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Sample records for acuity letter score

  1. A double dissociation of the acuity and crowding limits to letter identification, and the promise of improved visual screening.

    PubMed

    Song, Shuang; Levi, Dennis M; Pelli, Denis G

    2014-05-05

    Here, we systematically explore the size and spacing requirements for identifying a letter among other letters. We measure acuity for flanked and unflanked letters, centrally and peripherally, in normals and amblyopes. We find that acuity, overlap masking, and crowding each demand a minimum size or spacing for readable text. Just measuring flanked and unflanked acuity is enough for our proposed model to predict the observer's threshold size and spacing for letters at any eccentricity. We also find that amblyopia in adults retains the character of the childhood condition that caused it. Amblyopia is a developmental neural deficit that can occur as a result of either strabismus or anisometropia in childhood. Peripheral viewing during childhood due to strabismus results in amblyopia that is crowding limited, like peripheral vision. Optical blur of one eye during childhood due to anisometropia without strabismus results in amblyopia that is acuity limited, like blurred vision. Furthermore, we find that the spacing:acuity ratio of flanked and unflanked acuity can distinguish strabismic amblyopia from purely anisometropic amblyopia in nearly perfect agreement with lack of stereopsis. A scatter diagram of threshold spacing versus acuity, one point per patient, for several diagnostic groups, reveals the diagnostic power of flanked acuity testing. These results and two demonstrations indicate that the sensitivity of visual screening tests can be improved by using flankers that are more tightly spaced and letter like. Finally, in concert with Strappini, Pelli, Di Pace, and Martelli (submitted), we jointly report a double dissociation between acuity and crowding. Two clinical conditions-anisometropic amblyopia and apperceptive agnosia-each selectively impair either acuity A or the spacing:acuity ratio S/A, not both. Furthermore, when we specifically estimate crowding, we find a double dissociation between acuity and crowding. Models of human object recognition will need to

  2. A double dissociation of the acuity and crowding limits to letter identification, and the promise of improved visual screening

    PubMed Central

    Song, Shuang; Levi, Dennis M.; Pelli, Denis G.

    2014-01-01

    Here, we systematically explore the size and spacing requirements for identifying a letter among other letters. We measure acuity for flanked and unflanked letters, centrally and peripherally, in normals and amblyopes. We find that acuity, overlap masking, and crowding each demand a minimum size or spacing for readable text. Just measuring flanked and unflanked acuity is enough for our proposed model to predict the observer's threshold size and spacing for letters at any eccentricity. We also find that amblyopia in adults retains the character of the childhood condition that caused it. Amblyopia is a developmental neural deficit that can occur as a result of either strabismus or anisometropia in childhood. Peripheral viewing during childhood due to strabismus results in amblyopia that is crowding limited, like peripheral vision. Optical blur of one eye during childhood due to anisometropia without strabismus results in amblyopia that is acuity limited, like blurred vision. Furthermore, we find that the spacing:acuity ratio of flanked and unflanked acuity can distinguish strabismic amblyopia from purely anisometropic amblyopia in nearly perfect agreement with lack of stereopsis. A scatter diagram of threshold spacing versus acuity, one point per patient, for several diagnostic groups, reveals the diagnostic power of flanked acuity testing. These results and two demonstrations indicate that the sensitivity of visual screening tests can be improved by using flankers that are more tightly spaced and letter like. Finally, in concert with Strappini, Pelli, Di Pace, and Martelli (submitted), we jointly report a double dissociation between acuity and crowding. Two clinical conditions—anisometropic amblyopia and apperceptive agnosia—each selectively impair either acuity A or the spacing:acuity ratio S/A, not both. Furthermore, when we specifically estimate crowding, we find a double dissociation between acuity and crowding. Models of human object recognition will need

  3. Predicting individual contrast sensitivity functions from acuity and letter contrast sensitivity measurements

    PubMed Central

    Thurman, Steven M.; Davey, Pinakin Gunvant; McCray, Kaydee Lynn; Paronian, Violeta; Seitz, Aaron R.

    2016-01-01

    Contrast sensitivity (CS) is widely used as a measure of visual function in both basic research and clinical evaluation. There is conflicting evidence on the extent to which measuring the full contrast sensitivity function (CSF) offers more functionally relevant information than a single measurement from an optotype CS test, such as the Pelli–Robson chart. Here we examine the relationship between functional CSF parameters and other measures of visual function, and establish a framework for predicting individual CSFs with effectively a zero-parameter model that shifts a standard-shaped template CSF horizontally and vertically according to independent measurements of high contrast acuity and letter CS, respectively. This method was evaluated for three different CSF tests: a chart test (CSV-1000), a computerized sine-wave test (M&S Sine Test), and a recently developed adaptive test (quick CSF). Subjects were 43 individuals with healthy vision or impairment too mild to be considered low vision (acuity range of −0.3 to 0.34 logMAR). While each test demands a slightly different normative template, results show that individual subject CSFs can be predicted with roughly the same precision as test–retest repeatability, confirming that individuals predominantly differ in terms of peak CS and peak spatial frequency. In fact, these parameters were sufficiently related to empirical measurements of acuity and letter CS to permit accurate estimation of the entire CSF of any individual with a deterministic model (zero free parameters). These results demonstrate that in many cases, measuring the full CSF may provide little additional information beyond letter acuity and contrast sensitivity. PMID:28006065

  4. Learning to Identify Near-Acuity Letters, either with or without Flankers, Results in Improved Letter Size and Spacing Limits in Adults with Amblyopia

    PubMed Central

    Chung, Susana T. L.; Li, Roger W.; Levi, Dennis M.

    2012-01-01

    Amblyopia is a developmental abnormality that results in deficits for a wide range of visual tasks, most notably, the reduced ability to see fine details, the loss in contrast sensitivity especially for small objects and the difficulty in seeing objects in clutter (crowding). The primary goal of this study was to evaluate whether crowding can be ameliorated in adults with amblyopia through perceptual learning using a flanked letter identification task that was designed to reduce crowding, and if so, whether the improvements transfer to untrained visual functions: visual acuity, contrast sensitivity and the size of visual span (the amount of information obtained in one fixation). To evaluate whether the improvements following this training task were specific to training with flankers, we also trained another group of adult observers with amblyopia using a single letter identification task that was designed to improve letter contrast sensitivity, not crowding. Following 10,000 trials of training, both groups of observers showed improvements in the respective training task. The improvements generalized to improved visual acuity, letter contrast sensitivity, size of the visual span, and reduced crowding. The magnitude of the improvement for each of these measurements was similar in the two training groups. Perceptual learning regimens aimed at reducing crowding or improving letter contrast sensitivity are both effective in improving visual acuity, contrast sensitivity for near-acuity objects and reducing the crowding effect, and could be useful as a clinical treatment for amblyopia. PMID:22558234

  5. Early Quick Acuity Score Provides More Complete Data on Emergency Department Walkouts

    PubMed Central

    Lovett, Paris B.; Kahn, J. Akiva; Greene, Stuart E.; Bloch, Matthew A.; Brandt, Daniel R.; Minckler, Michael R.

    2014-01-01

    Introduction Many prior studies have compared the acuity of Emergency Department (ED) patients who have Left Without Being Seen (LWBS) against non-LWBS patients. A weakness in these studies is that patients may walk out prior to the assignment of a triage score, biasing comparisons. We report an operational change whereby acuity was assessed immediately upon patient arrival. We hypothesized more patients would receive acuity scores with EQAS. We also sought to compare LWBS and non-LWBS patient characteristics with reduced bias. Methods Setting: urban, academic medical center. Retrospective cohort study, electronic chart review, collecting data on all ED patients presenting between 4/1/2010 and 10/31/2011 (“Traditional Acuity Score” period, TAS) and from 11/1/2011 to 3/31/2012 (“Early Quick Acuity Score” period, EQAS). We recorded disposition (LWBS versus non-LWBS), acuity and demographics. For each subject during the EQAS period, we calculated how many prior ED visits and how many prior walkouts the subject had had during the TAS period. Results Acuity was recorded in 92,275 of 94,526 patients (97.6%) for TAS period, and 25,577 of 25,760 patients (99.3%) for EQAS period, a difference of 1.7% (1.5%, 1.8%). LWBS patients had acuity scores recorded in 5,180 of 7,040 cases (73.6%) during TAS period, compared with 897 of 1,010 cases (88.8%) during the EQAS period, a difference of 15.2% (14.8%, 15.7%). LWBS were more likely than non-LWBS to be male, were younger and had lower acuity scores. LWBS averaged 5.3 prior ED visits compared with 2.8 by non-LWBS, a difference of 2.5 (1.5, 3.5). LWBS averaged 1.3 prior ED walkouts compared with 0.2 among non-LWBS, a difference of 1.1 (0.8, 1.3). Conclusions EQAS resulted in a higher proportion of patients receiving acuity scores, particularly among LWBS. This offers more complete data when comparing LWBS and non-LWBS patient characteristics. The comparison reinforced findings from prior studies. PMID:24465699

  6. Developmental Changes during Childhood in Single-Letter Acuity and Its Crowding by Surrounding Contours

    ERIC Educational Resources Information Center

    Jeon, Seong Taek; Hamid, Joshua; Maurer, Daphne; Lewis, Terri L.

    2010-01-01

    Crowding refers to impaired target recognition caused by surrounding contours. We investigated the development of crowding in central vision by comparing single-letter and crowding thresholds in groups of 5-year-olds, 8-year-olds, 11-year-olds, and adults. The task was to discriminate the orientation of a Sloan letter E. Single-letter thresholds,…

  7. Relationship of Medical Students' Admission Interview Scores to Their Dean's Letter Ratings.

    ERIC Educational Resources Information Center

    Hall, Frances R.; And Others

    1992-01-01

    A study found that the admission interview scores for 62 Dartmouth Medical School (New Hampshire) applicants correlated positively with dean's letter ratings given 4 years later and that interview scores were better predictors of ratings than were total Medical College Admission Test scores or science grade point averages. (Author/MSE)

  8. Preschool visual acuity screening tests.

    PubMed Central

    Friendly, D S

    1978-01-01

    The purpose of the study was to evaluate the relative merits of two screening tests used for visual acuity assessment of preschool children. The tests that were compared were the Good-Lite Company versions of the E-Test and of the STYCAR (Screening Test for Young Children and Retardates). The former is the most popular method for evaluating central acuity in young children in this nation; the STYCAR is a relatively new letter-matching-test developed in England, where it is widely employed. The E-Test poses left-right orientation problems which are eliminated by the symmetrical letters H, T, O and V utilized in the Letter-Matching-Test. Both visual acuity tests were administered on two separate occasions by personnel from the Prevention of Blindness Society of Metropolitan Washington to 633 preschool children in Washington, D.C. By random selection, 150 of the children received the E-Test at both sessions, 162 children received the Letter-Matching-Test at both sessions, 160 chilt athe the second session, and 161 children received the Letter-Matching-Test at the first session and the E-Test at the second session. The author medically examined the eyes of 408 of the 633 children without knowledge of which test had been initially administered. Statistical analysis of the data obtained from the study indicated that the Letter-Matching-Test was significantly better in terms of testability rates, group and individual instruction time, and performance time. The E-Test was more reliable in terms of test-retest acuity scores and was also more valid in terms of agreement between pass-fail results obtained at the first screening session and two levels of pass-fail refraction criteria. Images FIGURE 4 FIGURE 5 FIGURE 7 A FIGURE 7 B FIGURE 9 A FIGURE 9 B PMID:754379

  9. Changes in the clinical measurement of visual acuity

    NASA Astrophysics Data System (ADS)

    Bailey, I. L.; Jackson, A. J.

    2016-11-01

    In 1862, Hermann Snellen introduced his letter chart for the clinical measurement of visual acuity. His chart presented letters,or optotypes, arranged in a progressively diminishing size sequence, and the visual acuity was determined by the smallest letters that could read at a specified distance. Numerous modifications of the design of the optotypes, the progression of size and the chart layout were suggested, and in 1976, Bailey and Lovie published a set of design principles that made the visual task the same at all size levels, so that size become the only significant variable. This required the same number of letters at each size level, fixed spacing ratios and a logarithmic progression of size. This facilitates more precise quantification of visual acuity by giving credit for every letter read correctly, and this gives clinicians tighter confidence limits for determining changes or differences in visual acuity. However, optotype choices, and associated spacing arrangements can have significant effects on visual acuity scores as can viewing conditions and testing protocols. Computer based visual acuity tests are becoming more commonplace, there will be more variety in test charts and procedures which will create some problems for making comparisons between tests.

  10. Visual acuity measured with luminance-modulated and contrast-modulated noise letter stimuli in young adults and adults above 50 years old

    PubMed Central

    Woi, Pui Juan; Kaur, Sharanjeet; Waugh, Sarah J.; Hairol, Mohd Izzuddin

    2016-01-01

    The human visual system is sensitive in detecting objects that have different luminance level from their background, known as first-order or luminance-modulated (LM) stimuli. We are also able to detect objects that have the same mean luminance as their background, only differing in contrast (or other attributes). Such objects are known as second-order or contrast-modulated (CM), stimuli. CM stimuli are thought to be processed in higher visual areas compared to LM stimuli, and may be more susceptible to ageing. We compared visual acuities (VA) of five healthy older adults (54.0±1.83 years old) and five healthy younger adults (25.4±1.29 years old) with LM and CM letters under monocular and binocular viewing. For monocular viewing, age had no effect on VA [F(1, 8)= 2.50, p> 0.05]. However, there was a significant main effect of age on VA under binocular viewing [F(1, 8)= 5.67, p< 0.05].  Binocular VA with CM letters in younger adults was approximately two lines better than that in older adults. For LM, binocular summation ratios were similar for older (1.16±0.21) and younger (1.15±0.06) adults. For CM, younger adults had higher binocular summation ratio (1.39±0.08) compared to older adults (1.12±0.09). Binocular viewing improved VA with LM letters for both groups similarly. However, in older adults, binocular viewing did not improve VA with CM letters as much as in younger adults. This could reflect a decline of higher visual areas due to ageing process, most likely higher than V1, which may be missed if measured with luminance-based stimuli alone. PMID:28184281

  11. Visual acuity measured with luminance-modulated and contrast-modulated noise letter stimuli in young adults and adults above 50 years old.

    PubMed

    Woi, Pui Juan; Kaur, Sharanjeet; Waugh, Sarah J; Hairol, Mohd Izzuddin

    2016-01-01

    The human visual system is sensitive in detecting objects that have different luminance level from their background, known as first-order or luminance-modulated (LM) stimuli. We are also able to detect objects that have the same mean luminance as their background, only differing in contrast (or other attributes). Such objects are known as second-order or contrast-modulated (CM), stimuli. CM stimuli are thought to be processed in higher visual areas compared to LM stimuli, and may be more susceptible to ageing. We compared visual acuities (VA) of five healthy older adults (54.0±1.83 years old) and five healthy younger adults (25.4±1.29 years old) with LM and CM letters under monocular and binocular viewing. For monocular viewing, age had no effect on VA [F(1, 8)= 2.50, p> 0.05]. However, there was a significant main effect of age on VA under binocular viewing [F(1, 8)= 5.67, p< 0.05].  Binocular VA with CM letters in younger adults was approximately two lines better than that in older adults. For LM, binocular summation ratios were similar for older (1.16±0.21) and younger (1.15±0.06) adults. For CM, younger adults had higher binocular summation ratio (1.39±0.08) compared to older adults (1.12±0.09). Binocular viewing improved VA with LM letters for both groups similarly. However, in older adults, binocular viewing did not improve VA with CM letters as much as in younger adults. This could reflect a decline of higher visual areas due to ageing process, most likely higher than V1, which may be missed if measured with luminance-based stimuli alone.

  12. Do picture-based charts overestimate visual acuity? Comparison of Kay Pictures, Lea Symbols, HOTV and Keeler logMAR charts with Sloan letters in adults and children

    PubMed Central

    Simkin, Samantha K.; Thomson, Melissa

    2017-01-01

    Purpose Children may be tested with a variety of visual acuity (VA) charts during their ophthalmic care and differences between charts can complicate the interpretation of VA measurements. This study compared VA measurements across four pediatric charts with Sloan letters and identified chart design features that contributed to inter-chart differences in VA. Methods VA was determined for right eyes of 25 adults and 17 children (4–9 years of age) using Crowded Kay Pictures, Crowded linear Lea Symbols, Crowded Keeler logMAR, Crowded HOTV and Early Treatment of Diabetic Retinopathy Study (ETDRS) charts in focused and defocused (+1.00 DS optical blur) conditions. In a separate group of 25 adults, we compared the VA from individual Kay Picture optotypes with uncrowded Landolt C VA measurements. Results Crowded Kay Pictures generated significantly better VA measurements than all other charts in both adults and children (p < 0.001; 0.15 to 0.30 logMAR). No significant differences were found between other charts in adult participants; children achieved significantly poorer VA measurements on the ETDRS chart compared with pediatric acuity tests. All Kay Pictures optotypes produced better VA (p < 0.001), varying from -0.38 ± 0.13 logMAR (apple) to -0.57 ± 0.10 logMAR (duck), than the reference Landolt C task (mean VA -0.19 ± 0.08 logMAR). Conclusion Kay Pictures over-estimated VA in all participants. Variability between Kay Pictures optotypes suggests that shape cues aid in optotype determination. Other pediatric charts offer more comparable VA measures and should be used for children likely to progress to letter charts. PMID:28152076

  13. Visual acuity and test performance.

    PubMed

    Heron, E; Zytkoskee, A

    1981-02-01

    Evaluation of scholastic achievement (American College Testing Service) test scores confirms previous reports that persons with poor visual acuity perform better on these tests than individuals with normal or superior acuity.

