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Sample records for indirect binocular ophthalmoscopy

  1. Screening for retinopathy of prematurity-a comparison between binocular indirect ophthalmoscopy and RetCam 120

    Shah Parag

    2006-01-01

    Full Text Available Aim: To compare the photographic screening for retinopathy of prematurity (ROP using RetCam 120 with binocular indirect ophthalmoscope (BIO, which is the current gold standard. Setting and Design: Prospective, comparative study. Materials and Methods: A total of 87 RetCam examinations were performed on 27 premature babies. They were stored in a separate file after deleting the identifying information. At the same visit using the BIO with scleral depression, an experienced vitreoretinal surgeon evaluated the fundus in detail. A masked examiner then evaluated the RetCam photographs for presence or absence of ROP, the stage and zone of the disease, and the presence or absence of plus disease. These data were then compared with the BIO findings to determine the sensitivity, specificity, and the positive and negative predictive values of the method. Results: ROP was detected in 63 of 87 examinations by BIO and in 56 of 87 RetCam examinations. Nine RetCam examinations were false-negative and two were false-positive. Sensitivity of RetCam was 85.71% (54/63 and specificity was 91.66% (22/24. The positive and negative predictive values were 96.43% and 70.97% respectively. Conclusion: Nine cases having ROP were missed by the RetCam. All these cases were either in zone 3 or the outer part of zone 2, which later regressed. These were missed mostly because of the restricted mobility of the camera head caused by its size and the barrier caused by the lid speculum arms. No case of threshold ROP was missed. RetCam may replace BIO for screening of ROP.

  2. Smartphone Image Acquisition During Postmortem Monocular Indirect Ophthalmoscopy.

    Lantz, Patrick E; Schoppe, Candace H; Thibault, Kirk L; Porter, William T

    2016-01-01

    The medical usefulness of smartphones continues to evolve as third-party applications exploit and expand on the smartphones' interface and capabilities. This technical report describes smartphone still-image capture techniques and video-sequence recording capabilities during postmortem monocular indirect ophthalmoscopy. Using these devices and techniques, practitioners can create photographic documentation of fundal findings, clinically and at autopsy, without the expense of a retinal camera. Smartphone image acquisition of fundal abnormalities can promote ophthalmological telemedicine--especially in regions or countries with limited resources--and facilitate prompt, accurate, and unbiased documentation of retinal hemorrhages in infants and young children. © 2015 American Academy of Forensic Sciences.

  3. Pain and stress assessment after retinopathy of prematurity screening examination: Indirect ophthalmoscopy versus digital retinal imaging

    Moral-Pumarega M

    2012-08-01

    Full Text Available Abstract Background Increasingly, neonatal clinics seek to minimize painful experiences and stress for premature infants. Fundoscopy performed with a binocular indirect ophthalmoscope is the reference examination technique for screening of retinopathy of prematurity (ROP, and it is associated with pain and stress. Wide-field digital retinal imaging is a recent technique that should be evaluated for minimizing infant pain and stress. Methods The purpose of the study was to assess and compare the impact of using a binocular indirect ophthalmoscope (BIO, or wide-field digital retinal imaging (WFDRI on pain and stress in infants undergoing ROP screening examination. This was a comparative evaluation study of two screening procedures. Ophthalmologic examinations (N = 70 were performed on 24 infants with both BIO and WFDRI. Pain assessments were performed with two specific neonatal scales (Crying, requires oxygen, increased vital signs, expression and sleeplessness, CRIES and, Premature infant pain profile, PIPP just prior to the examination, and 30 seconds, 1 hour, and 24 hours later after ending the examination. Results Changes over time were significantly different between BIO and WFDRI with both scales (PIPP score, p = .007, and CRIES score, p = .001. Median PIPP score (interquartile interval at baseline was 4 (3–5. At 30 seconds the score was 8 (6–9 for BIO and 6 (5–7 for WFDRI, respectively. The increase in PIPP score between baseline and 30 seconds was significantly lower with WFDRI (p = .006. The median increase in CRIES score from baseline to 30 seconds was 1 point lower for WFDRI than for BIO (p  Conclusions A transient short-term pain and stress response occurs with both BIO and WFDRI. Infants examined for screening of ROP with digital retinal imaging present less pain and stress at 30 seconds following completion of the exam when compared with binocular indirect ophthalmoscopy.

  4. Comparison of digital imaging screening and indirect ophthalmoscopy for retinopathy of prematurity.

    Ezz El Din, Zahraa Mohamed; El Sada, Mohamed Ahmed; Ali, Aliaa Adel; Al Husseiny, Khalid; Yousef, Aly Abdel Rahman

    2015-01-01

    The aims of this study were to determine the incidence and severity of retinopathy of prematurity (ROP) using digital imaging screening, confirm findings by indirect opthalmoscopy, and document risk factors of ROP in the neonatal intensive care unit (NICU) of a large tertiary hospital in a developing country. This prospective cohort study included infants with gestational age (GA) ≤ 32 wk, birth weight (BW) ≤ 1,500 g, or older and heavier neonates who were critically ill. Two hundred twenty two eyes (111 infants) were screened with digital imaging (Ret-Cam) and indirect ophthalmoscopy until retinal vascularization was complete or the disease regressed. Perinatal risk factors for ROP were analyzed. The overall incidence of ROP was 18.9 %. The incidence of ROP requiring treatment was 5.4 % (12/222) of the total eyes screened. Lower GA and blood transfusion were independent risk factors associated with ROP by multivariate analysis (p = 0.001, OR = 0.562, 95 % CI = 0.395-0.802, and p = 0.027, OR = 6.11, 95 % CI = 1.22-30.44, respectively). Digital imaging facilitated timely screening and detection of ROP, and enabled transfer of images, allowing early intervention for patients who required treatment.

  5. Simulation models applied to practical learning and skill enhancement in direct and indirect ophthalmoscopy: a review

    Lucas Holderegger Ricci

    2014-10-01

    Full Text Available The purpose of this review was to analyze and describe simulation methods for practical learning and training of the ophthalmoscopy exam and to organize them into specific topics relative to each principle of operation, while evaluating their preliminary results. A critical review of articles that described and evaluated simulated models for ophthalmoscopy published in the last ten years (2004-2014 was performed. One hundred articles about ophthalmology and simulation were found in national and international periodicals, but only a few discussed the examination of the posterior pole of the eye. For this study, 25 articles were considered; those articles described simulation methods, general concepts, and its actual use in ophthalmoscopy. There were many different simulation methods described, but only few articles proved their efficacy or performed a comparison between models. Review of this topic may give information for the critical analysis of the simulation devices and ideas for the development of new ones.

  6. [The efficacy of large spot indirect ophthalmoscopy laser alone or combined with systemic chemotherapy in retinoblastoma therapy].

    Liang, J H; Cheng, Y; Deng, X; Yu, Y Y; Li, X X

    2016-10-11

    Objective: To evaluate the efficacy of large spot indirect ophthalmoscopy laser alone or combined with systemic chemotherapy in the treatment of early and middle stage retinoblastoma. Methods: Retrospective series case study. Clinical data of 21 patients (22 eyes) who were diagnosed as retinoblastoma (RB) in Peking University People's Hospital from March 2009 to August 2014 were collected. Medical and family history, ocular ultrasound, orbital and cranial MRI or CT examination of RB Children were detailed recorded. Ocular examination and laser treatment were performed under general anesthesia, once every 3-4 weeks until the tumor was under control. The observation period was at least 3 months after the last treatment. The ocular examination included intraocular pressure measurement, anterior segment and fundus examination and the fundus photography with Retcam. Laser therapeutic instrument was large spot indirect ophthalmoscopy laser of 810nm wavelength. Results: Of the 21 children, 16 were male and 5 were female. The range of age was 3 to 82 months averaged 17.3 months. Among 22 eyes, four with small tumor, eight with medium tumor, and ten with large tumor. Two eyes underwent laser treatment only and 20 eyes underwent laser treatment combined with systemic chemotherapy. During the average observation period of 33.9 months, 15 tumors were treated successfully, but 7 failed. The total success rate was 68.2%. The number and success rate of small, medium and large tumor eyes were 4 (100%), 5 (62.5%) and 5 (50%), respectively. There was one case of tumor brain metastases, and the classification of contralateral eye of the child was E phase. Iris burns happened in one eye, obvious vitreous proliferation in one eye and mild vitreous hemorrhage occurred in two eyes, which did not affect the treatment of laser. However, obvious tumor hemorrhage happened in two eyes and affected laser therapy. There was no complicated cataract, iatrogenic retinal hole and tumor intravitreal

  7. Utility of large spot binocular indirect laser delivery for peripheral photocoagulation therapy in children.

    Balasubramaniam, Saranya C; Mohney, Brian G; Bang, Genie M; Link, Thomas P; Pulido, Jose S

    2012-09-01

    The purpose of this article is to demonstrate the utility of the large spot size (LSS) setting using a binocular laser indirect delivery system for peripheral ablation in children. One patient with bilateral retinopathy of prematurity received photocoagulation with standard spot size burns placed adjacently to LSS burns. Using a pixel analysis program called Image J on the Retcam picture, the areas of each retinal spot size were determined in units of pixels, giving a standard spot range of 805 to 1294 pixels and LSS range of 1699 to 2311 pixels. Additionally, fluence was calculated using theoretical retinal areas produced by each spot size: the standard spot setting was 462 mJ/mm2 and the LSS setting was 104 mJ/mm2. For eyes with retinopathy of prematurity, our study shows that LSS laser indirect delivery halves the number of spots required for treatment and reduces fluence by almost one-quarter, producing more uniform spots.

  8. Binocular astronomy

    Tonkin, Stephen

    2014-01-01

    Binoculars have, for many, long been regarded as an “entry level” observational tool, and relatively few have used them as a serious observing instrument. This is changing! Many people appreciate the relative comfort of two-eyed observing, but those who use binoculars come to realize that they offer more than comfort. The view of the stars is more aesthetically pleasing and therefore binocular observers tend to observe more frequently and for longer periods. Binocular Astronomy, 2nd Edition, extends its coverage of small and medium binoculars to large and giant (i.e., up to 300mm aperture) binoculars and also binoviewers, which brings the work into the realm of serious observing instruments. Additionally, it goes far deeper into the varying optical characteristics of binoculars, giving newcomers and advanced astronomers the information needed to make informed choices on purchasing a pair. It also covers relevant aspects of the physiology of binocular (as in “both eyes”) observation. The first edition ...

  9. Binocular combination in abnormal binocular vision.

    Ding, Jian; Klein, Stanley A; Levi, Dennis M

    2013-02-08

    We investigated suprathreshold binocular combination in humans with abnormal binocular visual experience early in life. In the first experiment we presented the two eyes with equal but opposite phase shifted sine waves and measured the perceived phase of the cyclopean sine wave. Normal observers have balanced vision between the two eyes when the two eyes' images have equal contrast (i.e., both eyes contribute equally to the perceived image and perceived phase = 0°). However, in observers with strabismus and/or amblyopia, balanced vision requires a higher contrast image in the nondominant eye (NDE) than the dominant eye (DE). This asymmetry between the two eyes is larger than predicted from the contrast sensitivities or monocular perceived contrast of the two eyes and is dependent on contrast and spatial frequency: more asymmetric with higher contrast and/or spatial frequency. Our results also revealed a surprising NDE-to-DE enhancement in some of our abnormal observers. This enhancement is not evident in normal vision because it is normally masked by interocular suppression. However, in these abnormal observers the NDE-to-DE suppression was weak or absent. In the second experiment, we used the identical stimuli to measure the perceived contrast of a cyclopean grating by matching the binocular combined contrast to a standard contrast presented to the DE. These measures provide strong constraints for model fitting. We found asymmetric interocular interactions in binocular contrast perception, which was dependent on both contrast and spatial frequency in the same way as in phase perception. By introducing asymmetric parameters to the modified Ding-Sperling model including interocular contrast gain enhancement, we succeeded in accounting for both binocular combined phase and contrast simultaneously. Adding binocular contrast gain control to the modified Ding-Sperling model enabled us to predict the results of dichoptic and binocular contrast discrimination experiments

  10. 间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离%Krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles in the treatment of retinal detachment

    郑穗联; 陈如; 王若洁; 蔡剑秋; 施明光

    2011-01-01

    Objective To assess the clinical result of the krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles.Methods Forty-one eyes of 41 patients were treated with encircling scleral buckles and drainage, some combined with intravitreal injection of gas or balanced salt solution (BSS).All of the retinal breaks were treated with krypton laser photocoagulation using indirect ophthalmoscopy after surgery.Results The visual acuity improved (P<0.05).The reattachment of the retina: 36 eyes were successfully repaired, 5 eyes became recurrent retinal detachment (the reattachment rate was 88.37%).Among the 5 cases, 4 patients were successfully treated with vitrectomy except one patient of traumatic retinal detachment was given up.Conclusions The treatment of retinal detachment should follow the principles of simple surgical methods and fewer complications.The krypton laser photocoagulation using indirect ophthalmoscopy combined with improved encircling scleral buckles in the treatment of retinal detachment in proper cases is a safe, simple and convenient, easy operated and effective method.%目的 讨论采用间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离的临床疗效.方法 对41例41只眼PVRB级或以下的孔源性视网膜脱离病人行宽环扎、放液,部分病人联合玻璃体腔注气或平衡液,术后间接镜氪激光治疗视网膜裂孔.结果 视力提高:术后视力为3.87±0.74,术前视力为3.40±0.86,P<0.05.视网膜复位情况:41只眼中手术成功36只眼,5只眼复发性,成功率88.37%.5只眼复发性视网膜脱离,除1例外伤性视网膜脱离放弃手术外,其余患者均行玻璃体手术后复位.结论 对视网膜脱离术我们建议遵循手术方式简单、并发症少的原则.选择适当病例,间接镜氪激光光凝结合改进宽环扎治疗视网膜脱离是一种安全、简便、易操作、效果良好的方法.

  11. Ophthalmoscopy simulation: advances in training and practice for medical students and young ophthalmologists

    Ricci LH

    2017-06-01

    Full Text Available Lucas Holderegger Ricci,1 Caroline Amaral Ferraz2 1Department of Ophthalmology, School of Medicine, Laureate International Universities, São Paulo (SP, Brazil; 2Department of Ophthalmology, Federal University of São Paulo (UNIFESP, São Paulo (SP, Brazil Objective: To describe and appraise the latest simulation models for direct and indirect ophthalmoscopy as a learning tool in the medical field. Methods: The present review was conducted using four national and international databases – PubMed, Scielo, Medline and Cochrane. Initial set of articles was screened based on title and abstracts, followed by full text analysis. It comprises of articles that were published in the past fifteen years (2002–2017.Results: Eighty-three articles concerning simulation models for medical education were found in national and international databases, with only a few describing important aspects of ophthalmoscopy training and current application of simulation in medical education. After secondary analysis, 38 articles were included.Conclusion: Different ophthalmoscopy simulation models have been described, but only very few studies appraise the effectiveness of each individual model. Comparison studies are still required to determine best approaches for medical education and skill enhancement through simulation models, applied to both medical students as well as young ophthalmologists in training. Keywords: direct ophthalmoscopy, indirect ophthalmoscopy, skills, simulator, simulation models

  12. Direct ophthalmoscopy on YouTube

    Borgersen, Nanna Jo; Henriksen, Mikael Johannes Vuokko; Konge, Lars

    2016-01-01

    BACKGROUND: Direct ophthalmoscopy is well-suited for video-based instruction, particularly if the videos enable the student to see what the examiner sees when performing direct ophthalmoscopy. We evaluated the pedagogical effectiveness of instructional YouTube videos on direct ophthalmoscopy...... in general. We then systematically searched YouTube. Two authors reviewed eligible videos to assess eligibility and extract data on video statistics, content, and approach to visualization. Correlations between video statistics and contents were investigated using two-tailed Spearman's correlation. RESULTS...... the patient and how to examine the fundus. Time spent on fundus examination correlated with the number of views per week (Spearman's ρ=0.53; P=0.029). CONCLUSION: Videos may help overcome the pedagogical issues in teaching direct ophthalmoscopy; however, the few available videos on YouTube fail to address...

  13. [Binocular coordination during reading].

    Bassou, L; Granié, M; Pugh, A K; Morucci, J P

    1992-01-01

    Is there an effect on binocular coordination during reading of oculomotor imbalance (heterophoria, strabismus and inadequate convergence) and of functional lateral characteristics (eye preference and perceptually privileged visual laterality)? Recordings of the binocular eye-movements of ten-year-old children show that oculomotor imbalances occur most often among children whose left visual perceptual channel is privileged, and that these subjects can present optomotor dissociation and manifest lack of motor coordination. Close binocular motor coordination is far from being the norm in reading. The faster reader displays saccades of differing spatial amplitude and the slower reader an oculomotor hyperactivity, especially during fixations. The recording of binocular movements in reading appears to be an excellent means of diagnosing difficulties related to visual laterality and to problems associated with oculomotor imbalance.

  14. Improved Binocular Outcomes Following Binocular Treatment for Childhood Amblyopia.

    Kelly, Krista R; Jost, Reed M; Wang, Yi-Zhong; Dao, Lori; Beauchamp, Cynthia L; Leffler, Joel N; Birch, Eileen E

    2018-03-01

    Childhood amblyopia can be treated with binocular games or movies that rebalance contrast between the eyes, which is thought to reduce depth of interocular suppression so the child can experience binocular vision. While visual acuity gains have been reported following binocular treatment, studies rarely report gains in binocular outcomes (i.e., stereoacuity, suppression) in amblyopic children. Here, we evaluated binocular outcomes in children who had received binocular treatment for childhood amblyopia. Data for amblyopic children enrolled in two ongoing studies were pooled. The sample included 41 amblyopic children (6 strabismic, 21 anisometropic, 14 combined; age 4-10 years; ≤4 prism diopters [PD]) who received binocular treatment (20 game, 21 movies; prescribed 9-10 hours treatment). Amblyopic eye visual acuity and binocular outcomes (Randot Preschool Stereoacuity, extent of suppression, and depth of suppression) were assessed at baseline and at 2 weeks. Mean amblyopic eye visual acuity (P suppression (P = 0.003) were reduced from baseline at the 2-week visit (87% game adherence, 100% movie adherence). Depth of suppression was reduced more in children aged suppression was correlated with a larger depth of suppression reduction at 2 weeks (P = 0.001). After 2 weeks, binocular treatment in amblyopic children improved visual acuity and binocular outcomes, reducing the extent and depth of suppression and improving stereoacuity. Binocular treatments that rebalance contrast to overcome suppression are a promising additional option for treating amblyopia.

  15. First Peruvian binoculars

    Baldwin, Guillermo; Gonzales, Franco; Pérez S., Carlos

    2017-11-01

    In Peru, as in almost all Latin America, precision optical industry is almost null. One reason is the scarcity of human and technological resources. But, a few years ago, a masters and diploma university program in optical engineering was started in our university: Pontificia Universidad Católica del Perú1 (PUCP) in Lima. Also, an optical shop on precision optics was implemented. Some students were trained at CIO in Leon, Mexico. In order to motivate optical business startups in Peru we planned to show some possibilities of optical devices fabrication trough doing prototypes. So, we started doing a small reflective telescope for moon observation2, 3, where mirror and ocular polishing and opto-mechanics had priority. Aluminum evaporation was included. Now, we do a new step developing a binocular, as we know, it never was made before in Peru. This work includes the binocular geometric optics and opto-mechanical designs, the ocular manufacturing, and the binocular characterization of an 8x35 binocular for amateur observation.

  16. Amblyopia and binocular vision.

    Birch, Eileen E

    2013-03-01

    Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3%-3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of binocular dysfunction in the genesis of amblyopia and the constellation of visual and motor deficits that accompany the visual acuity deficit has been identified. These findings motivated us to evaluate a new, binocular approach to amblyopia treatment with the goals of reducing or eliminating residual and recurrent amblyopia and of improving the deficient ocular motor function and fine motor skills that accompany amblyopia. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Rebalancing binocular vision in amblyopia.

    Ding, Jian; Levi, Dennis M

    2014-03-01

    Humans with amblyopia have an asymmetry in binocular vision: neural signals from the amblyopic eye are suppressed in the cortex by the fellow eye. The purpose of this study was to develop new models and methods for rebalancing this asymmetric binocular vision by manipulating the contrast and luminance in the two eyes. We measured the perceived phase of a cyclopean sinewave by asking normal and amblyopic observers to indicate the apparent location (phase) of the dark trough in the horizontal cyclopean sine wave relative to a black horizontal reference line, and used the same stimuli to measure perceived contrast by matching the binocular combined contrast to a standard contrast presented to one eye. We varied both the relative contrast and luminance of the two eyes' inputs, in order to rebalance the asymmetric binocular vision. Amblyopic binocular vision becomes more and more asymmetric the higher the stimulus contrast or spatial frequency. Reanalysing our previous data, we found that, at a given spatial frequency, the binocular asymmetry could be described by a log-linear formula with two parameters, one for the maximum asymmetry and one for the rate at which the binocular system becomes asymmetric as the contrast increases. Our new data demonstrates that reducing the dominant eye's mean luminance reduces its suppression of the non-dominant eye, and therefore rebalances the asymmetric binocular vision. While the binocular asymmetry in amblyopic vision can be rebalanced by manipulating the relative contrast or luminance of the two eyes at a given spatial frequency and contrast, it is very difficult or even impossible to rebalance the asymmetry for all visual conditions. Nonetheless, wearing a neutral density filter before the dominant eye (or increasing the mean luminance in the non-dominant eye) may be more beneficial than the traditional method of patching the dominant eye for treating amblyopia. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The

  18. In vivo integrated photoacoustic ophthalmoscopy, optical coherence tomography, and scanning laser ophthalmoscopy for retinal imaging

    Song, Wei; Zhang, Rui; Zhang, Hao F.; Wei, Qing; Cao, Wenwu

    2012-12-01

    The physiological and pathological properties of retina are closely associated with various optical contrasts. Hence, integrating different ophthalmic imaging technologies is more beneficial in both fundamental investigation and clinical diagnosis of several blinding diseases. Recently, photoacoustic ophthalmoscopy (PAOM) was developed for in vivo retinal imaging in small animals, which demonstrated the capability of imaging retinal vascular networks and retinal pigment epithelium (RPE) at high sensitivity. We combined PAOM with traditional imaging modalities, such as fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), and auto-fluorescence scanning laser ophthalmoscopy (AF-SLO), for imaging rats and mice. The multimodal imaging system provided more comprehensive evaluation of the retina based on the complementary imaging contrast mechanisms. The high-quality retinal images show that the integrated ophthalmic imaging system has great potential in the investigation of blinding disorders.

  19. The large binocular telescope.

    Hill, John M

    2010-06-01

    The Large Binocular Telescope (LBT) Observatory is a collaboration among institutions in Arizona, Germany, Italy, Indiana, Minnesota, Ohio, and Virginia. The telescope on Mount Graham in Southeastern Arizona uses two 8.4 m diameter primary mirrors mounted side by side. A unique feature of the LBT is that the light from the two Gregorian telescope sides can be combined to produce phased-array imaging of an extended field. This cophased imaging along with adaptive optics gives the telescope the diffraction-limited resolution of a 22.65 m aperture and a collecting area equivalent to an 11.8 m circular aperture. This paper describes the design, construction, and commissioning of this unique telescope. We report some sample astronomical results with the prime focus cameras. We comment on some of the technical challenges and solutions. The telescope uses two F/15 adaptive secondaries to correct atmospheric turbulence. The first of these adaptive mirrors has completed final system testing in Firenze, Italy, and is planned to be at the telescope by Spring 2010.

  20. Latent binocular function in amblyopia.

    Chadnova, Eva; Reynaud, Alexandre; Clavagnier, Simon; Hess, Robert F

    2017-11-01

    Recently, psychophysical studies have shown that humans with amblyopia do have binocular function that is not normally revealed due to dominant suppressive interactions under normal viewing conditions. Here we use magnetoencephalography (MEG) combined with dichoptic visual stimulation to investigate the underlying binocular function in humans with amblyopia for stimuli that, because of their temporal properties, would be expected to bypass suppressive effects and to reveal any underlying binocular function. We recorded contrast response functions in visual cortical area V1 of amblyopes and normal observers using a steady state visually evoked responses (SSVER) protocol. We used stimuli that were frequency-tagged at 4Hz and 6Hz that allowed identification of the responses from each eye and were of a sufficiently high temporal frequency (>3Hz) to bypass suppression. To characterize binocular function, we compared dichoptic masking between the two eyes in normal and amblyopic participants as well as interocular phase differences in the two groups. We observed that the primary visual cortex responds less to the stimulation of the amblyopic eye compared to the fellow eye. The pattern of interaction in the amblyopic visual system however was not significantly different between the amblyopic and fellow eyes. However, the amblyopic suppressive interactions were lower than those observed in the binocular system of our normal observers. Furthermore, we identified an interocular processing delay of approximately 20ms in our amblyopic group. To conclude, when suppression is greatly reduced, such as the case with our stimulation above 3Hz, the amblyopic visual system exhibits a lack of binocular interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A 3D virtual reality ophthalmoscopy trainer.

    Wilson, Andrew S; O'Connor, Jake; Taylor, Lewis; Carruthers, David

    2017-12-01

    Performing eye examinations is an important clinical skill that medical students often find difficult to become proficient in. This paper describes the development and evaluation of an innovative 3D virtual reality (VR) training application to support learning these skills. The VR ophthalmoscope was developed by a clinical team and technologist using the unity game engine, smartphone and virtual reality headset. It has a series of tasks that include performing systematic eye examinations, identifying common eye pathologies and a knowledge quiz. As part of their clinical training, 15 fourth-year medical students were surveyed for their views on this teaching approach. The Technology Acceptance Model was used to evaluate perceived usefulness and ease of use. Data were also collected on the usability of the app, together with the students' written comments about it. Users agreed that the teaching approach improved their understanding of ophthalmoscopy (n = 14), their ability to identify landmarks in the eye (n = 14) and their ability to recognise abnormalities (n = 15). They found the app easy to use (n = 15), the teaching approach informative (n = 13) and that it would increase students' confidence when performing these tasks in future (n = 15). Performing eye examinations is an important clinical skill DISCUSSION: The evaluation showed that a VR app can successfully simulate the processes involved in performing eye examinations. The app was highly rated for all elements of perceived usefulness, ease of use and usability. Medical students stated that they would like to be taught other medical skills in this way in future. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  2. Human milk for neonatal pain relief during ophthalmoscopy

    Laiane Medeiros Ribeiro

    2013-10-01

    Full Text Available Ophthalmoscopy performed for the early diagnosis of retinopathy of prematurity (ROP is painful for preterm infants, thus necessitating interventions for minimizing pain. The present study aimed to establish the effectiveness of human milk, compared with sucrose, for pain relief in premature infants subjected to ophthalmoscopy for the early diagnosis of ROP. This investigation was a pilot, quasi-experimental study conducted with 14 premature infants admitted to the neonatal intensive care unit (NICU of a university hospital. Comparison between the groups did not yield a statistically significant difference relative to the crying time, salivary cortisol, or heart rate (HR. Human milk appears to be as effective as sucrose in relieving acute pain associated with ophthalmoscopy. The study’s limitations included its small sample size and lack of randomization. Experimental investigations with greater sample power should be performed to reinforce the evidence found in the present study.

  3. Ophthalmoscopy versus non-mydriatic fundus photography in the ...

    The contribution of non-mydriatic fundus photography in the detection of diabetic retinopathy before and after dilatation of the pupils in black diabetics was investigated and compared with direct ophthalmoscopy. Eighty-six patients were examined and good-quality photographs were obtained for 54,7% of eyes before and ...

  4. Photography or Ophthalmoscopy for Detection of Diabetic Retinopathy?

    Leiden, Hendrik A. van; Moll, Annette C.; Dekker, Jacqueline M.; Abramoff, M.D.; Polak, Bettine C.P.

    2003-01-01

    The U.K. National Screening Committee recommended digital fundus photography as the screening method of choice for diabetic retinopathy (DR). However, concerns have been expressed about replacing ophthalmoscopy with slit-lamp biomicroscopy by digital photography. These concerns included the

  5. Colour-grapheme synaesthesia affects binocular vision

    Chris L.E. Paffen

    2011-11-01

    Full Text Available In colour-grapheme synaesthesia, non-coloured graphemes are perceived as being inherently coloured. In recent years, it has become evident that synaesthesia-inducing graphemes can affect visual processing in a manner comparable to real, physical colours. Here, we exploit the phenomenon of binocular rivalry in which incompatible images presented dichoptically compete for conscious expression. Importantly, the competition only arises if the two images are sufficiently different; if the difference between the images is small, the images will fuse into a single mixed percept. We show that achromatic graphemes that induce synaesthetic colour percepts evoke binocular rivalry, while without the synaesthetic percept, they do not. That is, compared to achromatically perceived graphemes, synaesthesia-inducing graphemes increase the predominance of binocular rivalry over binocular fusion. This finding shows that the synaesthetic colour experience can provide the conditions for evoking binocular rivalry, much like stimulus features that induce rivalry in normal vision.

  6. Binocular contrast discrimination needs monocular multiplicative noise

    Ding, Jian; Levi, Dennis M.

    2016-01-01

    The effects of signal and noise on contrast discrimination are difficult to separate because of a singularity in the signal-detection-theory model of two-alternative forced-choice contrast discrimination (Katkov, Tsodyks, & Sagi, 2006). In this article, we show that it is possible to eliminate the singularity by combining that model with a binocular combination model to fit monocular, dichoptic, and binocular contrast discrimination. We performed three experiments using identical stimuli to measure the perceived phase, perceived contrast, and contrast discrimination of a cyclopean sine wave. In the absence of a fixation point, we found a binocular advantage in contrast discrimination both at low contrasts (discrimination mechanisms: a nonlinear contrast transducer and multiplicative noise (MN). A binocular combination model (the DSKL model; Ding, Klein, & Levi, 2013b) was first fitted to both the perceived-phase and the perceived-contrast data sets, then combined with either the nonlinear contrast transducer or the MN mechanism to fit the contrast-discrimination data. We found that the best model combined the DSKL model with early MN. Model simulations showed that, after going through interocular suppression, the uncorrelated noise in the two eyes became anticorrelated, resulting in less binocular noise and therefore a binocular advantage in the discrimination task. Combining a nonlinear contrast transducer or MN with a binocular combination model (DSKL) provides a powerful method for evaluating the two putative contrast-discrimination mechanisms. PMID:26982370

  7. Restoration of binocular vision in amblyopia.

    Hess, R F; Mansouri, B; Thompson, B

    2011-09-01

    To develop a treatment for amblyopia based on re-establishing binocular vision. A novel procedure is outlined for measuring and reducing the extent to which the fixing eye suppresses the fellow amblyopic eye in adults with amblyopia. We hypothesize that suppression renders a structurally binocular system, functionally monocular. We demonstrate that strabismic amblyopes can combine information normally between their eyes under viewing conditions where suppression is reduced by presenting stimuli of different contrast to each eye. Furthermore we show that prolonged periods of binocular combination leads to a strengthening of binocular vision in strabismic amblyopes and eventual combination of binocular information under natural viewing conditions (stimuli of the same contrast in each eye). Concomitant improvement in monocular acuity of the amblyopic eye occurs with this reduction in suppression and strengthening of binocular fusion. Additionally, stereoscopic function was established in the majority of patients tested. We have implemented this approach on a headmounted device as well as on a handheld iPod. This provides the basis for a new treatment of amblyopia, one that is purely binocular and aimed at reducing suppression as a first step.

  8. Binocular Combination of Second-Order Stimuli

    Zhou, Jiawei; Liu, Rong; Zhou, Yifeng; Hess, Robert F.

    2014-01-01

    Phase information is a fundamental aspect of visual stimuli. However, the nature of the binocular combination of stimuli defined by modulations in contrast, so-called second-order stimuli, is presently not clear. To address this issue, we measured binocular combination for first- (luminance modulated) and second-order (contrast modulated) stimuli using a binocular phase combination paradigm in seven normal adults. We found that the binocular perceived phase of second-order gratings depends on the interocular signal ratio as has been previously shown for their first order counterparts; the interocular signal ratios when the two eyes were balanced was close to 1 in both first- and second-order phase combinations. However, second-order combination is more linear than previously found for first-order combination. Furthermore, binocular combination of second-order stimuli was similar regardless of whether the carriers in the two eyes were correlated, anti-correlated, or uncorrelated. This suggests that, in normal adults, the binocular phase combination of second-order stimuli occurs after the monocular extracting of the second-order modulations. The sensory balance associated with this second-order combination can be obtained from binocular phase combination measurements. PMID:24404180

  9. Binocular rivalry produced by temporal frequency differences

    David eAlais

    2012-07-01

    Full Text Available Binocular rivalry occurs when each eye views images that are markedly different. Rather than seeing a binocular fusion of the two, each image is seen exclusively in a stochastic alternation of the monocular images. Here we examine whether temporal frequency differences will trigger binocular rivalry by presenting two random dot arrays that are spatially matched but which modulate temporally at two different rates and contained no net translation. We found that a perceptual alternation between the two temporal frequencies did indeed occur, provided the frequencies were sufficiently different, indicating that temporal information can produce binocular rivalry in the absence of spatial conflict. This finding is discussed with regard to the dependence of rivalry on conflict between spatial and temporal channels.

  10. Does partial occlusion promote normal binocular function?

    Li, Jingrong; Thompson, Benjamin; Ding, Zhaofeng; Chan, Lily Y L; Chen, Xiang; Yu, Minbin; Deng, Daming; Hess, Robert F

    2012-10-03

    There is growing evidence that abnormal binocular interactions play a key role in the amblyopia syndrome and represent a viable target for treatment interventions. In this context the use of partial occlusion using optical devices such as Bangerter filters as an alternative to complete occlusion is of particular interest. The aims of this study were to understand why Bangerter filters do not result in improved binocular outcomes compared to complete occlusion, and to compare the effects of Bangerter filters, optical blur and neutral density (ND) filters on normal binocular function. The effects of four strengths of Bangerter filters (0.8, 0.6, 0.4, 0.2) on letter and vernier acuity, contrast sensitivity, stereoacuity, and interocular suppression were measured in 21 observers with normal vision. In a subset of 14 observers, the partial occlusion effects of Bangerter filters, ND filters and plus lenses on stereopsis and interocular suppression were compared. Bangerter filters did not have graded effect on vision and induced significant disruption to binocular function. This disruption was greater than that of monocular defocus but weaker than that of ND filters. The effect of the Bangerter filters on stereopsis was more pronounced than their effect on monocular acuity, and the induced monocular acuity deficits did not predict the induced deficits in stereopsis. Bangerter filters appear to be particularly disruptive to binocular function. Other interventions, such as optical defocus and those employing computer generated dichoptic stimulus presentation, may be more appropriate than partial occlusion for targeting binocular function during amblyopia treatment.

  11. Measurement of suprathreshold binocular interactions in amblyopia.

    Mansouri, B; Thompson, B; Hess, R F

    2008-12-01

    It has been established that in amblyopia, information from the amblyopic eye (AME) is not combined with that from the fellow fixing eye (FFE) under conditions of binocular viewing. However, recent evidence suggests that mechanisms that combine information between the eyes are intact in amblyopia. The lack of binocular function is most likely due to the imbalanced inputs from the two eyes under binocular conditions [Baker, D. H., Meese, T. S., Mansouri, B., & Hess, R. F. (2007b). Binocular summation of contrast remains intact in strabismic amblyopia. Investigative Ophthalmology & Visual Science, 48(11), 5332-5338]. We have measured the extent to which the information presented to each eye needs to differ for binocular combination to occur and in doing so we quantify the influence of interocular suppression. We quantify these suppressive effects for suprathreshold processing of global stimuli for both motion and spatial tasks. The results confirm the general importance of these suppressive effects in rendering the structurally binocular visual system of a strabismic amblyope, functionally monocular.

  12. P3-4: Binocular Visual Acuity in Exotropia

    Heekyung Yang

    2012-10-01

    Full Text Available Purpose: To investigate binocular interaction of visual acuity in patients with intermittent exotropia and its relationship with accommodative responses during binocular vision. Methods: Sixty-seven patients with intermittent exotropia of 8 years or older were included. Binocular visual acuity (BVA and monocular visual acuity (MVA were measured in sequence. Accommodative responses of both eyes were measured using the WAM-5500 autorefractor/keratometer (GrandSeiko, Fukuyama, Japan during binocular and monocular viewing conditions at 6 m. Accommodative responses during binocular vision were calculated using the difference between the refractive errors of binocular and monocular vision. Main outcome measures: Binocular interactions of visual acuity were categorized as binocular summation, equivalency, or inhibition. The prevalence of the 3 patterns of binocular interaction was investigated. Accommodative responses were correlated with differences between BVA and better MVA. Results: Most patients (41 patients, 61.2% showed binocular equivalency. Binocular inhibition and summation were noted in 6 (9.0% and 20 (29.9% patients, respectively. Linear regression analysis revealed a significant correlation between binocular interaction and accommodative responses during binocular vision (p < .001. Accommodative responses significantly correlated with the angle of exodeviation at distance (p = .002. Conclusions: In patients with intermittent exotropia, binocular inhibition is associated with increased accommodation and a larger angle of exodeviation, suggesting that accommodative convergence is a mechanism that maintains ocular alignment. Thus, BVA inhibition may be attributed to diminishing fusional control in patients with intermittent exotropia.

  13. [Binocular fusion method for prevention of myopia].

    Xu, G D

    1989-03-01

    When looking at a far object with two eyes, relaxation of convergence and accommodation occurred and accompanied by binocular fusion. Using this phenomenon a method of binocular fusion of targets was designed, that is the distance between two targets are just the same as the distance between two visual lines, while looking at a far object. During the images of the targets are fused, the accommodation and convergence are relaxed concomitantly; thus a result of correction of pseudomyopia and prevention of myopia is achieved. By means of binocular fusion, the eye muscle exercises were conducted and resulted in not only the far point further but also the near point closer. The skiascopic examination carried out at the same time of binocular fusion showed that the degrees of relaxed accommodation was 97.9% that of looking at an object in far distance. The above results indicated that the binocular fusion method had excellent effect on the prevention of myopia. This method is simple and feasible, conforms to the visual physiology, and thus can be widely adopted.

  14. Emotion and Interhemispheric Interactions in Binocular Rivalry

    K L Ritchie

    2013-10-01

    Full Text Available Previous research has shown that fear-related stimuli presented in peripheral vision are preferentially processed over stimuli depicting other emotions. Furthermore, emotional content can influence dominance duration in binocular rivalry, with the period of dominance for an emotional image (e.g. a fearful face being significantly longer than a neutral image (e.g. a neutral face or a house. Experiment 1 of the current study combined these two ideas to investigate the role of emotion in binocular rivalry with face/house pairs viewed in the periphery. The results showed that faces were perceived as more dominant than houses, and fearful faces more so than neutral faces, even when viewed in the periphery. Experiment 2 extended this paradigm to present a rival pair in the periphery in each hemifield, with each eye either viewing the same stimulus in each location (traditional condition, or a different stimulus in each location (Diaz-Caneja condition. The results showed that the two pairs tended to rival in synchrony only in the traditional condition. Taken together, the results show that face dominance and emotion dominance in binocular rivalry persist in the periphery, and that interhemispheric interactions in binocular rivalry depend on an eye- as opposed to an object-based mechanism.

  15. Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update

    Zhang, Bing; Li, Ni; Kang, Jie; He, Yi; Chen, Xiao-Ming

    2017-01-01

    Adaptive optics scanning laser ophthalmoscopy (AO-SLO) has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics (AO) and AO-SLO. Then it compares AO-SLO with conventional imaging methods (fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography) and other AO techniques (adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherenc...

  16. Naturalistic depth perception and binocular vision

    Maiello, G.

    2017-01-01

    Humans continuously move both their eyes to redirect their foveae to objects at new depths. To correctly execute these complex combinations of saccades, vergence eye movements and accommodation changes, the visual system makes use of multiple sources of depth information, including binocular disparity and defocus. Furthermore, during development, both fine-tuning of oculomotor control as well as correct eye growth are likely driven by complex interactions between eye movements, accommodation,...

  17. [Binocular functions in amblyopia and strabismus].

    Awaya, S; Sato, M; Tsuzuki, K; Takara, T; Hiraiwa, S; Ota, K; Arai, M; Yoshida, M; Miyake, Y; Terasaki, H; Horiguchi, M; Hirano, K; Hirose, H; Uno, Y; Suzuki, Y; Iwata, M; Takai, Y; Maeda, M; Hisano, S; Kawakita, T; Omura, T; Ota, Y; Kondo, N; Takashi, A; Kawakami, O

    1997-12-01

    Regarding the changing trends in the concept, definition, etiological classification, and criteria for diagnosis of amblyopia, we reviewed a total of 4,693 cases of amblyopia seen during the past 37 years. The amblyopia was divided into four types: strabismic, anisometropic, ametropic, and form vision deprivative. There was a definite trend for the incidence to decrease and for the diagnosis to be made during earlier age in recent years. Although favorable recovery of visual acuity is obtained after treatment of amblyopia and strabismus, there are difficulties in obtaining good binocular functions in early-onset amblyopia and strabismus. This feature was evaluated in regard to motion perception asymmetry (MPA) and binocular depth from motion (DFM). Many cases of early-onset amblyopia and strabismus showed no disparity stereopsis, or position stereopsis, in spite of the presence of DFM. The MPA appeared to be closely related to early-onset esotropia regardless of age, while it disappeared and motion perception became symmetric 4 to 5 months after birth in normal infants. The DFM seemed to play an important role in maintaining good motor alignment for several years after surgery. I developed a checkerboard pattern stimulator in 1978. This method proved to be useful in developing binocular functions and motor alignment by applying simultaneous bifoveolar stimulation and anti-suppression. Extensive exposure to the stimulation was essential for therapeutic success.

  18. Early Studies of Binocular and Binaural Directions

    Nicholas J. Wade

    2018-03-01

    Full Text Available Understanding how the eyes work together to determine the direction of objects provided the impetus for examining integration of signals from the ears to locate sounds. However, the advantages of having two eyes were recorded long before those for two ears were appreciated. In part, this reflects the marked differences in how we can compare perception with one or two organs. It is easier to close one eye and examine monocular vision than to “close” one ear and study monaural hearing. Moreover, we can move our eyes either in the same or in opposite directions, but humans have no equivalent means of moving the ears in unison. Studies of binocular single vision can be traced back over two thousand years and they were implicitly concerned with visual directions from each eye. The location of any point in visual or auditory space can be described by specifying its direction and distance, from the vantage point of an observer. From the late 18th century experiments indicated that binocular direction involved an eye movement component and experimental studies of binaural direction commenced slightly later. However, these early binocular and binaural experiments were not incorporated into theoretical accounts until almost a century later. The early history of research on visual direction with two eyes is contrasted to that on auditory direction with two ears.

  19. Sub-Airy Confocal Adaptive Optics Scanning Ophthalmoscopy.

    Sredar, Nripun; Fagbemi, Oladipo E; Dubra, Alfredo

    2018-04-01

    To demonstrate the viability of improving transverse image resolution in reflectance scanning adaptive optics ophthalmoscopy using sub-Airy disk confocal detection. The foveal cone mosaic was imaged in five human subjects free of known eye disease using two custom adaptive optics scanning light ophthalmoscopes (AOSLOs) in reflectance with 7.75 and 4.30 mm pupil diameters. Confocal pinholes of 0.5, 0.6, 0.8, and 1.0 Airy disk diameters (ADDs) were used in a retinal conjugate plane before the light detector. Average cone photoreceptor intensity profile width and power spectrum were calculated for the resulting images. Detected energy using a model eye was recorded for each pinhole size. The cone photoreceptor mosaic is better resolved with decreasing confocal pinhole size, with the high spatial frequency content of the images enhanced in both the large- and small-pupil AOSLOs. The average cone intensity profile width was reduced by ∼15% with the use of a 0.5 ADD pinhole when compared to a 1.0 ADD, with an accompanying reduction in signal greater than a factor of four. The use of sub-Airy disk confocal pinhole detection without increasing retinal light exposure results in a substantial improvement in image resolution at the cost of larger than predicted signal reduction. Improvement in transverse resolution using sub-Airy disk confocal detection is a practical and low-cost approach that is applicable to all point- and line-scanning ophthalmoscopes, including optical coherence tomographers.

  20. Cone and Rod Loss in Stargardt Disease Revealed by Adaptive Optics Scanning Light Ophthalmoscopy

    Song, Hongxin; Rossi, Ethan A.; Latchney, Lisa; Bessette, Angela; Stone, Edwin; Hunter, Jennifer J.; Williams, David R.; Chung, Mina

    2015-01-01

    Importance Stargardt disease (STGD1) is characterized by macular atrophy and flecks in the retinal pigment epithelium. The causative ABCA4 gene encodes a protein localizing to photoreceptor outer segments. The pathologic steps by which ABCA4 mutations lead to clinically detectable retinal pigment epithelium changes remain unclear. We investigated early STGD1 using adaptive optics scanning light ophthalmoscopy. Observations Adaptive optics scanning light ophthalmoscopy imaging of 2 brothers with early STGD1 and their unaffected parents was compared with conventional imaging. Cone and rod spacing were increased in both patients (P optics scanning light ophthalmoscopy reveals increased cone and rod spacing in areas that appear normal in conventional images, suggesting that photoreceptor loss precedes clinically detectable retinal pigment epithelial disease in STGD1. PMID:26247787

  1. Symptomatology associated with accommodative and binocular vision anomalies

    Ángel García-Muñoz

    2014-10-01

    Conclusions: There is a wide disparity of symptoms related to accommodative and binocular dysfunctions in the scientific literature, most of which are associated with near vision and binocular dysfunctions. The only psychometrically validated questionnaires that we found (n=3 were related to convergence insufficiency and to visual dysfunctions in general and there no specific questionnaires for other anomalies.

  2. Evaluation of an online peer fundus photograph matching program in teaching direct ophthalmoscopy to medical students.

    Kwok, Jason; Liao, Walter; Baxter, Stephanie

    2017-10-01

    Direct ophthalmoscopy is an important clinical skill that is often poorly performed by medical professionals and students. This is attributable to a declining emphasis on ophthalmology in medical school. We present and evaluate a self-directed approach of teaching ophthalmoscopy to medical students that is suitable for the current medical curriculum. Prospective medical education trial. Ninety-five second-year medical students at Queen's University: 32 in the experimental group and 63 in the control group. The experimental group consisted of medical students who practised ophthalmoscopy with one another using an online peer fundus photograph matching exercise created by the Department of Ophthalmology at Queen's University. To use the program, students first examined a peer with an ophthalmoscope and then selected an online photograph of a fundus corresponding to that of the examinee. The program notifies students if a correct selection is made. To encourage use of the program, students participated in a 2-week ophthalmoscopy competition during their ophthalmology rotation. The control group consisted of students who did not participate in the learning exercise. On assessment at the end of the ophthalmology rotation, the experimental group (n = 32) was more accurate in matching fundus photographs compared with the control group (n = 63) (p = 0.02). Participants were faster at performing ophthalmoscopy at the end of the learning exercise (p peer fundus photographs in a self-directed manner appeared to increase the skill and confidence of medical students in ophthalmoscopy. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  3. Binocular Vision in Chronic Fatigue Syndrome.

    Godts, Daisy; Moorkens, Greta; Mathysen, Danny G P

    2016-01-01

    To compare binocular vision measurements between Chronic Fatigue Syndrome (CFS) patients and healthy controls. Forty-one CFS patients referred by the Reference Centre for Chronic Fatigue Syndrome of the Antwerp University Hospital and forty-one healthy volunteers, matched for age and gender, underwent a complete orthoptic examination. Data of visual acuity, eye position, fusion amplitude, stereopsis, ocular motility, convergence, and accommodation were compared between both groups. Patients with CFS showed highly significant smaller fusion amplitudes (P convergence capacity (P accommodation range (P convergence and accommodation should be routinely examined. CFS patients will benefit from reading glasses either with or without prism correction in an earlier stage compared to their healthy peers. Convergence exercises may be beneficial for CFS patients, despite the fact that they might be very tiring. Further research will be necessary to draw conclusions about the efficacy of treatment, especially regarding convergence exercises. To our knowledge, this is the first prospective study evaluating binocular vision in CFS patients. © 2016 Board of regents of the University of Wisconsin System, American Orthoptic Journal, Volume 66, 2016, ISSN 0065-955X, E-ISSN 1553-4448.

  4. Fisiologia da visão binocular Physiology of binocular vision

    Harley E. A. Bicas

    2004-02-01

    Full Text Available A visão binocular de seres humanos resulta da superposição quase completa dos campos visuais de cada olho, o que suscita discriminação perceptual de localizações espaciais de objetos relativamente ao observador (localização egocêntrica bem mais fina (estereopsia, mas isso ocorre em, apenas, uma faixa muito estreita (o horóptero. Aquém e além dela, acham-se presentes diplopia e confusão, sendo necessária supressão fisiológica (cortical para evitá-las. Analisa-se a geometria do horóptero e suas implicações fisiológicas (o desvio de Hillebrand, a partição de Kundt, a área de Panum, assim como aspectos clínicos da visão binocular normal (percepção simultânea, fusão, visão estereoscópica e de adaptações a seus estados afetados (supressão patológica, ambliopia, correspondência visual anômala.The binocular vision of human beings is given by the almost complete superimposition of the monocular visual fields, which allows a finer perceptual discrimination of the egocentric localization of objects in space (stereopsis but only within a very narrow band (the horopter. Before and beyond it, diplopia and confusion are present, so that a physiologic (cortical suppression is necessary to avoid them to become conscious. The geometry of the horopter and its physiologic implications (Hillebrand's deviation, Kundt's partition, Panum's area, stereoscopic vision are analyzed, as well as some clinical aspects of the normal binocular vision (simultaneous perception, fusion, stereoscopic vision and of adaptations to abnormal states (pathologic suppression, amblyopia, abnormal retinal correspondence.

  5. Spatial-frequency dependent binocular imbalance in amblyopia.

    Kwon, MiYoung; Wiecek, Emily; Dakin, Steven C; Bex, Peter J

    2015-11-25

    While amblyopia involves both binocular imbalance and deficits in processing high spatial frequency information, little is known about the spatial-frequency dependence of binocular imbalance. Here we examined binocular imbalance as a function of spatial frequency in amblyopia using a novel computer-based method. Binocular imbalance at four spatial frequencies was measured with a novel dichoptic letter chart in individuals with amblyopia, or normal vision. Our dichoptic letter chart was composed of band-pass filtered letters arranged in a layout similar to the ETDRS acuity chart. A different chart was presented to each eye of the observer via stereo-shutter glasses. The relative contrast of the corresponding letter in each eye was adjusted by a computer staircase to determine a binocular Balance Point at which the observer reports the letter presented to either eye with equal probability. Amblyopes showed pronounced binocular imbalance across all spatial frequencies, with greater imbalance at high compared to low spatial frequencies (an average increase of 19%, p imbalance may be useful for diagnosing amblyopia and as an outcome measure for recovery of binocular vision following therapy.

  6. Relating binocular and monocular vision in strabismic and anisometropic amblyopia.

    Agrawal, Ritwick; Conner, Ian P; Odom, J V; Schwartz, Terry L; Mendola, Janine D

    2006-06-01

    To examine deficits in monocular and binocular vision in adults with amblyopia and to test the following 2 hypotheses: (1) Regardless of clinical subtype, the degree of impairment in binocular integration predicts the pattern of monocular acuity deficits. (2) Subjects who lack binocular integration exhibit the most severe interocular suppression. Seven subjects with anisometropia, 6 subjects with strabismus, and 7 control subjects were tested. Monocular tests included Snellen acuity, grating acuity, Vernier acuity, and contrast sensitivity. Binocular tests included Titmus stereo test, binocular motion integration, and dichoptic contrast masking. As expected, both groups showed deficits in monocular acuity, with subjects with strabismus showing greater deficits in Vernier acuity. Both amblyopic groups were then characterized according to the degree of residual stereoacuity and binocular motion integration ability, and 67% of subjects with strabismus compared with 29% of subjects with anisometropia were classified as having "nonbinocular" vision according to our criterion. For this nonbinocular group, Vernier acuity is most impaired. In addition, the nonbinocular group showed the most dichoptic contrast masking of the amblyopic eye and the least dichoptic contrast masking of the fellow eye. The degree of residual binocularity and interocular suppression predicts monocular acuity and may be a significant etiological mechanism of vision loss.

  7. Assessing Attention Deficit by Binocular Rivalry.

    Amador-Campos, Juan Antonio; Aznar-Casanova, J Antonio; Ortiz-Guerra, Juan Jairo; Moreno-Sánchez, Manuel; Medina-Peña, Antonio

    2015-12-01

    To determine whether the frequency and duration of the periods of suppression of a percept in a binocular rivalry (BR) task can be used to distinguish between participants with ADHD and controls. A total of 122 participants (6-15 years) were assigned to three groups: ADHD-Combined (ADHD-C), ADHD-Predominantly Inattentive (ADHD-I), and controls. They each performed a BR task and two measures were recorded: alternation rate and duration of exclusive dominance periods. ADHD-C group presented fewer alternations and showed greater variability than did the control group; results for the ADHD-I group being intermediate between the two. The duration of dominance periods showed a differential profile: In control group, it remained stable over time, whereas in the clinical groups, it decreased logarithmically as the task progressed. The differences between groups in relation to the BR indicators can be attributed to the activity of involuntary inhibition. © The Author(s) 2013.

  8. Comparison of the diagnostic value of MR imaging and ophthalmoscopy for the staging of retinoblastoma

    Khurana, Aman; Wan, Wenshuai; Yeom, Kristen [Stanford University, Department of Radiology, Stanford, CA (United States); Eisenhut, Christina A. [Technical University of Munich, Department of Radiology, Munich (Germany); Ebrahimi, Katayoon B. [Johns Hopkins University, Department of Ocular Oncology, Baltimore, MD (United States); Patel, Chirag [University of California Davis, Department of Radiology, Davis, CA (United States); O' Brien, Joan M. [University of Pennsylvania, Department of Ophthalmology, Philadelphia, PA (United States); Daldrup-Link, Heike E. [Stanford University, Department of Radiology, Stanford, CA (United States); Stanford University, Department of Radiology, Pediatric Radiology Section, Lucile Packard Children' s Hospital, Stanford, CA (United States)

    2013-05-15

    To compare the diagnostic value of magnetic resonance (MR) imaging and ophthalmoscopy for staging of retinoblastoma. MR and ophthalmoscopic images of 36 patients who underwent enucleation were evaluated retrospectively following institutional review board approval. Histopathology being the standard of reference, the sensitivity and specificity of both diagnostic modalities were compared regarding growth pattern, iris neoangiogenesis, retinal detachment, vitreous seeds and optic nerve invasion. Data were analysed via McNemar's test. Both investigations showed no significant difference in accuracy for the detection of different tumour growth patterns (P = 0.80). Vitreous seeding detection was superior by ophthalmoscopy (P < 0.001). For prelaminar optic nerve invasion, MR imaging showed similar sensitivity as ophthalmoscopy but increased specificity of 40 % (CI 0.12-0.74) vs. 20 % (0.03-0.56). MR detected optic nerve involvement past the lamina cribrosa with a sensitivity of 80 % (0.28-0.99) and a specificity of 74 % (0.55-0.88). The absence of optic nerve enhancement excluded histopathological infiltration, but the presence of optic nerve enhancement included a high number of false positives (22-24 %). Ophthalmoscopy remains the method of choice for determining extent within the globe while MR imaging is useful for evaluating extraocular tumour extension. Thus, both have their own strengths and contribute uniquely to the staging of retinoblastoma. (orig.)

  9. Imaging of the optic disk in caring for patients with glaucoma: ophthalmoscopy and photography remain the gold standard.

    Spaeth, George L; Reddy, Swathi C

    2014-01-01

    Optic disk imaging is integral to the diagnosis and treatment of patients with glaucoma. We discuss the various forms of imaging the optic nerve, including ophthalmoscopy, photography, and newer imaging modalities, including optical coherence tomography (OCT), confocal scanning laser ophthalmoscopy (HRT), and scanning laser polarimetry (GDx), specifically highlighting their benefits and disadvantages. We argue that ophthalmoscopy and photography remain the gold standard of imaging due to portability, ease of interpretation, and the presence of a large database of images for comparison. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. A buyer's and user's guide to astronomical telescopes & binoculars

    Mullaney, James

    2007-01-01

    This exciting, upbeat new guide provides an extensive overview of binoculars and telescopes. It includes detailed up-to-date information on sources, selection and use of virtually every major type, brand and model of such instruments on today's market.

  11. Amblyopia and the binocular approach to its therapy.

    Hess, Robert F; Thompson, Benjamin

    2015-09-01

    There is growing evidence that abnormal binocular interactions play a key role in amblyopia. In particular, stronger suppression of the amblyopic eye has been associated with poorer amblyopic eye visual acuity and a new therapy has been described that directly targets binocular function and has been found to improve both monocular and binocular vision in adults and children with amblyopia. Furthermore, non-invasive brain stimulation techniques that alter excitation and inhibition within the visual cortex have been shown to improve vision in the amblyopic eye. The aim of this review is to summarize this previous work and interpret the therapeutic effects of binocular therapy and non-invasive brain stimulation in the context of three potential neural mechanisms; active inhibition of signals from the amblyopic eye, attenuation of information from the amblyopic eye and metaplasticity of synaptic long term potentiation and long term depression. Copyright © 2015. Published by Elsevier Ltd.

  12. Binocular Rivalry in a Competitive Neural Network with Synaptic Depression

    Kilpatrick, Zachary P.; Bressloff, Paul C.

    2010-01-01

    We study binocular rivalry in a competitive neural network with synaptic depression. In particular, we consider two coupled hypercolums within primary visual cortex (V1), representing orientation selective cells responding to either left or right

  13. Objective Evaluation of Visual Fatigue Using Binocular Fusion Maintenance.

    Hirota, Masakazu; Morimoto, Takeshi; Kanda, Hiroyuki; Endo, Takao; Miyoshi, Tomomitsu; Miyagawa, Suguru; Hirohara, Yoko; Yamaguchi, Tatsuo; Saika, Makoto; Fujikado, Takashi

    2018-03-01

    In this study, we investigated whether an individual's visual fatigue can be evaluated objectively and quantitatively from their ability to maintain binocular fusion. Binocular fusion maintenance (BFM) was measured using a custom-made binocular open-view Shack-Hartmann wavefront aberrometer equipped with liquid crystal shutters, wherein eye movements and wavefront aberrations were measured simultaneously. Transmittance in the liquid crystal shutter in front of the subject's nondominant eye was reduced linearly, and BFM was determined from the transmittance at the point when binocular fusion was broken and vergence eye movement was induced. In total, 40 healthy subjects underwent the BFM test and completed a questionnaire regarding subjective symptoms before and after a visual task lasting 30 minutes. BFM was significantly reduced after the visual task ( P eye symptom score (adjusted R 2 = 0.752, P devices, such as head-mount display, objectively.

  14. Binocular vision in amblyopia: structure, suppression and plasticity.

    Hess, Robert F; Thompson, Benjamin; Baker, Daniel H

    2014-03-01

    The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cortex and, on the basis of initial data, appear to improve both binocular and monocular visual function, even in adults with amblyopia. The aim of this review is to provide an overview of recent studies that have investigated the structure, measurement and treatment of binocular vision in observers with strabismic, anisometropic and mixed amblyopia. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

  15. A binocular iPad treatment for amblyopic children.

    Li, S L; Jost, R M; Morale, S E; Stager, D R; Dao, L; Stager, D; Birch, E E

    2014-10-01

    Monocular amblyopia treatment (patching or penalization) does not always result in 6/6 vision and amblyopia often recurs. As amblyopia arises from abnormal binocular visual experience, we evaluated the effectiveness of a novel home-based binocular amblyopia treatment. Children (4-12 y) wore anaglyphic glasses to play binocular games on an iPad platform for 4 h/w for 4 weeks. The first 25 children were assigned to sham games and then 50 children to binocular games. Children in the binocular group had the option of participating for an additional 4 weeks. Compliance was monitored with calendars and tracking fellow eye contrast settings. About half of the children in each group were also treated with patching at a different time of day. Best-corrected visual acuity, suppression, and stereoacuity were measured at baseline, at the 4- and 8-week outcome visits, and 3 months after cessation of treatment. Mean (±SE) visual acuity improved in the binocular group from 0.47±0.03 logMAR at baseline to 0.39±0.03 logMAR at 4 weeks (P<0.001); there was no significant change for the sham group. The effect of binocular games on visual acuity did not differ for children who were patched vs those who were not. The median stereoacuity remained unchanged in both groups. An additional 4 weeks of treatment did not yield additional visual acuity improvement. Visual acuity improvements were maintained for 3 months after the cessation of treatment. Binocular iPad treatment rapidly improved visual acuity, and visual acuity was stable for at least 3 months following the cessation of treatment.

  16. Neuroimaging of amblyopia and binocular vision: a review

    Joly, Olivier; Frankó, Edit

    2014-01-01

    Amblyopia is a cerebral visual impairment considered to derive from abnormal visual experience (e.g., strabismus, anisometropia). Amblyopia, first considered as a monocular disorder, is now often seen as a primarily binocular disorder resulting in more and more studies examining the binocular deficits in the patients. The neural mechanisms of amblyopia are not completely understood even though they have been investigated with electrophysiological recordings in animal models and more recently ...

  17. Binocular vision in amblyopia : structure, suppression and plasticity

    Hess, Robert F; Thompson, Benjamin; Baker, Daniel Hart

    2014-01-01

    The amblyopic visual system was once considered to be structurally monocular. However, it now evident that the capacity for binocular vision is present in many observers with amblyopia. This has led to new techniques for quantifying suppression that have provided insights into the relationship between suppression and the monocular and binocular visual deficits experienced by amblyopes. Furthermore, new treatments are emerging that directly target suppressive interactions within the visual cor...

  18. A binocular approach to treating amblyopia: antisuppression therapy.

    Hess, Robert F; Mansouri, Behzad; Thompson, Benjamin

    2010-09-01

    We developed a binocular treatment for amblyopia based on antisuppression therapy. A novel procedure is outlined for measuring the extent to which the fixing eye suppresses the fellow amblyopic eye. We hypothesize that suppression renders a structurally binocular system, functionally monocular. We demonstrate using three strabismic amblyopes that information can be combined normally between their eyes under viewing conditions where suppression is reduced. Also, we show that prolonged periods of viewing (under the artificial conditions of stimuli of different contrast in each eye) during which information from the two eyes is combined leads to a strengthening of binocular vision in such cases and eventual combination of binocular information under natural viewing conditions (stimuli of the same contrast in each eye). Concomitant improvement in monocular acuity of the amblyopic eye occurs with this reduction in suppression and strengthening of binocular fusion. Furthermore, in each of the three cases, stereoscopic function is established. This provides the basis for a new treatment of amblyopia, one that is purely binocular and aimed at reducing suppression as a first step.

