Center, FNAL, Batavia, Illinois 60510 (United States)]|[Princeton University Observatory, Peyton Hall, Princeton, New Jersey 08544 (United States)

    1996-09-01

    We discuss the gravitational lensing of gravitational waves from merging neutron star binaries, in the context of advanced LIGO type gravitational wave detectors. An advanced LIGO should see unlensed inspiral events with a redshift distribution with cutoff at a redshift {ital z}{sub max}{lt}1 for {ital h}{le}0.8. Any inspiral events detected at {ital z}{approx_gt}{ital z}{sub max} should be lensed. We compute the expected total number of events which are present due to gravitational lensing and their redshift distribution for an advanced LIGO in a flat universe. If the matter fraction in compact lenses is close to 10{percent}, an advanced LIGO should see a few strongly lensed events per year with {rho}{approx_gt}5. {copyright} {ital 1996 The American Physical Society.}

  11. Gravitational lensing of gravitational waves from merging neutron star binaries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yun; Stebbins, Albert; Turner, Edwin L.

    1996-05-01

    We discuss the gravitational lensing of gravitational waves from merging neutron star binaries, in the context of advanced LIGO type gravitational wave detectors. We consider properties of the expected observational data with cut on the signal-to-noise ratio \\rho, i.e., \\rho>\\rho_0. An advanced LIGO should see unlensed inspiral events with a redshift distribution with cut-off at a redshift z_{\\rm max} < 1 for h \\leq 0.8. Any inspiral events detected at z>z_{\\rm max} should be lensed. We compute the expected total number of events which are present due to gravitational lensing and their redshift distribution for an advanced LIGO in a flat Universe. If the matter fraction in compact lenses is close to 10\\%, an advanced LIGO should see a few strongly lensed events per year with \\rho >5.

  12. Probabilistic Cosmological Mass Mapping from Weak Lensing Shear

    CERN Document Server

    Schneider, Michael D; Dawson, William A; Marshall, Philip J; Meyers, Joshua; Bard, Deborah J

    2016-01-01

    We infer gravitational lensing shear and convergence fields from galaxy ellipticity catalogs under a spatial process prior for the lensing potential. We demonstrate the performance of our algorithm with simulated Gaussian-distributed cosmological lensing shear maps and a reconstruction of the mass distribution of the merging galaxy cluster Abell 781 using galaxy ellipticities measured with the Deep Lens Survey. Given interim posterior samples of lensing shear or convergence fields on the sky, we describe an algorithm to infer cosmological parameters via lens field marginalization. In the most general formulation of our algorithm we make no assumptions about weak shear or Gaussian distributed shape noise or shears. Because we require solutions and matrix determinants of a linear system of dimension that scales with the number of galaxies, we expect our algorithm to require parallel high-performance computing resources for application to ongoing wide field lensing surveys.

  13. Weak lensing at the limit of the sky background noise

    CERN Document Server

    Mellier, Y

    1996-01-01

    Recent weak lensing observations have pushed the use of 4 meter-class telescopes to the limits of their capabilities with exposure times exceeding several hours. The leading idea is that the surface density of faint galaxies up to very faint magnitude ($B > 28-30$) raises continuously thus potentially offering a dense template of distant sources whose intensity contrast is at the sky noise level. In complement to the Peter Schneider's presentation on dark matter search from weak lensing (this conference), we review some of these recent advances in weak lensing analysis based on this extreme faint population of galaxies in order to explore: the dark matter distribution on large scales, the redshift ditribution of lensed sources at very large distance, and eventually the values of cosmological parameters. For each observational topic we will briefly discuss these new methods as compare to more classical lensing studies as well as the possible VLT scientific impact in the domain.

  14. Lensing clusters of galaxies in the SDSS-Ⅲ

    Institute of Scientific and Technical Information of China (English)

    Zhong-Lue Wen; Jin-Lin Han; Yun-Ying Jiang

    2011-01-01

    We identify new strong lensing clusters of galaxies from the Sloan Digital Sky Survey Ⅲ (SDSS DR8) by visually inspecting color images of a large sample of clusters of galaxies.We find 68 new clusters showing giant arcs in addition to 30 known lensing systems.Among 68 cases,13 clusters are "almost certain" lensing systems with tangential giant arcs,22 clusters are "probable" and 31 clusters are "possible" lensing systems.We also find two exotic systems with blue rings.The giant arcs have angular separations of 2.0" - 25.7" from the bright central galaxies.We note that the rich clusters are more likely to be lensing systems and the separations between the arcs and the central galaxies increase with cluster richness.

  15. Separating intrinsic alignment and galaxy-galaxy lensing

    CERN Document Server

    Blazek, Jonathan; Seljak, Uros; Nakajima, Reiko

    2012-01-01

    The coherent physical alignment of galaxies is an important systematic for gravitational lensing studies as well as a probe of the physical mechanisms involved in galaxy formation and evolution. We develop a formalism for treating this intrinsic alignment (IA) in the context of galaxy-galaxy lensing, and present an improved method for measuring IA contamination, which can arise when sources physically associated with the lens are placed behind the lens due to photometric redshift scatter. We apply the technique to recent Sloan Digital Sky Survey (SDSS) measurements of Luminous Red Galaxy lenses and sources with photometric redshifts selected from the SDSS imaging data. Compared to previous measurements, this method has the advantage of being fully self-consistent in its treatment of the IA and lensing signals, solving for the two simultaneously. We find an IA signal consistent with zero, placing tight constraints on both the magnitude of the IA effect and its potential contamination to the lensing signal. Whi...

  16. Plasma surface modification of rigid contact lenses decreases bacterial adhesion.

    Science.gov (United States)

    Wang, Yingming; Qian, Xuefeng; Zhang, Xiaofeng; Xia, Wei; Zhong, Lei; Sun, Zhengtai; Xia, Jing

    2013-11-01

    Contact lens safety is an important topic in clinical studies. Corneal infections usually occur because of the use of bacteria-carrying contact lenses. The current study investigated the impact of plasma surface modification on bacterial adherence to rigid contact lenses made of fluorosilicone acrylate materials. Boston XO and XO2 contact lenses were modified using plasma technology (XO-P and XO2-P groups). Untreated lenses were used as controls. Plasma-treated and control lenses were incubated in solutions containing Staphylococcus aureus or Pseudomonas aeruginosa. MTT colorimetry, colony-forming unit counting method, and scanning electron microscopy were used to measure bacterial adhesion. MTT colorimetry measurements showed that the optical density (OD) values of XO-P and XO2-P were significantly lower than those of XO and XO2, respectively, after incubation with S. aureus (P plasma technology in contact lens surface modification.

  17. DYNAMIC SPECTRAL MAPPING OF INTERSTELLAR PLASMA LENSES

    Energy Technology Data Exchange (ETDEWEB)

    Tuntsov, Artem V.; Walker, Mark A. [Manly Astrophysics, 3/22 Cliff Street, Manly 2095 (Australia); Koopmans, Leon V. E. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, NL-9700 AV Groningen (Netherlands); Bannister, Keith W.; Stevens, Jamie; Johnston, Simon [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW 1710 (Australia); Reynolds, Cormac; Bignall, Hayley E., E-mail: Artem.Tuntsov@manlyastrophysics.org, E-mail: Mark.Walker@manlyastrophysics.org, E-mail: koopmans@astro.rug.nl [International Centre for Radio Astronomy Research—Curtin University, Perth (Australia)

    2016-02-01

    Compact radio sources sometimes exhibit intervals of large, rapid changes in their flux density, due to lensing by interstellar plasma crossing the line of sight. A novel survey program has made it possible to discover these “Extreme Scattering Events” (ESEs) in real time, resulting in a high-quality dynamic spectrum of an ESE observed in PKS 1939–315. Here we present a method for determining the column-density profile of a plasma lens, given only the dynamic radio spectrum of the lensed source, under the assumption that the lens is either axisymmetric or totally anisotropic. Our technique relies on the known, strong frequency dependence of the plasma refractive index in order to determine how points in the dynamic spectrum map to positions on the lens. We apply our method to high-frequency (4.2–10.8 GHz) data from the Australia Telescope Compact Array of the PKS 1939–315 ESE. The derived electron column-density profiles are very similar for the two geometries we consider, and both yield a good visual match to the data. However, the fit residuals are substantially above the noise level, and deficiencies are evident when we compare the predictions of our model to lower-frequency (1.6–3.1 GHz) data on the same ESE, thus motivating future development of more sophisticated inversion techniques.

  18. Continuous image distortion by astrophysical thick lenses

    CERN Document Server

    Kling, Thomas P

    2011-01-01

    Image distortion due to weak gravitational lensing is examined using a non-perturbative method of integrating the geodesic deviation and optical scalar equations along the null geodesics connecting the observer to a distant source. The method we develop continuously changes the shape of the pencil of rays from the source to the observer with no reference to lens planes in astrophysically relevant scenarios. We compare the projected area and the ratio of semi-major to semi-minor axes of the observed elliptical image shape for circular sources from the continuous, thick-lens method with the commonly assumed thin-lens approximation. We find that for truncated singular isothermal sphere and NFW models of realistic galaxy clusters, the commonly used thin-lens approximation is accurate to better than 1 part in 10^4 in predicting the image area and axes ratios. For asymmetric thick lenses consisting of two massive clusters separated along the line of sight in redshift up to \\Delta z = 0.2, we find that modeling the ...

  19. Dynamic spectral mapping of interstellar plasma lenses

    CERN Document Server

    Tuntsov, Artem V; Koopmans, Leon V E; Bannister, Keith W; Stevens, Jamie; Johnston, Simon; Reynolds, Cormac; Bignall, Hayley E

    2015-01-01

    Compact radio sources sometimes exhibit intervals of large, rapid changes in their flux-density, due to lensing by interstellar plasma crossing the line-of-sight. A novel survey program has made it possible to discover these "Extreme Scattering Events" (ESEs) in real time, resulting in a high-quality dynamic spectrum of an ESE observed in PKS 1939-315. Here we present a method for determining the column-density profile of a plasma lens, given only the dynamic radio spectrum of the lensed source, under the assumption that the lens is either axisymmetric or totally anisotropic. Our technique relies on the known, strong frequency dependence of the plasma refractive index in order to determine how points in the dynamic spectrum map to positions on the lens. We apply our method to high-frequency (4.2-10.8 GHz) data from the Australia Telescope Compact Array of the PKS 1939-315 ESE. The derived electron column-density profiles are very similar for the two geometries we consider, and both yield a good visual match t...

  20. Baryons, Neutrinos, Feedback and Weak Gravitational Lensing

    CERN Document Server

    Harnois-Déraps, Joachim; Viola, Massimo; Heymans, Catherine

    2014-01-01

    (Abridged) The effect of baryonic feedback on the dark matter mass distribution is generally considered to be a nuisance to weak gravitational lensing. Measurements of cosmological parameters are affected as feedback alters the cosmic shear signal on angular scales smaller than a few arcminutes. Recent progress on the numerical modelling of baryon physics has shown that this effect could be so large that, rather than being a nuisance, the effect can be constrained with current weak lensing surveys, hence providing an alternative astrophysical insight on one of the most challenging questions of galaxy formation. In order to perform our analysis, we construct an analytic fitting formula that describes the effect of the baryons on the mass power spectrum. This fitting formula is based on three scenarios of the OWL hydrodynamical simulations. It is specifically calibrated for $z<1.5$, where it models the simulations to an accuracy that is better than $2\\%$ for scales $k<10 h\\mbox{Mpc}^{-1}$ and better than ...