  14. High and Low Contrast Visual Acuity Are Not Affected in Amyotrophic Lateral Sclerosis.

    PubMed

    Moss, Heather E; Samelson, Monica; Mohan, Girish; Jiang, Qin Li

    2016-01-01

    The afferent visual system may be affected by neuro-degeneration in amyotrophic lateral sclerosis (ALS) based on observations of visual function impairment and retinal inclusions on histopathology in ALS patients. To test the hypothesis that visual acuity is impaired in ALS, we compared three measures of visual acuity in ALS patients (n = 25) attending a multidisciplinary ALS clinic and age matched control subjects (n = 25). Bilateral monocular and binocular visual acuities were assessed using high contrast (black letters on white background) and low contrast (2.5%, 1.25% grey letters on white background) visual acuity charts under controlled lighting conditions following refraction. Binocular summation was calculated as the difference between binocular and best monocular acuity scores. There were no associations between binocular or monocular high contrast visual acuity or low contrast visual acuity and amyotrophic lateral sclerosis diagnosis (generalized estimating equation models accounting for age). Binocular summation was similar in both amyotrophic lateral sclerosis and control subjects. There was a small magnitude association between increased duration of ALS symptoms and reduced 1.25% low contrast visual acuity. This study does not confirm prior observations of impaired visual acuity in patients with amyotrophic lateral sclerosis and does not support this particular measure of visual function for use in broad scale assessment of visual pathway involvement in ALS patients.

  15. High and Low Contrast Visual Acuity Are Not Affected in Amyotrophic Lateral Sclerosis

    PubMed Central

    Samelson, Monica; Mohan, Girish; Jiang, Qin Li

    2016-01-01

    The afferent visual system may be affected by neuro-degeneration in amyotrophic lateral sclerosis (ALS) based on observations of visual function impairment and retinal inclusions on histopathology in ALS patients. To test the hypothesis that visual acuity is impaired in ALS, we compared three measures of visual acuity in ALS patients (n = 25) attending a multidisciplinary ALS clinic and age matched control subjects (n = 25). Bilateral monocular and binocular visual acuities were assessed using high contrast (black letters on white background) and low contrast (2.5%, 1.25% grey letters on white background) visual acuity charts under controlled lighting conditions following refraction. Binocular summation was calculated as the difference between binocular and best monocular acuity scores. There were no associations between binocular or monocular high contrast visual acuity or low contrast visual acuity and amyotrophic lateral sclerosis diagnosis (generalized estimating equation models accounting for age). Binocular summation was similar in both amyotrophic lateral sclerosis and control subjects. There was a small magnitude association between increased duration of ALS symptoms and reduced 1.25% low contrast visual acuity. This study does not confirm prior observations of impaired visual acuity in patients with amyotrophic lateral sclerosis and does not support this particular measure of visual function for use in broad scale assessment of visual pathway involvement in ALS patients. PMID:28033389

  16. Letters

    NASA Astrophysics Data System (ADS)

    2001-01-01

    The Editor welcomes letters, by e-mail to ped@iop.org or by post to Dirac House, Temple Back, Bristol BS1 6BE, UK. Contents: Maths for physics? Help! Fire! Energy and mass Maths for physics? As a maths graduate working as a university research associate I should be well qualified to support my daughter, who has just started AS-level physics, with the maths she needs for the course. There seems to be little integration between the maths and physics departments, so that maths needed for physics has not yet been covered in maths lessons. This is a problem I remember from my own school days, but the shorter timescale and modular nature of the AS and A2 levels means that it is essential that this mismatch of knowledge is resolved now. I would like to know whether physics teachers in the UK have encountered this problem and whether there is a deficiency in the maths syllabus in relation to the requirements of the AS and A2 levels in Physics or whether this is a problem peculiar to my daughter's school. Eleanor Parent of A-level student, Sheffield, UK Help! Fire! Is there a crisis in physics education? Is physics didactics coming to an end? Yes and no. Being a delegate from Norway at the on-going conference Physics on Stage (6-10 November 2000) at CERN in Geneva, I have had the opportunity to discuss this with people from all over Europe. Yes, there is a crisis. (Look at the proceedings for details on this.) I'd like to take a broader look at this situation. Like Hari Seldon in Isaac Asimov's Foundation Trilogy, I believe that there is nothing like a real crisis to get things going... Famous is the quote from the American Patent Office around 1890: 'Everything has been invented that could be invented'. Fortunately, this spurred action. The Michelson and Morley experiment heralded a most exciting period for physics. Just a cosmic blink later we put a person on the Moon. Coming back to the crisis - I am certain that in the near future we will see an interesting development

  17. Letters

    NASA Astrophysics Data System (ADS)

    2001-07-01

    The Editor welcomes letters, by e-mail to ped@iop.org or by post to Dirac House, Temple Back, Bristol BS1 6BE, UK. Contents: Alternative view of education in Zambia Pedantry or compromise Alternative view of education in Zambia I have just read the 'On the Map' report of the International School of Lusaka with very mixed feelings (Physics Education, March 2001). I have recently spent some time in Zambia, in Lusaka, and share Sue Pears' love for the country and the Zambians. The ISL is indeed a good, prestigious school, similar to International Schools in many other countries. But, as in most other developing countries, there is enormous variation between the different types of schooling, and the ISL is at one end of the spectrum. Most schools in Zambia are less favoured. Zambia is a wonderful, beautiful country full of the most friendly and resourceful people I know. It is also a very poor country. It is a country of enormous contrasts and its schools reflect that variation. It has a tiny, affluent 'middle' class of professionals, politicians, businessmen, employees of international businesses and NGOs—nearly all paid from overseas budgets. It has an enormous majority of poor folk, cheerfully living in very basic conditions but sharing their lives in extended families without complaint. The government is virtually bankrupt, and consequently those paid by the government—teachers, police, nurses etc—get a pittance. The wage for a teacher in a typical school is #20 per month (compared to a typical teacher in the UK who gets 100 times more, about #2000 per month). The GNP in Zambia is about 1 per day per person, and this has to pay for all the schools, hospitals, police, and the civic infrastructure that we take so much for granted (the GNP in UK is about 60 per day per person). Consequently most state schools do not have resources; they have a classroom and a teacher but little else. What resources the school has will be paid for by the school fees that every

  18. Letters

    NASA Astrophysics Data System (ADS)

    2001-03-01

    The Editor welcomes letters, by e-mail to ped@iop.org or by post to Dirac House, Temple Back, Bristol BS1 6BE Contents: Force on a pendulum Sound slows down Bond is back Force on a pendulum The simple pendulum has been used by several educationalists for investigating the patterns of thinking among students and their observations that Aristotelian thinking persists among students at college level. I had also considered the simple pendulum in my 1985 letter in Physics Today [1], so I was interested to read the test given by Lenka Czudková and Jana Musilová [2]. When students were asked to draw net forces acting on the particle at various positions, 31.9% of students believed that the net force was tangential to the particle's path the whole time. To me this is no surprise because in our derivation of the equation for the period of a simple pendulum we assume that the unbalanced sine component provides the restoring force for the harmonic motion of the bob. Of course, Czudková and Musilová's question asked students for the net force on the particle, not the component. The student's answer fits well with the logic of the equilibrium of forces and the parallelogram law. Lastly, let me bring out the similarity between the student's answer and the thinking of George Gamow. He used to call positrons 'donkey' electrons because of their displacement against the applied force, before Paul Dirac termed them positrons. Victor Weisskeptf told me this anecdote in a letter in May 1982. References [1] Sathe D 1985 Phys. Today 38 144 [2] Czudková L and Musilová J 2000 Phys. Educ. 35 428 Dileep V Sathe Dadawala Jr College, Pune, India Sound slows down Without wanting to stir up more trouble amongst the already muddy waters of Physics teaching, consider how many times you have heard (or, more worryingly, read) this: 'Sound waves travel faster in a denser material' But...The velocity of simple longitudinal waves in a bulk medium is given by v = (K/ρ)1/2 where K is

  19. Letters

    NASA Astrophysics Data System (ADS)

    2001-09-01

    The Editor welcomes letters, by e-mail to ped@iop.org or by post to Dirac House, Temple Back, Bristol BS1 6BE, UK. Contents: M-set as metaphor The abuse of algebra M-set as metaphor 'To see a World in a Grain of Sand And a Heaven in a Wild Flower Hold Infinity in the palm of your hand And Eternity in an hour' William Blake's implied relativity of spatial and temporal scales is intriguing and, given the durability of this worlds-within-worlds concept (he wrote in 1803) in art, literature and science, the blurring of distinctions between the very large and the very small must strike some kind of harmonious chord in the human mind. Could this concept apply to the physical world? To be honest, we cannot be absolutely sure. Most cosmological thinking still retains the usual notions of a finite universe and an absolute size scale extending from smallest to largest objects. In the boundless realm of mathematics, however, the story is quite different. The M-set was discovered by the French mathematician Benoit Mandelbrot in 1980, created by just a few simple lines of computer code that are repeated recursively. As in Blake's poem, this 'world' has no bottom we have an almost palpable archetype for the concept of infinity. I would use the word 'tangible', but one of the defining features of the M-set is that nowhere in the labyrinth can one find a surface smooth enough for a tangent. Upon magnification even surfaces that appeared to be smooth explode with quills and scrolls and lightning bolts and spiral staircases. And there is something more, something truly sublime. Observe a small patch with unlimited magnifying power and, as you observe the M-set on ever-smaller scales, down through literally endless layers of ornate structure, you occasionally come upon a rapidly expanding cortex of dazzling colour with a small black structure at its centre. The black spot appears to be the M-set itself! There is no end to the hierarchy, no bottom-most level, just endless recursive

  20. Letters

    NASA Astrophysics Data System (ADS)

    2001-05-01

    The Editor welcomes letters, by e-mail to ped@iop.org or by post to Dirac House, Temple Back, Bristol BS1 6BE, UK. Contents: Quantum uncertainties Reflections in a plastic box A brief history of quantum physics Correction Grammar and gender Quantum uncertainties Whilst I enjoyed Gesche Pospiech's article ('Uncertainty and complementarity: the heart of quantum physics' 2000 Phys. Educ. 35 393 9) I would like to expand on two comments he makes. Firstly the author claims that QM is linear, and a consequence of this is that any two superimposed states form an admissible third state. This is rather too sweeping, as it is true only for degenerate states. Otherwise quantum mechanics would allow a continuum of energies between states by a simple admixture of levels. The proof of this statement is trivial. For a Hamiltonian H and two orthogonal wavefunctions, ψ1 and ψ2 with energies E1 and E2 then (ψ1 + ψ2) is not an eigenfunction of that Hamiltonian as H(ψ1 + ψ2) = E1ψ1 + E2ψ2 ≠ E(ψ1 + ψ2) for any value of E, unless E1 = E2. Secondly Pospiech states that quantum objects show wave- or particle-like behaviour, depending on the measuring apparatus, and that occasionally experiments (such as Taylor's) reveal both. I would contest the validity of this type of thinking. All experiments on quantum objects reveal both types of behaviour—even ones which simply show straight line motion of photons. What is important, in addition, is our interpretation of the results. It takes an understanding of QED, for example, to see that an experiment which otherwise shows particle behaviour is, in fact, showing quantum behaviour. More contentiously though I would suggest that detection apparatus is incapable of detecting anything other than particles. Wave-like behaviour is revealed only by an analysis of the paths the particle could have taken. In other words, the interference of continuous fields sometimes predicts the same results when the detection is averaged over many events

  1. Factors Affecting Crowded Acuity: Eccentricity and Contrast

    PubMed Central

    Coates, Daniel R.; Chin, Jeremy M.; Chung, Susana T. L.

    2013-01-01

    Purpose Acuity measurement is a fundamental method to assess visual performance in the clinic. Little is known about how acuity measured in the presence of neighboring letters, as in the case of letter charts, changes with contrast and with non-foveal viewing. This information is crucial for acuity measurement using low-contrast charts and when patients cannot use their fovea. In this study, we evaluated how optotype acuity, with and without flankers, is affected by contrast and eccentricity. Methods Five young adults with normal vision identified the orientation of a Tumbling-E alone or in the presence of four flanking Tumbling-Es. Edge-to-edge letter spacing ranged from 1 to 20 bar widths. Stimuli were presented on a white background for 150 ms with Weber contrast ranging from −2.5% to −99%. Flankers had the same size and contrast as the target. Testings were performed at the fovea, 3, 5 and 10 degrees in the inferior visual field. Results When plotted as a function of letter spacing, acuity remains unaffected by the presence of flankers until the flankers are within the critical spacing, which averages an edge-to-edge spacing of 4.4 bar widths at the fovea, and approximately 16 bar widths at all three eccentricities. Critical spacing decreases with a reduction in contrast. When plotted as a function of contrast, acuity only worsens when the contrast falls below approximately 24% at the fovea and 17% in the periphery, for flanked and unflanked conditions alike. Conclusions The letter spacing on conventional letter charts exceeds the critical spacing for acuity measurement at the fovea, at all contrast levels. Thus these charts are appropriate for assessing foveal acuity. In the periphery, the critical spacing is larger than the letter spacing on conventional charts. Consequently, these charts may underestimate the acuity measured in the periphery due to the effects of crowding. PMID:23770657

  2. 21 CFR 886.1150 - Visual acuity chart.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Visual acuity chart. 886.1150 Section 886.1150...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1150 Visual acuity chart. (a) Identification. A visual acuity chart is a device that is a chart, such as a Snellen chart with block letters...

  3. First quality score for referral letters in gastroenterology—a validation study

    PubMed Central

    Eskeland, Sigrun Losada; Brunborg, Cathrine; Seip, Birgitte; Wiencke, Kristine; Hovde, Øistein; Owen, Tanja; Skogestad, Erik; Huppertz-Hauss, Gert; Halvorsen, Fred-Arne; Garborg, Kjetil; Aabakken, Lars; de Lange, Thomas

    2016-01-01

    Objective To create and validate an objective and reliable score to assess referral quality in gastroenterology. Design An observational multicentre study. Setting and participants 25 gastroenterologists participated in selecting variables for a Thirty Point Score (TPS) for quality assessment of referrals to gastroenterology specialist healthcare for 9 common indications. From May to September 2014, 7 hospitals from the South-Eastern Norway Regional Health Authority participated in collecting and scoring 327 referrals to a gastroenterologist. Main outcome measure Correlation between the TPS and a visual analogue scale (VAS) for referral quality. Results The 327 referrals had an average TPS of 13.2 (range 1–25) and an average VAS of 4.7 (range 0.2–9.5). The reliability of the score was excellent, with an intra-rater intraclass correlation coefficient (ICC) of 0.87 and inter-rater ICC of 0.91. The overall correlation between the TPS and the VAS was moderate (r=0.42), and ranged from fair to substantial for the various indications. Mean agreement was good (ICC=0.47, 95% CI (0.34 to 0.57)), ranging from poor to good. Conclusions The TPS is reliable, objective and shows good agreement with the subjective VAS. The score may be a useful tool for assessing referral quality in gastroenterology, particularly important when evaluating the effect of interventions to improve referral quality. PMID:27855107

  4. State-Trait Decomposition of Name Letter Test Scores and Relationships With Global Self-Esteem.

    PubMed

    Perinelli, Enrico; Alessandri, Guido; Donnellan, M Brent; Łaguna, Mariola

    2017-01-09

    The Name Letter Test (NLT) assesses the degree that participants show a preference for an individual's own initials. The NLT was often thought to measure implicit self-esteem, but recent literature reviews do not equivocally support this hypothesis. Several authors have argued that the NLT is most strongly associated with the state component of self-esteem. The current research uses a modified STARTS model to (a) estimate the percentage of stable and transient components of the NLT and (b) estimate the covariances between stable/transient components of the NLT and stable/transient components of self-esteem and positive and negative affect. Two longitudinal studies were conducted with different time lags: In Study 1, participants were assessed daily for 7 consecutive days, whereas in Study 2, participants were assessed weekly for 8 consecutive weeks. Participants also completed a battery of questionnaires including global self-esteem, positive affect, and negative affect. In both studies, the NLT showed (a) high stability across time, (b) a high percentage of stable variance, (c) no significant covariance with stable and transient factors for global self-esteem, and (d) a different pattern of correlations with stable and transient factors of affect than global self-esteem. Collectively, these results further undermine the claim that the NLT is a valid measure of implicit self-esteem. Future work is needed to identify theoretically grounded correlates of the NLT. (PsycINFO Database Record

  5. Metamorphopsia and letter recognition.

    PubMed

    Wiecek, Emily; Dakin, Steven C; Bex, Peter

    2014-12-01

    Acuity is the most commonly used measure of visual function, and reductions in acuity are associated with most eye diseases. Metamorphopsia--a perceived distortion of visual space--is another common symptom of visual impairment and is currently assessed qualitatively using Amsler (1953) charts. In order to quantify the impact of metamorphopsia on acuity, we measured the effect of physical spatial distortion on letter recognition. Following earlier work showing that letter recognition is tuned to specific spatial frequency (SF) channels, we hypothesized that the effect of distortion might depend on the spatial scale of visual distortion just as it depends on the spatial scale of masking noise. Six normally sighted observers completed a 26 alternate forced choice (AFC) Sloan letter identification task at five different viewing distances, and the letters underwent different levels of spatial distortion. Distortion was controlled using spatially band-pass filtered noise that spatially remapped pixel locations. Noise was varied over five spatial frequencies and five magnitudes. Performance was modeled with logistic regression and worsened linearly with increasing distortion magnitude and decreasing letter size. We found that retinal SF affects distortion at midrange frequencies and can be explained with the tuning of a basic contrast sensitivity function, while object-centered distortion SF follows a similar pattern of letter object recognition sensitivity and is tuned to approximately three cycles per letter (CPL). The interaction between letter size and distortion makes acuity an unreliable outcome for metamorphopsia assessment.