  19. Neuroimaging of amblyopia and binocular vision: a review.

    Joly, Olivier; Frankó, Edit

    2014-01-01

    Amblyopia is a cerebral visual impairment considered to derive from abnormal visual experience (e.g., strabismus, anisometropia). Amblyopia, first considered as a monocular disorder, is now often seen as a primarily binocular disorder resulting in more and more studies examining the binocular deficits in the patients. The neural mechanisms of amblyopia are not completely understood even though they have been investigated with electrophysiological recordings in animal models and more recently with neuroimaging techniques in humans. In this review, we summarize the current knowledge about the brain regions that underlie the visual deficits associated with amblyopia with a focus on binocular vision using functional magnetic resonance imaging. The first studies focused on abnormal responses in the primary and secondary visual areas whereas recent evidence shows that there are also deficits at higher levels of the visual pathways within the parieto-occipital and temporal cortices. These higher level areas are part of the cortical network involved in 3D vision from binocular cues. Therefore, reduced responses in these areas could be related to the impaired binocular vision in amblyopic patients. Promising new binocular treatments might at least partially correct the activation in these areas. Future neuroimaging experiments could help to characterize the brain response changes associated with these treatments and help devise them.

  20. Neuroimaging of amblyopia and binocular vision: a review

    Olivier eJoly

    2014-08-01

    Full Text Available Amblyopia is a cerebral visual impairment considered to derive from abnormal visual experience (e.g., strabismus, anisometropia. Amblyopia, first considered as a monocular disorder, is now often seen as a primarily binocular disorder resulting in more and more studies examining the binocular deficits in the patients. The neural mechanisms of amblyopia are not completely understood even though they have been investigated with electrophysiological recordings in animal models and more recently with neuroimaging techniques in humans. In this review, we summarise the current knowledge about the brain regions that underlie the visual deficits associated with amblyopia with a focus on binocular vision using functional magnetic resonance imaging (fMRI. The first studies focused on abnormal responses in the primary and secondary visual areas whereas recent evidence show that there are also deficits at higher levels of the visual pathways within the parieto-occipital and temporal cortices. These higher level areas are part of the cortical network involved in 3D vision from binocular cues. Therefore, reduced responses in these areas could be related to the impaired binocular vision in amblyopic patients. Promising new binocular treatments might at least partially correct the activation in these areas. Future neuroimaging experiments could help to characterise the brain response changes associated with these treatments and help devise them.

  1. Reward modulates perception in binocular rivalry.

    Marx, Svenja; Einhäuser, Wolfgang

    2015-01-14

    Our perception does not provide us with an exact imprint of the outside world, but is continuously adapted to our internal expectations, task sets, and behavioral goals. Although effects of reward-or value in general-on perception therefore seem likely, how valuation modulates perception and how such modulation relates to attention is largely unknown. We probed effects of reward on perception by using a binocular-rivalry paradigm. Distinct gratings drifting in opposite directions were presented to each observer's eyes. To objectify their subjective perceptual experience, the optokinetic nystagmus was used as measure of current perceptual dominance. In a first experiment, one of the percepts was either rewarded or attended. We found that reward and attention similarly biased perception. In a second experiment, observers performed an attentionally demanding task either on the rewarded stimulus, the other stimulus, or both. We found that-on top of an attentional effect on perception-at each level of attentional load, reward still modulated perception by increasing the dominance of the rewarded percept. Similarly, penalizing one percept increased dominance of the other at each level of attentional load. In turn, rewarding-and similarly nonpunishing-a percept yielded performance benefits that are typically associated with selective attention. In conclusion, our data show that value modulates perception in a similar way as the volitional deployment of attention, even though the relative effect of value is largely unaffected by an attention task. © 2015 ARVO.

  2. Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update

    Bing Zhang

    2017-11-01

    Full Text Available Adaptive optics scanning laser ophthalmoscopy (AO-SLO has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics (AO and AO-SLO. Then it compares AO-SLO with conventional imaging methods (fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography and other AO techniques (adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherence tomography. Furthermore, an update of current research situation in AO-SLO is made based on different fundus structures as photoreceptors (cones and rods, fundus vessels, retinal pigment epithelium layer, retinal nerve fiber layer, ganglion cell layer and lamina cribrosa. Finally, this review indicates possible research directions of AO-SLO in future.

  3. Perceptual Relearning of Binocular Fusion and Stereoacuity After Brain Injury.

    Schaadt, Anna-Katharina; Schmidt, Lena; Reinhart, Stefan; Adams, Michaela; Garbacenkaite, Ruta; Leonhardt, Eva; Kuhn, Caroline; Kerkhoff, Georg

    2014-06-01

    Brain lesions may disturb binocular fusion and stereopsis, leading to blurred vision, diplopia, and reduced binocular depth perception for which no evaluated treatment is currently available. Objective The study evaluated the effects of a novel binocular vision treatment designed to improve convergent fusional amplitude and stereoacuity in patients with stroke or traumatic brain injury (TBI). Methods Patients (20 in all: 11 with stroke, 9 with TBI) were tested in fusional convergence, stereoacuity, near/far visual acuity, accommodation, and subjective binocular reading time until diplopia emerged at 6 different time points. All participants were treated in a single subject baseline design, with 3 baseline assessments before treatment (pretherapy), an assessment immediately after a 6-week treatment period (posttherapy), and 2 follow-up tests 3 and 6 months after treatment. Patients received a novel fusion and dichoptic training using 3 different devices to slowly increase fusional and disparity angles. Results At pretherapy, the stroke and TBI groups showed severe impairments in convergent fusional range, stereoacuity, subjective reading duration, and partially in accommodation (only TBI group). After treatment, both groups showed considerable improvements in all these variables as well as slightly increased near visual acuity. No significant changes were observed during the pretherapy and follow-up periods, ruling out spontaneous recovery and demonstrating long-term stability of binocular treatment effects. Conclusions This proof-of-principle study indicates a substantial treatment-induced plasticity of the lesioned brain in the relearning of binocular fusion and stereovision, thus providing new, effective rehabilitation strategies to treat binocular vision deficits resulting from permanent visual cortical damage. © The Author(s) 2013.

  4. Binocular function in patients with pseudophakic monovision.

    Ito, Misae; Shimizu, Kimiya; Niida, Takahiro; Amano, Rie; Ishikawa, Hitoshi

    2014-08-01

    To evaluate the relationship between ocular deviation and stereopsis and fusion in patients who had pseudophakic monovision surgery. Department of Ophthalmology, Kitasato University Hospital, Kanagawa, Japan. Retrospective comparative case series. Patients had surgical monovision correction with monofocal intraocular lens placement followed by routine postoperative examinations. The alternate prism cover test was used to measure motor alignment. Sensory tests for binocularity included sensory fusion determinations using the Worth 4-dot test, near stereopsis test, and fusion amplitude measured with a prism bar. Patients with monovision were categorized as having small-angle exophoria (≤10.0 prism diopters [Δ]) or moderate-angle exophoria (>10.0 Δ). This study comprised 60 patients with a mean age of 70.2 years ± 7.7 (SD). The difference in the mean stereopsis values between patients with small-angle exophoria and patients with moderate-angle exophoria was statistically significant (P<.001). In the moderate-angle exophoria group, 10 patients (62.5%) developed intermittent exotropia after surgery; however, no serious ocular deviation problems were observed. The fusion amplitudes in patients with pseudophakic monovision were approximately similar to normal values. Patients with moderate-angle exophoria were more likely to fail the Worth 4-dot test than those with small-angle exophoria. In patients with pseudophakic monovision having a near exophoria angle of more than 10.0 Δ, the possibility of changes in ocular deviation and stereopsis after surgery is a concern. Moreover, the application of monovision in patients with a previous moderate-angle exophoria should be carefully considered. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  5. A McCollough Effect Generated at Binocular Site

    Qiujie Weng

    2011-05-01

    Full Text Available Following exposures to alternating gratings with unique combination of orientation and colors, an achromatic grating would appear tinted with its perceived color contingent on the grating's orientation. This orientation-contingent color after effect is called the McCollough effect. The lack of interocular transfer of the McCollough effect suggests that the McCollough effect is primarily established in monocular channels. Here we explored the possibility that the McCollough effect can be induced at a binocular site. During adaptation, a red vertical grating and a green horizontal grating are dichoptically presented to the two eyes. In the ‘binocular rivalry’ condition, these two gratings were constantly presented throughout the adaptation duration and subjects experienced the rivalry between the two gratings. In the ‘physical alternation’ condition, the two dichoptic gratings physically alternated during adaptation, perceptually similar to binocular rivalry. Interestingly, following dichoptic adaptation either in the rivalry condition or in the physical alternation condition, a binocularly viewed achromatic test grating appeared colored depending on its orientation: a vertical grating appeared greenish and a horizontal grating pinkish. In other words, we observed a McCollough effect following dichoptic adaptation, which can only be explained by a binocular site of orientation-contingent color adaptation.

  6. Diagnostic accuracy of direct ophthalmoscopy for detection of diabetic retinopathy using fundus photographs as a reference standard.

    Ahsan, Shahid; Basit, Abdul; Ahmed, Kazi Rumana; Ali, Liaquat; Shaheen, Fariha; Ulhaque, Muhammad Saif; Fawwad, Asher

    2014-01-01

    To determine the diagnostic accuracy of direct ophthalmoscopy for the presence and severity of diabetic retinopathy (DR) using fundus photographs as a reference standard. Patients with type 2 diabetes attending the outpatient department (OPD) of a tertiary care diabetes center, from October 2009 to March 2010 were recruited in the study after obtaining signed informed consent. Patients with type 1 diabetes and gestational diabetes or having eye problems were excluded. After checking visual acuity, direct ophthalmoscopy of each eye was done by diabetologist, followed by photography of two fields of retina by fundus camera. DR was graded by a retinal specialist, according to International Diabetic Retinopathy Disease Severity Scale. According to severity, patients with DR were grouped into non-sight threatening diabetic retinopathy (NSTDR) and sight threatening diabetic retinopathy (STDR). Sensitivity and specificity of direct ophthalmoscopy for detection of any retinopathy, NSTDR and STDR was calculated. A total of 728 eyes were examined by direct ophthalmoscopy as well as fundus photography. Sensitivity (95% CI) of direct ophthalmoscopy for any retinopathy, NSTDR and STDR was found to be 55.67% (50.58-60.78), 37.63% (32.67-42.59) and 68.25% (63.48-73.02) respectively. Whereas, specificity of direct ophthalmoscopy was found to be 76.78% (72.45-81.11), 71.27% (CI: 66.63-75.91) and 90.0% (86.93-93.07) for any retinopathy, NSTDR and STDR respectively. The sensitivity and specificity of direct ophthalmoscopy performed by the diabetologist for the presence and severity of DR was lower compared to the recommended level of sensitivity and specificity of a screening test of DR. Copyright © 2014 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  7. New insights into amblyopia: binocular therapy and noninvasive brain stimulation.

    Hess, Robert F; Thompson, Benjamin

    2013-02-01

    The current approach to the treatment of amblyopia is problematic for a number of reasons. First, it promotes recovery of monocular vision but because it is not designed to promote binocularity, its binocular outcomes often are disappointing. Second, compliance is poor and variable. Third, the effectiveness of the treatment is thought to decrease with increasing age. We discuss 2 new approaches aimed at recovering visual function in adults with amblyopia. The first is a binocular approach to amblyopia treatment that is showing promise in initial clinical studies. The second is still in development and involves the use of well-established noninvasive brain stimulation techniques to temporarily alter the balance of excitation and inhibition in the visual cortex. Copyright © 2013 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.

  8. Binocular iPad treatment for amblyopia in preschool children.

    Birch, Eileen E; Li, Simone L; Jost, Reed M; Morale, Sarah E; De La Cruz, Angie; Stager, David; Dao, Lori; Stager, David R

    2015-02-01

    Recent experimental evidence supports a role for binocular visual experience in the treatment of amblyopia. The purpose of this study was to determine whether repeated binocular visual experience with dichoptic iPad games could effectively treat amblyopia in preschool children. A total of 50 consecutive amblyopic preschool children 3-6.9 years of age were assigned to play sham iPad games (first 5 children) or binocular iPad games (n = 45) for at least 4 hours per week for 4 weeks. Thirty (67%) children in the binocular iPad group and 4 (80%) in the sham iPad group were also treated with patching at a different time of day. Visual acuity and stereoacuity were assessed at baseline, at 4 weeks, and at 3 months after the cessation of game play. The sham iPad group had no significant improvement in visual acuity (t4 = 0.34, P = 0.75). In the binocular iPad group, mean visual acuity (plus or minus standard error) improved from 0.43 ± 0.03 at baseline to 0.34 ± 0.03 logMAR at 4 weeks (n = 45; paired t44 = 4.93; P iPad games for ≥8 hours (≥50% compliance) had significantly more visual acuity improvement than children who played 0-4 hours (t43 = 4.21, P = 0.0001). Repeated binocular experience, provided by dichoptic iPad game play, was more effective than sham iPad game play as a treatment for amblyopia in preschool children. Copyright © 2015 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  9. Refractive and binocular vision status of optometry students, Ghana ...

    To investigate the refractive and non-strabismic binocular vision status of Optometry students in University of Cape Coast, Ghana and to establish any associations between these conditions. A cross sectional study of 105 Optometry students were taken through a comprehensive optometric examination to investigate the ...

  10. Visual comfort of binocular and 3D displays

    Kooi, F.L.; Toet, A.

    2004-01-01

    Imperfections in binocular image pairs can cause serious viewing discomfort. For example, in stereo vision systems eye strain is caused by unintentional mismatches between the left and right eye images (stereo imperfections). Head-mounted displays can induce eye strain due to optical misalignments.

  11. SOME ASPECTS OF SCANNING LASER OPHTHALMOSCOPY IN THE DIAGNOSTICS OF OPHTHALMOPATHOLOGY

    S. A. Kochergin

    2017-01-01

    Full Text Available The exact diagnosis of the fundus pathology requires the most modern equipment use. This is mandatory for the selection of the most complete therapy and monitoring of ongoing treatment. At present, the method of scanning laser ophthalmoscopy is widely spread. However, for the earliest detection of the smallest pathological changes, data of the normal ocular fundus state using a scanning laser ophthalmoscope is necessary. Thus, the purpose of our research becomes relevant. Purpose: to give a characteristic of the fundus in patients without concomitant pathology with using various modes of a scanning laser ophthalmoscope. Patients and methods. 116 people (232 eyes at the age from 17 to 71 years (mean age 32.5±12 years were examined. The patients were divided into two groups. Group I: 81 patients (162 eyes with different ophthalmopathology. Group II: 35 people (70 eyes — practically healthy and did not have an anamnesis of consulting an ophthalmologist. Diagnosis of the patients’ fundus was performed using a scanning laser ophthalmoscopy with retro-mode imaging and autofluorescence registration. Results. After the conducted research features and regularities of the reflectivity distribution of laser beams from the fundus structures are revealed. Also a characteristic of various anatomical formations and zones of the fundus in the normal conditions is given when examined by a scanning laser ophthalmoscope. An algorithm for examining patients and analyzing the images was developed. Conclusion. The use of scanning laser ophthalmoscopy made possible to take a fresh look at the algorithms of diagnosing patients with fundus pathology. Understanding the normal conditions ofundus allowed an earlier detection of the smallest pathological changes in the retina. 

  12. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with multimodal photoacoustic ophthalmoscopy

    Zhang, Xiangyang; Zhang, Hao F.; Zhou, Lixiang; Jiao, Shuliang

    2012-02-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective vs. exacerbate) in the RPE in the aging process. We successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  13. Symptomatology associated with accommodative and binocular vision anomalies.

    García-Muñoz, Ángel; Carbonell-Bonete, Stela; Cacho-Martínez, Pilar

    2014-01-01

    To determine the symptoms associated with accommodative and non-strabismic binocular dysfunctions and to assess the methods used to obtain the subjects' symptoms. We conducted a scoping review of articles published between 1988 and 2012 that analysed any aspect of the symptomatology associated with accommodative and non-strabismic binocular dysfunctions. The literature search was performed in Medline (PubMed), CINAHL, PsycINFO and FRANCIS. A total of 657 articles were identified, and 56 met the inclusion criteria. We found 267 different ways of naming the symptoms related to these anomalies, which we grouped into 34 symptom categories. Of the 56 studies, 35 employed questionnaires and 21 obtained the symptoms from clinical histories. We found 11 questionnaires, of which only 3 had been validated: the convergence insufficiency symptom survey (CISS V-15) and CIRS parent version, both specific for convergence insufficiency, and the Conlon survey, developed for visual anomalies in general. The most widely used questionnaire (21 studies) was the CISS V-15. Of the 34 categories of symptoms, the most frequently mentioned were: headache, blurred vision, diplopia, visual fatigue, and movement or flicker of words at near vision, which were fundamentally related to near vision and binocular anomalies. There is a wide disparity of symptoms related to accommodative and binocular dysfunctions in the scientific literature, most of which are associated with near vision and binocular dysfunctions. The only psychometrically validated questionnaires that we found (n=3) were related to convergence insufficiency and to visual dysfunctions in general and there no specific questionnaires for other anomalies. Copyright © 2014. Published by Elsevier Espana.

  14. Monocular perceptual learning of contrast detection facilitates binocular combination in adults with anisometropic amblyopia.

    Chen, Zidong; Li, Jinrong; Liu, Jing; Cai, Xiaoxiao; Yuan, Junpeng; Deng, Daming; Yu, Minbin

    2016-02-01

    Perceptual learning in contrast detection improves monocular visual function in adults with anisometropic amblyopia; however, its effect on binocular combination remains unknown. Given that the amblyopic visual system suffers from pronounced binocular functional loss, it is important to address how the amblyopic visual system responds to such training strategies under binocular viewing conditions. Anisometropic amblyopes (n = 13) were asked to complete two psychophysical supra-threshold binocular summation tasks: (1) binocular phase combination and (2) dichoptic global motion coherence before and after monocular training to investigate this question. We showed that these participants benefited from monocular training in terms of binocular combination. More importantly, the improvements observed with the area under log CSF (AULCSF) were found to be correlated with the improvements in binocular phase combination.

  15. Reinforcement of perceptual inference: reward and punishment alter conscious visual perception during binocular rivalry

    Gregor eWilbertz

    2014-12-01

    Full Text Available Perception is an inferential process, which becomes immediately evident when sensory information is conflicting or ambiguous and thus allows for more than one perceptual interpretation. Thinking the idea of perception as inference through to the end results in a blurring of boundaries between perception and action selection, as perceptual inference implies the construction of a percept as an active process. Here we therefore wondered whether perception shares a key characteristic of action selection, namely that it is shaped by reinforcement learning. In two behavioral experiments, we used binocular rivalry to examine whether perceptual inference can be influenced by the association of perceptual outcomes with reward or punishment, respectively, in analogy to instrumental conditioning. Binocular rivalry was evoked by two orthogonal grating stimuli presented to the two eyes, resulting in perceptual alternations between the two gratings. Perception was tracked indirectly and objectively through a target detection task, which allowed us to preclude potential reporting biases. Monetary rewards or punishments were given repeatedly during perception of only one of the two rivalling stimuli. We found an increase in dominance durations for the percept associated with reward, relative to the non-rewarded percept. In contrast, punishment led to an increase of the non-punished compared to a relative decrease of the punished percept. Our results show that perception shares key characteristics with action selection, in that it is influenced by reward and punishment in opposite directions, thus narrowing the gap between the conceptually separated domains of perception and action selection. We conclude that perceptual inference is an adaptive process that is shaped by its consequences.

  16. The disparate histories of binocular vision and binaural hearing.

    Wade, Nicholas J

    2018-01-01

    Vision and hearing are dependent on disparities of spatial patterns received by two eyes and on time and intensity differences to two ears. However, the experiences of a single world have masked attention to these disparities. While eyes and ears are paired, there has not been parity in the attention directed to their functioning. Phenomena involving binocular vision were commented upon since antiquity whereas those about binaural hearing are much more recent. This history is compared with respect to the experimental manipulations of dichoptic and dichotic stimuli and the instruments used to stimulate the paired organs. Binocular color mixing led to studies of binaural hearing and direction and distance in visual localization were analyzed before those for auditory localization. Experimental investigations began in the nineteenth century with the invention of instruments like the stereoscope and pseudoscope, soon to be followed by their binaural equivalents, the stethophone and pseudophone.

  17. Modeling the convergence accommodation of stereo vision for binocular endoscopy.

    Gao, Yuanqian; Li, Jinhua; Li, Jianmin; Wang, Shuxin

    2018-02-01

    The stereo laparoscope is an important tool for achieving depth perception in robot-assisted minimally invasive surgery (MIS). A dynamic convergence accommodation algorithm is proposed to improve the viewing experience and achieve accurate depth perception. Based on the principle of the human vision system, a positional kinematic model of the binocular view system is established. The imaging plane pair is rectified to ensure that the two rectified virtual optical axes intersect at the fixation target to provide immersive depth perception. Stereo disparity was simulated with the roll and pitch movements of the binocular system. The chessboard test and the endoscopic peg transfer task were performed, and the results demonstrated the improved disparity distribution and robustness of the proposed convergence accommodation method with respect to the position of the fixation target. This method offers a new solution for effective depth perception with the stereo laparoscopes used in robot-assisted MIS. Copyright © 2017 John Wiley & Sons, Ltd.

  18. ASSOCIATIONS BETWEEN MACULAR EDEMA AND CIRCULATORY STATUS IN EYES WITH RETINAL VEIN OCCLUSION: An Adaptive Optics Scanning Laser Ophthalmoscopy Study.

    Iida, Yuto; Muraoka, Yuki; Uji, Akihito; Ooto, Sotaro; Murakami, Tomoaki; Suzuma, Kiyoshi; Tsujikawa, Akitaka; Arichika, Shigeta; Takahashi, Ayako; Miwa, Yuko; Yoshimura, Nagahisa

    2017-10-01

    To investigate associations between parafoveal microcirculatory status and foveal pathomorphology in eyes with macular edema (ME) secondary to retinal vein occlusion (RVO). Ten consecutive patients (10 eyes) with acute retinal vein occlusion were enrolled, 9 eyes of which received intravitreal ranibizumab (IVR) injections. Foveal morphologic changes were examined via optical coherence tomography (OCT), and parafoveal circulatory status was assessed via adaptive optics scanning laser ophthalmoscopy (AO-SLO). The mean parafoveal aggregated erythrocyte velocity (AEV) measured by adaptive optics scanning laser ophthalmoscopy in eyes with retinal vein occlusion was 0.99 ± 0.43 mm/second at baseline, which was significantly lower than that of age-matched healthy subjects (1.41 ± 0.28 mm/second, P = 0.042). The longitudinal adaptive optics scanning laser ophthalmoscopy examinations of each patient showed that parafoveal AEV was strongly inversely correlated with optical coherence tomography-measured central foveal thickness (CFT) over the entire observation period. Using parafoveal AEV and central foveal thickness measurements obtained at the first and second examinations, we investigated associations between differences in parafoveal AEV and central foveal thickness, which were significantly and highly correlated (r = -0.84, P = 0.002). Using adaptive optics scanning laser ophthalmoscopy in eyes with retinal vein occlusion macular edema, we could quantitatively evaluate the parafoveal AEV. A reduction or an increase in parafoveal AEV may be a clinical marker for the resolution or development/progression of macular edema respectively.

  19. Binocular depth processing in the ventral visual pathway

    Verhoef, Bram-Ernst; Vogels, Rufin; Janssen, Peter

    2016-01-01

    One of the most powerful forms of depth perception capitalizes on the small relative displacements, or binocular disparities, in the images projected onto each eye. The brain employs these disparities to facilitate various computations, including sensori-motor transformations (reaching, grasping), scene segmentation and object recognition. In accordance with these different functions, disparity activates a large number of regions in the brain of both humans and monkeys. Here, we review how di...

  20. Binocular Rivalry in a Competitive Neural Network with Synaptic Depression

    Kilpatrick, Zachary P.

    2010-01-01

    We study binocular rivalry in a competitive neural network with synaptic depression. In particular, we consider two coupled hypercolums within primary visual cortex (V1), representing orientation selective cells responding to either left or right eye inputs. Coupling between hypercolumns is dominated by inhibition, especially for neurons with dissimilar orientation preferences. Within hypercolumns, recurrent connectivity is excitatory for similar orientations and inhibitory for different orientations. All synaptic connections are modifiable by local synaptic depression. When the hypercolumns are driven by orthogonal oriented stimuli, it is possible to induce oscillations that are representative of binocular rivalry. We first analyze the occurrence of oscillations in a space-clamped version of the model using a fast-slow analys is, taking advantage of the fact that depression evolves much slower than population activity. We th en analyze the onset of oscillations in the full spatially extended system by carrying out a piecewise smooth stability analysis of single (winner-take-all) and double (fusion) bumps within the network. Although our stability analysis takes into account only instabilities associated with real eigenvalues, it identifies points of instability that are consistent with what is found numerically. In particular, we show that, in regions of parameter space where double bumps are unstable and no single bumps exist, binocular rivalry can arise as a slow alternation between either population supporting a bump. © 2010 Society for Industrial and Applied Mathematics.

  1. Standard Test Method for Measuring Binocular Disparity in Transparent Parts

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This test method covers the amount of binocular disparity that is induced by transparent parts such as aircraft windscreens, canopies, HUD combining glasses, visors, or goggles. This test method may be applied to parts of any size, shape, or thickness, individually or in combination, so as to determine the contribution of each transparent part to the overall binocular disparity present in the total “viewing system” being used by a human operator. 1.2 This test method represents one of several techniques that are available for measuring binocular disparity, but is the only technique that yields a quantitative figure of merit that can be related to operator visual performance. 1.3 This test method employs apparatus currently being used in the measurement of optical angular deviation under Method F 801. 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not con...

  2. Cone structure imaged with adaptive optics scanning laser ophthalmoscopy in eyes with nonneovascular age-related macular degeneration.

    Zayit-Soudry, Shiri; Duncan, Jacque L; Syed, Reema; Menghini, Moreno; Roorda, Austin J

    2013-11-15

    To evaluate cone spacing using adaptive optics scanning laser ophthalmoscopy (AOSLO) in eyes with nonneovascular AMD, and to correlate progression of AOSLO-derived cone measures with standard measures of macular structure. Adaptive optics scanning laser ophthalmoscopy images were obtained over 12 to 21 months from seven patients with AMD including four eyes with geographic atrophy (GA) and four eyes with drusen. Adaptive optics scanning laser ophthalmoscopy images were overlaid with color, infrared, and autofluorescence fundus photographs and spectral domain optical coherence tomography (SD-OCT) images to allow direct correlation of cone parameters with macular structure. Cone spacing was measured for each visit in selected regions including areas over drusen (n = 29), at GA margins (n = 14), and regions without drusen or GA (n = 13) and compared with normal, age-similar values. Adaptive optics scanning laser ophthalmoscopy imaging revealed continuous cone mosaics up to the GA edge and overlying drusen, although reduced cone reflectivity often resulted in hyporeflective AOSLO signals at these locations. Baseline cone spacing measures were normal in 13/13 unaffected regions, 26/28 drusen regions, and 12/14 GA margin regions. Although standard clinical measures showed progression of GA in all study eyes, cone spacing remained within normal ranges in most drusen regions and all GA margin regions. Adaptive optics scanning laser ophthalmoscopy provides adequate resolution for quantitative measurement of cone spacing at the margin of GA and over drusen in eyes with AMD. Although cone spacing was often normal at baseline and remained normal over time, these regions showed focal areas of decreased cone reflectivity. These findings may provide insight into the pathophysiology of AMD progression. (ClinicalTrials.gov number, NCT00254605).

  3. Direct ophthalmoscopy on YouTube: analysis of instructional YouTube videos' content and approach to visualization.

    Borgersen, Nanna Jo; Henriksen, Mikael Johannes Vuokko; Konge, Lars; Sørensen, Torben Lykke; Thomsen, Ann Sofia Skou; Subhi, Yousif

    2016-01-01

    Direct ophthalmoscopy is well-suited for video-based instruction, particularly if the videos enable the student to see what the examiner sees when performing direct ophthalmoscopy. We evaluated the pedagogical effectiveness of instructional YouTube videos on direct ophthalmoscopy by evaluating their content and approach to visualization. In order to synthesize main themes and points for direct ophthalmoscopy, we formed a broad panel consisting of a medical student, junior and senior physicians, and took into consideration book chapters targeting medical students and physicians in general. We then systematically searched YouTube. Two authors reviewed eligible videos to assess eligibility and extract data on video statistics, content, and approach to visualization. Correlations between video statistics and contents were investigated using two-tailed Spearman's correlation. We screened 7,640 videos, of which 27 were found eligible for this study. Overall, a median of 12 out of 18 points (interquartile range: 8-14 key points) were covered; no videos covered all of the 18 points assessed. We found the most difficulties in the approach to visualization of how to approach the patient and how to examine the fundus. Time spent on fundus examination correlated with the number of views per week (Spearman's ρ=0.53; P=0.029). Videos may help overcome the pedagogical issues in teaching direct ophthalmoscopy; however, the few available videos on YouTube fail to address this particular issue adequately. There is a need for high-quality videos that include relevant points, provide realistic visualization of the examiner's view, and give particular emphasis on fundus examination.

  4. Monocular perceptual learning of contrast detection facilitates binocular combination in adults with anisometropic amblyopia

    Chen, Zidong; Li, Jinrong; Liu, Jing; Cai, Xiaoxiao; Yuan, Junpeng; Deng, Daming; Yu, Minbin

    2016-01-01

    Perceptual learning in contrast detection improves monocular visual function in adults with anisometropic amblyopia; however, its effect on binocular combination remains unknown. Given that the amblyopic visual system suffers from pronounced binocular functional loss, it is important to address how the amblyopic visual system responds to such training strategies under binocular viewing conditions. Anisometropic amblyopes (n?=?13) were asked to complete two psychophysical supra-threshold binoc...

  5. Viewing geometry determines the contribution of binocular vision to the online control of grasping.

    Keefe, Bruce D; Watt, Simon J

    2017-12-01

    Binocular vision is often assumed to make a specific, critical contribution to online visual control of grasping by providing precise information about the separation between digits and object. This account overlooks the 'viewing geometry' typically encountered in grasping, however. Separation of hand and object is rarely aligned precisely with the line of sight (the visual depth dimension), and analysis of the raw signals suggests that, for most other viewing angles, binocular feedback is less precise than monocular feedback. Thus, online grasp control relying selectively on binocular feedback would not be robust to natural changes in viewing geometry. Alternatively, sensory integration theory suggests that different signals contribute according to their relative precision, in which case the role of binocular feedback should depend on viewing geometry, rather than being 'hard-wired'. We manipulated viewing geometry, and assessed the role of binocular feedback by measuring the effects on grasping of occluding one eye at movement onset. Loss of binocular feedback resulted in a significantly less extended final slow-movement phase when hand and object were separated primarily in the frontoparallel plane (where binocular information is relatively imprecise), compared to when they were separated primarily along the line of sight (where binocular information is relatively precise). Consistent with sensory integration theory, this suggests the role of binocular (and monocular) vision in online grasp control is not a fixed, 'architectural' property of the visuo-motor system, but arises instead from the interaction of viewer and situation, allowing robust online control across natural variations in viewing geometry.

  6. Binocular eye movement control and motion perception: what is being tracked?

    van der Steen, Johannes; Dits, Joyce

    2012-10-19

    We investigated under what conditions humans can make independent slow phase eye movements. The ability to make independent movements of the two eyes generally is attributed to few specialized lateral eyed animal species, for example chameleons. In our study, we showed that humans also can move the eyes in different directions. To maintain binocular retinal correspondence independent slow phase movements of each eye are produced. We used the scleral search coil method to measure binocular eye movements in response to dichoptically viewed visual stimuli oscillating in orthogonal direction. Correlated stimuli led to orthogonal slow eye movements, while the binocularly perceived motion was the vector sum of the motion presented to each eye. The importance of binocular fusion on independency of the movements of the two eyes was investigated with anti-correlated stimuli. The perceived global motion pattern of anti-correlated dichoptic stimuli was perceived as an oblique oscillatory motion, as well as resulted in a conjugate oblique motion of the eyes. We propose that the ability to make independent slow phase eye movements in humans is used to maintain binocular retinal correspondence. Eye-of-origin and binocular information are used during the processing of binocular visual information, and it is decided at an early stage whether binocular or monocular motion information and independent slow phase eye movements of each eye are produced during binocular tracking.

  7. Recent developments for the Large Binocular Telescope Guiding Control Subsystem

    Golota, T.; De La Peña, M. D.; Biddick, C.; Lesser, M.; Leibold, T.; Miller, D.; Meeks, R.; Hahn, T.; Storm, J.; Sargent, T.; Summers, D.; Hill, J.; Kraus, J.; Hooper, S.; Fisher, D.

    2014-07-01

    The Large Binocular Telescope (LBT) has eight Acquisition, Guiding, and wavefront Sensing Units (AGw units). They provide guiding and wavefront sensing capability at eight different locations at both direct and bent Gregorian focal stations. Recent additions of focal stations for PEPSI and MODS instruments doubled the number of focal stations in use including respective motion, camera controller server computers, and software infrastructure communicating with Guiding Control Subsystem (GCS). This paper describes the improvements made to the LBT GCS and explains how these changes have led to better maintainability and contributed to increased reliability. This paper also discusses the current GCS status and reviews potential upgrades to further improve its performance.

  8. The research of binocular vision ranging system based on LabVIEW

    Li, Shikuan; Yang, Xu

    2017-10-01

    Based on the study of the principle of binocular parallax ranging, a binocular vision ranging system is designed and built. The stereo matching algorithm is realized by LabVIEW software. The camera calibration and distance measurement are completed. The error analysis shows that the system fast, effective, can be used in the corresponding industrial occasions.

  9. Two eyes, one vision: binocular motion perception in human visual cortex

    Barendregt, M.

    2016-01-01

    An important aspect of human vision is the fact that it is binocular, i.e. that we have two eyes. As a result, the brain nearly always receives two slightly different images of the same visual scene. Yet, we only perceive a single image and thus our brain has to actively combine the binocular visual

  10. Depth of Monocular Elements in a Binocular Scene: The Conditions for da Vinci Stereopsis

    Cook, Michael; Gillam, Barbara

    2004-01-01

    Quantitative depth based on binocular resolution of visibility constraints is demonstrated in a novel stereogram representing an object, visible to 1 eye only, and seen through an aperture or camouflaged against a background. The monocular region in the display is attached to the binocular region, so that the stereogram represents an object which…

  11. The future of binocular rivalry research: reaching through a window on consciousness

    Klink, P. Christiaan; van Wezel, Richard Jack Anton; van Ee, Raymond; Miller, Steven M.

    2013-01-01

    Binocular rivalry is often considered an experimental window on the neural processes of consciousness. We propose three distinct approaches to exploit this window. First, one may look through the window, using binocular rivalry as a passive tool to dissociate unaltered sensory input from wavering

  12. Railway clearance intrusion detection method with binocular stereo vision

    Zhou, Xingfang; Guo, Baoqing; Wei, Wei

    2018-03-01

    In the stage of railway construction and operation, objects intruding railway clearance greatly threaten the safety of railway operation. Real-time intrusion detection is of great importance. For the shortcomings of depth insensitive and shadow interference of single image method, an intrusion detection method with binocular stereo vision is proposed to reconstruct the 3D scene for locating the objects and judging clearance intrusion. The binocular cameras are calibrated with Zhang Zhengyou's method. In order to improve the 3D reconstruction speed, a suspicious region is firstly determined by background difference method of a single camera's image sequences. The image rectification, stereo matching and 3D reconstruction process are only executed when there is a suspicious region. A transformation matrix from Camera Coordinate System(CCS) to Track Coordinate System(TCS) is computed with gauge constant and used to transfer the 3D point clouds into the TCS, then the 3D point clouds are used to calculate the object position and intrusion in TCS. The experiments in railway scene show that the position precision is better than 10mm. It is an effective way for clearance intrusion detection and can satisfy the requirement of railway application.

  13. Crossmodal Semantic Constraints on Visual Perception of Binocular Rivalry

    Yi-Chuan Chen

    2011-10-01

    Full Text Available Environments typically convey contextual information via several different sensory modalities. Here, we report a study designed to investigate the crossmodal semantic modulation of visual perception using the binocular rivalry paradigm. The participants viewed a dichoptic figure consisting of a bird and a car presented to each eye, while also listening to either a bird singing or car engine revving. Participants' dominant percepts were modulated by the presentation of a soundtrack associated with either bird or car, as compared to the presentation of a soundtrack irrelevant to both visual figures (tableware clattering together in a restaurant. No such crossmodal semantic effect was observed when the participants maintained an abstract semantic cue in memory. We then further demonstrate that crossmodal semantic modulation can be dissociated from the effects of high-level attentional control over the dichoptic figures and of low-level luminance contrast of the figures. In sum, we demonstrate a novel crossmodal effect in terms of crossmodal semantic congruency on binocular rivalry. This effect can be considered a perceptual grouping or contextual constraint on human visual awareness through mid-level crossmodal excitatory connections embedded in the multisensory semantic network.

  14. Separating monocular and binocular neural mechanisms mediating chromatic contextual interactions.

    D'Antona, Anthony D; Christiansen, Jens H; Shevell, Steven K

    2014-04-17

    When seen in isolation, a light that varies in chromaticity over time is perceived to oscillate in color. Perception of that same time-varying light may be altered by a surrounding light that is also temporally varying in chromaticity. The neural mechanisms that mediate these contextual interactions are the focus of this article. Observers viewed a central test stimulus that varied in chromaticity over time within a larger surround that also varied in chromaticity at the same temporal frequency. Center and surround were presented either to the same eye (monocular condition) or to opposite eyes (dichoptic condition) at the same frequency (3.125, 6.25, or 9.375 Hz). Relative phase between center and surround modulation was varied. In both the monocular and dichoptic conditions, the perceived modulation depth of the central light depended on the relative phase of the surround. A simple model implementing a linear combination of center and surround modulation fit the measurements well. At the lowest temporal frequency (3.125 Hz), the surround's influence was virtually identical for monocular and dichoptic conditions, suggesting that at this frequency, the surround's influence is mediated primarily by a binocular neural mechanism. At higher frequencies, the surround's influence was greater for the monocular condition than for the dichoptic condition, and this difference increased with temporal frequency. Our findings show that two separate neural mechanisms mediate chromatic contextual interactions: one binocular and dominant at lower temporal frequencies and the other monocular and dominant at higher frequencies (6-10 Hz).

  15. Moving toward queue operations at the Large Binocular Telescope Observatory

    Edwards, Michelle L.; Summers, Doug; Astier, Joseph; Suarez Sola, Igor; Veillet, Christian; Power, Jennifer; Cardwell, Andrew; Walsh, Shane

    2016-07-01

    The Large Binocular Telescope Observatory (LBTO), a joint scientific venture between the Instituto Nazionale di Astrofisica (INAF), LBT Beteiligungsgesellschaft (LBTB), University of Arizona, Ohio State University (OSU), and the Research Corporation, is one of the newest additions to the world's collection of large optical/infrared ground-based telescopes. With its unique, twin 8.4m mirror design providing a 22.8 meter interferometric baseline and the collecting area of an 11.8m telescope, LBT has a window of opportunity to exploit its singular status as the "first" of the next generation of Extremely Large Telescopes (ELTs). Prompted by urgency to maximize scientific output during this favorable interval, LBTO recently re-evaluated its operations model and developed a new strategy that augments classical observing with queue. Aided by trained observatory staff, queue mode will allow for flexible, multi-instrument observing responsive to site conditions. Our plan is to implement a staged rollout that will provide many of the benefits of queue observing sooner rather than later - with more bells and whistles coming in future stages. In this paper, we outline LBTO's new scientific model, focusing specifically on our "lean" resourcing and development, reuse and adaptation of existing software, challenges presented from our one-of-a-kind binocular operations, and lessons learned. We also outline further stages of development and our ultimate goals for queue.

  16. Remote landslide mapping using a laser rangefinder binocular and GPS

    M. Santangelo

    2010-12-01

    Full Text Available We tested a high-quality laser rangefinder binocular coupled with a GPS receiver connected to a Tablet PC running dedicated software to help recognize and map in the field recent rainfall-induced landslides. The system was tested in the period between March and April 2010, in the Monte Castello di Vibio area, Umbria, Central Italy. To test the equipment, we measured thirteen slope failures that were mapped previously during a visual reconnaissance field campaign conducted in February and March 2010. For reference, four slope failures were also mapped by walking the GPS receiver along the landslide perimeter. Comparison of the different mappings revealed that the geographical information obtained remotely for each landslide by the rangefinder binocular and GPS was comparable to the information obtained by walking the GPS around the landslide perimeter, and was superior to the information obtained through the visual reconnaissance mapping. Although our tests were not exhaustive, we maintain that the system is effective to map recent rainfall induced landslides in the field, and we foresee the possibility of using the same (or similar system to map landslides, and other geomorphological features, in other areas.

  17. Matching fundus photographs of classmates. An informal competition to promote learning and practice of direct ophthalmoscopy among medical students.

    Krohn, Jørgen; Kjersem, Bård; Høvding, Gunnar

    2014-05-01

    To present a new approach for teaching direct ophthalmoscopy to medical students. At the University of Bergen, four consecutive classes of fourth-year medical students complete a required 9-week ophthalmology course every year. In the present project, one fundus photograph was taken of each student. The photographs were randomly numbered, printed on A4 glossy photo paper, and displayed on the classroom wall. Each student was given a form to fill in the fellow students' names matching the number of the fundus photographs. They were encouraged to practise direct ophthalmoscopy on their classmates outside formal teaching hours. At the end of the course, they returned the filled-in forms, and those with the highest number of correct matches between the fundus photographs and fellow students received a reward. Between 2011 and 2013, 239 students completed their ophthalmology course. Of these, 220 students (92%) voluntarily participated in the project. The mean score was 70% correct matches between fundus photographs and fellow students (range 7 - 100%). The students' course evaluations were overall positive. We recommend the use of peer fundus photographs in the context of a learning competition as a simple, inexpensive, and effective way to improve teaching of direct ophthalmoscopy.

  18. A new form of rapid binocular plasticity in adult with amblyopia.

    Zhou, Jiawei; Thompson, Benjamin; Hess, Robert F

    2013-01-01

    Amblyopia is a neurological disorder of binocular vision affecting up to 3% of the population resulting from a disrupted period of early visual development. Recently, it has been shown that vision can be partially restored by intensive monocular or dichoptic training (4-6 weeks). This can occur even in adults owing to a residual degree of brain plasticity initiated by repetitive and successive sensory stimulation. Here we show that the binocular imbalance that characterizes amblyopia can be reduced by occluding the amblyopic eye with a translucent patch for as little as 2.5 hours, suggesting a degree of rapid binocular plasticity in adults resulting from a lack of sensory stimulation. The integrated binocular benefit is larger in our amblyopic group than in our normal control group. We propose that this rapid improvement in function, as a result of reduced sensory stimulation, represents a new form of plasticity operating at a binocular site.

  19. Use of focus measure operators for characterization of flood illumination adaptive optics ophthalmoscopy image quality.

    Alonso-Caneiro, David; Sampson, Danuta M; Chew, Avenell L; Collins, Michael J; Chen, Fred K

    2018-02-01

    Adaptive optics flood illumination ophthalmoscopy (AO-FIO) allows imaging of the cone photoreceptor in the living human retina. However, clinical interpretation of the AO-FIO image remains challenging due to suboptimal quality arising from residual uncorrected wavefront aberrations and rapid eye motion. An objective method of assessing image quality is necessary to determine whether an AO-FIO image is suitable for grading and diagnostic purpose. In this work, we explore the use of focus measure operators as a surrogate measure of AO-FIO image quality. A set of operators are tested on data sets acquired at different focal depths and different retinal locations from healthy volunteers. Our results demonstrate differences in focus measure operator performance in quantifying AO-FIO image quality. Further, we discuss the potential application of the selected focus operators in (i) selection of the best quality AO-FIO image from a series of images collected at the same retinal location and (ii) assessment of longitudinal changes in the diseased retina. Focus function could be incorporated into real-time AO-FIO image processing and provide an initial automated quality assessment during image acquisition or reading center grading.

  20. Towards simultaneous Talbot bands based optical coherence tomography and scanning laser ophthalmoscopy imaging.

    Marques, Manuel J; Bradu, Adrian; Podoleanu, Adrian Gh

    2014-05-01

    We report a Talbot bands-based optical coherence tomography (OCT) system capable of producing longitudinal B-scan OCT images and en-face scanning laser ophthalmoscopy (SLO) images of the human retina in-vivo. The OCT channel employs a broadband optical source and a spectrometer. A gap is created between the sample and reference beams while on their way towards the spectrometer's dispersive element to create Talbot bands. The spatial separation of the two beams facilitates collection by an SLO channel of optical power originating exclusively from the retina, deprived from any contribution from the reference beam. Three different modes of operation are presented, constrained by the minimum integration time of the camera used in the spectrometer and by the galvo-scanners' scanning rate: (i) a simultaneous acquisition mode over the two channels, useful for small size imaging, that conserves the pixel-to-pixel correspondence between them; (ii) a hybrid sequential mode, where the system switches itself between the two regimes and (iii) a sequential "on-demand" mode, where the system can be used in either OCT or SLO regimes for as long as required. The two sequential modes present varying degrees of trade-off between pixel-to-pixel correspondence and independent full control of parameters within each channel. Images of the optic nerve and fovea regions obtained in the simultaneous (i) and in the hybrid sequential mode (ii) are presented.

  1. Multimodal scanning laser ophthalmoscopy for image guided treatment of age-related macular degeneration

    Hammer, Daniel X.; Ferguson, R. D.; Patel, Ankit H.; Iftimia, Nicusor V.; Mujat, Mircea; Husain, Deeba

    2009-02-01

    Subretinal neovascular membranes (SRNM) are a deleterious complication of laser eye injury and retinal diseases such as age-related macular degeneration (AMD), choroiditis, and myopic retinopathy. Photodynamic therapy (PDT) and anti-vascular endothelial growth factor (VEGF) drugs are approved treatment methods. PDT acts by selective dye accumulation, activation by laser light, and disruption and clotting of the new leaky vessels. However, PDT surgery is currently not image-guided, nor does it proceed in an efficient or automated manner. This may contribute to the high rate of re-treatment. We have developed a multimodal scanning laser ophthalmoscope (SLO) for automated diagnosis and image-guided treatment of SRNMs associated with AMD. The system combines line scanning laser ophthalmoscopy (LSLO), fluorescein angiography (FA), indocyanine green angiography (ICGA), PDT laser delivery, and retinal tracking in a compact, efficient platform. This paper describes the system hardware and software design, performance characterization, and automated patient imaging and treatment session procedures and algorithms. Also, we present initial imaging and tracking measurements on normal subjects and automated lesion demarcation and sizing analysis of previously acquired angiograms. Future pre-clinical testing includes line scanning angiography and PDT treatment of AMD subjects. The automated acquisition procedure, enhanced and expedited data post-processing, and innovative image visualization and interpretation tools provided by the multimodal retinal imager may eventually aid in the diagnosis, treatment, and prognosis of AMD and other retinal diseases.

  2. Uniocular and binocular fields of rotation measures: Octopus versus Goldmann.

    Rowe, Fiona J; Hanif, Sahira

    2011-06-01

    To compare the range of ocular rotations measured by Octopus versus Goldmann perimetry. Forty subjects (20 controls and 20 patients with impaired ocular movements) were prospectively recruited, age range 21-83 years. Range of uniocular rotations was measured in six vectors corresponding to extraocular muscle actions: 0°, 67°, 141°, 180°, 216°, 293°. Fields of binocular single vision were assessed at 30° intervals. Vector measurements were utilised to calculate an area score for the field of uniocular rotations or binocular field of single vision. Two test speeds were used for Octopus testing: 3°/ and 10°/second. Test duration was two thirds quicker for Octopus 10°/second than for 3°/second stimulus speed, and slightly quicker for Goldmann. Mean area for control subjects for uniocular field was 7910.45 degrees(2) for Goldmann, 7032.14 for Octopus 3°/second and 7840.66 for Octopus 10°/second. Mean area for patient subjects of right uniocular field was 8567.21 degrees(2) for Goldmann, 5906.72 for Octopus 3°/second and 8806.44 for Octopus 10°/second. Mean area for left uniocular field was 8137.49 degrees(2) for Goldmann, 8127.9 for Octopus 3°/second and 8950.54 for Octopus 10°/second. Range of measured rotation was significantly larger for Octopus 10°/second speed. Our results suggest that the Octopus perimeter is an acceptable alternative method of assessment for uniocular ductions and binocular field of single vision. Speed of stimulus significantly alters test duration for Octopus perimetry. Comparisons of results from both perimeters show that quantitative measurements differ, although qualitatively the results are similar. Differences per mean vectors were less than 5° (within clinically accepted variances) for both controls and patients when comparing Goldmann to Octopus 10°/second speed. However, differences were almost 10° for the patient group when comparing Goldmann to Octopus 3°/second speed. Thus, speed of stimulus must be considered

  3. Contrast-balanced binocular treatment in children with deprivation amblyopia.

    Hamm, Lisa M; Chen, Zidong; Li, Jinrong; Dai, Shuan; Black, Joanna; Yuan, Junpeng; Yu, Minbin; Thompson, Benjamin

    2017-11-28

    Children with deprivation amblyopia due to childhood cataract have been excluded from much of the emerging research into amblyopia treatment. An investigation was conducted to determine whether contrast-balanced binocular treatment - a strategy currently being explored for children with anisometropic and strabismic amblyopia - may be effective in children with deprivation amblyopia. An unmasked, case-series design intended to assess proof of principle was employed. Eighteen children with deprivation amblyopia due to childhood cataracts (early bilateral n = 7, early unilateral n = 7, developmental n = 4), as well as 10 children with anisometropic (n = 8) or mixed anisometropic and strabismic amblyopia (n = 2) were prescribed one hour a day of treatment over a six-week period. Supervised treatment was available. Visual acuity, contrast sensitivity, global motion perception and interocular suppression were measured pre- and post-treatment. Visual acuity improvements occurred in the anisometropic/strabismic group (0.15 ± 0.05 logMAR, p = 0.014), but contrast sensitivity did not change. As a group, children with deprivation amblyopia had a smaller but statistically significant improvement in weaker eye visual acuity (0.09 ± 0.03 logMAR, p = 0.004), as well a significant improvement in weaker eye contrast sensitivity (p = 0.004). Subgroup analysis suggested that the children with early bilateral deprivation had the largest improvements, while children with early unilateral cataract did not improve. Interestingly, binocular contrast sensitivity also improved in children with early bilateral deprivation. Global motion perception improved for both subgroups with early visual deprivation, as well as children with anisometropic or mixed anisometropic/strabismic amblyopia. Interocular suppression improved for all subgroups except children with early unilateral deprivation. These data suggest that supervised contrast-balanced binocular

  4. 21 CFR 886.1380 - Diagnostic condensing lens.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic condensing lens. 886.1380 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1380 Diagnostic condensing lens. (a) Identification. A diagnostic condensing lens is a device used in binocular indirect ophthalmoscopy (a procedure...

  5. Contextual Cueing Effect in Spatial Layout Defined by Binocular Disparity

    Zhao, Guang; Zhuang, Qian; Ma, Jie; Tu, Shen; Liu, Qiang; Sun, Hong-jin

    2017-01-01

    Repeated visual context induces higher search efficiency, revealing a contextual cueing effect, which depends on the association between the target and its visual context. In this study, participants performed a visual search task where search items were presented with depth information defined by binocular disparity. When the 3-dimensional (3D) configurations were repeated over blocks, the contextual cueing effect was obtained (Experiment 1). When depth information was in chaos over repeated configurations, visual search was not facilitated and the contextual cueing effect largely crippled (Experiment 2). However, when we made the search items within a tiny random displacement in the 2-dimentional (2D) plane but maintained the depth information constant, the contextual cueing was preserved (Experiment 3). We concluded that the contextual cueing effect was robust in the context provided by 3D space with stereoscopic information, and more importantly, the visual system prioritized stereoscopic information in learning of spatial information when depth information was available. PMID:28912739

  6. A Novel Approach to Calibrating Multifunctional Binocular Stereovision Sensor

    Xue, T; Zhu, J G; Wu, B; Ye, S H

    2006-01-01

    We present a novel multifunctional binocular stereovision sensor for various threedimensional (3D) inspection tasks. It not only avoids the so-called correspondence problem of passive stereo vision, but also possesses the uniform mathematical model. We also propose a novel approach to estimating all the sensor parameters with free-position planar reference object. In this technique, the planar pattern can be moved freely by hand. All the camera intrinsic and extrinsic parameters with coefficient of lens radial and tangential distortion are estimated, and sensor parameters are calibrated based on the 3D measurement model and optimized with the feature point constraint algorithm using the same views in the camera calibration stage. The proposed approach greatly reduces the cost of the calibration equipment, and it is flexible and practical for the vision measurement. It shows that this method has high precision by experiment, and the sensor measured relative error of space length excels 0.3%

  7. Natural Tendency towards Beauty in Humans: Evidence from Binocular Rivalry.

    Mo, Ce; Xia, Tiansheng; Qin, Kaixin; Mo, Lei

    2016-01-01

    Although human preference for beauty is common and compelling in daily life, it remains unknown whether such preference is essentially subserved by social cognitive demands or natural tendency towards beauty encoded in the human mind intrinsically. Here we demonstrate experimentally that humans automatically exhibit preference for visual and moral beauty without explicit cognitive efforts. Using a binocular rivalry paradigm, we identified enhanced gender-independent perceptual dominance for physically attractive persons, and the results suggested universal preference for visual beauty based on perceivable forms. Moreover, we also identified perceptual dominance enhancement for characters associated with virtuous descriptions after controlling for facial attractiveness and vigilance-related attention effects, which suggested a similar implicit preference for moral beauty conveyed in prosocial behaviours. Our findings show that behavioural preference for beauty is driven by an inherent natural tendency towards beauty in humans rather than explicit social cognitive processes.

  8. Binocular diplopia in a tertiary hospital: Aetiology, diagnosis and treatment.

    Merino, P; Fuentes, D; Gómez de Liaño, P; Ordóñez, M A

    2017-12-01

    To study the causes, diagnosis and treatment in a case series of binocular diplopia. A retrospective chart review was performed on patients seen in the Diplopia Unit of a tertiary centre during a one-year period. Diplopia was classified as: acute≤1 month since onset; subacute (1-6 months); and chronic (>6 months). Resolution of diplopia was classified as: spontaneous if it disappeared without treatment, partial if the course was intermittent, and non-spontaneous if treatment was required. It was considered a good outcome when diplopia disappeared completely (with or without treatment), or when diplopia was intermittent without significantly affecting the quality of life. A total of 60 cases were included. The mean age was 58.65 years (60% female). An acute or subacute presentation was observed in 60% of the patients. The mean onset of diplopia was 82.97 weeks. The most frequent aetiology was ischaemic (45%). The most frequent diagnosis was sixth nerve palsy (38.3%), followed by decompensated strabismus (30%). Neuroimaging showed structural lesions in 17.7% of the patients. There was a spontaneous resolution in 28.3% of the cases, and there was a good outcome with disappearance of the diplopia in 53.3% at the end of the study. The most frequent causes of binocular diplopia were cranial nerve palsies, especially the sixth cranial nerve, followed by decompensated strabismus. Structural lesions in imaging tests were more than expected. Only one third of patients had a spontaneous resolution, and half of them did not have a good outcome despite of treatment. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Combining Motion-Induced Blindness with Binocular Rivalry

    K Jaworska

    2011-04-01

    Full Text Available Motion-induced blindness (MIB and binocular rivalry (BR are examples of multistable phenomena in which our perception varies despite constant retinal input. It has been suggested that both phenomena are related and share a common underlying mechanism. We tried to determine whether experimental manipulations of the target dot and the mask systematically affect MIB and BR in an experimental paradigm that can elicit both phenomena. Eighteen observers fixated the center of a split-screen stereo display that consisted of a distracter mask and a superimposed target dot with different colour (isoluminant Red/Green in corresponding peripheral areas of the left and right eye. Observers reported perceived colour and disappearance of the target dot by pressing and releasing corresponding keys. In a within-subjects design the mask was presented in rivalry or not—with orthogonal drift in the left and right eye or with the same drift in both eyes. In control conditions the mask remained stationary. In addition, the size of the target dot was varied (small, medium, and large. Our results suggest that MIB measured by normalized frequency and duration of target disappearance and BR measured by normalized frequency and duration of colour reversals of the target were both affected by motion in the mask. Surprisingly, binocular rivalry in the mask had only a small effect on BR of the target and virtually no effect on MIB. The overall pattern of normalized MIB and BR measures, however, differed across experimental conditions. In conclusion, the results show some degree of dissociation between MIB and BR. Further analyses will inform whether or not the two phenomena occur independently of each other.

  10. Origins of strabismus and loss of binocular vision

    Bui Quoc, Emmanuel; Milleret, Chantal

    2014-01-01

    Strabismus is a frequent ocular disorder that develops early in life in humans. As a general rule, it is characterized by a misalignment of the visual axes which most often appears during the critical period of visual development. However other characteristics of strabismus may vary greatly among subjects, for example, being convergent or divergent, horizontal or vertical, with variable angles of deviation. Binocular vision may also vary greatly. Our main goal here is to develop the idea that such “polymorphy” reflects a wide variety in the possible origins of strabismus. We propose that strabismus must be considered as possibly resulting from abnormal genetic and/or acquired factors, anatomical and/or functional abnormalities, in the sensory and/or the motor systems, both peripherally and/or in the brain itself. We shall particularly develop the possible “central” origins of strabismus. Indeed, we are convinced that it is time now to open this “black box” in order to move forward. All of this will be developed on the basis of both presently available data in literature (including most recent data) and our own experience. Both data in biology and medicine will be referred to. Our conclusions will hopefully help ophthalmologists to better understand strabismus and to develop new therapeutic strategies in the future. Presently, physicians eliminate or limit the negative effects of such pathology both on the development of the visual system and visual perception through the use of optical correction and, in some cases, extraocular muscle surgery. To better circumscribe the problem of the origins of strabismus, including at a cerebral level, may improve its management, in particular with respect to binocular vision, through innovating tools by treating the pathology at the source. PMID:25309358

  11. Indirection and computer security.

    Berg, Michael J.

    2011-09-01

    The discipline of computer science is built on indirection. David Wheeler famously said, 'All problems in computer science can be solved by another layer of indirection. But that usually will create another problem'. We propose that every computer security vulnerability is yet another problem created by the indirections in system designs and that focusing on the indirections involved is a better way to design, evaluate, and compare security solutions. We are not proposing that indirection be avoided when solving problems, but that understanding the relationships between indirections and vulnerabilities is key to securing computer systems. Using this perspective, we analyze common vulnerabilities that plague our computer systems, consider the effectiveness of currently available security solutions, and propose several new security solutions.

  12. Dynamic distance direct ophthalmoscopy, a novel technique to assess accommodation in children

    Mihir Kothari

    2012-01-01

    Full Text Available Aim: To describe and compare dynamic distance direct ophthalmoscopy (DDDO with dynamic retinoscopy (DR in assessment of accommodation in children. Materials and Methods: This prospective observational study had four components. Component 1: to understand the characteristic digital images of DDDO. Component 2: to compare DDDO with DR for detection of accommodative defects in children (1-16 years. Component 3: to compare DDDO with DR for the detection of completeness of pharmacologically induced cycloplegia in children (5-16 years and Component 4: to assess which one of the two techniques was more sensitive to detect onset of cycloplegia after instillation of 1% cyclopentolate eye drops. Results: Component 1: image analysis of DDDO on two subjects (7 years and 35 years demonstrated superior pupillary crescent that progressively disappeared with increasing accommodation. Concurrently an inferior crescent appeared that became bigger in size with increasing accommodation. Component 2: the prevalence of defects in accommodation was 3.3% (33/1000 children. Three had unilateral accommodation failure. Sensitivity of DDDO was 94%, specificity 100%, positive predictive value 100%, negative predictive value 99%, and clinical agreement (kappa 0.97. Component 3: in the detection of completeness of pharmacologically induced cycloplegia (n=30, the sensitivity of DDDO was 94%, specificity 96%, positive predictive value 97%, negative predictive value 93% and kappa 0.9. DR had two false positives. DDDO had one false negative. Component 4: DDDO detected onset of pharmacologically induced cycloplegia 5 min earlier than DR (n=5. Conclusion: DDDO is a novel, simple, clinical and reliable method to assess accommodation in young children. This test can assess the accommodative response of both eyes simultaneously.

  13. Multimodal ophthalmic imaging using spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography

    El-Haddad, Mohamed T.; Malone, Joseph D.; Li, Jianwei D.; Bozic, Ivan; Arquitola, Amber M.; Joos, Karen M.; Patel, Shriji N.; Tao, Yuankai K.

    2017-08-01

    Ophthalmic surgery involves manipulation of delicate, layered tissue structures on milli- to micrometer scales. Traditional surgical microscopes provide an inherently two-dimensional view of the surgical field with limited depth perception which precludes accurate depth-resolved visualization of these tissue layers, and limits the development of novel surgical techniques. We demonstrate multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography (SS-SESLO-OCT) to address current limitations of image-guided ophthalmic microsurgery. SS-SESLO-OCT provides inherently co-registered en face and cross-sectional field-of-views (FOVs) at a line rate of 400 kHz and >2 GPix/s throughput. We show in vivo imaging of the anterior segment and retinal fundus of a healthy volunteer, and preliminary results of multi-volumetric mosaicking for ultrawide-field retinal imaging with 90° FOV. Additionally, a scan-head was rapid-prototyped with a modular architecture which enabled integration of SS-SESLO-OCT with traditional surgical microscope and slit-lamp imaging optics. Ex vivo surgical maneuvers were simulated in cadaveric porcine eyes. The system throughput enabled volumetric acquisition at 10 volumes-per-second (vps) and allowed visualization of surgical dynamics in corneal sweeps, compressions, and dissections, and retinal sweeps, compressions, and elevations. SESLO en face images enabled simple real-time co-registration with the surgical microscope FOV, and OCT cross-sections provided depth-resolved visualization of instrument-tissue interactions. Finally, we demonstrate novel augmented-reality integration with the surgical view using segmentation overlays to aid surgical guidance. SS-SESLO-OCT may benefit clinical diagnostics by enabling aiming, registration, and mosaicking; and intraoperative imaging by allowing for real-time surgical feedback, instrument tracking, and overlays of computationally extracted biomarkers of disease.

  14. The fundus photo has met its match: optical coherence tomography and adaptive optics ophthalmoscopy are here to stay.