  1. Gravitational Lensing of Pregalactic 21 cm Radiation

    CERN Document Server

    Metcalf, R Benton

    2008-01-01

    Low-frequency radio observations of neutral hydrogen during and before the epoch of cosmic reionization will provide hundreds of quasi-independent source planes, each of precisely known redshift, if a resolution of ~ 1 arcminutes or better can be attained. These planes can be used to reconstruct the projected mass distribution of foreground material. A wide-area survey of 21 cm lensing would provide very sensitive constraints on cosmological parameters, in particular on dark energy. These are up to 20 times tighter than the constraints obtainable from comparably sized, very deep surveys of galaxy lensing although the best constraints come from combining data of the two types. Any radio telescope capable of mapping the 21cm brightness temperature with good frequency resolution (~ 0.05 MHz) over a band of width ~> 10 MHz should be able to make mass maps of high quality. If the reionization epoch is at z ~ 9 very large amounts of cosmological information will be accessible. The planned Square Kilometer Array (SK...

  2. Compound Refractive Lenses for Thermal Neutron Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gary, Charles K.

    2013-11-12

    This project designed and built compound refractive lenses (CRLs) that are able to focus, collimate and image using thermal neutrons. Neutrons are difficult to manipulate compared to visible light or even x rays; however, CRLs can provide a powerful tool for focusing, collimating and imaging neutrons. Previous neutron CRLs were limited to long focal lengths, small fields of view and poor resolution due to the materials available and manufacturing techniques. By demonstrating a fabrication method that can produce accurate, small features, we have already dramatically improved the focal length of thermal neutron CRLs, and the manufacture of Fresnel lens CRLs that greatly increases the collection area, and thus efficiency, of neutron CRLs. Unlike a single lens, a compound lens is a row of N lenslets that combine to produce an N-fold increase in the refraction of neutrons. While CRLs can be made from a variety of materials, we have chosen to mold Teflon lenses. Teflon has excellent neutron refraction, yet can be molded into nearly arbitrary shapes. We designed, fabricated and tested Teflon CRLs for neutrons. We demonstrated imaging at wavelengths as short as 1.26 ? with large fields of view and achieved resolution finer than 250 μm which is better than has been previously shown. We have also determined designs for Fresnel CRLs that will greatly improve performance.

  3. The theory of stochastic cosmological lensing

    CERN Document Server

    Fleury, Pierre; Uzan, Jean-Philippe

    2015-01-01

    On the scale of the light beams subtended by small sources, e.g. supernovae, matter cannot be accurately described as a fluid, which questions the applicability of standard cosmic lensing to those cases. In this article, we propose a new formalism to deal with small-scale lensing as a diffusion process: the Sachs and Jacobi equations governing the propagation of narrow light beams are treated as Langevin equations. We derive the associated Fokker-Planck-Kolmogorov equations, and use them to deduce general analytical results on the mean and dispersion of the angular distance. This formalism is applied to random Einstein-Straus Swiss-cheese models, allowing us to: (1) show an explicit example of the involved calculations; (2) check the validity of the method against both ray-tracing simulations and direct numerical integrations of the Langevin equation. As a byproduct, we obtain a post-Kantowski-Dyer-Roeder approximation, accounting for the effect of tidal distortions on the angular distance, in excellent agree...

  4. Calibrating Cluster Number Counts with CMB lensing

    CERN Document Server

    Louis, Thibaut

    2016-01-01

    CMB Stage-4 experiments will reduce the uncertainties on the gravitational lensing potential by an order of magnitude compared to current measurements, and will also produce a Sunyaev-Zel'dovich (SZ) cluster catalog containing $\\sim10^{5}$ objects, two orders of magnitudes higher than what is currently available. In this paper we propose to combine these two observables and show that it is possible to calibrate the masses of the full Stage-4 cluster catalog internally owing to the high signal to noise measurement of the CMB lensing convergence field. We find that a CMB Stage-4 experiment will constrain the hydrostatic bias parameter to sub-percent accuracy. We also show constraints on a non parametric $Y-M$ relationship which could be used to study its evolution with mass and redshift. Finally we present a joint likelihood for thermal SZ (tSZ) flux and mass measurements, and show that it could lead to a $\\sim5\\sigma$ detection of the lower limit on the sum of the neutrino masses in the normal hierarchy ($\\sum...

  5. Faint Submillimeter Galaxies Behind Lensing Clusters

    Science.gov (United States)

    Hsu, Li-Yen; Lauchlan Cowie, Lennox; Barger, Amy J.; Desai, Vandana; Murphy, Eric J.

    2017-01-01

    Faint submillimeter galaxies are the major contributors to the submillimeter extragalactic background light and hence the dominant star-forming population in the dusty universe. Determining how much these galaxies overlap the optically selected samples is critical to fully account for the cosmic star formation history. Observations of massive cluster fields are the best way to explore this faint submillimeter population, thanks to gravitational lensing effects. We have been undertaking a lensing cluster survey with the SCUBA-2 camera on the James Clerk Maxwell Telescope to map nine galaxy clusters, including the northern five clusters in the HST Frontier Fields program. We have also been using the Submillimeter Array and the Very Large Array to determine the accurate positions of our detected sources. Our observations have discovered high-redshift dusty galaxies with far-infrared luminosities similar to that of the Milky Way or luminous infrared galaxies. Some of these galaxies are still undetected in deep optical and near-infrared images. These results suggest that a substantial amount of star formation in even the faint submillimeter population may be hidden from rest-frame optical surveys.

  6. GLAMER - II. Multiple-plane gravitational lensing

    Science.gov (United States)

    Petkova, Margarita; Metcalf, R. Benton; Giocoli, Carlo

    2014-12-01

    We present an extension to multiple planes of the gravitational lensing code GLAMER. The method entails projecting the mass in the observed light-cone on to a discrete number of lens planes and inverse ray-shooting from the image to the source plane. The mass on each plane can be represented as haloes, simulation particles, a projected mass map extracted form a numerical simulation or any combination of these. The image finding is done in a source-oriented fashion, where only regions of interest are iteratively refined on an initially coarse image plane grid. The calculations are performed in parallel on shared memory machines. The code is able to handle different types of analytic haloes (NFW, NSIE, power law, etc.), haloes extracted from numerical simulations and clusters constructed from semi-analytic models (MOKA). Likewise, there are several different options for modelling the source(s) which can be distributed throughout the light-cone. The distribution of matter in the light-cone can be either taken from a pre-existing N-body numerical simulations, from halo catalogues, or are generated from an analytic mass function. We present several tests of the code and demonstrate some of its applications such as generating mock images of galaxy and galaxy cluster lenses.

  7. Simulations of Strong Gravitational Lensing with Substructure

    CERN Document Server

    Amara, A; Cox, T J; Ostriker, J P; Amara, Adam; Cox, Thomas J.; Ostriker, Jeremiah P.

    2004-01-01

    Galactic sized gravitational lenses are simulated by combining a cosmological N-body simulation and models for the baryonic component of the galaxy. The lens caustics, critical curves, image locations and magnification ratios are calculated by ray-shooting on an adaptive grid. It is found that the simulations do not cause the observed number of violations of the cusp caustic magnification relation. A part of this may be due to an insufficient amount of substructure but even for unsmoothed simulations (with maximal substructure) the factor of three increase in the number of violations still did not match the data. This suggests that other factors play an important role. These may include lensing by structure outside the halo, selection bias and the possibility that a randomly selected galaxy halo may be more irregular, for example due to recent mergers, than the isolated halo used in this study. It is also shown that, with the computed level of substructure, the image magnifications of the Einstein cross type ...

  8. Halo mass - concentration relation from weak lensing

    CERN Document Server

    Mandelbaum, Rachel; Hirata, Christopher M

    2008-01-01

    We perform a statistical weak lensing analysis of dark matter profiles around tracers of halo mass from galactic- to cluster-size halos. In this analysis we use 170,640 isolated ~L* galaxies split into ellipticals and spirals, 38,236 groups traced by isolated spectroscopic Luminous Red Galaxies (LRGs) and 13,823 MaxBCG clusters from the Sloan Digital Sky Survey (SDSS) covering a wide range of richness. Together these three samples allow a determination of the density profiles of dark matter halos over three orders of magnitude in mass, from 10^{12} M_{sun} to 10^{15} M_{sun}. The resulting lensing signal is consistent with an NFW or Einasto profile on scales outside the central region. We find that the NFW concentration parameter c_{200b} decreases with halo mass, from around 10 for galactic halos to 4 for cluster halos. Assuming its dependence on halo mass in the form of c_{200b} = c_0 [M/(10^{14}M_{sun}/h)]^{\\beta}, we find c_0=4.6 +/- 0.7 (at z=0.22) and \\beta=0.13 +/- 0.07, with very similar results for t...

  9. Shear calibration biases in weak lensing surveys

    CERN Document Server

    Hirata, C M; Hirata, Christopher M.; Seljak, Uros

    2003-01-01

    We investigate biases induced by the conversion between the observed image shape to shear distortion in current weak lensing analysis methods. Such overall calibration biases cannot be detected by the standard tests such as E/B decomposition or calibration with stars. We find that the non-Gaussianity of point spread function has a significant effect and can lead to up to 15 per cent error on the linear amplitude of fluctuations sigma_8 depending on the method of analysis. This could explain some of the discrepancies seen in recent amplitude determinations from weak lensing. Using an elliptical Laguerre expansion method we develop a re-Gaussianization method which reduces the error to calibration error of order 1 per cent even for poorly resolved galaxies. We also discuss a new type of shear selection bias which results in up to roughly 8 percent underestimation of the signal. It is expected to scale with redshift, inducing errors in the growth factor extraction if not properly corrected for. Understanding and...

  10. Weak Lensing Galaxy Cluster Field Reconstruction

    CERN Document Server

    Jullo, Eric; Jauzac, Mathilde; Kneib, Jean-Paul

    2013-01-01

    In this paper, we compare three methods to reconstruct galaxy cluster density fields with weak lensing data. The first method called FLens integrates an inpainting concept to invert the shear field with possible gaps, and a multi-scale entropy denoising procedure to remove the noise contained in the final reconstruction, that arises mostly from the random intrinsic shape of the galaxies. The second and third methods are based on a model of the density field made of a multi-scale grid of radial basis functions. In one case, the model parameters are computed with a linear inversion involving a singular value decomposition. In the other case, the model parameters are estimated using a Bayesian MCMC optimization implemented in the lensing software Lenstool. Methods are compared on simulated data with varying galaxy density fields. We pay particular attention to the errors estimated with resampling. We find the multi-scale grid model optimized with MCMC to provide the best results, but at high computational cost, ...

  11. Engineering acoustic lenses with help from evolution

    Science.gov (United States)

    Ha˚Kansson, Andreas; Sánchez-Dehesa, José; Sánchis, Lorenzo

    2004-05-01

    Optimization engineering through evolutionary algorithms have proven to be very efficient, especially in hard problems containing a large set of optimization parameters. Like evolution this family of algorithms is able to tackle enormous complex problems with fairly simple means. Here, a simple genetic algorithm [J. H. Holland, Adaptation in Natural and Artificial Systems (Univ. of Michigan, Ann Arbor, 1975)] is used in conjunction with the multiple scattering theory [L. Sánchis et al., Phys. Rev. B 67, 035422 (2003)] to fabricate a new generation of acoustic devices based on a discrete number of cylindrical scatterers. In particular, acoustic lenses [F. Cervera et al., Phys. Rev. Lett. 88, 023902 (2002)] with flat surfaces have been designed to focus the sound in a fixed focal point for one or multiple frequencies. Each scatterer is carefully placed using the optimization method within the preset boundary conditions, to maximize the pressure contribution in the chosen focal spot. With this method acoustic lenses with very low f-numbers of the order 0.3 and with amplifications over 12 dB have been estimated using a reduced number of scatterers (~60). Preliminary results obtained from the experimental realization of the designed devices confirm our predictions.