  6. Metamorphopsia and letter recognition

    PubMed Central

    Wiecek, Emily; Dakin, Steven C.; Bex, Peter

    2014-01-01

    Acuity is the most commonly used measure of visual function, and reductions in acuity are associated with most eye diseases. Metamorphopsia—a perceived distortion of visual space—is another common symptom of visual impairment and is currently assessed qualitatively using Amsler (1953) charts. In order to quantify the impact of metamorphopsia on acuity, we measured the effect of physical spatial distortion on letter recognition. Following earlier work showing that letter recognition is tuned to specific spatial frequency (SF) channels, we hypothesized that the effect of distortion might depend on the spatial scale of visual distortion just as it depends on the spatial scale of masking noise. Six normally sighted observers completed a 26 alternate forced choice (AFC) Sloan letter identification task at five different viewing distances, and the letters underwent different levels of spatial distortion. Distortion was controlled using spatially band-pass filtered noise that spatially remapped pixel locations. Noise was varied over five spatial frequencies and five magnitudes. Performance was modeled with logistic regression and worsened linearly with increasing distortion magnitude and decreasing letter size. We found that retinal SF affects distortion at midrange frequencies and can be explained with the tuning of a basic contrast sensitivity function, while object-centered distortion SF follows a similar pattern of letter object recognition sensitivity and is tuned to approximately three cycles per letter (CPL). The interaction between letter size and distortion makes acuity an unreliable outcome for metamorphopsia assessment. PMID:25453116

  7. Visual Vestibular Interaction in the Dynamic Visual Acuity Test during Voluntary Head Rotation

    NASA Technical Reports Server (NTRS)

    Lee, Moo Hoon; Durnford, Simon; Crowley, John; Rupert, Angus

    1996-01-01

    Although intact vestibular function is essential in maintaining spatial orientation, no good screening tests of vestibular function are available to the aviation community. High frequency voluntary head rotation was selected as a vestibular stimulus to isolate the vestibulo-ocular reflex (VOR) from visual influence. A dynamic visual acuity test that incorporates voluntary head rotation was evaluated as a potential vestibular function screening tool. Twenty-seven normal subjects performed voluntary sinusoidal head rotation at frequencies from 0.7-4.0 Hz under three different visual conditions: visually-enhanced VOR, normal VOR, and visually suppressed VOR. Standardized Baily-Lovie chart letters were presented on a computer monitor in front of the subject, who then was asked to read the letters while rotating his head horizontally. The electro-oculogram and dynamic visual acuity score were recorded and analyzed. There were no significant differences in gain or phase shift among three visual conditions in the frequency range of 2.8 to 4.0 Hz. The dynamic visual acuity score shifted less than 0.3 logMAR at frequencies under 2.0 Hz. The dynamic visual acuity test at frequencies a round 2.0 Hz can be recommended for evaluating vestibular function.

  8. Visual acuity test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003396.htm Visual acuity test To use the sharing features on this page, please enable JavaScript. The visual acuity test is used to determine the smallest ...

  9. Could test length or order affect scores on letter number sequencing of the WAIS-III and WMS-III? Ruling out effects of fatigue.

    PubMed

    Tulsky, D S; Zhu, J

    2000-11-01

    The Letter Number Sequencing subtest of the WAIS-III and WMS-III was administered at the end of the standardization edition of the WMS-III. It was not administered as part of the WAIS-III standardization battery. Nevertheless, the subtest was included in the published version of the WAIS-III. This study examines differences between examinees administered the Letter Number Sequencing subtest at three different times during a psychological battery: (1) as part of the published battery, (2) as part of the WMS-III when the WMS-III was administered as the first test in a sequence, and (3) as part of the WMS-III standardization when the WAIS-III was administered immediately preceding the WMS-III. The participants were 372 examinees ( n = 124 in each condition) who were matched on key demographic variables. A repeated measures MANOVA yielded no difference in subtest scores when administered in any of these conditions. The results show no evidence of fatigue or ordering effects on the Letter Number Sequencing subtest.

  10. Letters and Letter Writing.

    ERIC Educational Resources Information Center

    Frese, Millie K., Ed.

    1998-01-01

    "The Goldfinch" is a periodical that introduces young children to various facets of Iowa history. Each issue has a different theme topic and a number of articles covering diverse aspects of the topic being addressed. This issue focuses on letters and letter writing. Featured articles discuss letters that illuminate historical events. The…

  11. Effects of posterior segment disorders on oscillatory displacement thresholds, and on acuities as measured using the potential acuity meter and laser interferometer.

    PubMed

    Barrett, B T; Davison, P A; Eustace, P E

    1994-04-01

    Oscillatory displacement thresholds (ODTs) were measured in 67 subjects with clear ocular media, but known posterior segment disorders. The ability of these thresholds to assess reduced visual function, as quantified by visual acuity deficits, was compared with that of the Potential Acuity Meter (PAM) and the Rodenstock Retinometer (RR). ODTs were found to be sensitive to acuity deficits which were retinal/neural in origin. Despite the fact that interferometric acuities are, unlike ODTs, a measure of resolution, the RR proved no more accurate in assessing the level of letter acuity which existed than did ODT measurement. As would be expected, the PAM provided for the most accurate means of assessing non-optical visual acuity deficits. However, the PAM proved to be less useful in eyes with: very poor levels of acuity, and certain anomalous conditions. The results have implications for the relative ability of each of the three tests to identify reduced visual function behind cataract.

  12. Impact of visual acuity on developing literacy at age 4–5 years: a cohort-nested cross-sectional study

    PubMed Central

    Bruce, Alison; Fairley, Lesley; Chambers, Bette; Wright, John; Sheldon, Trevor A

    2016-01-01

    Objectives To estimate the prevalence of poor vision in children aged 4–5 years and determine the impact of visual acuity on literacy. Design Cross-sectional study linking clinical, epidemiological and education data. Setting Schools located in the city of Bradford, UK. Participants Prevalence was determined for 11 186 children participating in the Bradford school vision screening programme. Data linkage was undertaken for 5836 Born in Bradford (BiB) birth cohort study children participating both in the Bradford vision screening programme and the BiB Starting Schools Programme. 2025 children had complete data and were included in the multivariable analyses. Main outcome measures Visual acuity was measured using a logMAR Crowded Test (higher scores=poorer visual acuity). Literacy measured by Woodcock Reading Mastery Tests-Revised (WRMT-R) subtest: letter identification (standardised). Results The mean (SD) presenting visual acuity was 0.14 (0.09) logMAR (range 0.0–1.0). 9% of children had a presenting visual acuity worse than 0.2logMAR (failed vision screening), 4% worse than 0.3logMAR (poor visual acuity) and 2% worse than 0.4logMAR (visually impaired). Unadjusted analysis showed that the literacy score was associated with presenting visual acuity, reducing by 2.4 points for every 1 line (0.10logMAR) reduction in vision (95% CI −3.0 to −1.9). The association of presenting visual acuity with the literacy score remained significant after adjustment for demographic and socioeconomic factors reducing by 1.7 points (95% CI −2.2 to −1.1) for every 1 line reduction in vision. Conclusions Prevalence of decreased visual acuity was high compared with other population-based studies. Decreased visual acuity at school entry is associated with reduced literacy. This may have important implications for the children's future educational, health and social outcomes. PMID:26883240

  13. The neurology of visual acuity.

    PubMed

    Frisén, L

    1980-09-01

    A series of patients with well defined lesions of various parts of the visual pathways was studied in an attempt to iluminate the neuropathophysiology of visual acuity. Acuity was found to remain normal in all cases with unilateral retrochiasmal lesions, including those of the optic tract. Bilateral retrochiasmal lesions involving the foveal nerve fibres on both sides impaired acuity to the same degree in both eyes. Lateral chiasmal lesions regularly produced impaired acuity in the ipsilateral eye. Midchiasmal lesions commonly led to an impairment of visual acuity in both eyes, usually asymmetrically, and roughly proportionate to the severity of the visual field defect. Compression optic neuropathy was found to reduce acuity in rough proportion to the severity of compression. It was concluded that acuity remains normal as long as either the crossing or the non-crossing neural outflow from the retinal fovea remains intact: acuity fails only when both sets of nerve fibres are compromised. A properly executed acuity test seems to be a powerful tool for detecting such conditions. The lower limit of normal acuity should never be set below 1.0 or 20/20: even this level is clearly subnormal in many subjects.

  14. The Fuzzy Scarlet Letter

    ERIC Educational Resources Information Center

    Pallas, Aaron M.

    2012-01-01

    Critics of the public release of teacher evaluation scores sometimes liken these ratings to the scarlet letter worn by Hester Prynne in Nathaniel Hawthorne's classic novel. The comparison is apt. But public school teachers who are subjected to public shaming because of their students' test scores can rarely expect the opportunities for redemption…

  15. Contour interaction for foveal acuity targets at different luminances.

    PubMed

    Bedell, Harold E; Siderov, John; Waugh, Sarah J; Zemanová, Romana; Pluháček, František; Musilová, Lenka

    2013-08-30

    Single-letter visual acuity is impaired by nearby flanking stimuli, a phenomenon known as contour interaction. We showed previously that when foveal acuity is degraded by a reduction of letter contrast, both the magnitude and angular spatial extent of foveal contour interaction remain unchanged. In this study, we asked whether contour interaction also remains unchanged when foveal visual acuity is degraded by a reduction of the target's background luminance. Percent correct letter identification was measured for isolated, near-threshold black Sloan letters and for letters surrounded by 4 flanking bars in 10 normal observers, 5 at Anglia Ruskin University, UK (ARU) and 5 at Palacky University, Czech Republic (PU). A stepwise reduction in the background luminance over 3 log units resulted in an approximately threefold increase in the near-threshold letter size. At each background luminance, black flanking bars with a width equal to 1 letter stroke were presented at separations between approximately 0.45 and 4.5 min arc (ARU) or 0.32 and 3.2 min arc (PU). The results indicate that the angular extent of contour interaction remains unchanged at approximately 4 min arc at all background luminances. On the other hand, the magnitude of contour interaction decreases systematically as luminance is reduced, from approximately a 50% reduction to a 30% reduction in percent correct. The constant angular extent and decreasing magnitude of contour interaction with a reduction of background luminance suggest foveal contour interaction is mediated by luminance-dependent lateral inhibition within a fixed angular region.

  16. 38 CFR 4.76 - Visual acuity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Visual acuity. 4.76... DISABILITIES Disability Ratings The Organs of Special Sense § 4.76 Visual acuity. (a) Examination of visual acuity. Examination of visual acuity must include the central uncorrected and corrected visual acuity...

  17. Visual acuity with reversed-contrast charts: II. Clinical investigation.

    PubMed

    Westheimer, Gerald; Chu, Patricia; Huang, Wendy; Tran, Thuy; Dister, Robert

    2003-11-01

    Snellen visual acuity was measured in 106 patients ranging in age from 20 to 88 years in routine examinations in the general refraction clinic with two kinds of charts: the standard chart using black letters on a white background and a reversed-contrast display featuring white letters on a black background. The overall ratio of the white-on-black to the black-on-white Snellen fractions was 1.043. A scattergram relating this ratio to patient age revealed that the older the patient, the more the visual acuity was improved by switching to the reversed-contrast chart, with a regression line slope of 0.5 +/- 0.10. Impairment of the eye's optics, in particular by intraocular scatter causing a widening and flattening of the eye's point-spread function, explains these findings and suggests prognostic and therapeutic value of reversing the contrast polarity of displays.

  18. Key drivers of visual acuity gains in neovascular age-related macular degeneration in real life: findings from the AURA study

    PubMed Central

    Holz, Frank G; Tadayoni, Ramin; Beatty, Stephen; Berger, Alan; Cereda, Matteo Giuseppe; Hykin, Philip; Staurenghi, Giovanni; Wittrup-Jensen, Kim; Altemark, Andreas; Nilsson, Jonas; Kim, Kun; Sivaprasad, Sobha

    2016-01-01

    Background/aims To identify predictive markers for the outcomes of anti-vascular endothelial growth factor therapy for neovascular age-related macular degeneration (nAMD). Methods AURA was a retrospective, observational, multicentre study that monitored the 2-year outcomes following intravitreal ranibizumab treatment in patients with nAMD. Using stepwise regression analysis, we evaluated the association between visual acuity outcomes, baseline characteristics and resource utilisation in order to determine which variables are significantly linked to outcomes in AURA. We also examined the relationship between visual acuity outcomes and number of injections received. Results Analyses were performed using data from year 1 (n=1695) and year 2 completers (n=1184). Logistic analysis showed that baseline visual acuity score, age at start of therapy, number of ophthalmoscopies and optical coherence tomography (OCT) (combined) and number of injections (ranibizumab) were significant (p<0.05) prognostic factors for vision maintenance (loss <15 letters) or vision gain (≥15 letters). Patients who received >7 injections (in 1 year) or >14 injections (over 2 years) gained more letters and demonstrated greater vision maintenance (loss of <15 letters) than patients who received fewer injections. There was a significant (p<0.05) association between number of injections and national reimbursement schemes and OCT. Conclusions A number of factors that are predictive of treatment outcomes in a real-life setting were identified. Notably, the decline of treatment benefits may be linked to number of injections and a failure to visit clinicians and receive OCT as required. These findings may be helpful in guiding ophthalmologist treatment decisions under limited time and financial constraints. Trial registration number NCT01447043. PMID:27030279

  19. Response Classification Images in Vernier Acuity

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Beard, B. L.; Ellis, Stephen R. (Technical Monitor)

    1997-01-01

    Orientation selective and local sign mechanisms have been proposed as the basis for vernier acuity judgments. Linear image features contributing to discrimination can be determined for a two choice task by adding external noise to the images and then averaging the noises separately for the four types of stimulus/response trials. This method is applied to a vernier acuity task with different spatial separations to compare the predictions of the two theories. Three well-practiced observers were presented around 5000 trials of a vernier stimulus consisting of two dark horizontal lines (5 min by 0.3 min) within additive low-contrast white noise. Two spatial separations were tested, abutting and a 10 min horizontal separation. The task was to determine whether the target lines were aligned or vertically offset. The noises were averaged separately for the four stimulus/response trial types (e.g., stimulus = offset, response = aligned). The sum of the two 'not aligned' images was then subtracted from the sum of the 'aligned' images to obtain an overall image. Spatially smoothed images were quantized according to expected variability in the smoothed images to allow estimation of the statistical significance of image features. The response images from the 10 min separation condition are consistent with the local sign theory, having the appearance of two linear operators measuring vertical position with opposite sign. The images from the abutting stimulus have the same appearance with the two operators closer together. The image predicted by an oriented filter model is similar, but has its greatest weight in the abutting region, while the response images fall to nonsignificance there. The response correlation image method, previously demonstrated for letter discrimination, clarifies the features used in vernier acuity.

  20. Visual acuity, color vision, and visual search performance at sea.

    PubMed

    Donderi, D C

    1994-03-01

    Visual acuity and color vision were tested during a search and rescue exercise at sea. Fifty-seven watchkeepers searched for orange and yellow life rafts during daylight and for lighted and unlighted life rafts at night with night vision goggles. There were 588 individual watches of one hour each. Measures of wind, waves, and weather were used as covariates. Daytime percentage detection was positively correlated with low-contrast visual acuity and negatively correlated with error scores on Dvorine pseudoisochromatic plates and the Farnsworth color test. Performance was better during the first half-hour of the watch. Efficiency calculations show that color vision selective screening at one standard deviation above the mean would increase daylight search performance by 10% and that one standard deviation visual acuity selection screening would increase performance by 12%. There was no relationship between either acuity or color vision and life raft detection using night vision goggles.

  1. Which children benefit from letter names in learning letter sounds?

    PubMed

    Treiman, Rebecca; Pennington, Bruce F; Shriberg, Lawrence D; Boada, Richard

    2008-03-01

    Typical U.S. children use their knowledge of letters' names to help learn the letters' sounds. They perform better on letter sound tests with letters that have their sounds at the beginnings of their names, such as v, than with letters that have their sounds at the ends of their names, such as m, and letters that do not have their sounds in their names, such as h. We found this same pattern among children with speech sound disorders, children with language impairments as well as speech sound disorders, and children who later developed serious reading problems. Even children who scored at chance on rhyming and sound matching tasks performed better on the letter sound task with letters such as v than with letters such as m and h. Our results suggest that a wide range of children use the names of letters to help learn the sounds and that phonological awareness, as conventionally measured, is not required in order to do so.

  2. Comparison of the STYCAR and lighthouse acuity tests.

    PubMed

    Kastenbaum, S M; Kepford, K L; Holmstrom, E T

    1977-07-01

    In a study comparing the Screening Test for Young Children and Retardates (STYCAR) and the New York Lighthouse Flash Card Test, 50 preschool children (median age of 4.4 yr) were evaluated twice with each instrument. Results indicate that the Lighthouse test had higher reliability, better visual acuity scores, lower untestability rates, and shorter testing times than the STYCAR.

  3. Age Differences in the Relationship between Visual Movement Imagery and Performance on Kinesthetic Acuity Tests.

    ERIC Educational Resources Information Center

    Livesey, David J.

    2002-01-01

    Investigated the relationship between Vividness of Movement Imagery Questionnaire scores and kinesthetic acuity--the sense of body position and movement--among 10- and 14-year-olds. Found that in the older group, those with high levels of visual movement imagery performed better on measures of kinesthetic acuity; no such effect was found for…

  4. Letter identification and the neural image classifier.

    PubMed

    Watson, Andrew B; Ahumada, Albert J

    2015-02-12

    Letter identification is an important visual task for both practical and theoretical reasons. To extend and test existing models, we have reviewed published data for contrast sensitivity for letter identification as a function of size and have also collected new data. Contrast sensitivity increases rapidly from the acuity limit but slows and asymptotes at a symbol size of about 1 degree. We recast these data in terms of contrast difference energy: the average of the squared distances between the letter images and the average letter image. In terms of sensitivity to contrast difference energy, and thus visual efficiency, there is a peak around ¼ degree, followed by a marked decline at larger sizes. These results are explained by a Neural Image Classifier model that includes optical filtering and retinal neural filtering, sampling, and noise, followed by an optimal classifier. As letters are enlarged, sensitivity declines because of the increasing size and spacing of the midget retinal ganglion cell receptive fields in the periphery.