    Morgan, Jessica I W

    2016-05-01

    Over the past 25 years, optical coherence tomography (OCT) and adaptive optics (AO) ophthalmoscopy have revolutionised our ability to non-invasively observe the living retina. The purpose of this review is to highlight the techniques and human clinical applications of recent advances in OCT and adaptive optics scanning laser/light ophthalmoscopy (AOSLO) ophthalmic imaging. Optical coherence tomography retinal and optic nerve head (ONH) imaging technology allows high resolution in the axial direction resulting in cross-sectional visualisation of retinal and ONH lamination. Complementary AO ophthalmoscopy gives high resolution in the transverse direction resulting in en face visualisation of retinal cell mosaics. Innovative detection schemes applied to OCT and AOSLO technologies (such as spectral domain OCT, OCT angiography, confocal and non-confocal AOSLO, fluorescence, and AO-OCT) have enabled high contrast between retinal and ONH structures in three dimensions and have allowed in vivo retinal imaging to approach that of histological quality. In addition, both OCT and AOSLO have shown the capability to detect retinal reflectance changes in response to visual stimuli, paving the way for future studies to investigate objective biomarkers of visual function at the cellular level. Increasingly, these imaging techniques are being applied to clinical studies of the normal and diseased visual system. Optical coherence tomography and AOSLO technologies are capable of elucidating the structure and function of the retina and ONH noninvasively with unprecedented resolution and contrast. The techniques have proven their worth in both basic science and clinical applications and each will continue to be utilised in future studies for many years to come. © 2016 The Authors Ophthalmic & Physiological Optics © 2016 The College of Optometrists.

  15. Simultaneous in vivo imaging of melanin and lipofuscin in the retina with photoacoustic ophthalmoscopy and autofluorescence imaging

    Zhang, Xiangyang; Zhang, Hao F.; Puliafito, Carmen A.; Jiao, Shuliang

    2011-08-01

    We combined photoacoustic ophthalmoscopy (PAOM) with autofluorescence imaging for simultaneous in vivo imaging of dual molecular contrasts in the retina using a single light source. The dual molecular contrasts come from melanin and lipofuscin in the retinal pigment epithelium (RPE). Melanin and lipofuscin are two types of pigments and are believed to play opposite roles (protective versus exacerbate) in the RPE in the aging process. We have successfully imaged the retina of pigmented and albino rats at different ages. The experimental results showed that multimodal PAOM system can be a potentially powerful tool in the study of age-related degenerative retinal diseases.

  16. Monocular and binocular development in children with albinism, infantile nystagmus syndrome, and normal vision.

    Huurneman, Bianca; Boonstra, F Nienke

    2013-12-01

    To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (n = 16), children with infantile nystagmus syndrome (n = 10), and children with normal vision (n = 72). Interocular acuity differences and binocular summation ratios were compared between groups. Crowding ratios were calculated by dividing the single Landolt C decimal acuity with the crowded Landolt C decimal acuity mono- and binocularly. A linear regression analysis was conducted to investigate the contribution of 5 predictors to the monocular and binocular crowding ratio: nystagmus amplitude, nystagmus frequency, strabismus, astigmatism, and anisometropia. Crowding ratios were higher under mono- and binocular viewing conditions for children with infantile nystagmus syndrome than for children with normal vision. Children with albinism showed higher crowding ratios in their poorer eye and under binocular viewing conditions than children with normal vision. Children with albinism and children with infantile nystagmus syndrome showed larger interocular acuity differences than children with normal vision (0.1 logMAR in our clinical groups and 0.0 logMAR in children with normal vision). Binocular summation ratios did not differ between groups. Strabismus and nystagmus amplitude predicted the crowding ratio in the poorer eye (p = 0.015 and p = 0.005, respectively). The crowding ratio in the better eye showed a marginally significant relation with nystagmus frequency and depth of anisometropia (p = 0.082 and p = 0.070, respectively). The binocular crowding ratio was not predicted by any of the variables. Children with albinism and children with infantile nystagmus syndrome show larger interocular acuity differences than children with normal vision. Strabismus and nystagmus amplitude are significant predictors of the crowding ratio in the poorer eye.

  17. A new form of rapid binocular plasticity in adult with amblyopia

    Zhou, Jiawei; Thompson, Benjamin; Hess, Robert F.

    2013-01-01

    Amblyopia is a neurological disorder of binocular vision affecting up to 3% of the population resulting from a disrupted period of early visual development. Recently, it has been shown that vision can be partially restored by intensive monocular or dichoptic training (4?6 weeks). This can occur even in adults owing to a residual degree of brain plasticity initiated by repetitive and successive sensory stimulation. Here we show that the binocular imbalance that characterizes amblyopia can be r...

  18. Binocular treatment of amblyopia using videogames (BRAVO): study protocol for a randomised controlled trial

    Guo, Cindy X.; Babu, Raiju J.; Black, Joanna M.; Bobier, William R.; Lam, Carly S. Y.; Dai, Shuan; Gao, Tina Y.; Hess, Robert F.; Jenkins, Michelle; Jiang, Yannan; Kowal, Lionel; Parag, Varsha; South, Jayshree; Staffieri, Sandra Elfride; Walker, Natalie

    2016-01-01

    Background Amblyopia is a common neurodevelopmental disorder of vision that is characterised by visual impairment in one eye and compromised binocular visual function. Existing evidence-based treatments for children include patching the nonamblyopic eye to encourage use of the amblyopic eye. Currently there are no widely accepted treatments available for adults with amblyopia. The aim of this trial is to assess the efficacy of a new binocular, videogame-based treatment for amblyopia in older ...

  19. Tratamiento binocular de la ambliopía basado en la realidad virtual

    Yanet Cristina Díaz Núñez

    Full Text Available Aunque los tratamientos predominantes de la ambliopía son monoculares, estos tienen poca aceptación y baja efectividad en el restablecimiento de la combinación binocular. Numerosas evidencias apoyan la idea de que la ambliopía es en esencia un problema binocular y que la supresión juega un papel clave. En esta revisión se exponen dos estrategias para el tratamiento binocular de la ambliopía basado en la realidad virtual; la primera con el objetivo primario de mejorar la agudeza visual y la segunda con el propósito de mejorar las funciones binoculares a través de la reducción de la supresión. Este enfoque binocular expone al paciente a condiciones artificiales de visión con estímulos dicópticos en imágenes relacionadas. Los estudios clínicos realizados, tanto en niños como adultos, reportan mejorías de la agudeza visual y la estereopsia en un tiempo muy inferior al requerido por la oclusión. Los resultados clínicos sugieren que un enfoque binocular que combine ambas estrategias puede utilizarse como complemento de los tratamientos clásicos y como alternativa en adultos y niños con historial de tratamientos fracasados o rechazados.

  20. Development and matching of binocular orientation preference in mouse V1.

    Bhaumik, Basabi; Shah, Nishal P

    2014-01-01

    Eye-specific thalamic inputs converge in the primary visual cortex (V1) and form the basis of binocular vision. For normal binocular perceptions, such as depth and stereopsis, binocularly matched orientation preference between the two eyes is required. A critical period of binocular matching of orientation preference in mice during normal development is reported in literature. Using a reaction diffusion model we present the development of RF and orientation selectivity in mouse V1 and investigate the binocular orientation preference matching during the critical period. At the onset of the critical period the preferred orientations of the modeled cells are mostly mismatched in the two eyes and the mismatch decreases and reaches levels reported in juvenile mouse by the end of the critical period. At the end of critical period 39% of cells in binocular zone in our model cortex is orientation selective. In literature around 40% cortical cells are reported as orientation selective in mouse V1. The starting and the closing time for critical period determine the orientation preference alignment between the two eyes and orientation tuning in cortical cells. The absence of near neighbor interaction among cortical cells during the development of thalamo-cortical wiring causes a salt and pepper organization in the orientation preference map in mice. It also results in much lower % of orientation selective cells in mice as compared to ferrets and cats having organized orientation maps with pinwheels.

  1. Association between fine motor skills and binocular visual function in children with reading difficulties.

    Niechwiej-Szwedo, Ewa; Alramis, Fatimah; Christian, Lisa W

    2017-12-01

    Performance of fine motor skills (FMS) assessed by a clinical test battery has been associated with reading achievement in school-age children. However, the nature of this association remains to be established. The aim of this study was to assess FMS in children with reading difficulties using two experimental tasks, and to determine if performance is associated with reduced binocular function. We hypothesized that in comparison to an age- and sex-matched control group, children identified with reading difficulties will perform worse only on a motor task that has been shown to rely on binocular input. To test this hypothesis, motor performance was assessed using two tasks: bead-threading and peg-board in 19 children who were reading below expected grade and age-level. Binocular vision assessment included tests for stereoacuity, fusional vergence, amplitude of accommodation, and accommodative facility. In comparison to the control group, children with reading difficulties performed significantly worse on the bead-threading task. In contrast, performance on the peg-board task was similar in both groups. Accommodative facility was the only measure of binocular function significantly associated with motor performance. Findings from our exploratory study suggest that normal binocular vision may provide an important sensory input for the optimal development of FMS and reading. Given the small sample size tested in the current study, further investigation to assess the contribution of binocular vision to the development and performance of FMS and reading is warranted. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Development and Matching of Binocular Orientation Preference in Mouse V1

    Basabi eBhaumik

    2014-07-01

    Full Text Available Eye-specific thalamic inputs converge in the primary visual cortex (V1 and form the basis of binocular vision. For normal binocular perceptions, such as depth and stereopsis, binocularly matched orientation preference between the two eyes is required. A critical period of binocular matching of orientation preference in mice during normal development is reported in literature. Using a reaction diffusion model we present the development of RF and orientation selectivity in mouse V1 and investigate the binocular orientation preference matching during the critical period. At the onset of the critical period the preferred orientations of the modeled cells are mostly mismatched in the two eyes and the mismatch decreases and reaches levels reported in juvenile mouse by the end of the critical period. At the end of critical period 39% of cells in binocular zone in our model cortex is orientation selective. In literature around 40% cortical cells are reported as orientation selective in mouse V1. The starting and the closing time for critical period determine the orientation preference alignment between the two eyes and orientation tuning in cortical cells. The absence of near neighbor interaction among cortical cells during the development of thalmo-cortical wiring causes a salt and pepper organization in the orientation preference map in mice. It also results in much lower % of orientation selective cells in mice as compared to ferrets and cats having organized orientation maps with pinwheels.

  3. Psilocybin links binocular rivalry switch rate to attention and subjective arousal levels in humans.

    Carter, Olivia L; Hasler, Felix; Pettigrew, John D; Wallis, Guy M; Liu, Guang B; Vollenweider, Franz X

    2007-12-01

    Binocular rivalry occurs when different images are simultaneously presented to each eye. During continual viewing of this stimulus, the observer will experience repeated switches between visual awareness of the two images. Previous studies have suggested that a slow rate of perceptual switching may be associated with clinical and drug-induced psychosis. The objective of the study was to explore the proposed relationship between binocular rivalry switch rate and subjective changes in psychological state associated with 5-HT2A receptor activation. This study used psilocybin, the hallucinogen found naturally in Psilocybe mushrooms that had previously been found to induce psychosis-like symptoms via the 5-HT2A receptor. The effects of psilocybin (215 microg/kg) were considered alone and after pretreatment with the selective 5-HT2A antagonist ketanserin (50 mg) in ten healthy human subjects. Psilocybin significantly reduced the rate of binocular rivalry switching and increased the proportion of transitional/mixed percept experience. Pretreatment with ketanserin blocked the majority of psilocybin's "positive" psychosis-like hallucinogenic symptoms. However, ketanserin had no influence on either the psilocybin-induced slowing of binocular rivalry or the drug's "negative-type symptoms" associated with reduced arousal and vigilance. Together, these findings link changes in binocular rivalry switching rate to subjective levels of arousal and attention. In addition, it suggests that psilocybin's effect on binocular rivalry is unlikely to be mediated by the 5-HT2A receptor.

  4. An overview of instrumentation for the Large Binocular Telescope

    Wagner, R. Mark

    2012-09-01

    An overview of instrumentation for the Large Binocular Telescope (LBT) is presented. Optical instrumentation includes the Large Binocular Camera (LBC), a pair of wide-field (27' x 27') mosaic CCD imagers at the prime focus, and the Multi-Object Double Spectrograph (MODS), a pair of dual-beam blue-red optimized long-slit spectrographs mounted at the left and right direct F/15 Gregorian foci incorporating multiple slit masks for multi-object spectroscopy over a 6' field and spectral resolutions of up to 2000. Infrared instrumentation includes the LBT Near-IR Spectroscopic Utility with Camera and Integral Field Unit for Extragalactic Research (LUCI), a modular near-infrared (0.9-2.5 μm) imager and spectrograph pair mounted at the left and right front bent F/15 Gregorian foci and designed for seeing-limited (FOV: 4' × 4') imaging, long-slit spectroscopy, and multiobject spectroscopy utilizing cooled slit masks and diffraction limited (FOV: 0'.5 × 0'.5) imaging and long-slit spectroscopy. Strategic instruments under development that can utilize the full 23-m baseline of the LBT include an interferometric cryogenic beam combiner with near-infrared and thermal-infrared instruments for Fizeau imaging and nulling interferometry (LBTI) and an optical bench near-infrared beam combiner utilizing multi-conjugate adaptive optics for high angular resolution and sensitivity (LINC-NIRVANA). LBTI is currently undergoing commissioning on the LBT and utilizing the installed adaptive secondary mirrors in both single- sided and two-sided beam combination modes. In addition, a fiber-fed bench spectrograph (PEPSI) capable of ultra high resolution spectroscopy and spectropolarimetry (R = 40,000-300,000) will be available as a principal investigator instrument. Over the past four years the LBC pair, LUCI1, and MODS1 have been commissioned and are now scheduled for routine partner science observations. The delivery of both LUCI2 and MODS2 is anticipated before the end of 2012. The

  5. A buyer's and user's guide to astronomical telescopes and binoculars

    Mullaney, James

    2014-01-01

    Amateur astronomers of all skill levels are always contemplating their next telescope, and this book points the way to the most suitable instruments. Similarly, those who are buying their first telescopes – and these days not necessarily a low-cost one – will be able to compare and contrast different types and manufacturers. This revised new guide provides an extensive overview of binoculars and telescopes. It includes detailed up-to-date information on sources, selection and use of virtually every major type, brand, and model on today’s market, a truly invaluable treasure-trove of information and helpful advice for all amateur astronomers. Originally written in 2006, much of the first edition is inevitably now out of date, as equipment advances and manufacturers come and go. This second edition not only updates all the existing sections but adds two new ones: Astro-imaging and Professional-Amateur collaboration. Thanks to the rapid and amazing developments that have been made in digital cameras it is...

  6. Binocular depth processing in the ventral visual pathway.

    Verhoef, Bram-Ernst; Vogels, Rufin; Janssen, Peter

    2016-06-19

    One of the most powerful forms of depth perception capitalizes on the small relative displacements, or binocular disparities, in the images projected onto each eye. The brain employs these disparities to facilitate various computations, including sensori-motor transformations (reaching, grasping), scene segmentation and object recognition. In accordance with these different functions, disparity activates a large number of regions in the brain of both humans and monkeys. Here, we review how disparity processing evolves along different regions of the ventral visual pathway of macaques, emphasizing research based on both correlational and causal techniques. We will discuss the progression in the ventral pathway from a basic absolute disparity representation to a more complex three-dimensional shape code. We will show that, in the course of this evolution, the underlying neuronal activity becomes progressively more bound to the global perceptual experience. We argue that these observations most probably extend beyond disparity processing per se, and pertain to object processing in the ventral pathway in general. We conclude by posing some important unresolved questions whose answers may significantly advance the field, and broaden its scope.This article is part of the themed issue 'Vision in our three-dimensional world'. © 2016 The Author(s).

  7. Synchronization of binocular motion parameters optoelectronic measurement system

    Zhang, Lingfei; Ye, Dong; Che, Rensheng; Chen, Gang

    2008-10-01

    The synchronization between high-speed digital cameras and computers is very important for the binocular vision system based on light-weighted passive IR reflective markers and IR LED array PCB board, which is often used to measure the 3-D motion parameters of a rocket motor. In order to solve this problem, a comparison on the existing approaches to camera synchronization in the published literature was conducted. The advantages and disadvantages of the currently used methods were illustrated and their suitable applications were discussed. A new method, which uses self-made hardware resetting camera and software triggering image acquisition board, is provided. The self-made hardware is used to send TTL signal to two image acquisition boards one time per second. The TTL signal is used to reset two cameras and two image acquisition boards as PRIN signal, and then two image acquisition boards send same EXSYNC signal to two cameras. In this way, two cameras can be synchronized to exposure and capture images in the mean time. The test results indicated that the new approach designed in this paper can meet the demand of image acquisition at a speed of 200f/s, whose synchronization accuracy is up to micro second.

  8. Temporal Integration of Auditory Stimulation and Binocular Disparity Signals

    Marina Zannoli

    2011-10-01

    Full Text Available Several studies using visual objects defined by luminance have reported that the auditory event must be presented 30 to 40 ms after the visual stimulus to perceive audiovisual synchrony. In the present study, we used visual objects defined only by their binocular disparity. We measured the optimal latency between visual and auditory stimuli for the perception of synchrony using a method introduced by Moutoussis & Zeki (1997. Visual stimuli were defined either by luminance and disparity or by disparity only. They moved either back and forth between 6 and 12 arcmin or from left to right at a constant disparity of 9 arcmin. This visual modulation was presented together with an amplitude-modulated 500 Hz tone. Both modulations were sinusoidal (frequency: 0.7 Hz. We found no difference between 2D and 3D motion for luminance stimuli: a 40 ms auditory lag was necessary for perceived synchrony. Surprisingly, even though stereopsis is often thought to be slow, we found a similar optimal latency in the disparity 3D motion condition (55 ms. However, when participants had to judge simultaneity for disparity 2D motion stimuli, it led to larger latencies (170 ms, suggesting that stereo motion detectors are poorly suited to track 2D motion.

  9. An ancient explanation of presbyopia based on binocular vision.

    Barbero, Sergio

    2014-06-01

    Presbyopia, understood as the age-related loss of ability to clearly see near objects, was known to ancient Greeks. However, few references to it can be found in ancient manuscripts. A relevant discussion on presbyopia appears in a book called Symposiacs written by Lucius Mestrius Plutarchus around 100 A.C. In this work, Plutarch provided four explanations of presbyopia, associated with different theories of vision. One of the explanations is particularly interesting as it is based on a binocular theory of vision. In this theory, vision is produced when visual rays, emanating from the eyes, form visual cones that impinge on the objects to be seen. Visual rays coming from old people's eyes, it was supposed, are weaker than those from younger people's eyes; so the theory, to be logically coherent, implies that this effect is compensated by the increase in light intensity due to the overlapping, at a certain distance, of the visual cones coming from both eyes. Thus, it benefits the reader to move the reading text further away from the eyes in order to increase the fusion area of both visual cones. The historical hypothesis taking into consideration that the astronomer Hipparchus of Nicaea was the source of Plutarch's explanation of the theory is discussed. © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  10. Early laser operations at the Large Binocular Telescope Observatory

    Rahmer, Gustavo; Lefebvre, Michael; Christou, Julian; Raab, Walfried; Rabien, Sebastian; Ziegleder, Julian; Borelli, José L.; Gässler, Wolfgang

    2014-08-01

    ARGOS is the GLAO (Ground-Layer Adaptive Optics) Rayleigh-based LGS (Laser Guide Star) facility for the Large Binocular Telescope Observatory (LBTO). It is dedicated for observations with LUCI1 and LUCI2, LBTO's pair of NIR imagers and multi-object spectrographs. The system projects three laser beams from the back of each of the two secondary mirror units, which create two constellations circumscribed on circles of 2 arcmin radius with 120 degree spacing. Each of the six Nd:YAG lasers provides a beam of green (532nm) pulses at a rate of 10kHz with a power of 14W to 18W. We achieved first on-sky propagation on the night of November 5, 2013, and commissioning of the full system will take place during 2014. We present the initial results of laser operations at the observatory, including safety procedures and the required coordination with external agencies (FAA, Space Command, and Military Airspace Manager). We also describe our operational procedures and report on our experiences with aircraft spotters. Future plans for safer and more efficient aircraft monitoring and detection are discussed.

  11. EXO-ZODI MODELING FOR THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    Kennedy, Grant M.; Wyatt, Mark C.; Panić, Olja; Shannon, Andrew [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Bailey, Vanessa; Defrère, Denis; Hinz, Philip M.; Rieke, George H.; Skemer, Andrew J.; Su, Katherine Y. L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Bryden, Geoffrey; Mennesson, Bertrand; Morales, Farisa; Serabyn, Eugene [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Danchi, William C.; Roberge, Aki; Stapelfeldt, Karl R. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics, Code 667, Greenbelt, MD 20771 (United States); Haniff, Chris [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Lebreton, Jérémy [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Millan-Gabet, Rafael [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); and others

    2015-02-01

    Habitable zone dust levels are a key unknown that must be understood to ensure the success of future space missions to image Earth analogs around nearby stars. Current detection limits are several orders of magnitude above the level of the solar system's zodiacal cloud, so characterization of the brightness distribution of exo-zodi down to much fainter levels is needed. To this end, the Large Binocular Telescope Interferometer (LBTI) will detect thermal emission from habitable zone exo-zodi a few times brighter than solar system levels. Here we present a modeling framework for interpreting LBTI observations, which yields dust levels from detections and upper limits that are then converted into predictions and upper limits for the scattered light surface brightness. We apply this model to the HOSTS survey sample of nearby stars; assuming a null depth uncertainty of 10{sup –4} the LBTI will be sensitive to dust a few times above the solar system level around Sun-like stars, and to even lower dust levels for more massive stars.

  12. Bubble behavior characteristics based on virtual binocular stereo vision

    Xue, Ting; Xu, Ling-shuang; Zhang, Shang-zhen

    2018-01-01

    The three-dimensional (3D) behavior characteristics of bubble rising in gas-liquid two-phase flow are of great importance to study bubbly flow mechanism and guide engineering practice. Based on the dual-perspective imaging of virtual binocular stereo vision, the 3D behavior characteristics of bubbles in gas-liquid two-phase flow are studied in detail, which effectively increases the projection information of bubbles to acquire more accurate behavior features. In this paper, the variations of bubble equivalent diameter, volume, velocity and trajectory in the rising process are estimated, and the factors affecting bubble behavior characteristics are analyzed. It is shown that the method is real-time and valid, the equivalent diameter of the rising bubble in the stagnant water is periodically changed, and the crests and troughs in the equivalent diameter curve appear alternately. The bubble behavior characteristics as well as the spiral amplitude are affected by the orifice diameter and the gas volume flow.

  13. Bilateral symmetry in vision and influence of ocular surgical procedures on binocular vision: A topical review

    Samuel Arba Mosquera

    2016-10-01

    Full Text Available We analyze the role of bilateral symmetry in enhancing binocular visual ability in human eyes, and further explore how efficiently bilateral symmetry is preserved in different ocular surgical procedures. The inclusion criterion for this review was strict relevance to the clinical questions under research. Enantiomorphism has been reported in lower order aberrations, higher order aberrations and cone directionality. When contrast differs in the two eyes, binocular acuity is better than monocular acuity of the eye that receives higher contrast. Anisometropia has an uncommon occurrence in large populations. Anisometropia seen in infancy and childhood is transitory and of little consequence for the visual acuity. Binocular summation of contrast signals declines with age, independent of inter-ocular differences. The symmetric associations between the right and left eye could be explained by the symmetry in pupil offset and visual axis which is always nasal in both eyes. Binocular summation mitigates poor visual performance under low luminance conditions and strong inter-ocular disparity detrimentally affects binocular summation. Considerable symmetry of response exists in fellow eyes of patients undergoing myopic PRK and LASIK, however the method to determine whether or not symmetry is maintained consist of comparing individual terms in a variety of ad hoc ways both before and after the refractive surgery, ignoring the fact that retinal image quality for any individual is based on the sum of all terms. The analysis of bilateral symmetry should be related to the patients’ binocular vision status. The role of aberrations in monocular and binocular vision needs further investigation.

  14. Perceptual relearning of binocular fusion after hypoxic brain damage: four controlled single-case treatment studies.

    Schaadt, Anna-Katharina; Schmidt, Lena; Kuhn, Caroline; Summ, Miriam; Adams, Michaela; Garbacenkaite, Ruta; Leonhardt, Eva; Reinhart, Stefan; Kerkhoff, Georg

    2014-05-01

    Hypoxic brain damage is characterized by widespread, diffuse-disseminated brain lesions, which may cause severe disturbances in binocular vision, leading to diplopia and loss of stereopsis, for which no evaluated treatment is currently available. The study evaluated the effects of a novel binocular vision treatment designed to improve binocular fusion and stereopsis as well as to reduce diplopia in patients with cerebral hypoxia. Four patients with severely reduced convergent fusion, stereopsis, and reading duration due to hypoxic brain damage were treated in a single-subject baseline design, with three baseline assessments before treatment to control for spontaneous recovery (pretherapy), an assessment immediately after a treatment period of 6 weeks (posttherapy), and two follow-up tests 3 and 6 months after treatment to assess stability of improvements. Patients received a novel fusion and dichoptic training using 3 different devices designed to slowly increase fusional and disparity angle. After the treatment, all 4 patients improved significantly in binocular fusion, subjective reading duration until diplopia emerged, and 2 of 4 patients improved significantly in local stereopsis. No significant changes were observed during the pretherapy baseline period and the follow-up period, thus ruling out spontaneous recovery and demonstrating long-term stability of treatment effects. This proof-of-principle study indicates a substantial treatment-induced plasticity after hypoxia in the relearning of binocular vision and offers a viable treatment option. Moreover, it provides new hope and direction for the development of effective rehabilitation strategies to treat neurovisual deficits resulting from hypoxic brain damage.

  15. Analysis on detection accuracy of binocular photoelectric instrument optical axis parallelism digital calibration instrument

    Ying, Jia-ju; Yin, Jian-ling; Wu, Dong-sheng; Liu, Jie; Chen, Yu-dan

    2017-11-01

    Low-light level night vision device and thermal infrared imaging binocular photoelectric instrument are used widely. The maladjustment of binocular instrument ocular axises parallelism will cause the observer the symptom such as dizziness, nausea, when use for a long time. Binocular photoelectric equipment digital calibration instrument is developed for detecting ocular axises parallelism. And the quantitative value of optical axis deviation can be quantitatively measured. As a testing instrument, the precision must be much higher than the standard of test instrument. Analyzes the factors that influence the accuracy of detection. Factors exist in each testing process link which affect the precision of the detecting instrument. They can be divided into two categories, one category is factors which directly affect the position of reticle image, the other category is factors which affect the calculation the center of reticle image. And the Synthesize error is calculated out. And further distribute the errors reasonably to ensure the accuracy of calibration instruments.

  16. An assembly system based on industrial robot with binocular stereo vision

    Tang, Hong; Xiao, Nanfeng

    2017-01-01

    This paper proposes an electronic part and component assembly system based on an industrial robot with binocular stereo vision. Firstly, binocular stereo vision with a visual attention mechanism model is used to get quickly the image regions which contain the electronic parts and components. Secondly, a deep neural network is adopted to recognize the features of the electronic parts and components. Thirdly, in order to control the end-effector of the industrial robot to grasp the electronic parts and components, a genetic algorithm (GA) is proposed to compute the transition matrix and the inverse kinematics of the industrial robot (end-effector), which plays a key role in bridging the binocular stereo vision and the industrial robot. Finally, the proposed assembly system is tested in LED component assembly experiments, and the results denote that it has high efficiency and good applicability.

  17. Research on three-dimensional reconstruction method based on binocular vision

    Li, Jinlin; Wang, Zhihui; Wang, Minjun

    2018-03-01

    As the hot and difficult issue in computer vision, binocular stereo vision is an important form of computer vision,which has a broad application prospects in many computer vision fields,such as aerial mapping,vision navigation,motion analysis and industrial inspection etc.In this paper, a research is done into binocular stereo camera calibration, image feature extraction and stereo matching. In the binocular stereo camera calibration module, the internal parameters of a single camera are obtained by using the checkerboard lattice of zhang zhengyou the field of image feature extraction and stereo matching, adopted the SURF operator in the local feature operator and the SGBM algorithm in the global matching algorithm are used respectively, and the performance are compared. After completed the feature points matching, we can build the corresponding between matching points and the 3D object points using the camera parameters which are calibrated, which means the 3D information.

  18. Efficacy of vision therapy in children with learning disability and associated binocular vision anomalies.

    Hussaindeen, Jameel Rizwana; Shah, Prerana; Ramani, Krishna Kumar; Ramanujan, Lalitha

    To report the frequency of binocular vision (BV) anomalies in children with specific learning disorders (SLD) and to assess the efficacy of vision therapy (VT) in children with a non-strabismic binocular vision anomaly (NSBVA). The study was carried out at a centre for learning disability (LD). Comprehensive eye examination and binocular vision assessment was carried out for 94 children (mean (SD) age: 15 (2.2) years) diagnosed with specific learning disorder. BV assessment was done for children with best corrected visual acuity of ≥6/9 - N6, cooperative for examination and free from any ocular pathology. For children with a diagnosis of NSBVA (n=46), 24 children were randomized to VT and no intervention was provided to the other 22 children who served as experimental controls. At the end of 10 sessions of vision therapy, BV assessment was performed for both the intervention and non-intervention groups. Binocular vision anomalies were found in 59 children (62.8%) among which 22% (n=13) had strabismic binocular vision anomalies (SBVA) and 78% (n=46) had a NSBVA. Accommodative infacility (AIF) was the commonest of the NSBVA and found in 67%, followed by convergence insufficiency (CI) in 25%. Post-vision therapy, the intervention group showed significant improvement in all the BV parameters (Wilcoxon signed rank test, p<0.05) except negative fusional vergence. Children with specific learning disorders have a high frequency of binocular vision disorders and vision therapy plays a significant role in improving the BV parameters. Children with SLD should be screened for BV anomalies as it could potentially be an added hindrance to the reading difficulty in this special population. Copyright © 2017 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  19. Method used to test the imaging consistency of binocular camera's left-right optical system

    Liu, Meiying; Wang, Hu; Liu, Jie; Xue, Yaoke; Yang, Shaodong; Zhao, Hui

    2016-09-01

    To binocular camera, the consistency of optical parameters of the left and the right optical system is an important factor that will influence the overall imaging consistency. In conventional testing procedure of optical system, there lacks specifications suitable for evaluating imaging consistency. In this paper, considering the special requirements of binocular optical imaging system, a method used to measure the imaging consistency of binocular camera is presented. Based on this method, a measurement system which is composed of an integrating sphere, a rotary table and a CMOS camera has been established. First, let the left and the right optical system capture images in normal exposure time under the same condition. Second, a contour image is obtained based on the multiple threshold segmentation result and the boundary is determined using the slope of contour lines near the pseudo-contour line. Third, the constraint of gray level based on the corresponding coordinates of left-right images is established and the imaging consistency could be evaluated through standard deviation σ of the imaging grayscale difference D (x, y) between the left and right optical system. The experiments demonstrate that the method is suitable for carrying out the imaging consistency testing for binocular camera. When the standard deviation 3σ distribution of imaging gray difference D (x, y) between the left and right optical system of the binocular camera does not exceed 5%, it is believed that the design requirements have been achieved. This method could be used effectively and paves the way for the imaging consistency testing of the binocular camera.

  20. The effect of Bangerter filters on binocular function in observers with amblyopia.

    Chen, Zidong; Li, Jinrong; Thompson, Benjamin; Deng, Daming; Yuan, Junpeng; Chan, Lily; Hess, Robert F; Yu, Minbin

    2014-10-28

    We assessed whether partial occlusion of the nonamblyopic eye with Bangerter filters can immediately reduce suppression and promote binocular summation of contrast in observers with amblyopia. In Experiment 1, suppression was measured for 22 observers (mean age, 20 years; range, 14-32 years; 10 females) with strabismic or anisometropic amblyopia and 10 controls using our previously established "balance point" protocol. Measurements were made at baseline and with 0.6-, 0.4-, and 0.2-strength Bangerter filters placed over the nonamblyopic/dominant eye. In Experiment 2, psychophysical measurements of contrast sensitivity were made under binocular and monocular viewing conditions for 25 observers with anisometropic amblyopia (mean age, 17 years; range, 11-28 years; 14 females) and 22 controls (mean age, 24 years; range, 22-27; 12 female). Measurements were made at baseline, and with 0.4- and 0.2-strength Bangerter filters placed over the nonamblyopic/dominant eye. Binocular summation ratios (BSRs) were calculated at baseline and with Bangerter filters in place. Experiment 1: Bangerter filters reduced suppression in observers with amblyopia and induced suppression in controls (P = 0.025). The 0.2-strength filter eliminated suppression in observers with amblyopia and this was not a visual acuity effect. Experiment 2: Bangerter filters were able to induce normal levels of binocular contrast summation in the group of observers with anisometropic amblyopia for a stimulus with a spatial frequency of 3 cycles per degree (cpd, P = 0.006). The filters reduced binocular summation in controls. Bangerter filters can immediately reduce suppression and promote binocular summation for mid/low spatial frequencies in observers with amblyopia. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  1. Is there any evidence for the validity of diagnostic criteria used for accommodative and nonstrabismic binocular dysfunctions?

    Pilar Cacho-Martínez

    2014-01-01

    Conclusions: Scientific literature reveals differences between authors according to diagnostic criteria for accommodative and nonstrabismic binocular dysfunctions. Diagnostic accuracy studies show that there is only certain evidence for accommodative conditions. For binocular anomalies there is only evidence about a validated questionnaire for convergence insufficiency with no data of diagnostic accuracy.

  2. Visión binocular : diagnóstico y tratamiento

    Borràs García, M. Rosa

    1996-01-01

    Este libro está dirigido a todos los profesionales del campo de la optometría que quieran profundizar en la visión binocular. También está indicado para los alumnos de tercer curso de Optometría, tanto en asignaturas troncales como optativas. Sus contenidos están divididos en capítulos que pueden ser leídos de forma independiente, aunque es recomendable comprender el presente texto como una unidad. Su estructura abarca desde las disfunciones binoculares más frecuentes al estrabismo, la amblio...

  3. No-reference stereoscopic image quality measurement based on generalized local ternary patterns of binocular energy response

    Zhou, Wujie; Yu, Lu

    2015-01-01

    Perceptual no-reference (NR) quality measurement of stereoscopic images has become a challenging issue in three-dimensional (3D) imaging fields. In this article, we propose an efficient binocular quality-aware features extraction scheme, namely generalized local ternary patterns (GLTP) of binocular energy response, for general-purpose NR stereoscopic image quality measurement (SIQM). More specifically, we first construct the binocular energy response of a distorted stereoscopic image with different stimuli of amplitude and phase shifts. Then, the binocular quality-aware features are generated from the GLTP of the binocular energy response. Finally, these features are mapped to the subjective quality score of the distorted stereoscopic image by using support vector regression. Experiments on two publicly available 3D databases confirm the effectiveness of the proposed metric compared with the state-of-the-art full reference and NR metrics. (paper)

  4. Pedal indirect lymphangiography

    Lee, Kil Woo; Hong, Myung Sun; Kim, In Jae

    1994-01-01

    Recently, indirect lymphangiography has been developed as a relatively good and noninvasive imaging modality of the lymphatic system at extremities. But the disadvantage of the indirect lymphangiography is a low contrast ratio between the surrounding tissues and the contrast media in lymphatic vessels, because dimeric nonionic contrast media is water soluble and diluted in the proximal leg lymphatic vessels. We could have relatively better image than previously published images for the leg lymphatic system, when we injected contrast media with adequate high pressure in intradermal space of the interdigital areas at the foot dorsum. So, we would like to report the results. We could study all 9 lymphedemas(primary: 6, secondary: 3) from April 1990 to May 1993 on outpatient base. They were diagnosed as lymphedema clinically and radiologically. Ten ml of dimeric nonionic aget, iotrolan(Isovist 300) was injected into intradermal space with five 30-gauge needles. The injection speed was more than 0.2 ml/min. We have done one side pedal lymphangiogram in 30 minutes. The evaluation of the anterior superficial lymphatics was according to the criteria of the Weissleder. The results were as follows: 1. All lymphatic vessels from foot to inguinal area could be visualized. 2. Two or three inferior inguinal lymph nodes could be visualized about 42%. 3. The most common abnormal finding of the lymphedma was the neovascularization of the lymphatics on indirect pedal lymphangiogram. If we use adequate technique relatively high pressure injection, correct intradermal needle insertion, adequate soft tissue exposure technique indirect lymphangiography is considered to be a safe and noninvasive imaging modality for the evaluation of the lymphedema of lower extremity lymphatics including inferior inguinal lymph nodes

  5. Avian binocular vision: It's not just about what birds can see, it's also about what they can't.

    Luke P Tyrrell

    Full Text Available With the exception of primates, most vertebrates have laterally placed eyes. Binocular vision in vertebrates has been implicated in several functions, including depth perception, contrast discrimination, etc. However, the blind area in front of the head that is proximal to the binocular visual field is often neglected. This anterior blind area is important when discussing the evolution of binocular vision because its relative length is inversely correlated with the width of the binocular field. Therefore, species with wider binocular fields also have shorter anterior blind areas and objects along the mid-sagittal plane can be imaged at closer distances. Additionally, the anterior blind area is of functional significance for birds because the beak falls within this blind area. We tested for the first time some specific predictions about the functional role of the anterior blind area in birds controlling for phylogenetic effects. We used published data on visual field configuration in 40 species of birds and measured beak and skull parameters from museum specimens. We found that birds with proportionally longer beaks have longer anterior blind areas and thus narrower binocular fields. This result suggests that the anterior blind area and beak visibility do play a role in shaping binocular fields, and that binocular field width is not solely determined by the need for stereoscopic vision. In visually guided foragers, the ability to see the beak-and how much of the beak can be seen-varies predictably with foraging habits. For example, fish- and insect-eating specialists can see more of their own beak than birds eating immobile food can. But in non-visually guided foragers, there is no consistent relationship between the beak and anterior blind area. We discuss different strategies-wide binocular fields, large eye movements, and long beaks-that minimize the potential negative effects of the anterior blind area. Overall, we argue that there is more to

  6. Prevalence of non-strabismic anomalies of binocular vision in Tamil Nadu: report 2 of BAND study.

    Hussaindeen, Jameel Rizwana; Rakshit, Archayeeta; Singh, Neeraj Kumar; George, Ronnie; Swaminathan, Meenakshi; Kapur, Suman; Scheiman, Mitchell; Ramani, Krishna Kumar

    2017-11-01

    Population-based studies on the prevalence of non-strabismic anomalies of binocular vision in ethnic Indians are more than two decades old. Based on indigenous normative data, the BAND (Binocular Vision Anomalies and Normative Data) study aims to report the prevalence of non-strabismic anomalies of binocular vision among school children in rural and urban Tamil Nadu. This population-based, cross-sectional study was designed to estimate the prevalence of non-strabismic anomalies of binocular vision in the rural and urban population of Tamil Nadu. In four schools, two each in rural and urban arms, 920 children in the age range of seven to 17 years were included in the study. Comprehensive binocular vision assessment was done for all children including evaluation of vergence and accommodative systems. In the first phase of the study, normative data of parameters of binocular vision were assessed followed by prevalence estimates of non-strabismic anomalies of binocular vision. The mean and standard deviation of the age of the sample were 12.7 ± 2.7 years. The prevalence of non-strabismic anomalies of binocular vision in the urban and rural arms was found to be 31.5 and 29.6 per cent, respectively. Convergence insufficiency was the most prevalent (16.5 and 17.6 per cent in the urban and rural arms, respectively) among all the types of non-strabismic anomalies of binocular vision. There was no gender predilection and no statistically significant differences were observed between the rural and urban arms in the prevalence of non-strabismic anomalies of binocular vision (Z-test, p > 0.05). The prevalence of non-strabismic anomalies of binocular vision was found to be higher in the 13 to 17 years age group (36.2 per cent) compared to seven to 12 years (25.1 per cent) (Z-test, p < 0.05). Non-strabismic binocular vision anomalies are highly prevalent among school children and the prevalence increases with age. With increasing near visual demands in the higher

  7. Quantitative visual fields under binocular viewing conditions in primary and consecutive divergent strabismus

    Joosse, M. V.; Simonsz, H. J.; van Minderhout, E. M.; Mulder, P. G.; de Jong, P. T.

    1999-01-01

    Although there have been a number of studies on the size of the suppression scotoma in divergent strabismus, there have been no reports on the full extent (i.e. size as well as depth) of this scotoma. Binocular static perimetry was used to measure suppression scotomas in five patients with primary

  8. Efficacy of vision therapy in children with learning disability and associated binocular vision anomalies

    Jameel Rizwana Hussaindeen

    2018-01-01

    Conclusion: Children with specific learning disorders have a high frequency of binocular vision disorders and vision therapy plays a significant role in improving the BV parameters. Children with SLD should be screened for BV anomalies as it could potentially be an added hindrance to the reading difficulty in this special population.

  9. Monocular and binocular development in children with albinism, infantile nystagmus syndrome and normal vision

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (n = 16), children with infantile nystagmus syndrome (n = 10), and children with normal vision (n = 72). Methods: Interocular acuity differences and

  10. Monocular and binocular development in children with albinism, infantile nystagmus syndrome, and normal vision

    Huurneman, B.; Boonstra, F.N.

    2013-01-01

    Abstract Background/aims: To compare interocular acuity differences, crowding ratios, and binocular summation ratios in 4- to 8-year-old children with albinism (n = 16), children with infantile nystagmus syndrome (n = 10), and children with normal vision (n = 72). Methods: Interocular acuity

  11. The combined influence of binocular disparity and shading on pictorial shape

    Doorschot, P. C A; Kappers, A. M L; Koenderink, Jan J.

    The combined influence of binocular disparity and shading on pictorial shape was studied. Stimuli were several pairs of stereo photographs of real objects. The stereo base was 0, 7, or 14 cm, and the location of the light source was varied over three positions (one from about the viewpoint of the

  12. Visual and binocular status in elementary school children with a reading problem.

    Christian, Lisa W; Nandakumar, Krithika; Hrynchak, Patricia K; Irving, Elizabeth L

    2017-11-21

    This descriptive study provides a summary of the binocular anomalies seen in elementary school children identified with reading problems. A retrospective chart review of all children identified with reading problems and seen by the University of Waterloo, Optometry Clinic, from September 2012 to June 2013. Files of 121 children (mean age 8.6 years, range 6-14 years) were reviewed. No significant refractive error was found in 81% of children. Five and 8 children were identified as strabismic at distance and near respectively. Phoria test revealed 90% and 65% of patients had normal distance and near phoria. Near point of convergencia (NPC) was <5cm in 68% of children, and 77% had stereoacuity of ≤40seconds of arc. More than 50% of the children had normal fusional vergence ranges except for near positive fusional vergencce (base out) break (46%). Tests for accommodation showed 91% of children were normal for binocular facility, and approximately 70% of children had an expected accuracy of accommodation. Findings indicate that some children with an identified reading problem also present with abnormal binocular test results compared to published normal values. Further investigation should be performed to investigate the relationship between binocular vision function and reading performance. Crown Copyright © 2017. Published by Elsevier España, S.L.U. All rights reserved.

  13. Binocular contrast-gain control for natural scenes: Image structure and phase alignment.

    Huang, Pi-Chun; Dai, Yu-Ming

    2018-05-01

    In the context of natural scenes, we applied the pattern-masking paradigm to investigate how image structure and phase alignment affect contrast-gain control in binocular vision. We measured the discrimination thresholds of bandpass-filtered natural-scene images (targets) under various types of pedestals. Our first experiment had four pedestal types: bandpass-filtered pedestals, unfiltered pedestals, notch-filtered pedestals (which enabled removal of the spatial frequency), and misaligned pedestals (which involved rotation of unfiltered pedestals). Our second experiment featured six types of pedestals: bandpass-filtered, unfiltered, and notch-filtered pedestals, and the corresponding phase-scrambled pedestals. The thresholds were compared for monocular, binocular, and dichoptic viewing configurations. The bandpass-filtered pedestal and unfiltered pedestals showed classic dipper shapes; the dipper shapes of the notch-filtered, misaligned, and phase-scrambled pedestals were weak. We adopted a two-stage binocular contrast-gain control model to describe our results. We deduced that the phase-alignment information influenced the contrast-gain control mechanism before the binocular summation stage and that the phase-alignment information and structural misalignment information caused relatively strong divisive inhibition in the monocular and interocular suppression stages. When the pedestals were phase-scrambled, the elimination of the interocular suppression processing was the most convincing explanation of the results. Thus, our results indicated that both phase-alignment information and similar image structures cause strong interocular suppression. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Human cortical neural correlates of visual fatigue during binocular depth perception: An fNIRS study.

    Tingting Cai

    Full Text Available Functional near-infrared spectroscopy (fNIRS was adopted to investigate the cortical neural correlates of visual fatigue during binocular depth perception for different disparities (from 0.1° to 1.5°. By using a slow event-related paradigm, the oxyhaemoglobin (HbO responses to fused binocular stimuli presented by the random-dot stereogram (RDS were recorded over the whole visual dorsal area. To extract from an HbO curve the characteristics that are correlated with subjective experiences of stereopsis and visual fatigue, we proposed a novel method to fit the time-course HbO curve with various response functions which could reflect various processes of binocular depth perception. Our results indicate that the parietal-occipital cortices are spatially correlated with binocular depth perception and that the process of depth perception includes two steps, associated with generating and sustaining stereovision. Visual fatigue is caused mainly by generating stereovision, while the amplitude of the haemodynamic response corresponding to sustaining stereovision is correlated with stereopsis. Combining statistical parameter analysis and the fitted time-course analysis, fNIRS could be a promising method to study visual fatigue and possibly other multi-process neural bases.

  15. Touch interacts with vision during binocular rivalry with a tight orientation tuning.

    Claudia Lunghi

    Full Text Available Multisensory integration is a common feature of the mammalian brain that allows it to deal more efficiently with the ambiguity of sensory input by combining complementary signals from several sensory sources. Growing evidence suggests that multisensory interactions can occur as early as primary sensory cortices. Here we present incompatible visual signals (orthogonal gratings to each eye to create visual competition between monocular inputs in primary visual cortex where binocular combination would normally take place. The incompatibility prevents binocular fusion and triggers an ambiguous perceptual response in which the two images are perceived one at a time in an irregular alternation. One key function of multisensory integration is to minimize perceptual ambiguity by exploiting cross-sensory congruence. We show that a haptic signal matching one of the visual alternatives helps disambiguate visual perception during binocular rivalry by both prolonging the dominance period of the congruent visual stimulus and by shortening its suppression period. Importantly, this interaction is strictly tuned for orientation, with a mismatch as small as 7.5° between visual and haptic orientations sufficient to annul the interaction. These results indicate important conclusions: first, that vision and touch interact at early levels of visual processing where interocular conflicts are first detected and orientation tunings are narrow, and second, that haptic input can influence visual signals outside of visual awareness, bringing a stimulus made invisible by binocular rivalry suppression back to awareness sooner than would occur without congruent haptic input.

  16. The effect of image position on the Independent Components of natural binocular images.

    Hunter, David W; Hibbard, Paul B

    2018-01-11

    Human visual performance degrades substantially as the angular distance from the fovea increases. This decrease in performance is found for both binocular and monocular vision. Although analysis of the statistics of natural images has provided significant insights into human visual processing, little research has focused on the statistical content of binocular images at eccentric angles. We applied Independent Component Analysis to rectangular image patches cut from locations within binocular images corresponding to different degrees of eccentricity. The distribution of components learned from the varying locations was examined to determine how these distributions varied across eccentricity. We found a general trend towards a broader spread of horizontal and vertical position disparity tunings in eccentric regions compared to the fovea, with the horizontal spread more pronounced than the vertical spread. Eccentric locations above the centroid show a strong bias towards far-tuned components, eccentric locations below the centroid show a strong bias towards near-tuned components. These distributions exhibit substantial similarities with physiological measurements in V1, however in common with previous research we also observe important differences, in particular distributions of binocular phase disparity which do not match physiology.

  17. CONTRIBUTION OF INDIRECT TAXES

    CHIRCULESCU MARIA FELICIA

    2015-08-01

    Full Text Available The work is based on the fact that at any time and in any society, taxation is regarded as undesirable for all taxpayers. The existence and it's manifestation is justified, because the operation of any company involves costs that must be covered by sufficient resources. Since ancient times, each state has adopted its own tax system, more or less perfected, as the state has experienced a greater or lesser economic and military power At the base of this work stays the fact that tax systems are a key factor influencing the overall efficiency of the economy. They determine the size tendency to save, invest and work, influencing the increase in production and employment, which is essential sights integral economic strategy, making tax reform an important component of economic reform. This paper aims to analyze the indirect taxes and their contribution to the public revenues in Romania, the purpose paper contains an analysis based on statistical series as indirect taxation is where tax harmonization was possible. Through analyzes, the paper aims to provide answers to the problem of the contradiction between the growing need for budgetary revenues, which entails a continuous amplification and diversification of taxation, on the one hand, and the need to stimulate economic development, on the other hand. The harmonization of indirect taxation had been achieved since this touches the free movement of goods and the freedom to supply services, not being able to say the same thing about direct taxation, which is why the European Community Treaty does not specify expressly the alignment of direct taxation, considering that direct taxation is a matter of Internal Policies that, for a country free option.

  18. On the functional order of binocular rivalry and blind spot filling-in.

    Qian, Cheng S; Brascamp, Jan W; Liu, Taosheng

    2017-07-01

    Binocular rivalry is an important phenomenon for understanding the mechanisms of visual awareness. Here we assessed the functional locus of binocular rivalry relative to blind spot filling-in, which is thought to transpire in V1, thus providing a reference point for assessing the locus of rivalry. We conducted two experiments to explore the functional order of binocular rivalry and blind spot filling-in. Experiment 1 examined if the information filled-in at the blind spot can engage in rivalry with a physical stimulus at the corresponding location in the fellow eye. Participants' perceptual reports showed no difference between this condition and a condition where filling-in was precluded by presenting the same stimuli away from the blind spot, suggesting that the rivalry process is not influenced by any filling-in that might occur. In Experiment 2, we presented the fellow eye's stimulus directly in rivalry with the 'inducer' stimulus that surrounds the blind spot, and compared it with two control conditions away from the blind spot: one involving a ring physically identical to the inducer, and one involving a disc that resembled the filled-in percept. Perceptual reports in the blind spot condition resembled those in the 'ring' condition, more than those in the latter, 'disc' condition, indicating that a perceptually suppressed inducer does not engender filling-in. Thus, our behavioral data suggest binocular rivalry functionally precedes blind spot filling-in. We conjecture that the neural substrate of binocular rivalry suppression includes processing stages at or before V1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Contrast masking in strabismic amblyopia: attenuation, noise, interocular suppression and binocular summation.

    Baker, Daniel H; Meese, Tim S; Hess, Robert F

    2008-07-01

    To investigate amblyopic contrast vision at threshold and above we performed pedestal-masking (contrast discrimination) experiments with a group of eight strabismic amblyopes using horizontal sinusoidal gratings (mainly 3c/deg) in monocular, binocular and dichoptic configurations balanced across eye (i.e. five conditions). With some exceptions in some observers, the four main results were as follows. (1) For the monocular and dichoptic conditions, sensitivity was less in the amblyopic eye than in the good eye at all mask contrasts. (2) Binocular and monocular dipper functions superimposed in the good eye. (3) Monocular masking functions had a normal dipper shape in the good eye, but facilitation was diminished in the amblyopic eye. (4) A less consistent result was normal facilitation in dichoptic masking when testing the good eye, but a loss of this when testing the amblyopic eye. This pattern of amblyopic results was replicated in a normal observer by placing a neutral density filter in front of one eye. The two-stage model of binocular contrast gain control [Meese, T.S., Georgeson, M.A. & Baker, D.H. (2006). Binocular contrast vision at and above threshold. Journal of Vision 6, 1224-1243.] was 'lesioned' in several ways to assess the form of the amblyopic deficit. The most successful model involves attenuation of signal and an increase in noise in the amblyopic eye, and intact stages of interocular suppression and binocular summation. This implies a behavioural influence from monocular noise in the amblyopic visual system as well as in normal observers with an ND filter over one eye.

  20. Binocular Therapy for Childhood Amblyopia Improves Vision Without Breaking Interocular Suppression.

    Bossi, Manuela; Tailor, Vijay K; Anderson, Elaine J; Bex, Peter J; Greenwood, John A; Dahlmann-Noor, Annegret; Dakin, Steven C

    2017-06-01

    Amblyopia is a common developmental visual impairment characterized by a substantial difference in acuity between the two eyes. Current monocular treatments, which promote use of the affected eye by occluding or blurring the fellow eye, improve acuity, but are hindered by poor compliance. Recently developed binocular treatments can produce rapid gains in visual function, thought to be as a result of reduced interocular suppression. We set out to develop an effective home-based binocular treatment system for amblyopia that would engage high levels of compliance but that would also allow us to assess the role of suppression in children's response to binocular treatment. Balanced binocular viewing therapy (BBV) involves daily viewing of dichoptic movies (with "visibility" matched across the two eyes) and gameplay (to monitor compliance and suppression). Twenty-two children (3-11 years) with anisometropic (n = 7; group 1) and strabismic or combined mechanism amblyopia (group 2; n = 6 and 9, respectively) completed the study. Groups 1 and 2 were treated for a maximum of 8 or 24 weeks, respectively. The treatment elicited high levels of compliance (on average, 89.4% ± 24.2% of daily dose in 68.23% ± 12.2% of days on treatment) and led to a mean improvement in acuity of 0.27 logMAR (SD 0.22) for the amblyopic eye. Importantly, acuity gains were not correlated with a reduction in suppression. BBV is a binocular treatment for amblyopia that can be self-administered at home (with remote monitoring), producing rapid and substantial benefits that cannot be solely mediated by a reduction in interocular suppression.

  1. A new binocular approach to the treatment of amblyopia in adults well beyond the critical period of visual development.

    Hess, R F; Mansouri, B; Thompson, B

    2010-01-01

    The present treatments for amblyopia are predominantly monocular aiming to improve the vision in the amblyopic eye through either patching of the fellow fixing eye or visual training of the amblyopic eye. This approach is problematic, not least of which because it rarely results in establishment of binocular function. Recently it has shown that amblyopes possess binocular cortical mechanisms for both threshold and suprathreshold stimuli. We outline a novel procedure for measuring the extent to which the fixing eye suppresses the fellow amblyopic eye, rendering what is a structurally binocular system, functionally monocular. Here we show that prolonged periods of viewing (under the artificial conditions of stimuli of different contrast in each eye) during which information from the two eyes is combined leads to a strengthening of binocular vision in strabismic amblyopes and eventual combination of binocular information under natural viewing conditions (stimuli of the same contrast in each eye). Concomitant improvement in monocular acuity of the amblyopic eye occurs with this reduction in suppression and strengthening of binocular fusion. Furthermore, in a majority of patients tested, stereoscopic function is established. This provides the basis for a new treatment of amblyopia, one that is purely binocular and aimed at reducing suppression as a first step.

  2. Optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy in retinal nerve fiber layer measurements of glaucoma patients.

    Fanihagh, Farsad; Kremmer, Stephan; Anastassiou, Gerasimos; Schallenberg, Maurice

    2015-01-01

    To determine the correlations and strength of association between different imaging systems in analyzing the retinal nerve fiber layer (RNFL) of glaucoma patients: optical coherence tomography (OCT), scanning laser polarimetry (SLP) and confocal scanning laser ophthalmoscopy (CSLO). 114 eyes of patients with moderate open angle glaucoma underwent spectral domain OCT (Topcon SD-OCT 2000 and Zeiss Cirrus HD-OCT), SLP (GDx VCC and GDx Pro) and CSLO (Heidelberg Retina Tomograph, HRT 3). Correlation coefficients were calculated between the structural parameters yielded by these examinations. The quantitative relationship between the measured RNFL thickness globally and for the four regions (superior, inferior, nasal, temporal) were evaluated with different regression models for all used imaging systems. The strongest correlation of RNFL measurements was found between devices using the same technology like GDx VCC and GDx Pro as well as Topcon OCT and Cirrus OCT. In glaucoma patients, the strongest associations (R²) were found between RNFL measurements of the two optical coherence tomography devices Topcon OCT and Cirrus OCT (R² = 0.513) and between GDx VCC and GDx Pro (R² = 0.451). The results of the OCTs and GDX Pro also had a strong quantitative relationship (Topcon OCT R² = 0.339 and Cirrus OCT R² = 0.347). GDx VCC and the OCTs showed a mild to moderate association (Topcon OCT R² = 0.207 and Cirrus OCT R² = 0.258). The confocal scanning laser ophthalmoscopy (HRT 3) had the lowest association to all other devices (Topcon OCT R² = 0.254, Cirrus OCT R² = 0.158, GDx Pro R² = 0.086 and GDx VCC R² = 0.1). The measurements of the RNFL in glaucoma patients reveal a high correlation of OCT and GDx devices because OCTs can measure all major retinal layers and SLP can detect nerve fibers allowing a comparison between the results of this devices. However, CSLO by means of HRT topography can only measure height values of the retinal surface but it cannot distinguish

  3. Binocular treatment of amblyopia using videogames (BRAVO): study protocol for a randomised controlled trial.

    Guo, Cindy X; Babu, Raiju J; Black, Joanna M; Bobier, William R; Lam, Carly S Y; Dai, Shuan; Gao, Tina Y; Hess, Robert F; Jenkins, Michelle; Jiang, Yannan; Kowal, Lionel; Parag, Varsha; South, Jayshree; Staffieri, Sandra Elfride; Walker, Natalie; Wadham, Angela; Thompson, Benjamin

    2016-10-18

    Amblyopia is a common neurodevelopmental disorder of vision that is characterised by visual impairment in one eye and compromised binocular visual function. Existing evidence-based treatments for children include patching the nonamblyopic eye to encourage use of the amblyopic eye. Currently there are no widely accepted treatments available for adults with amblyopia. The aim of this trial is to assess the efficacy of a new binocular, videogame-based treatment for amblyopia in older children and adults. We hypothesise that binocular treatment will significantly improve amblyopic eye visual acuity relative to placebo treatment. The BRAVO study is a double-blind, randomised, placebo-controlled multicentre trial to assess the effectiveness of a novel videogame-based binocular treatment for amblyopia. One hundred and eight participants aged 7 years or older with anisometropic and/or strabismic amblyopia (defined as ≥0.2 LogMAR interocular visual acuity difference, ≥0.3 LogMAR amblyopic eye visual acuity and no ocular disease) will be recruited via ophthalmologists, optometrists, clinical record searches and public advertisements at five sites in New Zealand, Canada, Hong Kong and Australia. Eligible participants will be randomised by computer in a 1:1 ratio, with stratification by age group: 7-12, 13-17 and 18 years and older. Participants will be randomised to receive 6 weeks of active or placebo home-based binocular treatment. Treatment will be in the form of a modified interactive falling-blocks game, implemented on a 5th generation iPod touch device viewed through red/green anaglyphic glasses. Participants and those assessing outcomes will be blinded to group assignment. The primary outcome is the change in best-corrected distance visual acuity in the amblyopic eye from baseline to 6 weeks post randomisation. Secondary outcomes include distance and near visual acuity, stereopsis, interocular suppression, angle of strabismus (where applicable) measured at

  4. Binocular iPad Game vs Patching for Treatment of Amblyopia in Children: A Randomized Clinical Trial.

    Kelly, Krista R; Jost, Reed M; Dao, Lori; Beauchamp, Cynthia L; Leffler, Joel N; Birch, Eileen E

    2016-12-01

    Fellow eye patching has long been the standard treatment for amblyopia, but it does not always restore 20/20 vision or teach the eyes to work together. Amblyopia can be treated with binocular games that rebalance contrast between the eyes so that a child may overcome suppression. However, it is unclear whether binocular treatment is comparable to patching in treating amblyopia. To assess the effectiveness of a binocular iPad (Apple Inc) adventure game as amblyopia treatment and compare this binocular treatment with patching, the current standard of care. This investigation was a randomized clinical trial with a crossover design at a nonprofit eye research institute. Between February 20, 2015, and January 4, 2016, a total of 28 patients were enrolled in the study, with 14 randomized to binocular game treatment and 14 to patching treatment. Binocular game and patching as amblyopia treatments. The primary outcome was change in amblyopic eye best-corrected visual acuity (BCVA) at the 2-week visit. Secondary outcomes were change in stereoacuity and suppression at the 2-week visit and change in BCVA at the 4-week visit. Among 28 children, the mean (SD) age at baseline was 6.7 (1.4) years (age range, 4.6-9.5 years), and 7 (25%) were female. At baseline, the mean (SD) amblyopic eye BCVA was 0.48 (0.14) logMAR (approximately 20/63; range, 0.3-0.8 logMAR [20/40 to 20/125]), with 14 children randomized to the binocular game and 14 to patching for 2 weeks. At the 2-week visit, improvement in amblyopic eye BCVA was greater with the binocular game compared with patching, with a mean (SD) improvement of 0.15 (0.08) logMAR (mean [SD], 1.5 [0.8] lines) vs 0.07 (0.08) logMAR (mean [SD], 0.7 [0.8] line; P = .02) after 2 weeks of treatment. These improvements from baseline were significant for the binocular game (mean [SD] improvement, 1.5 [0.8] lines; P suppression improved from baseline at the 2-week visit for the binocular game (mean [SD], 4.82 [2.82] vs 3.24 [2.87]; P

  5. Large Binocular Telescope Observations of Europa Occulting Io's Volcanoes at 4.8 μm

    Skrutskie, Michael F.; Conrad, Albert; Resnick, Aaron; Leisenring, Jarron; Hinz, Phil; de Pater, Imke; de Kleer, Katherine; Spencer, John; Skemer, Andrew; Woodward, Charles E.; Davies, Ashley Gerard; Defrére, Denis

    2015-11-01

    On 8 March 2015 Europa passed nearly centrally in front of Io. The Large Binocular Telescope observed this event in dual-aperture AO-corrected Fizeau interferometric imaging mode using the mid-infrared imager LMIRcam operating behind the Large Binocular Telescope Interferometer (LBTI) at a broadband wavelength of 4.8 μm (M-band). Occultation light curves generated from frames recorded every 123 milliseconds show that both Loki and Pele/Pillan were well resolved. Europa's center shifted by 2 kilometers relative to Io from frame-to-frame. The derived light curve for Loki is consistent with the double-lobed structure reported by Conrad et al. (2015) using direct interferometric imaging with LBTI.

  6. Camera calibration method of binocular stereo vision based on OpenCV

    Zhong, Wanzhen; Dong, Xiaona

    2015-10-01

    Camera calibration, an important part of the binocular stereo vision research, is the essential foundation of 3D reconstruction of the spatial object. In this paper, the camera calibration method based on OpenCV (open source computer vision library) is submitted to make the process better as a result of obtaining higher precision and efficiency. First, the camera model in OpenCV and an algorithm of camera calibration are presented, especially considering the influence of camera lens radial distortion and decentering distortion. Then, camera calibration procedure is designed to compute those parameters of camera and calculate calibration errors. High-accurate profile extraction algorithm and a checkboard with 48 corners have also been used in this part. Finally, results of calibration program are presented, demonstrating the high efficiency and accuracy of the proposed approach. The results can reach the requirement of robot binocular stereo vision.