  12. A portable modeler of lensed quasars

    CERN Document Server

    Saha, P; Saha, Prasenjit; Williams, Liliya L.R.

    2004-01-01

    We introduce and implement two novel ideas for modeling lensed quasars. The first idea is to require different lenses to agree about H_0. This means that some models for one lens can be ruled out by data on a different lens. We explain using two worked examples. One example models 1115+080, 1608+656 (time-delay quads) and 1933+503 (a prospective time-delay system) all together, yielding time-delay predictions for the third lens and a 90%-confidence estimate of 1/H_0=14.6_{-1.7}^{+9.4} Gyr (H_0=67_{-26}^{+9} km/s/Mpc) assuming Omega_M=0.3, Omega_Lambda=0.7. The other example models the time-delay doubles 1520+530, 1600+434, 1830-211, and 2149-275, which gives 1/H_0=14.5_{-1.5}^{+3.3} Gyr (H_0=67_{-13}^{+8} km/s/Mpc). Our second idea is to write the whole modeling software as a highly interactive Java applet, which can be used both for coarse-grained results inside a browser and for fine-grained results on a workstation. Several obstacles come up in trying to implement a numerically-intensive method thus, but w...

  13. The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints

    Science.gov (United States)

    Newman, Andrew B.; Smith, Russell J.; Conroy, Charlie; Villaume, Alexa; van Dokkum, Pieter

    2017-08-01

    We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high-σ ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M */L using lensing and stellar dynamics. We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy & van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2-3σ tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08 M ⊙. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to IMF at low stellar masses (m ≲ 0.3 M ⊙), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M */L relative to the mean matched-σ ETG. We provide the spectra used in this study to facilitate future comparisons.

  14. Plastic Pollution from Ships

    OpenAIRE

    Čulin, Jelena; Bielić, Toni

    2016-01-01

    The environmental impact of shipping on marine environment includes discharge of garbage. Plastic litter is of particular concern due to abundance, resistance to degradation and detrimental effect on marine biota. According to recently published studies, a further research is required to assess human health risk. Monitoring data indicate that despite banning plastic disposal at sea, shipping is still a source of plastic pollution. Some of the measures to combat the problem are discussed.

  15. Uncertainties in pixel-based source reconstruction for gravitationally lensed objects and applications to lensed galaxies

    Science.gov (United States)

    Tagore, Amitpal Singh

    Gravitational lens modeling of spatially resolved sources is a challenging inverse problem that can involve many observational constraints and model parameters. I present a new software package, pixsrc, that works in conjunction with the lensmodel software and builds on established pixel-based source reconstruction (PBSR) algorithms for de-lensing a source and constraining lens model parameters. Using test data, I explore statistical and systematic uncertainties associated with gridding, source regularization, interpolation errors, noise, and telescope pointing. I compare two gridding schemes in the source plane: a fully adaptive grid and an adaptive Cartesian grid. I also consider regularization schemes that minimize derivatives of the source and introduce a scheme that minimizes deviations from an analytic source profile. Careful choice of gridding and regularization can reduce "discreteness noise" in the chi2 surface that is inherent in the pixel-based methodology. With a gridded source, errors due to interpolation need to be taken into account (especially for high S/N data). Different realizations of noise and telescope pointing lead to slightly different values for lens model parameters, and the scatter between different "observations" can be comparable to or larger than the model uncertainties themselves. The same effects create scatter in the lensing magnification at the level of a few percent for a peak S/N of 10. I then apply pixsrc to observations of lensed, high-redshift galaxies. SDSS J0901+1814, is an ultraluminous infrared galaxy at z=2.26 that is also UV-bright, and it is lensed by a foreground group of galaxies at z=0.35. I constrain the lens model using maps of CO(3-2) rotational line emission and optical imaging and apply the lens model to observations of CO(1-0), H-alpha, and [NII] line emission as well. Using the de-lensed images, I calculate properties of the source, such as the gas mass fraction and dynamical mass. Finally, I examine a

  16. Cross-correlation of gravitational lensing from DES Science Verification data with SPT and Planck lensing

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, D.; et al.

    2015-12-14

    We measure the cross-correlation between weak lensing of galaxy images and of the cosmic microwave background (CMB). The effects of gravitational lensing on different sources will be correlated if the lensing is caused by the same mass fluctuations. We use galaxy shape measurements from 139 deg$^{2}$ of the Dark Energy Survey (DES) Science Verification data and overlapping CMB lensing from the South Pole Telescope (SPT) and Planck. The DES source galaxies have a median redshift of $z_{\\rm med} {\\sim} 0.7$, while the CMB lensing kernel is broad and peaks at $z{\\sim}2$. The resulting cross-correlation is maximally sensitive to mass fluctuations at $z{\\sim}0.44$. Assuming the Planck 2015 best-fit cosmology, the amplitude of the DES$\\times$SPT cross-power is found to be $A = 0.88 \\pm 0.30$ and that from DES$\\times$Planck to be $A = 0.86 \\pm 0.39$, where $A=1$ corresponds to the theoretical prediction. These are consistent with the expected signal and correspond to significances of $2.9 \\sigma$ and $2.2 \\sigma$ respectively. We demonstrate that our results are robust to a number of important systematic effects including the shear measurement method, estimator choice, photometric redshift uncertainty and CMB lensing systematics. Significant intrinsic alignment of galaxy shapes would increase the cross-correlation signal inferred from the data; we calculate a value of $A = 1.08 \\pm 0.36$ for DES$\\times$SPT when we correct the observations with a simple IA model. With three measurements of this cross-correlation now existing in the literature, there is not yet reliable evidence for any deviation from the expected LCDM level of cross-correlation, given the size of the statistical uncertainties and the significant impact of systematic errors, particularly IAs. We provide forecasts for the expected signal-to-noise of the combination of the five-year DES survey and SPT-3G.

  17. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plasti...... as a knowledge handbook for laser welding of plastic components. This document should provide the information for all aspects of plastic laser welding and help the design engineers to take all critical issues into consideration from the very beginning of the design phase....

  18. Plastics and health risks.

    Science.gov (United States)

    Halden, Rolf U

    2010-01-01

    By 2010, the worldwide annual production of plastics will surpass 300 million tons. Plastics are indispensable materials in modern society, and many products manufactured from plastics are a boon to public health (e.g., disposable syringes, intravenous bags). However, plastics also pose health risks. Of principal concern are endocrine-disrupting properties, as triggered for example by bisphenol A and di-(2-ethylhexyl) phthalate (DEHP). Opinions on the safety of plastics vary widely, and despite more than five decades of research, scientific consensus on product safety is still elusive. This literature review summarizes information from more than 120 peer-reviewed publications on health effects of plastics and plasticizers in lab animals and humans. It examines problematic exposures of susceptible populations and also briefly summarizes adverse environmental impacts from plastic pollution. Ongoing efforts to steer human society toward resource conservation and sustainable consumption are discussed, including the concept of the 5 Rs--i.e., reduce, reuse, recycle, rethink, restrain--for minimizing pre- and postnatal exposures to potentially harmful components of plastics.

  19. Synaptic Plasticity and Nociception

    Institute of Scientific and Technical Information of China (English)

    ChenJianguo

    2004-01-01

    Synaptic plasticity is one of the fields that progresses rapidly and has a lot of success in neuroscience. The two major types of synaptie plasticity: long-term potentiation ( LTP and long-term depression (LTD are thought to be the cellular mochanisms of learning and memory. Recently, accumulating evidence suggests that, besides serving as a cellular model for learning and memory, the synaptic plasticity involves in other physiological or pathophysiological processes, such as the perception of pain and the regulation of cardiovascular system. This minireview will focus on the relationship between synaptic plasticity and nociception.

  20. Refractive error change and vision improvement in moderate to severe hyperopic amblyopia after spectacle correction: Restarting the emmetropization process?

    Science.gov (United States)

    Chang, Ji Woong

    2017-01-01

    The aims of the study were to develop guidelines for prescribing spectacles for patients with moderate to severe hyperopic amblyopia and to demonstrate how emmetropization progresses. Children with hyperopic amblyopia who had a spherical equivalent of ≥ +4.0 diopters (D) or more were included, while those who had astigmatism of > 2.0 D or anisometropia of > 2.0 D were excluded. The patients were divided into a full correction group and an under-correction group according to the amount of hyperopia correction applied. The under-correction group was further subdivided into a fixed under-correction group and a post-cycloplegic refraction (PCR) under-correction group. The duration of amblyopia treatment and changes in initial hyperopia were compared between the groups. In total, 76 eyes of 38 patients were analyzed in this study. The full correction group and under-correction group were subjected to 5.5 months and 5.9 months of amblyopia treatment, respectively (P = 0.570). However, the PCR under-correction group showed more rapid improvement (2.9 months; P = 0.001). In the under-correction group, initial hyperopia was decreased by -0.28 D and -0.49 D at 6 months and 12 months, respectively, after initial cycloplegic refraction. Moreover, the amount of hyperopia under-correction was correlated with the amount of hyperopia reduction (P = 0.010). The under-correction of moderate to severe hyperopic amblyopia has beneficial effects for treating amblyopia and activating emmetropization. PCR under-correction can more rapidly improve visual acuity, while both fixed under-correction and PCR under-correction can induce emmetropization and effectively reduce initial hyperopia.

  1. Factors influencing immediate post-release survival of spectacled eiders following surgical implantation of transmitters with percutaneous antennae

    Science.gov (United States)

    Sexson, Matthew G.; Mulcahy, Daniel M.; Spriggs, Maria; Myers, Gwen E.

    2014-01-01

    Surgically implanted transmitters are a common method for tracking animal movements. Immediately following surgical implantation, animals pass through a critical recovery phase when behaviors may deviate from normal and the likelihood of individual survival may be reduced. Therefore, data collected during this period may be censored to minimize bias introduced by surgery-related behaviors or mortality. However, immediate post-release mortalities negate a sampling effort and reduce the amount of data potentially collected after the censoring period. Wildlife biologists should employ methods to support an animal’s survival through this period, but factors contributing to immediate post-release survival have not been formally assessed. We evaluated factors that potentially influenced the immediate post-release survival of 56 spectacled eiders (Somateria fischeri) marked with coelomically implanted satellite transmitters with percutaneous antennae in northern Alaska in 2010 and 2011. We modeled survival through the first 14 days following release and assessed the relative importance and effect of 15 covariates hypothesized to influence survival during this immediate post-release period. Estimated daily survival rate increased over the duration of the immediate post-release period; the probability of mortality was greatest within the first 5 days following release. Our top-ranking model included the effect of 2 blood analytes, pH and hematocrit, measured prior to surgical implantation of a transmitter. We found a positive response to pH; eiders exhibiting acidemia (low pH) prior to surgery were less likely to survive the immediate post-release period. We found a curvilinear response to hematocrit; eiders exhibiting extremely low or high pre-surgery hematocrit were also less likely to survive the immediate post-release period. In the interest of maximizing the survival of marked birds following release, hematological data obtained prior to surgical implantation of

  2. Marius Tscherning (1854-1939): his life and work in optical physiology

    DEFF Research Database (Denmark)

    Norn, Mogens; Jensen, O.A.

    2004-01-01

    Ophthalmology, Marius Tscherning, accommodation, colour vision, dark vision, entopic phenomena, medical history, ophthalmophacometer, optic physiology, photometric glasses, spectacle lenses......Ophthalmology, Marius Tscherning, accommodation, colour vision, dark vision, entopic phenomena, medical history, ophthalmophacometer, optic physiology, photometric glasses, spectacle lenses...