  5. Bayesian model of Snellen visual acuity.

    PubMed

    Nestares, Oscar; Navarro, Rafael; Antona, Beatriz

    2003-07-01

    A Bayesian model of Snellen visual acuity (VA) has been developed that, as far as we know, is the first one that includes the three main stages of VA: (1) optical degradations, (2) neural image representation and contrast thresholding, and (3) character recognition. The retinal image of a Snellen test chart is obtained from experimental wave-aberration data. Then a subband image decomposition with a set of visual channels tuned to different spatial frequencies and orientations is applied to the retinal image, as in standard computational models of early cortical image representation. A neural threshold is applied to the contrast responses to include the effect of the neural contrast sensitivity. The resulting image representation is the base of a Bayesian pattern-recognition method robust to the presence of optical aberrations. The model is applied to images containing sets of letter optotypes at different scales, and the number of correct answers is obtained at each scale; the final output is the decimal Snellen VA. The model has no free parameters to adjust. The main input data are the eye's optical aberrations, and standard values are used for all other parameters, including the Stiles-Crawford effect, visual channels, and neural contrast threshold, when no subject specific values are available. When aberrations are large, Snellen VA involving pattern recognition differs from grating acuity, which is based on a simpler detection (or orientation-discrimination) task and hence is basically unaffected by phase distortions introduced by the optical transfer function. A preliminary test of the model in one subject produced close agreement between actual measurements and predicted VA values. Two examples are also included: (1) application of the method to the prediction of the VAin refractive-surgery patients and (2) simulation of the VA attainable by correcting ocular aberrations.

  6. The Relationship between OCT-measured Central Retinal Thickness and Visual Acuity in Diabetic Macular Edema

    PubMed Central

    2008-01-01

    Objective To compare optical coherence tomography (OCT)-measured retinal thickness and visual acuity in eyes with diabetic macular edema (DME) both before and after macular laser photocoagulation. Design Cross-sectional and longitudinal study. Participants 210 subjects (251 eyes) with DME enrolled in a randomized clinical trial of laser techniques. Methods Retinal thickness was measured with OCT and visual acuity was measured with the electronic-ETDRS procedure. Main Outcome Measures OCT-measured center point thickness and visual acuity Results The correlation coefficients for visual acuity versus OCT center point thickness were 0.52 at baseline and 0.49, 0.36, and 0.38 at 3.5, 8, and 12 months post-laser photocoagulation. The slope of the best fit line to the baseline data was approximately 4.4 letters (95% C.I.: 3.5, 5.3) better visual acuity for every 100 microns decrease in center point thickness at baseline with no important difference at follow-up visits. Approximately one-third of the variation in visual acuity could be predicted by a linear regression model that incorporated OCT center point thickness, age, hemoglobin A1C, and severity of fluorescein leakage in the center and inner subfields. The correlation between change in visual acuity and change in OCT center point thickening 3.5 months after laser treatment was 0.44 with no important difference at the other follow-up times. A subset of eyes showed paradoxical improvements in visual acuity with increased center point thickening (7–17% at the three time points) or paradoxical worsening of visual acuity with a decrease in center point thickening (18%–26% at the three time points). Conclusions There is modest correlation between OCT-measured center point thickness and visual acuity, and modest correlation of changes in retinal thickening and visual acuity following focal laser treatment for DME. However, a wide range of visual acuity may be observed for a given degree of retinal edema and paradoxical

  7. Visual Acuity and the Eye.

    ERIC Educational Resources Information Center

    Beynon, J.

    1985-01-01

    Shows that visual acuity is a function of the structure of the eye and that its limit is set by the structure of the retina, emphasizing the role of lens aberrations and difraction on image quality. Also compares human vision with that of other vertebrates and insects. (JN)

  8. Placing clinical variables on a common linear scale of empirically based risk as a step towards construction of a general patient acuity score from the electronic health record: a modelling study

    PubMed Central

    Rothman, Steven I; Rothman, Michael J; Solinger, Alan B

    2013-01-01

    Objective To explore the hypothesis that placing clinical variables of differing metrics on a common linear scale of all-cause postdischarge mortality provides risk functions that are directly correlated with in-hospital mortality risk. Design Modelling study. Setting An 805-bed community hospital in the southeastern USA. Participants 42302 inpatients admitted for any reason, excluding obstetrics, paediatric and psychiatric patients. Outcome measures All-cause in-hospital and postdischarge mortalities, and associated correlations. Results Pearson correlation coefficients comparing in-hospital risks with postdischarge risks for creatinine, heart rate and a set of 12 nursing assessments are 0.920, 0.922 and 0.892, respectively. Correlation between postdischarge risk heart rate and the Modified Early Warning System (MEWS) component for heart rate is 0.855. The minimal excess risk values for creatinine and heart rate roughly correspond to the normal reference ranges. We also provide the risks for values outside that range, independent of expert opinion or a regression model. By summing risk functions, a first-approximation patient risk score is created, which correctly ranks 6 discharge categories by average mortality with p<0.001 for differences in category means, and Tukey's Honestly Significant Difference Test confirmed that the means were all different at the 95% confidence level. Conclusions Quantitative or categorical clinical variables can be transformed into risk functions that correlate well with in-hospital risk. This methodology provides an empirical way to assess inpatient risk from data available in the Electronic Health Record. With just the variables in this paper, we achieve a risk score that correlates with discharge disposition. This is the first step towards creation of a universal measure of patient condition that reflects a generally applicable set of health-related risks. More importantly, we believe that our approach opens the door to a way of

  9. Dynamic visual acuity using "far" and "near" targets

    NASA Technical Reports Server (NTRS)

    Peters, Brian T.; Bloomberg, Jacob J.

    2005-01-01

    CONCLUSIONS: DVA may be useful for assessing the functional consequences of an impaired gaze stabilization mechanism or for testing the effectiveness of a rehabilitation paradigm. Because target distance influences the relative contributions of canal and otolith inputs, the ability to measure DVA at near and far viewing distances may also lead to tests that will independently assess canal and otolith function. OBJECTIVE: To present and test a methodology that uses dynamic visual acuity (DVA) to assess the efficacy of compensatory gaze mechanisms during a functionally relevant activity that differentially measures canal and otolith function. MATERIAL AND METHODS: The effect of treadmill walking at a velocity of 1.79 m/s on subjects' visual acuity was assessed at each of two viewing distances. A custom-written threshold determination program was used to display Landolt C optotypes on a laptop computer screen during a "far" (4 m) target condition and on a micro-display for a "near" (50 cm) target condition. The walking acuity scores for each target distance were normalized by subtracting a corresponding acuity measure obtained while standing still on the treadmill belt. RESULTS: As predicted by subjective reports of relative target motion, the decrease in visual acuity was significantly greater (p < 0.00001) for the near compared to the far condition.

  10. A Pilot Study to Propose a "Harm Scale", a New Method to Predict Risk of Harm to the Corneal Endothelium Caused by Longitudinal Phacoemulsification, and the Subsequent Effect of Endothelial Damage on Post Operative Visual Acuity

    PubMed Central

    Sorrentino, Francesco Saverio; Bonifazzi, Claudio; Parmeggiani, Francesco; Perri, Paolo

    2016-01-01

    Purpose To study the effect of longitudinal phacoemulsification energy on corneal endothelium and to evaluate the relationship between changes of endothelial cells and postoperative visual acuity. Methods This prospective clinical observational cohort study included 50 patients with cataract who underwent longitudinal phacoemulsification. Sequential quantitative and qualitative morphometric endothelial cell analyses of the cornea were performed 4 weeks preoperatively and 6 weeks postoperatively using noncontact specular microscopy. Results There was a relationship between ECL percentage (ECL%) and the 5-score harm scale, well-described by a linear model (one-way ANOVA, R2 = 73.3%). Analyzing the distribution of ECL% Mean with Tukey post-hoc pairwise comparison test (P < 0.001), the value of ECL = 20% has been regarded as cut-off to discriminate patients who obtained an excellent postoperative best-corrected visual acuity (BCVA > 85 letters) from those who just had a good visual outcome (BCVA ≤ 85 letters). There was a significant correlation among the 5-score harm scale, phaco energy intraoperatively delivered, and average cell area postoperatively. Conclusions The 5-score harm scale, a new method that enables to pigeonhole cataracts taking into account nucleus hardness and phaco times, allows to predict the harm on corneal endothelium after longitudinal phacoemulsification. Assessment of ECL% permits to discriminate between patients with excellent BCVA and with just good BCVA, postoperatively. PMID:26761198

  11. Phenomenological model of visual acuity

    NASA Astrophysics Data System (ADS)

    Gómez-Pedrero, José A.; Alonso, José

    2016-12-01

    We propose in this work a model for describing visual acuity (V) as a function of defocus and pupil diameter. Although the model is mainly based on geometrical optics, it also incorporates nongeometrical effects phenomenologically. Compared to similar visual acuity models, the proposed one considers the effect of astigmatism and the variability of best corrected V among individuals; it also takes into account the accommodation and the "tolerance to defocus," the latter through a phenomenological parameter. We have fitted the model to the V data provided in the works of Holladay et al. and Peters, showing the ability of this model to accurately describe the variation of V against blur and pupil diameter. We have also performed a comparison between the proposed model and others previously published in the literature. The model is mainly intended for use in the design of ophthalmic compensations, but it can also be useful in other fields such as visual ergonomics, design of visual tests, and optical instrumentation.

  12. Visual Acuity, Contrast Sensitivity and Color Vision Three Years After Iodine-125 Brachytherapy for Choroidal and Ciliary Body Melanoma

    PubMed Central

    Tsui, Irena; Beardsley, Robert M; McCannel, Tara A; Oliver, Scott C; Chun, Melissa W; Lee, Steve P; Chow, Phillip E; Agazaryan, Nzhde; Yu, Fei; Straatsma, Bradley R

    2015-01-01

    Purpose : To report visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after iodine-125 brachytherapy for choroidal and ciliary body melanoma (CCM). Design : Prospective interventional case series. Participants : Thirty-seven patients (37 eyes) with CCM. Methods : Patients had best-corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity, Pelli-Robson contrast sensitivity and Hardy-Rand-Rittler color vision measurement; comprehensive ophthalmology examination; optical coherence tomography; and ultrasonography at baseline prior to, 1 year after, 2 years after and 3 years after I-125 brachytherapy. Main Outcome Measures : Visual acuity, contrast sensitivity and color vision prior to, 1 year after, 2 years after and 3 years after brachytherapy. Results : Nineteen (19) men and 18 women with mean age of 58 years (SD 13, range 30-78) prior to, 1 year after, 2 years after and 3 years after brachytherapy had mean best-corrected visual acuity of 77 letters (20/32), 65 letters (20/50), 56 letters (20/80) and 47 letters (20/125); contrast sensitivity of 30, 26, 22 and 19 letters; color vision of 26, 20, 17 and 14 test figures, respectively. Decrease in visual acuity, contrast sensitivity and color vision was statistically significant from baseline at 1 year, 2 years, and 3 years after brachytherapy. Decreased acuity at 3 years was associated with mid-choroid and macula melanoma location, ≥ 4.1 mm melanoma height, radiation maculopathy and radiation optic neuropathy. Conclusion : 1, 2 and 3 years after brachytherapy, eyes with CCM had significantly decreased visual acuity, contrast sensitivity and color vision. PMID:26312123

  13. Nurse-patient assignment models considering patient acuity metrics and nurses' perceived workload.

    PubMed

    Sir, Mustafa Y; Dundar, Bayram; Barker Steege, Linsey M; Pasupathy, Kalyan S

    2015-06-01

    Patient classification systems (PCSs) are commonly used in nursing units to assess how many nursing care hours are needed to care for patients. These systems then provide staffing and nurse-patient assignment recommendations for a given patient census based on these acuity scores. Our hypothesis is that such systems do not accurately capture workload and we conduct an experiment to test this hypothesis. Specifically, we conducted a survey study to capture nurses' perception of workload in an inpatient unit. Forty five nurses from oncology and surgery units completed the survey and rated the impact of patient acuity indicators on their perceived workload using a six-point Likert scale. These ratings were used to calculate a workload score for an individual nurse given a set of patient acuity indicators. The approach offers optimization models (prescriptive analytics), which use patient acuity indicators from a commercial PCS as well as a survey-based nurse workload score. The models assign patients to nurses in a balanced manner by distributing acuity scores from the PCS and survey-based perceived workload. Numerical results suggest that the proposed nurse-patient assignment models achieve a balanced assignment and lower overall survey-based perceived workload compared to the assignment based solely on acuity scores from the PCS. This results in an improvement of perceived workload that is upwards of five percent.

  14. Comparison of three night vision intensification tube technologies on resolution acuity: results from grating and Hoffman ANV-126 tasks

    NASA Astrophysics Data System (ADS)

    Macuda, Todd; Allison, Robert S.; Thomas, Paul; Truong, Long; Tang, Denis; Craig, Greg; Jennings, Sion

    2005-05-01

    Several methodologies have been used to determine resolution acuity through Night Vision Goggles. The present study compared NVG acuity estimates derived from the Hoffman ANV-126 and a standard psychophysical grating acuity task. For the grating acuity task, observers were required to discriminate between horizontal and vertical gratings according to a method of constant stimuli. Psychometric functions were generated from the performance data, and acuity thresholds were interpolated at a performance level of 70% correct. Acuity estimates were established at three different illumination levels (0.06-5X10-4 lux) for both procedures. These estimates were then converted to an equivalent Snellen value. The data indicate that grating acuity estimates were consistently better (i.e. lower scores) than acuity measures obtained from the Hoffman ANV-126. Furthermore significant differences in estimated acuity were observed using different tube technologies. In keeping with previous acuity investigations, although the Hoffman ANV-126 provides a rapid operational assessment of tube acuity, it is suggested that more rigorous psychophysical procedures such as the grating task described here be used to assess the real behavioural resolution of tube technologies.

  15. Prediction of Visual Acuity from Wavefront Aberrations

    NASA Technical Reports Server (NTRS)

    Watson, Andrew B. (Inventor); Ahumada, Albert J. (Inventor)

    2013-01-01

    A method for generating a visual acuity metric, based on wavefront aberrations (WFAs), associated with a test subject and representing classes of imperfections, such as defocus, astigmatism, coma and spherical aberrations, of the subject's visual system. The metric allows choices of different image template, can predict acuity for different target probabilities, can incorporate different and possibly subject-specific neural transfer functions, can predict acuity for different subject templates, and incorporates a model of the optotype identification task.

  16. Writing More Informative Letters of Reference

    PubMed Central

    Wright, Scott M; Ziegelstein, Roy C

    2004-01-01

    Writing a meaningful and valuable letter of reference is not an easy task. Several factors influence the quality of any letter of reference. First, the accuracy and reliability of the writer's impressions and judgment depend on how well he knows the individual being described. Second, the writer's frame of reference, which is determined by the number of persons at the same level that he has worked with, will impact the context and significance of his beliefs and estimations. Third, the letter-writing skills of the person composing the letter will naturally affect the letter. To support the other components of a candidate's application, a letter of reference should provide specific examples of how an individual's behavior or attitude compares to a reference group and should assess “intangibles” that are hard to glean from a curriculum vitae or from test scores. This report offers suggestions that should help physicians write more informative letters of reference. PMID:15109330

  17. Olympic Scoring of English Compositions

    ERIC Educational Resources Information Center

    Follman, John; Panther, Edward

    1974-01-01

    Examines empirically the efficacy of utilizing Olympic diving and gymnastic scoring systems for grading graduate students' English compositions. Results indicated that such scoring rules do not produce ratings different in reliability or in level from conventional letter grades. (ED)

  18. Vernier acuity through night vision goggles.

    PubMed

    Rabin, J

    1993-08-01

    Night vision goggles (NVG's) are being used increasingly in military and civilian environments. Despite the use of these devices, relatively few tests exist to assess visual performance through NVG's. Hyperacuity tasks may provide a sensitive index of performance through night vision devices. In this study, grating vernier acuity was measured through NVG's. As reported previously, a power law relation was observed between vernier acuity and stimulus contrast. Comparison of vernier acuity with and without NVG's indicated that performance is limited by the contrast transfer of the device. Vernier acuity measurements can be used to assess the quality of vision and quantity of contrast transferred through night vision devices.

  19. 38 CFR 4.76 - Visual acuity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... distance and near vision using Snellen's test type or its equivalent. (b) Evaluation of visual acuity. (1) Evaluate central visual acuity on the basis of corrected distance vision with central fixation, even if a central scotoma is present. However, when the lens required to correct distance vision in the poorer...

  20. 38 CFR 4.76 - Visual acuity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... distance and near vision using Snellen's test type or its equivalent. (b) Evaluation of visual acuity. (1) Evaluate central visual acuity on the basis of corrected distance vision with central fixation, even if a central scotoma is present. However, when the lens required to correct distance vision in the poorer...

  1. 38 CFR 4.76 - Visual acuity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... distance and near vision using Snellen's test type or its equivalent. (b) Evaluation of visual acuity. (1) Evaluate central visual acuity on the basis of corrected distance vision with central fixation, even if a central scotoma is present. However, when the lens required to correct distance vision in the poorer...