  7. The influence of chromatic context on binocular color rivalry: Perception and neural representation

    Hong, Sang Wook; Shevell, Steven K.

    2008-01-01

    The predominance of rivalrous targets is affected by surrounding context when stimuli rival in orientation, motion or color. This study investigated the influence of chromatic context on binocular color rivalry. The predominance of rivalrous chromatic targets was measured in various surrounding contexts. The first experiment showed that a chromatic surround's influence was stronger when the surround was uniform or a grating with luminance contrast (chromatic/black grating) compared to an equiluminant grating (chromatic/white). The second experiment revealed virtually no effect of the orientation of the surrounding chromatic context, using chromatically rivalrous vertical gratings. These results are consistent with a chromatic representation of the context by a non-oriented, chromatically selective and spatially antagonistic receptive field. Neither a double-opponent receptive field nor a receptive field without spatial antagonism accounts for the influence of context on binocular color rivalry. PMID:18331750

  8. Research on detection method of UAV obstruction based on binocular vision

    Zhu, Xiongwei; Lei, Xusheng; Sui, Zhehao

    2018-04-01

    For the autonomous obstacle positioning and ranging in the process of UAV (unmanned aerial vehicle) flight, a system based on binocular vision is constructed. A three-stage image preprocessing method is proposed to solve the problem of the noise and brightness difference in the actual captured image. The distance of the nearest obstacle is calculated by using the disparity map that generated by binocular vision. Then the contour of the obstacle is extracted by post-processing of the disparity map, and a color-based adaptive parameter adjustment algorithm is designed to extract contours of obstacle automatically. Finally, the safety distance measurement and obstacle positioning during the UAV flight process are achieved. Based on a series of tests, the error of distance measurement can keep within 2.24% of the measuring range from 5 m to 20 m.

  9. On the contribution of binocular disparity to the long-term memory for natural scenes.

    Matteo Valsecchi

    Full Text Available Binocular disparity is a fundamental dimension defining the input we receive from the visual world, along with luminance and chromaticity. In a memory task involving images of natural scenes we investigate whether binocular disparity enhances long-term visual memory. We found that forest images studied in the presence of disparity for relatively long times (7s were remembered better as compared to 2D presentation. This enhancement was not evident for other categories of pictures, such as images containing cars and houses, which are mostly identified by the presence of distinctive artifacts rather than by their spatial layout. Evidence from a further experiment indicates that observers do not retain a trace of stereo presentation in long-term memory.

  10. The Role of Binocular Disparity in Rapid Scene and Pattern Recognition

    Matteo Valsecchi

    2013-04-01

    Full Text Available We investigated the contribution of binocular disparity to the rapid recognition of scenes and simpler spatial patterns using a paradigm combining backward masked stimulus presentation and short-term match-to-sample recognition. First, we showed that binocular disparity did not contribute significantly to the recognition of briefly presented natural and artificial scenes, even when the availability of monocular cues was reduced. Subsequently, using dense random dot stereograms as stimuli, we showed that observers were in principle able to extract spatial patterns defined only by disparity under brief, masked presentations. Comparing our results with the predictions from a cue-summation model, we showed that combining disparity with luminance did not per se disrupt the processing of disparity. Our results suggest that the rapid recognition of scenes is mediated mostly by a monocular comparison of the images, although we can rely on stereo in fast pattern recognition.

  11. An iPod treatment of amblyopia: an updated binocular approach.

    Hess, Robert F; Thompson, B; Black, J M; Machara, G; Zhang, P; Bobier, W R; Cooperstock, J

    2012-02-15

    We describe the successful translation of computerized and space-consuming laboratory equipment for the treatment of suppression to a small handheld iPod device (Apple iPod; Apple Inc., Cupertino, California). A portable and easily obtainable Apple iPod display, using current video technology offers an ideal solution for the clinical treatment of suppression. The following is a description of the iPod device and illustrates how a video game has been adapted to provide the appropriate stimulation to implement our recent antisuppression treatment protocol. One to 2 hours per day of video game playing under controlled conditions for 1 to 3 weeks can improve acuity and restore binocular function, including stereopsis in adults, well beyond the age at which traditional patching is used. This handheld platform provides a convenient and effective platform for implementing the newly proposed binocular treatment of amblyopia in the clinic, home, or elsewhere. American Optometric Association.

  12. A novel apparatus for testing binocular function using the 'CyberDome' three-dimensional hemispherical visual display system.

    Handa, T; Ishikawa, H; Shimizu, K; Kawamura, R; Nakayama, H; Sawada, K

    2009-11-01

    Virtual reality has recently been highlighted as a promising medium for visual presentation and entertainment. A novel apparatus for testing binocular visual function using a hemispherical visual display system, 'CyberDome', has been developed and tested. Subjects comprised 40 volunteers (mean age, 21.63 years) with corrected visual acuity of -0.08 (LogMAR) or better, and stereoacuity better than 100 s of arc on the Titmus stereo test. Subjects were able to experience visual perception like being surrounded by visual images, a feature of the 'CyberDome' hemispherical visual display system. Visual images to the right and left eyes were projected and superimposed on the dome screen, allowing test images to be seen independently by each eye using polarizing glasses. The hemispherical visual display was 1.4 m in diameter. Three test parameters were evaluated: simultaneous perception (subjective angle of strabismus), motor fusion amplitude (convergence and divergence), and stereopsis (binocular disparity at 1260, 840, and 420 s of arc). Testing was performed in volunteer subjects with normal binocular vision, and results were compared with those using a major amblyoscope. Subjective angle of strabismus and motor fusion amplitude showed a significant correlation between our test and the major amblyoscope. All subjects could perceive the stereoscopic target with a binocular disparity of 480 s of arc. Our novel apparatus using the CyberDome, a hemispherical visual display system, was able to quantitatively evaluate binocular function. This apparatus offers clinical promise in the evaluation of binocular function.

  13. A special role for binocular visual input during development and as a component of occlusion therapy for treatment of amblyopia.

    Mitchell, Donald E

    2008-01-01

    To review work on animal models of deprivation amblyopia that points to a special role for binocular visual input in the development of spatial vision and as a component of occlusion (patching) therapy for amblyopia. The studies reviewed employ behavioural methods to measure the effects of various early experiential manipulations on the development of the visual acuity of the two eyes. Short periods of concordant binocular input, if continuous, can offset much longer daily periods of monocular deprivation to allow the development of normal visual acuity in both eyes. It appears that the visual system does not weigh all visual input equally in terms of its ability to impact on the development of vision but instead places greater weight on concordant binocular exposure. Experimental models of patching therapy for amblyopia imposed on animals in which amblyopia had been induced by a prior period of early monocular deprivation, indicate that the benefits of patching therapy may be only temporary and decline rapidly after patching is discontinued. However, when combined with critical amounts of binocular visual input each day, the benefits of patching can be both heightened and made permanent. Taken together with demonstrations of retained binocular connections in the visual cortex of monocularly deprived animals, a strong argument is made for inclusion of specific training of stereoscopic vision for part of the daily periods of binocular exposure that should be incorporated as part of any patching protocol for amblyopia.

  14. The wavelet transform and the suppression theory of binocular vision for stereo image compression

    Reynolds, W.D. Jr [Argonne National Lab., IL (United States); Kenyon, R.V. [Illinois Univ., Chicago, IL (United States)

    1996-08-01

    In this paper a method for compression of stereo images. The proposed scheme is a frequency domain approach based on the suppression theory of binocular vision. By using the information in the frequency domain, complex disparity estimation techniques can be avoided. The wavelet transform is used to obtain a multiresolution analysis of the stereo pair by which the subbands convey the necessary frequency domain information.

  15. Vision in avian emberizid foragers: maximizing both binocular vision and fronto-lateral visual acuity.

    Moore, Bret A; Pita, Diana; Tyrrell, Luke P; Fernández-Juricic, Esteban

    2015-05-01

    Avian species vary in their visual system configuration, but previous studies have often compared single visual traits between two to three distantly related species. However, birds use different visual dimensions that cannot be maximized simultaneously to meet different perceptual demands, potentially leading to trade-offs between visual traits. We studied the degree of inter-specific variation in multiple visual traits related to foraging and anti-predator behaviors in nine species of closely related emberizid sparrows, controlling for phylogenetic effects. Emberizid sparrows maximize binocular vision, even seeing their bill tips in some eye positions, which may enhance the detection of prey and facilitate food handling. Sparrows have a single retinal center of acute vision (i.e. fovea) projecting fronto-laterally (but not into the binocular field). The foveal projection close to the edge of the binocular field may shorten the time to gather and process both monocular and binocular visual information from the foraging substrate. Contrary to previous work, we found that species with larger visual fields had higher visual acuity, which may compensate for larger blind spots (i.e. pectens) above the center of acute vision, enhancing predator detection. Finally, species with a steeper change in ganglion cell density across the retina had higher eye movement amplitude, probably due to a more pronounced reduction in visual resolution away from the fovea, which would need to be moved around more frequently. The visual configuration of emberizid passive prey foragers is substantially different from that of previously studied avian groups (e.g. sit-and-wait and tactile foragers). © 2015. Published by The Company of Biologists Ltd.

  16. Binocular Vision-Based Position and Pose of Hand Detection and Tracking in Space

    Jun, Chen; Wenjun, Hou; Qing, Sheng

    After the study of image segmentation, CamShift target tracking algorithm and stereo vision model of space, an improved algorithm based of Frames Difference and a new space point positioning model were proposed, a binocular visual motion tracking system was constructed to verify the improved algorithm and the new model. The problem of the spatial location and pose of the hand detection and tracking have been solved.

  17. More superimposition for contrast-modulated than luminance-modulated stimuli during binocular rivalry.

    Skerswetat, Jan; Formankiewicz, Monika A; Waugh, Sarah J

    2018-01-01

    Luminance-modulated noise (LM) and contrast-modulated noise (CM) gratings were presented with interocularly correlated, uncorrelated and anti-correlated binary noise to investigate their contributions to mixed percepts, specifically piecemeal and superimposition, during binocular rivalry. Stimuli were sine-wave gratings of 2 c/deg presented within 2 deg circular apertures. The LM stimulus contrast was 0.1 and the CM stimulus modulation depth was 1.0, equating to approximately 5 and 7 times detection threshold, respectively. Twelve 45 s trials, per noise configuration, were carried out. Fifteen participants with normal vision indicated via button presses whether an exclusive, piecemeal or superimposed percept was seen. For all noise conditions LM stimuli generated more exclusive visibility, and lower proportions of superimposition. CM stimuli led to greater proportions and longer periods of superimposition. For both stimulus types, correlated interocular noise generated more superimposition than did anti- or uncorrelated interocular noise. No significant effect of stimulus type (LM vs CM) or noise configuration (correlated, uncorrelated, anti-correlated) on piecemeal perception was found. Exclusive visibility was greater in proportion, and perceptual changes more numerous, during binocular rivalry for CM stimuli when interocular noise was not correlated. This suggests that mutual inhibition, initiated by non-correlated noise CM gratings, occurs between neurons processing luminance noise (first-order component), as well as those processing gratings (second-order component). Therefore, first- and second-order components can contribute to overall binocular rivalry responses. We suggest the addition of a new well to the current energy landscape model for binocular rivalry that takes superimposition into account. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Quantitative measurement of binocular color fusion limit for non-spectral colors.

    Jung, Yong Ju; Sohn, Hosik; Lee, Seong-il; Ro, Yong Man; Park, Hyun Wook

    2011-04-11

    Human perception becomes difficult in the event of binocular color fusion when the color difference presented for the left and right eyes exceeds a certain threshold value, known as the binocular color fusion limit. This paper discusses the binocular color fusion limit for non-spectral colors within the color gamut of a conventional LCD 3DTV. We performed experiments to measure the color fusion limit for eight chromaticity points sampled from the CIE 1976 chromaticity diagram. A total of 2480 trials were recorded for a single observer. By analyzing the results, the color fusion limit was quantified by ellipses in the chromaticity diagram. The semi-minor axis of the ellipses ranges from 0.0415 to 0.0923 in terms of the Euclidean distance in the u'v´ chromaticity diagram and the semi-major axis ranges from 0.0640 to 0.1560. These eight ellipses are drawn on the chromaticity diagram. © 2011 Optical Society of America

  19. A quantitative measurement of binocular color fusion limit for different disparities

    Chen, Zaiqing; Shi, Junsheng; Tai, Yonghan; Huang, Xiaoqiao; Yun, Lijun; Zhang, Chao

    2018-01-01

    Color asymmetry is a common phenomenon in stereoscopic display system, which can cause visual fatigue or visual discomfort. When the color difference between the left and right eyes exceeds a threshold value, named binocular color fusion limit, color rivalry is said to occur. The most important information brought by stereoscopic displays is the depth perception produced by the disparity. As the stereo pair stimuli are presented separately to both eyes with disparities and those two monocular stimuli differ in color but share an iso-luminance polarity, it is possible for stereopsis and color rivalry to coexist. In this paper, we conducted an experiment to measure the color fusion limit for different disparity levels. In particular, it examines how the magnitude and sign of disparity affect the binocular color fusion limit that yields a fused, stable stereoscopic percept. The binocular color fusion limit was measured at five levels of disparities: 0, +/-60, +/-120 arc minutes for a sample color point which was selected from the 1976 CIE u'v' chromaticity diagram. The experimental results showed that fusion limit for the sample point varied with the level and sign of disparity. It was an interesting result that the fusion limit increased as the disparity decreases at crossed disparity direction (sign -), but there is almost no big change at uncrossed disparity direction (sign +). We found that color fusion was more difficult to achieve at the crossed disparity direction than at the uncrossed disparity direction.

  20. Ecomorphology of orbit orientation and the adaptive significance of binocular vision in primates and other mammals.

    Heesy, Christopher P

    2008-01-01

    Primates are characterized by forward-facing, or convergent, orbits and associated binocular field overlap. Hypotheses explaining the adaptive significance of these traits often relate to ecological factors, such as arboreality, nocturnal visual predation, or saltatory locomotion in a complex nocturnal, arboreal environment. This study re-examines the ecological factors that are associated with high orbit convergence in mammals. Orbit orientation data were collected for 321 extant taxa from sixteen orders of metatherian (marsupial) and eutherian mammals. These taxa were coded for activity pattern, degree of faunivory, and substrate preference. Results demonstrate that nocturnal and cathemeral mammals have significantly more convergent orbits than diurnal taxa, both within and across orders. Faunivorous eutherians (both nocturnal and diurnal) have higher mean orbit convergence than opportunistically foraging or non-faunivorous taxa. However, substrate preference is not associated with higher orbit convergence and, by extension, greater binocular visual field overlap. These results are consistent with the hypothesis that mammalian predators evolved higher orbit convergence, binocular vision, and stereopsis to counter camouflage in prey inhabiting a nocturnal environment. Strepsirhine primates have a range of orbit convergence values similar to nocturnal or cathemeral predatory non-primate mammals. These data are entirely consistent with the nocturnal visual predation hypothesis of primate origins. (c) 2007 S. Karger AG, Basel.

  1. Loss of binocular vision as direct cause for misrouting of temporal retinal fibers in albinism.

    Banihani, Saleh M

    2015-10-01

    In humans, the nasal retina projects to the contralateral hemisphere, whereas the temporal retina projects ipsilaterally. The nasotemporal line that divides the retina into crossed and uncrossed parts coincides with the vertical meridian through the fovea. This normal projection of the retina is severely altered in albinism, in which the nasotemporal line shifted into the temporal retina with temporal retinal fibers cross the midline at the optic chiasm. This study proposes the loss of binocular vision as direct cause for misrouting of temporal retinal fibers and shifting of the nasotemporal line temporally in albinism. It is supported by many observations that clearly indicate that loss of binocular vision causes uncrossed retinal fibers to cross the midline. This hypothesis may alert scientists and clinicians to find ways to prevent or minimize the loss of binocular vision that may occur in some diseases such as albinism and early squint. Hopefully, this will minimize the misrouting of temporal fibers and improve vision in such diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Calculation method of CGH for Binocular Eyepiece-Type Electro Holography

    Yang, Chanyoung; Yoneyama, Takuo; Sakamoto, Yuji; Okuyama, Fumio

    2013-01-01

    We had researched about eyepiece-type electro holography to display 3-D images of larger objects at wider angle. We had enlarged visual field considering depth of object with Fourier optical system using two lenses. In this paper, we extend our system for binocular. In the binocular system, we use two different holograms for each eye. The 3-D image for left eye should be observed like the real object observed using left eye and the same for right eye. So, we propose a method of calculation of computer-generated hologram (CGH) transforming the coordinate system of the model data to make two holograms for binocular eyepiece-type electro holography. The coordinate system of original model data is called the world coordinate system. The left and the right coordinate system are transformed from the world coordinate system. We also propose the method for correcting the installation error that occurs when placing the electronic and optical devices. The installation error is calculated and the model data is corrected using the distance between measured position and setup position of the reconstructed image Optical reconstruction experiments were carried out to verify the proposed method.

  3. Corneal Transplantation in Disease Affecting Only One Eye: Does It Make a Difference to Habitual Binocular Viewing?

    Praveen K Bandela

    Full Text Available Clarity of the transplanted tissue and restoration of visual acuity are the two primary metrics for evaluating the success of corneal transplantation. Participation of the transplanted eye in habitual binocular viewing is seldom evaluated post-operatively. In unilateral corneal disease, the transplanted eye may remain functionally inactive during binocular viewing due to its suboptimal visual acuity and poor image quality, vis-à-vis the healthy fellow eye.This study prospectively quantified the contribution of the transplanted eye towards habitual binocular viewing in 25 cases with unilateral transplants [40 yrs (IQR: 32-42 yrs and 25 age-matched controls [30 yrs (25-37 yrs]. Binocular functions including visual field extent, high-contrast logMAR acuity, suppression threshold and stereoacuity were assessed using standard psychophysical paradigms. Optical quality of all eyes was determined from wavefront aberrometry measurements. Binocular visual field expanded by a median 21% (IQR: 18-29% compared to the monocular field of cases and controls (p = 0.63. Binocular logMAR acuity [0.0 (0.0-0.0] almost always followed the fellow eye's acuity [0.00 (0.00 --0.02] (r = 0.82, independent of the transplanted eye's acuity [0.34 (0.2-0.5] (r = 0.04. Suppression threshold and stereoacuity were poorer in cases [30.1% (13.5-44.3%; 620.8 arc sec (370.3-988.2 arc sec] than in controls [79% (63.5-100%; 16.3 arc sec (10.6-25.5 arc sec] (p<0.001. Higher-order wavefront aberrations of the transplanted eye [0.34 μ (0.21-0.51 μ] were higher than the fellow eye [0.07 μ (0.05-0.11 μ] (p<0.001 and their reduction with RGP contact lenses [0.09 μ (0.08-0.12 μ] significantly improved the suppression threshold [65% (50-72%] and stereoacuity [56.6 arc sec (47.7-181.6 arc sec] (p<0.001.In unilateral corneal disease, the transplanted eye does participate in gross binocular viewing but offers limited support to fine levels of binocularity. Improvement in the transplanted

  4. Image-guided intraocular injection using multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy in rodent ophthalmological models

    Terrones, Benjamin D.; Benavides, Oscar R.; Leeburg, Kelsey C.; Mehanathan, Sankarathi B.; Levine, Edward M.; Tao, Yuankai K.

    2018-02-01

    Intraocular injections are routinely performed for delivery of anti-VEGF and anti-inflammatory therapies in humans. While these injections are also performed in mice to develop novel models of ophthalmic diseases and screen novel therapeutics, the injection location and volume are not well-controlled and reproducible. We overcome limitations of conventional injections methods by developing a multimodality, long working distance, non-contact optical coherence tomography (OCT) and fluorescence confocal scanning laser ophthalmoscopy (cSLO) system for retinal imaging before and after injections. Our OCT+cSLO system combines a custom-built spectraldomain OCT engine (875+/-85 nm) with 125 kHz line-rate with a modified commercial cSLO with a maximum frame-rate of 30 fps (512 x 512 pix.). The system was designed for an overlapping OCT+cSLO field-of-view of 1.1 mm with a 7.76 mm working distance to the pupil. cSLO excitation light sources and filters were optimized for simultaneous GFP and tdTomato imaging. Lateral resolution was 3.02 µm for OCT and 2.74 μm for cSLO. Intravitreal injections of 5%, 10%, and 20% intralipid with Alex Fluor 488 were manually injected intraocularly in C57BL/6 mice. Post-injection imaging showed structural changes associated with retinal puncture, including the injection track, a retinal elevation, and detachment of the posterior hyaloid. OCT enables quantitative analysis of injection location and volumes whereas complementary cSLO improves specificity for identifying fluorescently labeled injected compounds and transgenic cells. The long working distance of our non-contact OCT+cSLO system is uniquely-suited for concurrent imaging with intraocular injections and may be applied for imaging of ophthalmic surgical dynamics and real-time image-guided injections.

  5. High-resolution imaging of the retinal nerve fiber layer in normal eyes using adaptive optics scanning laser ophthalmoscopy.

    Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Arakawa, Naoko; Oshima, Susumu; Shibata, Naohisa; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

    2012-01-01

    To conduct high-resolution imaging of the retinal nerve fiber layer (RNFL) in normal eyes using adaptive optics scanning laser ophthalmoscopy (AO-SLO). AO-SLO images were obtained in 20 normal eyes at multiple locations in the posterior polar area and a circular path with a 3-4-mm diameter around the optic disc. For each eye, images focused on the RNFL were recorded and a montage of AO-SLO images was created. AO-SLO images for all eyes showed many hyperreflective bundles in the RNFL. Hyperreflective bundles above or below the fovea were seen in an arch from the temporal periphery on either side of a horizontal dividing line to the optic disc. The dark lines among the hyperreflective bundles were narrower around the optic disc compared with those in the temporal raphe. The hyperreflective bundles corresponded with the direction of the striations on SLO red-free images. The resolution and contrast of the bundles were much higher in AO-SLO images than in red-free fundus photography or SLO red-free images. The mean hyperreflective bundle width around the optic disc had a double-humped shape; the bundles at the temporal and nasal sides of the optic disc were narrower than those above and below the optic disc (Poptical coherence tomography correlated with the hyperreflective bundle widths on AO-SLO (Pfiber bundles and Müller cell septa. The widths of the nerve fiber bundles appear to be proportional to the RNFL thickness at equivalent distances from the optic disc.

  6. High-resolution imaging of retinal nerve fiber bundles in glaucoma using adaptive optics scanning laser ophthalmoscopy.

    Takayama, Kohei; Ooto, Sotaro; Hangai, Masanori; Ueda-Arakawa, Naoko; Yoshida, Sachiko; Akagi, Tadamichi; Ikeda, Hanako Ohashi; Nonaka, Atsushi; Hanebuchi, Masaaki; Inoue, Takashi; Yoshimura, Nagahisa

    2013-05-01

    To detect pathologic changes in retinal nerve fiber bundles in glaucomatous eyes seen on images obtained by adaptive optics (AO) scanning laser ophthalmoscopy (AO SLO). Prospective cross-sectional study. Twenty-eight eyes of 28 patients with open-angle glaucoma and 21 normal eyes of 21 volunteer subjects underwent a full ophthalmologic examination, visual field testing using a Humphrey Field Analyzer, fundus photography, red-free SLO imaging, spectral-domain optical coherence tomography, and imaging with an original prototype AO SLO system. The AO SLO images showed many hyperreflective bundles suggesting nerve fiber bundles. In glaucomatous eyes, the nerve fiber bundles were narrower than in normal eyes, and the nerve fiber layer thickness was correlated with the nerve fiber bundle widths on AO SLO (P fiber layer defect area on fundus photography, the nerve fiber bundles on AO SLO were narrower compared with those in normal eyes (P optic disc, the nerve fiber bundle width was significantly lower, even in areas without nerve fiber layer defect, in eyes with glaucomatous eyes compared with normal eyes (P = .026). The mean deviations of each cluster in visual field testing were correlated with the corresponding nerve fiber bundle widths (P = .017). AO SLO images showed reduced nerve fiber bundle widths both in clinically normal and abnormal areas of glaucomatous eyes, and these abnormalities were associated with visual field defects, suggesting that AO SLO may be useful for detecting early nerve fiber bundle abnormalities associated with loss of visual function. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy in a zebrafish model of retinal vascular occlusion and remodeling

    Li, Xiaoyue; Spitz, Kathleen; Bozic, Ivan; Tao, Yuankai K.

    2018-02-01

    Neovascularization in diabetic retinopathy (DR) and age-related macular degeneration (AMD) result in severe vision-loss and are two of the leading causes of blindness. The structural, metabolic, and vascular changes underlying retinal neovascularization are unknown and, thus, there is an unmet need to identify mechanisms of pathogenesis and novel anti-angiogenic therapies. Zebrafish is a robust ophthalmological model because its retina has comparable structure to the human retina and its fecundity and life-cycle enable development of mutant phenotypes of human pathologies. Here, we perform multimodal imaging with OCT and fluorescence confocal scanning laser ophthalmoscopy (cSLO) to identify changes in retinal structure and function in a zebrafish model of vascular leakage. Transgenic zebrafish with EGFP tagged plasma protein were imaged longitudinally at six time points over two weeks to visualize vascular perfusion changes from diethylaminobenzaldehyde (DEAB) treatment. Complementary contrast from OCT-A perfusion maps and cSLO imaging of plasma protein EGFP shows vascular occlusions posttreatment. cSLO images confirm presence of vessels despite loss of OCT-A signal. Plasma protein EGFP contrast also shows significant changes in vessel structure as compared to baseline images. OCT structural volumes show empty vessel cross-sections confirming non-perfusion. In addition, we present algorithms for automated biometric identification of OCT datasets using OCT-A vascular patterns in the presence of significant vascular perfusion changes. These results establish a framework for large-scale in vivo assays to identify novel anti-angiogenic compounds and understand the mechanisms ofneovascularization associated with retinal ocular pathologies.

  8. Supersymmetric dark matter: Indirect detection

    Bergstroem, L.

    2000-01-01

    Dark matter detection experiments are improving to the point where they can detect or restrict the primary particle physics candidates for non baryonic dark matter. The methods for detection are usually categorized as direct, i.e., searching for signals caused by passage of dark matter particles in terrestrial detectors, or indirect. Indirect detection methods include searching for antimatter and gamma rays, in particular gamma ray lines, in cosmic rays and high-energy neutrinos from the centre of the Earth or Sun caused by accretion and annihilation of dark matter particles. A review is given of recent progress in indirect detection, both on the theoretical and experimental side

  9. The Complexity of Indirect Translation

    Wenjie, L. I.

    2017-01-01

    its complex nature, and thus determined that many facets of ITr remain to be studied. The present article will try to encompass the complexity of ITr by looking into the reasons for translating indirectly, the challenge of finding out mediating texts (MTs), indirectness in both translation...... of which have been translated and interpreted indirectly through major languages like English, will be employed as examples. Hopefully, this study will offer more insights into the nature of translation as a social activity and raise further interests in studying translation as a complex phenomenon....

  10. A simplified indirect bonding technique

    Radha Katiyar

    2014-01-01

    Full Text Available With the advent of lingual orthodontics, indirect bonding technique has become an integral part of practice. It involves placement of brackets initially on the models and then their transfer to teeth with the help of transfer trays. Problems encountered with current indirect bonding techniques used are (1 the possibility of adhesive flash remaining around the base of the brackets which requires removal (2 longer time required for the adhesive to gain enough bond strength for secure tray removal. The new simplified indirect bonding technique presented here overcomes both these problems.

  11. Binocular summation and other forms of non-dominant eye contribution in individuals with strabismic amblyopia during habitual viewing.

    Brendan T Barrett

    Full Text Available BACKGROUND: Adults with amblyopia ('lazy eye', long-standing strabismus (ocular misalignment or both typically do not experience visual symptoms because the signal from weaker eye is given less weight than the signal from its fellow. Here we examine the contribution of the weaker eye of individuals with strabismus and amblyopia with both eyes open and with the deviating eye in its anomalous motor position. METHODOLOGY/RESULTS: The task consisted of a blue-on-yellow detection task along a horizontal line across the central 50 degrees of the visual field. We compare the results obtained in ten individuals with strabismic amblyopia with ten visual normals. At each field location in each participant, we examined how the sensitivity exhibited under binocular conditions compared with sensitivity from four predictions, (i a model of binocular summation, (ii the average of the monocular sensitivities, (iii dominant-eye sensitivity or (iv non-dominant-eye sensitivity. The proportion of field locations for which the binocular summation model provided the best description of binocular sensitivity was similar in normals (50.6% and amblyopes (48.2%. Average monocular sensitivity matched binocular sensitivity in 14.1% of amblyopes' field locations compared to 8.8% of normals'. Dominant-eye sensitivity explained sensitivity at 27.1% of field locations in amblyopes but 21.2% in normals. Non-dominant-eye sensitivity explained sensitivity at 10.6% of field locations in amblyopes but 19.4% in normals. Binocular summation provided the best description of the sensitivity profile in 6/10 amblyopes compared to 7/10 of normals. In three amblyopes, dominant-eye sensitivity most closely reflected binocular sensitivity (compared to two normals and in the remaining amblyope, binocular sensitivity approximated to an average of the monocular sensitivities. CONCLUSIONS: Our results suggest a strong positive contribution in habitual viewing from the non-dominant eye in

  12. Monocular and binocular visual impairment in the UK Biobank study: prevalence, associations and diagnoses.

    McKibbin, Martin; Farragher, Tracey M; Shickle, Darren

    2018-01-01

    To determine the prevalence of, associations with and diagnoses leading to mild visual impairment or worse (logMAR >0.3) in middle-aged adults in the UK Biobank study. Prevalence estimates for monocular and binocular visual impairment were determined for the UK Biobank participants with fundus photographs and spectral domain optical coherence tomography images. Associations with socioeconomic, biometric, lifestyle and medical variables were investigated for cases with visual impairment and matched controls, using multinomial logistic regression models. Self-reported eye history and image grading results were used to identify the primary diagnoses leading to visual impairment for a sample of 25% of cases. For the 65 033 UK Biobank participants, aged 40-69 years and with fundus images, 6682 (10.3%) and 1677 (2.6%) had mild visual impairment or worse in one or both eyes, respectively. Increasing deprivation, age and ethnicity were independently associated with both monocular and binocular visual impairment. No primary diagnosis for the recorded level of visual impairment could be identified for 49.8% of eyes. The most common identifiable diagnoses leading to visual impairment were cataract, amblyopia, uncorrected refractive error and vitreoretinal interface abnormalities. The prevalence of visual impairment in the UK Biobank study cohort is lower than for population-based studies from other industrialised countries. Monocular and binocular visual impairment are associated with increasing deprivation, age and ethnicity. The UK Biobank dataset does not allow confident identification of the causes of visual impairment, and the results may not be applicable to the wider UK population.

  13. Short-term saccadic adaptation in the macaque monkey: a binocular mechanism

    Schultz, K. P.

    2013-01-01

    Saccadic eye movements are rapid transfers of gaze between objects of interest. Their duration is too short for the visual system to be able to follow their progress in time. Adaptive mechanisms constantly recalibrate the saccadic responses by detecting how close the landings are to the selected targets. The double-step saccadic paradigm is a common method to simulate alterations in saccadic gain. While the subject is responding to a first target shift, a second shift is introduced in the middle of this movement, which masks it from visual detection. The error in landing introduced by the second shift is interpreted by the brain as an error in the programming of the initial response, with gradual gain changes aimed at compensating the apparent sensorimotor mismatch. A second shift applied dichoptically to only one eye introduces disconjugate landing errors between the two eyes. A monocular adaptive system would independently modify only the gain of the eye exposed to the second shift in order to reestablish binocular alignment. Our results support a binocular mechanism. A version-based saccadic adaptive process detects postsaccadic version errors and generates compensatory conjugate gain alterations. A vergence-based saccadic adaptive process detects postsaccadic disparity errors and generates corrective nonvisual disparity signals that are sent to the vergence system to regain binocularity. This results in striking dynamical similarities between visually driven combined saccade-vergence gaze transfers, where the disparity is given by the visual targets, and the double-step adaptive disconjugate responses, where an adaptive disparity signal is generated internally by the saccadic system. PMID:23076111

  14. Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study.

    Katrin Sippel

    Full Text Available Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii to identify factors influencing the performance, and (iii to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP, and ten healthy-sighted control subjects (GC were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item. Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p < 0.001. Furthermore, patients who passed the task showed a significantly higher number of glances towards the visual field defect (VFD area than patients who failed (t-test, p < 0.05. According to these results, glaucoma patients with defects in the binocular visual field display on average longer search times in a naturalistic supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

  15. Monocular and binocular visual impairment in the UK Biobank study: prevalence, associations and diagnoses

    Farragher, Tracey M; Shickle, Darren

    2018-01-01

    Objective To determine the prevalence of, associations with and diagnoses leading to mild visual impairment or worse (logMAR >0.3) in middle-aged adults in the UK Biobank study. Methods and analysis Prevalence estimates for monocular and binocular visual impairment were determined for the UK Biobank participants with fundus photographs and spectral domain optical coherence tomography images. Associations with socioeconomic, biometric, lifestyle and medical variables were investigated for cases with visual impairment and matched controls, using multinomial logistic regression models. Self-reported eye history and image grading results were used to identify the primary diagnoses leading to visual impairment for a sample of 25% of cases. Results For the 65 033 UK Biobank participants, aged 40–69 years and with fundus images, 6682 (10.3%) and 1677 (2.6%) had mild visual impairment or worse in one or both eyes, respectively. Increasing deprivation, age and ethnicity were independently associated with both monocular and binocular visual impairment. No primary diagnosis for the recorded level of visual impairment could be identified for 49.8% of eyes. The most common identifiable diagnoses leading to visual impairment were cataract, amblyopia, uncorrected refractive error and vitreoretinal interface abnormalities. Conclusions The prevalence of visual impairment in the UK Biobank study cohort is lower than for population-based studies from other industrialised countries. Monocular and binocular visual impairment are associated with increasing deprivation, age and ethnicity. The UK Biobank dataset does not allow confident identification of the causes of visual impairment, and the results may not be applicable to the wider UK population. PMID:29657974

  16. The iPod binocular home-based treatment for amblyopia in adults: efficacy and compliance.

    Hess, Robert F; Babu, Raiju Jacob; Clavagnier, Simon; Black, Joanna; Bobier, William; Thompson, Benjamin

    2014-09-01

    Occlusion therapy for amblyopia is predicated on the idea that amblyopia is primarily a disorder of monocular vision; however, there is growing evidence that patients with amblyopia have a structurally intact binocular visual system that is rendered functionally monocular due to suppression. Furthermore, we have found that a dichoptic treatment intervention designed to directly target suppression can result in clinically significant improvement in both binocular and monocular visual function in adult patients with amblyopia. The fact that monocular improvement occurs in the absence of any fellow eye occlusion suggests that amblyopia is, in part, due to chronic suppression. Previously the treatment has been administered as a psychophysical task and more recently as a video game that can be played on video goggles or an iPod device equipped with a lenticular screen. The aim of this case-series study of 14 amblyopes (six strabismics, six anisometropes and two mixed) ages 13 to 50 years was to investigate: 1. whether the portable video game treatment is suitable for at-home use and 2. whether an anaglyphic version of the iPod-based video game, which is more convenient for at-home use, has comparable effects to the lenticular version. The dichoptic video game treatment was conducted at home and visual functions assessed before and after treatment. We found that at-home use for 10 to 30 hours restored simultaneous binocular perception in 13 of 14 cases along with significant improvements in acuity (0.11 ± 0.08 logMAR) and stereopsis (0.6 ± 0.5 log units). Furthermore, the anaglyph and lenticular platforms were equally effective. In addition, the iPod devices were able to record a complete and accurate picture of treatment compliance. The home-based dichoptic iPod approach represents a viable treatment for adults with amblyopia. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometrists Association Australia.

  17. The logic of indirect speech

    Pinker, Steven; Nowak, Martin A.; Lee, James J.

    2008-01-01

    When people speak, they often insinuate their intent indirectly rather than stating it as a bald proposition. Examples include sexual come-ons, veiled threats, polite requests, and concealed bribes. We propose a three-part theory of indirect speech, based on the idea that human communication involves a mixture of cooperation and conflict. First, indirect requests allow for plausible deniability, in which a cooperative listener can accept the request, but an uncooperative one cannot react adversarially to it. This intuition is supported by a game-theoretic model that predicts the costs and benefits to a speaker of direct and indirect requests. Second, language has two functions: to convey information and to negotiate the type of relationship holding between speaker and hearer (in particular, dominance, communality, or reciprocity). The emotional costs of a mismatch in the assumed relationship type can create a need for plausible deniability and, thereby, select for indirectness even when there are no tangible costs. Third, people perceive language as a digital medium, which allows a sentence to generate common knowledge, to propagate a message with high fidelity, and to serve as a reference point in coordination games. This feature makes an indirect request qualitatively different from a direct one even when the speaker and listener can infer each other's intentions with high confidence. PMID:18199841

  18. Assessment of β-zone peripapillary atrophy by optical coherence tomography and scanning laser ophthalmoscopy imaging in glaucoma patients

    Seidensticker F

    2014-06-01

    Full Text Available Florian Seidensticker,1,* Lukas Reznicek,2,* Thomas Mann,2 Irene Hübert,2 Anselm Kampik,2 Michael Ulbig,2 Christoph Hirneiss,2 Aljoscha S Neubauer,2 Marcus Kernt2 1Department of Ophthalmology, Hannover Medical School, Hannover, Germany; 2Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany  *These authors have contributed equally to this work Purpose: To assess β-zone peripapillary atrophy (β-PPA using spectral domain optical coherence tomography (SD-OCT, scanning laser ophthalmoscopy (SLO, and fundus autofluorescence (FAF imaging in patients with primary open-angle glaucoma with advanced glaucomatous visual field defects. Methods: A consecutive, prospective series of 82 study eyes with primary open-angle glaucoma were included in this study. All study participants underwent a full ophthalmic examination followed by SD-OCT, wide-field SLO, and FAF imaging of the optic nerve head and the peripapillary region. Results: Eighty-four glaucomatous eyes were included in our prospective study. Correlation analyses for horizontally and vertically obtained β-PPA for all three imaging modalities (color SLO, FAF, and SD-OCT revealed highest correlations between FAF and color SLO (Pearson correlation coefficient: 0.904 [P<0.001] for horizontal β-PPA and 0.786 [P<0.001] for vertical β-PPA. Bland–Altman plotting revealed highest agreements between color SLO and FAF, with −2.1 pixels ±1.96 standard deviation (SD for horizontal β-PPA, SD: 10.5 pixels and 2.4 pixels ±1.96 SD for vertical β-PPA. Conclusion: β-PPA can be assessed using en-face SLO and cross-sectional SD-OCT imaging. Correlation analyses revealed highest correlations between color SLO and FAF imaging, while correlations between SLO and SD-OCT were weak. A more precise structural definition of β-PPA is needed. Keywords: fundus autofluorescence, FAF, OCT, SD-OCT, SLO, glaucomatous optic neuropathy

  19. Binocular optical axis parallelism detection precision analysis based on Monte Carlo method

    Ying, Jiaju; Liu, Bingqi

    2018-02-01

    According to the working principle of the binocular photoelectric instrument optical axis parallelism digital calibration instrument, and in view of all components of the instrument, the various factors affect the system precision is analyzed, and then precision analysis model is established. Based on the error distribution, Monte Carlo method is used to analyze the relationship between the comprehensive error and the change of the center coordinate of the circle target image. The method can further guide the error distribution, optimize control the factors which have greater influence on the comprehensive error, and improve the measurement accuracy of the optical axis parallelism digital calibration instrument.

  20. Do we really know the prevalence of accomodative and nonstrabismic binocular dysfunctions?

    Pilar Cacho-Martínez

    2010-10-01

    Conclusion: There is a lack of proper epidemiological studies about the prevalence of accommodative and nonstrabismic binocular anomalies. Studies reviewed examine consecutive or selected patients in clinical settings and schools but in any case they are randomized and representative of their populations with no data for general population. The wide discrepancies in prevalence figures are due to both sample population and the lack of uniformity in diagnostic criteria so that it makes difficult to compile results. Biases and limitations of reports determine that prevalence rates offered are only estimations from selected populations.

  1. Importância da visão binocular no desempenho da leitura em crianças

    Lança, Carla Costa

    2012-01-01

    Objectivos do estudo: 1) identificar os movimentos oculares envolvidos na leitura e (2) descrever a influência das anomalias da visão binocular no desempenho da leitura em crianças. Metodologia: estudo descritivo baseado numa revisão de literatura. Foi efetuada uma pesquisa de referências publicadas até 2011, acessíveis através da PubMed, da Science Direct e de outras fontes adicionais. Os seguintes termos foram utilizados na pesquisa: binocular vision AND reading; ocular mo...

  2. Indirect Reciprocity; A Field Experiment.

    van Apeldoorn, Jacobien; Schram, Arthur

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has been widely studied theoretically, the empirical evidence of indirect reciprocity has thus far been limited and based solely on behavior in laboratory experiments. We provide evidence from an online environment where members can repeatedly ask and offer services to each other, free of charge. For the purpose of this study we created several new member profiles, which differ only in terms of their serving history. We then sent out a large number of service requests to different members from all over the world. We observe that a service request is more likely to be rewarded for those with a profile history of offering the service (to third parties) in the past. This provides clear evidence of (downstream) indirect reciprocity. We find no support for upstream indirect reciprocity (in this case, rewarding the service request after having previously received the service from third parties), however. Our evidence of downstream indirect reciprocity cannot be attributed to reputational effects concerning one's trustworthiness as a service user.

  3. Indirect Reciprocity under Incomplete Observation

    Nakamura, Mitsuhiro; Masuda, Naoki

    2011-01-01

    Indirect reciprocity, in which individuals help others with a good reputation but not those with a bad reputation, is a mechanism for cooperation in social dilemma situations when individuals do not repeatedly interact with the same partners. In a relatively large society where indirect reciprocity is relevant, individuals may not know each other's reputation even indirectly. Previous studies investigated the situations where individuals playing the game have to determine the action possibly without knowing others' reputations. Nevertheless, the possibility that observers of the game, who generate the reputation of the interacting players, assign reputations without complete information about them has been neglected. Because an individual acts as an interacting player and as an observer on different occasions if indirect reciprocity is endogenously sustained in a society, the incompleteness of information may affect either role. We examine the game of indirect reciprocity when the reputations of players are not necessarily known to observers and to interacting players. We find that the trustful discriminator, which cooperates with good and unknown players and defects against bad players, realizes cooperative societies under seven social norms. Among the seven social norms, three of the four suspicious norms under which cooperation (defection) to unknown players leads to a good (bad) reputation enable cooperation down to a relatively small observation probability. In contrast, the three trustful norms under which both cooperation and defection to unknown players lead to a good reputation are relatively efficient. PMID:21829335

  4. How Simultaneous is the Perception of Binocular Depth and Rivalry in Plaid Stimuli?

    Athena Buckthought

    2012-06-01

    Full Text Available Psychophysical experiments have demonstrated that it is possible to perceive both binocular depth and rivalry in plaids (Buckthought and Wilson 2007, Vision Research 47 2543–2556. In a recent study, we investigated the neural substrates for depth and rivalry processing with these plaid patterns, when either a depth or rivalry task was performed (Buckthought and Mendola 2011, Journal of Vision 11 1–15. However, the extent to which perception of the two stimulus aspects was truly simultaneous remained somewhat unclear. In the present study, we introduced a new task in which subjects were instructed to perform both depth and rivalry tasks concurrently. Subjects were clearly able to perform both tasks at the same time, but with a modest, symmetric drop in performance when compared to either task carried out alone. Subjects were also able to raise performance levels for either task by performing it with a higher priority, with a decline in performance for the other task. The symmetric declines in performance are consistent with the interpretation that the two tasks are equally demanding of attention (Braun and Julesz 1998, Perception & Psychophysics 60 1–23. The results demonstrate the impressive combination of binocular features that supports coincident depth and rivalry in surface perception, within the constraints of presumed orientation and spatial frequency channels.

  5. Measurement of the geometric parameters of power contact wire based on binocular stereovision

    Pan, Xue-Tao; Zhang, Ya-feng; Meng, Fei

    2010-10-01

    In the electrified railway power supply system, electric locomotive obtains power from the catenary's wire through the pantograph. Under the action of the pantograph, combined with various factors such as vibration, touch current, relative sliding speed, load, etc, the contact wire will produce mechanical wear and electrical wear. Thus, in electrified railway construction and daily operations, the geometric parameters such as line height, pull value, the width of wear surface must be under real-timely and non-contact detection. On the one hand, the safe operation of electric railways will be guaranteed; on the other hand, the wire endurance will be extended, and operating costs reduced. Based on the characteristics of the worn wires' image signal, the binocular stereo vision technology was applied for measurement of contact wire geometry parameters, a mathematical model of measurement of geometric parameters was derived, and the boundaries of the wound wire abrasion-point value were extracted by means of sub-pixel edge detection method based on the LOG operator with the least-squares fitting, thus measurements of the wire geometry parameters were realized. Principles were demonstrated through simulation experiments, and the experimental results show that the detection methods presented in this paper for measuring the accuracy, efficiency and convenience, etc. are close to or superior to the traditional measurements, which has laid a good foundation for the measurement system of geometric parameters for the contact wire of the development of binocular vision.

  6. An exploratory study: prolonged periods of binocular stimulation can provide an effective treatment for childhood amblyopia.

    Knox, Pamela J; Simmers, Anita J; Gray, Lyle S; Cleary, Marie

    2012-02-21

    The purpose of the present study was to explore the potential for treating childhood amblyopia with a binocular stimulus designed to correlate the visual input from both eyes. Eight strabismic, two anisometropic, and four strabismic and anisometropic amblyopes (mean age, 8.5 ± 2.6 years) undertook a dichoptic perceptual learning task for five sessions (each lasting 1 hour) over the course of a week. The training paradigm involved a simple computer game, which required the subject to use both eyes to perform the task. A statistically significant improvement (t(₁₃) = 5.46; P = 0.0001) in the mean visual acuity (VA) of the amblyopic eye (AE) was demonstrated, from 0.51 ± 0.27 logMAR before training to 0.42 ± 0.28 logMAR after training with six subjects gaining 0.1 logMAR or more of improvement. Measurable stereofunction was established for the first time in three subjects with an overall significant mean improvement in stereoacuity after training (t(₁₃) =2.64; P = 0.02). The dichoptic-based perceptual learning therapy employed in the present study improved both the monocular VA of the AE and stereofunction, verifying the feasibility of a binocular approach in the treatment of childhood amblyopia.

  7. Research on key technology of yacht positioning based on binocular parallax

    Wang, Wei; Wei, Ping; Liu, Zengzhi

    2016-10-01

    Yacht has become a fashionable way for entertainment. However, to obtain the precise location of a yacht docked at a port has become one of the concerns of a yacht manager. To deal with this issue, we adopt a positioning method based on the principle of binocular parallax and background difference in this paper. Binocular parallax uses cameras to get multi-dimensional perspective of the yacht based on geometric principle of imaging. In order to simplify the yacht localization problem, we install LED light indicator as the key point on a yacht. And let it flash at a certain frequency during day time and night time. After getting the distance between the LED and the cameras, locating the yacht is easy. Compared with other traditional positioning methods, this method is simpler and easier to implement. In this paper, we study the yacht positioning method using the LED indicator. Simulation experiment is done for a yacht model in the distance of 3 meters. The experimental result shows that our method is feasible and easy to implement with a small 15% positioning error.

  8. A new computerized diagnostic algorithm for quantitative evaluation of binocular misalignment in patients with strabismus

    Nam, Kyoung Won; Kim, In Young; Kang, Ho Chul; Yang, Hee Kyung; Yoon, Chang Ki; Hwang, Jeong Min; Kim, Young Jae; Kim, Tae Yun; Kim, Kwang Gi

    2012-10-01

    Accurate measurement of binocular misalignment between both eyes is important for proper preoperative management, surgical planning, and postoperative evaluation of patients with strabismus. In this study, we proposed a new computerized diagnostic algorithm that can calculate the angle of binocular eye misalignment photographically by using a dedicated three-dimensional eye model mimicking the structure of the natural human eye. To evaluate the performance of the proposed algorithm, eight healthy volunteers and eight individuals with strabismus were recruited in this study, the horizontal deviation angle, vertical deviation angle, and angle of eye misalignment were calculated and the angular differences between the healthy and the strabismus groups were evaluated using the nonparametric Mann-Whitney test and the Pearson correlation test. The experimental results demonstrated a statistically significant difference between the healthy and strabismus groups (p = 0.015 0.05). The measurements of the two methods were highly correlated (r = 0.969, p human eye to diagnose non-invasively the severity of strabismus.

  9. Sensor assembly method using silicon interposer with trenches for three-dimensional binocular range sensors

    Nakajima, Kazuhiro; Yamamoto, Yuji; Arima, Yutaka

    2018-04-01

    To easily assemble a three-dimensional binocular range sensor, we devised an alignment method for two image sensors using a silicon interposer with trenches. The trenches were formed using deep reactive ion etching (RIE) equipment. We produced a three-dimensional (3D) range sensor using the method and experimentally confirmed that sufficient alignment accuracy was realized. It was confirmed that the alignment accuracy of the two image sensors when using the proposed method is more than twice that of the alignment assembly method on a conventional board. In addition, as a result of evaluating the deterioration of the detection performance caused by the alignment accuracy, it was confirmed that the vertical deviation between the corresponding pixels in the two image sensors is substantially proportional to the decrease in detection performance. Therefore, we confirmed that the proposed method can realize more than twice the detection performance of the conventional method. Through these evaluations, the effectiveness of the 3D binocular range sensor aligned by the silicon interposer with the trenches was confirmed.

  10. Research and Development of Target Recognition and Location Crawling Platform based on Binocular Vision

    Xu, Weidong; Lei, Zhu; Yuan, Zhang; Gao, Zhenqing

    2018-03-01

    The application of visual recognition technology in industrial robot crawling and placing operation is one of the key tasks in the field of robot research. In order to improve the efficiency and intelligence of the material sorting in the production line, especially to realize the sorting of the scattered items, the robot target recognition and positioning crawling platform based on binocular vision is researched and developed. The images were collected by binocular camera, and the images were pretreated. Harris operator was used to identify the corners of the images. The Canny operator was used to identify the images. Hough-chain code recognition was used to identify the images. The target image in the image, obtain the coordinates of each vertex of the image, calculate the spatial position and posture of the target item, and determine the information needed to capture the movement and transmit it to the robot control crawling operation. Finally, In this paper, we use this method to experiment the wrapping problem in the express sorting process The experimental results show that the platform can effectively solve the problem of sorting of loose parts, so as to achieve the purpose of efficient and intelligent sorting.

  11. Optoelectronic stereoscopic device for diagnostics, treatment, and developing of binocular vision

    Pautova, Larisa; Elkhov, Victor A.; Ovechkis, Yuri N.

    2003-08-01

    Operation of the device is based on alternative generation of pictures for left and right eyes on the monitor screen. Controller gives pulses on LCG so that shutter for left or right eye opens synchronously with pictures. The device provides frequency of switching more than 100 Hz, and that is why the flickering is absent. Thus, a separate demonstration of images to the left eye or to the right one in turn is obtained for patients being unaware and creates the conditions of binocular perception clsoe to natural ones without any additional separation of vision fields. LC-cell transfer characteristic coodination with time parameters of monitor screen has enabled to improve stereo image quality. Complicated problem of computer stereo images with LC-glasses is so called 'ghosts' - noise images that come to blocked eye. We reduced its influence by adapting stereo images to phosphor and LC-cells characteristics. The device is intended for diagnostics and treatment of stabismus, amblyopia and other binocular and stereoscopic vision impairments, for cultivating, training and developing of stereoscopic vision, for measurements of horizontal and vertical phoria, phusion reserves, the stereovision acuity and some else, for fixing central scotoma borders, as well as suppression scotoma in strabismus too.

  12. Binocular glaucomatous visual field loss and its impact on visual exploration--a supermarket study.

    Sippel, Katrin; Kasneci, Enkelejda; Aehling, Kathrin; Heister, Martin; Rosenstiel, Wolfgang; Schiefer, Ulrich; Papageorgiou, Elena

    2014-01-01

    Advanced glaucomatous visual field loss may critically interfere with quality of life. The purpose of this study was to (i) assess the impact of binocular glaucomatous visual field loss on a supermarket search task as an example of everyday living activities, (ii) to identify factors influencing the performance, and (iii) to investigate the related compensatory mechanisms. Ten patients with binocular glaucoma (GP), and ten healthy-sighted control subjects (GC) were asked to collect twenty different products chosen randomly in two supermarket racks as quickly as possible. The task performance was rated as "passed" or "failed" with regard to the time per correctly collected item. Based on the performance of control subjects, the threshold value for failing the task was defined as μ+3σ (in seconds per correctly collected item). Eye movements were recorded by means of a mobile eye tracker. Eight out of ten patients with glaucoma and all control subjects passed the task. Patients who failed the task needed significantly longer time (111.47 s ±12.12 s) to complete the task than patients who passed (64.45 s ±13.36 s, t-test, p supermarket task. However, a considerable number of patients, who compensate by frequent glancing towards the VFD, showed successful task performance. Therefore, systematic exploration of the VFD area seems to be a "time-effective" compensatory mechanism during the present supermarket task.

  13. Full-reference quality assessment of stereoscopic images by learning binocular receptive field properties.

    Shao, Feng; Li, Kemeng; Lin, Weisi; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

    2015-10-01

    Quality assessment of 3D images encounters more challenges than its 2D counterparts. Directly applying 2D image quality metrics is not the solution. In this paper, we propose a new full-reference quality assessment for stereoscopic images by learning binocular receptive field properties to be more in line with human visual perception. To be more specific, in the training phase, we learn a multiscale dictionary from the training database, so that the latent structure of images can be represented as a set of basis vectors. In the quality estimation phase, we compute sparse feature similarity index based on the estimated sparse coefficient vectors by considering their phase difference and amplitude difference, and compute global luminance similarity index by considering luminance changes. The final quality score is obtained by incorporating binocular combination based on sparse energy and sparse complexity. Experimental results on five public 3D image quality assessment databases demonstrate that in comparison with the most related existing methods, the devised algorithm achieves high consistency with subjective assessment.

  14. Parts-based stereoscopic image assessment by learning binocular manifold color visual properties

    Xu, Haiyong; Yu, Mei; Luo, Ting; Zhang, Yun; Jiang, Gangyi

    2016-11-01

    Existing stereoscopic image quality assessment (SIQA) methods are mostly based on the luminance information, in which color information is not sufficiently considered. Actually, color is part of the important factors that affect human visual perception, and nonnegative matrix factorization (NMF) and manifold learning are in line with human visual perception. We propose an SIQA method based on learning binocular manifold color visual properties. To be more specific, in the training phase, a feature detector is created based on NMF with manifold regularization by considering color information, which not only allows parts-based manifold representation of an image, but also manifests localized color visual properties. In the quality estimation phase, visually important regions are selected by considering different human visual attention, and feature vectors are extracted by using the feature detector. Then the feature similarity index is calculated and the parts-based manifold color feature energy (PMCFE) for each view is defined based on the color feature vectors. The final quality score is obtained by considering a binocular combination based on PMCFE. The experimental results on LIVE I and LIVE Π 3-D IQA databases demonstrate that the proposed method can achieve much higher consistency with subjective evaluations than the state-of-the-art SIQA methods.

  15. Decoding conjunctions of direction-of-motion and binocular disparity from human visual cortex.

    Seymour, Kiley J; Clifford, Colin W G

    2012-05-01

    Motion and binocular disparity are two features in our environment that share a common correspondence problem. Decades of psychophysical research dedicated to understanding stereopsis suggest that these features interact early in human visual processing to disambiguate depth. Single-unit recordings in the monkey also provide evidence for the joint encoding of motion and disparity across much of the dorsal visual stream. Here, we used functional MRI and multivariate pattern analysis to examine where in the human brain conjunctions of motion and disparity are encoded. Subjects sequentially viewed two stimuli that could be distinguished only by their conjunctions of motion and disparity. Specifically, each stimulus contained the same feature information (leftward and rightward motion and crossed and uncrossed disparity) but differed exclusively in the way these features were paired. Our results revealed that a linear classifier could accurately decode which stimulus a subject was viewing based on voxel activation patterns throughout the dorsal visual areas and as early as V2. This decoding success was conditional on some voxels being individually sensitive to the unique conjunctions comprising each stimulus, thus a classifier could not rely on independent information about motion and binocular disparity to distinguish these conjunctions. This study expands on evidence that disparity and motion interact at many levels of human visual processing, particularly within the dorsal stream. It also lends support to the idea that stereopsis is subserved by early mechanisms also tuned to direction of motion.

  16. Adaptive optics ophthalmoscopy.

    Roorda, Austin; Duncan, Jacque L

    2015-11-01

    This review starts with a brief history and description of adaptive optics (AO) technology, followed by a showcase of the latest capabilities of AO systems for imaging the human retina and an extensive review of the literature on where AO is being used clinically. The review concludes with a discussion on future directions and guidance on usage and interpretation of images from AO systems for the eye.

  17. Adaptive optics ophthalmoscopy

    Roorda, Austin; Duncan, Jacque L.

    2015-01-01

    This review starts with a brief history and description of adaptive optics (AO) technology, followed by a showcase of the latest capabilities of AO systems for imaging the human retina and an extensive review of the literature on where AO is being used clinically. The review concludes with a discussion on future directions and guidance on usage and interpretation of images from AO systems for the eye.

  18. Indirect techniques in nuclear astrophysics

    Mukhamedzhanov, A.M.; Tribble, R.E.; Blokhintsev, L.D.; Cherubini, S.; Spitaleri, C.; Kroha, V.; Nunes, F.M.

    2005-01-01

    It is very difficult or often impossible to measure in the lab conditions nuclear cross sections at astrophysically relevant energies. That is why different indirect techniques are used to extract astrophysical information. In this talk different experimental possibilities to get astrophysical information using radioactive and stable beams will be addressed. 1. The asymptotic normalization coefficient (ANC) method. 2. Radiative neutron captures are determined by the spectroscopic factors (SP). A new experimental technique to determine the neutron SPs will be addressed. 3. 'Trojan Horse' is another unique indirect method, which allows one to extract the astrophysical factors for direct and resonant nuclear reactions at astrophysically relevant energies. (author)

  19. Environmental effects of indirect subsidies

    Van Beers, C.P.; De Moor, A.P.G.; Van den Bergh, J.C.J.M.; Oosterhuis, F.H.

    2003-01-01

    The aim of the study on the title subject is to develop a transparent integrated method to determine and analyze the environmental impacts of indirect subsidies, applied in the sectors agriculture, energy, mobility, and tourism. From the results it appears that the hazardous effects of subsidies are big. Examples are milk, the regulating energy levy, and kerosene [nl

  20. Indirect searches for dark matter

    The current status of indirect searches for dark matter has been reviewed in a schematic way here. The main relevant experimental results of the recent years have been listed and the excitements and disappointments that their phenomenological interpretations in terms of almost-standard annihilating dark matter have ...

  1. Indirect methods in nuclear astrophysics

    Bertulani, C.A.; Shubhchintak; Mukhamedzhanov, A.; Kadyrov, A. S.; Kruppa, A.; Pang, D. Y.

    2016-01-01

    We discuss recent developments in indirect methods used in nuclear astrophysics to determine the capture cross sections and subsequent rates of various stellar burning processes, when it is difficult to perform the corresponding direct measurements. We discuss in brief, the basic concepts of Asymptotic Normalization Coefficients, the Trojan Horse Method, the Coulomb Dissociation Method, (d,p), and charge-exchange reactions. (paper)

  2. Indirect Reciprocity : A Field Experiment

    van Apeldoorn, J.; Schram, A.

    2016-01-01

    Indirect reciprocity involves cooperative acts towards strangers, either in response to their kindness to third parties (downstream) or after receiving kindness from others oneself (upstream). It is considered to be important for the evolution of cooperative behavior amongst humans. Though it has

  3. Indirect reciprocity with optional interactions.

    Ghang, Whan; Nowak, Martin A

    2015-01-21

    Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Evaluation of a four month rehabilitation program for stroke patients with balance problems and binocular visual dysfunction

    Schow, Trine; Harris, Paul; Teasdale, Thomas William

    2016-01-01

    Trine Schow, Paul Harris, Thomas William Teasdale, Morten Arendt Rasmussen. Evaluation of a four month rehabilitation program for stroke patients with balance problems and binocular visual dysfunction. NeuroRehabilitation. 2016 Apr 6;38(4):331-41. doi: 10.3233/NRE-161324....

  5. The minimum test battery to screen for binocular vision anomalies: report 3 of the BAND study.

    Hussaindeen, Jameel Rizwana; Rakshit, Archayeeta; Singh, Neeraj Kumar; Swaminathan, Meenakshi; George, Ronnie; Kapur, Suman; Scheiman, Mitchell; Ramani, Krishna Kumar

    2018-03-01

    This study aims to report the minimum test battery needed to screen non-strabismic binocular vision anomalies (NSBVAs) in a community set-up. When large numbers are to be screened we aim to identify the most useful test battery when there is no opportunity for a more comprehensive and time-consuming clinical examination. The prevalence estimates and normative data for binocular vision parameters were estimated from the Binocular Vision Anomalies and Normative Data (BAND) study, following which cut-off estimates and receiver operating characteristic curves to identify the minimum test battery have been plotted. In the receiver operating characteristic phase of the study, children between nine and 17 years of age were screened in two schools in the rural arm using the minimum test battery, and the prevalence estimates with the minimum test battery were found. Receiver operating characteristic analyses revealed that near point of convergence with penlight and red filter (> 7.5 cm), monocular accommodative facility ( 1.25 prism dioptres) were significant factors with cut-off values for best sensitivity and specificity. This minimum test battery was applied to a cohort of 305 children. The mean (standard deviation) age of the subjects was 12.7 (two) years with 121 males and 184 females. Using the minimum battery of tests obtained through the receiver operating characteristic analyses, the prevalence of NSBVAs was found to be 26 per cent. Near point of convergence with penlight and red filter > 10 cm was found to have the highest sensitivity (80 per cent) and specificity (73 per cent) for the diagnosis of convergence insufficiency. For the diagnosis of accommodative infacility, monocular accommodative facility with a cut-off of less than seven cycles per minute was the best predictor for screening (92 per cent sensitivity and 90 per cent specificity). The minimum test battery of near point of convergence with penlight and red filter, difference between distance and near

  6. Inability to perform posterior segment monitoring by scanning laser ophthalmoscopy or optical coherence tomography with some occlusive intraocular lenses in clinical use.