  3. Prospective randomized study of clinical performance of 3 aspheric and 2 spherical intraocular lenses in 250 eyes.

    Science.gov (United States)

    Caporossi, Aldo; Martone, Gianluca; Casprini, Fabrizio; Rapisarda, Lorenzo

    2007-09-01

    To compare the quality of vision with aspheric and spherical intraocular lenses (IOLs) in pseudophakic patients. This prospective, comparative, randomized study included 250 eyes of 125 patients with bilateral cataracts. Patients were randomly assigned to receive either IOLs with a spherical biconvex optic (Acrysof SN6OAT [Alcon] or Sensar AR40e [Advanced Medical Optics, AMO]) or IOLs with an aspheric optic (Acrysof IQ SN6OWF [Alcon], Tecnis Z9000 [AMO], or Sofport L161AO [Bausch & Lomb]). Ophthalmologic examination including best spectacle-corrected visual acuity, pupil size, ocular dominance investigation, contrast sensitivity under mesopic and photopic conditions, and wavefront analysis was performed 2 months postoperatively. Aspheric IOLs showed better contrast sensitivity compared to spherical IOLs at spatial frequencies of 6, 12, and 18 cycles per degree (cpd) under photopic conditions and at all spatial frequencies under mesopic conditions. There was no significant difference among the three aspheric IOLs at all spatial frequencies under either photopic or mesopic conditions. Mean total spherical aberration was statistically lower in dominant eyes with aspheric IOLs (0.05 +/- 0.06, 0.11 +/- 0.1, and 0.19 +/- 0.08 pm for the Tecnis Z9000, Acrysof IQ SN6OWF, and Sofport L161AO, respectively) compared with eyes with spherical IOLs (0.62 +/- 0.24 and 0.46 +/- 0.19 microm for the Acrysof SN6OAT and Sensar AR40e, respectively) for a 5-mm pupil diameter. The aspheric IOLs had less wavefront aberrations and performed better under both photopic and mesopic contrast sensitivity compared to the spherical IOLs. These findings confirm it is possible to improve the optical performance of IOLs by modifying the surfaces.

  4. Intrinsic alignment contamination to CMB lensing-galaxy weak lensing correlations from tidal torquing

    Science.gov (United States)

    Larsen, Patricia; Challinor, Anthony

    2016-10-01

    Correlations of galaxy ellipticities with large-scale structure, due to galactic tidal interactions, provide a potentially significant contaminant to measurements of cosmic shear. However, these intrinsic alignments are still poorly understood for galaxies at the redshifts typically used in cosmic shear analyses. For spiral galaxies, it is thought that tidal torquing is significant in determining alignments resulting in zero correlation between the intrinsic ellipticity and the gravitational potential in linear theory. Here, we calculate the leading-order correction to this result in the tidal-torque model from non-linear evolution, using second-order perturbation theory, and relate this to the contamination from intrinsic alignments to the recently measured cross-correlation between galaxy ellipticities and the cosmic microwave background (CMB) lensing potential. On the scales relevant for CMB lensing observations, the squeezed limit of the gravitational bispectrum dominates the correlation. Physically, the large-scale mode that sources CMB lensing modulates the small-scale power and hence the intrinsic ellipticity, due to non-linear evolution. We find that the angular cross-correlation from tidal torquing has a very similar scale dependence as in the linear alignment model, believed to be appropriate for elliptical galaxies. The amplitude of the cross-correlation is predicted to depend strongly on the formation redshift, being smaller for galaxies that formed at higher redshift when the bispectrum of the gravitational potential was smaller. Finally, we make simple forecasts for constraints on intrinsic alignments from the correlation of forthcoming cosmic shear measurements with current CMB lensing measurements. We note that cosmic variance can be significantly reduced in measurements of the difference in the intrinsic alignments for elliptical and spiral galaxies if these types can be separated (e.g. using colour).

  5. Full covariance of CMB and lensing reconstruction power spectra

    Science.gov (United States)

    Peloton, Julien; Schmittfull, Marcel; Lewis, Antony; Carron, Julien; Zahn, Oliver

    2017-02-01

    CMB and lensing reconstruction power spectra are powerful probes of cosmology. However, they are correlated, since the CMB power spectra are lensed, and the lensing reconstruction is constructed using CMB multipoles. We perform a full analysis of the auto- and cross-covariances, including polarization power spectra and minimum-variance lensing estimators, and compare with simulations of idealized future CMB-S4 observations. Covariances sourced by fluctuations in the unlensed CMB and instrumental noise can largely be removed by using a realization-dependent subtraction of lensing reconstruction noise, leaving a relatively simple covariance model that is dominated by lensing-induced terms and well described by a small number of principal components. The correlations between the CMB and lensing power spectra will be detectable at the level of ˜5 σ for a CMB-S4 mission, and neglecting them could underestimate some parameter error bars by several tens of percent. However, we found that the inclusion of external priors or data sets to estimate parameter error bars can make the impact of the correlations almost negligible.

  6. Reconstruction of lensing from the cosmic microwave background polarization

    CERN Document Server

    Hirata, C M; Hirata, Christopher M.; Seljak, Uros

    2003-01-01

    Gravitational lensing of the cosmic microwave background (CMB) polarization field has been recognized as a potentially valuable probe of the cosmological density field. We apply likelihood-based techniques to the problem of lensing of CMB polarization and show that if the B-mode polarization is mapped, then likelihood-based techniques allow significantly better lensing reconstruction than is possible using the previous quadratic estimator approach. With this method the ultimate limit to lensing reconstruction is not set by the lensed CMB power spectrum. Second-order corrections are known to produce a curl component of the lensing deflection field that cannot be described by a potential; we show that this does not significantly affect the reconstruction at noise levels greater than 0.25 microK arcmin. The reduction of the mean squared error in the lensing reconstruction relative to the quadratic method can be as much as a factor of two at noise levels of 1.4 microK arcmin to a factor of ten at 0.25 microK arcm...

  7. Galaxy-Galaxy Weak Lensing Measurements from SDSS: I. Image Processing and Lensing signals

    CERN Document Server

    Luo, Wentao; Zhang, Jun; Tweed, Dylan; Fu, Liping; Mo, H J; Bosch, Frank C van den; Shu, Chenggang; Li, Ran; Li, Nan; Liu, Xiangkun; Pan, Chuzhong; Wang, Yiran; Radovich, Mario

    2016-01-01

    As the first paper in a series on the study of the galaxy-galaxy lensing from Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we present our image processing pipeline that corrects the systematics primarily introduced by the Point Spread Function (PSF). Using this pipeline, we processed SDSS DR7 imaging data in $r$ band and generated a background galaxy catalog containing the shape information of each galaxy. Based on our own shape measurements of the galaxy images from SDSS DR7, we extract the galaxy-galaxy (GG) lensing signals around foreground spectroscopic galaxies binned in different luminosity and stellar mass. The overall signals are in good agreement with those obtained by \\citet{Mandelbaum2005, Mandelbaum2006} from the SDSS DR4. The results in this paper with higher signal to noise ratio is due to the larger survey area than SDSS DR4, confirm that more luminous/massive galaxies bear stronger GG lensing signal. We also divide the foreground galaxies into red/blue and star forming/quenched subsampl...

  8. GALAXY SCALE LENSES IN THE RCS2. I. FIRST CATALOG OF CANDIDATE STRONG LENSES

    Energy Technology Data Exchange (ETDEWEB)

    Anguita, T. [Centro de Astro-Ingenieria, Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Barrientos, L. F. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago (Chile); Gladders, M. D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Faure, C. [Laboratoire d' Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Obervatoire de Sauverny, CH-1290 Versoix (Switzerland); Yee, H. K. C.; Gilbank, D. G. [Department of Astronomy and Astrophysics, University of Toronto, 50 St George Street, Toronto, Ontario, M5S 3H4 (Canada)

    2012-04-01

    We present the first galaxy scale lens catalog from the second Red-Sequence Cluster Survey. The catalog contains 60 lensing system candidates comprised of Luminous Red Galaxy (LRG) lenses at 0.2 {approx}< z {approx}< 0.5 surrounded by blue arcs or apparent multiple images of background sources. The catalog is a valuable complement to previous galaxy-galaxy lens catalogs as it samples an intermediate lens redshift range and is composed of bright sources and lenses that allow easy follow-up for detailed analysis. Mass and mass-to-light ratio estimates reveal that the lens galaxies are massive ( M-bar {approx} 5.5 Multiplication-Sign 10{sup 11} [M{sub Sun} h{sup -1}]) and rich in dark matter (M/L-bar{approx} 14 [M{sub Sun }/L{sub Sun ,B} h]). Even though a slight increasing trend in the mass-to-light ratio is observed from z = 0.2 to z = 0.5, current redshift and light profile measurements do not allow stringent constraints on the mass-to-light ratio evolution of LRGs.

  9. Differential mortality of male spectacled eiders (Somateria fischeri) and king eiders (Somateria spectabilis) subsequent to anesthesia with propofol, bupivacaine, and ketoprofen

    Science.gov (United States)

    Mulcahy, Daniel M.; Tuomi, Pamela A.; Larsen, R.S.

    2003-01-01

    Twenty free-ranging spectacled eiders (Somateria fischeri; 10 male, 10 female), 11 free-ranging king eiders (Somateria spectabilis; 6 male, 5 female), and 20 female common eiders (Somateria mollissima) were anesthetized with propofol, bupivacaine, and ketoprofen for the surgical implantation of satellite transmitters. Propofol was given to induce and maintain anesthesia (mean total dose, 26.2-45.6 mg/kg IV), bupivacaine (2-10 mg/kg SC) was infused into the incision site for local analgesia, and ketoprofen (2-5 mg/kg IM) was given at the time of surgery for postoperative analgesia. Four of 10 male spectacled eiders and 5 of 6 male king eiders died within 1-4 days after surgery. None of the female spectacled or common eiders and only 1 of the 5 female king eiders died during the same postoperative period. Histopathologic findings in 2 dead male king eiders were severe renal tubular necrosis, acute rhabdomyolysis, and mild visceral gout. Necropsy findings in 3 other dead male king eiders were consistent with visceral gout. We suspect that the perioperative use of ketoprofen caused lethal renal damage in the male eiders. Male eiders may be more susceptible to renal damage than females because of behavioral differences during their short stay on land in mating season. The combination of propofol, bupivacaine, and ketoprofen should not be used to anesthetize free-ranging male eiders, and nonsteroidal anti-inflammatory drugs should not be used perioperatively in any bird that may be predisposed to renal insufficiency.

  10. Negative Refraction Does Not Make Perfect Lenses

    CERN Document Server

    Yang, Weiguo

    2013-01-01

    The widely-accepted theoretical treatment of the electromagnetic boundary problem of evanescent wave transfer at an interface between a normal medium of n=1 and an ideal negative index medium of n=-1 neglects the non-zero induced surface current and charge densities at the interface and is self-inconsistent. We re-solve the electromagnetic boundary problem by taking into account the non-zero induced surface current and charge densities that have been neglected so far by others. We give the exact induced surface current and charge distributions for this special case and solve the refracted and reflected fields analytically using Green's function method. The self-consistent solution yields a transmission coefficient of 1 and reflection coefficient of 0 for all evanescent waves. Accordingly, we found that, on the contrary to the popular belief, negative index of refraction does not make perfect lenses.

  11. Designing novel anisotropic lenses with transformation optics

    Science.gov (United States)

    Jiang, Wei Xiang; Bao, Di; Cui, Tie Jun

    2016-04-01

    Transformation optics (TO), based on the formally invariant property of Maxwell’s equations, has provided a powerful strategy to design anisotropic or nearly-isotropic devices, in both time-varied and static fields. In this paper, we present and investigate the negative refraction or reflection phenomena by positive-index anisotropic materials based on transformation-optics design. First, we propose and design an inhomogeneous transformed planar lens, in which we will show the negative-refraction-like properties of transformation media. Secondly, we present a homogeneous transformed lens based on linear spatial transformation, in which we will reveal the negative-reflection properties of positive transformation media. Both transformed lenses have unusual properties which are different from those in natural materials.