  2. 38 CFR 4.76 - Visual acuity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... distance and near vision using Snellen's test type or its equivalent. (b) Evaluation of visual acuity. (1) Evaluate central visual acuity on the basis of corrected distance vision with central fixation, even if a central scotoma is present. However, when the lens required to correct distance vision in the poorer...

  3. The relationship between visual acuity and functioning and well-being among diabetics.

    PubMed

    Lee, P P; Whitcup, S M; Hays, R D; Spritzer, K; Javitt, J

    1995-08-01

    Given the enormous recent interest in functional capabilities related to vision, the goal of this study was to examine the relationship of standard clinical measures of vision (e.g. Snellen acuity) to functioning and well-being. The association between Snellen visual acuity, Amsler grid distortion and presence of diabetic retinopathy with self-reported functioning and well-being (SF-36) were examined in a sample of 327 diabetics from the Medical Outcomes Study (MOS). There was little or no correlation between Snellen visual acuity, Amsler grid distortion or diabetic retinopathy and functioning and well-being (i.e. SF-36 scales). Maximum product-moment correlation was 0.15 with worst eye visual acuity, 0.13 with best eye visual acuity, 0.08 with presence of retinopathy, and 0.10 with Amsler grid distortion. Analysis of variance revealed that visual acuity (both best and worst eye) was statistically related only to the physical function scale; no other exam measure was related to any other SF-36 scale score. Snellen visual acuity, Amsler distortion and diabetic retinopathy correlate weakly with patient self-reported functioning and well-being. Thus, the information provided by functioning and well-being measures is complementary to that of standard clinical measures of visual ability.

  4. Closed surfaces of constant visual acuity in symmetric dioptric power space.

    PubMed

    Rubin, A; Harris, W F

    2001-10-01

    This paper demonstrates a multivariate approach to understanding the complicated relations of visual acuity to refractive state or ametropia. Other approaches, as previously used, included graphical representations of lines or profiles of iso-oxyopia (Peters, 1961). But one limitation of Peters' method is that cylinder axis was ignored. However, here the relationship between visual acuity and refractive power will be represented by estimated closed surfaces of constant visual acuity in symmetric dioptric power space. At or near the common center (of several closed surfaces, for example) is the refractive compensation. Coming outwards from such a center, the visual acuity drops in all directions in the space. The primary purpose of this paper was to present estimated closed surfaces of constant visual acuity for several eyes. Various procedures were performed on several subjects including measurement of iris aperture diameter, subjective refraction, and autorefraction. Thereafter, an automated phoropter and either Jackson cross-cylinders or spheres were used to influence dioptric blur or defocus in the subjects. The visual stimulus was a computer-generated nondirectional or meridionally independent letter O. Ovoidal surfaces fit the measurements obtained (with Jackson cross-cylinders and spheres) better than ellipsoidal surfaces. The cross-section, in symmetric dioptric power space, at powers with the same nearest equivalent sphere as the refractive compensation is elliptical in many cases and reflects a dependence of visual acuity on cylinder axis. The surfaces differ when powers are changed so that one is moving away from (decompensation surfaces) or toward (accompensation surfaces) the refractive compensation. The multivariate and graphical methods used in this paper probably have implications for the direction of future research in a number of areas involving measures of vision function such as autorefraction, retinoscopy, subjective refraction, and visual

  5. Stereopsis and positional acuity under dark adaptation.

    PubMed

    Livingstone, M S; Hubel, D H

    1994-03-01

    Though experience tells us we can perceive depth in dim light, it is not so obvious that one of the chief mechanisms for depth perception, stereopsis, is possible under scotopic conditions. The only studies on human stereopsis in the dark adapted state seem to be those of Nagel [(1902) Zeitschrift für Psychologie, 27, 264-266] and Mueller and Lloyd [(1948) Proceedings of the National Academy of Science, U.S.A., 34, 223-227], both of which used real objects or line stereograms. We tested stereopsis using both random-dot and line stereograms and, in agreement with these studies, found that stereopsis is indeed possible in dark adaptation. We also measured stereo acuity and positional acuity (both of which are examples of hyperacuity) and compared these with grating acuity at several levels of light and dark adaptation. At all illumination levels tested, acuities for stereopsis and relative line position were both higher than for grating acuity. As light levels decreased, positional and grating acuity declined in parallel fashion, whereas stereoacuity declined more steeply.

  6. Believing is seeing: using mindlessness (mindfully) to improve visual acuity.

    PubMed

    Langer, Ellen; Djikic, Maja; Pirson, Michael; Madenci, Arin; Donohue, Rebecca

    2010-05-01

    These experiments show that vision can be improved by manipulating mind-sets. In Study 1, participants were primed with the mind-set that pilots have excellent vision. Vision improved for participants who experientially became pilots (by flying a realistic flight simulator) compared with control participants (who performed the same task in an ostensibly broken flight simulator). Participants in an eye-exercise condition (primed with the mind-set that improvement occurs with practice) and a motivation condition (primed with the mind-set "try and you will succeed") demonstrated visual improvement relative to the control group. In Study 2, participants were primed with the mind-set that athletes have better vision than nonathletes. Controlling for arousal, doing jumping jacks resulted in greater visual acuity than skipping (perceived to be a less athletic activity than jumping jacks). Study 3 took advantage of the mind-set primed by the traditional eye chart: Because letters get progressively smaller on successive lines, people expect that they will be able to read the first few lines only. When participants viewed a reversed chart and a shifted chart, they were able to see letters they could not see before. Thus, mind-set manipulation can counteract physiological limits imposed on vision.

  7. A Retrospective Analysis Comparing the New Standardized Letter of Recommendation in Dermatology with the Classic Narrative Letter of Recommendation.

    PubMed

    Kaffenberger, Jessica A; Mosser, Joy; Lee, Grace; Pootrakul, Llana; Harfmann, Katya; Fabbro, Stephanie; Faith, Esteban Fernandez; Carr, David; Plotner, Alisha; Zirwas, Matthew; Kaffenberger, Benjamin H

    2016-09-01

    Background: In an effort to avoid numerous problems associated with narrative letters of recommendation, a dermatology standardized letter of recommendation was utilized in the 2014-2015 resident application cycle. Objective: A comparison of the standardized letter of recommendation and narrative letters of recommendation from a single institution and application cycle to determine if the standardized letter of recommendation met its original goals of efficiency, applicant stratification, and validity. Methods: Eight dermatologists assessed all standardized letters of recommendation/narrative letters of recommendation pairs received during the 2014-2015 application cycle. Five readers repeated the analysis two months later. Each letter of recommendation was evaluated based on a seven question survey. Letter analysis and survey completion for each letter was timed. Results: Compared to the narrative letters of recommendation, the standardized letter of recommendation is easier to interpret (p<0.0001), has less exaggeration of applicants' positive traits (p<0.001), and has higher inter-rater and intrarater reliability for determining applicant traits including personality, reliability, work-ethic, and global score. Standardized letters of recommendation are also faster to interpret (p<0.0001) and provide more information about the writer's background or writer-applicant relationship than narrative letters of recommendation (p<0.001). Limitations: This study was completed at a single institution. Conclusions: The standardized letter of recommendation appears to be meeting its initial goals of 1) efficiency, 2) applicant stratification, and 3) validity. (J Clin Aesthet Dermatol. 2016;9(9):36-2.).

  8. Evidence of Alphabetic Knowledge in Writing: Connections to Letter and Word Identification Skills in Preschool and Kindergarten

    ERIC Educational Resources Information Center

    Molfese, Victoria J.; Beswick, Jennifer L.; Jacobi-Vessels, Jill L.; Armstrong, Natalie E.; Culver, Brittany L.; White, Jamie M.; Ferguson, Melissa C.; Rudasill, Kathleen Moritz; Molfese, Dennis L.

    2011-01-01

    The writing skills of 286 children (157 female and 129 male) were studied by comparing name writing and letter writing scores from preschool to kindergarten with letter and word reading scores over the same time period. Two rubrics for scoring writing were compared to determine if scores based on multiple components (i.e., letter formation,…

  9. Visual Acuity Assessment in Persons with Dementia. Research Report

    ERIC Educational Resources Information Center

    Morse, Alan R.; Teresi, Jeanne; Rosenthal, Bruce; Holmes, Douglas; Yatzkan, Elaine S.

    2004-01-01

    Most studies of vision in persons with Alzheimer's disease either exclude those with advanced dementia or are unable to assess their vision adequately, and therefore, improperly report these persons' visual acuity status. In this study, visual acuity was assessed using the ETDRS Snellen-type acuity chart and Teller Acuity Cards. The Teller Acuity…

  10. Nonamblyopic eye visual acuity through Bangerter filters

    PubMed Central

    Rutstein, Robert P.; Foster, Nicole C.; Cotter, Susan A.; Kraker, Raymond T.; Lee, Dave H.; Melia, Michele; Quinn, Graham E.; Tamkins, Susanna M.; Wallace, David K.

    2011-01-01

    Purpose To describe the amount of visual acuity degradation induced by Bangerter filters in the better-seeing eye and to evaluate its stability over time in children with moderate amblyopia. Methods Visual acuity with and without a Bangerter filter was measured in the nonamblyopic eye of 186 children with moderate amblyopia who were then treated with either patching or with the Bangerter filters. A 0.2 filter was used for amblyopia of 20/80 and a 0.3 filter for amblyopia from 20/40 to 20/63. For the 89 children randomized to Bangerter filters, visual acuity was also measured in the nonamblyopic eye with and without the filters at both 6 weeks and 12 weeks after initiating treatment. Results Mean degradation in visual acuity of the nonamblyopic eye at baseline was 5.1 logMAR lines with the 0.2 filter and 4.8 logMAR lines with the 0.3 filter. The degradation with each filter did not always agree with the manufacturer’s specifications. Over time, the amount of degradation with the filters decreased. Conclusions The 0.2 and 0.3 Bangerter filters degrade nonamblyopic eye visual acuity sufficiently in amblyopic children. Because the amount of degradation decreases over time, it is recommended to periodically apply a new filter when using this type of amblyopia treatment. PMID:21419678

  11. Potential acuity meter for predicting visual acuity after Nd:YAG posterior capsulotomy

    SciTech Connect

    Smiddy, W.E.; Radulovic, D.; Yeo, J.H.; Stark, W.J.; Maumenee, A.E.

    1986-03-01

    We studied 30 patients with opacifications of the posterior capsule to determine if the potential acuity meter (PAM) could accurately predict final visual outcome after Nd:YAG discussion. The final visual acuity was within one line of the PAM prediction in 22 of 30 patients (73%), better by two or more lines in seven patients (23%), and worse in one patient (4%) by two lines. Although in thicker capsules the final acuity was occasionally better than the PAM prediction, the rates of false negative and false positive predictions were very low. Mild cystoid macular edema (3 patients), age-related macular degeneration (3 patients), intraocular lens status, and level of initial acuity did not diminish PAM accuracy. The PAM effectively predicts final visual acuity after YAG posterior capsulotomy, when used in a patient, unhurried manner.

  12. The Effect of Movement-Based Training upon the Aural Acuity of Conductors.

    ERIC Educational Resources Information Center

    Hayslett, Dennis

    1996-01-01

    Examines the effect of physical movement on the aural acuity of conducting subjects using the the Seashore Measures of Musical Talents. Reveals that subjects who received movement training showed significantly higher gain scores than those who had not. Proposes the integration of movement-based training into the conducting curriculum. (DSK)

  13. Developmental letter position dyslexia.

    PubMed

    Friedmann, Naama; Rahamim, Einav

    2007-09-01

    Letter position dyslexia (LPD) is a peripheral dyslexia that causes errors of letter order within words. So far, only cases of acquired LPD have been reported. This study presents selective LPD in its developmental form, via the testing of II Hebrew-speaking individuals with developmental dyslexia. The study explores the types of errors and effects on reading in this dyslexia, using a variety of tests: reading aloud, lexical decision, same-different decision, definition and letter naming. The findings indicate that individuals with developmental LPD have a deficit in the letter position encoding function of the orthographic visual analyser, which leads to underspecification of letter position within words. Letter position errors occur mainly in adjacent middle letters, when the error creates another existing word. The participants did not show an output deficit or phonemic awareness deficit. The selectivity of the deficit, causing letter position errors but no letter identity errors and no migrations between words, supports the existence of letter position encoding function as separate from letter identification and letter-to-word binding.

  14. RED-LETTER DAYS

    EPA Science Inventory

    The word "red-letter" is an adjective meaning "of special significance." It's origin is from the practice of marking Christian holy days in red letters on calendars. The "red-letter days" to which I refer occurred while I was a graduate student of ...

  15. Van: An Open Letter

    ERIC Educational Resources Information Center

    Tieman, John Samuel

    2011-01-01

    This essay is an open letter from a classroom teacher to a concerned citizen. The letter lists a variety of problems caused largely by standardization and the more corrosive effects of positivism. Many of these problems are unknown to those outside the immediate school setting. While the letter focuses on a specific setting, an inner city school…

  16. Dissociating spatial and letter-based word length effects observed in readers' eye movement patterns.

    PubMed

    Hautala, Jarkko; Hyönä, Jukka; Aro, Mikko

    2011-08-01

    In previous eye movement research on word length effects, spatial width has been confounded with the number of letters. McDonald (2006) unconfounded these factors by rendering all words in sentences in constant spatial width. In the present study, the Arial font with proportional letter spacing was used for varying the number of letters while equating for spatial width, while the Courier font with monospaced letter spacing was used to measure the contribution of spatial width to the observed word length effect. Number of letters in words affected single fixation duration on target words, whereas words' spatial width determined fixation locations in words and the probability of skipping a word. The results support the existence of distinct subsystems for deciding where and when to move eyes in text (Rayner & McConkie, 1976). The number-of-letters effect in fixation duration may be explained by visual acuity, visual crowding, and/or serial letter processing.

  17. Learning to write letters: examination of student and letter factors.

    PubMed

    Puranik, Cynthia S; Petscher, Yaacov; Lonigan, Christopher J

    2014-12-01

    Learning to write the letters of the alphabet is an important part of learning how to write conventionally. In this study, we investigated critical factors in the development of letter-writing skills using exploratory item response models to simultaneously account for variance in responses due to differences between students and between letters. Letter-writing skills were assessed in 415 preschool children aged 3 to 5 years. At the student level, we examined the contribution of letter-name knowledge, letter-sound knowledge, and phonological awareness to letter-writing skills. At the letter level, we examined seven intrinsic and extrinsic factors in understanding how preschool children learn to write alphabet letters: first letter of name, letters in name, letter order, textual frequency, number of strokes, symmetry, and letter type. Results indicated that variation in letter-writing skills was accounted for more by differences between students rather than by differences between letters, with most of the variability accounted for by letter-name knowledge and age. Although significant, the contribution of letter-sound knowledge and phonological awareness was relatively small. Student-level mechanisms underlying the acquisition of letter-writing skills are similar to the mechanisms underlying the learning of letter sounds. However, letter characteristics, which appear to play a major role in the learning of letter names and letter sounds, did not appear to influence learning how to write letters in a substantial way. The exception was if the letter was in the child's name.

  18. Lapse resistance in the verbal letter reporting task.

    PubMed

    Arditi, Aries

    2006-04-01

    Lapses, or misreporting errors, can affect accuracy of threshold measurements. Assumptions about lapse rate, especially in untrained observers, have consequently guided the design of at least one clinical psychophysical test. Lapse rate was assessed using a verbal letter identification paradigm like that used in visual acuity and letter contrast sensitivity testing. Subjects occasionally made slip-of-the tongue errors but spontaneously corrected them. Lapse rate (excluding such errors) was 0-3 errors per 1,536 (average rate of 0.0005). In this common clinical paradigm, in which observers set their reporting pace, and where opportunity to amend responses is available, lapse rate is negligible.

  19. Visual Acuity of Children: United States.

    ERIC Educational Resources Information Center

    Health Services and Mental Health Administration (DHEW), Bethesda, MD.

    National estimates based on the findings from the Health Examination Survey in 1963 to 1965 of uncorrected monocular and binocular visual-acuity levels of children were studied. A nationwide sample of 7,417 children was selected to represent the approximately 24 million noninstitutionalized American children between ages 6 and 11 years. Testing…

  20. The relationship between perifoveal achromatic, L- and M-cone acuity and retinal structure as assessed with multimodal high resolution imaging.

    PubMed

    Baraas, Rigmor C; Gjelle, Jon V B; Finstad, Elisabeth Bratlie; Jacobsen, Siri Bjørnetun; Gilson, Stuart J

    2016-07-02

    The relationships between perifoveal measures of achromatic-, L- and M-cone acuity and retinal structure were investigated in healthy young males. Thirty-two males, aged 20-39years, with normal foveal logMAR letter acuity and no observed ocular abnormalities participated in the study. Achromatic and isolated L- and M-cone spatial acuity was measured in the dominant eye with a Sloan E letter of 90% achromatic decrement contrast or 23% increment cone contrast, respectively. Separately, the central part of the same eye was imaged with high-resolution spectral-domain optical coherence tomography (SD-OCT) and adaptive optics ophthalmoscopy (AOO). Thickness measures and cone density in the fovea and parafoveal region were not correlated with perifoveal structural measures. A significant correlation was observed between thicker retinal pigment epithelium (RPE) complex, higher cone density and better L-cone logMAR at 5deg eccentricity, but not for achromatic or M-cone logMAR. The results imply that single letter perifoveal L-cone acuity, rather than achromatic acuity, may provide a useful measure for assessing the structure-function relationship and detecting early changes in the perifoveal cone mosaic.