    Yusuf, Imran H; Peirson, Stuart N; Patel, Chetan K

    2012-03-01

    To evaluate whether occlusive intraocular lenses (IOLs) produced by several manufacturers for clinical use equivalently transmit near-infrared (IR) light for scanning laser ophthalmoscopy (SLO) or optical coherence tomography (OCT) imaging. Nuffield Laboratory of Ophthalmology, Oxford University, United Kingdom. Evaluation of diagnostic test or technology. The study evaluated 6 black IOLs of 2 designs: 3 poly(methyl methacrylate) (PMMA) and 3 iris-claw anterior chamber IOLs. Each IOL was placed between a broad-spectrum white light source and a spectroradiometer to generate transmission spectra. Transmission in the near-IR range was examined using an 850 nm light-emitting diode. Scanning laser ophthalmoscopy or OCT imaging using Spectralis spectral-domain SLO or OCT was attempted through occlusive IOLs in a model eye. Artisan iris-claw and MS 612 PMMA occlusive IOLs totally occluded all wavelengths of light, including in the near IR range in which SLO and OCT imaging systems operate. It was not possible to capture SLO or OCT images through the iris-claw and PMMA occlusive IOLs in a model eye. Results suggest the property of near-IR transmission that permits SLO or OCT imaging through occlusive IOLs is restricted to the Morcher range of occlusive IOLs. Patients with non-near IR transmitting IOLs will not be able to receive detailed posterior segment monitoring with SLO or OCT. This finding may have a significant impact on preoperative occlusive IOL selection and the management of current patients with occlusive IOLs. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  7. Indirect taxation in the European Union

    Ene, Sebastian; Micuda, Dan

    2007-01-01

    Indirect taxes are levied on the production and consumption of goods and services. They influence the retail price, and hence affect patterns of trade and consumption. Indirect taxes are ultimately paid by the final consumer. Sales and turnover taxes, excise duties and tariffs are the basic indirect taxes. In contrast with direct taxes, indirect taxes are seldom progressive. The principles for the levying of these taxes will be considered before the analysis of indirect taxes.

  8. AN AUTONOMOUS GPS-DENIED UNMANNED VEHICLE PLATFORM BASED ON BINOCULAR VISION FOR PLANETARY EXPLORATION

    M. Qin

    2018-04-01

    Full Text Available Vision-based navigation has become an attractive solution for autonomous navigation for planetary exploration. This paper presents our work of designing and building an autonomous vision-based GPS-denied unmanned vehicle and developing an ARFM (Adaptive Robust Feature Matching based VO (Visual Odometry software for its autonomous navigation. The hardware system is mainly composed of binocular stereo camera, a pan-and tilt, a master machine, a tracked chassis. And the ARFM-based VO software system contains four modules: camera calibration, ARFM-based 3D reconstruction, position and attitude calculation, BA (Bundle Adjustment modules. Two VO experiments were carried out using both outdoor images from open dataset and indoor images captured by our vehicle, the results demonstrate that our vision-based unmanned vehicle is able to achieve autonomous localization and has the potential for future planetary exploration.

  9. An Autonomous Gps-Denied Unmanned Vehicle Platform Based on Binocular Vision for Planetary Exploration

    Qin, M.; Wan, X.; Shao, Y. Y.; Li, S. Y.

    2018-04-01

    Vision-based navigation has become an attractive solution for autonomous navigation for planetary exploration. This paper presents our work of designing and building an autonomous vision-based GPS-denied unmanned vehicle and developing an ARFM (Adaptive Robust Feature Matching) based VO (Visual Odometry) software for its autonomous navigation. The hardware system is mainly composed of binocular stereo camera, a pan-and tilt, a master machine, a tracked chassis. And the ARFM-based VO software system contains four modules: camera calibration, ARFM-based 3D reconstruction, position and attitude calculation, BA (Bundle Adjustment) modules. Two VO experiments were carried out using both outdoor images from open dataset and indoor images captured by our vehicle, the results demonstrate that our vision-based unmanned vehicle is able to achieve autonomous localization and has the potential for future planetary exploration.

  10. An Active System for Visually-Guided Reaching in 3D across Binocular Fixations

    Ester Martinez-Martin

    2014-01-01

    Full Text Available Based on the importance of relative disparity between objects for accurate hand-eye coordination, this paper presents a biological approach inspired by the cortical neural architecture. So, the motor information is coded in egocentric coordinates obtained from the allocentric representation of the space (in terms of disparity generated from the egocentric representation of the visual information (image coordinates. In that way, the different aspects of the visuomotor coordination are integrated: an active vision system, composed of two vergent cameras; a module for the 2D binocular disparity estimation based on a local estimation of phase differences performed through a bank of Gabor filters; and a robotic actuator to perform the corresponding tasks (visually-guided reaching. The approach’s performance is evaluated through experiments on both simulated and real data.

  11. Semantic Edge Based Disparity Estimation Using Adaptive Dynamic Programming for Binocular Sensors.

    Zhu, Dongchen; Li, Jiamao; Wang, Xianshun; Peng, Jingquan; Shi, Wenjun; Zhang, Xiaolin

    2018-04-03

    Disparity calculation is crucial for binocular sensor ranging. The disparity estimation based on edges is an important branch in the research of sparse stereo matching and plays an important role in visual navigation. In this paper, we propose a robust sparse stereo matching method based on the semantic edges. Some simple matching costs are used first, and then a novel adaptive dynamic programming algorithm is proposed to obtain optimal solutions. This algorithm makes use of the disparity or semantic consistency constraint between the stereo images to adaptively search parameters, which can improve the robustness of our method. The proposed method is compared quantitatively and qualitatively with the traditional dynamic programming method, some dense stereo matching methods, and the advanced edge-based method respectively. Experiments show that our method can provide superior performance on the above comparison.

  12. Early visual responses predict conscious face perception within and between subjects during binocular rivalry

    Sandberg, Kristian; Bahrami, Bahador; Kanai, Ryota

    2013-01-01

    Previous studies indicate that conscious face perception may be related to neural activity in a large time window around 170–800 msec after stimulus presentation, yet in the majority of these studies changes in conscious experience are confounded with changes in physical stimulation. Using...... multivariate classification on MEG data recorded when participants reported changes in conscious perception evoked by binocular rivalry between a face and a grating, we showed that only MEG signals in the 120–320 msec time range, peaking at the M170 around 180 msec and the P2m at around 260 msec, reliably...... activity associated with conscious face perception generalized from one participant to another around the times of maximum prediction accuracy. Our work thus demonstrates that the neural correlates of particular conscious contents (here, faces) are highly consistent in time and space within individuals...

  13. Electronic Commerce and Indirect Taxation

    Watanabe, Satoshi

    2001-01-01

    This paper considers the reason why indirect tax issues arise in the context of electronic commerce and discusses relevant issues. To do so, the paper presents a simple framework to understand and examine these issues in the international context. It also identifies common and different issues of the VAT system and the RST system. It demonstrates that an emerging solution proposed in the context of the VAT system can be affected with difficult problems that were regarded to be problems of the...

  14. A Randomized Trial of a Binocular iPad Game Versus Part-Time Patching in Children Aged 13 to 16 Years With Amblyopia.

    Manh, Vivian M; Holmes, Jonathan M; Lazar, Elizabeth L; Kraker, Raymond T; Wallace, David K; Kulp, Marjean T; Galvin, Jennifer A; Shah, Birva K; Davis, Patricia L

    2018-02-01

    To compare visual acuity (VA) improvement in teenagers with amblyopia treated with a binocular iPad game vs part-time patching. One hundred participants aged 13 to 75% of prescribed treatment. In teenagers aged 13 to <17 years, improvement in amblyopic eye VA with the binocular iPad game used in this study was not found to be better than patching, and was possibly worse. Nevertheless, it remains unclear whether the minimal treatment response to binocular treatment was owing to poor treatment adherence or lack of treatment effect. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Indirect detection of dark matter

    Pieri, L.

    2008-01-01

    In the Cold Dark Matter scenario, the Dark Matter particle candidate may be a Weakly Interacting Massive Particle (Wimp). Annihilation of two Wimps in local or cosmological structures would result in the production of a number of standard model particles such as photons, leptons and baryons which could be observed with the presently available or future experiments such as the Pamela or Glast satellites or the Cherenkov Telescopes. In this work we review the status-of-the-art of the theoretical and phenomenological studies about the possibility of indirect detection of signals coming from Wimp annihilation.

  16. Indirect detection of dark matter

    Carr, J; Lamanna, G; Lavalle, J

    2006-01-01

    This article is an experimental review of the status and prospects of indirect searches for dark matter. Experiments observe secondary particles such as positrons, antiprotons, antideuterons, gamma-rays and neutrinos which could originate from annihilations of dark matter particles in various locations in the galaxy. Data exist from some experiments which have been interpreted as hints of evidence for dark matter. These data and their interpretations are reviewed together with the new experiments which are planned to resolve the puzzles and make new measurements which could give unambiguous results

  17. Indirect Medical Education and Disproportionate Share Adj...

    U.S. Department of Health & Human Services — Indirect Medical Education and Disproportionate Share Adjustments to Medicare Inpatient Payment Rates The indirect medical education (IME) and disproportionate share...

  18. Binocular vision in a virtual world: visual deficits following the wearing of a head-mounted display.

    Mon-Williams, M; Wann, J P; Rushton, S

    1993-10-01

    The short-term effects on binocular stability of wearing a conventional head-mounted display (HMD) to explore a virtual reality environment were examined. Twenty adult subjects (aged 19-29 years) wore a commercially available HMD for 10 min while cycling around a computer generated 3-D world. The twin screen presentations were set to suit the average interpupillary distance of our subject population, to mimic the conditions of public access virtual reality systems. Subjects were examined before and after exposure to the HMD and there were clear signs of induced binocular stress for a number of the subjects. The implications of introducing such HMDs into the workplace and entertainment environments are discussed.

  19. Indirect costs of rheumatoid arthritis

    Filip Raciborski

    2015-12-01

    Full Text Available It is estimated that in Poland about 400,000 persons in general suffer from inflammatory joint diseases, including rheumatoid arthritis (RA. Epidemiological surveys documenting the frequency and disturbance of musculoskeletal disorders in the Polish population are few in number. Most of the estimations are based on epidemiological data from other countries (prevalence of 0.5–1%. According to the data of the National Health Fund in Poland 135,000–157,000 persons in total are treated because of rheumatoid arthritis per year [ICD10 (International Statistical Classification of Diseases and Related Health Problems: M05, M06]. In the case of this group of diseases indirect costs significantly outweigh the direct costs. Indirect costs increase together with activity level of the disease. The cost analysis of productivity loss of RA patients indicates that sickness absenteeism and informal care are the most burdensome. At the national level it amounts in total from 1.2 billion to 2.8 billion PLN per year, depending on the method of analysis. These costs could be significantly reduced through early diagnosis and introduction of effective treatment.

  20. Do infants detect indirect reciprocity?

    Meristo, Marek; Surian, Luca

    2013-10-01

    In social interactions involving indirect reciprocity, agent A acts prosocially towards B and this prompts C to act prosocially towards A. This happens because A's actions enhanced its reputation in the eyes of third parties. Indirect reciprocity may have been of central importance in the evolution of morality as one of the major mechanisms leading to the selection of helping and fair attitudes. Here we show that 10-month-old infants expect third parties to act positively towards fair donors who have distributed attractive resources equally between two recipients, rather than toward unfair donors who made unequal distributions. Infants' responses were dependent on the reciprocator's perceptual exposure to previous relevant events: they expected the reciprocator to reward the fair donor only when it had seen the distributive actions performed by the donors. We propose that infants were able to generate evaluations of agents that were based on the fairness of their distributive actions and to generate expectations about the social preferences of informed third parties. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Indirect reciprocity with trinary reputations.

    Tanabe, Shoma; Suzuki, Hideyuki; Masuda, Naoki

    2013-01-21

    Indirect reciprocity is a reputation-based mechanism for cooperation in social dilemma situations when individuals do not repeatedly meet. The conditions under which cooperation based on indirect reciprocity occurs have been examined in great details. Most previous theoretical analysis assumed for mathematical tractability that an individual possesses a binary reputation value, i.e., good or bad, which depends on their past actions and other factors. However, in real situations, reputations of individuals may be multiple valued. Another puzzling discrepancy between the theory and experiments is the status of the so-called image scoring, in which cooperation and defection are judged to be good and bad, respectively, independent of other factors. Such an assessment rule is found in behavioral experiments, whereas it is known to be unstable in theory. In the present study, we fill both gaps by analyzing a trinary reputation model. By an exhaustive search, we identify all the cooperative and stable equilibria composed of a homogeneous population or a heterogeneous population containing two types of players. Some results derived for the trinary reputation model are direct extensions of those for the binary model. However, we find that the trinary model allows cooperation under image scoring under some mild conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Indirect Cost Reimbursement: An Industrial View.

    Bolton, Robert

    1987-01-01

    The meaning of indirect costs in an industrial environment is discussed. Other factors considered are corporate policies; nature of work being supported; the uniqueness of the work; who is doing the negotiating for industry; and indirect rates. Suggestions are offered for approaches to indirect cost reimbursement. (Author/MLW)

  3. Language shifts in free indirect discourse

    Maier, Emar

    Free indirect discourse is a way of reporting what a protagonist thinks or says that is distinct from both direct and indirect discourse. In particular, while pronouns and tenses are presented from the narrator's perspective, as in indirect discourse, other indexical and expressive elements reflect

  4. Directe en indirecte werknemersparticipatie in Europa

    van Houten, Gijs; Akkerman, Agnes; Sluiter, Roderick; Jansen, Giedo; Vermeylen, Greet

    2016-01-01

    This study looks at different forms of direct and indirect employee participation in the EU. The research questions are: (1) which forms of direct and indirect employee participation can we distinguish?; (2) to what extent do forms of direct and indirect employee participation coincide within

  5. Evaluation of binocular function among pre- and early-presbyopes with asthenopia

    Reindel W

    2018-01-01

    Full Text Available William Reindel,1 Lening Zhang,1 Joseph Chinn,2 Marjorie Rah1 1Vision Care, Bausch & Lomb Inc, Rochester, NY, 2J Chinn LLC, Lafayette, CO, USA Purpose: Individuals approaching presbyopia may exhibit ocular symptoms as they contend with visual demands of near work, coupled with natural age-related changes in accommodation. Therefore, accommodation and vergence of 30- to 40-year-old, myopic, soft contact lens wearing subjects with symptoms of asthenopia and no history of using multifocal lenses were evaluated.Patients and methods: In this prospective, observational study, 253 subjects with asthenopia were evaluated by 25 qualified practitioners, each at a different clinical site. Subjects were 30–40 years in age, had symptoms of soreness, eyestrain, tired eyes, or headaches with near work, regularly performed 2–3 consecutive hours of near work, and were undiagnosed with presbyopia. Amplitude of accommodation (AC and near point convergence (NPC were measured with a Royal Air Force binocular gauge. Triplicate push up and push down AC and NPC measures were recorded, and average AC values were compared to those calculated using the Hofstetter formula (HF. Results: The average AC push up/push down value was significantly better than the HF prediction for this age range (8.04±3.09 vs 6.23±0.80 D, although 22.5% of subjects had mean AC below their HF value (5.36±0.99 D. The average NPC push up/push down value was 12.0±4.69 cm. The mean binocular AC value using the push up measure was significantly better than the push down measure (8.5±3.4 vs 7.6±3.0 D. The mean NPC value using the push up measure was significantly worse than the push down measure (13.0±5.0 vs 11.0±4.7 cm. The most frequent primary diagnosis was ill-sustained accommodation (54%, followed by accommodative insufficiency (18%, and accommodative infacility (12%. Conclusion: Based upon a standardized assessment of accommodation and vergence, ill-sustained accommodation was the

  6. Binocular stereo-navigation for three-dimensional thoracoscopic lung resection.

    Kanzaki, Masato; Isaka, Tamami; Kikkawa, Takuma; Sakamoto, Kei; Yoshiya, Takehito; Mitsuboshi, Shota; Oyama, Kunihiro; Murasugi, Masahide; Onuki, Takamasa

    2015-05-08

    This study investigated the efficacy of binocular stereo-navigation during three-dimensional (3-D) thoracoscopic sublobar resection (TSLR). From July 2001, the authors' department began to use a virtual 3-D pulmonary model on a personal computer (PC) for preoperative simulation before thoracoscopic lung resection and for intraoperative navigation during operation. From 120 of 1-mm thin-sliced high-resolution computed tomography (HRCT)-scan images of tumor and hilum, homemade software CTTRY allowed sugeons to mark pulmonary arteries, veins, bronchi, and tumor on the HRCT images manually. The location and thickness of pulmonary vessels and bronchi were rendered as diverse size cylinders. With the resulting numerical data, a 3-D image was reconstructed by Metasequoia shareware. Subsequently, the data of reconstructed 3-D images were converted to Autodesk data, which appeared on a stereoscopic-vision display. Surgeons wearing 3-D polarized glasses performed 3-D TSLR. The patients consisted of 5 men and 5 women, ranging in age from 65 to 84 years. The clinical diagnoses were a primary lung cancer in 6 cases and a solitary metastatic lung tumor in 4 cases. Eight single segmentectomies, one bi-segmentectomy, and one bi-subsegmentectomy were performed. Hilar lymphadenectomy with mediastinal lymph node sampling has been performed in 6 primary lung cancers, but four patients with metastatic lung tumors were performed without lymphadenectomy. The operation time and estimated blood loss ranged from 125 to 333 min and from 5 to 187 g, respectively. There were no intraoperative complications and no conversion to open thoracotomy and lobectomy. Postoperative courses of eight patients were uneventful, and another two patients had a prolonged lung air leak. The drainage duration and hospital stay ranged from 2 to 13 days and from 8 to 19 days, respectively. The tumor histology of primary lung cancer showed 5 adenocarcinoma and 1 squamous cell carcinoma. All primary lung

  7. Is there any evidence for the validity of diagnostic criteria used for accommodative and nonstrabismic binocular dysfunctions?

    Cacho-Martínez, Pilar; García-Muñoz, Ángel; Ruiz-Cantero, María Teresa

    2014-01-01

    To analyze the diagnostic criteria used in the scientific literature published in the past 25 years for accommodative and nonstrabismic binocular dysfunctions and to explore if the epidemiological analysis of diagnostic validity has been used to propose which clinical criteria should be used for diagnostic purposes. We carried out a systematic review of papers on accommodative and non-strabic binocular disorders published from 1986 to 2012 analysing the MEDLINE, CINAHL, PsycINFO and FRANCIS databases. We admitted original articles about diagnosis of these anomalies in any population. We identified 839 articles and 12 studies were included. The quality of included articles was assessed using the QUADAS-2 tool. The review shows a wide range of clinical signs and cut-off points between authors. Only 3 studies (regarding accommodative anomalies) assessed diagnostic accuracy of clinical signs. Their results suggest using the accommodative amplitude and monocular accommodative facility for diagnosing accommodative insufficiency and a high positive relative accommodation for accommodative excess. The remaining 9 articles did not analyze diagnostic accuracy, assessing a diagnosis with the criteria the authors considered. We also found differences between studies in the way of considering patients' symptomatology. 3 studies of 12 analyzed, performed a validation of a symptom survey used for convergence insufficiency. Scientific literature reveals differences between authors according to diagnostic criteria for accommodative and nonstrabismic binocular dysfunctions. Diagnostic accuracy studies show that there is only certain evidence for accommodative conditions. For binocular anomalies there is only evidence about a validated questionnaire for convergence insufficiency with no data of diagnostic accuracy. Copyright © 2012 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  8. Generalization of Figure-Ground Segmentation from Binocular to Monocular Vision in an Embodied Biological Brain Model

    2011-08-01

    figure and ground the luminance cue breaks down and gestalt contours can fail to pop out. In this case we rely on color, which, having weak stereopsis...REPORT Generalization of Figure - Ground Segmentation from Monocular to Binocular Vision in an Embodied Biological Brain Model 14. ABSTRACT 16. SECURITY...U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS figure - ground , neural network, object

  9. Visual cortex and auditory cortex activation in early binocularly blind macaques: A BOLD-fMRI study using auditory stimuli.

    Wang, Rong; Wu, Lingjie; Tang, Zuohua; Sun, Xinghuai; Feng, Xiaoyuan; Tang, Weijun; Qian, Wen; Wang, Jie; Jin, Lixin; Zhong, Yufeng; Xiao, Zebin

    2017-04-15

    Cross-modal plasticity within the visual and auditory cortices of early binocularly blind macaques is not well studied. In this study, four healthy neonatal macaques were assigned to group A (control group) or group B (binocularly blind group). Sixteen months later, blood oxygenation level-dependent functional imaging (BOLD-fMRI) was conducted to examine the activation in the visual and auditory cortices of each macaque while being tested using pure tones as auditory stimuli. The changes in the BOLD response in the visual and auditory cortices of all macaques were compared with immunofluorescence staining findings. Compared with group A, greater BOLD activity was observed in the bilateral visual cortices of group B, and this effect was particularly obvious in the right visual cortex. In addition, more activated volumes were found in the bilateral auditory cortices of group B than of group A, especially in the right auditory cortex. These findings were consistent with the fact that there were more c-Fos-positive cells in the bilateral visual and auditory cortices of group B compared with group A (p visual cortices of binocularly blind macaques can be reorganized to process auditory stimuli after visual deprivation, and this effect is more obvious in the right than the left visual cortex. These results indicate the establishment of cross-modal plasticity within the visual and auditory cortices. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Binocular Symmetry/Asymmetry of Scleral Redness as a Cue for Sadness, Healthiness, and Attractiveness in Humans

    Robert R. Provine

    2013-10-01

    Full Text Available Among primates, only humans have the white sclerae that provide the ground necessary to display their own color and that of the overlying conjunctiva. Scleral color, primarily redness, provides cues of socially and biologically significant information about an individual. The present study examines the effect of the asymmetry of binocular scleral redness on perceived sadness, healthiness, and attractiveness by contrasting ratings of images of individuals who had one, both, or neither sclera reddened by digital editing. Building upon previous research, this study further defines the details of the scleral color display and contributes to the more general issue of facial and body symmetry, predictors of phenotypic condition and genotypic quality that are of interest to evolutionary theorists. Individuals with binocular and monocular redness were rated as sadder, less healthy, and less attractive than those with untinted control sclerae, with ratings corresponding to the degree of redness or whiteness. Bilaterally symmetrical (binocular scleral redness or whiteness provided anchorage points for ratings, with ratings for bilaterally asymmetrical (monocular redness or whiteness falling between them; there was no unique effect of asymmetry.

  11. Nulling Data Reduction and On-Sky Performance of the Large Binocular Telescope Interferometer

    Defrere, D.; Hinz, P. M.; Mennesson, B.; Hoffman, W. F.; Millan-Gabet, R.; Skemer, A. J.; Bailey, V.; Danchi, W. C.; Downy, E. C.; Durney, O.; hide

    2016-01-01

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5-13 micrometers). In this paper, we focus on the mid-infrared (8-13 micrometers) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star Beta Leo. This is equivalent to an exozodiacal disk density of 15-30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  12. The effects of noise on binocular rivalry waves: a stochastic neural field model

    Webber, Matthew A; Bressloff, Paul C

    2013-01-01

    We analyze the effects of extrinsic noise on traveling waves of visual perception in a competitive neural field model of binocular rivalry. The model consists of two one-dimensional excitatory neural fields, whose activity variables represent the responses to left-eye and right-eye stimuli, respectively. The two networks mutually inhibit each other, and slow adaptation is incorporated into the model by taking the network connections to exhibit synaptic depression. We first show how, in the absence of any noise, the system supports a propagating composite wave consisting of an invading activity front in one network co-moving with a retreating front in the other network. Using a separation of time scales and perturbation methods previously developed for stochastic reaction–diffusion equations, we then show how extrinsic noise in the activity variables leads to a diffusive-like displacement (wandering) of the composite wave from its uniformly translating position at long time scales, and fluctuations in the wave profile around its instantaneous position at short time scales. We use our analysis to calculate the first-passage-time distribution for a stochastic rivalry wave to travel a fixed distance, which we find to be given by an inverse Gaussian. Finally, we investigate the effects of noise in the depression variables, which under an adiabatic approximation lead to quenched disorder in the neural fields during propagation of a wave. (paper)

  13. Effective Data-Driven Calibration for a Galvanometric Laser Scanning System Using Binocular Stereo Vision.

    Tu, Junchao; Zhang, Liyan

    2018-01-12

    A new solution to the problem of galvanometric laser scanning (GLS) system calibration is presented. Under the machine learning framework, we build a single-hidden layer feedforward neural network (SLFN)to represent the GLS system, which takes the digital control signal at the drives of the GLS system as input and the space vector of the corresponding outgoing laser beam as output. The training data set is obtained with the aid of a moving mechanism and a binocular stereo system. The parameters of the SLFN are efficiently solved in a closed form by using extreme learning machine (ELM). By quantitatively analyzing the regression precision with respective to the number of hidden neurons in the SLFN, we demonstrate that the proper number of hidden neurons can be safely chosen from a broad interval to guarantee good generalization performance. Compared to the traditional model-driven calibration, the proposed calibration method does not need a complex modeling process and is more accurate and stable. As the output of the network is the space vectors of the outgoing laser beams, it costs much less training time and can provide a uniform solution to both laser projection and 3D-reconstruction, in contrast with the existing data-driven calibration method which only works for the laser triangulation problem. Calibration experiment, projection experiment and 3D reconstruction experiment are respectively conducted to test the proposed method, and good results are obtained.

  14. Effective Data-Driven Calibration for a Galvanometric Laser Scanning System Using Binocular Stereo Vision

    Junchao Tu

    2018-01-01

    Full Text Available A new solution to the problem of galvanometric laser scanning (GLS system calibration is presented. Under the machine learning framework, we build a single-hidden layer feedforward neural network (SLFN)to represent the GLS system, which takes the digital control signal at the drives of the GLS system as input and the space vector of the corresponding outgoing laser beam as output. The training data set is obtained with the aid of a moving mechanism and a binocular stereo system. The parameters of the SLFN are efficiently solved in a closed form by using extreme learning machine (ELM. By quantitatively analyzing the regression precision with respective to the number of hidden neurons in the SLFN, we demonstrate that the proper number of hidden neurons can be safely chosen from a broad interval to guarantee good generalization performance. Compared to the traditional model-driven calibration, the proposed calibration method does not need a complex modeling process and is more accurate and stable. As the output of the network is the space vectors of the outgoing laser beams, it costs much less training time and can provide a uniform solution to both laser projection and 3D-reconstruction, in contrast with the existing data-driven calibration method which only works for the laser triangulation problem. Calibration experiment, projection experiment and 3D reconstruction experiment are respectively conducted to test the proposed method, and good results are obtained.

  15. An obstacle detection system using binocular stereo fisheye lenses for planetary rover navigation

    Liu, L.; Jia, J.; Li, L.

    In this paper we present an implementation of an obstacle detection system using binocular stereo fisheye lenses for planetary rover navigation The fisheye lenses can improve image acquisition efficiency and handle minimal clearance recovery problem because they provide a large field of view However the fisheye lens introduces significant distortion in the image and this will make it much more difficult to find a one-to-one correspondence In addition we have to improve the system accuracy and efficiency for robot navigation To compute dense depth maps accurately in real time the following five key issues are considered 1 using lookup tables for a tradeoff between time and space in fisheye distortion correction and correspondence matching 2 using an improved incremental calculation scheme for algorithmic optimization 3 multimedia instruction set MMX implementation 4 consistency check to remove wrong stereo matching problems suffering from occlusions or mismatches 5 constraints of the recovery space To realize obstacle detection robustly we use the following three steps 1 extracting the ground plane parameters using Randomized Hough Transform 2 filtering the ground and background 3 locating the obstacles by using connected region detection Experimental results show the system can run at 3 2fps in 2 0GHz PC with 640X480 pixels

  16. Calibration of Binocular Vision Sensors Based on Unknown-Sized Elliptical Stripe Images

    Zhen Liu

    2017-12-01

    Full Text Available Most of the existing calibration methods for binocular stereo vision sensor (BSVS depend on a high-accuracy target with feature points that are difficult and costly to manufacture and. In complex light conditions, optical filters are used for BSVS, but they affect imaging quality. Hence, the use of a high-accuracy target with certain-sized feature points for calibration is not feasible under such complex conditions. To solve these problems, a calibration method based on unknown-sized elliptical stripe images is proposed. With known intrinsic parameters, the proposed method adopts the elliptical stripes located on the parallel planes as a medium to calibrate BSVS online. In comparison with the common calibration methods, the proposed method avoids utilizing high-accuracy target with certain-sized feature points. Therefore, the proposed method is not only easy to implement but is a realistic method for the calibration of BSVS with optical filter. Changing the size of elliptical curves projected on the target solves the difficulty of applying the proposed method in different fields of view and distances. Simulative and physical experiments are conducted to validate the efficiency of the proposed method. When the field of view is approximately 400 mm × 300 mm, the proposed method can reach a calibration accuracy of 0.03 mm, which is comparable with that of Zhang’s method.

  17. Managment and construction of the Large Binocular Telescope enclosure: Meeting unusual challenges with a competitive discipline

    Slagle, James H.; Hill, John M.; Davison, Warren B.; Hart, Wood; Teran, Jose U.

    1998-08-01

    Planning, estimating, and building a telescope and its enclosure within a budget is a challenge to any project staff. The Large Binocular Telescope (LBT) project office goal has been to break every phase of the project into small packages and competitively bid the packages. In this way the project office can minimize costs and keep the project budget from escalating out of control. This paper will discuss both the unique and common problems associated with the building of telescopes into the next millennium. The discussion is centered on the planning and execution phases of construction for the LBT, located on Mt. Graham in Arizona. The paper will discuss the effects of delays on the actual start of the telescope due to environmental issues and the impact the delays had on design and budget. The paper will provide the solutions that have been incorporated by the LBT project office to maximize the quality of construction while holding costs to a minimum. The use of a team approach by the contractors, engineers, and the project office has been successful in maintaining quality construction at a reasonable cost.

  18. Effect of Visual Angle on the Head Movement Caused by Changing Binocular Disparity

    Toru Maekawa

    2011-10-01

    Full Text Available It has been shown that vertical binocular disparity has no or little effect on the perception of visual direction (Banks et al., 2002. On the other hand, our previous study has reported that a continuous change of vertical disparity causes an involuntary sway of the head (Maekawa et al., 2009. We predict that the difference between those results attributes to the dissociation between the processes for perception and action in the brain. The aim of this study is to investigate in more details the condition that influences the process of disparity information. The present experiment particularly varied the visual angle of stimulus presentation and measured the head movement and body sway caused by changing vertical disparity. Results showed that the head movement was greater as the visual angle of the stimulus was smaller. It has been reported that stimulus of only small visual angle affect depth perception (Erklens et al., 1995. Thus, our result suggests that perception and action produced by vertical disparity are consistent as far as the effect of the stimulus size is concerned.

  19. The reproducibility of binocular pattern reversal visual evoked potentials: a single subject design.

    Mellow, Tessa B; Liasis, Alki; Lyons, Ruth; Thompson, Dorothy A

    2011-06-01

    This study aimed to investigate the within-participant variability over time of both amplitude and peak latency measures of pattern reversal visual evoked potentials (pVEPs). As a large number of factors are known to contribute to the variability of the pVEPs (such as fixation instability and drowsiness), testing was conducted in controlled conditions with two co-operative participants. PVEPs were recorded during 24 sessions, over an eight-week period using the same equipment and recording settings. The participants viewed a plasma monitor binocularly from a distance of 1 meter. High contrast (97%), black and white checks of side subtense 50', 25', and 12.5' pattern reversed 3/s in a 28 degree test field. The different sized checks were presented in a pseudo-random order. Three runs, each of 100 trials, were acquired to each stimulus from an active electrode placed at Oz referred to aFz. The amplitude of N80-P100 and the latency of P100 were measured. P100 amplitude and latency were stable across sessions and did not depend upon the order of check size presentation. As expected, variation in amplitude was greater than peak latency. The coefficients of variation for different check sizes and participants were 9-14% for pVEP amplitude, but only 1-2% for P100 latency.

  20. Differences of accommodative responses between two eyes under binocular viewing condition mediated by polarizing glasses

    Rui-Qing Wang

    2016-04-01

    Full Text Available AIM:To study the differences of accommodative responses between the two eyes under 3 different polarized viewing conditions. METHODS:Fifteen volunteers with emmetrope were recruited into this study(aged 18~38, 6 males and 9 females. Three different viewing conditions were set up by using polarizing glasses and liquid crystal display:(1right eye could see the visual target on the screen, but left eye cannot see it;(2left eye could see the visual target on the screen, but right eye cannot see it;(3both eyes could see the target. Accommodative responses were measured by infrared auto-refractor when fixating at the target at 5, 2, 1, 0.5 and 0.33m under the above 3 viewing conditions. The differences of accommodative responses under different viewing conditions were compared by using variance analysis of repeated measuring and t test. RESULTS:Significant differences of accommodative responses between the two eyes were found under condition(1and(2at all the fixating distance. The accommodative responses in used eyes which can see the visual target were higher than in non-used eyes which cannot see the visual target(PP>0.05. CONCLUSION:Ciliary muscles in the used eyes were more relatively tonic than non-used eyes under binocular open viewing condition. The imbalance of accommodative responses between two eyes may be one of the risk factors resulting into the occurrence of myopia.

  1. NULLING DATA REDUCTION AND ON-SKY PERFORMANCE OF THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    Defrère, D.; Hinz, P. M.; Hoffmann, W. F.; Skemer, A. J.; Bailey, V.; Downey, E. C.; Durney, O.; Grenz, P.; McMahon, T. J.; Montoya, M.; Spalding, E.; Vaz, A.; Arbo, P.; Brusa, G. [Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Mennesson, B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Millan-Gabet, R. [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Danchi, W. C. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States); Hill, J. M. [Large Binocular Telescope Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Absil, O. [Institut d’Astrophysique et de Géophysique, Université de Liège, 19c Allée du Six Août, B-4000 Sart Tilman (Belgium); Bailey, H., E-mail: ddefrere@email.arizona.edu [Lunar and Planetary Laboratory, University of Arizona, 1541 E, University Boulevard, Tucson, AZ 85721 (United States); and others

    2016-06-20

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5–13 μ m). In this paper, we focus on the mid-infrared (8–13 μ m) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star β Leo. This is equivalent to an exozodiacal disk density of 15–30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  2. Monocular zones in stereoscopic scenes: A useful source of information for human binocular vision?

    Harris, Julie M.

    2010-02-01

    When an object is closer to an observer than the background, the small differences between right and left eye views are interpreted by the human brain as depth. This basic ability of the human visual system, called stereopsis, lies at the core of all binocular three-dimensional (3-D) perception and related technological display development. To achieve stereopsis, it is traditionally assumed that corresponding locations in the right and left eye's views must first be matched, then the relative differences between right and left eye locations are used to calculate depth. But this is not the whole story. At every object-background boundary, there are regions of the background that only one eye can see because, in the other eye's view, the foreground object occludes that region of background. Such monocular zones do not have a corresponding match in the other eye's view and can thus cause problems for depth extraction algorithms. In this paper I will discuss evidence, from our knowledge of human visual perception, illustrating that monocular zones do not pose problems for our human visual systems, rather, our visual systems can extract depth from such zones. I review the relevant human perception literature in this area, and show some recent data aimed at quantifying the perception of depth from monocular zones. The paper finishes with a discussion of the potential importance of considering monocular zones, for stereo display technology and depth compression algorithms.

  3. The implementation of depth measurement and related algorithms based on binocular vision in embedded AM5728

    Deng, Zhiwei; Li, Xicai; Shi, Junsheng; Huang, Xiaoqiao; Li, Feiyan

    2018-01-01

    Depth measurement is the most basic measurement in various machine vision, such as automatic driving, unmanned aerial vehicle (UAV), robot and so on. And it has a wide range of use. With the development of image processing technology and the improvement of hardware miniaturization and processing speed, real-time depth measurement using dual cameras has become a reality. In this paper, an embedded AM5728 and the ordinary low-cost dual camera is used as the hardware platform. The related algorithms of dual camera calibration, image matching and depth calculation have been studied and implemented on the hardware platform, and hardware design and the rationality of the related algorithms of the system are tested. The experimental results show that the system can realize simultaneous acquisition of binocular images, switching of left and right video sources, display of depth image and depth range. For images with a resolution of 640 × 480, the processing speed of the system can be up to 25 fps. The experimental results show that the optimal measurement range of the system is from 0.5 to 1.5 meter, and the relative error of the distance measurement is less than 5%. Compared with the PC, ARM11 and DMCU hardware platforms, the embedded AM5728 hardware is good at meeting real-time depth measurement requirements in ensuring the image resolution.

  4. Precise positioning method for multi-process connecting based on binocular vision

    Liu, Wei; Ding, Lichao; Zhao, Kai; Li, Xiao; Wang, Ling; Jia, Zhenyuan

    2016-01-01

    With the rapid development of aviation and aerospace, the demand for metal coating parts such as antenna reflector, eddy-current sensor and signal transmitter, etc. is more and more urgent. Such parts with varied feature dimensions, complex three-dimensional structures, and high geometric accuracy are generally fabricated by the combination of different manufacturing technology. However, it is difficult to ensure the machining precision because of the connection error between different processing methods. Therefore, a precise positioning method is proposed based on binocular micro stereo vision in this paper. Firstly, a novel and efficient camera calibration method for stereoscopic microscope is presented to solve the problems of narrow view field, small depth of focus and too many nonlinear distortions. Secondly, the extraction algorithms for law curve and free curve are given, and the spatial position relationship between the micro vision system and the machining system is determined accurately. Thirdly, a precise positioning system based on micro stereovision is set up and then embedded in a CNC machining experiment platform. Finally, the verification experiment of the positioning accuracy is conducted and the experimental results indicated that the average errors of the proposed method in the X and Y directions are 2.250 μm and 1.777 μm, respectively.

  5. The effects of noise on binocular rivalry waves: a stochastic neural field model

    Webber, Matthew A

    2013-03-12

    We analyze the effects of extrinsic noise on traveling waves of visual perception in a competitive neural field model of binocular rivalry. The model consists of two one-dimensional excitatory neural fields, whose activity variables represent the responses to left-eye and right-eye stimuli, respectively. The two networks mutually inhibit each other, and slow adaptation is incorporated into the model by taking the network connections to exhibit synaptic depression. We first show how, in the absence of any noise, the system supports a propagating composite wave consisting of an invading activity front in one network co-moving with a retreating front in the other network. Using a separation of time scales and perturbation methods previously developed for stochastic reaction-diffusion equations, we then show how extrinsic noise in the activity variables leads to a diffusive-like displacement (wandering) of the composite wave from its uniformly translating position at long time scales, and fluctuations in the wave profile around its instantaneous position at short time scales. We use our analysis to calculate the first-passage-time distribution for a stochastic rivalry wave to travel a fixed distance, which we find to be given by an inverse Gaussian. Finally, we investigate the effects of noise in the depression variables, which under an adiabatic approximation lead to quenched disorder in the neural fields during propagation of a wave. © 2013 IOP Publishing Ltd and SISSA Medialab srl.

  6. Scanning laser ophthalmoscopy and optical coherence tomography imaging of spectacular ecdysis in the corn snake (Pantherophis guttatus) and the California king snake (Lampropeltis getulus californiae).

    Cazalot, Guillaume; Rival, Franck; Linsart, Adeline; Isard, Pierre-François; Tissier, Marion; Peiffer, Robert Louis; Dulaurent, Thomas

    2015-01-01

    One of the singularities of the eyes of snakes is the presence of the spectacle, a transparent and vascularized integument covering the cornea. The spectacle is completely renewed during ecdysis. Combined scanning laser ophthalmoscopy (SLO), optical coherence tomography (OCT), and conventional macrophotography were used to image this phenomenon. A spectral OCT/SLO examination and macrophotography were performed in four healthy adult corn snakes (Pantherophis guttatus) and one healthy adult California king snake (Lampropeltis getulus californiae) the day before the start of ecdysis and then daily during ecdysis. In all animals, ecdysis lasted 5 days. The spectacle was hardly visible at baseline, but became obvious at day one, while the subspectacular space became larger and the superficial cornea presented a hyperechoic band. At day two, eye surface became translucent, and at the same time, vascularization of the spectacle was visible using SLO. At day 3, the vascularization was no longer visible, while the subspectacular space increased and the eye surface remained translucent. At day 4, the eye surface was transparent and the superficial hyperechoic band started to become less bright. At day 5, the old spectacle was shed and all the parameters returned to baseline. We hypothesize that the echogenicity modifications of the anterior cornea correspond to major metabolic activity associated with new spectacle formation. This increased metabolic activity may contribute to the neovascularization and play an important role in the accumulation of fluid in the subspectacular space, facilitating the shedding of the old spectacle. © 2014 American College of Veterinary Ophthalmologists.

  7. Volumetric fluorescence retinal imaging in vivo over a 30-degree field of view by oblique scanning laser ophthalmoscopy (oSLO).

    Zhang, Lei; Song, Weiye; Shao, Di; Zhang, Sui; Desai, Manishi; Ness, Steven; Roy, Sayon; Yi, Ji

    2018-01-01

    While fluorescent contrast is widely used in ophthalmology, three-dimensional (3D) fluorescence retinal imaging over a large field of view (FOV) has been challenging. In this paper, we describe a novel oblique scanning laser ophthalmoscopy (oSLO) technique that provides 3D volumetric fluorescence retinal imaging with only one raster scan. The technique utilizes scanned oblique illumination and angled detection to obtain fluorescent cross-sectional images, analogous to optical coherence tomography (OCT) line scans (or B-scans). By breaking the coaxial optical alignment used in conventional retinal imaging modalities, depth resolution is drastically improved. To demonstrate the capability of oSLO, we have performed in vivo volumetric fluorescein angiography (FA) of the rat retina with ~25μm depth resolution and over a 30° FOV. Using depth segmentation, oSLO can obtain high contrast images of the microvasculature down to single capillaries in 3D. The multi-modal nature of oSLO also allows for seamless combination with simultaneous OCT angiography.

  8. Accuracy of deep learning, a machine-learning technology, using ultra-wide-field fundus ophthalmoscopy for detecting rhegmatogenous retinal detachment.

    Ohsugi, Hideharu; Tabuchi, Hitoshi; Enno, Hiroki; Ishitobi, Naofumi

    2017-08-25

    Rhegmatogenous retinal detachment (RRD) is a serious condition that can lead to blindness; however, it is highly treatable with timely and appropriate treatment. Thus, early diagnosis and treatment of RRD is crucial. In this study, we applied deep learning, a machine-learning technology, to detect RRD using ultra-wide-field fundus images and investigated its performance. In total, 411 images (329 for training and 82 for grading) from 407 RRD patients and 420 images (336 for training and 84 for grading) from 238 non-RRD patients were used in this study. The deep learning model demonstrated a high sensitivity of 97.6% [95% confidence interval (CI), 94.2-100%] and a high specificity of 96.5% (95% CI, 90.2-100%), and the area under the curve was 0.988 (95% CI, 0.981-0.995). This model can improve medical care in remote areas where eye clinics are not available by using ultra-wide-field fundus ophthalmoscopy for the accurate diagnosis of RRD. Early diagnosis of RRD can prevent blindness.

  9. Canine and feline fundus photography and videography using a nonpatented 3D printed lens adapter for a smartphone.

    Espinheira Gomes, Filipe; Ledbetter, Eric

    2018-05-11

    To describe an indirect funduscopy imaging technique for dogs and cats using low cost and widely available equipment: a smartphone, a three-dimensional (3D) printed indirect lens adapter, and a 40 diopters (D) indirect ophthalmoscopy lens. Fundus videography was performed in dogs and cats using a 40D indirect ophthalmoscopy lens and a smartphone fitted with a 3D printed indirect lens adapter. All animals were pharmacologically dilated with topical tropicamide 1% solution. Eyelid opening and video recording were performed using standard binocular indirect ophthalmoscopy technique. All videos were uploaded to a computer, and still images were selected and acquired for archiving purposes. Fundic images were manipulated to represent the true anatomy of the fundus. It was possible to promptly obtain good quality images from normal and diseased retinas using the nonpatented 3D printed, lens adapter for a smartphone. Fundic imaging using a smartphone can be performed with minimal investment. This simple imaging modality can be used by veterinary ophthalmologists and general practitioners to acquire, archive, and share images of the retina. The quality of images obtained will likely improve with developments in smartphone camera software and hardware. © 2018 American College of Veterinary Ophthalmologists.

  10. Computer-enhanced stereoscopic vision in a head-mounted operating binocular

    Birkfellner, Wolfgang; Figl, Michael; Matula, Christian; Hummel, Johann; Hanel, Rudolf; Imhof, Herwig; Wanschitz, Felix; Wagner, Arne; Watzinger, Franz; Bergmann, Helmar

    2003-01-01

    Based on the Varioscope, a commercially available head-mounted operating binocular, we have developed the Varioscope AR, a see through head-mounted display (HMD) for augmented reality visualization that seamlessly fits into the infrastructure of a surgical navigation system. We have assessed the extent to which stereoscopic visualization improves target localization in computer-aided surgery in a phantom study. In order to quantify the depth perception of a user aiming at a given target, we have designed a phantom simulating typical clinical situations in skull base surgery. Sixteen steel spheres were fixed at the base of a bony skull, and several typical craniotomies were applied. After having taken CT scans, the skull was filled with opaque jelly in order to simulate brain tissue. The positions of the spheres were registered using VISIT, a system for computer-aided surgical navigation. Then attempts were made to locate the steel spheres with a bayonet probe through the craniotomies using VISIT and the Varioscope AR as a stereoscopic display device. Localization of targets 4 mm in diameter using stereoscopic vision and additional visual cues indicating target proximity had a success rate (defined as a first-trial hit rate) of 87.5%. Using monoscopic vision and target proximity indication, the success rate was found to be 66.6%. Omission of visual hints on reaching a target yielded a success rate of 79.2% in the stereo case and 56.25% with monoscopic vision. Time requirements for localizing all 16 targets ranged from 7.5 min (stereo, with proximity cues) to 10 min (mono, without proximity cues). Navigation error is primarily governed by the accuracy of registration in the navigation system, whereas the HMD does not appear to influence localization significantly. We conclude that stereo vision is a valuable tool in augmented reality guided interventions. (note)

  11. New advances in amblyopia therapy I: binocular therapies and pharmacologic augmentation.

    Kraus, Courtney L; Culican, Susan M

    2018-05-18

    Amblyopia therapy options have traditionally been limited to penalisation of the non-amblyopic eye with either patching or pharmaceutical penalisation. Solid evidence, mostly from the Pediatric Eye Disease Investigator Group, has validated both number of hours a day of patching and days per week of atropine use. The use of glasses alone has also been established as a good first-line therapy for both anisometropic and strabismic amblyopia. Unfortunately, visual acuity equalisation or even improvement is not always attainable with these methods. Additionally, non-compliance with prescribed therapies contributes to treatment failures, with data supporting difficulty adhering to full treatment sessions. Interest in alternative therapies for amblyopia treatment has long been a topic of interest among researchers and clinicians alike. Incorporating new technology with an understanding of the biological basis of amblyopia has led to enthusiasm for binocular treatment of amblyopia. Early work on perceptual learning as well as more recent enthusiasm for iPad-based dichoptic training have each generated interesting and promising data for vision improvement in amblyopes. Use of pharmaceutical augmentation of traditional therapies has also been investigated. Several different drugs with unique mechanisms of action are thought to be able to neurosensitise the brain and enhance responsiveness to amblyopia therapy. No new treatment has emerged from currently available evidence as superior to the traditional therapies in common practice today. But ongoing investigation into the use of both new technology and the understanding of the neural basis of amblyopia promises alternate or perhaps better cures in the future. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  12. Design of a Binocular Pupil and Gaze Point Detection System Utilizing High Definition Images

    Yilmaz Durna

    2017-05-01

    Full Text Available This study proposes a novel binocular pupil and gaze detection system utilizing a remote full high definition (full HD camera and employing LabVIEW. LabVIEW is inherently parallel and has fewer time-consuming algorithms. Many eye tracker applications are monocular and use low resolution cameras due to real-time image processing difficulties. We utilized the computer’s direct access memory channel for rapid data transmission and processed full HD images with LabVIEW. Full HD images make easier determinations of center coordinates/sizes of pupil and corneal reflection. We modified the camera so that the camera sensor passed only infrared (IR images. Glints were taken as reference points for region of interest (ROI area selection of the eye region in the face image. A morphologic filter was applied for erosion of noise, and a weighted average technique was used for center detection. To test system accuracy with 11 participants, we produced a visual stimulus set up to analyze each eye’s movement. Nonlinear mapping function was utilized for gaze estimation. Pupil size, pupil position, glint position and gaze point coordinates were obtained with free natural head movements in our system. This system also works at 2046 × 1086 resolution at 40 frames per second. It is assumed that 280 frames per second for 640 × 480 pixel images is the case. Experimental results show that the average gaze detection error for 11 participants was 0.76° for the left eye, 0.89° for right eye and 0.83° for the mean of two eyes.

  13. Cortical microcircuit dynamics mediating Binocular Rivalry: The role of adaptation in inhibition

    Panagiota eTheodoni

    2011-11-01

    Full Text Available Perceptual bistability arises when two conflicting interpretations of an ambiguous stimulus or images in binocular rivalry (BR compete for perceptual dominance. From a computational point of view competition models based on cross-inhibition and adaptation have shown that noise is a crucial force for rivalry and operates in balance with adaptation in order to explain the observed alternations in perception. In particular, noise-driven transitions and adaptation-driven oscillations define two dynamical regimes and the system operates near its boundary. In order to gain insights into the microcircuit dynamics mediating spontaneous perceptual alternations we used a reduced recurrent attractor-based biophysically realistic spiking network well known for working memory, attention and decision-making, where a spike-frequency adaptation mechanism is implemented to account for perceptual bistability. We, thus, derived a consistently reduced four-variable population rate model using mean-field techniques and tested it on BR data collected from human subjects. Our model accounts for experimental data parameters such as time dominance, coefficient of variation and gamma distribution. In addition, we show that our model also operates on the boundary between noise and adaptation and agrees with Levelt’s second revised and fourth propositions. These results show for the first time that a consistent reduction of a biophysically realistic spiking network of integrate and fire neurons with spike frequency adaptation could account for BR. Moreover, we demonstrate that BR can be explained only through the dynamics of the competing neuronal pools, without taking into account the adaptation of inhibitory interneurons..However, adaptation of interneurons affects the optimal parametric space of the system, by decreasing the overall adaptation necessary for the bifurcation to occur.

  14. Distribution of Binocular Vision Anomalies and Refractive Errors in Iranian Children With Learning Disabilities

    Yekta

    2015-11-01

    Full Text Available Background Visual problems in children contribute to learning disorders, which are one of the most influential factors in learning. Objectives The aim of the present study was to determine the prevalence of refractive and binocular vision errors in children with learning disorders. Patients and Methods In this cross-sectional study, 406 children with learning disorders with a mean age of 8.56 ± 2.4 years were evaluated. Examinations included the determination of refractive errors with an auto-refractometer and static retinoscopy, measurement of visual acuity with a Snellen chart, evaluation of ocular deviation, and measurement of stereopsis, amplitude of accommodation, and near point of convergence. Results Of the 406 participants, 319 (78.6% were emmetropic in the right eye, 14.5% had myopia, and 6.9% had hyperopia according to cycloplegic refraction. Astigmatism was detected in 75 (18.5% children. In our study, 89.9% of the children had no deviation, 1.0% had esophoria, and 6.4% had exophoria . In addition, 2.2% of the children had suppression. The near point of convergence ranged from 3 to 18 cm, with a mean of 10.12 ± 3.274 cm. Moreover, 98.5 and 98.0% of the participants achieved complete vision with the best correction in the right and left eye, respectively. The best corrected visual acuity in the right and left eye was achieved in 98.5 and 98.0% of the children, respectively. Conclusions The pattern of visual impairment in learning-impaired children is not much different from that in normal children; however, because these children may not be able to express themselves clearly, lack of correct diagnosis and appropriate treatment has resulted in a marked defect in recognizing visual disorders in these children. Therefore, gaining knowledge of the prevalence of refractive errors in children with learning disorders can be considered the first step in their treatment.

  15. Binocular vision and abnormal head posture in children when watching television

    Di Zhang

    2016-05-01

    Full Text Available AIM: To determine the association between the binocular vision and an abnormal head posture (AHP when watching television (TV in children 7-14y of age. METHODS: Fifty normal children in the normal group and 52 children with an AHP when watching TV in the AHP group were tested for spherical equivalents, far and near fusional convergence (FC and fusional divergence (FD amplitudes, near point of convergence, far and near heterophoria, accommodative convergence/ accommodation ratio and stereoacuity. The values of these tests were compared between the two groups. The independent t test was applied at a confidence level of 95%. RESULTS: The far and near FC amplitudes and far FD amplitudes were lower in the AHP group (the far FC amplitudes: break point 13.6±5.4△, recovery point 8.7±5.4△. The near FC amplitudes: break point 14.5±7.3△, recovery point 10.3±5.1△. The far FD amplitudes: break point 3.9±2.7△, recovery point 2.6±2.3△ compared with those in the normal group (the far FC amplitudes: break point 19.1±6.2△, recovery point 12.4±4.5△. The near FC amplitudes: break point 22.3±8.0△, recovery point 16.1±5.7△. The far FD amplitudes: break point 7.0±2.1△, recovery point 4.6±1.9△. Other tests presented no statistically significant differences. CONCLUSION: An association between the reduced FC and FD amplitudes and the AHP in children when watching TV is proposed in the study. This kind of AHP is considered to be an anomalous manifestation which appears in a part of puerile patients of fusional vergence dysfunction.

  16. Indirect Self-Destructiveness and Emotional Intelligence.

    Tsirigotis, Konstantinos

    2016-06-01

    While emotional intelligence may have a favourable influence on the life and psychological and social functioning of the individual, indirect self-destructiveness exerts a rather negative influence. The aim of this study has been to explore possible relations between indirect self-destructiveness and emotional intelligence. A population of 260 individuals (130 females and 130 males) aged 20-30 (mean age of 24.5) was studied by using the Polish version of the chronic self-destructiveness scale and INTE, i.e., the Polish version of the assessing emotions scale. Indirect self-destructiveness has significant correlations with all variables of INTE (overall score, factor I, factor II), and these correlations are negative. The intensity of indirect self-destructiveness differentiates significantly the height of the emotional intelligence and vice versa: the height of the emotional intelligence differentiates significantly the intensity of indirect self-destructiveness. Indirect self-destructiveness has negative correlations with emotional intelligence as well as its components: the ability to recognize emotions and the ability to utilize emotions. The height of emotional intelligence differentiates the intensity of indirect self-destructiveness, and vice versa: the intensity of indirect self-destructiveness differentiates the height of emotional intelligence. It seems advisable to use emotional intelligence in the prophylactic and therapeutic work with persons with various types of disorders, especially with the syndrome of indirect self-destructiveness.

  17. Effect of a Binocular iPad Game vs Part-time Patching in Children Aged 5 to 12 Years With Amblyopia: A Randomized Clinical Trial.

    Holmes, Jonathan M; Manh, Vivian M; Lazar, Elizabeth L; Beck, Roy W; Birch, Eileen E; Kraker, Raymond T; Crouch, Eric R; Erzurum, S Ayse; Khuddus, Nausheen; Summers, Allison I; Wallace, David K

    2016-12-01

    A binocular approach to treating anisometropic and strabismic amblyopia has recently been advocated. Initial studies have yielded promising results, suggesting that a larger randomized clinical trial is warranted. To compare visual acuity (VA) improvement in children with amblyopia treated with a binocular iPad game vs part-time patching. A multicenter, noninferiority randomized clinical trial was conducted in community and institutional practices from September 16, 2014, to August 28, 2015. Participants included 385 children aged 5 years to younger than 13 years with amblyopia (20/40 to 20/200, mean 20/63) resulting from strabismus, anisometropia, or both. Participants were randomly assigned to either 16 weeks of a binocular iPad game prescribed for 1 hour a day (190 participants; binocular group) or patching of the fellow eye prescribed for 2 hours a day (195 participants; patching group). Study follow-up visits were scheduled at 4, 8, 12, and 16 weeks. A modified intent-to-treat analysis was performed on participants who completed the 16-week trial. Binocular iPad game or patching of the fellow eye. Change in amblyopic-eye VA from baseline to 16 weeks. Of the 385 participants, 187 were female (48.6%); mean (SD) age was 8.5 (1.9) years. At 16 weeks, mean amblyopic-eye VA improved 1.05 lines (2-sided 95% CI, 0.85-1.24 lines) in the binocular group and 1.35 lines (2-sided 95% CI, 1.17-1.54 lines) in the patching group, with an adjusted treatment group difference of 0.31 lines favoring patching (upper limit of the 1-sided 95% CI, 0.53 lines). This upper limit exceeded the prespecified noninferiority limit of 0.5 lines. Only 39 of the 176 participants (22.2%) randomized to the binocular game and with log file data available performed more than 75% of the prescribed treatment (median, 46%; interquartile range, 20%-72%). In younger participants (aged 5 to effects (including diplopia) were uncommon and of similar frequency between groups. In children aged 5 to younger

  18. Near Point of Convergence Break for Different Age Groups in Turkish Population with Normal Binocular Vision: Normative Data

    Nihat Sayın

    2013-12-01

    Full Text Available Purpose: The purpose of this study was to evaluate the near point of convergence break in Turkish population with normal binocular vision and to obtain the normative data for the near point of convergence break in different age groups. Such database has not been previously reported. Material and Method: In this prospective study, 329 subjects with normal binocular vision (age range, 3-72 years were evaluated. The near point of convergence break was measured 4 times repeatedly with an accommodative target. Mean values of near point of convergence break were provided for these age groups (≤10, 11-20, 21-30, 31-40, 41-50, 51-60, and >60 years old. A statistical comparison (one-way ANOVA and post-hoc test of these values between age groups was performed. A correlation between the near point of convergence break and age was evaluated by Pearson’s correlation test. Results: The mean value for near point of convergence break was 2.46±1.88 (0.5-14 cm. Specifically, 95% of measurements in all subjects were 60 year-old age groups in the near point of convergence break values (p=0.0001, p=0.0001, p=0.006, p=0.001, p= 0.004. A mild positive correlation was observed between the increase in near point of convergence break and increase of age (r=0.355 (p<0.001. Discussion: The values derived from a relatively large study population to establish a normative database for the near point of convergence break in the Turkish population with normal binocular vision are in relevance with age. This database has not been previously reported. (Turk J Ophthalmol 2013; 43: 402-6

  19. Metabolic changes in the visual cortex of binocular blindness macaque monkeys: a proton magnetic resonance spectroscopy study.

    Lingjie Wu

    Full Text Available PURPOSE: To evaluate proton magnetic resonance spectroscopy ((1H-MRS in a study of cross-modal plasticity in the visual cortex of binocular blindness macaque monkeys. MATERIALS AND METHODS: Four healthy neonatal macaque monkeys were randomly divided into 2 groups, with 2 in each group. Optic nerve transection was performed in both monkeys in the experimental group (group B to obtain binocular blindness. Two healthy macaque monkeys served as a control group (group A. After sixteen months post-procedure, (1H-MRS was performed in the visual cortex of all monkeys. We compared the peak areas of NAA, Cr, Cho, Glx and Ins and the ratios of NAA/Cr, Cho/Cr, Glx/Cr and Ins/Cr of each monkey in group B with group A. RESULTS: The peak area of NAA and the NAA/Cr ratio in the visual cortex of monkey 4 in group B were found to be dramatically decreased, the peak area of NAA slightly decreased and the NAA/Cr ratio clearly decreased in visual cortex of monkey 3 in group B than those in group A. The peak area of Ins and the Ins/Cr ratio in the visual cortex of monkey 4 in group B slightly increased. The peak area of Cho and the Cho/Cr ratio in the visual cortex of all monkeys in group B dramatically increased compared with group A. The peak area of Glx in the visual cortex of all monkeys in group B slightly increased compared with group A. CONCLUSIONS: (1H-MRS could detect biochemical and metabolic changes in the visual cortex and therefore this technique can be used to provide valuable information for investigating the mechanisms of cross-modal plasticity of binocular blindness in a macaque monkey model.

  20. Binocular Rivalry Measured 2 Hours After Occlusion Therapy Predicts the Recovery Rate of the Amblyopic Eye in Anisometropic Children.

    Lunghi, Claudia; Morrone, Maria Concetta; Secci, Jacopo; Caputo, Roberto

    2016-04-01

    Recent studies on adults have shown that short-term monocular deprivation boosts the deprived eye signal in binocular rivalry, reflecting homeostatic plasticity. Here we investigate whether homeostatic plasticity is present also during occlusion therapy for moderate amblyopia. Binocular rivalry and visual acuity (using Snellen charts for children) were measured in 10 children (mean age 6.2 ± 1 years) with moderate anisometropic amblyopia before the beginning of treatment and at four intervals during occlusion therapy (2 hours, 1, 2, and 5 months). Visual stimuli were orthogonal gratings presented dichoptically through ferromagnetic goggles and children reported verbally visual rivalrous perception. Bangerter filters were applied on the spectacle lens over the best eye for occlusion therapy. Two hours of occlusion therapy increased the nonamblyopic eye predominance over the amblyopic eye compared with pretreatment measurements, consistent with the results in adults. The boost of the nonamblyopic eye was still present after 1 month of treatment, steadily decreasing afterward to reach pretreatment levels after 2 months of continuous occlusion. Across subjects, the increase in nonamblyopic eye predominance observed after 2 hours of occlusion correlated (rho = -0.65, P = 0.04) with the visual acuity improvement of the amblyopic eye measured after 2 months of treatment. Homeostatic plasticity operates during occlusion therapy for moderate amblyopia and the increase in nonamblyopic eye dominance observed at the beginning of treatment correlates with the amblyopic eye recovery rate. These results suggest that binocular rivalry might be used to monitor visual cortical plasticity during occlusion therapy, although further investigations on larger clinical populations are needed to validate the predictive power of the technique.

  1. Influencia del estrés académico en el sistema binocular en universitarios de la UVA

    López Gómez, Alejandra

    2017-01-01

    Objetivo: El estrés visual, tras trabajo prolongado en cerca, produce modificaciones en el sistema binocular. Esta hipótesis ha sido poco contrastada experimentalmente. El objetivo principal es medir la influencia del estrés académico en estudiantes universitarios de la UVA mediante la medida de la foria. Métodos: Se ha medido la foria en 22 estudiantes, con su corrección habitual, antes y después de un examen, mediante tres métodos: técnica de la varilla de Maddox, técnica de Von Graefe y...

  2. Binocular fusion and invariant category learning due to predictive remapping during scanning of a depthful scene with eye movements

    Grossberg, Stephen; Srinivasan, Karthik; Yazdanbakhsh, Arash

    2015-01-01

    How does the brain maintain stable fusion of 3D scenes when the eyes move? Every eye movement causes each retinal position to process a different set of scenic features, and thus the brain needs to binocularly fuse new combinations of features at each position after an eye movement. Despite these breaks in retinotopic fusion due to each movement, previously fused representations of a scene in depth often appear stable. The 3D ARTSCAN neural model proposes how the brain does this by unifying ...