  12. Mechanical properties of intra-ocular lenses

    Science.gov (United States)

    Ehrmann, Klaus; Kim, Eon; Parel, Jean-Marie

    2008-02-01

    Cataract surgery usually involves the replacement of the natural crystalline lens with a rigid or foldable intraocular lens to restore clear vision for the patient. While great efforts have been placed on optimising the shape and optical characteristics of IOLs, little is know about the mechanical properties of these devices and how they interact with the capsular bag once implanted. Mechanical properties measurements were performed on 8 of the most commonly implanted IOLs using a custom build micro tensometer. Measurement data will be presented for the stiffness of the haptic elements, the buckling resistance of foldable IOLs, the dynamic behaviour of the different lens materials and the axial compressibility. The biggest difference between the lens types was found between one-piece and 3-piece lenses with respect to the flexibility of the haptic elements

  13. Cosmological parameters from lenses distance ratio

    CERN Document Server

    Cardone, Vincenzo F; Scudellaro, Paolo

    2015-01-01

    Strong lensing provides popular techniques to investigate the mass distribution of intermediate redshift galaxies, testing galaxy evolution and formation scenarios. It especially probes the background cosmic expansion, hence constraining cosmological parameters. The measurement of Einstein radii and central velocity dispersions indeed allows to trace the ratio D_s/D_ls between the distance D_s from the observer to the source and the distance D_ls from the lens to the source. We present an improved method to explicitly include the two - component structure in the galaxy lens modeling, in order to analyze the role played by the redshift and the model dependence on a nuisance parameter, F_E, which is usually marginalized in the cosmological applications. We show how to deal with these problems and carry on a Fisher matrix analysis to infer the accuracy on cosmological parameters achieved by this method.

  14. Wavefront shaping for opaque cylindrical lenses

    CERN Document Server

    Di Battista, Diego; Ancora, Daniele; Lemonaki, Krystalia; Liapis, Evangelos; Tzortzakis, Stelios; Zacharakis, Giannis

    2016-01-01

    Wavefront shaping has revolutionized the concepts of optical imaging and focusing. Contrary to what was believed, strong scattering in the optical paths can be exploited in favor of light focusing through turbid media and ultimately improve optical imaging and light manipulation capabilities. The use of light shapers and appropriately engineered scattering structures, i.e. opaque lenses enables the production of nano-scale confined foci and of extended fields of view. Exploiting this concept we fabricate configurable scattering structures by direct femtosecond laser writing. The properly shaped light trespassing the customized structure, a photonic lattice of parallel rods, forms a light-sheet at user defined positions. We demonstrate that our technique enables light-sheets with sub-micron resolution and extended depth of focus, a significant advantage when compared to the existing free space systems. Moreover, our approach permits to focus light of different wavelengths onto the same defined position without...

  15. Microfabrication of hard x-ray lenses

    DEFF Research Database (Denmark)

    Stöhr, Frederik

    heights and improved uniformity compared to what is currently available. To this end, established fabrication procedures are improved and the toolbox used for lens development is enriched. The central theme of this thesis is x-ray microscopy (XRM). As a spearhead of today’s materials research it provides...... in turn asks for highly precise metrology. Therefore, a mix of techniques including optical profilometry and atomic force microscopy (AFM) has been used to obtain reliable information about the detailed three-dimensional shapes of the lenses. Adequate sample preparation and measuring procedures have been...... of space for sample surroundings and ensure low-divergent and wide x-ray beams with narrow waists. Both results are substantial improvements to what was available at the start of this thesis work. The challenge of making x-ray objectives in silicon by interdigitation of lenslets alternately focusing...

  16. Data Mining for Gravitationally Lensed Quasars

    CERN Document Server

    Agnello, Adriano; Treu, Tommaso; Marshall, Philip J

    2014-01-01

    Gravitationally lensed (GL) quasars are brighter than their unlensed counterparts and produce images with distinctive morphological signatures. Past searches and target selection algorithms, in particular the Sloan Quasar Lens Search (SQLS), have relied on basic morphological criteria, which were applied to samples of bright, spectroscopically confirmed quasars. The SQLS techniques are not sufficient for searching into new surveys (e.g. DES, PS1, LSST), because spectroscopic information is not readily available and the large data volume requires higher purity in target/candidate selection. We carry out a systematic exploration of machine learning techniques and demonstrate that a two step strategy can be highly effective. In the first step we use catalog-level information ($griz$+WISE magnitudes, second moments) to preselect targets, using artificial neural networks. The accepted targets are then inspected with pixel-by-pixel pattern recognition algorithms (Gradient-Boosted Trees), to form a final set of cand...

  17. Weak lensing using only galaxy position angles

    CERN Document Server

    Whittaker, Lee; Battye, Richard

    2013-01-01

    We develop a method for performing a weak lensing analysis using only measurements of galaxy position angles. By analyzing the statistical properties of the galaxy orientations given a known intrinsic ellipticity distribution, we show that it is possible to obtain estimates of the shear by minimizing a $\\chi^2$ statistic. The method is demonstrated using simulations where the components of the intrinsic ellipticity are taken to be Gaussian distributed. Uncertainties on the position angle measurements introduce a bias into the shear estimates which can be reduced to negligible levels by introducing a correction term into the formalism. We generalize our approach by developing an algorithm to obtain direct shear estimators given any azimuthally symmetric intrinsic ellipticity distribution. We demonstrate this technique by applying it to simulations where the ellipticities are taken to follow a log-normal distribution. We compare the performance of the position angle only method with the standard method based on...

  18. Tunable focalizers: axicons, lenses, and axilenses

    Science.gov (United States)

    Ojeda-Castañeda, Jorge; Gómez-Sarabia, Cristina M.; Ledesma, Sergio

    2013-09-01

    We propose the use of a pair of phase masks, which have both radial and angular variations, for implementing several varifocal devices. One mask of the proposed pair has a complex amplitude transmittance that is the complex conjugate of the other member of the pair. We show that the overall complex amplitude transmittance has only a radial variation after introducing an in-plane rotation, say by an angle β, between the members of the pair. However, we note that the optical power is proportional to the rotation angle β. As examples of the proposed method, we show that the refractive pair is useful for implementing varifocal lenses, tunable axicons, controllable axilenses, as well as annularly distributed focalizers.

  19. A Lens Mapping Algorithm for Weak Lensing

    CERN Document Server

    Saini, T D; Saini, Tarun Deep; Raychaudhury, Somak

    2001-01-01

    We develop an algorithm for the reconstruction of the two-dimensional massdistribution of a cluster of galaxies from the observable distortion ofbackground galaxies. From the measured reduced shear gamma_i/(1-kappa) the lensmapping is directly obtained, from which a mass distribution is derived. Thisis unlike other methods where the convergence (kappa) is first obtained. Weshow that this method works best for sub-critical lenses but can be applied toa critical lens away from the critical lines. For finite fields the usualmass-sheet degeneracy is shown to exist in this method as well. We suggest aniterative scheme to remove the mass-sheet degeneracy for the case of asub-critical lens, in the absence of a substantial external shear. The sametechnique can be used with additional information for the case of a criticallens as well. A scheme to reduce the effects of noise is also suggested.

  20. Finding strong lenses in CFHTLS using convolutional neural networks

    Science.gov (United States)

    Jacobs, C.; Glazebrook, K.; Collett, T.; More, A.; McCarthy, C.

    2017-10-01

    We train and apply convolutional neural networks, a machine learning technique developed to learn from and classify image data, to Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) imaging for the identification of potential strong lensing systems. An ensemble of four convolutional neural networks was trained on images of simulated galaxy-galaxy lenses. The training sets consisted of a total of 62 406 simulated lenses and 64 673 non-lens negative examples generated with two different methodologies. An ensemble of trained networks was applied to all of the 171 deg2 of the CFHTLS wide field image data, identifying 18 861 candidates including 63 known and 139 other potential lens candidates. A second search of 1.4 million early-type galaxies selected from the survey catalogue as potential deflectors, identified 2465 candidates including 117 previously known lens candidates, 29 confirmed lenses/high-quality lens candidates, 266 novel probable or potential lenses and 2097 candidates we classify as false positives. For the catalogue-based search we estimate a completeness of 21-28 per cent with respect to detectable lenses and a purity of 15 per cent, with a false-positive rate of 1 in 671 images tested. We predict a human astronomer reviewing candidates produced by the system would identify 20 probable lenses and 100 possible lenses per hour in a sample selected by the robot. Convolutional neural networks are therefore a promising tool for use in the search for lenses in current and forthcoming surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope.

  1. Halos of Plastic

    Institute of Scientific and Technical Information of China (English)

    Maya Reid

    2012-01-01

    The halos that span South Africa's coastline are anything but angelic. Fanning out around four major urban centers-Cape Town, Port Elizabeth, East London and Durban-they are made up of innumerable bits and pieces of plastic. As a form of pollution, their shelflife is unfathomable. Plastic is essentially chemically inactive. It's designed to never break down.

  2. Biodegradation of plastics.

    Science.gov (United States)

    Shimao, M

    2001-06-01

    Widespread studies on the biodegradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of genes for synthetic polymer-degrading enzymes.

  3. Aberrations of Gradient-Index Lenses.

    Science.gov (United States)

    Matthews, A. L.

    Available from UMI in association with The British Library. In this thesis, the primary aberrations of lenses with a radial focussing gradient-of-index are analysed. Such a lens has a refractive index profile which decreases continuously and radially outward from the optical axis, so that the surfaces of constant refractive index are circular cylinders which are coaxial with the optical axis. Current applications of these lenses include photocopiers, medical endoscopes, telecommunications systems and compact disc systems. Closed formulae for the primary wavefront aberrations for a gradient-index lens with curved or plane entry and exit faces are obtained from the differential equations of such a lens to assess the primary transverse ray aberrations that it introduces. Identical expressions are then obtained by using the difference in optical path length produced between two rays by the lens. This duplication of the derivations of the primary wavefront aberrations acts as a confirmation of the validity of the expressions. One advantage of these equations is that the contributions due to the primary spherical aberration, coma, astigmatism, field curvature and distortion can be assessed individually. A Fortran 77 program has been written to calculate each of these individual contributions, the total primary wavefront aberrations and the primary transverse ray aberrations. Further confirmation of the validity of the expressions is obtained by using this program to show that the coma and distortion were both zero for fully symmetric systems working at unit magnification. The program is then used to assess the primary wavefront aberrations for a gradient-index lens which is currently of interest to the telecommunications industry. These results are compared with values obtained using a finite ray-tracing program for the total wavefront aberrations. This shows that the primary wavefront aberrations are the completely dominant contribution to the total wavefront

  4. Weak lensing galaxy cluster field reconstruction

    Science.gov (United States)

    Jullo, E.; Pires, S.; Jauzac, M.; Kneib, J.-P.