  1. Out of sight, out of mind? Relations between visual acuity and cognition.

    PubMed

    La Fleur, Claire G; Salthouse, Timothy A

    2014-10-01

    Prior research has established significant relations between measures of sensory ability and cognitive function in adults of different ages, and several explanations for this relation have been proposed. One explanation is that sensory abilities restrict cognitive processing, a second is that cognitive abilities influence assessments of sensory ability, and a third is that both sensory function and cognition are affected by a common, potentially age-based, third factor. These explanations were investigated using mediation and moderation analyses, with near visual acuity as the sensory measure and scores on visual speed tests and auditory memory tests as the cognitive measures. Measures of visual acuity, speed, and memory were obtained from three moderately large samples, two cross-sectional (N = 380, N = 4,779) and one longitudinal (N = 2,258), with participants ranging from 18 to 90 years of age. The visual acuity and cognitive measures had different age trajectories, and the visual acuity-cognition relations were similar in each 5-year age band. The results suggest that the age-related differences and changes in near visual acuity are unlikely to contribute to the age-related differences and changes in speed and memory measures.

  2. [The best corrected presenting distance visual acuity in forensic medicine].

    PubMed

    Liu, Rui-Jue

    2011-06-01

    At present the sight impairment evaluation in forensic medicine of China is based on the international classification of disease by WHO in 1973. The main measured indicator is "best corrected visual acuity". It is different from "presenting distance visual acuity" in some situations. In the new blindness and vision loss classification made by WHO in 2003, "presenting distance visual acuity" took the place of the "best corrected visual acuity". In the practice of forensic medicine, "presenting distance visual acuity" can not reflect the real visual acuity duo to the exaggeration or disguise of the wounded. We suggest to use "the best corrected presenting distance visual acuity" instead of "presenting distance visual acuity" in order to avoid the influences of the exaggeration or disguise of the wounded.

  3. Associations among Visual Acuity and Vision- and Health-Related Quality of Life among Patients in the Multicenter Uveitis Steroid Treatment Trial

    PubMed Central

    Drye, Lea T.; Kempen, John H.; Dunn, James P.; Holland, Gary N.; Latkany, Paul; Rao, Narsing A.; Sen, H. Nida; Sugar, Elizabeth A.; Thorne, Jennifer E.; Wang, Robert C.; Holbrook, Janet T.

    2012-01-01

    Purpose. To evaluate the associations between visual acuity and self-reported visual function; visual acuity and health-related quality of life (QoL) metrics; a summary measure of self-reported visual function and health-related QoL; and individual domains of self-reported visual function and health-related QoL in patients with uveitis. Methods. Best-corrected visual acuity, vision-related functioning as assessed by the NEI VFQ-25, and health-related QoL as assessed by the SF-36 and EuroQoL EQ-5D questionnaires were obtained at enrollment in a clinical trial of uveitis treatments. Multivariate regression and Spearman correlations were used to evaluate associations between visual acuity, vision-related function, and health-related QoL. Results. Among the 255 patients, median visual acuity in the better-seeing eyes was 20/25, the vision-related function score indicated impairment (median, 60), and health-related QoL scores were within the normal population range. Better visual acuity was predictive of higher visual function scores (P ≤ 0.001), a higher SF-36 physical component score, and a higher EQ-5D health utility score (P < 0.001). The vision-specific function score was predictive of all general health-related QoL (P < 0.001). The correlations between visual function score and general quality of life measures were moderate (ρ = 0.29–0.52). Conclusions. The vision-related function score correlated positively with visual acuity and moderately positively with general QoL measures. Cost–utility analyses relying on changes in generic healthy utility measures will be more likely to detect changes when there are clinically meaningful changes in vision-related function, rather than when there are only changes in visual acuity. (ClinicalTrials.gov number, NCT00132691.) PMID:22247489

  4. Evaluation of Visual Acuity Measurements after Autorefraction versus Manual Refraction in Eyes with and without Diabetic Macular Edema

    PubMed Central

    Sun, Jennifer K.; Qin, Haijing; Aiello, Lloyd Paul; Melia, Michele; Beck, Roy W.; Andreoli, Christopher M.; Edwards, Paul A.; Glassman, Adam R.; Pavlica, Michael R.

    2012-01-01

    Objective To compare visual acuity (VA) scores after autorefraction versus research protocol manual refraction in eyes of patients with diabetes and a wide range of VA. Methods Electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) VA Test© letter score (EVA) was measured after autorefraction (AR-EVA) and after Diabetic Retinopathy Clinical Research Network (DRCR.net) protocol manual refraction (MR-EVA). Testing order was randomized, study participants and VA examiners were masked to refraction source, and a second EVA utilizing an identical manual refraction (MR-EVAsupl) was performed to determine test-retest variability. Results In 878 eyes of 456 study participants, median MR-EVA was 74 (Snellen equivalent approximately 20/32). Spherical equivalent was often similar for manual and autorefraction (median difference: 0.00, 5th and 95th percentiles −1.75 to +1.13 Diopters). However, on average, MR-EVA results were slightly better than AR-EVA results across the entire VA range. Furthermore, variability between AR-EVA and MR-EVA was substantially greater than the test-retest variability of MR-EVA (P<0.001). Variability of differences was highly dependent on autorefractor model. Conclusions Across a wide range of VA at multiple sites using a variety of autorefractors, VA measurements tend to be worse with autorefraction than manual refraction. Differences between individual autorefractor models were identified. However, even among autorefractor models comparing most favorably to manual refraction, VA variability between autorefraction and manual refraction is higher than the test-retest variability of manual refraction. The results suggest that with current instruments, autorefraction is not an acceptable substitute for manual refraction for most clinical trials with primary outcomes dependent on best-corrected VA. PMID:22159173

  5. Variable acuity remote viewing system flight demonstration

    NASA Technical Reports Server (NTRS)

    Fisher, R. W.

    1983-01-01

    The Variable Acuity Remote Viewing System (VARVS), originally developed under contract to the Navy (ONR) as a laboratory brassboard, was modified for flight demonstration. The VARVS system was originally conceived as a technique which could circumvent the acuity/field of view/bandwidth tradeoffs that exists in remote viewing to provide a nearly eye limited display in both field of view (160 deg) and resolution (2 min arc) while utilizing conventional TV sensing, transmission, and display equipment. The modifications for flight demonstration consisted of modifying the sensor so it could be installed and flow in a Piper PA20 aircraft, equipped for remote control and modifying the display equipment so it could be integrated with the NASA Research RPB (RPRV) remote control cockpit.

  6. The neural correlates of learned motor acuity

    PubMed Central

    Yang, Juemin; Caffo, Brian; Mazzoni, Pietro; Krakauer, John W.

    2014-01-01

    We recently defined a component of motor skill learning as “motor acuity,” quantified as a shift in the speed-accuracy trade-off function for a task. These shifts are primarily driven by reductions in movement variability. To determine the neural correlates of improvement in motor acuity, we devised a motor task compatible with magnetic resonance brain imaging that required subjects to make finely controlled wrist movements under visual guidance. Subjects were imaged on day 1 and day 5 while they performed this task and were trained outside the scanner on intervening days 2, 3, and 4. The potential confound of performance changes between days 1 and 5 was avoided by constraining movement time to a fixed duration. After training, subjects showed a marked increase in success rate and a reduction in trial-by-trial variability for the trained task but not for an untrained control task, without changes in mean trajectory. The decrease in variability for the trained task was associated with increased activation in contralateral primary motor and premotor cortical areas and in ipsilateral cerebellum. A global nonlocalizing multivariate analysis confirmed that learning was associated with increased overall brain activation. We suggest that motor acuity is acquired through increases in the number of neurons recruited in contralateral motor cortical areas and in ipsilateral cerebellum, which could reflect increased signal-to-noise ratio in motor output and improved state estimation for feedback corrections, respectively. PMID:24848466

  7. Visual Acuity after Cataract Surgery in Patients with Age-Related Macular Degeneration. Age-Related Eye Disease Study 2 Report No. 5

    PubMed Central

    Huynh, Nancy; Nicholson, Benjamin P.; Agrón, Elvira; Clemons, Traci E.; Bressler, Susan B.; Rosenfeld, Philip J.; Chew, Emily Y.

    2014-01-01

    Objective To evaluate visual acuity outcomes after cataract surgery in persons with varying severity of age-related macular degeneration (AMD). Design Cohort study. Participants A total of 1232 eyes of 793 participants who underwent cataract surgery during the Age-Related Eye Disease Study 2 (AREDS2), a prospective, multicenter, randomized controlled trial of nutritional supplements for treatment of AMD. Methods Preoperative and postoperative characteristics of participants who underwent cataract extraction during the 5 year trial were analyzed. Both clinical data and standardized red-reflex lens and fundus photographs were obtained at baseline and annually. Photographs were graded by a centralized reading center for cortical and posterior subcapsular lens opacities and for AMD severity. Cataract surgery was documented at annual study visits or by history during the 6 month telephone calls. Analyses were conducted using multivariate repeated-measures regression. Main Outcome Measures Change in best-corrected visual acuity (BCVA) after cataract surgery compared with preoperative BCVA. Results Adjusting for age at time of surgery, gender, interval between preoperative and postoperative visits, and type and severity of cataract, the mean changes in visual acuity were as follows: eyes with mild AMD (n=30) gained 11.2 letters (95% confidence interval (CI), 6.9-15.5), eyes with moderate AMD (n=346) gained 11.1 letters (95% CI, 9.1-13.2), eyes with severe AMD (n=462) gained 8.7 letters (95% CI, 6.7-10.7), eyes with non-central geographic atrophy (n=70) gained 8.9 letters (95% CI, 5.8-12.1), and eyes with advanced AMD (central geographic atrophy and/or neovascular) AMD (n=324) gained 6.8 letters (95% CI, 4.9-8.8). The visual acuity gain across all AMD severity groups was statistically significant from pre-operative state (P<0.0001). Conclusions Mean visual acuities improved significantly after cataract surgery across varying degrees of AMD severity. PMID:24613825

  8. From Shape to Letters.

    ERIC Educational Resources Information Center

    Schiller, Hillel A.

    In order to make letter shape recognition an integral part of perception training, the use of the line in its two basic shapes is proposed. Letter shapes may seem exceedingly complex linear shapes to young minds. Thus instead of instruction in configuration, instruction involving transformational activities to manipulate and create the…

  9. Location invariance in masked repetition priming of letters and words.

    PubMed

    Marzouki, Yousri; Meeter, Martijn; Grainger, Jonathan

    2013-01-01

    Earlier studies have suggested that information from a prime stimulus can be integrated with target information even when the two stimuli appear at different spatial locations. Here, we examined such location invariance in a masked repetition priming paradigm with single letter and word stimuli. In order to neutralize effects of acuity and spatial attention on prime processing, subliminal prime stimuli always appeared on fixation. Target location varied randomly from trial to trial along the horizontal meridian at one of seven possible locations for letter stimuli (-7° to +7°) and three positions for word stimuli (-4°, 0°, +4°). Speed of responding to letter and word targets was affected by target location, and by priming, but the size of repetition priming effects did not vary as a function of target location. These results suggest that masked repetition priming is mediated by representations that integrate information about object identity independently of object location.

  10. Which Children Benefit from Letter Names in Learning Letter Sounds?

    ERIC Educational Resources Information Center

    Treiman, Rebecca; Pennington, Bruce F.; Shriberg, Lawrence D.; Boada, Richard

    2008-01-01

    Typical U.S. children use their knowledge of letters' names to help learn the letters' sounds. They perform better on letter sound tests with letters that have their sounds at the beginnings of their names, such as v, than with letters that have their sounds at the ends of their names, such as m, and letters that do not have their sounds in their…

  11. Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices

    PubMed Central

    Livingstone, I. A. T.; Tarbert, C. M.; Giardini, M. E.; Bastawrous, A.; Middleton, D.; Hamilton, R.

    2016-01-01

    Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m2) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%). Two charts were operating beyond manufacturer’s recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out

  12. Photometric Compliance of Tablet Screens and Retro-Illuminated Acuity Charts As Visual Acuity Measurement Devices.

    PubMed

    Livingstone, I A T; Tarbert, C M; Giardini, M E; Bastawrous, A; Middleton, D; Hamilton, R

    2016-01-01

    Mobile technology is increasingly used to measure visual acuity. Standards for chart-based acuity tests specify photometric requirements for luminance, optotype contrast and luminance uniformity. Manufacturers provide some photometric data but little is known about tablet performance for visual acuity testing. This study photometrically characterised seven tablet computers (iPad, Apple inc.) and three ETDRS (Early Treatment Diabetic Retinopathy Study) visual acuity charts with room lights on and off, and compared findings with visual acuity measurement standards. Tablet screen luminance and contrast were measured using nine points across a black and white checkerboard test screen at five arbitrary brightness levels. ETDRS optotypes and adjacent white background luminance and contrast were measured. All seven tablets (room lights off) exceeded the most stringent requirement for mean luminance (≥ 120 cd/m2) providing the nominal brightness setting was above 50%. All exceeded contrast requirement (Weber ≥ 90%) regardless of brightness setting, and five were marginally below the required luminance uniformity threshold (Lmin/Lmax ≥ 80%). Re-assessing three tablets with room lights on made little difference to mean luminance or contrast, and improved luminance uniformity to exceed the threshold. The three EDTRS charts (room lights off) had adequate mean luminance (≥ 120 cd/m2) and Weber contrast (≥ 90%), but all three charts failed to meet the luminance uniformity standard (Lmin/Lmax ≥ 80%). Two charts were operating beyond manufacturer's recommended lamp replacement schedule. With room lights on, chart mean luminance and Weber contrast increased, but two charts still had inadequate luminance uniformity. Tablet computers showed less inter-device variability, higher contrast, and better luminance uniformity than charts in both lights-on and lights-off environments, providing brightness setting was >50%. Overall, iPad tablets matched or marginally out

  13. Simulation of thalamic prosthetic vision: reading accuracy, speed, and acuity in sighted humans

    PubMed Central

    Vurro, Milena; Crowell, Anne Marie; Pezaris, John S.

    2014-01-01

    The psychophysics of reading with artificial sight has received increasing attention as visual prostheses are becoming a real possibility to restore useful function to the blind through the coarse, pseudo-pixelized vision they generate. Studies to date have focused on simulating retinal and cortical prostheses; here we extend that work to report on thalamic designs. This study examined the reading performance of normally sighted human subjects using a simulation of three thalamic visual prostheses that varied in phosphene count, to help understand the level of functional ability afforded by thalamic designs in a task of daily living. Reading accuracy, reading speed, and reading acuity of 20 subjects were measured as a function of letter size, using a task based on the MNREAD chart. Results showed that fluid reading was feasible with appropriate combinations of letter size and phosphene count, and performance degraded smoothly as font size was decreased, with an approximate doubling of phosphene count resulting in an increase of 0.2 logMAR in acuity. Results here were consistent with previous results from our laboratory. Results were also consistent with those from the literature, despite using naive subjects who were not trained on the simulator, in contrast to other reports. PMID:25408641

  14. Simulation of thalamic prosthetic vision: reading accuracy, speed, and acuity in sighted humans.

    PubMed

    Vurro, Milena; Crowell, Anne Marie; Pezaris, John S

    2014-01-01

    The psychophysics of reading with artificial sight has received increasing attention as visual prostheses are becoming a real possibility to restore useful function to the blind through the coarse, pseudo-pixelized vision they generate. Studies to date have focused on simulating retinal and cortical prostheses; here we extend that work to report on thalamic designs. This study examined the reading performance of normally sighted human subjects using a simulation of three thalamic visual prostheses that varied in phosphene count, to help understand the level of functional ability afforded by thalamic designs in a task of daily living. Reading accuracy, reading speed, and reading acuity of 20 subjects were measured as a function of letter size, using a task based on the MNREAD chart. Results showed that fluid reading was feasible with appropriate combinations of letter size and phosphene count, and performance degraded smoothly as font size was decreased, with an approximate doubling of phosphene count resulting in an increase of 0.2 logMAR in acuity. Results here were consistent with previous results from our laboratory. Results were also consistent with those from the literature, despite using naive subjects who were not trained on the simulator, in contrast to other reports.

  15. Change in visual acuity is well correlated with change in image-quality metrics for both normal and keratoconic wavefront errors.

    PubMed

    Ravikumar, Ayeswarya; Marsack, Jason D; Bedell, Harold E; Shi, Yue; Applegate, Raymond A

    2013-11-26

    We determined the degree to which change in visual acuity (VA) correlates with change in optical quality using image-quality (IQ) metrics for both normal and keratoconic wavefront errors (WFEs). VA was recorded for five normal subjects reading simulated, logMAR acuity charts generated from the scaled WFEs of 15 normal and seven keratoconic eyes. We examined the correlations over a large range of acuity loss (up to 11 lines) and a smaller, more clinically relevant range (up to four lines). Nine IQ metrics were well correlated for both ranges. Over the smaller range of primary interest, eight were also accurate and precise in estimating the variations in logMAR acuity in both normal and keratoconic WFEs. The accuracy for these eight best metrics in estimating the mean change in logMAR acuity ranged between ±0.0065 to ±0.017 logMAR (all less than one letter), and the precision ranged between ±0.10 to ±0.14 logMAR (all less than seven letters).

  16. Sensory factors limiting horizontal and vertical visual span for letter recognition

    PubMed Central

    Yu, Deyue; Legge, Gordon E.; Wagoner, Gunther; Chung, Susana T. L.