  3. Binocular disparity only comes into play when everything else fails; a finding with broader implications than one might suppose.

    Pizlo, Zygmunt; Li, Yunfeng; Steinman, Robert M

    2008-01-01

    This paper calls attention to research showing that binocular disparity, which is an effective cue to depth, plays a secondary role, at best, in the perception of 3D shape. This claim has implications both for how shape should be studied and how this unique perceptual property should be modeled. These issues are discussed from a historical perspective, which shows how the failure to appreciate the importance of the Gestalt grouping principle called 'Figure-Ground Organization' led to many unfruitful efforts. It also calls attention to how this situation can be remedied.

  4. Synchronization of indirectly coupled Lorenz oscillators

    Synchronization of indirectly coupled Lorenz oscillators: An experimental study. Amit Sharma Manish Dev Shrimali. Synchronization, Coupled Systems and Networks Volume 77 Issue 5 November 2011 pp 881-889 ... The in-phase and anti-phase synchronization of indirectly coupled chaotic oscillators reported in Phys. Rev ...

  5. Indirect search for dark matter with AMS

    Goy, Corinne

    2006-01-01

    This document summarises the potential of AMS in the indirect search for Dark Matter. Observations and cosmology indicate that the Universe may include a large amount of Dark Matter of unknown nature. A good candidate is the Ligthest Supersymmetric Particle in R-Parity conserving models. AMS offers a unique opportunity to study Dark Matter indirect signature in three spectra: gamma, antiprotons and positrons

  6. Indirectness in Discourse: Ethnicity as Conversational Style.

    Tannen, Deborah

    1981-01-01

    Examines social differences in expectations of indirectness in conversations between married couples, both Greek and Greek-American. Concludes that Greeks are more likely to expect indirectness in the context presented and that Greek-Americans have retained the Greek communicative patterns. (FL)

  7. JUSTIFICATION FOR INDIRECT DISCRIMINATION IN EU

    Cătălina-Adriana Ivănuş

    2014-11-01

    Full Text Available The right to non-discrimination is very important for a civilized society. EU legislation establishes direct and indirect discrimination, harassment, sexual harassment, instruction to discriminate and any less favourable treatment of a woman related to pregnancy or maternity leave as forms of discrimination. The law and the Court of Justice permit the justification of indirect discrimination.

  8. 77 FR 41899 - Indirect Food Additives: Polymers

    2012-07-17

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 177 [Docket No. FDA-2012-F-0031] Indirect Food Additives: Polymers AGENCY: Food and Drug Administration, HHS. ACTION... CFR part 177 is amended as follows: PART 177--INDIRECT FOOD ADDITIVES: POLYMERS 0 1. The authority...

  9. JUSTIFICATION FOR INDIRECT DISCRIMINATION IN EU

    Cătălina-Adriana Ivănuş

    2014-01-01

    The right to non-discrimination is very important for a civilized society. EU legislation establishes direct and indirect discrimination, harassment, sexual harassment, instruction to discriminate and any less favourable treatment of a woman related to pregnancy or maternity leave as forms of discrimination. The law and the Court of Justice permit the justification of indirect discrimination.

  10. Indirect techniques in nuclear astrophysics: a review.

    Tribble, R E; Bertulani, C A; Cognata, M La; Mukhamedzhanov, A M; Spitaleri, C

    2014-10-01

    In this review, we discuss the present status of three indirect techniques that are used to determine reaction rates for stellar burning processes, asymptotic normalization coefficients, the Trojan Horse method and Coulomb dissociation. A comprehensive review of the theory behind each of these techniques is presented. This is followed by an overview of the experiments that have been carried out using these indirect approaches.

  11. Multimodality optical coherence tomography and fluorescence confocal scanning laser ophthalmoscopy for image-guided feedback of intraocular injections in mouse models

    Benavides, Oscar R.; Terrones, Benjamin D.; Leeburg, Kelsey C.; Mehanathan, Sankarathi B.; Levine, Edward M.; Tao, Yuankai K.

    2018-02-01

    Rodent models are robust tools for understanding human retinal disease and function because of their similarities with human physiology and anatomy and availability of genetic mutants. Optical coherence tomography (OCT) has been well-established for ophthalmic imaging in rodents and enables depth-resolved visualization of structures and image-based surrogate biomarkers of disease. Similarly, fluorescence confocal scanning laser ophthalmoscopy (cSLO) has demonstrated utility for imaging endogenous and exogenous fluorescence and scattering contrast in the mouse retina. Complementary volumetric scattering and en face fluorescence contrast from OCT and cSLO, respectively, enables cellular-resolution longitudinal imaging of changes in ophthalmic structure and function. We present a non-contact multimodal OCT+cSLO small animal imaging system with extended working distance to the pupil, which enables imaging during and after intraocular injection. While injections are routinely performed in mice to develop novel models of ophthalmic diseases and screen novel therapeutics, the location and volume delivered is not precisely controlled and difficult to reproduce. Animals were imaged using a custom-built OCT engine and scan-head combined with a modified commercial cSLO scan-head. Post-injection imaging showed structural changes associated with retinal puncture, including the injection track, a retinal elevation, and detachment of the posterior hyaloid. When combined with imagesegmentation, we believe OCT can be used to precisely identify injection locations and quantify injection volumes. Fluorescence cSLO can provide complementary contrast for either fluorescently labeled compounds or transgenic cells for improved specificity. Our non-contact OCT+cSLO system is uniquely-suited for concurrent imaging with intraocular injections, which may be used for real-time image-guided injections.

  12. The Photosensitivity of Rhodopsin Bleaching and Light-Induced Increases of Fundus Reflectance in Mice Measured In Vivo With Scanning Laser Ophthalmoscopy

    Zhang, Pengfei; Goswami, Mayank; Zawadzki, Robert J.; Pugh, Edward N.

    2016-01-01

    Purpose To quantify bleaching-induced changes in fundus reflectance in the mouse retina. Methods Light reflected from the fundus of albino (Balb/c) and pigmented (C57Bl/6J) mice was measured with a multichannel scanning laser ophthalmoscopy optical coherence tomography (SLO-OCT) optical system. Serial scanning of small retinal regions was used for bleaching rhodopsin and measuring reflectance changes. Results Serial scanning generated a saturating reflectance increase centered at 501 nm with a photosensitivity of 1.4 × 10−8 per molecule μm2 in both strains, 2-fold higher than expected were irradiance at the rod outer segment base equal to that at the retinal surface. The action spectrum of the reflectance increase corresponds to the absorption spectrum of mouse rhodopsin in situ. Spectra obtained before and after bleaching were fitted with a model of fundus reflectance, quantifying contributions from loss of rhodopsin absorption with bleaching, absorption by oxygenated hemoglobin (HbO2) in the choroid (Balb/c), and absorption by melanin (C57Bl/6J). Both mouse strains exhibited light-induced broadband reflectance changes explained as bleaching-induced reflectivity increases at photoreceptor inner segment/outer segment (IS/OS) junctions and OS tips. Conclusions The elevated photosensitivity of rhodopsin bleaching in vivo is explained by waveguide condensing of light in propagation from rod inner segment (RIS) to rod outer segment (ROS). The similar photosensitivity of rhodopsin in the two strains reveals that little light backscattered from the sclera can enter the ROS. The bleaching-induced increases in reflectance at the IS/OS junctions and OS tips resemble results previously reported in human cones, but are ascribed to rods due to their 30/1 predominance over cones in mice and to the relatively minor amount of cone M-opsin in the regions scanned. PMID:27403994

  13. Indirect Calorimetry in Mechanically Ventilated Patients

    Allingstrup, Matilde Jo; Kondrup, Jens; Perner, Anders

    2017-01-01

    Background and Aims: The 2 currently available indirect calorimeters, CCM Express Indirect Calorimeter (MedGraphics, St Paul, MN) and Quark RMR ICU Indirect Calorimeter (COSMED, Rome, Italy), have not been validated against a gold standard in mechanically ventilated patients. Our aim was to do so...... using a gold-standard, modified Tissot bell-spirometer method in mechanically ventilated patients who were hemodynamically, respiratory, and metabolically stable. Methods: We studied 30 patients undergoing general anesthesia and major gynecological surgery. We measured oxygen consumption ((Formula...... of 77 (167) with limits of agreement −249 to 404 kcal/d. Conclusions: The QUARK RMR ICU Indirect Calorimeter compared better with the gold standard for values of (Formula presented.) O2 and REE than did the CCM Express Indirect Calorimeter in mechanically ventilated patients who were circulatory...

  14. PEPSI: The high-resolution échelle spectrograph and polarimeter for the Large Binocular Telescope

    Strassmeier, K. G.; Ilyin, I.; Järvinen, A.; Weber, M.; Woche, M.; Barnes, S. I.; Bauer, S.-M.; Beckert, E.; Bittner, W.; Bredthauer, R.; Carroll, T. A.; Denker, C.; Dionies, F.; DiVarano, I.; Döscher, D.; Fechner, T.; Feuerstein, D.; Granzer, T.; Hahn, T.; Harnisch, G.; Hofmann, A.; Lesser, M.; Paschke, J.; Pankratow, S.; Plank, V.; Plüschke, D.; Popow, E.; Sablowski, D.

    2015-05-01

    PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam Echelle Polarimetric and Spectroscopic Instrument for the 2×8.4 m Large Binocular Telescope (LBT). Three spectral resolutions of either 43 000, 120 000 or 270 000 can cover the entire optical/red wavelength range from 383 to 907 nm in three exposures. Two 10.3k×10.3k CCDs with 9-μm pixels and peak quantum efficiencies of 94-96 % record a total of 92 échelle orders. We introduce a new variant of a wave-guide image slicer with 3, 5, and 7 slices and peak efficiencies between 92-96 %. A total of six cross dispersers cover the six wavelength settings of the spectrograph, two of them always simultaneously. These are made of a VPH-grating sandwiched by two prisms. The peak efficiency of the system, including the telescope, is 15 % at 650 nm, and still 11 % and 10 % at 390 nm and 900 nm, respectively. In combination with the 110 m2 light-collecting capability of the LBT, we expect a limiting magnitude of ≈ 20th mag in V in the low-resolution mode. The R = 120 000 mode can also be used with two, dual-beam Stokes IQUV polarimeters. The 270 000-mode is made possible with the 7-slice image slicer and a 100-μm fibre through a projected sky aperture of 0.74 arcsec, comparable to the median seeing of the LBT site. The 43 000-mode with 12-pixel sampling per resolution element is our bad seeing or faint-object mode. Any of the three resolution modes can either be used with sky fibers for simultaneous sky exposures or with light from a stabilized Fabry-Pérot étalon for ultra-precise radial velocities. CCD-image processing is performed with the dedicated data-reduction and analysis package PEPSI-S4S. Its full error propagation through all image-processing steps allows an adaptive selection of parameters by using statistical inferences and robust estimators. A solar feed makes use of PEPSI during day time and a 500-m feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In this paper, we

  15. Expression of future prospective in indirect speech

    Bodnaruk Elena Vladimirovna

    2015-03-01

    Full Text Available The article analyzes the characteristics and use of grammatical semantics and lexical and grammatical means used to create future prospects in double indirect discourse. The material for the study were epic works by contemporary German writers. In the analysis of the empirical material it has been pointed out that indirect discourse has preterial basis and is the kind of most frequent inner speech of characters. The most widely used form with future semantics in preterial indirect speech is conditional I, formally having a conjunctive basis, but is mostly used with the indicative semantics. Competitive to conditional I in indirect speech is preterial indicative. A characteristic feature of the indirect speech is the use of modal verbs, which, thanks to its semantics is usually referred as an action at a later term, creating the prospect of future statements. The most frequent were modal verbs wollen and sollen in the form of the preterite, more rare verbs were m ssen and k nnen. German indirect speech distinguishes the ability to use forms on the basis of conjunctive: preterite and plusquamperfect of conjunctive. Both forms express values similar to those of the indicative. However, conjunctive forms the basis of the data shown in a slightly more pronounced seme of uncertainty that accompanies future uses of these forms in indirect speech. In addition, plusquamperfect conjunctive differs from others by the presence of the seme of completeness.

  16. Evaluation of a four month rehabilitation program for stroke patients with balance problems and binocular visual dysfunction.

    Schow, Trine; Harris, Paul; Teasdale, Thomas William; Rasmussen, Morten Arendt

    2016-04-06

    Balance problems and binocular visual dysfunction (BVD) are common problems after stroke, however evidence of an effective rehabilitation method are limited. To evaluate the effect of a four-month rehabilitation program for individuals with balance problems and BVD after a stroke. About 40 sessions of 1.5 hours duration over four months with visual therapy and balance rehabilitation, was provided to all 29 participants, aged 18-67 years, in groups of 7-8 individuals. Several measures for BVD, balance, gait, Health Related Quality Of Life (HRQoL) and functional recovery were used at baseline, at the end of training and at a six-month follow up (FU). We found significant improvements in stereopsis, vergence, saccadic movements, burden of binocular visual symptoms, balance and gait speed, fatigue, HRQoL and functional recovery. Moreover, 60% of the participants were in employment at the six-month FU, compared to only 23% before training. All improvements were sustained at the six-month FU. Although a control group is lacking, the evidence suggests that the positive improvement is a result of the combined visual and balance training. The combination of balance and visual training appears to facilitate changes at a multimodal level affecting several functions important in daily life.

  17. Indirect estimators in US federal programs

    1996-01-01

    In 1991, a subcommittee of the Federal Committee on Statistical Methodology met to document the use of indirect estimators - that is, estimators which use data drawn from a domain or time different from the domain or time for which an estimate is required. This volume comprises the eight reports which describe the use of indirect estimators and they are based on case studies from a variety of federal programs. As a result, many researchers will find this book provides a valuable survey of how indirect estimators are used in practice and which addresses some of the pitfalls of these methods.

  18. Bioelectrochemical Systems for Indirect Biohydrogen Production

    Regan, John M.; Yan, Hengjing

    2014-01-01

    by exoelectrogens at the anode. As an indirect approach to biohydrogen production, these systems are not subject to the hydrogen yield constraints of fermentative processes and have been proven to work with virtually any biodegradable organic substrate

  19. Indirect techniques in nuclear astrophysics: a review

    Tribble, R E; Mukhamedzhanov, A M; Bertulani, C A; Cognata, M La; Spitaleri, C

    2014-01-01

    In this review, we discuss the present status of three indirect techniques that are used to determine reaction rates for stellar burning processes, asymptotic normalization coefficients, the Trojan Horse method and Coulomb dissociation. A comprehensive review of the theory behind each of these techniques is presented. This is followed by an overview of the experiments that have been carried out using these indirect approaches. (review article)

  20. An Indirect Route for Ethanol Production

    Eggeman, T.; Verser, D.; Weber, E.

    2005-04-29

    The ZeaChem indirect method is a radically new approach to producing fuel ethanol from renewable resources. Sugar and syngas processing platforms are combined in a novel way that allows all fractions of biomass feedstocks (e.g. carbohydrates, lignins, etc.) to contribute their energy directly into the ethanol product via fermentation and hydrogen based chemical process technologies. The goals of this project were: (1) Collect engineering data necessary for scale-up of the indirect route for ethanol production, and (2) Produce process and economic models to guide the development effort. Both goals were successfully accomplished. The projected economics of the Base Case developed in this work are comparable to today's corn based ethanol technology. Sensitivity analysis shows that significant improvements in economics for the indirect route would result if a biomass feedstock rather that starch hydrolyzate were used as the carbohydrate source. The energy ratio, defined as the ratio of green energy produced divided by the amount of fossil energy consumed, is projected to be 3.11 to 12.32 for the indirect route depending upon the details of implementation. Conventional technology has an energy ratio of 1.34, thus the indirect route will have a significant environmental advantage over today's technology. Energy savings of 7.48 trillion Btu/yr will result when 100 MMgal/yr (neat) of ethanol capacity via the indirect route is placed on-line by the year 2010.

  1. Evaluation of baseline structural factors for predicting glaucomatous visual-field progression using optical coherence tomography, scanning laser polarimetry and confocal scanning laser ophthalmoscopy.

    Sehi, M; Bhardwaj, N; Chung, Y S; Greenfield, D S

    2012-12-01

    The objective of this study is to assess whether baseline optic nerve head (ONH) topography and retinal nerve fiber layer thickness (RNFLT) are predictive of glaucomatous visual-field progression in glaucoma suspect (GS) and glaucomatous eyes, and to calculate the level of risk associated with each of these parameters. Participants with ≥28 months of follow-up were recruited from the longitudinal Advanced Imaging for Glaucoma Study. All eyes underwent standard automated perimetry (SAP), confocal scanning laser ophthalmoscopy (CSLO), time-domain optical coherence tomography (TDOCT), and scanning laser polarimetry using enhanced corneal compensation (SLPECC) every 6 months. Visual-field progression was assessed using pointwise linear-regression analysis of SAP sensitivity values (progressor) and defined as significant sensitivity loss of >1 dB/year at ≥2 adjacent test locations in the same hemifield at P<0.01. Cox proportional hazard ratios (HR) were calculated to determine the predictive ability of baseline ONH and RNFL parameters for SAP progression using univariate and multivariate models. Seventy-three eyes of 73 patients (43 GS and 30 glaucoma, mean age 63.2±9.5 years) were enrolled (mean follow-up 51.5±11.3 months). Four of 43 GS (9.3%) and 6 of 30 (20%) glaucomatous eyes demonstrated progression. Mean time to progression was 50.8±11.4 months. Using multivariate models, abnormal CSLO temporal-inferior Moorfields classification (HR=3.76, 95% confidence interval (CI): 1.02-6.80, P=0.04), SLPECC inferior RNFLT (per -1 μm, HR=1.38, 95% CI: 1.02-2.2, P=0.02), and TDOCT inferior RNFLT (per -1 μm, HR=1.11, 95% CI: 1.04-1.2, P=0.001) had significant HRs for SAP progression. Abnormal baseline ONH topography and reduced inferior RNFL are predictive of SAP progression in GS and glaucomatous eyes.

  2. Incidence of vertical phoria on postural control during binocular vision: what perspective for prevention to nonspecific chronic pain management?

    Matheron, Eric; Kapoula, Zoï

    2015-01-01

    Vertical heterophoria (VH) is the latent vertical misalignment of the eyes when the retinal images are dissociated, vertical orthophoria (VO) when there is no misalignment. Studies on postural control, during binocular vision in upright stance, reported that healthy subjects with small VH vs. VO are less stable, but the experimental cancellation of VH with an appropriate prism improves postural stability. The same behavior was recorded in nonspecific chronic back pain subjects, all with VH. It was hypothesized that, without refraction problems, VH indicates a perturbation of the somaesthetic cues required in the sensorimotor loops involved in postural control and the capacity of the CNS to optimally integrate these cues, suggesting prevention possibilities. Sensorimotor conflict can induce pain and modify sensory perception in some healthy subjects; some nonspecific pain or chronic pain could result from such prolonged conflict in which VH could be a sign, with new theoretical and clinical implications.

  3. Landing performance by low-time private pilots after the sudden loss of binocular vision - Cyclops II

    Lewis, C. E., Jr.; Swaroop, R.; Mcmurty, T. C.; Blakeley, W. R.; Masters, R. L.

    1973-01-01

    Study of low-time general aviation pilots, who, in a series of spot landings, were suddenly deprived of binocular vision by patching either eye on the downwind leg of a standard, closed traffic pattern. Data collected during these landings were compared with control data from landings flown with normal vision during the same flight. The sequence of patching and the mix of control and monocular landings were randomized to minimize the effect of learning. No decrease in performance was observed during landings with vision restricted to one eye, in fact, performance improved. This observation is reported at a high level of confidence (p less than 0.001). These findings confirm the previous work of Lewis and Krier and have important implications with regard to aeromedical certification standards.

  4. The effect of first visual stimulation incorporation of labelled leucine into cerebral cortex of binocularly deprived kittens

    Mitros, K.; Kossut, M.; Skangiel-Kramska, J.; Mueller, L.; Niemierko, S.; Zernicki, B.

    1978-01-01

    One-month old kittens, binocularly deprived with hoods from birth, were used. Before the experiments in which visual stimulation was applied the brainstem of kittens was transected at the pretrigeminal level. Cortical EEG activity and ocular behavior indicated that the isolated cerebrum of preparations was usually awake during experiment. Patterned visual stimulation was directed to one hemisphere, while the other was used as a control. Visual stimulation evoked in some cases (in 8 out of 17) an increase of incorporation of labelled leucine into the proteins of the striate cortex. Electrophoresis on polyacrylamide gel did not reveal any differences in the pattern of insoluble proteins between the stimulated and control visual cortex. It is suggested that first visual stimulation may enhance the protein metabolism of striate cortex in young kittens. Some unknown up to now physiological factors (motivation, attention) may be critical for these phenomena. (author)

  5. Binocular versus standard occlusion or blurring treatment for unilateral amblyopia in children aged three to eight years.

    Tailor, Vijay; Bossi, Manuela; Bunce, Catey; Greenwood, John A; Dahlmann-Noor, Annegret

    2015-08-11

    Current treatments for amblyopia in children, occlusion and pharmacological blurring, have had limited success, with less than two-thirds of children achieving good visual acuity of at least 0.20 logMAR in the amblyopic eye, limited improvement of stereopsis, and poor compliance. A new treatment approach, based on the dichoptic presentation of movies or computer games (images presented separately to each eye), may yield better results, as it aims to balance the input of visual information from each eye to the brain. Compliance may also improve with these more child-friendly treatment procedures. To determine whether binocular treatments in children aged three to eight years with unilateral amblyopia result in better visual outcomes than conventional occlusion or pharmacological blurring treatment. We searched the Cochrane Eyes and Vision Group Trials Register (last date of searches: 14 April 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 3), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2015), EMBASE (January 1980 to April 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), 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. Two review authors independently screened the results of the search in order to identify studies that met the inclusion criteria of the review: randomised controlled trials (RCTs) that enrolled participants between the ages of three and eight years old with unilateral amblyopia, defined as best-corrected visual acuity (BCVA) worse than 0.200 logMAR in the amblyopic eye, and BCVA 0.200 logMAR or better in the fellow eye, in the presence of an amblyogenic risk factor such as anisometropia, strabismus, or both. Prior

  6. Analysis of indirect taxation in Ukraine

    Khodyakova Olga V.

    2014-01-01

    Full Text Available The goal of the article is analysis of the structure and dynamics of indirect taxes for the previous five years and also the influence of indirect taxation upon formation of income of the State Budget of Ukraine. The article analyses the modern state of indirect taxation in Ukraine. Specific weight of the value added tax, excise tax and customs duty are considered in the structure of tax receipts of the consolidated budget of Ukraine as indirect taxes. The article shows that receipts of the State Budget of Ukraine are mostly provided by indirect taxes. The Ukrainian taxation system is mostly a factor of reduction of the level of economic growth and investment activity in the country and the existing system of administering is not completely capable of excluding the possibility of tax evasion. The prospect of further studies in this direction is improvement of organisation of tax control in Ukraine and differentiation of the value added tax rates depending on the level of consumption of goods and level of income of consumers.

  7. Recognition and Matching of Clustered Mature Litchi Fruits Using Binocular Charge-Coupled Device (CCD Color Cameras

    Chenglin Wang

    2017-11-01

    Full Text Available Recognition and matching of litchi fruits are critical steps for litchi harvesting robots to successfully grasp litchi. However, due to the randomness of litchi growth, such as clustered growth with uncertain number of fruits and random occlusion by leaves, branches and other fruits, the recognition and matching of the fruit become a challenge. Therefore, this study firstly defined mature litchi fruit as three clustered categories. Then an approach for recognition and matching of clustered mature litchi fruit was developed based on litchi color images acquired by binocular charge-coupled device (CCD color cameras. The approach mainly included three steps: (1 calibration of binocular color cameras and litchi image acquisition; (2 segmentation of litchi fruits using four kinds of supervised classifiers, and recognition of the pre-defined categories of clustered litchi fruit using a pixel threshold method; and (3 matching the recognized clustered fruit using a geometric center-based matching method. The experimental results showed that the proposed recognition method could be robust against the influences of varying illumination and occlusion conditions, and precisely recognize clustered litchi fruit. In the tested 432 clustered litchi fruits, the highest and lowest average recognition rates were 94.17% and 92.00% under sunny back-lighting and partial occlusion, and sunny front-lighting and non-occlusion conditions, respectively. From 50 pairs of tested images, the highest and lowest matching success rates were 97.37% and 91.96% under sunny back-lighting and non-occlusion, and sunny front-lighting and partial occlusion conditions, respectively.

  8. Capturing age-related changes in functional contrast sensitivity with decreasing light levels in monocular and binocular vision.

    Gillespie-Gallery, Hanna; Konstantakopoulou, Evgenia; Harlow, Jonathan A; Barbur, John L

    2013-09-09

    It is challenging to separate the effects of normal aging of the retina and visual pathways independently from optical factors, decreased retinal illuminance, and early stage disease. This study determined limits to describe the effect of light level on normal, age-related changes in monocular and binocular functional contrast sensitivity. We recruited 95 participants aged 20 to 85 years. Contrast thresholds for correct orientation discrimination of the gap in a Landolt C optotype were measured using a 4-alternative, forced-choice (4AFC) procedure at screen luminances from 34 to 0.12 cd/m(2) at the fovea and parafovea (0° and ±4°). Pupil size was measured continuously. The Health of the Retina index (HRindex) was computed to capture the loss of contrast sensitivity with decreasing light level. Participants were excluded if they exhibited performance outside the normal limits of interocular differences or HRindex values, or signs of ocular disease. Parafoveal contrast thresholds showed a steeper decline and higher correlation with age at the parafovea than the fovea. Of participants with clinical signs of ocular disease, 83% had HRindex values outside the normal limits. Binocular summation of contrast signals declined with age, independent of interocular differences. The HRindex worsens more rapidly with age at the parafovea, consistent with histologic findings of rod loss and its link to age-related degenerative disease of the retina. The HRindex and interocular differences could be used to screen for and separate the earliest stages of subclinical disease from changes caused by normal aging.

  9. Binocular neurons in parastriate cortex: interocular 'matching' of receptive field properties, eye dominance and strength of silent suppression.

    Phillip A Romo

    Full Text Available Spike-responses of single binocular neurons were recorded from a distinct part of primary visual cortex, the parastriate cortex (cytoarchitectonic area 18 of anaesthetized and immobilized domestic cats. Functional identification of neurons was based on the ratios of phase-variant (F1 component to the mean firing rate (F0 of their spike-responses to optimized (orientation, direction, spatial and temporal frequencies and size sine-wave-luminance-modulated drifting grating patches presented separately via each eye. In over 95% of neurons, the interocular differences in the phase-sensitivities (differences in F1/F0 spike-response ratios were small (≤ 0.3 and in over 80% of neurons, the interocular differences in preferred orientations were ≤ 10°. The interocular correlations of the direction selectivity indices and optimal spatial frequencies, like those of the phase sensitivies and optimal orientations, were also strong (coefficients of correlation r ≥ 0.7005. By contrast, the interocular correlations of the optimal temporal frequencies, the diameters of summation areas of the excitatory responses and suppression indices were weak (coefficients of correlation r ≤ 0.4585. In cells with high eye dominance indices (HEDI cells, the mean magnitudes of suppressions evoked by stimulation of silent, extra-classical receptive fields via the non-dominant eyes, were significantly greater than those when the stimuli were presented via the dominant eyes. We argue that the well documented 'eye-origin specific' segregation of the lateral geniculate inputs underpinning distinct eye dominance columns in primary visual cortices of mammals with frontally positioned eyes (distinct eye dominance columns, combined with significant interocular differences in the strength of silent suppressive fields, putatively contribute to binocular stereoscopic vision.

  10. Image registration algorithm for high-voltage electric power live line working robot based on binocular vision

    Li, Chengqi; Ren, Zhigang; Yang, Bo; An, Qinghao; Yu, Xiangru; Li, Jinping

    2017-12-01

    In the process of dismounting and assembling the drop switch for the high-voltage electric power live line working (EPL2W) robot, one of the key problems is the precision of positioning for manipulators, gripper and the bolts used to fix drop switch. To solve it, we study the binocular vision system theory of the robot and the characteristic of dismounting and assembling drop switch. We propose a coarse-to-fine image registration algorithm based on image correlation, which can improve the positioning precision of manipulators and bolt significantly. The algorithm performs the following three steps: firstly, the target points are marked respectively in the right and left visions, and then the system judges whether the target point in right vision can satisfy the lowest registration accuracy by using the similarity of target points' backgrounds in right and left visions, this is a typical coarse-to-fine strategy; secondly, the system calculates the epipolar line, and then the regional sequence existing matching points is generated according to neighborhood of epipolar line, the optimal matching image is confirmed by calculating the similarity between template image in left vision and the region in regional sequence according to correlation matching; finally, the precise coordinates of target points in right and left visions are calculated according to the optimal matching image. The experiment results indicate that the positioning accuracy of image coordinate is within 2 pixels, the positioning accuracy in the world coordinate system is within 3 mm, the positioning accuracy of binocular vision satisfies the requirement dismounting and assembling the drop switch.

  11. Regulating the Access to Awareness: Brain Activity Related to Probe-related and Spontaneous Reversals in Binocular Rivalry.

    Metzger, Brian A; Mathewson, Kyle E; Tapia, Evelina; Fabiani, Monica; Gratton, Gabriele; Beck, Diane M

    2017-06-01

    Research on the neural correlates of consciousness (NCC) has implicated an assortment of brain regions, ERP components, and network properties associated with visual awareness. Recently, the P3b ERP component has emerged as a leading NCC candidate. However, typical P3b paradigms depend on the detection of some stimulus change, making it difficult to separate brain processes elicited by the stimulus itself from those associated with updates or changes in visual awareness. Here we used binocular rivalry to ask whether the P3b is associated with changes in awareness even in the absence of changes in the object of awareness. We recorded ERPs during a probe-mediated binocular rivalry paradigm in which brief probes were presented over the image in either the suppressed or dominant eye to determine whether the elicited P3b activity is probe or reversal related. We found that the timing of P3b (but not its amplitude) was closely related to the timing of the report of a perceptual change rather than to the onset of the probe. This is consistent with the proposal that P3b indexes updates in conscious awareness, rather than being related to stimulus processing per se. Conversely, the probe-related P1 amplitude (but not its latency) was associated with reversal latency, suggesting that the degree to which the probe is processed increases the likelihood of a fast perceptual reversal. Finally, the response-locked P3b amplitude (but not its latency) was associated with the duration of an intermediate stage between reversals in which parts of both percepts coexist (piecemeal period). Together, the data suggest that the P3b reflects an update in consciousness and that the intensity of that process (as indexed by P3b amplitude) predicts how immediate that update is.

  12. Vertical binocular disparity is encoded implicitly within a model neuronal population tuned to horizontal disparity and orientation.

    Jenny C A Read

    2010-04-01

    Full Text Available Primary visual cortex is often viewed as a "cyclopean retina", performing the initial encoding of binocular disparities between left and right images. Because the eyes are set apart horizontally in the head, binocular disparities are predominantly horizontal. Yet, especially in the visual periphery, a range of non-zero vertical disparities do occur and can influence perception. It has therefore been assumed that primary visual cortex must contain neurons tuned to a range of vertical disparities. Here, I show that this is not necessarily the case. Many disparity-selective neurons are most sensitive to changes in disparity orthogonal to their preferred orientation. That is, the disparity tuning surfaces, mapping their response to different two-dimensional (2D disparities, are elongated along the cell's preferred orientation. Because of this, even if a neuron's optimal 2D disparity has zero vertical component, the neuron will still respond best to a non-zero vertical disparity when probed with a sub-optimal horizontal disparity. This property can be used to decode 2D disparity, even allowing for realistic levels of neuronal noise. Even if all V1 neurons at a particular retinotopic location are tuned to the expected vertical disparity there (for example, zero at the fovea, the brain could still decode the magnitude and sign of departures from that expected value. This provides an intriguing counter-example to the common wisdom that, in order for a neuronal population to encode a quantity, its members must be tuned to a range of values of that quantity. It demonstrates that populations of disparity-selective neurons encode much richer information than previously appreciated. It suggests a possible strategy for the brain to extract rarely-occurring stimulus values, while concentrating neuronal resources on the most commonly-occurring situations.

  13. Binocular Fusion and Invariant Category Learning due to Predictive Remapping during Scanning of a Depthful Scene with Eye Movements

    Stephen eGrossberg

    2015-01-01

    Full Text Available How does the brain maintain stable fusion of 3D scenes when the eyes move? Every eye movement causes each retinal position to process a different set of scenic features, and thus the brain needs to binocularly fuse new combinations of features at each position after an eye movement. Despite these breaks in retinotopic fusion due to each movement, previously fused representations of a scene in depth often appear stable. The 3D ARTSCAN neural model proposes how the brain does this by unifying concepts about how multiple cortical areas in the What and Where cortical streams interact to coordinate processes of 3D boundary and surface perception, spatial attention, invariant object category learning, predictive remapping, eye movement control, and learned coordinate transformations. The model explains data from single neuron and psychophysical studies of covert visual attention shifts prior to eye movements. The model further clarifies how perceptual, attentional, and cognitive interactions among multiple brain regions (LGN, V1, V2, V3A, V4, MT, MST, PPC, LIP, ITp, ITa, SC may accomplish predictive remapping as part of the process whereby view-invariant object categories are learned. These results build upon earlier neural models of 3D vision and figure-ground separation and the learning of invariant object categories as the eyes freely scan a scene. A key process concerns how an object’s surface representation generates a form-fitting distribution of spatial attention, or attentional shroud, in parietal cortex that helps maintain the stability of multiple perceptual and cognitive processes. Predictive eye movement signals maintain the stability of the shroud, as well as of binocularly fused perceptual boundaries and surface representations.

  14. Binocular fusion and invariant category learning due to predictive remapping during scanning of a depthful scene with eye movements

    Grossberg, Stephen; Srinivasan, Karthik; Yazdanbakhsh, Arash

    2015-01-01

    How does the brain maintain stable fusion of 3D scenes when the eyes move? Every eye movement causes each retinal position to process a different set of scenic features, and thus the brain needs to binocularly fuse new combinations of features at each position after an eye movement. Despite these breaks in retinotopic fusion due to each movement, previously fused representations of a scene in depth often appear stable. The 3D ARTSCAN neural model proposes how the brain does this by unifying concepts about how multiple cortical areas in the What and Where cortical streams interact to coordinate processes of 3D boundary and surface perception, spatial attention, invariant object category learning, predictive remapping, eye movement control, and learned coordinate transformations. The model explains data from single neuron and psychophysical studies of covert visual attention shifts prior to eye movements. The model further clarifies how perceptual, attentional, and cognitive interactions among multiple brain regions (LGN, V1, V2, V3A, V4, MT, MST, PPC, LIP, ITp, ITa, SC) may accomplish predictive remapping as part of the process whereby view-invariant object categories are learned. These results build upon earlier neural models of 3D vision and figure-ground separation and the learning of invariant object categories as the eyes freely scan a scene. A key process concerns how an object's surface representation generates a form-fitting distribution of spatial attention, or attentional shroud, in parietal cortex that helps maintain the stability of multiple perceptual and cognitive processes. Predictive eye movement signals maintain the stability of the shroud, as well as of binocularly fused perceptual boundaries and surface representations. PMID:25642198

  15. Binocular fusion and invariant category learning due to predictive remapping during scanning of a depthful scene with eye movements.

    Grossberg, Stephen; Srinivasan, Karthik; Yazdanbakhsh, Arash

    2014-01-01

    How does the brain maintain stable fusion of 3D scenes when the eyes move? Every eye movement causes each retinal position to process a different set of scenic features, and thus the brain needs to binocularly fuse new combinations of features at each position after an eye movement. Despite these breaks in retinotopic fusion due to each movement, previously fused representations of a scene in depth often appear stable. The 3D ARTSCAN neural model proposes how the brain does this by unifying concepts about how multiple cortical areas in the What and Where cortical streams interact to coordinate processes of 3D boundary and surface perception, spatial attention, invariant object category learning, predictive remapping, eye movement control, and learned coordinate transformations. The model explains data from single neuron and psychophysical studies of covert visual attention shifts prior to eye movements. The model further clarifies how perceptual, attentional, and cognitive interactions among multiple brain regions (LGN, V1, V2, V3A, V4, MT, MST, PPC, LIP, ITp, ITa, SC) may accomplish predictive remapping as part of the process whereby view-invariant object categories are learned. These results build upon earlier neural models of 3D vision and figure-ground separation and the learning of invariant object categories as the eyes freely scan a scene. A key process concerns how an object's surface representation generates a form-fitting distribution of spatial attention, or attentional shroud, in parietal cortex that helps maintain the stability of multiple perceptual and cognitive processes. Predictive eye movement signals maintain the stability of the shroud, as well as of binocularly fused perceptual boundaries and surface representations.

  16. A review of Indirect Matrix Converter Topologies

    Salem Rahmani

    2015-08-01

    Full Text Available Abstract—Matrix Converter (MC is a modern direct AC/AC electrical power converter without dc-link capacitor. MC is operated in four quadrant, assuring a control of the output voltage, amplitude and frequency. The matrix converter has recently attracted significant attention among researchers and it has become increasing attractive for applications of wind energy conversion, military power supplies, induction motor drives, etc. Recently, different MC topologies have been proposed and developed which have their own advantages and disadvantages. Matrix converter can be classified as direct and indirect structures. The direct one has been elaborated in previous work. In this paper the indirect MCs are reviewed. Different characteristics of the indirect MC topologies are mentioned to show the strengths and weaknesses of such converter topologies.

  17. Indirect taxes on food in Southern Brazil

    Denize Mirian da Silva

    2013-12-01

    Full Text Available The objective of this paper is to estimate the indirect tax burden on food for ten income classes, based on income and household total expenditure in southern Brazil. Thus it can be seen as indirect taxes on foods affect the monetary income and consumption pattern of households. To reach the objectives proposed, will be used the Pintos-Payeras (2008 model. The database iscomposed by microdata from the Household Budgeting Survey (POF 2008-2009 and the tax regulations of the country and the southern states of Brazil. The results show that indirect taxes on food in Southern Brazil is regressive when based on income and expenditure of household , ie , the poorest people pay proportionately more taxes and have their consumption pattern highest taxed ICMS (Brazilian value added tax is the tax that contributes most to the regressivity.

  18. Ballistic fractures: indirect fracture to bone.

    Dougherty, Paul J; Sherman, Don; Dau, Nathan; Bir, Cynthia

    2011-11-01

    Two mechanisms of injury, the temporary cavity and the sonic wave, have been proposed to produce indirect fractures as a projectile passes nearby in tissue. The purpose of this study is to evaluate the temporal relationship of pressure waves using strain gauge technology and high-speed video to elucidate whether the sonic wave, the temporary cavity, or both are responsible for the formation of indirect fractures. Twenty-eight fresh frozen cadaveric diaphyseal tibia (2) and femurs (26) were implanted into ordnance gelatin blocks. Shots were fired using 9- and 5.56-mm bullets traversing through the gelatin only, passing close to the edge of the bone, but not touching, to produce an indirect fracture. High-speed video of the impact event was collected at 20,000 frames/s. Acquisition of the strain data were synchronized with the video at 20,000 Hz. The exact time of fracture was determined by analyzing and comparing the strain gauge output and video. Twenty-eight shots were fired, 2 with 9-mm bullets and 26 with 5.56-mm bullets. Eight indirect fractures that occurred were of a simple (oblique or wedge) pattern. Comparison of the average distance of the projectile from the bone was 9.68 mm (range, 3-20 mm) for fractured specimens and 15.15 mm (range, 7-28 mm) for nonfractured specimens (Student's t test, p = 0.036). In this study, indirect fractures were produced after passage of the projectile. Thus, the temporary cavity, not the sonic wave, was responsible for the indirect fractures.

  19. Indirect Comorbidity in Childhood and Adolescence

    William eCopeland

    2013-11-01

    Full Text Available Objective: Comorbidity between psychiatric disorders is common, but pairwise associations between two disorders may be explained by the presence of other diagnoses that are associated with both disorders or indirect comorbidity. Method: Comorbidities of common childhood psychiatric disorders were tested in three community samples of children ages 6 to 17 (8931 observations of 2965 subjects. Psychiatric disorder status in all three samples was assessed with the Child and Adolescent Psychiatric Assessment. Indirect comorbidity was defined as A-B associations that decreased from significance to nonsignificance after adjusting for other disorders. Results: All tested childhood psychiatric disorders were positively associated in bivariate analyses. After adjusting for comorbidities, many ssociations involving a behavioral disorder and an emotional disorder were attenuated suggesting indirect comorbidity. Generalized anxiety and depressive disorders displayed a very high level of overlap (adjusted OR=37.9. All analyses were rerun with depressive disorders grouped with generalized anxiety disorder in a single distress disorders category. In these revised models, all associations between and emotional disorder and a behavior disorder met our criteria for indirect comorbidity except for the association of oppositional defiant disorder with distress disorders (OR=11.3. Follow-up analyses suggested that the indirect associations were primarily accounted for by oppositional defiant disorder and the distress disorder category. There was little evidence of either sex differences or differences by developmental period Conclusions: After accounting for the overlap between depressive disorders with generalized anxiety disorder, direct comorbidity between emotional and behavioral disorders was uncommon. When there was evidence of indirect comorbidity, ODD and distress disorders were the key intermediary diagnoses accounting for the apparent associations.

  20. Indirect effects in dual radiation action

    Zaider, M.; Rossi, H.H.

    1988-01-01

    The basic aim in this paper is to establish the link between indirect effects of radiation action and the spatial distribution of radicals at the time of energy deposition as well as throughout subsequent diffusion and interaction. The fact that radicals diffuse for a finite distance before damaging a biomolecule has dramatic effects on their subsequent probability to result in lesions. Thus at very low DMSO concentrations, where p = 0.5, one expects - all other things being equal - some 75% of the lesions to result from indirect or semidirect lesions. The number calculated here is lower (15%), a direct result of the fact that such lesions involve proximity functions modulated by diffusion. At higher DMSO concentrations this percentage becomes progressively smaller, as expected. It appears thus that for low-LET radiation, the relative amount of indirect damage in single tracks (also termed intratrack or single events) action is very small. By contrast, intertrack (or two-event) contributions will have the ratio between direct and (indirect + semidirect) contributions given by p 2 /(1-p 2 ). The reason for this is that sublesions from different tracks are uniformly distributed throughout the cell nucleus; their probability of interaction should not depend on any previous diffusional processes. For the example given above (p = 0.5) they do expect 65% of intertrack (two-hit) lesions to have resulted from indirect or semidirect mechanisms. This contrast between the almost exclusively direct character of intratrack lesions and the dominant role of indirect action in intertrack lesions produced by low-LET radiation is an important conclusion of this study

  1. Global indirect aerosol effects: a review

    U. Lohmann

    2005-01-01

    Full Text Available Aerosols affect the climate system by changing cloud characteristics in many ways. They act as cloud condensation and ice nuclei, they may inhibit freezing and they could have an influence on the hydrological cycle. While the cloud albedo enhancement (Twomey effect of warm clouds received most attention so far and traditionally is the only indirect aerosol forcing considered in transient climate simulations, here we discuss the multitude of effects. Different approaches how the climatic implications of these aerosol effects can be estimated globally as well as improvements that are needed in global climate models in order to better represent indirect aerosol effects are discussed in this paper.

  2. Biomass Indirect Liquefaction Strategy Workshop Summary Report

    none,

    2014-07-01

    This report is based on the proceedings of the U.S. Department of Energy Bioenergy Technologies Office Biomass Indirect Liquefaction Strategy Workshop. The workshop, held March 20–21, 2014, in Golden, Colorado, discussed and detailed the research and development needs for biomass indirect liquefaction. Discussions focused on pathways that convert biomass-based syngas (or any carbon monoxide, hydrogen gaseous stream) to liquid intermediates (alcohols or acids) and further synthesize those intermediates to liquid hydrocarbons that are compatible as either a refinery feed or neat fuel.

  3. The power of indirect social ties

    Zuo, Xiang; Blackburn, Jeremy; Kourtellis, Nicolas; Skvoretz, John; Iamnitchi, Adriana

    2014-01-01

    While direct social ties have been intensely studied in the context of computer-mediated social networks, indirect ties (e.g., friends of friends) have seen little attention. Yet in real life, we often rely on friends of our friends for recommendations (of good doctors, good schools, or good babysitters), for introduction to a new job opportunity, and for many other occasional needs. In this work we attempt to 1) quantify the strength of indirect social ties, 2) validate it, and 3) empiricall...

  4. Indirect methods for wake potential integration

    Zagorodnov, I.

    2006-05-01

    The development of the modern accelerator and free-electron laser projects requires to consider wake fields of very short bunches in arbitrary three dimensional structures. To obtain the wake numerically by direct integration is difficult, since it takes a long time for the scattered fields to catch up to the bunch. On the other hand no general algorithm for indirect wake field integration is available in the literature so far. In this paper we review the know indirect methods to compute wake potentials in rotationally symmetric and cavity-like three dimensional structures. For arbitrary three dimensional geometries we introduce several new techniques and test them numerically. (Orig.)

  5. Development of an indirect spectrophotometric method for ...

    A simple and rapid indirect spectrophotometric method for determination of ... of the colored product was measured at 405 nm and pH 3 against a reagent blank. ... The limit of detection and quantification were found to be 0.20±0.03 and ...

  6. Indirect processes in electron-ion scattering

    Bottcher, C.; Griffin, D.C.; Pindzola, M.S.; Phaneuf, R.A.

    1983-10-01

    A summary is given of an informal workshop held at Oak Ridge National Laboratory on June 22-23, 1983, in which the current status of theoretical calculations of indirect processes in electron-ion scattering was reviewed. Processes of particular interest in astrophysical and fusion plasmas were emphasized. Topics discussed include atomic structure effects, electron-impact ionization, and dielectronic recombination

  7. Indirect effects of recreation on wildlife

    David N. Cole; Peter B. Landres

    1995-01-01

    Most of this book focuses on direct impacts to wildlife that result from contact with people. The purpose of our chapter is to provide a broad overview of the indirect influences that recreation has on wildlife. Recreational activities can change the habitat of an animal. This, in turn, affects the behavior, survival, reproduction, and distribution of individuals....

  8. 46 CFR 154.1720 - Indirect refrigeration.

    2010-10-01

    ... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Special Design and Operating Requirements § 154.1720 Indirect refrigeration. A refrigeration system that is used to cool acetaldehyde, ethylene...

  9. Indirect processes in electron-ion scattering

    Bottcher, C.; Griffin, D.C.; Pindzola, M.S.; Phaneuf, R.A.

    1983-10-01

    A summary is given of an informal workshop held at Oak Ridge National Laboratory on June 22-23, 1983, in which the current status of theoretical calculations of indirect processes in electron-ion scattering was reviewed. Processes of particular interest in astrophysical and fusion plasmas were emphasized. Topics discussed include atomic structure effects, electron-impact ionization, and dielectronic recombination.

  10. 27 CFR 6.32 - Indirect interest.

    2010-04-01

    ... OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail Property § 6.32 Indirect interest. Industry member interest in retail property includes any interest acquired by corporate officials, partners, employees or other representatives of the industry member. Any interest in retail property...

  11. 27 CFR 6.26 - Indirect interest.

    2010-04-01

    ... OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail License § 6.26 Indirect interest. Industry member interest in retail licenses includes any interest acquired by corporate officials, partners, employees or other representatives of the industry member. Any interest in a retail license...

  12. Indirect Costs: Daily Bread, Cake, or Cracker.

    Lucas, Robert A.

    1988-01-01

    The tradition of negotiating indirect costs in grants should be abandoned, and research administrators should instead offer different levels of service depending on what the sponsor wants to spend. Three levels of overhead rate are suggested (super, regular, and economy) and their corresponding levels of service are defined. (MSE)

  13. Epidemic spreading through direct and indirect interactions.

    Ganguly, Niloy; Krueger, Tyll; Mukherjee, Animesh; Saha, Sudipta

    2014-09-01

    In this paper we study the susceptible-infected-susceptible epidemic dynamics, considering a specialized setting where popular places (termed passive entities) are visited by agents (termed active entities). We consider two types of spreading dynamics: direct spreading, where the active entities infect each other while visiting the passive entities, and indirect spreading, where the passive entities act as carriers and the infection is spread via them. We investigate in particular the effect of selection strategy, i.e., the way passive entities are chosen, in the spread of epidemics. We introduce a mathematical framework to study the effect of an arbitrary selection strategy and derive formulas for prevalence, extinction probabilities, and epidemic thresholds for both indirect and direct spreading. We also obtain a very simple relationship between the extinction probability and the prevalence. We pay special attention to preferential selection and derive exact formulas. The analysis reveals that an increase in the diversity in the selection process lowers the epidemic thresholds. Comparing the direct and indirect spreading, we identify regions in the parameter space where the prevalence of the indirect spreading is higher than the direct one.

  14. Indirect Determination of the sigma - omega

    Ulfkjær, J. P.; Brincker, Rune

    . The beams where submitted to three-point bending in a servo-controlled materials testing system. The constitutive parameters in the fictitious crack model were determined by using three different indirect techniques, which are described and evaluated. The results show that the fracture energy is increasing...

  15. Comprehension Process of Second Language Indirect Requests.

    Takahashi, Satomi; Roitblat, Herbert L.

    1994-01-01

    Examines the comprehension of English conventional indirect requests by native English speakers and Japanese learners of English. Subjects read stories inducing either a conventional or a literal interpretation of a priming sentence. Results suggest that both native and nonnative speakers process both meanings of an ambiguous conventional request.…

  16. 48 CFR 31.203 - Indirect costs.

    2010-10-01

    ... fiscal year used for financial reporting purposes in accordance with generally accepted accounting... contract or other work, indirect costs are those remaining to be allocated to intermediate or two or more... basis of the benefits accruing to intermediate and final cost objectives. When substantially the same...

  17. Scene independent real-time indirect illumination

    Frisvad, Jeppe Revall; Christensen, Niels Jørgen; Falster, Peter

    2005-01-01

    A novel method for real-time simulation of indirect illumination is presented in this paper. The method, which we call Direct Radiance Mapping (DRM), is based on basal radiance calculations and does not impose any restrictions on scene geometry or dynamics. This makes the method tractable for rea...

  18. Two distinct neural mechanisms underlying indirect reciprocity.

    Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

    2014-03-18

    Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards.

  19. INDIRECT LABOR COSTS AND IMPLICATIONS FOR OVERHEAD ALLOCATION

    Bea Chiang

    2013-01-01

    Cost accounting typically allocates indirect labor cost to cost object based on direct labor hours. The allocation process implicitly assumes that indirect labor costs vary proportionally with direct labor hours. The assumption of a linear relationship between indirect and direct labor is particularly suspicious at low production volume levels because there tends to be a fixed component in indirect labor. The linearity assumption is also challenged by recent increasing complexity of indirect ...

  20. The Indirect cost of illness in Africa

    Joses Muthuri Kirigia

    2018-06-01

    Full Text Available Background: The current study estimated (a the indirect costs associated with non-fatal disability and premature death across a wide range of diseases and health conditions in Africa in 2015 and (b the potential savings that could be accrued if countries were to meet the 3 health targets of the substainable development goal (SDG compared to the costs under the status quo. Methods: This study used the lost output or human capital approach to quantify the gross domestic product (GDP losses associated with the disability-adjusted-life-years (DALYs lost due to all causes by age group as well as by country economic classification (Group 1: 10 high/upper-middle income countries; Group 2: 17 lower-middle income countries; and Group 3: 27 low income countries. Results: The expected indirect cost of the 704,765,879 DALYs lost in Africa in 2015 was Int$ 2,983,187,560,197. Of this amount, 25.17%, 57.84% and 16.99% were incurred by the economies of the countries comprising Group 1, Group 2 and Group 3, respectively. Of the total continental indirect cost, 36.9%, 10.5%, 13.7%, 17.0%, 7.6%, 6.8% and 7.5% were associated with people aged 0-4, 5-14, 15-29, 30-49, 50-59, 60-69 and 70 years or older, respectively. Most of the total indirect cost (56.61% was attributable to maternal conditions, AIDS, tuberculosis (TB, malaria, neglected tropicald diseases (NTDs, non-communicable diseases and traffic injuries. Approximately half (47% of this cost could be avoided (or saved every year if the 3 (health targets of the SDG were fully met. Conclusion: The study estimated the total indirect cost of illness due to all causes by age group and country economic classification. The annual indirect cost is substantial. The findings contained in this paper suggest that health system strengthening should focus on both rich and poor countries, people of all ages and specific disease categories.

  1. Cruel intentions on television and in real life: can viewing indirect aggression increase viewers' subsequent indirect aggression?

    Coyne, Sarah M; Archer, John; Eslea, Mike

    2004-07-01

    Numerous studies have shown that viewing violence in the media can influence an individual's subsequent aggression, but none have examined the effect of viewing indirect aggression. This study examines the immediate effect of viewing indirect and direct aggression on subsequent indirect aggression among 199 children ages 11 to 14 years. They were shown an indirect, direct, or no-aggression video and their subsequent indirect aggression was measured by negative evaluation of a confederate and responses to a vignette. Participants viewing indirect or direct aggression gave a more negative evaluation of and less money to a confederate than participants viewing no-aggression. Participants viewing indirect aggression gave less money to the confederate than those viewing direct aggression. Participants viewing indirect aggression gave more indirectly aggressive responses to an ambiguous situation and participants viewing direct aggression gave more directly aggressive responses. This study provides the first evidence that viewing indirect aggression in the media can have an immediate impact on subsequent aggression.

  2. Disfunciones visuo-perceptivas, oculomotoras, acomodativas y binoculares en niños con trastornos por déficit de atención e hiperactividad

    Pardo Pérez, María Carmen

    2009-01-01

    1) Determinar el grado de desarrollo de las habilidades visuoperceptivas, oculomotoras, acomodativas y binoculares en estudiantes con TDAH. 2) Comparar las habilidades visuales y visuoperceptivas entre un grupo de estudiantes con TDAH y otro que no presenta este trastorno. 3) Analizar qué habilidades visuoperceptivas (discriminación, memoria visual, figura-fondo, integración visual…) y oculomotoras presentan unos valores más deteriorados en el grupo de estudiantes que presentan...

  3. Microsurgical Clipping of an Anterior Communicating Artery Aneurysm Using a Novel Robotic Visualization Tool in Lieu of the Binocular Operating Microscope: Operative Video.

    Klinger, Daniel R; Reinard, Kevin A; Ajayi, Olaide O; Delashaw, Johnny B

    2018-01-01

    The binocular operating microscope has been the visualization instrument of choice for microsurgical clipping of intracranial aneurysms for many decades. To discuss recent technological advances that have provided novel visualization tools, which may prove to be superior to the binocular operating microscope in many regards. We present an operative video and our operative experience with the BrightMatterTM Servo System (Synaptive Medical, Toronto, Ontario, Canada) during the microsurgical clipping of an anterior communicating artery aneurysm. To the best of our knowledge, the use of this device for the microsurgical clipping of an intracranial aneurysm has never been described in the literature. The BrightMatterTM Servo System (Synaptive Medical) is a surgical exoscope which avoids many of the ergonomic constraints of the binocular operating microscope, but is associated with a steep learning curve. The BrightMatterTM Servo System (Synaptive Medical) is a maneuverable surgical exoscope that is positioned with a directional aiming device and a surgeon-controlled foot pedal. While utilizing this device comes with a steep learning curve typical of any new technology, the BrightMatterTM Servo System (Synaptive Medical) has several advantages over the conventional surgical microscope, which include a relatively unobstructed surgical field, provision of high-definition images, and visualization of difficult angles/trajectories. This device can easily be utilized as a visualization tool for a variety of cranial and spinal procedures in lieu of the binocular operating microscope. We anticipate that this technology will soon become an integral part of the neurosurgeon's armamentarium. Copyright © 2017 by the Congress of Neurological Surgeons

  4. Indirect genetic effects and kin recognition

    Alemu, Setegn Worku; Berg, Peer; Janss, Luc

    2014-01-01

    Social interactions among individuals are widespread, both in natural and domestic populations. As a result, trait values of individuals may be affected by genes in other individuals, a phenomenon known as indirect genetic effects (IGEs). IGEs can be estimated using linear mixed models. The tradi......Social interactions among individuals are widespread, both in natural and domestic populations. As a result, trait values of individuals may be affected by genes in other individuals, a phenomenon known as indirect genetic effects (IGEs). IGEs can be estimated using linear mixed models...... present a reduced model that yields estimates of the total heritable effects on kin, on non-kin and on all social partners of an individual, as well as the total heritable variance for response to selection. Finally we discuss the consequences of analysing data in which IGEs depend on relatedness using...

  5. Lack of indirect sensitization in vivo

    Hetzel, F.W.; Avery, K.; Mensinger, M.; Frinak, S.; Tidwell, C.

    1985-01-01

    The possible utility of respiratory inhibiting drugs as indirect radiation sensitizers has been investigated in both in vitro and in vivo systems. In vitro studies were conducted in V79 monolayer and spheroid cultures examining both respiratory inhibition and radiation survival as end points. These drugs (BCNU, Mustargen and Chlorambucil) were found to be potent respiratory inhibitors and, in the spheroid system, to be effective indirect radiation sensitizers with enhancement ratios of approximately 2.0. In vivo studies with these drugs have also been conducted in a C/sub 3/H mouse MCa tumor system to determine if the same reoxygenation effect observed in spheroids could be demonstrated in the solid tumor system. Detailed microelectrode studies, employing each drug at its LD/sub 10/ level, have been unable to demonstrate any drug induced reoxygenation for any of the drugs tested. Complete details are presented

  6. Direct or indirect - that is the question!

    Pallesen, Ulla

    2016-01-01

    Time has passed since the prevention of caries was performed by extending cavity preparations wide in the tooth and below the gingiva. In the same period adhesive techniques have improved and nowadays made it possible to extend the indications for direct composite resin restorations, also when...... rather destroyed teeth need to be restored. Although much can be solved by direct fillings and thereby make treatments less invasive for the tooth and less expensive for the patient, there still will be teeth, where the prognosis is improved, if an indirect restoration in terms of an inlay, onlay...... or crown is made. Factors as remaining tooth structure, endodontic treatment, number of teeth, caries risk, para-functional habits, material properties, economy etc. will all have an influence, when the dentist guides the patient to choose the best solution. What is best for the tooth – direct or indirect...

  7. Social intervention and risk reduction - indirect countermeasures

    Higgins, N.A.; Morrey, M.

    1996-01-01

    An indirect countermeasure (IC) is an action which is intended to mitigate detrimental effects experienced by individuals or the community after an accident. Indirect countermeasures (ICs) achieve this, both by averting radiation risks arising from the accident, but by removing or reducing other risks and sources of stress or harm to which the community may be subject. ICs naturally fall into two categories: social action ICs, which range from introducing compensation payments to providing information centres; and risk reducing ICs which mitigate risks to which the population might be exposed, such as radon. By including a consideration of ICs in an assessment of the optimal response, it is likely that a decision maker will become aware of a greater range of harms and benefits that might result from the application of a countermeasure. The decision maker will then be in a better position to judge the appropriateness of any action. (author)

  8. Studies on direct and indirect electrochemical immunoassays

    Buckley, Eileen

    1989-01-01

    Two approaches to electrochemical immunoassay are reported. The first approach was an indirect method, involving an electroactive, enzyme-catalysed, substrate to product reaction. Conditions were optimised for the amperometric detection of para-aminophenol, the electroactive product of the alkaline phosphatase catalysed hydrolysis of a new substrate, p-aminophenylphosphate, after separation by HPLC. The second approach involved the direct electrochemical detection of an immunoglo...

  9. Color indirect effects on melatonin regulation

    Mian, Tian; Liu, Timon C.; Li, Yan

    2002-04-01

    Color indirect effect (CIE) is referred to as the physiological and psychological effects of color resulting from color vision. In previous papers, we have studied CIE from the viewpoints of the integrated western and Chinese traditional medicine, put forward the color-autonomic- nervous-subsystem model (CAM), and provided its time-theory foundation. In this paper, we applied it to study light effects on melatonin regulation in humans, and suggested that it is CIE that mediates light effects on melatonin suppression.

  10. Software Prefetching for Indirect Memory Accesses

    Ainsworth, Sam; Jones, Timothy

    2017-01-01

    Many modern data processing and HPC workloads are heavily memory-latency bound. A tempting proposition to solve this is software prefetching, where special non-blocking loads are used to bring data into the cache hierarchy just before being required. However, these are difficult to insert to effectively improve performance, and techniques for automatic insertion are currently limited. This paper develops a novel compiler pass to automatically generate software prefetches for indirect mem...

  11. Draft of textbook focused on indirect taxes

    Nováková, Hana

    2012-01-01

    The diploma thesis is about draft of textbook which is focused on indirect taxes for business school. The thesis is divided into theoretical and practical part. The theoretical part is focused on teaching tax issues at business school. Readers are introduced with basic studying documents, for example framework educational program and school educational program. In the following part I have conducted didactic analysis of curriculum and textbook of economics for business schools. The draft of t...

  12. Comment traduire en japonais les styles indirect et indirect libre de Madame Bovary ?

    Hisaki Sawasaki

    2012-03-01

    Full Text Available Parmi les difficultés rencontrées lors de la traduction des textes littéraires occidentaux, en japonais, nous examinons le problème des styles indirect et indirect libre. Pour cela, en effectuant une petite mise au point grammaticale, nous comparons sept traductions de Madame Bovary de Gustave Flaubert, dont les dates de parution s’étendent sur une cinquantaine d’années. Cette période s’apparente, de notre point de vue, à un long itinéraire pour assimiler la notion occidentale des styles direct et indirect, tout en la conciliant avec les particularités du japonais. D’un autre côté, ce travail acharné des traducteurs a influencé quelque peu la langue japonaise. On trouve dans l’annexe tous les textes en japonais examinés.We will examine the difficulties met when translating Western literary texts in Japanese, in particular the problem of indirect and free indirect styles. We will define the grammatical issue and compare seven translations of Madame Bovary, published over a fifty year period. This time can be likened to a long path taken to digest the Western notion of direct and indirect styles, while reconciling it with Japanese language characteristics. On the other hand the translators’ relentless work has somewhat influenced the Japanese language. The annex will present all the Japanese texts examined.