    2014-02-01

    In this paper, we compare three methods to reconstruct galaxy cluster density fields with weak lensing data. The first method called FLens integrates an inpainting concept to invert the shear field with possible gaps, and a multi-scale entropy denoising procedure to remove the noise contained in the final reconstruction, that arises mostly from the random intrinsic shape of the galaxies. The second and third methods are based on a model of the density field made of a multi-scale grid of radial basis functions. In one case, the model parameters are computed with a linear inversion involving a singular value decomposition (SVD). In the other case, the model parameters are estimated using a Bayesian Monte Carlo Markov Chain optimization implemented in the lensing software LENSTOOL. Methods are compared on simulated data with varying galaxy density fields. We pay particular attention to the errors estimated with resampling. We find the multi-scale grid model optimized with Monte Carlo Markov Chain to provide the best results, but at high computational cost, especially when considering resampling. The SVD method is much faster but yields noisy maps, although this can be mitigated with resampling. The FLens method is a good compromise with fast computation, high signal-to-noise ratio reconstruction, but lower resolution maps. All three methods are applied to the MACS J0717+3745 galaxy cluster field, and reveal the filamentary structure discovered in Jauzac et al. We conclude that sensitive priors can help to get high signal-to-noise ratio, and unbiased reconstructions.

  5. Analysis of presbyopia and spectacle correction in South Asia%南亚4国老视配镜情况调查分析

    Institute of Scientific and Technical Information of China (English)

    崔蓓; 刘百臣; 卢成戎

    2015-01-01

    目的:通过对南亚马尔代夫、巴基斯坦、孟加拉国、缅甸4国老视就诊者配镜的分析,总结其老视配镜的规律,为今后进行南亚国家医疗服务提供参考。方法根据就诊者中配镜人员(818名)年龄分为2组,依托866医院船诊治平台、前出至当地医疗机构的眼科门诊对各个年龄段老视配镜情况及老视存在意识和态度进行分析,并随即询问。结果年龄32~44岁佩戴老视镜+1.0~+2.5 DS,45~54岁佩戴老视镜+2.0~+3.5 DS;818名中仅有52.1%的人认为老视是存在的,有31.2%的人认为老视即年老。结论南亚4国老视年龄出现较早,对低度数老视镜需求较大;中年人出现老视是人生自然生理过程,应当增强意识,及时佩戴老视镜。%Objective The aim of our work was to evaluate presbyopia spectacles among mid-age population in oceangoing medical service of South Asia Maldives, Pakistan, Bangladesh and Myanmar, and to provide reference for medical services in South Asia country in future prolonged sea mission.Methods The mid-age population was grouped by age.Data were obtained from the Navy hospital ship ( No.866) .Results Thirty-two —forty-four years old people required the spec-tacles of +1.0—+2.5 DS , 45—54 years old people required the spectacles of +2.5—+3.5 DS. 52.1%of 818 peoples admitted the presence of presbyopia, 31.2%of them thought it was because of aging.Conclusion The presbyopia could appear early in people of South Asia countries, which requires more attention and timely wearing of presbyopia spectacles.

  6. Vom grand spectacle zur great season. Das Pariser Théâtre du Châtelet als Raum musikalischer Produktion und Rezeption (1862-1914

    Directory of Open Access Journals (Sweden)

    Gesa zur Nieden

    2009-12-01

    Full Text Available Das Pariser Théâtre du Châtelet ist als Raum musikalischer Produktion und Rezeption für das Pariser Musikleben um 1900 äußerst repräsentativ – und das sowohl in musik- als auch kulturgeschichtlicher Hinsicht: Es wurde 1862 unter Napoleon III. während der Pariser Haussmannisierung als großes Volkstheater für das operettenhafte Genre des grand spectacle gebaut, das sich vor allem durch seine sensationellen Bühnenbilder auszeichnete und von Potpourris aus beliebten Chansons und Arien begleitet w...

  7. Bacterial populations on 30-night extended wear silicone hydrogel lenses.

    Science.gov (United States)

    Keay, L; Willcox, M D; Sweeney, D F; Morris, C A; Harmis, N; Corrigan, K; Holden, B A

    2001-01-01

    Ocular infection and inflammation during hydrogel lens extended wear is often associated with colonization of the lenses with bacteria. This study compares colonization of a high Dk silicone hydrogel contact lens (lotrafilcon A) worn on a 30-night extended wear basis to a low Dk HEMA-based lens (etafilcon A) worn on a 6-night extended wear schedule. The group wearing the low Dk/t soft contact lens (n = 63) replaced their lenses weekly and the group wearing high Dk/t soft contact lenses replaced their lenses monthly (n = 64). Lens allocation was assigned randomly at enrollment. Worn lenses, from one eye only, were collected aseptically and placed in sterile vials. Microbial growth on various media was enumerated and the number of colony forming units (cfu) per lens was calculated in categories of normal ocular microbiota (such as coagulase-negative staphylococci and Propionibacterium spp.) and known ocular pathogens (such as Staphylococcus aureus and gram-negative bacteria). The proportion of samples colonized with these bacteria and the extent of colonization were compared between the two groups. The proportion of sterile lenses was calculated, and the types of bacteria on each lens group were compared. No differences between the low and high Dk/t Soft contact lens groups were observed in the proportion of lenses colonized by Propionibacterium spp. (48% vs 43%, P = 0.4) or coagulase-negative staphylococci (47% vs 54%, P = 0.2). Similarly, no differences were found for lenses colonized by S. aureus (0% vs 2%, P = 0.1) or gram-negative bacteria (3% vs 2%, P = 0.8). The types of bacteria isolated from the high and low Dk/t lenses were similar. There were no differences in the number of sterile samples (28% vs 27%, P = 0.8) from each group. These findings suggest that high Dk/t silicone hydrogel materials are colonized by similar numbers and types of microorganisms during extended wear compared to HEMA-based material. Most lenses were colonized by commensal bacteria

  8. DESIGNERS’ KNOWLEDGE IN PLASTICS

    DEFF Research Database (Denmark)

    Eriksen, Kaare

    2013-01-01

    The Industrial designers’ knowledge in plastics materials and manufacturing principles of polymer products is very important for the innovative strength of the industry, according to a group of Danish plastics manufacturers, design students and practicing industrial designers. These three groups...... answered the first Danish national survey, PD13[1], investigating the importance of industrial designers’ knowledge in plastics and the collaboration between designers and the polymer industry. The plastics industry and the industrial designers collaborate well, but both groups frequently experience...... that the designers’ lack of knowledge concerning polymer materials and manufacturing methods can be problematic or annoying, and design students from most Danish design universities express the need for more contact with the industry and more competencies and tools to handle even simple topics when designing plastic...

  9. Consciousness and neural plasticity

    DEFF Research Database (Denmark)

    In contemporary consciousness studies the phenomenon of neural plasticity has received little attention despite the fact that neural plasticity is of still increased interest in neuroscience. We will, however, argue that neural plasticity could be of great importance to consciousness studies....... If consciousness is related to neural processes it seems, at least prima facie, that the ability of the neural structures to change should be reflected in a theory of this relationship "Neural plasticity" refers to the fact that the brain can change due to its own activity. The brain is not static but rather...... the relation between consciousness and brain functions. If consciousness is connected to specific brain structures (as a function or in identity) what happens to consciousness when those specific underlying structures change? It is therefore possible that the understanding and theories of neural plasticity can...

  10. Gravitational lensing of the CMB: A Feynman diagram approach

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Elizabeth E.; Manohar, Aneesh V. [Department of Physics, University of California at San Diego, La Jolla, CA 92093 (United States); Waalewijn, Wouter J. [Nikhef, Theory Group, Science Park 105, 1098 XG, Amsterdam (Netherlands); ITFA, University of Amsterdam, Science Park 904, 1018 XE, Amsterdam (Netherlands); Yadav, Amit P.S., E-mail: ayadav@physics.ucsd.edu [Department of Physics, University of California at San Diego, La Jolla, CA 92093 (United States)

    2014-09-07

    We develop a Feynman diagram approach to calculating correlations of the Cosmic Microwave Background (CMB) in the presence of distortions. As one application, we focus on CMB distortions due to gravitational lensing by Large Scale Structure (LSS). We study the Hu–Okamoto quadratic estimator for extracting lensing from the CMB and derive the noise of the estimator up to O(ϕ{sup 4}) in the lensing potential ϕ. By identifying the diagrams responsible for the previously noted large O(ϕ{sup 4}) term, we conclude that the lensing expansion does not break down. The convergence can be significantly improved by a reorganization of the ϕ expansion. Our approach makes it simple to obtain expressions for quadratic estimators based on any CMB channel, including many previously unexplored cases. We briefly discuss other applications to cosmology of this diagrammatic approach, such as distortions of the CMB due to patchy reionization, or due to Faraday rotation from primordial axion fields/.

  11. Gravitational lensing of the CMB: A Feynman diagram approach

    Directory of Open Access Journals (Sweden)

    Elizabeth E. Jenkins

    2014-09-01

    Full Text Available We develop a Feynman diagram approach to calculating correlations of the Cosmic Microwave Background (CMB in the presence of distortions. As one application, we focus on CMB distortions due to gravitational lensing by Large Scale Structure (LSS. We study the Hu–Okamoto quadratic estimator for extracting lensing from the CMB and derive the noise of the estimator up to O(ϕ4 in the lensing potential ϕ. By identifying the diagrams responsible for the previously noted large O(ϕ4 term, we conclude that the lensing expansion does not break down. The convergence can be significantly improved by a reorganization of the ϕ expansion. Our approach makes it simple to obtain expressions for quadratic estimators based on any CMB channel, including many previously unexplored cases. We briefly discuss other applications to cosmology of this diagrammatic approach, such as distortions of the CMB due to patchy reionization, or due to Faraday rotation from primordial axion fields.

  12. Weak Lensing Peak Finding: Estimators, Filters, and Biases

    CERN Document Server

    Schmidt, Fabian

    2010-01-01

    Large catalogs of shear-selected peaks have recently become a reality. In order to properly interpret the abundance and properties of these peaks, it is necessary to take into account the effects of the clustering of source galaxies, among themselves and with the lens. In addition, the preferred selection of lensed galaxies in a flux- and size-limited sample leads to fluctuations in the apparent source density which correlate with the lensing field (lensing bias). In this paper, we investigate these issues for two different choices of shear estimators which are commonly in use today: globally-normalized and locally-normalized estimators. While in principle equivalent, in practice these estimators respond differently to systematic effects such as lensing bias and cluster member dilution. Furthermore, we find that which estimator is statistically superior depends on the specific shape of the filter employed for peak finding; suboptimal choices of the estimator+filter combination can result in a suppression of t...

  13. Strong biases in infrared-selected gravitational lenses

    CERN Document Server

    Serjeant, Stephen

    2012-01-01

    Bright submm-selected galaxies have been found to be a rich source of strong gravitational lenses. However, strong gravitational lensing of extended sources leads inevitably to differential magnification. In this paper I quantify the effect of differential magnification on simulated far-infrared and submm surveys of strong gravitational lenses, using a foreground population of Navarro-Frenk-White plus de Vaucouleurs' density profiles, with a model source resembling the Cosmic Eyelash and QSO J1148+5251. Some emission line diagnostics are surprisingly unaffected by differential magnification effects: for example, the bolometric fractions of [C II] 158um and CO(J=1-0), often used to infer densities and ionisation parameters, have typical differential magnification effects that are smaller than the measurement errors. However, the CO ladder itself is significantly affected. Far-infrared lensed galaxy surveys (e.g. at 60um) strongly select for high-redshift galaxies with caustics close to AGN, boosting the appare...

  14. The Danger of Using Tap Water with Contact Lenses

    Science.gov (United States)

    Acanthamoeba is a microbe that is very common in tap water. It has two forms: the trophozoite and the cyst. These trophozoites and cysts can stick to the surface of your contact lenses and then infect your eye.