    2014-01-01

    Reading speed for English text is slower for text oriented vertically than horizontally. Yu, Park, Gerold, and Legge (2010) showed that slower reading of vertical text is associated with a smaller visual span (the number of letters recognized with high accuracy without moving the eyes). Three possible sensory determinants of the size of the visual span are: resolution (decreasing acuity at letter positions farther from the midline), mislocations (uncertainty about the relative position of letters in strings), and crowding (interference from flanking letters in recognizing the target letter). In the present study, we asked which of these factors is most important in determining the size of the visual span, and likely in turn in determining the horizontal/vertical difference in reading when letter size is above the critical print size for reading. We used a decomposition analysis to represent constraints due to resolution, mislocations, and crowding as losses in information transmitted (in bits) about letter recognition. Across vertical and horizontal conditions, crowding accounted for 75% of the loss in information, mislocations accounted for 19% of the loss, and declining acuity away from fixation accounted for only 6%. We conclude that crowding is the major factor limiting the size of the visual span, and that the horizontal/vertical difference in the size of the visual span is associated with stronger crowding along the vertical midline. PMID:25187253

  17. Sensory factors limiting horizontal and vertical visual span for letter recognition

    PubMed Central

    Yu, Deyue; Legge, Gordon E.; Wagoner, Gunther; Chung, Susana T. L.

    2014-01-01

    Reading speed for English text is slower for text oriented vertically than horizontally. Yu, Park, Gerold, and Legge (2010) showed that slower reading of vertical text is associated with a smaller visual span (the number of letters recognized with high accuracy without moving the eyes). Three possible sensory determinants of the size of the visual span are: resolution (decreasing acuity at letter positions farther from the midline), mislocations (uncertainty about the relative position of letters in strings), and crowding (interference from flanking letters in recognizing the target letter). In the present study, we asked which of these factors is most important in determining the size of the visual span, and likely in turn in determining the horizontal/vertical difference in reading when letter size is above the critical print size for reading. We used a decomposition analysis to represent constraints due to resolution, mislocations, and crowding as losses in information transmitted (in bits) about letter recognition. Across vertical and horizontal conditions, crowding accounted for 75% of the loss in information, mislocations accounted for 19% of the loss, and declining acuity away from fixation accounted for only 6%. We conclude that crowding is the major factor limiting the size of the visual span, and that the horizontal/vertical difference in the size of the visual span is associated with stronger crowding along the vertical midline.

  18. Visual acuity estimation from simulated images

    NASA Astrophysics Data System (ADS)

    Duncan, William J.

    Simulated images can provide insight into the performance of optical systems, especially those with complicated features. Many modern solutions for presbyopia and cataracts feature sophisticated power geometries or diffractive elements. Some intraocular lenses (IOLs) arrive at multifocality through the use of a diffractive surface and multifocal contact lenses have a radially varying power profile. These type of elements induce simultaneous vision as well as affecting vision much differently than a monofocal ophthalmic appliance. With myriad multifocal ophthalmics available on the market it is difficult to compare or assess performance in ways that effect wearers of such appliances. Here we present software and algorithmic metrics that can be used to qualitatively and quantitatively compare ophthalmic element performance, with specific examples of bifocal intraocular lenses (IOLs) and multifocal contact lenses. We anticipate this study, methods, and results to serve as a starting point for more complex models of vision and visual acuity in a setting where modeling is advantageous. Generating simulated images of real- scene scenarios is useful for patients in assessing vision quality with a certain appliance. Visual acuity estimation can serve as an important tool for manufacturing and design of ophthalmic appliances.

  19. Stream segregation with high spatial acuity

    PubMed Central

    Middlebrooks, John C.; Onsan, Zekiye A.

    2012-01-01

    Spatial hearing is widely regarded as helpful in recognizing a sound amid other competing sounds. It is a matter of debate, however, whether spatial cues contribute to “stream segregation,” which refers to the specific task of assigning multiple interleaved sequences of sounds to their respective sources. The present study employed “rhythmic masking release” as a measure of the spatial acuity of stream segregation. Listeners discriminated between rhythms of noise-burst sequences presented from free-field targets in the presence of interleaved maskers that varied in location. For broadband sounds in the horizontal plane, target-masker separations of ≥8° permitted rhythm discrimination with d′ ≥ 1; in some cases, such thresholds approached listeners’ minimum audible angles. Thresholds were the same for low-frequency sounds but were substantially wider for high-frequency sounds, suggesting that interaural delays provided higher spatial acuity in this task than did interaural level differences. In the vertical midline, performance varied dramatically as a function of noise-burst duration with median thresholds ranging from >30° for 10-ms bursts to 7.1° for 40-ms bursts. A marked dissociation between minimum audible angles and masking release thresholds across the various pass-band and burst-duration conditions suggests that location discrimination and spatial stream segregation are mediated by distinct auditory mechanisms. PMID:23231120

  20. Launch of Zoological Letters.

    PubMed

    Fukatsu, Takema; Kuratani, Shigeru

    2016-02-01

    A new open-access journal, Zoological Letters, was launched as a sister journal to Zoological Science, in January 2015. The new journal aims at publishing topical papers of high quality from a wide range of basic zoological research fields. This review highlights the notable reviews and research articles that have been published in the first year of Zoological Letters, providing an overview on the current achievements and future directions of the journal.

  1. Developmental trajectory of number acuity reveals a severe impairment in developmental dyscalculia.

    PubMed

    Piazza, Manuela; Facoetti, Andrea; Trussardi, Anna Noemi; Berteletti, Ilaria; Conte, Stefano; Lucangeli, Daniela; Dehaene, Stanislas; Zorzi, Marco

    2010-07-01

    Developmental dyscalculia is a learning disability that affects the acquisition of knowledge about numbers and arithmetic. It is widely assumed that numeracy is rooted on the "number sense", a core ability to grasp numerical quantities that humans share with other animals and deploy spontaneously at birth. To probe the links between number sense and dyscalculia, we used a psychophysical test to measure the Weber fraction for the numerosity of sets of dots, hereafter called number acuity. We show that number acuity improves with age in typically developing children. In dyscalculics, numerical acuity is severely impaired, with 10-year-old dyscalculics scoring at the level of 5-year-old normally developing children. Moreover, the severity of the number acuity impairment predicts the defective performance on tasks involving the manipulation of symbolic numbers. These results establish for the first time a clear association between dyscalculia and impaired "number sense", and they may open up new horizons for the early diagnosis and rehabilitation of mathematical learning deficits.

  2. Neural substrates of sensorimotor processes: letter writing and letter perception

    PubMed Central

    James, Karin H.

    2015-01-01

    Writing and perceiving letters are thought to share similar neural substrates; however, what constitutes a neural representation for letters is currently debated. One hypothesis is that letter representation develops from sensorimotor experience resulting in an integrated set of modality-specific regions, whereas an alternative account suggests that letter representations may be abstract, independent of modality. Studies reviewed suggest that letter representation consists of a network of modality-responsive brain regions that may include an abstract component. PMID:26203115

  3. Visual acuity in the cathemeral strepsirrhine Eulemur macaco flavifrons.

    PubMed

    Veilleux, Carrie C; Kirk, E Christopher

    2009-04-01

    Studies of visual acuity in primates have shown that diurnal haplorhines have higher acuity (30-75 cycles per degree (c/deg)) than most other mammals. However, relatively little is known about visual acuity in non-haplorhine primates, and published estimates are only available for four strepsirrhine genera (Microcebus, Otolemur, Galago, and Lemur). We present here the first measurements of visual acuity in a cathemeral strepsirrhine species, the blue-eyed black lemur (Eulemur macaco flavifrons). Acuity in two subjects, a 3-year-old male and a 16-year-old female, was assessed behaviorally using a two-alternative forced choice discrimination task. Visual stimuli consisted of high contrast square wave gratings of seven spatial frequencies. Acuity threshold was determined using a 70% correct response criterion. Results indicate a maximum visual acuity of 5.1 c/deg for the female (1718 trials) and 3.8 c/deg for the male (846 trials). These values for E. macaco are slightly lower than those reported for diurnal Lemur catta, and are generally comparable to those reported for nocturnal Microcebus murinus and Otolemur crassicaudatus. To examine ecological sources of variation in primate visual acuity, we also calculated maximum theoretical acuity for Cheirogaleus medius (2.8 c/deg) and Tarsius syrichta (8.9 c/deg) using published data on retinal ganglion cell density and eye morphology. These data suggest that visual acuity in primates may be influenced by activity pattern, diet, and phylogenetic history. In particular, the relatively high acuity of T. syrichta and Galago senegalensis suggests that visual predation may be an important selective factor favoring high visual acuity in primates.

  4. Letter Recognition and Sound Identification.

    ERIC Educational Resources Information Center

    Prior, Jennifer

    This lesson, which is most appropriate for kindergartners, reviews letter names and their sounds through a group letter recognition activity, a picture book activity, and alphabet practice with several online activities. During three 30-minute sessions, students will: identify the letters of the alphabet; identify the sounds of letters; identify…

  5. Temporal processing deficits in letter-by-letter reading.

    PubMed

    Ingles, Janet L; Eskes, Gail A

    2007-01-01

    Theories of the cognitive impairment underlying letter-by-letter reading vary widely, including prelexical and lexical level deficits. One prominent prelexical account proposes that the disorder results from difficulty in processing multiple letters simultaneously. We investigated whether this deficit extends to letters presented in rapid temporal succession. A letter-by-letter reader, G.M., was administered a rapid serial visual presentation task that has been used widely to study the temporal processing characteristics of the normal visual system. Comparisons were made to a control group of 6 brain-damaged individuals without reading deficits. Two target letters were embedded at varying temporal positions in a stream of rapidly presented single digits. After each stream, the identities of the two letters were reported. G.M. required an extended period of time after he had processed one letter before he was able to reliably identify a second letter, relative to the controls. In addition, G.M.'s report of the second letter was most impaired when it immediately followed the first letter, a pattern not seen in the controls, indicating that G.M. had difficulty processing the two items together. These data suggest that a letter-by-letter reading strategy may be adopted to help compensate for a deficit in the temporal processing of letters.

  6. Association of Visual Acuity and Cognitive Impairment in Older Individuals: Fujiwara-kyo Eye Study.

    PubMed

    Mine, Masashi; Miyata, Kimie; Morikawa, Masayuki; Nishi, Tomo; Okamoto, Nozomi; Kawasaki, Ryo; Yamashita, Hidetoshi; Kurumatani, Norio; Ogata, Nahoko

    2016-01-01

    Both visual impairment and cognitive impairment are essential factors that determine the quality of life in the aged population. The aim of this study was to determine if a correlation existed between visual acuity and cognitive impairment in an elderly Japanese population. The Fujiwara-kyo Eye Study was a cross-sectional study of individuals aged ≥68 years who lived in Nara Prefecture of Japan. Participants underwent ophthalmological examinations and cognitive function test. A mild visual impairment was defined as having a best corrected visual acuity (BCVA) >0.2 logarithm of the minimum angle of resolution (logMAR) units in the better eye. Cognitive impairment was defined as having a Mini-Mental State Examination (MMSE) score of ≤23 points. A total to 2818 individuals completed the examinations. The mean age of the participants was 76.3 ± 4.8 years (mean ± standard deviation). The mean BCVA of the better eye was -0.02 ± 0.13 logMAR units and 6.6% subjects were classified as being mildly visually impaired. The mean MMSE score was 27.3 ± 2.3 and 5.7% subjects were classified as being cognitively impaired. The proportion of subjects with cognitive or moderate visual impairment increased with age, and there was a significant correlation between the visual acuity and MMSE score (r = -0.10, p < 0.0001). Subjects with mild visual impairments had 2.4 times higher odds of having cognitive impairment than those without visual impairment (odds ratio 2.4, 95% confidence interval, 1.5-3.8, p < 0.001) after adjusting for age, sex, and length of education. We conclude that it may be important to maintain good visual acuity to reduce the risk of having cognitive impairment.

  7. Cooperative neural processes involved in stereoscopic acuity.

    PubMed

    Westheimer, G

    1979-08-01

    Results of psychophysical experiments are reported showing that synchrony, appropriate relative placement, and absence of standing disparity are important conditions to be met by members of a target configuration if they are to participate in the cooperative neural processes leading to the best disparity discrimination. Consecutive binocular presentation of the members of a stereo target decreases stereoacuity by a factor of about 10, and a step disparity displacement of a single line target needs to be larger still to be detected as a depth stimulus. A standing disaprity of even one minute of arc at least doubles the disaprity disxrimination threshold. It is postulated that a differencing mechanism operates on the depth signal of individual features; the temporal and spatial optima of target presentation for stereoscopic acuity outline the character of the concerned operations.

  8. How well do you see what you hear? The acuity of visual-to-auditory sensory substitution

    PubMed Central

    Haigh, Alastair; Brown, David J.; Meijer, Peter; Proulx, Michael J.

    2013-01-01

    Sensory substitution devices (SSDs) aim to compensate for the loss of a sensory modality, typically vision, by converting information from the lost modality into stimuli in a remaining modality. “The vOICe” is a visual-to-auditory SSD which encodes images taken by a camera worn by the user into “soundscapes” such that experienced users can extract information about their surroundings. Here we investigated how much detail was resolvable during the early induction stages by testing the acuity of blindfolded sighted, naïve vOICe users. Initial performance was well above chance. Participants who took the test twice as a form of minimal training showed a marked improvement on the second test. Acuity was slightly but not significantly impaired when participants wore a camera and judged letter orientations “live”. A positive correlation was found between participants' musical training and their acuity. The relationship between auditory expertise via musical training and the lack of a relationship with visual imagery, suggests that early use of a SSD draws primarily on the mechanisms of the sensory modality being used rather than the one being substituted. If vision is lost, audition represents the sensory channel of highest bandwidth of those remaining. The level of acuity found here, and the fact it was achieved with very little experience in sensory substitution by naïve users is promising. PMID:23785345

  9. Learning to recognize letters in the periphery: Effects of repeated exposure, letter frequency, and letter complexity

    PubMed Central

    Husk, Jesse S.; Yu, Deyue

    2017-01-01

    Patients with central vision loss must rely on their peripheral vision for reading. Unfortunately, limitations of peripheral vision, such as crowding, pose significant challenges to letter recognition. As a result, there is a need for developing effective training methods for improving crowded letter recognition in the periphery. Several studies have shown that extensive practice with letter stimuli is beneficial to peripheral letter recognition. Here, we explore stimulus-related factors that might influence the effectiveness of peripheral letter recognition training. Specifically, we examined letter exposure (number of letter occurrences), frequency of letter use in English print, and letter complexity and evaluated their contributions to the amount of improvement observed in crowded letter recognition following training. We analyzed data collected across a range of training protocols. Using linear regression, we identified the best-fitting model and observed that all three stimulus-related factors contributed to improvement in peripheral letter recognition with letter exposure being the most important factor. As an important explanatory variable, pretest accuracy was included in the model as well to avoid estimate biases and was shown to have influence on the relationship between training improvement and letter exposure. When developing training protocols for peripheral letter recognition, it may be beneficial to not only consider the overall length of training, but also to tailor the number of stimulus occurrences for each letter according to its initial performance level, frequency, and complexity. PMID:28265651

  10. Astronaut Frank Borman performing visual acuity tests in space

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut Frank Borman is seen performing visual acuity tests in space. Views include Borman looking at the camera as light shines through the capsule window (63712); Borman is using the visual acuity device and a portable mouth thermometer during his experiment (63713).

  11. Brief Report: Visual Acuity in Children with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Albrecht, Matthew A.; Stuart, Geoffrey W.; Falkmer, Marita; Ordqvist, Anna; Leung, Denise; Foster, Jonathan K.; Falkmer, Torbjorn

    2014-01-01

    Recently, there has been heightened interest in suggestions of enhanced visual acuity in autism spectrum disorders (ASD) which was sparked by evidence that was later accepted to be methodologically flawed. However, a recent study that claimed children with ASD have enhanced visual acuity (Brosnan et al. in "J Autism Dev Disord"…

  12. 49 CFR 242.117 - Vision and hearing acuity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Vision and hearing acuity. 242.117 Section 242.117... Requirements § 242.117 Vision and hearing acuity. (a) Each railroad shall adopt and comply with a program which... person's vision and hearing shall meet or exceed the standards prescribed in this section and Appendix...

  13. 49 CFR 242.117 - Vision and hearing acuity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Vision and hearing acuity. 242.117 Section 242.117... Requirements § 242.117 Vision and hearing acuity. (a) Each railroad shall adopt and comply with a program which... person's vision and hearing shall meet or exceed the standards prescribed in this section and Appendix...

  14. 49 CFR 242.117 - Vision and hearing acuity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Vision and hearing acuity. 242.117 Section 242.117... Requirements § 242.117 Vision and hearing acuity. (a) Each railroad shall adopt and comply with a program which... person's vision and hearing shall meet or exceed the standards prescribed in this section and Appendix...

  15. On using Vernier acuity to assess magnocellular sensitivity.

    PubMed

    Skottun, Bernt C; Skoyles, John R

    2010-03-01

    A recent study [Keri, S., & Benedek, G. (2009). Visual pathway deficit in female fragile x premutation carriers: A potential endophenotype. Brain and Cognition, 69, 291-295] has found Vernier acuity deficiencies together with contrast sensitivity defects consistent with a magnocellular deficit in female fragile x premutation carriers. This may appear to support the notion that Vernier acuity may serve as a test of magnocellular sensitivity. However, Vernier acuity deficiencies have been reported in other conditions (e.g., schizophrenia, amblyopia and cortical visual impairment) where there is little evidence for magnocellular deficits. The observation that Vernier acuity deficiencies can occur without magnocellular deficits indicates that Vernier acuity is not a reliable test of magnocellular sensitivity.

  16. Improvement of tactile roughness discrimination acuity correlates with perception of improved hand function in patients after hand surgery.

    PubMed

    Fujimoto, Shuhei; Kon, Noriko

    2016-04-01

    [Purpose] The purpose of this study was to elucidate how well patients' perceptions related to the improvements in their hand function during hospitalization. [Subjects] Sixteen patients who were hospitalized after hand surgery. [Methods] Using the Japanese Society for Surgery of the Hand edition of the Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire; tactile roughness discrimination acuity, motor imagery, motor function, sensory function, and pain of the upper limb were assessed at admission and discharge. Spearman's rank-order correlation coefficients were calculated using the differences in all assessment items at admission and discharge. A multiple regression analysis (stepwise method) was performed to investigate factors that correlated with improvements in Quick-Disabilities of the Arm, Shoulder, and Hand scores. [Results] The improvement of tactile roughness discrimination acuity was significantly associated with patient perception of improved hand function. [Conclusion] The results suggest that an improvement in tactile roughness discrimination acuity was most strongly correlated with patient perception of improved hand function.