  13. Indirect carotid cavernous fistula mimicking ocular myasthenia.

    Leishangthem, Lakshmi; Satti, Sudhakar Reddy

    2017-10-19

    71-year-old woman with progressive left-sided, monocular diplopia and ptosis. Her symptoms mimicked ocular myasthenia, but she had an indirect carotid cavernous fistula (CCF). She was diagnosed with monocular myasthenia gravis (negative acetylcholinesterase antibody) after a positive ice test and started on Mestinon and underwent a thymectomy complicated by a brachial plexus injury. Months later, she developed left-sided proptosis and ocular bruit. She was urgently referred to neuro-interventional surgery and was diagnosed with an indirect high-flow left CCF, which was treated with Onyx liquid and platinum coil embolisation. Mestinon was discontinued. Her ophthalmic symptoms resolved. However, she was left with a residual left arm and hand hemiparesis and dysmetria secondary to a brachial plexus injury. Indirect CCF usually can present with subtle and progressive symptoms leading to delayed diagnosis or misdiagnosis. It is important for ophthalmologists to consider this differential in a patient with progressive ocular symptoms. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. Indirect Comprehensive Review Board (ICRB). Final Report

    1996-12-01

    Lockheed Martin Idaho Technologies Company (LMITCO) used a systems engineering approach to take the first step toward defining a requirements baseline for all indirect work at the Idaho National Engineering Laboratory. The intent of this effort was to define the requirements for indirect work, identify the activities necessary to meet the requirements, and to produce defensible cost estimates for the work. The result of this effort is a scrubbed-down, defensible budget for all indirect work in FY 1997. Buying power for each dollar of direct work was increased by $.02. Recommendations are identified for improvements to this process in FY 1998. The purpose of this report is twofold. First is to report the final results of the 1996 ICRB process, and second is to document the process used such that incremental improvements may be made in future years. Objectives, processes, and approaches are described to provide a trail for future boards. Appendices contain copies of board composition, documentation of the process, as well as the actual training materials

  15. Interactive indirect illumination using adaptive multiresolution splatting.

    Nichols, Greg; Wyman, Chris

    2010-01-01

    Global illumination provides a visual richness not achievable with the direct illumination models used by most interactive applications. To generate global effects, numerous approximations attempt to reduce global illumination costs to levels feasible in interactive contexts. One such approximation, reflective shadow maps, samples a shadow map to identify secondary light sources whose contributions are splatted into eye space. This splatting introduces significant overdraw that is usually reduced by artificially shrinking each splat's radius of influence. This paper introduces a new multiresolution approach for interactively splatting indirect illumination. Instead of reducing GPU fill rate by reducing splat size, we reduce fill rate by rendering splats into a multiresolution buffer. This takes advantage of the low-frequency nature of diffuse and glossy indirect lighting, allowing rendering of indirect contributions at low resolution where lighting changes slowly and at high-resolution near discontinuities. Because this multiresolution rendering occurs on a per-splat basis, we can significantly reduce fill rate without arbitrarily clipping splat contributions below a given threshold-those regions simply are rendered at a coarse resolution.

  16. Spatially indirect excitons in coupled quantum wells

    Lai, Chih-Wei Eddy [Univ. of California, Berkeley, CA (United States)

    2004-03-01

    Microscopic quantum phenomena such as interference or phase coherence between different quantum states are rarely manifest in macroscopic systems due to a lack of significant correlation between different states. An exciton system is one candidate for observation of possible quantum collective effects. In the dilute limit, excitons in semiconductors behave as bosons and are expected to undergo Bose-Einstein condensation (BEC) at a temperature several orders of magnitude higher than for atomic BEC because of their light mass. Furthermore, well-developed modern semiconductor technologies offer flexible manipulations of an exciton system. Realization of BEC in solid-state systems can thus provide new opportunities for macroscopic quantum coherence research. In semiconductor coupled quantum wells (CQW) under across-well static electric field, excitons exist as separately confined electron-hole pairs. These spatially indirect excitons exhibit a radiative recombination time much longer than their thermal relaxation time a unique feature in direct band gap semiconductor based structures. Their mutual repulsive dipole interaction further stabilizes the exciton system at low temperature and screens in-plane disorder more effectively. All these features make indirect excitons in CQW a promising system to search for quantum collective effects. Properties of indirect excitons in CQW have been analyzed and investigated extensively. The experimental results based on time-integrated or time-resolved spatially-resolved photoluminescence (PL) spectroscopy and imaging are reported in two categories. (i) Generic indirect exciton systems: general properties of indirect excitons such as the dependence of exciton energy and lifetime on electric fields and densities were examined. (ii) Quasi-two-dimensional confined exciton systems: highly statistically degenerate exciton systems containing more than tens of thousands of excitons within areas as small as (10 micrometer)2 were

  17. Towards free 3D end-point control for robotic-assisted human reaching using binocular eye tracking.

    Maimon-Dror, Roni O; Fernandez-Quesada, Jorge; Zito, Giuseppe A; Konnaris, Charalambos; Dziemian, Sabine; Faisal, A Aldo

    2017-07-01

    Eye-movements are the only directly observable behavioural signals that are highly correlated with actions at the task level, and proactive of body movements and thus reflect action intentions. Moreover, eye movements are preserved in many movement disorders leading to paralysis (or amputees) from stroke, spinal cord injury, Parkinson's disease, multiple sclerosis, and muscular dystrophy among others. Despite this benefit, eye tracking is not widely used as control interface for robotic interfaces in movement impaired patients due to poor human-robot interfaces. We demonstrate here how combining 3D gaze tracking using our GT3D binocular eye tracker with custom designed 3D head tracking system and calibration method enables continuous 3D end-point control of a robotic arm support system. The users can move their own hand to any location of the workspace by simple looking at the target and winking once. This purely eye tracking based system enables the end-user to retain free head movement and yet achieves high spatial end point accuracy in the order of 6 cm RMSE error in each dimension and standard deviation of 4 cm. 3D calibration is achieved by moving the robot along a 3 dimensional space filling Peano curve while the user is tracking it with their eyes. This results in a fully automated calibration procedure that yields several thousand calibration points versus standard approaches using a dozen points, resulting in beyond state-of-the-art 3D accuracy and precision.

  18. Indirect measurements of X-ray spectra

    Mainardi, R.T.

    2006-01-01

    To the effects of measuring the spectral distribution of the radiation emitted by the x-ray tubes and electron accelerators, numerous procedures that are grouped in two big categories exist at the present time: direct and indirect methods. The first ones use high resolution detectors that should be positioned, together with the appropriate collimator, in the direction of the x ray beam. The user should be an expert in the use and correction of the obtained data by the different effects that affect the detector operation such as efficiency and resolution in terms of the energy of the detected radiation. The indirect procedures, although its are more simple to use, its also require a considerable space along the beam to position the ionization chamber and the necessary absorbents to construct by this way the denominated attenuation curve. We will analyze the operation principle of the indirect methods and a new proposal in which such important novelties are introduced as the beam dispersion to avoid to measure along the main beam and that of determination of the attenuation curve in simultaneous form. By this way, with a single shot of the tube, the attenuation curve is measured, being necessary at most a shot of additional calibration to know the relative response of the detectors used in the experimental array. The physical processes involved in the obtaining of an attenuation curve are very well well-known and this it finishes it can be theoretically calculated if the analytic form of the spectrum is supposed well-known. Finally, we will see a spectra reconstruction example with the Kramers parametric form and comparisons with numeric simulations carried out with broadly validated programs as well as the possibility of the use of solid state dosemeters in the obtention of the attenuation curve. (Author)

  19. Indirect quantum tomography of quadratic Hamiltonians

    Burgarth, Daniel [Institute for Mathematical Sciences, Imperial College London, London SW7 2PG (United Kingdom); Maruyama, Koji; Nori, Franco, E-mail: daniel@burgarth.de, E-mail: kmaruyama@riken.jp [Advanced Science Institute, RIKEN, Wako-shi, Saitama 351-0198 (Japan)

    2011-01-15

    A number of many-body problems can be formulated using Hamiltonians that are quadratic in the creation and annihilation operators. Here, we show how such quadratic Hamiltonians can be efficiently estimated indirectly, employing very few resources. We found that almost all the properties of the Hamiltonian are determined by its surface and that these properties can be measured even if the system can only be initialized to a mixed state. Therefore, our method can be applied to various physical models, with important examples including coupled nano-mechanical oscillators, hopping fermions in optical lattices and transverse Ising chains.

  20. Indirect evidence of calcitonin secretion in man.

    Caniggia, A; Gennari, C; Vattimo, A; Nardi, P; Nuti, R

    1976-09-01

    1. The effect of calcitonin, a large amount of calcium given orally, pentagastrin and glucagon on plasma 47Ca radioactivity curves in subjects pretreated with 47Ca was examined. 2. A sudden increase of plasma radioactivity after intravenous administration of calcitonin and pentagastrin and after the oral calcium load was observed in normal subjects; the intravenous infusion of glucagon was less effective. 3. Two thyroparathyroidectomized patients who responded to the calcitonin infusion did not respond to the oral calcium load. 4. These data may be considered to offer indirect evidence of endogenous calcitonin secretion in man.

  1. Third European Company Survey – Direct and indirect employee participation

    Akkerman, Agnes; Sluiter, Roderick; Jansen, Giedo

    2015-01-01

    This report studies practices in EU establishments for direct and indirect employee participation in decision-making. Indirect employee participation is the involvement of employee representatives in decision-making processes, while direct employee participation describes direct interaction between

  2. Indirect Estimation of Selected Measures of Fertility and Marital ...

    DLHS6

    2018-01-09

    Jan 9, 2018 ... marital status distribution data of India especially of the 2011 census in deriving indirectly the fertility measures .... 2011 Census, Economic and Political weekly, EPW Vol. ... Indirect Estimates of Total Fertility Rate Using Child.

  3. THE INDIRECT OBJECT (IO) – ALBANIAN AND ENGLISH

    Shkelqim Millaku; Xhevahire Topanica

    2016-01-01

    The aim of this study is too corporate the function of the indirect object between Albanian and English language. The function and the Albanian typical case for indirect object are dative and ablative. This grammatical phenomena is the full contrast between two languages because in English language doesn’t exist dative and ablative us in Albanian. In Albanian and English language, the indirect object is more heterogenic than the direct object. The indirect (direct) object in both of languages...

  4. On the Relative Size of Direct and Indirect Taxation

    Soldatos, Gerasimos T.

    2014-01-01

    Modifying the standard analytical apparatuses for direct and indirect tax evasion to incorporate forward indirect tax shift in a monopolistically competitive environment, this paper maintains that indirect tax evasion would exceed for sure direct tax evasion only under consumer risk neutrality and a tax policy zeroing the tax shift. Also, in the presence of tax evasion, there cannot be optimal direct-indirect tax mix, because tax evasion is accompanied by uncertainty and hence, nonlinearities...

  5. Microdosimetric concepts for indirect radiation reactions

    Pohlit, W.

    1976-01-01

    It is the aim of microdosimetric models to get information about the influence of microscopic energy deposition by radiation on radiation reactions. Two parameters are always of interest: the energy necessary to produce a certain reaction and the volume in which this energy has to be desposited. In the simple case of an aqueous solution with point targets a complete description of radiation reactions in targets with various concentrations can be given. This model takes into consideration the distinct energy deposition on the particle track, diffusion of radicals and a mean energy necessary for a certain reaction at the target. Typical dose effect curves are obtained which allow the determination of all these quantities from experiments. The model has been tested with the oxydation of iron atoms in aqueous solutions and has been applied for more complex targets such as different alcohols and amino acids. The oxygen consumption in these reactions is used as an easy method for continuous measurement of these indirect reactions. It is the aim of such experiments to get enough quantitative microscopic data on indirect radiation reactions that these reactions can also be followed in living cells

  6. The indirect strategies of internationalization of companies

    Đorđević Momčilo

    2012-01-01

    Full Text Available The subject of this work are, as mentioned in the title, the indirect strategies of internationalization of companies. The first part talks about the new business environment, the factors that lead to changes and their implications. It is at the same time the business context, which must be taken into consideration that determines the success of companies in the new business environment. In this paper, the emphasis is on company business in international markets, and the selection of appropriate strategies of internationalization, which will be responsible for this new business environment. There are many reasons that are discussed in this paper, and would rather indicate that partners from different countries to accept different strategies, rather than opting for a strategy of export, or a strategy of direct investments abroad. The dynamic technical and technological development, and its universal impact, among other relevant factors, put in the first place the importance of different strategies which is achieved through technology transfer, knowledge and experience whereby the exports, as a classic strategy of involvement in international trade, becomes significantly more difficult. Also, the internationalization of enterprises through direct investment abroad, involves many difficulties related to fitting in a foreign enterprise environment, and a high risk strategy. In addition, there is still a large number of countries do not allow wholly owned foreign enterprises. The paper discusses the value of various indirect internationalization strategy, which may be useful for those domestic companies that are in front of problem the choice of acceptable strategies of internationalization.

  7. Indirect costs of teaching in Canadian hospitals.

    MacKenzie, T A; Willan, A R; Cox, M A; Green, A

    1991-01-01

    We sought to determine whether there are indirect costs of teaching in Canadian hospitals. To examine cost differences between teaching and nonteaching hospitals we estimated two cost functions: cost per case and cost per patient-day (dependent variables). The independent variables were number of beds, occupancy rate, teaching ratio (number of residents and interns per 100 beds), province, urbanicity (the population density of the county in which the hospital was situated) and wage index. Within each hospital we categorized a random sample of patient discharges according to case mix and severity of illness using age and standard diagnosis and procedure codes. Teaching ratio and case severity were each highly correlated positively with the dependent variables. The other variables that led to higher costs in teaching hospitals were wage rates and number of beds. Our regression model could serve as the basis of a reimbursement system, adjusted for severity and teaching status, particularly in provinces moving toward introducing case-weighting mechanisms into their payment model. Even if teaching hospitals were paid more than nonteaching hospitals because of the difference in the severity of illness there should be an additional allowance to cover the indirect costs of teaching. PMID:1898870

  8. Cooperation under indirect reciprocity and imitative trust.

    Saavedra, Serguei; Smith, David; Reed-Tsochas, Felix

    2010-10-27

    Indirect reciprocity, a key concept in behavioral experiments and evolutionary game theory, provides a mechanism that allows reciprocal altruism to emerge in a population of self-regarding individuals even when repeated interactions between pairs of actors are unlikely. Recent empirical evidence show that humans typically follow complex assessment strategies involving both reciprocity and social imitation when making cooperative decisions. However, currently, we have no systematic understanding of how imitation, a mechanism that may also generate negative effects via a process of cumulative advantage, affects cooperation when repeated interactions are unlikely or information about a recipient's reputation is unavailable. Here we extend existing evolutionary models, which use an image score for reputation to track how individuals cooperate by contributing resources, by introducing a new imitative-trust score, which tracks whether actors have been the recipients of cooperation in the past. We show that imitative trust can co-exist with indirect reciprocity mechanisms up to a threshold and then cooperation reverses -revealing the elusive nature of cooperation. Moreover, we find that when information about a recipient's reputation is limited, trusting the action of third parties towards her (i.e. imitating) does favor a higher collective cooperation compared to random-trusting and share-alike mechanisms. We believe these results shed new light on the factors favoring social imitation as an adaptive mechanism in populations of cooperating social actors.

  9. Cooperation under indirect reciprocity and imitative trust.

    Serguei Saavedra

    Full Text Available Indirect reciprocity, a key concept in behavioral experiments and evolutionary game theory, provides a mechanism that allows reciprocal altruism to emerge in a population of self-regarding individuals even when repeated interactions between pairs of actors are unlikely. Recent empirical evidence show that humans typically follow complex assessment strategies involving both reciprocity and social imitation when making cooperative decisions. However, currently, we have no systematic understanding of how imitation, a mechanism that may also generate negative effects via a process of cumulative advantage, affects cooperation when repeated interactions are unlikely or information about a recipient's reputation is unavailable. Here we extend existing evolutionary models, which use an image score for reputation to track how individuals cooperate by contributing resources, by introducing a new imitative-trust score, which tracks whether actors have been the recipients of cooperation in the past. We show that imitative trust can co-exist with indirect reciprocity mechanisms up to a threshold and then cooperation reverses -revealing the elusive nature of cooperation. Moreover, we find that when information about a recipient's reputation is limited, trusting the action of third parties towards her (i.e. imitating does favor a higher collective cooperation compared to random-trusting and share-alike mechanisms. We believe these results shed new light on the factors favoring social imitation as an adaptive mechanism in populations of cooperating social actors.

  10. 21 CFR 870.3640 - Indirect pacemaker generator function analyzer.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indirect pacemaker generator function analyzer... Indirect pacemaker generator function analyzer. (a) Identification. An indirect pacemaker generator function analyzer is an electrically powered device that is used to determine pacemaker function or...

  11. System markets: Indirect network effects in action, or inaction?

    J.L.G. Binken (Jeroen)

    2010-01-01

    textabstractIn this dissertation, I empirically examine system markets up close. More specifically I examine indirect network effects, both demand-side and supply-side indirect network effects. Indirect network effects are the source of positive feedback in system markets, or so network effect

  12. Disambiguation of Necker cube rotation by monocular and binocular depth cues: relative effectiveness for establishing long-term bias.

    Harrison, Sarah J; Backus, Benjamin T; Jain, Anshul

    2011-05-11

    The apparent direction of rotation of perceptually bistable wire-frame (Necker) cubes can be conditioned to depend on retinal location by interleaving their presentation with cubes that are disambiguated by depth cues (Haijiang, Saunders, Stone, & Backus, 2006; Harrison & Backus, 2010a). The long-term nature of the learned bias is demonstrated by resistance to counter-conditioning on a consecutive day. In previous work, either binocular disparity and occlusion, or a combination of monocular depth cues that included occlusion, internal occlusion, haze, and depth-from-shading, were used to control the rotation direction of disambiguated cubes. Here, we test the relative effectiveness of these two sets of depth cues in establishing the retinal location bias. Both cue sets were highly effective in establishing a perceptual bias on Day 1 as measured by the perceived rotation direction of ambiguous cubes. The effect of counter-conditioning on Day 2, on perceptual outcome for ambiguous cubes, was independent of whether the cue set was the same or different as Day 1. This invariance suggests that a common neural population instantiates the bias for rotation direction, regardless of the cue set used. However, in a further experiment where only disambiguated cubes were presented on Day 1, perceptual outcome of ambiguous cubes during Day 2 counter-conditioning showed that the monocular-only cue set was in fact more effective than disparity-plus-occlusion for causing long-term learning of the bias. These results can be reconciled if the conditioning effect of Day 1 ambiguous trials in the first experiment is taken into account (Harrison & Backus, 2010b). We suggest that monocular disambiguation leads to stronger bias either because it more strongly activates a single neural population that is necessary for perceiving rotation, or because ambiguous stimuli engage cortical areas that are also engaged by monocularly disambiguated stimuli but not by disparity-disambiguated stimuli

  13. Large Binocular Telescope/LUCIFER spectroscopy: kinematics of a compact early-type galaxy at z ≃ 1.4

    Longhetti, M.; Saracco, P.; Gargiulo, A.; Tamburri, S.; Lonoce, I.

    2014-04-01

    We present a high signal-to-noise ratio (S/N > 10) medium-resolution (R = 2000) Large Binocular Telescope/LUCIFER spectrum of the early-type galaxy (ETG) S2F1-142 at z ≃ 1.4. By means of the CaT line at 8662 Å, we measured its redshift z = 1.386 ± 0.001 and we estimated its velocity dispersion σ v=340^{-60}_{+120} km s-1. Its corresponding virial mass is 3.9 × 1011 M⊙, compatible with the stellar mass estimates obtained assuming initial mass functions (IMFs) less dwarf rich than the Salpeter one. S2F1-142 is a compact galaxy with Re = 3.1 ± 0.2 kpc, i.e. an effective radius more than three times smaller than the average Re of ETGs with the same mass in the local Universe. At the same time, we found local and high-redshift galaxies with a similar mass content and similar effective radius confirming that it is fully consistent with the already available measures of Re and σv both in the local and in the distant Universe. Considering the distribution of Re and σv as a function of the stellar mass content of ETGs, both in the local and in the distant Universe, we noticed that the measured velocity dispersions of the more compact galaxies are on average slightly lower than expected on the basis of their compactness and the virial theorem, suggesting that (i) their dark matter content is lower than in the more diffuse galaxies and/or (ii) their luminosity profiles are steeper than in the more diffuse galaxies and/or (iii) their larger compactness is an apparent effect caused by the overestimate of their stellar mass content (due to bottom lighter IMF and/or systematic affecting the stellar mass estimates).

  14. Indirect Climatic Effects of Major Volcanic Eruptions

    Hofmann, D. J.

    2007-05-01

    The direct effects on climate, related to atmospheric emissions to the atmosphere following major volcanic eruptions, are well-known although the sparseness of such eruptions make detailed study on the range of such variations difficult. In general terms, infrared absorption by volcanic emissions to the stratosphere result in local heating early in the event when gaseous sulfur compounds exist. This early period is followed by gas to particle conversion, on a time scale of 1-2 months, promoting the formation of sulfuric acid-water droplets. Coagulation and droplet growth result in the "volcanic stratospheric aerosol layer" which is related to the predominant direct climatic effect of large eruptions, the cooling of the troposphere by backscattering of solar visible radiation to space with a recovery time scale of 1-2 years. In this paper we will discuss some of the less-known "indirect" effects of the volcanic stratospheric aerosol on climate. We label them indirect as they act on climate through intermediary atmospheric constituents. The intermediaries in the volcanic indirect climatic effect are generally atmospheric greenhouse gases or other atmospheric gases and conditions which affect greenhouse gases. For example, cooling of the troposphere following major eruptions reduces the growth rate of atmospheric carbon dioxide related to respiration by the terrestrial biosphere. In addition, redirection of part of the direct solar beam into diffuse radiation by the volcanic stratospheric aerosol stimulates plant photosynthesis, further reducing the carbon dioxide growth rate. The growth rate of the second-most important atmospheric greenhouse gas, methane, is also affected by volcanic emissions. Volcanic stratospheric aerosol particles provide surface area which catalyzes heterogeneous chemical reactions thus stimulating removal of stratospheric ozone, also a greenhouse gas. Although major droughts usually related to ENSO events have opposite effects on carbon

  15. Indirect effects in community ecology: Their definition, study and importance.

    Strauss, S Y

    1991-07-01

    The diversity of indirect interactions that can occur within communities is large. Recent research on indirect interactions is scattered in the literature under numerous labels. The definition of indirect effects is an important aspect of their study, and clarifies some of the subtle differences among indirect effects found in natural communities. Choosing which species to study, how to manipulate species and for what duration, which attributes to measure and, finally, which analytical techniques to use are all problems facing the community ecologist. Ultimately, we are striving for the best means of determining the relative importance of direct and indirect effects in structuring communities. Copyright © 1991. Published by Elsevier Ltd.

  16. Indirect evaporative coolers with enhanced heat transfer

    Kozubal, Eric; Woods, Jason; Judkoff, Ron

    2015-09-22

    A separator plate assembly for use in an indirect evaporative cooler (IEC) with an air-to-air heat exchanger. The assembly includes a separator plate with a first surface defining a dry channel and a second surface defining a wet channel. The assembly includes heat transfer enhancements provided on the first surface for increasing heat transfer rates. The heat transfer enhancements may include slit fins with bodies extending outward from the first surface of separator plate or may take other forms including vortex generators, offset strip fins, and wavy fins. In slit fin implementations, the separator plate has holes proximate to each of the slit fins, and the separator plate assembly may include a sealing layer applied to the second surface of the separator plate to block air flow through the holes. The sealing layer can be a thickness of adhesive, and a layer of wicking material is applied to the adhesive.

  17. Haloperidol Selectively Remodels Striatal Indirect Pathway Circuits

    Sebel, Luke E; Graves, Steven M; Chan, C Savio; Surmeier, D James

    2017-01-01

    Typical antipsychotic drugs are widely thought to alleviate the positive symptoms of schizophrenia by antagonizing dopamine D2 receptors expressed by striatal spiny projection neurons (SPNs). What is less clear is why antipsychotics have a therapeutic latency of weeks. Using a combination of physiological and anatomical approaches in ex vivo brain slices from transgenic mice, it was found that 2 weeks of haloperidol treatment induced both intrinsic and synaptic adaptations specifically within indirect pathway SPNs (iSPNs). Perphenazine treatment had similar effects. Some of these adaptations were homeostatic, including a drop in intrinsic excitability and pruning of excitatory corticostriatal glutamatergic synapses. However, haloperidol treatment also led to strengthening of a subset of excitatory corticostriatal synapses. This slow remodeling of corticostriatal iSPN circuitry is likely to play a role in mediating the delayed therapeutic action of neuroleptics. PMID:27577602

  18. Indirect Encoding in Neuroevolutionary Ship Handling

    Miroslaw Lacki

    2018-03-01

    Full Text Available In this paper the author compares the efficiency of two encoding schemes for artificial intelligence methods used in the neuroevolutionary ship maneuvering system. This may be also be seen as the ship handling system that simulates a learning process of a group of artificial helmsmen - autonomous control units, created with an artificial neural network. The helmsman observes input signals derived form an enfironment and calculates the values of required parameters of the vessel maneuvering in confined waters. In neuroevolution such units are treated as individuals in population of artificial neural networks, which through environmental sensing and evolutionary algorithms learn to perform given task efficiently. The main task of this project is to evolve a population of helmsmen with indirect encoding and compare results of simulation with direct encoding method.

  19. Indirect adaptive control of discrete chaotic systems

    Salarieh, Hassan; Shahrokhi, Mohammad

    2007-01-01

    In this paper an indirect adaptive control algorithm is proposed to stabilize the fixed points of discrete chaotic systems. It is assumed that the functionality of the chaotic dynamics is known but the system parameters are unknown. This assumption is usually applicable to many chaotic systems, such as the Henon map, logistic and many other nonlinear maps. Using the recursive-least squares technique, the system parameters are identified and based on the feedback linearization method an adaptive controller is designed for stabilizing the fixed points, or unstable periodic orbits of the chaotic maps. The stability of the proposed scheme has been shown and the effectiveness of the control algorithm has been demonstrated through computer simulations

  20. Indirect Tire Monitoring System - Machine Learning Approach

    Svensson, O.; Thelin, S.; Byttner, S.; Fan, Y.

    2017-10-01

    The heavy vehicle industry has today no requirement to provide a tire pressure monitoring system by law. This has created issues surrounding unknown tire pressure and thread depth during active service. There is also no standardization for these kind of systems which means that different manufacturers and third party solutions work after their own principles and it can be hard to know what works for a given vehicle type. The objective is to create an indirect tire monitoring system that can generalize a method that detect both incorrect tire pressure and thread depth for different type of vehicles within a fleet without the need for additional physical sensors or vehicle specific parameters. The existing sensors that are connected communicate through CAN and are interpreted by the Drivec Bridge hardware that exist in the fleet. By using supervised machine learning a classifier was created for each axle where the main focus was the front axle which had the most issues. The classifier will classify the vehicles tires condition and will be implemented in Drivecs cloud service where it will receive its data. The resulting classifier is a random forest implemented in Python. The result from the front axle with a data set consisting of 9767 samples of buses with correct tire condition and 1909 samples of buses with incorrect tire condition it has an accuracy of 90.54% (0.96%). The data sets are created from 34 unique measurements from buses between January and May 2017. This classifier has been exported and is used inside a Node.js module created for Drivecs cloud service which is the result of the whole implementation. The developed solution is called Indirect Tire Monitoring System (ITMS) and is seen as a process. This process will predict bad classes in the cloud which will lead to warnings. The warnings are defined as incidents. They contain only the information needed and the bandwidth of the incidents are also controlled so incidents are created within an

  1. Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer

    Defrere, D.; Hinz, P.; Downey, E.; Boehm, M.; Danchi, W. C.; Durney, O.; Ertel, S.; Hill, J. M.; Hoffmann, W. F.; Mennesson, B.; hide

    2016-01-01

    The Large Binocular Telescope Interferometer uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current performance of the system for dry air seeing compensation, we present simultaneous H-, K-, and N-band observations that illustrate the feasibility of our feed forward approach to stabilize the path length fluctuations seen by the LBTI nuller uses a near-infrared camera to measure the optical path length variations between the two AO-corrected apertures and provide high-angular resolution observations for all its science channels (1.5-13 microns). There is however a wavelength dependent component to the atmospheric turbulence, which can introduce optical path length errors when observing at a wavelength different from that of the fringe sensing camera. Water vapor in particular is highly dispersive and its effect must be taken into account for high-precision infrared interferometric observations as described previously for VLTI MIDI or the Keck Interferometer Nuller. In this paper, we describe the new sensing approach that has been developed at the LBT to measure and monitor the optical path length fluctuations due to dry air and water vapor separately. After reviewing the current

  2. Direct and indirect detection of supersymmetric dark matter; Detection directe et indirecte de matiere sombre supersymetrique

    Mayet, F

    2001-09-01

    A substantial body of astrophysical evidence supports the existence of non-baryonic dark matter in the universe. One of the leading dark matter candidates is the neutralino predicted by the supersymmetric extensions of the standard model of particle physics. Different detectors have been designed for the detection, either indirect or direct, of the neutralino. Related to indirect detection, the present work has been performed in the context of the AMS experiment. A precursor version of the spectrometer was flown on the space shuttle Discovery in June 1998. The detector included an Aerogel Threshold Cherenkov counter (ATC) to identify antiprotons, whose spectrum may be used to infer a neutralino signal. The analysis of the ATC data is presented including an evaluation of the flight performance and a description of the optimization of the antiproton selection. An antiproton analysis is also reported. A phenomenological study allows us to investigate the discovery potential of this indirect method. This thesis also includes the development of a new detector (MACHe3) designed for direct neutralino search using a superfluid {sup 3}He bolometer operated at ultra low temperatures. The data analysis of the prototype cell is presented. A Monte Carlo simulation has been developed, in order to optimize the detector design for direct neutralino search. These results are compared with theoretical predictions of supersymmetric models, thus highlighting the discovery potential of this detector and its complementarity with existing devices. (author)

  3. Performance comparison of direct and indirect lighting systems

    Rubinstein, F.; Morse, O.; Clark, T.

    1993-01-01

    The performance of a retrofitted indirect lighting system was compared to the performance of a typical de-lamped direct lighting system in a partitioned office space. Power, illuminance and luminance measurements were made for the de-lamped direct lighting system and after installation of the indirect lighting system with various lamp and ballast combinations. Using the same lamps and ballasts, average workplace illuminance was slightly higher with indirect lighting than with direct lighting. With indirect lighting, workplace lumen efficacy was 4.5% lower due to the higher power draw of the lamps in the more open and cooler indirect fixtures. Indirect lighting with 36 watt T-8 lamps and electronic ballasts achieved an initial average workplace illuminance of 45 foot-candles in the partitioned office space at only 1.1 w/ft 2

  4. Direct and indirect punishment among strangers in the field.

    Balafoutas, Loukas; Nikiforakis, Nikos; Rockenbach, Bettina

    2014-11-11

    Many interactions in modern human societies are among strangers. Explaining cooperation in such interactions is challenging. The two most prominent explanations critically depend on individuals' willingness to punish defectors: In models of direct punishment, individuals punish antisocial behavior at a personal cost, whereas in models of indirect reciprocity, they punish indirectly by withholding rewards. We investigate these competing explanations in a field experiment with real-life interactions among strangers. We find clear evidence of both direct and indirect punishment. Direct punishment is not rewarded by strangers and, in line with models of indirect reciprocity, is crowded out by indirect punishment opportunities. The existence of direct and indirect punishment in daily life indicates the importance of both means for understanding the evolution of cooperation.

  5. Indirect land use change and biofuel policy

    Kocoloski, Matthew; Griffin, W Michael; Matthews, H Scott

    2009-01-01

    Biofuel debates often focus heavily on carbon emissions, with parties arguing for (or against) biofuels solely on the basis of whether the greenhouse gas emissions of biofuels are less than (or greater than) those of gasoline. Recent studies argue that land use change leads to significant greenhouse gas emissions, making some biofuels more carbon intensive than gasoline. We argue that evaluating the suitability and utility of biofuels or any alternative energy source within the limited framework of plus and minus carbon emissions is too narrow an approach. Biofuels have numerous impacts, and policy makers should seek compromises rather than relying solely on carbon emissions to determine policy. Here, we estimate that cellulosic ethanol, despite having potentially higher life cycle CO 2 emissions (including from land use) than gasoline, would still be cost-effective at a CO 2 price of $80 per ton or less, well above estimated CO 2 mitigation costs for many alternatives. As an example of the broader approach to biofuel policy, we suggest the possibility of using the potential cost reductions of cellulosic ethanol relative to gasoline to balance out additional carbon emissions resulting from indirect land use change as an example of ways in which policies could be used to arrive at workable solutions.

  6. Spherical cows in dark matter indirect detection

    Bernal, Nicolás [Centro de Investigaciones, Universidad Antonio Nariño, Cra 3 Este # 47A-15, Bogotá (Colombia); Necib, Lina; Slatyer, Tracy R., E-mail: nicolas.bernal@uan.edu.co, E-mail: lnecib@mit.edu, E-mail: tslatyer@mit.edu [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2016-12-01

    Dark matter (DM) halos have long been known to be triaxial, but in studies of possible annihilation and decay signals they are often treated as approximately spherical. In this work, we examine the asymmetry of potential indirect detection signals of DM annihilation and decay, exploiting the large statistics of the hydrodynamic simulation Illustris. We carefully investigate the effects of the baryons on the sphericity of annihilation and decay signals for both the case where the observer is at 8.5 kpc from the center of the halo (exemplified in the case of Milky Way-like halos), and for an observer situated well outside the halo. In the case of Galactic signals, we find that both annihilation and decay signals are expected to be quite symmetric, with axis ratios very different from 1 occurring rarely. In the case of extragalactic signals, while decay signals are still preferentially spherical, the axis ratio for annihilation signals has a much flatter distribution, with elongated profiles appearing frequently. Many of these elongated profiles are due to large subhalos and/or recent mergers. Comparing to gamma-ray emission from the Milky Way and X-ray maps of clusters, we find that the gamma-ray background appears less spherical/more elongated than the expected DM signal from the large majority of halos, and the Galactic gamma ray excess appears very spherical, while the X-ray data would be difficult to distinguish from a DM signal by elongation/sphericity measurements alone.

  7. Indirectly cooled large thin superconducting CDF solenoid

    Kondo, Kunitaka; Mori, Shigeki; Yoshizaki, Ryozo; Saito, Ryusei; Asano, Katsuhiko.

    1985-01-01

    The manufacturing technique of the indirectly cooled large thin superconducting solenoid for the collider detector facility (CDF solenoid) has been studied through cooperation of University of Tsukuba and the National Laboratory for High Energy Physics of the Ministry of Education of Japan, and the Fermi National Accelerator Laboratory in the U.S. Fabrication and testing of the solenoid has recently been completed by Hitachi. The CDF solenoid has a large-sized thin structure for meeting the requirement by experiments to be applied. Hitachi has thus developed a variety of new technologies including the design standard, coil cooling method, material selection, and manufacturing technique in accordance with experimental data, which were confirmed in a series of analyses and tests made on various prototypes. The CDF solenoid, built using Hitachi's new technologies, is of the world's top class among equipment of this type. This paper outlines the design criteria for the major components employed in the CDF solenoid and the test results of the solenoid. (author)

  8. An Automatic Indirect Immunofluorescence Cell Segmentation System

    Yung-Kuan Chan

    2014-01-01

    Full Text Available Indirect immunofluorescence (IIF with HEp-2 cells has been used for the detection of antinuclear autoantibodies (ANA in systemic autoimmune diseases. The ANA testing allows us to scan a broad range of autoantibody entities and to describe them by distinct fluorescence patterns. Automatic inspection for fluorescence patterns in an IIF image can assist physicians, without relevant experience, in making correct diagnosis. How to segment the cells from an IIF image is essential in developing an automatic inspection system for ANA testing. This paper focuses on the cell detection and segmentation; an efficient method is proposed for automatically detecting the cells with fluorescence pattern in an IIF image. Cell culture is a process in which cells grow under control. Cell counting technology plays an important role in measuring the cell density in a culture tank. Moreover, assessing medium suitability, determining population doubling times, and monitoring cell growth in cultures all require a means of quantifying cell population. The proposed method also can be used to count the cells from an image taken under a fluorescence microscope.

  9. INDIRECT WRITTEN CORRECTIVE FEEDBACK, REVISION, AND LEARNING

    Fatemeh Poorebrahim

    2017-01-01

    Full Text Available Corrective feedback, the necessity of providing it, and how it should be provided has been one of the hot topics in the area of ELT. Amid continuing controversies over whether providing feedback helps L2 learners improve their writing accuracy, many research studies have been undertaken to compare the relative effectiveness of different types of feedback. However, the difference between two types of indirect corrective feedback, namely indication and indication plus location, have not been properly examined yet. Motivated to narrow this gap, this study is designed to compare two groups of Iranian learners, each revising their papers based on one of the aforementioned options. For data analysis, a series of independent samples t tests were employed. The results revealed that the difference between the two groups in their reduction of errors from the original draft to the revision of each task followed a growing trend and became significant. Nonetheless, the difference in accuracy of new pieces of writing fell short of significance. Finally, it was found that error reduction in revision stage cannot be considered as learning. The results of the study, discussed in relation to that of others, implicate that the purpose for which feedback is provided is essential in determining the type of feedback; more explicit feedback is better for revising purposes while more implicit feedback is good for learning purposes.

  10. Indirect Sensitivities to the Scale of Supersymmetry

    Ellis, Jonathan Richard; Olive, Keith A; Weiglein, Georg

    2005-01-01

    Precision measurements, now and at a future linear electron-positron collider (ILC), can provide indirect information about the possible scale of supersymmetry. We illustrate the present-day and possible future ILC sensitivities within the constrained minimal supersymmetric extension of the Standard Model (CMSSM), in which there are three independent soft supersymmetry-breaking parameters m_{1/2}, m_0 and A_0. We analyze the present and future sensitivities separately for M_W, sin^2(theta_eff), (g-2)_mu, BR(b -> s gamma), BR(B_s -> mu+ mu-), M_h and Higgs branching ratios. We display the observables as functions of m_{1/2}, fixing m_0 so as to obtain the cold dark matter density allowed by WMAP and other cosmological data for specific values of A_0, tan beta and mu > 0. In a second step, we investigate the combined sensitivity of the currently available precision observables, M_W, sin^2(theta_eff), (g-2)_mu and BR(b -> s gamma), by performing a chi^2 analysis. The current data are in very good agreement with ...

  11. Theoretical research on color indirect effects

    Liu, T. C.; Liao, Changjun; Liu, Songhao

    1995-05-01

    Color indirect effects (CIE) means the physiological and psychological effects of color resulting from color vision. In this paper, we study CIE from the viewpoints of the integrated western and Chinese traditional medicine and the time quantum theory established by C. Y. Liu et al., respectively, and then put forward the color-automatic-nervous-subsystem model that could color excites parasympathetic subsystem and hot color excites sympathetic subsystem. Our theory is in agreement with modern color vision theory, and moreover, it leads to the resolution of the conflict between the color code theory and the time code theory oncolor vision. For the latitude phenomena on athlete stars number and the average lifespan, we also discuss the possibility of UV vision. The applications of our theory lead to our succeeding in explaining a number of physiological and psychological effects of color, in explaining the effects of age on color vision, and in explaining the Chinese chromophototherapy. We also discuss its application to neuroimmunology. This research provides the foundation of the clinical applications of chromophototherapy.

  12. Decentralized indirect methods for learning automata games.

    Tilak, Omkar; Martin, Ryan; Mukhopadhyay, Snehasis

    2011-10-01

    We discuss the application of indirect learning methods in zero-sum and identical payoff learning automata games. We propose a novel decentralized version of the well-known pursuit learning algorithm. Such a decentralized algorithm has significant computational advantages over its centralized counterpart. The theoretical study of such a decentralized algorithm requires the analysis to be carried out in a nonstationary environment. We use a novel bootstrapping argument to prove the convergence of the algorithm. To our knowledge, this is the first time that such analysis has been carried out for zero-sum and identical payoff games. Extensive simulation studies are reported, which demonstrate the proposed algorithm's fast and accurate convergence in a variety of game scenarios. We also introduce the framework of partial communication in the context of identical payoff games of learning automata. In such games, the automata may not communicate with each other or may communicate selectively. This comprehensive framework has the capability to model both centralized and decentralized games discussed in this paper.

  13. Indirect land use change and biofuel policy

    Kocoloski, Matthew; Griffin, W. Michael; Matthews, H. Scott

    2009-09-01

    Biofuel debates often focus heavily on carbon emissions, with parties arguing for (or against) biofuels solely on the basis of whether the greenhouse gas emissions of biofuels are less than (or greater than) those of gasoline. Recent studies argue that land use change leads to significant greenhouse gas emissions, making some biofuels more carbon intensive than gasoline. We argue that evaluating the suitability and utility of biofuels or any alternative energy source within the limited framework of plus and minus carbon emissions is too narrow an approach. Biofuels have numerous impacts, and policy makers should seek compromises rather than relying solely on carbon emissions to determine policy. Here, we estimate that cellulosic ethanol, despite having potentially higher life cycle CO2 emissions (including from land use) than gasoline, would still be cost-effective at a CO2 price of 80 per ton or less, well above estimated CO2 mitigation costs for many alternatives. As an example of the broader approach to biofuel policy, we suggest the possibility of using the potential cost reductions of cellulosic ethanol relative to gasoline to balance out additional carbon emissions resulting from indirect land use change as an example of ways in which policies could be used to arrive at workable solutions.

  14. Noninvasive wearable sensor for indirect glucometry.

    Zilberstein, Gleb; Zilberstein, Roman; Maor, Uriel; Righetti, Pier Giorgio

    2018-04-02

    A noninvasive mini-sensor for blood glucose concentration assessment has been developed. The monitoring is performed by gently pressing a wrist or fingertip onto the chemochromic mixture coating a thin glass or polymer film positioned on the back panel of a smart watch with PPG/HRM (photoplethysmographic/heart rate monitoring sensor). The various chemochromic components measure the absolute values of the following metabolites present in the sweat: acetone, acetone beta-hydroxybutirate, aceto acetate, water, carbon dioxide, lactate anion, pyruvic acid, Na and K salts. Taken together, all these parameters give information about blood glucose concentration, calculated via multivariate analysis based on neural network algorithms built into the sensor. The Clarke Error Grid shows an excellent correlation between data measured by the standard invasive glucose analyser and the present noninvasive sensor, with all points aligned along a 45-degree diagonal and contained almost exclusively in sector A. Graphs measuring glucose levels five times a day (prior, during and after breakfast and prior, during and after lunch), for different individuals (males and females) show a good correlation between the two curves of conventional, invasive meters vs. the noninvasive sensor, with an error of ±15%. This novel, noninvasive sensor for indirect glucometry is fully miniaturized, easy to use and operate and could represent a valid alternative in clinical settings and for individual, personal users, to current, invasive tools. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Bioelectrochemical Systems for Indirect Biohydrogen Production

    Regan, John M.

    2014-01-01

    Bioelectrochemical systems involve the use of exoelectrogenic (i.e., anode-reducing) microbes to produce current in conjunction with the oxidation of reduced compounds. This current can be used directly for power in a microbial fuel cell, but there are alternate uses of this current. One such alternative is the production of hydrogen in a microbial electrolysis cell (MEC), which accomplishes cathodic proton reduction with a slight applied potential by exploiting the low redox potential produced by exoelectrogens at the anode. As an indirect approach to biohydrogen production, these systems are not subject to the hydrogen yield constraints of fermentative processes and have been proven to work with virtually any biodegradable organic substrate. With continued advancements in reactor design to reduce the system internal resistance, increase the specific surface area for anode biofilm development, and decrease the material costs, MECs may emerge as a viable alternative technology for biohydrogen production. Moreover, these systems can also incorporate other value-added functionalities for applications in waste treatment, desalination, and bioremediation.

  16. Health-related quality of life and binocular vision in patients with diplopia in acute-onset comitant esotropia with press-on prism improves

    Qian Wang

    2017-11-01

    Full Text Available AIM: To assess the effect of press-on prisms in patients with acute-onset comitant esotropia and diplopia, focusing primarily on vision-related quality of life and binocular vision. METHODS: Retrospective case-series study. Totally 16 acute-onset comitant esotropia patients with diplopia who received treatment in the Huzhou Central Hospital were included in this study from March 2014 to March 2017. Vision-related quality of life before press-on prism correction and 1mo after press-on prism correction were performed with the Chinese version of the 25-item National Eye Institute Visual Functioning Questionnaire(CHI-NEI-VFQ-25. In each time of follow-up, we made a minute examination, includes worth four dot test and stereo tests. Data was statistically analyzed with paired sample t test, Chi-square test and Fisher's exact test. RESULTS: Except the degree of eye pain, color vision and perimetry, the indicators from CHI-NEI-VFQ-25 table including general health status, overall vision, mental health, social role difficulties, social functional, near activities, distant activities, independency and driving of acute-onset comitant esotropia patients with diplopia were obviously significant improved 1mo after press-on prism correction(PPCONCLUSION: Press-on prism correction may be helpful for binocular vision recovery in acute-onset comitant esotropia patients with diplopia, so as improve the vision-related quality of life.

  17. Preliminary results from the use of the novel Interactive binocular treatment (I-BiT) system, in the treatment of strabismic and anisometropic amblyopia.

    Waddingham, P E; Butler, T K H; Cobb, S V; Moody, A D R; Comaish, I F; Haworth, S M; Gregson, R M; Ash, I M; Brown, S M; Eastgate, R M; Griffiths, G D

    2006-03-01

    We have developed a novel application of adapted virtual reality (VR) technology, for the binocular treatment of amblyopia. We describe the use of the system in six children. Subjects consisted of three conventional treatment 'failures' and three conventional treatment 'refusers', with a mean age of 6.25 years (5.42-7.75 years). Treatment consisted of watching video clips and playing interactive games with specifically designed software to allow streamed binocular image presentation. Initial vision in the amblyopic eye ranged from 6/12 to 6/120 and post-treatment 6/7.5 to 6/24-1. Total treatment time was a mean of 4.4 h. Five out of six children have shown an improvement in their vision (average increase of 10 letters), including those who had previously failed to comply with conventional occlusion. Improvements in vision were demonstrable within a short period of time, in some children after 1 h of treatment. This system is an exciting and promising application of VR technology as a new treatment for amblyopia.

  18. System markets: Indirect network effects in action, or inaction?

    Binken, Jeroen

    2010-01-01

    textabstractIn this dissertation, I empirically examine system markets up close. More specifically I examine indirect network effects, both demand-side and supply-side indirect network effects. Indirect network effects are the source of positive feedback in system markets, or so network effect theory tells us. Systems are composed of complementary and interdependent products, such as hardware and software. For instance, a video game system is composed of the video game console, on the one han...

  19. Indirect detection methods: Looking for what is not there

    Yeung, E.S.

    1989-01-01

    Indirect detection allows one to monitor species that normally do not give a response. It has grown from an intellectual curiosity to become an extremely useful tool. For volume displacement, polarimetry gives the best results. For charge displacement, ion chromatography and capillary zone electrophoresis are ideal situations for applying indirect fluorescence detection. LOD surpasses all but the most specialized detection schemes. Future developments in systems specially designed for indirect detection should make these schemes even more powerful

  20. Indirect Catastrophic Injuries in Olympic Styles of Wrestling in Iran

    Kordi, Ramin; Ziaee, Vahid; Rostami, Mohsen; Wallace, W. Angus

    2011-01-01

    Background: Data on indirect catastrophic injuries in wrestling are scarce. Objectives: To develop a profile of indirect catastrophic injuries in international styles of wrestling and to describe possible risk factors. Study Design: Retrospective case series; Level of evidence, 3. Methods: Indirect catastrophic injuries that occurred in wrestling clubs in Iran from July 1998 to June 2005 were identified by contacting several sources. The cases were retrospectively reviewed. Results: The injur...

  1. Tipping and Concentration in Markets with Indirect Network Effects

    Jean-Pierre H. Dubé; Günter J. Hitsch; Pradeep K. Chintagunta

    2010-01-01

    This paper develops a framework for measuring “tipping”—the increase in a firm's market share dominance caused by indirect network effects. Our measure compares the expected concentration in a market to the hypothetical expected concentration that would arise in the absence of indirect network effects. In practice, this measure requires a model that can predict the counterfactual market concentration under different parameter values capturing the strength of indirect network effects. We build...

  2. Effectiveness of a Binocular Video Game vs Placebo Video Game for Improving Visual Functions in Older Children, Teenagers, and Adults With Amblyopia: A Randomized Clinical Trial.

    Gao, Tina Y; Guo, Cindy X; Babu, Raiju J; Black, Joanna M; Bobier, William R; Chakraborty, Arijit; Dai, Shuan; Hess, Robert F; Jenkins, Michelle; Jiang, Yannan; Kearns, Lisa S; Kowal, Lionel; Lam, Carly S Y; Pang, Peter C K; Parag, Varsha; Pieri, Roberto; Raveendren, Rajkumar Nallour; South, Jayshree; Staffieri, Sandra Elfride; Wadham, Angela; Walker, Natalie; Thompson, Benjamin

    2018-02-01

    Binocular amblyopia treatment using contrast-rebalanced stimuli showed promise in laboratory studies and requires clinical trial investigation in a home-based setting. To compare the effectiveness of a binocular video game with a placebo video game for improving visual functions in older children and adults. The Binocular Treatment of Amblyopia Using Videogames clinical trial was a multicenter, double-masked, randomized clinical trial. Between March 2014 and June 2016, 115 participants 7 years and older with unilateral amblyopia (amblyopic eye visual acuity, 0.30-1.00 logMAR; Snellen equivalent, 20/40-20/200) due to anisometropia, strabismus, or both were recruited. Eligible participants were allocated with equal chance to receive either the active or the placebo video game, with minimization stratified by age group (child, age 7 to 12 years; teenager, age 13 to 17 years; and adult, 18 years and older). Falling-blocks video games played at home on an iPod Touch for 1 hour per day for 6 weeks. The active video game had game elements split between eyes with a dichoptic contrast offset (mean [SD] initial fellow eye contrast, 0.23 [0.14]). The placebo video game presented identical images to both eyes. Change in amblyopic eye visual acuity at 6 weeks. Secondary outcomes included compliance, stereoacuity, and interocular suppression. Participants and clinicians who measured outcomes were masked to treatment allocation. Of the 115 included participants, 65 (56.5%) were male and 83 (72.2%) were white, and the mean (SD) age at randomization was 21.5 (13.6) years. There were 89 participants (77.4%) who had prior occlusion. The mean (SD) amblyopic eye visual acuity improved 0.06 (0.12) logMAR from baseline in the active group (n = 56) and 0.07 (0.10) logMAR in the placebo group (n = 59). The mean treatment difference between groups, adjusted for baseline visual acuity and age group, was -0.02 logMAR (95% CI, -0.06 to 0.02; P = .25). Compliance with more than 25

  3. Amblyopia and Binocular Vision

    Birch, Eileen E.

    2012-01-01

    Amblyopia is the most common cause of monocular visual loss in children, affecting 1.3% to 3.6% of children. Current treatments are effective in reducing the visual acuity deficit but many amblyopic individuals are left with residual visual acuity deficits, ocular motor abnormalities, deficient fine motor skills, and risk for recurrent amblyopia. Using a combination of psychophysical, electrophysiological, imaging, risk factor analysis, and fine motor skill assessment, the primary role of bin...

  4. Indirect estimation of radioactivity in containerized cargo

    Jarman, K.D.; Scherrer, C.; Smith, L.E.; Chilton, L.K.; Anderson, K.K.; Ressler, J.J.; Trease, L.L.

    2011-01-01

    Naturally occurring radioactive material in containerized cargo challenges the state of the art in national and international efforts to detect illicit nuclear and radiological material in transported containers. Current systems are being evaluated and new systems envisioned to provide the high probability of detection necessary to thwart potential threats, combined with extremely low nuisance and false alarm rates necessary to maintain the flow of commerce impacted by the enormous volume of commodities imported in shipping containers. Maintaining flow of commerce also means that inspection must be rapid, requiring relatively non-intrusive, indirect measurements of cargo from outside containers to the extent possible. With increasing information content in such measurements, it is natural to ask how the information might be combined to improve detection. Toward this end, we present an approach to estimating isotopic activity of naturally occurring radioactive material in cargo grouped by commodity type, combining container manifest data with radiography and gamma-ray spectroscopy aligned to location along the container. The heart of this approach is our statistical model of gamma-ray counts within peak regions of interest, which captures the effects of background suppression, counting noise, convolution of neighboring cargo contributions, and down-scattered photons to provide estimates of counts due to decay of specific radioisotopes in cargo alone. Coupled to that model, we use a mechanistic model of self-attenuated radiation flux to estimate the isotopic activity within cargo, segmented by location within each container, that produces those counts. We test our approach by applying it to a set of measurements taken at the Port of Seattle in 2006. This approach to synthesizing disparate available data streams and extraction of cargo characteristics, while relying on several simplifying assumptions and approximations, holds the potential to support improvement of

  5. 42 CFR 412.322 - Indirect medical education adjustment factor.

    2010-10-01

    ... Payment System for Inpatient Hospital Capital Costs Basic Methodology for Determining the Federal Rate for Capital-Related Costs § 412.322 Indirect medical education adjustment factor. (a) Basic data. CMS.... The indirect teaching adjustment factor equals [e (raised to the power of .2822×the ratio of residents...

  6. A Computational Approach to the Interpretation of Indirect Speech Acts

    Beun, R.J.; Eijk, R.M. van; Meyer, J-J.Ch.; Vergunst, N.L.

    2006-01-01

    An Indirect Speech Act (ISA) is an utterance that conveys a message that is different from its literal meaning, often for reasons of politeness or subtlety. The DenK-system provides us with a non-compositional way to look at Indirect Speech Acts that contain modal verbs. We can extract the

  7. Indirect Positive Evidence in the Acquisition of a Subset Grammar

    Schwartz, Misha; Goad, Heather

    2017-01-01

    This article proposes that second language learners can use indirect positive evidence (IPE) to acquire a phonological grammar that is a subset of their L1 grammar. IPE is evidence from errors in the learner's L1 made by native speakers of the learner's L2. It has been assumed that subset grammars may be acquired using direct or indirect negative…

  8. The Adoption of Indirect Instruments of Monetary Policy

    Tomás J. T. Baliño; Charles Enoch; William E. Alexander

    1995-01-01

    This paper examines the experience of implementing indirect instruments of monetary policy. The experiences of country studies illustrate the variety of circumstances under which indirect instruments of monetary policy have been introduced. Case Studies are presented for Chile, Egypt, Ghana, Indonesia, Mexico, New Zealand, and Poland.

  9. The Influence of Direct and Indirect Speech on Source Memory

    Anita Eerland

    2018-02-01

    Full Text Available People perceive the same situation described in direct speech (e.g., John said, “I like the food at this restaurant” as more vivid and perceptually engaging than described in indirect speech (e.g., John said that he likes the food at the restaurant. So, if direct speech enhances the perception of vividness relative to indirect speech, what are the effects of using indirect speech? In four experiments, we examined whether the use of direct and indirect speech influences the comprehender’s memory for the identity of the speaker. Participants read a direct or an indirect speech version of a story and then addressed statements to one of the four protagonists of the story in a memory task. We found better source memory at the level of protagonist gender after indirect than direct speech (Exp. 1–3. When the story was rewritten to make the protagonists more distinctive, we also found an effect of speech type on source memory at the level of the individual, with better memory after indirect than direct speech (Exp. 3–4. Memory for the content of the story, however, was not influenced by speech type (Exp. 4. While previous research showed that direct speech may enhance memory for how something was said, we conclude that indirect speech enhances memory for who said what.

  10. 10 CFR 602.15 - Indirect cost limitations.

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Indirect cost limitations. 602.15 Section 602.15 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS EPIDEMIOLOGY AND OTHER HEALTH STUDIES FINANCIAL ASSISTANCE PROGRAM § 602.15 Indirect cost limitations. Awards issued under this part for conferences and...

  11. 10 CFR 605.16 - Indirect cost limitations.

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Indirect cost limitations. 605.16 Section 605.16 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS THE OFFICE OF ENERGY RESEARCH FINANCIAL ASSISTANCE PROGRAM § 605.16 Indirect cost limitations. Awards issued under this part for conferences and scientific...

  12. The indirect radioiodination of vasoactive intestinal peptide

    Wang Lihua; Li Junling; Yin Duanzhi; Zhang Lei; Zhang Xiuli; Wang Yongxian

    2002-01-01

    Objective: To seek for an effective way to acquire radiolabeled vasoactive intestinal peptide (VIP) with excellent in vivo stability. N-succinimidyl-3-iodo-125-benzoate (S 125 IB) came from radioiodination of N-succinimidyl-3-(tri-n-butylstannyl) benzoate (ATE) precursor and then conjugated with VIP to form 125 IBA-VIP. The labelling procedure was optimized; the in vitro stability and biological activity were evaluated. Methods: 1) Radiolabeling of ATE precursor was achieved with iodogen oxidant and the influential factors were considered in this procedure. The labeling efficiency was determined by thin layer chromatography (TLC) and the purification was carried out by Sep-pak silica gel cartridge. The stability was detected by TLC after 2 h storage in dark at 4 degree C. 2) Conjugation of S 125 IB and VIP. The labelling efficiency was determined with RP TLC and the purification was carried out with high performance liquid chromatography (HPLC, RP C18 column). Trichloroacetic acid (TCA) precipitation method was applied to evaluate the in vitro stability while the biological activity was determined by cell binding experiments with SGC7901 cell lines. Results: 1) S 125 IB experiments. The radioiodination of ATE was performed well for 5 min at 25 degree C with 10 micrograms of iodogen at suitable mole ratio (3-8:1) of ATE/Na 125 I, the labelling efficiency was about 96%. The stability was kept well at 4 degree C in dark, no significant decrease of S 125 IB was observed. 2) The conjugation efficiency of S 125 IB and VIP was above 75% with TLC. HPLC showed the different retention time (t R ) as follows, 125 IBA-VIP: 13.3 min, S 125 IB: 19.6 min, VIP: 8.32 min. The stability of 125 IBA-VIP was better than 125 I-VIP from direct radioiodination of VIP with iodogen oxidant, only 2.85% decrease was found after 7 d at 4 degree C. The biological activity of 125 IBA-VIP was kept as well as 125 I-VIP under the condition of 37 degree C 60 min. Conclusions: The indirect

  13. Indirect Control for Demand Side Management – A Conceptual Introduction

    Heussen, Kai; You, Shi; Biegel, Benjamin

    2012-01-01

    The concept of “indirect control” has become a relevant discussion term in relation to activation distributed and small-scale demand and generation units to provide resources for power system balancing. The term and its association with price signals has, however caused some confusion as to its...... correct definition, either as a control or a market concept. This paper aims to provide a conceptual introduction to "indirect control" for management of small and distributed demand side resources. A review of control concepts and an analysis of "indirectness" features are provided to create a framework...... for systematic classification of indirect control strategies. The concepts developed then enable a discussion of control performance and valuation of direct- and indirect control strategies....

  14. Smoking Cessation Is Associated With Lower Indirect Costs.

    Baker, Christine L; Bruno, Marianna; Emir, Birol; Li, Vicky W; Goren, Amir

    2018-06-01

    This study quantified differences in indirect costs due to decreased work productivity between current and former smokers. Former smokers were further categorized by number of years since quitting to assess corresponding differences. Data on employed individuals were obtained from the 2013 US National Health and Wellness Survey (NHWS; N = 75,000). Indirect costs were calculated for current smokers and former smokers from weekly wages based on age and sex. The annual total indirect costs for current smokers were $1327.53, $1560.18, and $1839.87 higher than for those who quit 0 to 4 years, 5 to 10 years, and more than or equal to 11 years prior, respectively. There were no significant differences in mean total indirect costs between the former smoker groups. Current smokers showed significantly higher total annual indirect costs compared with former smokers, independently of the number of years since quitting smoking.

  15. Forecasting of indirect consumables for a Job Shop

    Shakeel, M.; Khan, S.; Khan, W. A.

    2016-08-01

    A job shop has an arrangement where similar machines (Direct consumables) are grouped together and use indirect consumables to produce a product. The indirect consumables include hack saw blades, emery paper, painting brush etc. The job shop is serving various orders at a particular time for the optimal operation of job shop. Forecasting is required to predict the demand of direct and indirect consumables in a job shop. Forecasting is also needed to manage lead time, optimize inventory cost and stock outs. The objective of this research is to obtain the forecast for indirect consumables. The paper shows how job shop can manage their indirect consumables more accurately by establishing a new technique of forecasting. This results in profitable use of job shop by multiple users.

  16. An indecent proposal: the dual functions of indirect speech.

    Chakroff, Aleksandr; Thomas, Kyle A; Haque, Omar S; Young, Liane

    2015-01-01

    People often use indirect speech, for example, when trying to bribe a police officer by asking whether there might be "a way to take care of things without all the paperwork." Recent game theoretic accounts suggest that a speaker uses indirect speech to reduce public accountability for socially risky behaviors. The present studies examine a secondary function of indirect speech use: increasing the perceived moral permissibility of an action. Participants report that indirect speech is associated with reduced accountability for unethical behavior, as well as increased moral permissibility and increased likelihood of unethical behavior. Importantly, moral permissibility was a stronger mediator of the effect of indirect speech on likelihood of action, for judgments of one's own versus others' unethical action. In sum, the motorist who bribes the police officer with winks and nudges may not only avoid public punishment but also maintain the sense that his actions are morally permissible. Copyright © 2014 Cognitive Science Society, Inc.

  17. Driving with binocular visual field loss? A study on a supervised on-road parcours with simultaneous eye and head tracking.

    Enkelejda Kasneci

    Full Text Available Post-chiasmal visual pathway lesions and glaucomatous optic neuropathy cause binocular visual field defects (VFDs that may critically interfere with quality of life and driving licensure. The aims of this study were (i to assess the on-road driving performance of patients suffering from binocular visual field loss using a dual-brake vehicle, and (ii to investigate the related compensatory mechanisms. A driving instructor, blinded to the participants' diagnosis, rated the driving performance (passed/failed of ten patients with homonymous visual field defects (HP, including four patients with right (HR and six patients with left homonymous visual field defects (HL, ten glaucoma patients (GP, and twenty age and gender-related ophthalmologically healthy control subjects (C during a 40-minute driving task on a pre-specified public on-road parcours. In order to investigate the subjects' visual exploration ability, eye movements were recorded by means of a mobile eye tracker. Two additional cameras were used to monitor the driving scene and record head and shoulder movements. Thus this study is novel as a quantitative assessment of eye movements and an additional evaluation of head and shoulder was performed. Six out of ten HP and four out of ten GP were rated as fit to drive by the driving instructor, despite their binocular visual field loss. Three out of 20 control subjects failed the on-road assessment. The extent of the visual field defect was of minor importance with regard to the driving performance. The site of the homonymous visual field defect (HVFD critically interfered with the driving ability: all failed HP subjects suffered from left homonymous visual field loss (HL due to right hemispheric lesions. Patients who failed the driving assessment had mainly difficulties with lane keeping and gap judgment ability. Patients who passed the test displayed different exploration patterns than those who failed. Patients who passed focused longer on

  18. Effect of pictorial depth cues, binocular disparity cues and motion parallax depth cues on lightness perception in three-dimensional virtual scenes.