  15. Weak gravitational lensing by fourth order gravity black holes

    CERN Document Server

    Horváth, Zsolt; Hobill, David; Capozziello, Salvatore; De Laurentis, Mariafelicia

    2012-01-01

    We discuss weak lensing characteristics for black holes in a fourth order f(R) gravity theory, characterized by a gravitational strength parameter $\\sigma $ and a distance scale $r_{c}$. Above $r_{c}$ gravity is strengthened and as a consequence weak lensing features are modified compared to the Schwarzschild case. We find a critical impact parameter (depending upon $r_{c}$) for which the behavior of the deflection angle changes. Using the Virbhadra-Ellis lens equation we improve the computation of the image positions, Einstein ring radii, magnification factors and the magnification ratio. We demonstrate that the magnification ratio as function of image separation has a different power-law dependence for each parameter $\\sigma $. As these are the lensing quantities most conveniently determined by direct measurements, future lensing surveys will be able to constrain the parameter $\\sigma $ based on this prediction.

  16. Microstructured gradient-index lenses for THz photoconductive antennas

    Science.gov (United States)

    Brincker, Mads; Karlsen, Peter; Skovsen, Esben; Søndergaard, Thomas

    2016-02-01

    A new type of substrate lens for photoconductive antennas (PCA's) based on sub-wavelength microstructuring is presented and studied theoretically by the use of Greens function integral equation methods (GFIEM's). By etching sub-wavelength trenches into a flat substrate, the effective dielectric constant can be designed to function like a gradient index (GRIN) lens. The proposed GRIN substrate lenses have sub-mm dimension, which is smaller than the dimensions of a typical hyper-hemispherical substrate lens (HSL), and could enable fabrication of arrays of closely packed PCA's with individual lenses integrated directly into the PCA substrate. The performance of different GRIN lenses is compared to a HSL and shown to be comparable with regards to the terahertz radiation extraction efficiency, and it is shown that the collimating properties of these GRIN lenses can be tailored by changing the parameters used for microstructuring.

  17. Identity and attribution as lenses to understand the relationship ...

    African Journals Online (AJOL)

    Identity and attribution as lenses to understand the relationship between transition to ... Irrespective of social class, those who attributed academic performance to factors outside their ... Suggestions are also made for further large-scale studies.

  18. Reconstruction of Gravitational Lensing Using WMAP 7-Year Data

    CERN Document Server

    Feng, Chang; Paar, Hans P; Zahn, Oliver

    2011-01-01

    Gravitational lensing by large scale structure introduces non-Gaussianity into the Cosmic Microwave Background and imprints a new observable, which can be used as a cosmological probe. We apply a four-point estimator to the Wilkinson Microwave Anisotropy Probe (WMAP) 7-year coadded temperature maps alone to reconstruct the gravitational lensing signal. The Gaussian bias is simulated and subtracted, and the higher order bias is investigated. We measure a gravitational lensing signal with a statistical amplitude of $\\mathcal {C}$ = $1.27\\pm 0.98$ using all the correlations of the W- and V-band Differencing Assemblies (DAs). We therefore conclude that WMAP 7-year data alone, can not detect lensing.

  19. Higher order moments of lensing convergence - I. Estimate from simulations

    CERN Document Server

    Vicinanza, M; Maoli, R; Scaramella, R; Er, X

    2016-01-01

    Large area lensing surveys are expected to make it possible to use cosmic shear tomography as a tool to severely constrain cosmological parameters. To this end, one typically relies on second order statistics such as the two - point correlation fucntion and its Fourier counterpart, the power spectrum. Moving a step forward, we wonder whether and to which extent higher order stastistics can improve the lensing Figure of Merit (FoM). In this first paper of a series, we investigate how second, third and fourth order lensing convergence moments can be measured and use as probe of the underlying cosmological model. We use simulated data and investigate the impact on moments estimate of the map reconstruction procedure, the cosmic variance, and the intrinsic ellipticity noise. We demonstrate that, under realistic assumptions, it is indeed possible to use higher order moments as a further lensing probe.

  20. Dynamic contact angle analysis of silicone hydrogel contact lenses.

    Science.gov (United States)

    Read, Michael Leonard; Morgan, Philip Bruce; Kelly, Jeremiah Michael; Maldonado-Codina, Carole

    2011-07-01

    Contact angle measurements are used to infer the clinical wetting characteristics of contact lenses. Such characterization has become more commonplace since the introduction of silicone hydrogel contact lens materials, which have been associated with reduced in vivo wetting due to the inclusion of siloxane-containing components. Using consistent methodology and a single investigator, advancing and receding contact angles were measured for 11 commercially available silicone hydrogel contact lens types with a dynamic captive bubble technique employing customized, fully automated image analysis. Advancing contact angles were found to range between 20° and 72° with the lenses falling into six statistically discrete groupings. Receding contact angles fell within a narrower range, between 17° and 22°, with the lenses segregated into three groups. The relationship between these laboratory measurements and the clinical performance of the lenses requires further investigation.

  1. Galaxy-galaxy lensing estimators and their covariance properties

    CERN Document Server

    Singh, Sukhdeep; Seljak, Uroš; Slosar, Anže; Gonzalez, Jose Vazquez

    2016-01-01

    We study the covariance properties of real space correlation function estimators -- primarily galaxy-shear correlations, or galaxy-galaxy lensing -- using SDSS data for both shear catalogs and lenses (specifically the BOSS LOWZ sample). Using mock catalogs of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the density field instead of the over-density field, and that this leads to a significant error increase due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the over-density, we find that the errors are dominated by the shape noise and lens clustering, that empirically estimated covarianc...

  2. Direct probe of dark energy through gravitational lensing effect

    Science.gov (United States)

    He, Hong-Jian; Zhang, Zhen

    2017-08-01

    We show that gravitational lensing can provide a direct method to probe the nature of dark energy at astrophysical scales. For lensing system as an isolated astrophysical object, we derive the dark energy contribution to gravitational potential as a repulsive power-law term, containing a generic equation of state parameter w. We find that it generates w-dependent and position-dependent modification to the conventional light orbital equation of w=‑1. With post-Newtonian approximation, we compute its direct effect for an isolated lensing system at astrophysical scales and find that the dark energy force can deflect the path of incident light rays. We demonstrate that the dark-energy-induced deflection angle ΔαDEpropto M(1+1/3w) (with 1+1/3w > 0), which increases with the lensing mass M and consistently approaches zero in the limit M→ 0. This effect is distinctive because dark energy tends to diffuse the rays and generates concave lensing effect. This is in contrast to the conventional convex lensing effect caused by both visible and dark matter. Measuring such concave lensing effect can directly probe the existence and nature of dark energy. We estimate this effect and show that the current gravitational lensing experiments are sensitive to the direct probe of dark energy at astrophysical scales. For the special case w=‑1, our independent study favors the previous works that the cosmological constant can affect light bending, but our prediction qualitatively and quantitatively differ from the literature, including our consistent realization of ΔαDE → 0 (under 0M→ ) at the leading order.

  3. Feedback control of optical beam spatial profiles using thermal lensing

    CERN Document Server

    Liu, Zhanwei; Arain, Muzammil A; Williams, Luke; Mueller, Guido; Tanner, David B; Reitze, David H

    2013-01-01

    A method for active control of the spatial profile of a laser beam using adaptive thermal lensing is described. A segmented electrical heater was used to generate thermal gradients across a transmissive optical element, resulting in a controllable thermal lens. The segmented heater also allows the generation of cylindrical lenses, and provides the capability to steer the beam in both horizontal and vertical planes. Using this device as an actuator, a feedback control loop was developed to stabilize the beam size and position.

  4. Novel Antennas Based Upon Extraordinary Transmission Metamaterial Lenses

    Science.gov (United States)

    2011-08-01

    similarities and differences; a full band characterization of the focal chromatic aberration of both plano-concave and bi- concave lens, instead of...0.5 Frequency (GHz) βz·dz/2π dispersion in the structure which limits its bandwidth and causes chromatic aberration as TE-lenses do. The index of...bandwidth and chromatic aberration usual metallic lenses may have better performance. A more thorough analysis would include the dependence of n on the

  5. Polymer Compund Refractive Lenses for Hard X-ray Nanofocusing

    OpenAIRE

    Krywka, Christina; Last, Arndt; Marschall, Felix; Markus, Otto; Georgi, Sebastian; Mueller, Martin; Mohr, Jürgen

    2016-01-01

    Compound refractive lenses fabricated out of SU-8 negative photoresist have been used to generate a nanofocused, i.e. sub-μm sized X-ray focal spot at an X-ray nanodiffraction setup. X-ray microscopy and X-ray diffraction techniques have conceptually different demands on nanofocusing optical elements and so with the application of X-ray nanodiffraction in mind, this paper presents the results of an initial characterization of polymer lenses used as primary focusin...

  6. Hubble Constant, Lensing, and Time Delay in Relativistic MOND

    OpenAIRE

    2012-01-01

    Time delay in galaxy gravitational lensing systems has been used to determine the value of Hubble constant. As in other dynamical phenomena at the scale of galaxy, dark matter is often invoked in gravitational lensing to account for the "missing mass" (the apparent discrepancy between the dynamical mass and the luminous mass). Alternatively, modified gravity can be used to explain the discrepancy. In this paper we adopt the Tensor-Vector-Scalar gravity (TeVeS), a relativistic version of MOdif...

  7. What is Gravitational Lensing? (LBNL Summer Lecture Series)

    Energy Technology Data Exchange (ETDEWEB)

    Leauthaud, Alexie; Nakajima, Reiko [Berkeley Center for Cosmological Physics

    2009-07-28

    Summer Lecture Series 2009: Gravitational lensing is explained by Einstein's general theory of relativity: galaxies and clusters of galaxies, which are very massive objects, act on spacetime by causing it to become curved. Alexie Leauthaud and Reiko Nakajima, astrophysicists with the Berkeley Center for Cosmological Physics, will discuss how scientists use gravitational lensing to investigate the nature of dark energy and dark matter in the universe.

  8. Direct Shear Mapping - a new weak lensing tool

    CERN Document Server

    de Burgh-Day, Catherine O; Webster, Rachel L; Hopkins, Andrew M

    2015-01-01

    We have developed a new technique called Direct Shear Mapping (DSM) to measure gravitational lensing shear directly from observations of a single background source. The technique assumes the velocity map of an un-lensed, stably-rotating galaxy will be rotationally symmetric. Lensing distorts the velocity map making it asymmetric. The degree of lensing can be inferred by determining the transformation required to restore axisymmetry. This technique is in contrast to traditional weak lensing methods, which require averaging an ensemble of background galaxy ellipticity measurements, to obtain a single shear measurement. We have tested the efficacy of our fitting algorithm with a suite of systematic tests on simulated data. We demonstrate that we are in principle able to measure shears as small as 0.01. In practice, we have fitted for the shear in very low redshift (and hence un-lensed) velocity maps, and have obtained null result with an error of $\\pm 0.01$. This high sensitivity results from analysing spatially...

  9. MUSE observations of the lensing cluster Abell 1689

    CERN Document Server

    Bina, D; Richard, J; Lewis, J; Patrício, V; Cantalupo, S; Herenz, E C; Soto, K; Weilbacher, P; Bacon, R; Vernet, J D R; Wisotzki, L; Clément, B; Cuby, J G; Lagattuta, D J; Soucail, G; Verhamme, A

    2016-01-01

    We present the results obtained with MUSE on the core of the lensing cluster A1689. Integral-field observations with MUSE provide a unique view of the central region, allowing us to conduct a complete census on both cluster galaxies and lensed background sources, identified based on their spectral features without preselection. We investigate the multiple-image configuration for all known sources in the field. Previous to our survey, 28 different lensed galaxies displaying 46 multiple images were known in the MUSE field of view, most of them based on photometric redshifts and lensing considerations. Among them, we spectroscopically confirm 12 images based on their emission-lines, corresponding to 7 different lensed galaxies between z = 0.95 and 5.0. In addition, 14 new galaxies have been spectroscopically identified in this area, with redshifts ranging between 0.8 and 6.2. All background sources within the MUSE field of view correspond to multiple-imaged systems lensed by A1689. 17 sources in total are found ...

  10. Weak gravitational lensing with the Hyper Suprime-Cam survey

    Science.gov (United States)

    Mandelbaum, Rachel; Hyper Suprime-Cam (HSC) Collaboration

    2017-01-01

    Data from the Hyper Suprime-Cam (HSC) survey on the Subaru telescope show great promise for weak gravitational lensing science. The unprecedented combination of area, depth, and imaging quality of this survey (with median i-band seeing of 0.6 arcsec) will enable a wide array of weak lensing measurements, with significant contributions from lenses up to redshift z~1. Applications include cosmological weak lensing measurements from shear-shear and galaxy-shear correlations, which will be especially powerful when combined with the overlapping SDSS-III spectroscopic datasets; and studies of the dark matter halos of galaxies and galaxy clusters. In this talk, I will demonstrate the imaging quality and the tests used to validate the weak lensing measurements. These include null tests internal to the data, comparisons with external datasets, and image simulation-based tests. I will also show the lensing mass profiles of spectroscopic galaxies from the SDSS-III, illustrating the current signal-to-noise ratio on small and large scales and demonstrating the potential for innovative galaxy and cosmological science with the complete survey area.

  11. Cosmological constraints from weak lensing non-Gaussian statistics

    Science.gov (United States)

    Liu, Jia; Haiman, Zoltan; Petri, Andrea; Hill, James; Hui, Lam; Kratochvil, Jan Michael; May, Morgan

    2016-01-01

    Weak gravitational lensing is one of the most promising techniques to probe dark energy. Our work to date suggests that the information in the nonlinear regime exceeds that in the two-point functions. Using the publicly available data from the 154 deg^2 CFHTLenS survey and a large suite of ray-tracing N-body simulations on a grid of 91 cosmological models, we find that constraints from peak counts are comparable to those from the power spectrum, and somewhat tighter when different smoothing scales are combined.I will also introduce the utility of cross-correlating weak galaxy lensing maps with CMB lensing maps, a technique that will be useful to probe structures at an intermediate redshift of 0.9, as larger weak lensing surveys such as HSC, DES, KiDS, Euclid, and LSST come online. We cross-correlate the CFHTLenS galaxy lensing convergence maps with Planck CMB lensing maps. Our results show two sigma tension with the constraints obtained from the Planck temperature measurements. I will discuss possible sources of the tension, including intrinsic alignments, photo-z uncertainties, masking of tSZ in the CMB maps, and the multiplicative bias.

  12. On Autobiographical Lenses: from Perspective to Performance

    Directory of Open Access Journals (Sweden)

    Nilly R. Harag

    2013-05-01

    Full Text Available  A lens is an instrument one looks through to bring new perspectives into focus, enabling the transformation of experience from a magnified self-concentrated space to a wide horizon.In A Portrait of the Artist as A Young Man, Joyce posits autopsia, or “seeing for oneself,” as the only mode of knowledge, rather than a blind acceptance of traditions, beliefs and social norms. Joyce’s myopic observer-protagonist is marked by a Cartesian self-reflexiveness and by a modernist self-conscious creation of self. The structure of the self, its house of being, is created in A Portrait mainly through the epiphanic gaze. Epiphanies may be regarded as the building blocks of self and narrative; they comprehend an architectural configuration of vision. It is in the visionary moment that the kaleidoscope of the self crystallizes. The fictional prospect of the novel is made up of multiple viewpoints; the protagonist, moving in the space of the text, is affected by the presence of these manifold perspectives: the space or magnetic field of A Portrait is charged by epiphanies. In the studio we taught autobiographical lenses were introduced as surgical tools of imagining and creating focal spaces. The paper will be divided into three sections, according to the genealogy of the studio. In the first one we will unfold the point of departure: self -photographed images and autobiographical texts as the source of architectural praxis. The second section will address the alchemical process whereby personal is transformed into public. In the last section we analyze the metaphorical intervention on-site along the periphery of the Old City walls. The loaded location demanded from each student to grapple with the challenge posed by a shared physical territory as the site of conflict. Finally, we cast a retrospective glance at our teaching experience. [In the menu on the right, ARTICLE TOOLS, in "Supplementary Files" link you can download the .pdf presentations of

  13. IRAC Snapshot Imaging of Massive-Cluster Gravitational Lenses Observed by the Herschel Lensing Survey

    Science.gov (United States)

    Egami, Eiichi; Rawle, Timothy; Cava, Antonio; Clement, Benjamin; Dessauges-Zavadsky, Miroslava; Ebeling, Harald; Kneib, Jean-Paul; Perez-Gonzalez, Pablo; Richard, Johan; Rujopakarn, Wiphu; Schaerer, Daniel; Walth, Gregory

    2015-10-01

    Using the Herschel Space Observatory, our team has been conducting a large survey of the fields of massive galaxy clusters, 'The Herschel Lensing Survey (HLS)' (PI: Egami; 419 hours). The main scientific goal is to penetrate the confusion limit of Herschel by taking advantage of the strong gravitational lensing power of these massive clusters and study the population of low-luminosity and/or high-redshift dusty star-forming galaxies that are beyond the reach of field Herschel surveys. In the course of this survey, we have obtained deep PACS (100/160 um) and SPIRE (250/350/500 um) images for 54 clusters (HLS-deep) as well as shallower (but nearly confusion-limited) SPIRE images for 527 clusters (HLS-snapshot). The goal of this proposal is to obtain shallow (500 sec/band) 3.6/4.5 um images of 266 cluster fields that have been observed by the HLS-snapshot survey but do not have any corresponding IRAC data. The HLS-snapshot SPIRE images are deep enough to detect a large number of sources in the target cluster fields, many of which are distant star-forming galaxies lensed by the foreground clusters, and the large sample size of HLS-snapshot promises a great potential for making exciting discoveries. Yet, these Herschel images would be of limited use if we could not identify the counterparts of the Herschel sources accurately and efficiently. The proposed IRAC snapshot program will greatly enhance the utility of these Herschel data, and will feed powerful gound observing facilities like ALMA and NOEMA with interesting targets to follow up.

  14. Spitzer/IRAC Imaging of Exceptionally Bright Cluster-Lensed Submillimeter Galaxies Discovered by the Herschel Lensing Survey

    Science.gov (United States)

    Egami, Eiichi; Ebeling, Harald; Rawle, Timothy; Clement, Benjamin; Walth, Gregory; Pereira, Maria; Richard, Johan; Kneib, Jean-Paul

    2012-12-01

    Over the last few years, discoveries of exceptionally bright (e.g., observed S_peak > 100 mJy in the Herschel/SPIRE bands) gravitationally lensed submillimeter galaxies (SMGs) have generated great excitement. This is because these gravitationally lensed SMGs are so bright that they enable us to perform a variety of follow-up observations using a suite of observing facilities in the submillimeter, millimeter, and radio now available on the ground. Using Herschel, our team has been conducting a survey of such bright lensed galaxies in the fields of massive galaxy clusters: ``The Herschel Lensing Survey (HLS)'' (PI: Egami; 419 hours). This large Herschel program targets a total of 581 X-ray/SZ-selected massive clusters, and is currently 80% complete. Cluster lenses are often more powerful than galaxy lenses, producing larger magnifications. For example, typical magnification factors for galaxy-lensed Herschel sources are x10 or less while cluster-lensed systems can often produce magnification factors of x20-30 and even above x100. Cluster lenses will therefore allow us to detect and study intrinsically less-luminous and/or more distant sources with the ability to provide a view of finer-scale (i.e., sub-kpc) structures. Here, we propose to conduct Spitzer/IRAC imaging of 56 bright lensed SMG candidates we have identified in the ~470 HLS cluster fields observed so far. The main scientific goal is twofold: (1) to locate the underlying stellar component, and (2) to study its properties (e.g., stellar mass, specific star-formation rate) by constraining the rest-frame near-infrared SED and comparing with the Herschel and other submillimeter/millimeter data (e.g., SMA, PdB, ALMA, etc.). These rare bright lensed SMGs will allow us to probe the population of heavily dust-obscured vigorously star-forming galaxies at high redshift (z>1), which is thought to play an important role in the cosmic star-formation history of the Universe and yet has been difficult to study due to the

  15. Informative document waste plastics

    NARCIS (Netherlands)

    Nagelhout D; Sein AA; Duvoort GL

    1989-01-01

    This "Informative document waste plastics" forms part of a series of "informative documents waste materials". These documents are conducted by RIVM on the indstruction of the Directorate General for the Environment, Waste Materials Directorate, in behalf of the program of

  16. A Plastic Menagerie

    Science.gov (United States)

    Hadley, Mary Jane

    2010-01-01

    Bobble heads had become quite popular, depicting all sorts of sports figures, animals, and even presidents. In this article, the author describes how her fourth graders made bobble head sculptures out of empty plastic drink bottles. (Contains 1 online resource.)

  17. Cortical plasticity and rehabilitation.

    Science.gov (United States)

    Moucha, Raluca; Kilgard, Michael P

    2006-01-01

    The brain is constantly adapting to environmental and endogenous changes (including injury) that occur at every stage of life. The mechanisms that regulate neural plasticity have been refined over millions of years. Motivation and sensory experience directly shape the rewiring that makes learning and neurological recovery possible. Guiding neural reorganization in a manner that facilitates recovery of function is a primary goal of neurological rehabilitation. As the rules that govern neural plasticity become better understood, it will be possible to manipulate the sensory and motor experience of patients to induce specific forms of plasticity. This review summarizes our current knowledge regarding factors that regulate cortical plasticity, illustrates specific forms of reorganization induced by control of each factor, and suggests how to exploit these factors for clinical benefit.

  18. Mechanical plasticity of cells

    Science.gov (United States)

    Bonakdar, Navid; Gerum, Richard; Kuhn, Michael; Spörrer, Marina; Lippert, Anna; Schneider, Werner; Aifantis, Katerina E.; Fabry, Ben

    2016-10-01

    Under mechanical loading, most living cells show a viscoelastic deformation that follows a power law in time. After removal of the mechanical load, the cell shape recovers only incompletely to its original undeformed configuration. Here, we show that incomplete shape recovery is due to an additive plastic deformation that displays the same power-law dynamics as the fully reversible viscoelastic deformation response. Moreover, the plastic deformation is a constant fraction of the total cell deformation and originates from bond ruptures within the cytoskeleton. A simple extension of the prevailing viscoelastic power-law response theory with a plastic element correctly predicts the cell behaviour under cyclic loading. Our findings show that plastic energy dissipation during cell deformation is tightly linked to elastic cytoskeletal stresses, which suggests the existence of an adaptive mechanism that protects the cell against mechanical damage.

  19. Targeting tumour Cell Plasticity

    Institute of Scientific and Technical Information of China (English)

    Elizabeth D. WILLIAMS

    2009-01-01

    @@ Her research is focused on understanding the mechanisms of tumour progression and metastasis, particularly in uro-logical carcinomas (bladder and prostate). Tumour cell plasticity, including epithelial-mesenchymal transition, is a cen-tral theme in Dr Williams' work.

  20. Laser cutting plastic materials

    Energy Technology Data Exchange (ETDEWEB)

    Van Cleave, R.A.

    1980-08-01

    A 1000-watt CO/sub 2/ laser has been demonstrated as a reliable production machine tool for cutting of plastics, high strength reinforced composites, and other nonmetals. More than 40 different plastics have been laser cut, and the results are tabulated. Applications for laser cutting described include fiberglass-reinforced laminates, Kevlar/epoxy composites, fiberglass-reinforced phenolics, nylon/epoxy laminates, ceramics, and disposable tooling made from acrylic.