    Michiteru Kitazaki

    2008-09-01

    Full Text Available Surface lightness perception is affected by scene interpretation. There is some experimental evidence that perceived lightness under bi-ocular viewing conditions is different from perceived lightness in actual scenes but there are also reports that viewing conditions have little or no effect on perceived color. We investigated how mixes of depth cues affect perception of lightness in three-dimensional rendered scenes containing strong gradients of illumination in depth.Observers viewed a virtual room (4 m width x 5 m height x 17.5 m depth with checkerboard walls and floor. In four conditions, the room was presented with or without binocular disparity (BD depth cues and with or without motion parallax (MP depth cues. In all conditions, observers were asked to adjust the luminance of a comparison surface to match the lightness of test surfaces placed at seven different depths (8.5-17.5 m in the scene. We estimated lightness versus depth profiles in all four depth cue conditions. Even when observers had only pictorial depth cues (no MP, no BD, they partially but significantly discounted the illumination gradient in judging lightness. Adding either MP or BD led to significantly greater discounting and both cues together produced the greatest discounting. The effects of MP and BD were approximately additive. BD had greater influence at near distances than far.These results suggest the surface lightness perception is modulated by three-dimensional perception/interpretation using pictorial, binocular-disparity, and motion-parallax cues additively. We propose a two-stage (2D and 3D processing model for lightness perception.

  19. An improved recommendation algorithm via weakening indirect linkage effect

    Chen Guang; Qiu Tian; Shen Xiao-Quan

    2015-01-01

    We propose an indirect-link-weakened mass diffusion method (IMD), by considering the indirect linkage and the source object heterogeneity effect in the mass diffusion (MD) recommendation method. Experimental results on the MovieLens, Netflix, and RYM datasets show that, the IMD method greatly improves both the recommendation accuracy and diversity, compared with a heterogeneity-weakened MD method (HMD), which only considers the source object heterogeneity. Moreover, the recommendation accuracy of the cold objects is also better elevated in the IMD than the HMD method. It suggests that eliminating the redundancy induced by the indirect linkages could have a prominent effect on the recommendation efficiency in the MD method. (paper)

  20. Types of suggestibility: Relationships among compliance, indirect, and direct suggestibility.

    Polczyk, Romuald; Pasek, Tomasz

    2006-10-01

    It is commonly believed that direct suggestibility, referring to overt influence, and indirect suggestibility, in which the intention to influence is hidden, correlate poorly. This study demonstrates that they are substantially related, provided that they tap similar areas of influence. Test results from 103 students, 55 women and 48 men, were entered into regression analyses. Indirect suggestibility, as measured by the Sensory Suggestibility Scale for Groups, and compliance, measured by the Gudjonsson Compliance Scale, were predictors of direct suggestibility, assessed with the Barber Suggestibility Scale. Spectral analyses showed that indirect suggestibility is more related to difficult tasks on the BSS, but compliance is more related to easy tasks on this scale.

  1. Indirect Taxes in Romania – an Econometric Analysis

    Daniela Penu

    2016-03-01

    Full Text Available Indirect taxes have a significant weight in the GDP. Statistical data reveals that the new states that joined the EU in its funding sources to the greatest extent through indirect taxes. They reveal, on the one hand, reducing the tax burden on the producer, and on the other hand, the difficulty faced by the country in direct tax collection, but also some problems of social nature. This article proposes an econometric analysis of the relationship between indirect taxes and household final consumption expenditure.

  2. Indirect Genetic Effects for group-housed animals

    Alemu, Setegn Worku

    This thesis investigated social interactions in group-housed animals. The main findings of this thesis: 1) Statistical methods to estimate indirect genetic effects when interactions differ between kin vs. non-kin were developed. 2) Indirect genetic effects contribute a substantial amount...... of heritable variation for bite mark traits in group-housed min. 3) Indirect genetic effects estimation needs to take into account systematic interactions due to sex or kin for bite mark trait in group-housed min. 4) Genomic selection can be used to increase the response to selection for survival time in Brown...

  3. Indirect Inference for Stochastic Differential Equations Based on Moment Expansions

    Ballesio, Marco; Tempone, Raul; Vilanova, Pedro

    2016-01-01

    We provide an indirect inference method to estimate the parameters of timehomogeneous scalar diffusion and jump diffusion processes. We obtain a system of ODEs that approximate the time evolution of the first two moments of the process

  4. An Indirect Assessment of the War Against Iraq

    Ferguson Jr, C. M

    1992-01-01

    ...? General Schwartzkopf's statement of intent reveals that his strategy for the conduct of operations reflected an appreciation for the "indirect approach," of Sun Tzu and his erstwhile protege, B. H. Liddell-Hart...

  5. Separating astrophysical sources from indirect dark matter signals

    Siegal-Gaskins, Jennifer M.

    2015-01-01

    Indirect searches for products of dark matter annihilation and decay face the challenge of identifying an uncertain and subdominant signal in the presence of uncertain backgrounds. Two valuable approaches to this problem are (i) using analysis methods which take advantage of different features in the energy spectrum and angular distribution of the signal and backgrounds and (ii) more accurately characterizing backgrounds, which allows for more robust identification of possible signals. These two approaches are complementary and can be significantly strengthened when used together. I review the status of indirect searches with gamma rays using two promising targets, the Inner Galaxy and the isotropic gamma-ray background. For both targets, uncertainties in the properties of backgrounds are a major limitation to the sensitivity of indirect searches. I then highlight approaches which can enhance the sensitivity of indirect searches using these targets. PMID:25304638

  6. Indirect Monetary Policy Reforms and Output Growth in Nigeria: An ...

    BRRE). The efforts in repositioning these banks through the current banking reforms (recapitalization and consolidation) the paper notes are a right step in the right direction. Keywords: Indirect monetary policy, Granger – causality, output growth

  7. Indirect inference with time series observed with error

    Rossi, Eduardo; Santucci de Magistris, Paolo

    estimation. We propose to solve this inconsistency by jointly estimating the nuisance and the structural parameters. Under standard assumptions, this estimator is consistent and asymptotically normal. A condition for the identification of ARMA plus noise is obtained. The proposed methodology is used......We analyze the properties of the indirect inference estimator when the observed series are contaminated by measurement error. We show that the indirect inference estimates are asymptotically biased when the nuisance parameters of the measurement error distribution are neglected in the indirect...... to estimate the parameters of continuous-time stochastic volatility models with auxiliary specifications based on realized volatility measures. Monte Carlo simulations shows the bias reduction of the indirect estimates obtained when the microstructure noise is explicitly modeled. Finally, an empirical...

  8. RESEMBLANCE OF INDIRECTNESS IN POLITENESS OF EFL LEARNERS’ REQUEST REALIZATIONS

    Indawan Syahri

    2013-07-01

    Full Text Available Abstract: Politeness principles are universally utilized by the speakers of any language when realizing various speech acts. However, the speakers of particular languages relatively apply politeness due to the cultural norms embedded. The present study attempts to delineate how the Indonesian learners of English (ILE apply the politeness principles in request realizations. Specifically it devotes to the types of politeness strategies applied and resemblance of the indirectness in politeness strategies in requesting acts. The FTAs and indirectness are the theoretical bases used to trace the typologies of both politeness and request strategies. The data werere collected by means of certain elicitation techniques, i.e. DCTs and Role-plays. The analyses werere done through three stages; determining request strategies, politeness strategies, and resemblance of indirectness in politeness. The results show that the indirectness generally is parallel to politeness. Besides, some pragmatic transfers are found in terms of applying native-culture norms in realizing target speech acts.

  9. Inducible indirect defence of plants : from mechanisms to ecological functions

    Dicke, M.; Poecke, van R.M.P.; Boer, de J.G.

    2003-01-01

    Inducible defences allow plants to be phenotypically plastic. Inducible indirect defence of plants by attracting carnivorous enemies of herbivorous arthropods can vary with plant species and genotype, with herbivore species or instar and potentially with other environmental conditions. So far,

  10. Comparative analysis of direct and indirect property investment ...

    Comparative analysis of direct and indirect property investment returns in Abuja. ... in property shares is more risky than commercial property due to the risk ... of the stock market, it was discovered that there is a strong positive relationship ...

  11. Indirect reciprocity and the evolution of "moral signals"

    Smead, Rory

    2010-01-01

    Signals regarding the behavior of others are an essential element of human moral systems and there are important evolutionary connections between language and large-scale cooperation. In particular, social communication may be required for the reputation tracking needed to stabilize indirect reciprocity. Additionally, scholars have suggested that the benefits of indirect reciprocity may have been important for the evolution of language and that social signals may have coevolved with large-scale cooperation. This paper investigates the possibility of such a coevolution. Using the tools of evolutionary game theory, we present a model that incorporates primitive "moral signaling" into a simple setting of indirect reciprocity. This model reveals some potential difficulties for the evolution of "moral signals." We find that it is possible for "moral signals" to evolve alongside indirect reciprocity, but without some external pressure aiding the evolution of a signaling system, such a coevolution is unlikely.

  12. Theoretical and testing performance of an innovative indirect evaporative chiller

    Jiang, Yi; Xie, Xiaoyun [Department of Building Science and Technology, Tsinghua University, Beijing (China)

    2010-12-15

    An indirect evaporative chiller is a device used to produce chilled water at a temperature between the wet bulb temperature and dew point of the outdoor air, which can be used in building HVAC systems. This article presents a theoretical analysis and practical performance of an innovative indirect evaporative chiller. First, the process of the indirect evaporative chiller is introduced; then, the matching characteristics of the process are presented and analyzed. It can be shown that the process that produces cold water by using dry air is a nearly-reversible process, so the ideal produced chilled water temperature of the indirect evaporative chiller can be set close to the dew point temperature of the chiller's inlet air. After the indirect evaporative chiller was designed, simulations were done to analyze the output water temperature, the cooling efficiency relative to the inlet dew point temperature, and the COP that the chiller can performance. The first installation of the indirect evaporative chiller of this kind has been run for 5 years in a building in the city of Shihezi. The tested output water temperature of the chiller is around 14-20 C, which is just in between of the outdoor wet bulb temperature and dew point. The tested COP{sub r,s} of the developed indirect evaporative chiller reaches 9.1. Compared with ordinary air conditioning systems, the indirect evaporative chiller can save more than 40% in energy consumption due to the fact that the only energy consumed is from pumps and fans. An added bonus is that the indirect evaporative chiller uses no CFCs that pollute to the aerosphere. The tested internal parameters, such as the water-air flow rate ratio and heat transfer area for each heat transfer process inside the chiller, were analyzed and compared with designed values. The tested indoor air conditions, with a room temperature of 23-27 C and relative humidity of 50-70%, proved that the developed practical indirect evaporative chiller

  13. Ancestry of indirect techniques for X-ray imaging

    Mertz, L.

    1989-01-01

    Historical citations concerning the origins of coded-aperture imaging are corrected. Another scheme is presented for synthetic indirect imaging to overcome certain shortcomings of simple coded apertures. Pairs of Fresnel zone patterns are used to create moire patterns that can be Fourier transformed for image reconstruction. It is also conjectured that image reconstructions that are constrained to be nonnegative should overcome certain complaints concerning indirect imaging. 20 refs

  14. The indirect costs and benefits of greenhouse gas mitigation

    Markandya, A.

    1998-01-01

    The indirect costs of GHG projects are very important in the evaluation of such projects. In many cases they are more important than the direct costs. This paper has shown what such costs consist of and how they may be estimated. As countries prepare their mitigation strategies, it is very important that they develop tools for the assessment of these indirect costs and use these tools in the appropriate manner. Hopefully, this paper will point them in the right direction. (au) 11 refs

  15. The Indirect Costs of Financial Distress in Indonesia

    Wijantini, Wijantini

    2007-01-01

    This paper presents quantitative estimates of the indirect cost of financial distress and its determinants. In order to measure the cost, this study estimates the annualized changes in industry-adjusted operation profit and sales from a year before the onset of distress to the resolution year. Using those approaches, the median of indirect financial distress cost is estimated between three and 11 percent annually. To the extent that the direct cost of financial distress reduces reported opera...

  16. Light indirectly mediates bivalve habitat modification and impacts on seagrass

    Castorani, Max C. N.; Glud, Ronnie; Hasler-Sheetal, Harald

    2015-01-01

    Environmental context may influence the sign, strength, andmechanisms of species interactions but few studies have experimentally tested the potential for abiotic conditions to mediate interactions through multiple cooccurring stress pathways. Abiotic conditionsmay mediate species interactions...... by directly or indirectly influencing the effects of habitat-modifying organisms that are capable of simultaneously ameliorating and exacerbating multiple stressors. Itwas hypothesized that light availability changes seagrassmetabolismand thereby indirectly regulates bivalve habitat modification...

  17. Manifestation of Aerosol Indirect Effects in Arctic Clouds

    Lubin, D.; Vogelmann, A. M.

    2009-12-01

    The first aerosol indirect effect has traditionally been conceived as an enhancement of shortwave cloud reflectance in response to decreased effective droplet size at fixed liquid water path, as cloud nucleating aerosol becomes entrained in the cloud. The high Arctic, with its pervasive low-level stratiform cloud cover and frequent episodes of anthropogenic aerosol (Artic "haze"), has in recent years served as a natural laboratory for research on actual manifestations of aerosol indirect effects. This paper will review the surprising set of developments: (1) the detection of the indirect effect as a source of surface warming, rather than cooling, throughout early spring, (2) a transition to a cooling effect in late spring, corresponding to the beginning of the sea ice melt season, and (3) detection of an indirect effect during summer, outside of the "Arctic haze" season. This paper will also discuss measurements of spectral shortwave irradiance (350-2200 nm) made at Barrow, Alaska, during the U.S. Department of Energy's Indirect and Semi-Direct Aerosol Campaign (ISDAC), which reveal complications in our conception of the indirect effect related to the ice phase in Arctic stratiform clouds.

  18. Heard it through the grapevine: indirect networks and employee creativity.

    Hirst, Giles; Van Knippenberg, Daan; Zhou, Jing; Quintane, Eric; Zhu, Cherrie

    2015-03-01

    Social networks can be important sources of information and insights that may spark employee creativity. The cross-fertilization of ideas depends not just on access to information and insights through one's direct network-the people one actually interacts with--but at least as much on access to the indirect network one's direct ties connect one to (i.e., people one does not interact with directly, but with whom one's direct ties interact). We propose that the reach efficiency of this indirect network--its nonredundancy in terms of interconnections--is positively related to individual creativity. To help specify the boundaries of this positive influence of the indirect network, we also explore how many steps removed the indirect network still adds to creativity. In addition, we propose that the efficiency (nonredundancy) of one's direct network is important here, because more efficient direct networks give one access to indirect networks with greater reach efficiency. Our hypotheses were supported in a multilevel analysis of multisource survey data from 223 sales representatives nested within 11 divisions of a Chinese pharmaceutical company. This analysis also showed that the creative benefits of reach efficiency were evident for 3 and 4 degrees of separation but were greatest for indirect ties that depend only on one's direct ties. PsycINFO Database Record (c) 2015 APA, all rights reserved.

  19. Indirect methods for reference interval determination - review and recommendations.

    Jones, Graham R D; Haeckel, Rainer; Loh, Tze Ping; Sikaris, Ken; Streichert, Thomas; Katayev, Alex; Barth, Julian H; Ozarda, Yesim

    2018-04-19

    Reference intervals are a vital part of the information supplied by clinical laboratories to support interpretation of numerical pathology results such as are produced in clinical chemistry and hematology laboratories. The traditional method for establishing reference intervals, known as the direct approach, is based on collecting samples from members of a preselected reference population, making the measurements and then determining the intervals. An alternative approach is to perform analysis of results generated as part of routine pathology testing and using appropriate statistical techniques to determine reference intervals. This is known as the indirect approach. This paper from a working group of the International Federation of Clinical Chemistry (IFCC) Committee on Reference Intervals and Decision Limits (C-RIDL) aims to summarize current thinking on indirect approaches to reference intervals. The indirect approach has some major potential advantages compared with direct methods. The processes are faster, cheaper and do not involve patient inconvenience, discomfort or the risks associated with generating new patient health information. Indirect methods also use the same preanalytical and analytical techniques used for patient management and can provide very large numbers for assessment. Limitations to the indirect methods include possible effects of diseased subpopulations on the derived interval. The IFCC C-RIDL aims to encourage the use of indirect methods to establish and verify reference intervals, to promote publication of such intervals with clear explanation of the process used and also to support the development of improved statistical techniques for these studies.

  20. Preschool children's behavioral tendency toward social indirect reciprocity.

    Mayuko Kato-Shimizu

    Full Text Available Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers' prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers' prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children's prosocial behavior. In other words, observing peers' prosocial behavior toward third-party peers evoked bystanders' positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander's prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler's behavioral tendency toward social indirect reciprocity in natural interactions with peers.

  1. Preschool children's behavioral tendency toward social indirect reciprocity.

    Kato-Shimizu, Mayuko; Onishi, Kenji; Kanazawa, Tadahiro; Hinobayashi, Toshihiko

    2013-01-01

    Social indirect reciprocity seems to be crucial in enabling large-scale cooperative networks among genetically unrelated individuals in humans. However, there are relatively few studies on social indirect reciprocity in children compared to adults. Investigating whether young children have a behavioral tendency toward social indirect reciprocity will help us understand how and when the fundamental ability to form cooperative relationships among adults is acquired. Using naturalistic observation at a nursery school, this study examined whether 5- to 6-year-olds show a behavioral tendency to engage in social indirect reciprocity in response to their peers' prosocial behavior toward a third party. The results revealed that bystander children tended to display prosocial behavior toward their peers more frequently after observing these peers' prosocial behavior toward third-party peers, compared with control situations; this suggests that 5- to 6-year-olds may have an essential behavioral tendency to establish social indirect reciprocity when interacting with peers in their daily lives. In addition, bystanders tended to display affiliative behavior after observing focal children's prosocial behavior. In other words, observing peers' prosocial behavior toward third-party peers evoked bystanders' positive emotions toward the helpers. Considering both the present results and previous findings, we speculate that in preschoolers, such positive emotions might mediate the increase in the bystander's prosocial behavior toward the helper. In addition, an intuitional emotional process plays an important role in the preschooler's behavioral tendency toward social indirect reciprocity in natural interactions with peers.

  2. Direct and indirect effects of body weight on adult wages.

    Han, Euna; Norton, Edward C; Powell, Lisa M

    2011-12-01

    Previous estimates of the association between body weight and wages in the literature have been conditional on education and occupation. In addition to the effect of current body weight status (body mass index (BMI) or obesity) on wages, this paper examines the indirect effect of body weight status in the late-teenage years on wages operating through education and occupation choice. Using the National Longitudinal Survey of Youth 1979 data, for women, we find that a one-unit increase in BMI is directly associated with 1.83% lower hourly wages whereas the indirect BMI wage penalty is not statistically significant. Neither a direct nor an indirect BMI wage penalty is found for men. However, results based on clinical weight classification reveal that the indirect wage penalty occurs to a larger extent at the upper tail of the BMI distribution for both men and women via the pathways of education and occupation outcomes. Late-teen obesity is indirectly associated with 3.5% lower hourly wages for both women and men. These results are important because they imply that the total effect of obesity on wages is significantly larger than has been estimated in previous cross-sectional studies. 2011 Elsevier B.V. All rights reserved.

  3. Selection for components of complex characteristics - indirect selection

    Haensel, H.

    1984-01-01

    A hierarchy of complexity exists in plant characteristics. The efficiency of indirect selection for a complex characteristic by a sub-trait depends on the heritability of the complex characteristic (hsub(c)), the heritability of the sub-trait (hsub(s)), and the genotypic correlation between sub-trait and complex characteristic (rsub(s.c)). In 1961 hsub(s)Xrsub(s.c)>hsub(c) was postulated, when indirect selection becomes more efficient than direct selection. Numerical examples for this relationship are given and a table for indirect selection for yield in wheat is elaborated. Efficiency ranking of sub-traits in indirect selection may change with climate, conditions of cultivation, the level of other sub-traits, the level of the complex characteristic already reached by breeding, and the breeding material. An example shows that regression analysis for different sub-traits on the same complex characteristic, and an estimation of the differences of the within - and the between - variety slopes, may help to select the more efficient sub-trait. In another example, where simultaneous selection was made for two polygenic characteristics, one directly and the other indirectly by two sub-traits, less than half the F 5 -lines had to be continued, when using the more efficient sub-trait. (author)

  4. Supporting Risk Assessment: Accounting for Indirect Risk to Ecosystem Components.

    Cathryn Clarke Murray

    Full Text Available The multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. Risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. In this case study from British Columbia, Canada, we illustrate how such "indirect risks" can be incorporated into risk assessments for seventeen ecosystem components. We ask whether (i the addition of indirect risk changes the at-risk ranking of the seventeen ecosystem components and if (ii risk scores correlate with trophic prey and habitat linkages in the food web. Even with conservative assumptions about the transfer of impacts or risks from prey species and habitats, the addition of indirect risks in the cumulative risk score changes the ranking of priorities for management. In particular, resident orca, Steller sea lion, and Pacific herring all increase in relative risk, more closely aligning these species with their "at-risk status" designations. Risk assessments are not a replacement for impact assessments, but-by considering the potential for indirect risks as we demonstrate here-they offer a crucial complementary perspective for the management of ecosystems and the organisms within.

  5. Supporting Risk Assessment: Accounting for Indirect Risk to Ecosystem Components

    Mach, Megan E.; Martone, Rebecca G.; Singh, Gerald G.; O, Miriam; Chan, Kai M. A.

    2016-01-01

    The multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. Risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. In this case study from British Columbia, Canada, we illustrate how such “indirect risks” can be incorporated into risk assessments for seventeen ecosystem components. We ask whether (i) the addition of indirect risk changes the at-risk ranking of the seventeen ecosystem components and if (ii) risk scores correlate with trophic prey and habitat linkages in the food web. Even with conservative assumptions about the transfer of impacts or risks from prey species and habitats, the addition of indirect risks in the cumulative risk score changes the ranking of priorities for management. In particular, resident orca, Steller sea lion, and Pacific herring all increase in relative risk, more closely aligning these species with their “at-risk status” designations. Risk assessments are not a replacement for impact assessments, but—by considering the potential for indirect risks as we demonstrate here—they offer a crucial complementary perspective for the management of ecosystems and the organisms within. PMID:27632287

  6. Indirect reciprocity in three types of social dilemmas.

    Nakamura, Mitsuhiro; Ohtsuki, Hisashi

    2014-08-21

    Indirect reciprocity is a key mechanism for the evolution of human cooperation. Previous studies explored indirect reciprocity in the so-called donation game, a special class of Prisoner's Dilemma (PD) with unilateral decision making. A more general class of social dilemmas includes Snowdrift (SG), Stag Hunt (SH), and PD games, where two players perform actions simultaneously. In these simultaneous-move games, moral assessments need to be more complex; for example, how should we evaluate defection against an ill-reputed, but now cooperative, player? We examined indirect reciprocity in the three social dilemmas and identified twelve successful social norms for moral assessments. These successful norms have different principles in different dilemmas for suppressing cheaters. To suppress defectors, any defection against good players is prohibited in SG and PD, whereas defection against good players may be allowed in SH. To suppress unconditional cooperators, who help anyone and thereby indirectly contribute to jeopardizing indirect reciprocity, we found two mechanisms: indiscrimination between actions toward bad players (feasible in SG and PD) or punishment for cooperation with bad players (effective in any social dilemma). Moreover, we discovered that social norms that unfairly favor reciprocators enhance robustness of cooperation in SH, whereby reciprocators never lose their good reputation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Circumventing resistance: using values to indirectly change attitudes.

    Blankenship, Kevin L; Wegener, Duane T; Murray, Renee A

    2012-10-01

    Most research on persuasion examines messages that directly address the attitude of interest. However, especially when message recipients are inclined to resist change, indirect methods might be more effective. Because values are rarely attacked and defended, value change could serve as a useful indirect route for attitude change. Attitudes toward affirmative action changed more when the value of equality was attacked (indirect change) than when affirmative action was directly attacked using the same message (Experiments 1-2). Changes in confidence in the value were responsible for the indirect change when the value was attacked (controlling for changes in favorability toward the value), whereas direct counterarguments to the message were responsible for the relative lack of change when the attitude was attacked directly (Experiment 2). Attacking the value of equality influenced attitudes toward policies related to the value but left policy attitudes unrelated to the value unchanged (Experiment 3). Finally, a manipulation of value confidence that left attitudes toward the value intact demonstrated similar confidence-based influences on policies related to the value of freedom (Experiment 4). Undermined value confidence also resulted in less confidence in the resulting policy attitudes controlling for the changes in the policy attitudes themselves (Experiments 3 and 4). Therefore, indirect change through value attacks presented a double threat--to both the policy attitudes and the confidence with which those policy attitudes were held (potentially leaving them open to additional influence).

  8. Congenital Anophthalmia and Binocular Neonatal Enucleation Differently Affect the Proteome of Primary and Secondary Visual Cortices in Mice.

    Marie-Eve Laramée

    Full Text Available In blind individuals, visually deprived occipital areas are activated by non-visual stimuli. The extent of this cross-modal activation depends on the age at onset of blindness. Cross-modal inputs have access to several anatomical pathways to reactivate deprived visual areas. Ectopic cross-modal subcortical connections have been shown in anophthalmic animals but not in animals deprived of sight at a later age. Direct and indirect cross-modal cortical connections toward visual areas could also be involved, yet the number of neurons implicated is similar between blind mice and sighted controls. Changes at the axon terminal, dendritic spine or synaptic level are therefore expected upon loss of visual inputs. Here, the proteome of V1, V2M and V2L from P0-enucleated, anophthalmic and sighted mice, sharing a common genetic background (C57BL/6J x ZRDCT/An, was investigated by 2-D DIGE and Western analyses to identify molecular adaptations to enucleation and/or anophthalmia. Few proteins were differentially expressed in enucleated or anophthalmic mice in comparison to sighted mice. The loss of sight affected three pathways: metabolism, synaptic transmission and morphogenesis. Most changes were detected in V1, followed by V2M. Overall, cross-modal adaptations could be promoted in both models of early blindness but not through the exact same molecular strategy. A lower metabolic activity observed in visual areas of blind mice suggests that even if cross-modal inputs reactivate visual areas, they could remain suboptimally processed.

  9. Congenital Anophthalmia and Binocular Neonatal Enucleation Differently Affect the Proteome of Primary and Secondary Visual Cortices in Mice.

    Laramée, Marie-Eve; Smolders, Katrien; Hu, Tjing-Tjing; Bronchti, Gilles; Boire, Denis; Arckens, Lutgarde

    2016-01-01

    In blind individuals, visually deprived occipital areas are activated by non-visual stimuli. The extent of this cross-modal activation depends on the age at onset of blindness. Cross-modal inputs have access to several anatomical pathways to reactivate deprived visual areas. Ectopic cross-modal subcortical connections have been shown in anophthalmic animals but not in animals deprived of sight at a later age. Direct and indirect cross-modal cortical connections toward visual areas could also be involved, yet the number of neurons implicated is similar between blind mice and sighted controls. Changes at the axon terminal, dendritic spine or synaptic level are therefore expected upon loss of visual inputs. Here, the proteome of V1, V2M and V2L from P0-enucleated, anophthalmic and sighted mice, sharing a common genetic background (C57BL/6J x ZRDCT/An), was investigated by 2-D DIGE and Western analyses to identify molecular adaptations to enucleation and/or anophthalmia. Few proteins were differentially expressed in enucleated or anophthalmic mice in comparison to sighted mice. The loss of sight affected three pathways: metabolism, synaptic transmission and morphogenesis. Most changes were detected in V1, followed by V2M. Overall, cross-modal adaptations could be promoted in both models of early blindness but not through the exact same molecular strategy. A lower metabolic activity observed in visual areas of blind mice suggests that even if cross-modal inputs reactivate visual areas, they could remain suboptimally processed.

  10. Direct and Indirect Effects of PM on the Cardiovascular System

    Nelin, Timothy D.; Joseph, Allan M.; Gorr, Matthew W.; Wold, Loren E.

    2011-01-01

    Human exposure to particulate matter (PM) elicits a variety of responses on the cardiovascular system through both direct and indirect pathways. Indirect effects of PM on the cardiovascular system are mediated through the autonomic nervous system, which controls heart rate variability, and inflammatory responses, which augment acute cardiovascular events and atherosclerosis. Recent research demonstrates that PM also affects the cardiovascular system directly by entry into the systemic circulation. This process causes myocardial dysfunction through mechanisms of reactive oxygen species production, calcium ion interference, and vascular dysfunction. In this review, we will present key evidence in both the direct and indirect pathways, suggest clinical applications of the current literature, and recommend directions for future research. PMID:22119171

  11. An improved recommendation algorithm via weakening indirect linkage effect

    Chen, Guang; Qiu, Tian; Shen, Xiao-Quan

    2015-07-01

    We propose an indirect-link-weakened mass diffusion method (IMD), by considering the indirect linkage and the source object heterogeneity effect in the mass diffusion (MD) recommendation method. Experimental results on the MovieLens, Netflix, and RYM datasets show that, the IMD method greatly improves both the recommendation accuracy and diversity, compared with a heterogeneity-weakened MD method (HMD), which only considers the source object heterogeneity. Moreover, the recommendation accuracy of the cold objects is also better elevated in the IMD than the HMD method. It suggests that eliminating the redundancy induced by the indirect linkages could have a prominent effect on the recommendation efficiency in the MD method. Project supported by the National Natural Science Foundation of China (Grant No. 11175079) and the Young Scientist Training Project of Jiangxi Province, China (Grant No. 20133BCB23017).

  12. The Indirect Costs of Financial Distress in Indonesia

    Wijantini Wijantini

    2007-06-01

    Full Text Available This paper presents quantitative estimates of the indirect cost of financial distress and its determinants. In order to measure the cost, this study estimates the annualized changes in industry-adjusted operation profit and sales from a year before the onset of distress to the resolution year. Using those approaches, the median of indirect financial distress cost is estimated between three and 11 percent annually. To the extent that the direct cost of financial distress reduces reported operating income, the estimated costs are overstated. The simple regressions analysis suggest that the indirect cost of financial distress significantly increases with size, leverage, number of creditors, and poor industry performance, but is not related to degree of bank loan reliance. The findings provide a weak support for the financial distress theory which suggests that conflicts of interest render the costs of financial distress.

  13. Indirect control of flexible demand for power system applications

    Sossan, Fabrizio

    This thesis addresses the topic of control of flexible demand to provide support to the operation of the electric power system. We focus on the indirect control approach, a framework that enables demand response by means of a consumption incentive signal. Initially, the concept of flexibility...... a shift in the consumption according to an indirect control signal. We present from simple control algorithms with a few requirements up to model predictive control strategies. The performance of the indirect control algorithms are compared by means of hardware-in-the-loop simulations using Power...... and storage in the operation of the future power system, we develop a model predictive control strategy for a smart building with the objective of supplying iii space heating and providing regulating power to the grid according to a dynamic electricity price. We named this application energy replacement...

  14. Shear bond strength of indirect composite material to monolithic zirconia.

    Sari, Fatih; Secilmis, Asli; Simsek, Irfan; Ozsevik, Semih

    2016-08-01

    This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI). Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (α=.05). Bond strength was significantly lower in untreated specimens than in sandblasted specimens (Pcomposite material and monolithic zirconia.

  15. Stability Concerns for Indirect Consumer Control in Smart Grids

    Juelsgaard, Morten; Andersen, Palle; Wisniewski, Rafal

    2013-01-01

    by an external third party, and indirect consumer control through incentives and price signals. In this work we present a simple formulation of indirect control, where the behavior of each consumer, is governed by local optimization of energy consumption. The local optimization accounts for both cost of energy...... and distribution losses, as well as any discomfort incurred by consumers from any shift in energy consumption. Our work will illustrate that in the simplest formulation of indirect control, the stability is greatly affected of both the behavior of consumers, and the number of consumers to include. We will show how......Demand side management will be an important tool for maintaining a balanced electrical grid in the future, when the penetration of volatile resources, such as wind and solar energy increases. Recent research focuses on two different management approaches, namely direct consumer control...

  16. Estimating direct and indirect costs of premenstrual syndrome.

    Borenstein, Jeff; Chiou, Chiun-Fang; Dean, Bonnie; Wong, John; Wade, Sally

    2005-01-01

    To quantify the economic impact of premenstrual syndrome (PMS) on the employer. Data were collected from 374 women aged 18-45 with regular menses. Direct costs were quantified using administrative claims of these patients and the Medicare Fee Schedule. Indirect costs were quantified by both self-reported days of work missed and lost productivity at work. Regression analyses were used to develop a model to project PMS-related direct and indirect costs. A total of 29.6% (n = 111) of the participants were diagnosed with PMS. A PMS diagnosis was associated with an average annual increase of $59 in direct costs (P increase in direct medical costs and a large increase in indirect costs.

  17. Direct and indirect pathways for choosing objects and actions.

    Hikosaka, Okihide; Kim, Hyoung F; Amita, Hidetoshi; Yasuda, Masaharu; Isoda, Masaki; Tachibana, Yoshihisa; Yoshida, Atsushi

    2018-02-23

    A prominent target of the basal ganglia is the superior colliculus (SC) which controls gaze orientation (saccadic eye movement in primates) to an important object. This 'object choice' is crucial for choosing an action on the object. SC is innervated by the substantia nigra pars reticulata (SNr) which is controlled mainly by the caudate nucleus (CD). This CD-SNr-SC circuit is sensitive to the values of individual objects and facilitates saccades to good objects. The object values are processed differently in two parallel circuits: flexibly by the caudate head (CDh) and stably by the caudate tail (CDt). To choose good objects, we need to reject bad objects. In fact, these contrasting functions are accomplished by the circuit originating from CDt: The direct pathway focuses on good objects and facilitates saccades to them; the indirect pathway focuses on bad objects and suppresses saccades to them. Inactivation of CDt deteriorated the object choice, because saccades to bad objects were no longer suppressed. This suggests that the indirect pathway is important for object choice. However, the direct and indirect pathways for 'object choice', which aim at the same action (i.e., saccade), may not work for 'action choice'. One possibility is that circuits controlling different actions are connected through the indirect pathway. Additional connections of the indirect pathway with brain areas outside the basal ganglia may also provide a wider range of behavioral choice. In conclusion, basal ganglia circuits are composed of the basic direct/indirect pathways and additional connections and thus have acquired multiple functions. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  18. INDIRECT TAXATION TRENDS IN THE EUROPEAN UNION MEMBER STATES

    MARIUS CRISTIAN MILOŞ

    2014-12-01

    Full Text Available The objective of this paper is to outline the recent dynamics of the indirect taxation in the European Union member states, with a special focus on the Romanian case. We could notice that indirect taxation continues to play an important role for all the member states, in their attempt to recover from the global economic crisis. Morover, we have presented some of the recent changes in the legislative frameworks, which happened with a rather rapid pace, and contributed to a rather challenging business climate.

  19. Neutron-capture cross sections from indirect measurements

    Scielzo N.D.

    2012-02-01

    Full Text Available Cross sections for compound-nuclear reactions reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f reactions, but need to be improved upon for applications to capture reactions.

  20. Direct and indirect welfare chauvinism as party strategies

    Careja, Romana; Elmelund-Præstekær, Christian; Klitgaard, Michael Baggesen

    2016-01-01

    welfare chauvinism occurs as a result of legislative changes that explicitly exclude recipients from social protection or reduce the level thereof on the basis of ethnicity. Indirect welfare chauvinism is the result of policy measures that apply to both natives and immigrants, but which deliberately...... and deliberate policy-making strategies of the party. It shows that the distinction between direct and indirect chauvinism is a useful theoretical tool for understanding how the Danish People's Party can fulfill the expectations of both its electorate and its coalition partners, even if they point in different...

  1. Indirect Fluorescent Antibody Technique based Prevalence of Surra in Equines

    Ahsan Nadeem, Asim Aslam*, Zafar Iqbal Chaudhary, Kamran Ashraf1, Khalid Saeed1, Nisar Ahmad1, Ishtiaq Ahmed and Habib ur Rehman2

    2011-04-01

    Full Text Available This project was carried out to find the prevalence of trypanosomiasis in equine in District Gujranwala by using indirect fluorescent antibody technique and thin smear method. Blood samples were collected from a total of 200 horses and donkeys of different ages and either sex. Duplicate thin blood smears were prepared from each sample and remaining blood samples were centrifuged to separate the serum. Smears from each animal were processed for giemsa staining and indirect fluorescent antibody test (IFAT. Giemsa stained smears revealed Trypanosome infection in 4/200 (2.0% samples and IFAT in 12/200 (6.0% animals.

  2. Direct and indirect two-photon processes in semiconductors

    Hassan, A.R.

    1986-07-01

    The expressions describing direct and indirect two-photon absorption in crystals are given. They are valid both near and far from the energy gap. A perturbative approach through two different band models is adopted. The effects of the non-parabolicity and the degeneracy of the energy bands are considered. The numerical results are compared with the other theories and with a recent experimental data in Zn and AgCl. It is shown that the dominant transition mechanisms are of the allowed-allowed type near and far from the gap for both direct and indirect processes. (author)

  3. Neutron-capture Cross Sections from Indirect Measurements

    Escher, J E; Burke, J T; Dietrich, F S; Ressler, J J; Scielzo, N D; Thompson, I J

    2011-10-18

    Cross sections for compound-nuclear reactions play an important role in models of astrophysical environments and simulations of the nuclear fuel cycle. Providing reliable cross section data remains a formidable task, and direct measurements have to be complemented by theoretical predictions and indirect methods. The surrogate nuclear reactions method provides an indirect approach for determining cross sections for reactions on unstable isotopes, which are difficult or impossible to measure otherwise. Current implementations of the method provide useful cross sections for (n,f) reactions, but need to be improved upon for applications to capture reactions.

  4. Indirect search for neutralino dark matter with high energy neutrinos

    Barger, V.; Halzen, Francis; Hooper, Dan; Kao, Chung

    2002-01-01

    We investigate the prospects of indirect searches for supersymmetric neutralino dark matter. Relic neutralinos gravitationally accumulate in the Sun and their annihilations produce high energy neutrinos. Muon neutrinos of this origin can be seen in large detectors such as AMANDA, IceCube, and ANTARES. We evaluate the relic density and the detection rate in several models--the minimal supersymmetric model, minimal supergravity, and supergravity with nonuniversal Higgs boson masses at the grand unification scale. We make realistic estimates for the indirect detection rates including effects of the muon detection threshold, quark hadronization, and solar absorption. We find good prospects for detection of neutralinos with mass above 200 GeV

  5. Water augmented indirectly-fired gas turbine systems and method

    Bechtel, Thomas F.; Parsons, Jr., Edward J.

    1992-01-01

    An indirectly-fired gas turbine system utilizing water augmentation for increasing the net efficiency and power output of the system is described. Water injected into the compressor discharge stream evaporatively cools the air to provide a higher driving temperature difference across a high temperature air heater which is used to indirectly heat the water-containing air to a turbine inlet temperature of greater than about 1,000.degree. C. By providing a lower air heater hot side outlet temperature, heat rejection in the air heater is reduced to increase the heat recovery in the air heater and thereby increase the overall cycle efficiency.

  6. Testing indirect effect of consumer attitudes toward a product

    Hrubá, Renata; Sudzina, Frantisek

    2016-01-01

    a questionnaire in 2010-2011. The model is estimated using probit analysis to predict relationship between producer and consumer in decision-making when buying a new type of cheese and to examine consumer attitudes toward food origins and nutrient food security. It can be concluded that the indirect effect (e...... and on the indirect and direct effects of the perception of information through information behavior and the use of the model ordered. It is proposed that consumer levels of product familiarity of attributes affects behavior. Consumer attitudes towards agri-food products and behaviour were analyzed through...

  7. Fistule carotido-caverneuse indirecte post traumatique: diagnostic ...

    The indirect carotido-cavernous fistula is an abnormal communication between multiple arterioles coming from dural or meningeal branches of the external carotid artery and/or of the internal carotid artery and the cavernous sinus. Its definitive diagnosis relies on carotid angiography showing the fistula. This imaging ...

  8. Effects of Direct and Indirect Instructional Strategies on Students ...

    First Lady

    2012-10-27

    Oct 27, 2012 ... Counseling, University of Port Harcourt, Rivers State. Phone: +234(0) ... Mathematics using Direct Instructional strategy, while Group B students were taught using ... strategy; significant difference existed between direct and indirect instruction ..... is to ensure individual student's mastery of the subject matter.

  9. Determination of cyanide by a highly sensitive indirect spectrophotometric method.

    Blanco, M; Maspoch, S

    1984-01-01

    Complexation of Pd(2+) with cyanide inhibits the extraction of the palladium complex of 5-phenylazo-8-aminoquinoline. This effect is used for the indirect spectrophotometric determination of cyanide at the mug level. Cyanide in industrial waste water and in sea-water is determined after distillation as HCN from the sample and collection in sodium hydroxide solution.

  10. A comparison of microhardness of indirect composite restorative materials

    Miranda, Carolina Baptista; Pagani, Clóvis; Bottino, Marco Cícero

    2003-01-01

    The purpose of this study was to compare the microhardness of four indirect composite resins. Forty cylindrical samples were prepared according to the manufacturer’s recommendations using a Teflon mold. Ten specimens were produced from each tested material, constituting four groups (n=10) as foll...... esthetics and adequate mechanical properties may be considered as substitutes of natural teeth....

  11. Direct versus indirect detection of supersymmetric dark matter

    NONE

    2003-07-01

    This document gathers the slides that were presented during the workshop 'direct versus indirect detection of supersymmetric dark matter'(about 30 contributions). This workshop intended to bring together people from the particle theory community, astrophysicists and cosmologists, as well as experimentalists involved in the detection of dark matter. The aim is to generate a discussion about current and future strategies for detection of SUSY dark matter (with focus, but not exclusively, on neutralinos). Complementarities between accelerator, direct and indirect searches as well as a comparison between the uncertainties in direct and indirect searches of dark matter, are supposed to be discussed. Among the issues which will be addressed are: -) the crucial questions related to the structure of galaxies (local dark matter density, clumping, anomalous velocity distributions, etc.) ; -) the possibilities offered by the present and future experimental facilities for direct and indirect (photon, neutrino) searches; -) the potential for the discovery of SUSY at LHC and beyond; and -) the parameterization of the SUSY breaking models beyond the minimal versions.

  12. Pulsewidth Modulation of Neutral-Point-Clamped Indirect Matrix Converter

    Blaabjerg, Frede; Poh Chiang, Loh; Gao, Feng

    2008-01-01

    An indirect matrix converter is an alternative "all-semiconductor" energy processor proposed recently for converting an ac source with fixed magnitude and frequency to a variable voltage and frequency supply that can meet the requirements of a particular industry application. In principle...

  13. Biological production of alcohols from coal through indirect liquefaction

    Barik, S; Prieto, S; Harrison, S B; Clausen, E C; Gaddy, J L

    1988-08-01

    The purpose of this project is to demonstrate the feasibility of producing liquid fuels from the components of synthesis gas through biological indirect liquefaction. The results of pure culture and natural source screening studies aimed at finding organisms capable of carrying out the conversions are presented and discussed. 17 refs., 2 figs., 8 tabs.

  14. Silent, indirect strategic processes in small and medium sized enterprises

    Larsen, Mette Vinther; Madsen, Charlotte Øland; Rasmussen, Jørgen Gulddahl

    Based on empirical data we in this paper explore day-to-day strategising with an emphasis on phronesis. This way we shed some light on the nearly silent, quiet, indirect strategic change processes as they are practiced and reflected upon by leaders in small companies in their daily practice...

  15. Direct versus indirect detection of supersymmetric dark matter

    2003-01-01

    This document gathers the slides that were presented during the workshop 'direct versus indirect detection of supersymmetric dark matter'(about 30 contributions). This workshop intended to bring together people from the particle theory community, astrophysicists and cosmologists, as well as experimentalists involved in the detection of dark matter. The aim is to generate a discussion about current and future strategies for detection of SUSY dark matter (with focus, but not exclusively, on neutralinos). Complementarities between accelerator, direct and indirect searches as well as a comparison between the uncertainties in direct and indirect searches of dark matter, are supposed to be discussed. Among the issues which will be addressed are: -) the crucial questions related to the structure of galaxies (local dark matter density, clumping, anomalous velocity distributions, etc.) ; -) the possibilities offered by the present and future experimental facilities for direct and indirect (photon, neutrino) searches; -) the potential for the discovery of SUSY at LHC and beyond; and -) the parameterization of the SUSY breaking models beyond the minimal versions

  16. Current indirect fitness and future direct fitness are not incompatible.

    Brahma, Anindita; Mandal, Souvik; Gadagkar, Raghavendra

    2018-02-01

    In primitively eusocial insects, many individuals function as workers despite being capable of independent reproduction. Such altruistic behaviour is usually explained by the argument that workers gain indirect fitness by helping close genetic relatives. The focus on indirect fitness has left open the question of whether workers are also capable of getting direct fitness in the future in spite of working towards indirect fitness in the present. To investigate this question, we recorded behavioural profiles of all wasps on six naturally occurring nests of Ropalidia marginata , and then isolated all wasps in individual plastic boxes, giving them an opportunity to initiate nests and lay eggs. We found that 41% of the wasps successfully did so. Compared to those that failed to initiate nests, those that did were significantly younger, had significantly higher frequency of self-feeding behaviour on their parent nests but were not different in the levels of work performed in the parent nests. Thus ageing and poor feeding, rather than working for their colonies, constrain individuals for future independent reproduction. Hence, future direct fitness and present work towards gaining indirect fitness are not incompatible, making it easier for worker behaviour to be selected by kin selection or multilevel selection. © 2018 The Author(s).

  17. Strong impacts on aerosol indirect effects from historical oxidant changes

    Hafsahl Karset, Inger Helene; Koren Berntsen, Terje; Storelvmo, Trude; Alterskjær, Kari; Grini, Alf; Olivié, Dirk; Kirkevåg, Alf; Seland, Øyvind; Iversen, Trond; Schulz, Michael

    2018-06-01

    Uncertainties in effective radiative forcings through aerosol-cloud interactions (ERFaci, also called aerosol indirect effects) contribute strongly to the uncertainty in the total preindustrial-to-present-day anthropogenic forcing. Some forcing estimates of the total aerosol indirect effect are so negative that they even offset the greenhouse gas forcing. This study highlights the role of oxidants in modeling of preindustrial-to-present-day aerosol indirect effects. We argue that the aerosol precursor gases should be exposed to oxidants of its era to get a more correct representation of secondary aerosol formation. Our model simulations show that the total aerosol indirect effect changes from -1.32 to -1.07 W m-2 when the precursor gases in the preindustrial simulation are exposed to preindustrial instead of present-day oxidants. This happens because of a brightening of the clouds in the preindustrial simulation, mainly due to large changes in the nitrate radical (NO3). The weaker oxidative power of the preindustrial atmosphere extends the lifetime of the precursor gases, enabling them to be transported higher up in the atmosphere and towards more remote areas where the susceptibility of the cloud albedo to aerosol changes is high. The oxidation changes also shift the importance of different chemical reactions and produce more condensate, thus increasing the size of the aerosols and making it easier for them to activate as cloud condensation nuclei.

  18. Strong impacts on aerosol indirect effects from historical oxidant changes

    I. H. H. Karset

    2018-06-01

    Full Text Available Uncertainties in effective radiative forcings through aerosol–cloud interactions (ERFaci, also called aerosol indirect effects contribute strongly to the uncertainty in the total preindustrial-to-present-day anthropogenic forcing. Some forcing estimates of the total aerosol indirect effect are so negative that they even offset the greenhouse gas forcing. This study highlights the role of oxidants in modeling of preindustrial-to-present-day aerosol indirect effects. We argue that the aerosol precursor gases should be exposed to oxidants of its era to get a more correct representation of secondary aerosol formation. Our model simulations show that the total aerosol indirect effect changes from −1.32 to −1.07 W m−2 when the precursor gases in the preindustrial simulation are exposed to preindustrial instead of present-day oxidants. This happens because of a brightening of the clouds in the preindustrial simulation, mainly due to large changes in the nitrate radical (NO3. The weaker oxidative power of the preindustrial atmosphere extends the lifetime of the precursor gases, enabling them to be transported higher up in the atmosphere and towards more remote areas where the susceptibility of the cloud albedo to aerosol changes is high. The oxidation changes also shift the importance of different chemical reactions and produce more condensate, thus increasing the size of the aerosols and making it easier for them to activate as cloud condensation nuclei.

  19. Estimating forest canopy bulk density using six indirect methods

    Robert E. Keane; Elizabeth D. Reinhardt; Joe Scott; Kathy Gray; James Reardon

    2005-01-01

    Canopy bulk density (CBD) is an important crown characteristic needed to predict crown fire spread, yet it is difficult to measure in the field. Presented here is a comprehensive research effort to evaluate six indirect sampling techniques for estimating CBD. As reference data, detailed crown fuel biomass measurements were taken on each tree within fixed-area plots...

  20. Social Dilemmas and Indirect Reciprocity: A systematic review

    Cristian Acosta

    2014-08-01

    Full Text Available Indirect reciprocity is an evolutionary theory of altruism and cooperation in social dilemmas. Its explanation of cooperation incorporates information on the reputation people hold of other people regarding whether they are cooperative or not. This study systematically reviewed the current empirical literature on indirect reciprocity in social dilemma situations. The following databases were consulted: ScienceDirect, EBSCO, and OVID, using has key words "indirect reciprocity" AND "dilemma" OR "cooperation" OR "charity". Twenty-three articles were selected which met the inclusion criteria (papers written in English and studies whose methodology was based on experimental games and the theories, objectives, the main types of samples used, and main results were analyzed. The results show that the games used were the indirect reciprocity and public goods games, which may vary according to the objectives. It was found that reputation is a key variable that helps to promote cooperation. In turn, information on previous cooperation helps to build reputation, which is subsequently involved in the decision to cooperate with others. Finally, we highlight the need for more experimental studies that incorporate other explanatory variables and evaluate them in new contexts.

  1. Vocabulary Acquisition through Direct and Indirect Learning Strategies

    Naeimi, Maki; Foo, Thomas Chow Voon

    2015-01-01

    Vocabulary learning has long been considered as one of the essential components for developing language learning. However, language learners are required to not just concern about memorizing definitions but also integrating vocabulary meaning into their present knowledge. Many strategies such as direct or indirect ones may be integrated to enhance…

  2. 48 CFR 52.216-15 - Predetermined Indirect Cost Rates.

    2010-10-01

    .... (c) Allowability of costs and acceptability of cost allocation methods shall be determined in...) the period for which the rates apply, and (4) the specific items treated as direct costs or any changes in the items previously agreed to be direct costs. The indirect cost rate agreement shall not...

  3. Indirect environmental effects of nuclear war affecting health

    Leaf, A.

    1984-01-01

    The indirect effects of a nuclear war that will affect the health of survivors are considered to include consequences to: (a) the economies of nations, (b) food and nutrition, (c) water supplies, (d) the climate and the ecosphere, and (e) sanitation and public health; and they include long-term radiation effects

  4. Effects of Direct and Indirect Instructional Strategies on Students ...

    This is a quasi experimental research designed to determine the effects of Direct and Indirect instructional strategies on Mathematics achievement among junior secondary school students. The population consisted of students in a Public Secondary School in Owerri, Imo State. A sample of 102 students from two (2) intact ...

  5. Estimating two indirect logging costs caused by accelerated erosion.

    Glen O. Klock

    1976-01-01

    In forest areas where high soil erosion potential exists, a comparative yarding cost estimate, including the indirect costs determined by methods proposed here, shows that the total cost of using "advanced" logging methods may be less than that of "traditional" systems.

  6. 48 CFR 49.303-4 - Adjustment of indirect costs.

    2010-10-01

    ... costs. 49.303-4 Section 49.303-4 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TERMINATION OF CONTRACTS Additional Principles for Cost-Reimbursement Contracts... compute indirect costs for other contracts performed during the applicable accounting period. [48 FR 42447...

  7. 23 CFR 140.907 - Overhead and indirect construction costs.

    2010-04-01

    ... accounting principles; (2) The costs included in the distribution are limited to costs actually incurred by...), part 31, Contract Cost Principles and Procedures, relating to contracts with commercial organizations... 23 Highways 1 2010-04-01 2010-04-01 false Overhead and indirect construction costs. 140.907...

  8. Indirect self-destructiveness in individuals with schizophrenia

    Konstantinos Tsirigotis

    2017-06-01

    Full Text Available Objective: To explore the indirect self-destructiveness syndrome in patients with schizophrenia. Methods: Two hundred individuals with paranoid schizophrenia (117 men and 83 women, mean age 37.15 years, all in remission, were examined using the Polish version of the Chronic Self-Destructiveness Scale. Two hundred well-matched healthy individuals served as a control group. Results: The intensity of indirect self-destructiveness was greater in the schizophrenia group than in controls. The intensity of each manifestation was as follows (in decreasing order: helplessness and passiveness in the face of difficulties (A5, personal and social neglects (A3, lack of planfulness (A4, poor health maintenance (A2, transgression and risk (A1. Conclusion: Patients with schizophrenia displayed more behaviors that were indirectly self-destructive than healthy controls; they scored better than healthy controls only on caring for their own health. The patients showed the lowest intensity of behaviors connected with the active form of indirect self-destructiveness, and the highest intensity of behaviors connected with the passive form. These findings may enable delivery of more effective forms of pharmacological and psychosocial help to patients with schizophrenia.

  9. Indirect calorimetry: assessing animal response to heat and cold stress

    Gaughan, J.B.; Heetkamp, M.J.W.; Hendriks, P.

    2015-01-01

    Calorimetric thermal stress studies where indirect calorimetry is used as a tool to estimate energy expenditure have been undertaken since this technique was developed. Some examples of these studies are presented in this chapter. The measurement of gas exchange by means of an open-circuit

  10. STEM Faculty and Indirect Costs: What Administrators Need to Know

    Gossman, Susan

    2016-01-01

    The focus of this single site, qualitative case study was on public research university STEM (science, technology, engineering and mathematics) faculty and their perspectives on, and behavior towards, indirect cost recovery. The explanatory scheme was derived from anthropological theory and incorporated organizational culture, resource dependency…

  11. U.S. DOE indirect coal liquefaction program: An overview

    Shen, J.; Schmetz, E.; Winslow, J.; Tischer, R. [Dept. of Energy, Germantown, MD (United States); Srivastava, R.

    1997-12-31

    Coal is the most abundant domestic energy resource in the United States. The Fossil Energy Organization within the US Department of Energy (DOE) has been supporting a coal liquefaction program to develop improved technologies to convert coal to clean and cost-effective liquid fuels to complement the dwindling supply of domestic petroleum crude. The goal of this program is to produce coal liquids that are competitive with crude at $20 to $25 per barrel. Indirect and direct liquefaction routes are the two technologies being pursued under the DOE coal liquefaction program. This paper will give an overview of the DOE indirect liquefaction program. More detailed discussions will be given to the F-T diesel and DME fuels which have shown great promises as clean burning alternative diesel fuels. The authors also will briefly discuss the economics of indirect liquefaction and the hurdles and opportunities for the early commercial deployment of these technologies. Discussions will be preceded by two brief reviews on the liquid versus gas phase reactors and the natural gas versus coal based indirect liquefaction.

  12. Contribution of indirect obstetric deaths to maternal mortality at ...

    Introduction: Maternal death is unacceptably high in this center like in most centers in the developing world. Objective: To determine the maternal mortality ratio and the contribution of the direct and indirect obstetric complications to maternal deaths. Method: A retrospective review of all maternal deaths at Nnamdi Azikiwe ...

  13. In vitro and in vivo Comparison of Orthodontic Indirect Bonding ...

    2018-05-22

    May 22, 2018 ... 2018 Nigerian Journal of Clinical Practice | Published by Wolters Kluwer ‑ Medknow. Objective: The aim of this study was to evaluate in vitro shear bond strength ... with indirect bonding resins that were either chemically or light-cured. ...... strength of composite, glass ionomer, and acidic primer adhesive.

  14. Special considerations regarding indirect expropriation in international economic law

    Laura-Cristiana Spătaru-Negură

    2017-12-01

    Full Text Available The right to property is a human right that has to be respected so that if the property of a natural or legal person is taken over, the respective person has to be compensated. The right of a state to control the economic business is one of the rights sustained and exercised by the states on a constant basis. This reflects the inherent sovereignty of a state to control its people, incidents and objects found on its territory. Between these rights, the situation of indirect expropriation appears which has been described in the doctrine as being very abstract and rigid, big lacunae existing. The sense of the indirect expropriation and of the international investors’ protection against the indirect expropriation is very ambiguous. Using different methods specific to scientific analyse of the legal phenomenon (e.g. the logical method, the comparative method, the historical method and the quantitative methods, we consider that through this paper we can reach certain results that could be interesting for any legal practitioner or theoretician, this paper intending to present the most relevant cases that could amount to indirect expropriation.

  15. 49 CFR 30.9 - Citizenship: Direct or indirect control.

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Citizenship: Direct or indirect control. 30.9 Section 30.9 Transportation Office of the Secretary of Transportation DENIAL OF PUBLIC WORKS CONTRACTS TO... title to 50 percent or more of the stock of the contractor or subcontractor is held subject to trust or...

  16. Indirect pulp capping in primary molar using glass ionomer cements

    Murtia Metalita

    2014-12-01

    Full Text Available Background: Indirect pulp capping in primary teeth, however, is more rarely conducted than permanent teeth, since it thought to have low impact and most suggestion is for taking caries lesion aggressively on primary teeth. Purpose: The study was aimed to evaluate the subjective complaint, clinical symptom, and radiographic appearance of indirect pulp capping treatment using glass ionomers cements in primary molar. Methods: Sixteen children in range of age 6 to 8 years old, who visited Clinic of Pediatric Dentistry Universitas Airlangga Dental Hospital, Surabaya Indonesia, were the subject of study. They had one occlusal dental caries on one side of maxillary or mandibular primary molar with the diagnose of pulpitis reversible. The experimental group, had indirect pulp capping treatment with glass ionomer cements (GC Fuji VII®, while the control group, had indirect pulp capping treatment with calcium hydroxide (Metapaste. Each group was filled with GC Fuji IX® as permanent restoration. After one week, one month, and three months later, the observations were made on subjective complaint, clinical symptom, and radiographic appearance. Results: The results showed no subjective complaint such as pain or problem on mastication; no negative clinical symptoms such as pain on palpation, gingivitis or periodontitis, and abnormal tooth mobility; no negative radiographic appearance such as pathological apical radioluscency, internal or external resorbtion, and change of ligament periodontal widthafter the treatment. Conclusion: The study suggested that indirect pulp capping treatment using glass ionomer cement materials on primary teeth might be considered to be the treatment choice.Latar belakang: Indirect pulp capping pada gigi sulung lebih jarang dilakukan dibandingkan gigi permanen, karena dianggap memiliki dampak yang rendah dan sebagian besar menyarankan untuk mengambil lesi karies secara agresif pada gigi sulung. Tujuan: Penelitian ini bertujuan

  17. Radiotherapy of choroidal metastases

    Hoogenhout, J; Gasteren, J J.M. van; Brink, H M.A.; Verbeek, A M; Beex, L V.A.M.

    1989-05-01

    With binocular indirect ophthalmoscopy, fluorescin angiography and ultrasonography 68 choroidal metastases in 52 eyes of 39 patients were diagnosed. The primary tumors were mainly breast cancer (81%) and lung cancer (10%). After radiation treatment the visual acuity improved in 17 eyes (38%), stabilized in 15 eyes (33%), whereas in 13 eyes (29%) deterioration could not be prevented (seven eyes unknown). Regression of the lesions or its accompanying secondary retinal detachment was seen in 78% of the eyes treated. Acute transient side effects of radiation therapy were keratoconjunctivitis (nine patients) and acute glaucoma in one patient. No cataractous changes of the lens were observed in the post radiation period (one to 42 months). Irradiation of choroidal metastases can contribute to improvement of the quality of life with a treatment scheme of 30 Gy in ten daily fractions.

  18. Groupwise information sharing promotes ingroup favoritism in indirect reciprocity.

    Nakamura, Mitsuhiro; Masuda, Naoki

    2012-11-05

    Indirect reciprocity is a mechanism for cooperation in social dilemma situations. In indirect reciprocity, an individual is motivated to help another to acquire a good reputation and receive help from others afterwards. Another aspect of human cooperation is ingroup favoritism, whereby individuals help members in their own group more often than those in other groups. Ingroup favoritism is a puzzle for the theory of cooperation because it is not easily evolutionarily stable. In the context of indirect reciprocity, ingroup favoritism has been shown to be a consequence of employing a double standard when assigning reputations to ingroup and outgroup members. An example of such a double standard is the situation in which helping an ingroup member is regarded as good, whereas the same action toward an outgroup member is regarded as bad. We analyze a computational model of indirect reciprocity in which information sharing is conducted groupwise. In our model, individuals play social dilemma games within and across groups, and the information about their reputations is shared within each group. We show that evolutionarily stable ingroup favoritism emerges even if all the players use the same reputation assignment rule regardless of group (i.e., a single standard). Two reputation assignment rules called simple standing and stern judging yield ingroup favoritism; under these rules, cooperation with (defection against) good individuals is regarded as good (bad) and defection against bad individuals is regarded as good. Stern judging induces much stronger ingroup favoritism than does simple standing. Simple standing and stern judging are evolutionarily stable against each other when groups employing different assignment rules compete and the number of groups is sufficiently large. In addition, we analytically show as a limiting case that homogeneous populations of reciprocators that use reputations are unstable when individuals independently infer reputations of individuals

  19. Trait- and density-mediated indirect interactions initiated by an exotic invasive plant autogenic ecosystem engineer

    Dean E. Pearson

    2010-01-01

    Indirect interactions are important for structuring ecological systems. However, research on indirect effects has been heavily biased toward top-down trophic interactions, and less is known about other indirect-interaction pathways. As autogenic ecosystem engineers, plants can serve as initiators of nontrophic indirect interactions that, like top-down pathways, can...

  20. Indirect evidence for decreased hypothalamic somatostatinergic tone in anorexia nervosa

    Støving, R K; Andersen, M; Flyvbjerg, A

    2002-01-01

    in the central feeding mechanism in anorexia nervosa (AN). Peripheral administration of pyridostigmine (PD) minimizes the release of hypothalamic SRIH. DESIGN: To study the influence of hypothalamic somatostatinergic inhibition on the exaggerated somatotroph responsiveness to GHRH in patients with severe AN, two...... indirectly to greater SRIH withdrawal and greater GHRH release in anorexia nervosa. Moreover, hypothalamic SRIH activity seems to be inversely related to cortisol levels, indirectly supporting the hypothesis that SRIH and CRH neuronal activity are inversely related in anorexia nervosa. Leptin, which...... is believed to act on hypothalamic feeding mechanisms, seems to be positively related to SRIH activity. Finally, the present data demonstrate that the potentiating effect of pyridostigmine in anorexia nervosa is related to body mass index and increases upon weight gain, suggesting that the low...