  17. Determinants of visual acuity outcomes in eyes with neovascular AMD treated with anti-VEGF agents: an instrumental variable analysis of the AURA study.

    PubMed

    Holz, F G; Tadayoni, R; Beatty, S; Berger, A R; Cereda, M G; Hykin, P; Staurenghi, G; Wittrup-Jensen, K; Nilsson, J; Kim, K; Sivaprasad, S

    2016-08-01

    PurposeTo identify the strongest variable(s) linked with the number of ranibizumab injections and outcomes in AURA, and to identify ways to improve outcomes using this association.MethodsAURA was a large observational study that monitored visual acuity over a 2-year period in patients with neovascular age-related macular degeneration (AMD) who received ranibizumab injections. Baseline characteristics, resource use, and outcomes were analyzed using an instrumental variable approach and regression analysis.ResultsData were analyzed from 2227 patients enrolled in AURA. Optical coherence tomography (OCT) and ophthalmoscopy were the most common diagnostic tests used, and this combination was the strongest instrumental variable. Use of OCT and ophthalmoscopy affected the number of injections given and resulted in an increase in visual acuity gains from baseline of 17.6 letters in year 1 and 2.5 letters in year 2. Regression models using the instrumental variable (OCT and ophthalmoscopy combined) showed that ≥5.1 (95% CI: 3.3-11.4) ranibizumab injections were needed to maintain visual acuity from baseline to year 1 and ≥8.3 (95% CI: 5.3-18.8) injections were needed to maintain visual acuity from year 1 to year 2. To gain ≥15 letters, ≥7.9 (95% CI: 5.1-17.5) ranibizumab injections would be needed in year 1 and ≥16.1 (95% CI: 10.3-36.4) injections would be needed over 2 years.ConclusionsThese findings highlight the role that regular monitoring plays in guiding neovascular AMD therapy and they showed that the number of ranibizumab injections needed to maintain visual acuity is higher than that administered in AURA.

  18. Letters and American Literacy.

    ERIC Educational Resources Information Center

    Kevis, David E.

    The work itself should help a person who is going to teach reading and writing. Practical suggestions are offered in the final two chapters, while the opening three give intellectual perspectives. A theme binds the work of letting the consciousness of writing as a visual system be increased and of breaking the spell by which letter phonetics can…

  19. Inside the Letter

    ERIC Educational Resources Information Center

    Duke, Roger; Graham, Alan

    2007-01-01

    In this article, the authors describe how a Java applet can help to build learners' intuitions about basic ideas of algebra. "Matchbox Algebra" is a Java applet the authors have designed to enable learners to grasp a key idea in learning algebra: that the letter "x" may be thought of as representing an as-yet-unknown number. They describe the…

  20. Letters in this Issue

    NASA Astrophysics Data System (ADS)

    1998-01-01

    Reforming the General Chemistry Textbook individual letters by Edward T. Samulski; Stephen J. Hawkes; Stephen J. Fisher; J. Stephen Hartman; A. R. H. Cole; Stanley Pine, Ronald Archer, and Herbert Kaesz; Jimmy Reeves; Robert Hill; and Brock Spencer, C. Bradley Moore and Nedah Rose. Re: article by R. J. Gillespie The author replies

  1. Harvard Education Letter, 1999.

    ERIC Educational Resources Information Center

    Graves-Desai, Kelly, Ed.

    1999-01-01

    This document is comprised of the six issues in volume 15 of the Harvard Education Letter, a bimonthly newsletter addressing current issues in elementary and secondary education. Articles in this volume include the following: (1) January-February--"Retention vs. Social Promotion: Schools Search for Alternatives" (Kelly), and "School…

  2. Harvard Education Letter, 2002.

    ERIC Educational Resources Information Center

    Gordon, David T., Editor

    2002-01-01

    This document is comprised of the 6 issues in volume 18 of the Harvard Education Letter, a bimonthly newsletter addressing current issues in elementary and secondary education. Articles in this volume include the following: (1) January/February--"Curriculum Access in the Digital Age" (David T. Gordon) and "Using Charters To Improve…

  3. Letter to Doxiadis

    ERIC Educational Resources Information Center

    Fuller, Buckminster

    1969-01-01

    The second half of a lengthy letter to Dr. Constantine Doxiadis (published in full in Main Currents in Modern Thought, XXV, March-April 1969) summarizes Buckminster Fuller's personal reflections on the impact of industrialization and on the effect of technological change in uniting mankind. (MF)

  4. Harvard Education Letter, 2001.

    ERIC Educational Resources Information Center

    Gordon, David, T., Ed.

    2001-01-01

    This document is comprised of the six issues in volume 17 of the Harvard Education Letter, a bimonthly newsletter addressing current issues in elementary and secondary education. Articles in this volume include the following: (1) January-February--"Charters and Districts: Three Stages in an Often Rocky Relationship" (Kelly) and "'We…

  5. Five Long Letters.

    ERIC Educational Resources Information Center

    Bone, Eric

    1990-01-01

    Describes the life of former Louisiana governor Huey Long through five fictitious letters. Discusses Long's experiences as a state public service commissioner, governor, and senator. Attributes Long's assassination to his killer's personal motives. Concludes that Long's life showed how much personal power could be gained even in a democracy. (SG)

  6. Letter case and text legibility in normal and low vision.

    PubMed

    Arditi, Aries; Cho, Jianna

    2007-09-01

    It is thought by cognitive scientists and typographers alike, that lower-case text is more legible than upper-case. Yet lower-case letters are, on average, smaller in height and width than upper-case characters, which suggests an upper-case advantage. Using a single unaltered font and all upper-, all lower-, and mixed-case text, we assessed size thresholds for words and random strings, and reading speeds for text with normal and visually impaired participants. Lower-case thresholds were roughly 0.1 log unit higher than upper. Reading speeds were higher for upper- than for mixed-case text at sizes twice acuity size; at larger sizes, the upper-case advantage disappeared. Results suggest that upper-case is more legible than the other case styles, especially for visually-impaired readers, because smaller letter sizes can be used than with the other case styles, with no diminution of legibility.

  7. Contrast-sensitivity loss in a group of former microelectronics workers with normal visual acuity.

    PubMed

    Frenette, B; Mergler, D; Bowler, R

    1991-07-01

    The measurement of contrast sensitivity at varying grating frequencies is used increasingly to study visual and neural disorders. It provides more information than conventional acuity measures. Refractive errors initially affect high spatial frequencies, whereas lower spatial frequencies are affected only when these errors are pronounced. Neurophysiological alterations are reflected by depressed sensitivity to coarse gratings. Visual dysfunction has been associated with workplace exposures to a wide range of organic solvents. In microelectronics assembly where large quantities of organic solvents are used in many aspects of the work processes, visual deficits have been observed. The objective of the present study was to compare contrast sensitivity among former microelectronics assembly workers, with normal far and near visual acuity, and a reference group from the same region, with similar acuity. No significant differences were observed between scores at the two ends of the contrast sensitivity curves; however, at the intermediate spatial frequencies, the former microelectronics workers' scores were significantly lower (Student's t-test; p less than 0.05). For the microelectronics workers, no relation was observed between age and contrast sensitivity at any spatial frequency, whereas for the reference group, contrast sensitivity scores were progressively lower with age at spatial frequencies greater than or equal to 6.0 cpd (r2 = 0.15 at 6 cpd to r2 = 0.45 at 18.0 cpd), suggesting that for the former there is some form of interference with the expected contrast sensitivity loss with age. Lower contrast sensitivity scores in intermediate spatial frequencies, observed among the former microelectronics workers, possibly reflect neural alterations, which may have resulted from exposure to neurotoxic substances. These findings suggest the need for further studies on visual functions in microelectronics workers.

  8. EPA Void Letter for Suzuki

    EPA Pesticide Factsheets

    When a certificate is voided, EPA issues a void letter to the manufacturer.November 30, 2016, letter from Byron Bunker to Suzuki Motor America Inc., voiding certificate of conformity for highway motorcycle engine family CSKXC.652VR1.

  9. Apgar Scores

    MedlinePlus

    ... because she is blue and not pink. Most newborn infants have Apgar scores greater than 7. Because their ... between 8 and 10. A small percentage of newborns have Apgar scores of less than ... low scores than infants with normal births. These scores may reflect difficulties ...

  10. Visual acuity in the short-tailed opossum (Monodelphis domestica).

    PubMed

    Dooley, J C; Nguyen, H M; Seelke, A M H; Krubitzer, L

    2012-10-25

    Monodelphis domestica (short-tailed opossum) is an emerging animal model for studies of neural development due to the extremely immature state of the nervous system at birth and its subsequent rapid growth to adulthood. Yet little is known about its normal sensory discrimination abilities. In the present investigation, visual acuity was determined in this species using the optokinetic test (OPT), which relies on involuntary head tracking of a moving stimulus and can be easily elicited using a rotating visual stimulus of varying spatial frequencies. Using this methodology, we determined that the acuity of Monodelphis is 0.58 cycles per degree (cpd), which is similar to the acuity of rats using the same methodology, and higher than in mice. However, acuity in the short-tailed opossum is lower than in other marsupials. This is in part due to the methodology used to determine acuity, but may also be due to differences in diel patterns, lifestyle and phylogeny. We demonstrate that for the short-tailed opossum, the OPT is a rapid and reliable method of determining a baseline acuity and can be used to study enhanced acuities due to cortical plasticity.

  11. Visual acuity in the short-tailed opossum (Monodelphis domestica)

    PubMed Central

    Dooley, James C.; Nguyen, Hoang; Seelke, Adele M. H.; Krubitzer, Leah

    2013-01-01

    Monodelphis domestica (short-tailed opossum) is an emerging animal model for studies of neural development due to the extremely immature state of the nervous system at birth and its subsequent rapid growth to adulthood. Yet little is known about its normal sensory discrimination abilities. In the present investigation, visual acuity was determined in this species using the optokinetic test (OPT), which relies on involuntary head tracking of a moving stimulus and can be easily elicited using a rotating visual stimulus of varying spatial frequencies. Using this methodology, we determined that the acuity of Monodelphis is 0.58 cycles per degree (cpd), which is similar to the acuity of rats using the same methodology, and higher than in mice. However, acuity in the short-tailed opossum is lower than in other marsupials. This is in part due to the methodology used to determine acuity, but may also be due to differences in diel patterns, lifestyle and phylogeny. We demonstrate that for the short-tailed opossum, the OPT is a rapid and reliable method of determining a baseline acuity and can be used to study enhanced acuities due to cortical plasticity. PMID:22871523

  12. RETENTION OF HIGH TACTILE ACUITY THROUGHOUT THE LIFESPAN IN BLINDNESS

    PubMed Central

    Legge, Gordon E.; Madison, Cindee; Vaughn, Brenna N.; Cheong, Allen M.Y.; Miller, Joseph C.

    2009-01-01

    Previous studies of tactile acuity on the fingertip using passive touch have demonstrated an age-related decline in spatial resolution for both sighted and blind subjects. We have re-examined this age dependence with two newly designed tactile-acuity charts requiring active exploration of the test symbols. One chart used dot patterns similar to Braille and the other used embossed Landolt rings. Groups of blind Braille readers and sighted subjects, ranging in age from 12 to 85 years, were tested in two experiments. We replicated previous findings for sighted subjects by showing an age related decrease in tactile acuity by nearly 1% per year. Surprisingly, the blind subjects retained high acuity into old age showing no age-related decline. For the blind subjects, tactile acuity did not correlate with braille reading speed, the amount of daily reading, or the age at which braille was learned. We conclude that when measured with active touch, blind subjects retain high tactile acuity into old age, unlike their aging sighted peers. We propose that blind people's use of active touch in daily activities, not specifically Braille reading, results in preservation of tactile acuity across the lifespan. PMID:19064491

  13. Restoring Visual Acuity in Dynamic Conditions with a Vestibular Implant

    PubMed Central

    Guinand, Nils; Van de Berg, Raymond; Cavuscens, Samuel; Stokroos, Robert; Ranieri, Maurizio; Pelizzone, Marco; Kingma, Herman; Guyot, Jean-Philippe; Pérez Fornos, Angélica

    2016-01-01

    Vestibular implants are devices designed to rehabilitate patients with a bilateral vestibular loss (BVL). These patients lack a properly functioning vestibulo-ocular reflex (VOR), which impairs gaze stabilization abilities and results in an abnormal loss of visual acuity (VA) in dynamic situations (i.e., severely limiting the patient's ability to read signs or recognize faces while walking). We previously demonstrated that the VOR can be artificially restored in a group of BVL patients fitted with a prototype vestibular implant. This study was designed to investigate whether these promising results could be translated to a close-to-reality task, significantly improving VA abilities while walking. Six BVL patients previously implanted with a vestibular implant prototype participated in the experiments. VA was determined using Sloan letters displayed on a computer screen, in four conditions: (1) with the patient standing still without moving (static), (2) while the patient was walking on a treadmill at constant speed with the vestibular implant prototype turned off (systemOFF), (3) while the patient was walking on a treadmill at constant speed with the vestibular implant prototype turned on providing coherent motion information (systemONmotion), and (4) a “placebo” condition where the patient was walking on a treadmill at constant speed with the vestibular implant prototype turned on providing reversed motion information (systemONsham). The analysis (one-way repeated measures analysis of variance) revealed a statistically significant effect of the test condition [F(3, 12) = 30.5, p < 0.001]. Significant decreases in VA were observed with the systemOFF condition when compared to the static condition (Tukey post-hoc p < 0.001). When the vestibular implant was turned on, delivering pertinent motion information (systemONmotion) the VA improved to close to normal values. The improvement disappeared in the placebo condition (systemONsham) and VA-values also dropped

  14. Dynamic Visual Acuity and Landing Sickness in Crewmembers Returning from Long-Duration Spaceflight

    NASA Technical Reports Server (NTRS)

    Rosenberg, M.J.F; Peters, B.T.; Reschke, M. F.

    2016-01-01

    Long-term exposure to microgravity causes sensorimotor adaptations that result in functional deficits upon returning to a gravitational environment. At landing the vestibular system and the central nervous system, responsible for coordinating head and eye movements, are adapted to microgravity and must re-adapt to the gravitational environment. This re-adaptation causes decrements in gaze control and dynamic visual acuity, with astronauts reporting oscillopsia and blurred vision. Dynamic visual acuity (DVA) is assessed using an oscillating chair developed in the Neuroscience Laboratory at JSC. This chair is lightweight and easily portable for quick deployment in the field. The base of the chair is spring-loaded and allows for manual oscillation of the subject. Using a metronome, the chair is vertically oscillated plus or minus 2 cm at 2 Hz by an operator, to simulate walking. While the subject is being oscillated, they are asked to discern the direction of Landolt-C optotypes of varying sizes and record their direction using a gamepad. The visual acuity thresholds are determined using an algorithm that alters the size of the optotype based on the previous response of the subject using a forced-choice best parameter estimation that is able to rapidly converge on the threshold value. Visual acuity thresholds were determined both for static (seated) and dynamic (oscillating) conditions. Dynamic visual acuity is defined as the difference between the dynamic and static conditions. Dynamic visual acuity measures will be taken prior to flight (typically L-180, L-90, and L-60) and up to eight times after landing, including up to 3 times on R plus 0. Follow up measurements will be taken at R plus 1 (approximately 36 hours after landing). Long-duration International Space Station crewmembers will be tested once at the refueling stop in Europe and once again upon return to Johnson Space Center. In addition to DVA, subjective ratings of motion sickness will be recorded

  15. A comparison of visual acuity, predictability, and visual function outcomes after intracorneal ring segments and laser in situ keratomileusis.

    PubMed Central

    Suiter, B G; Twa, M D; Ruckhofer, J; Schanzlin, D J

    2000-01-01

    PURPOSE: To compare correction of low myopia by intrastromal corneal ring segments (ICRS) and by laser in situ keratomileusis (LASIK) with respect to early visual recovery and refractive outcomes. METHODS: Eighty-two eyes implanted with ICRS in a phase III study for US Food and Drug Administration review were matched with 133 eyes treated with LASIK by criteria of age (> 18 years, < 65 years), preoperative myopia (-1.00 to -3.50 diopters [D]), astigmatism (< or = 1.00 D), single treatment, and attempted full correction. Examinations were performed preoperatively and postoperatively at days 1 and 7 and months 1 and 3. Visual acuity and manifest refraction data were collected retrospectively. Visual function scores were assigned, and summarized results were compared. RESULTS: Uncorrected visual acuity was 20/20 or better at day 1 in 24% of eyes (20/82) after ICRS and in 55% of eyes (73/133) after LASIK, and at month 3 in 75% of eyes (58/77) after ICRS and in 67% of eyes (84/126) after LASIK. Spherical equivalent refraction at month 3 was within +/- 1.00 D of intended correction in 99% of eyes (76/77) after ICRS and in 96% of eyes (121/126) after LASIK. Excellent visual function scores were noted at month 3 in 90% of eyes (69/77) after ICRS and in 78% of eyes (98/126) after LASIK. CONCLUSION: Patients treated with LASIK showed better uncorrected visual acuity immediately following surgery; however, beyond 1 month, patients treated with ICRS achieved better uncorrected visual acuity that continued to improve with time. Visual function scores indicate that ICRS eyes see at higher levels of uncorrected visual acuity than LASIK eyes do with the same refractive error. The ICRS and LASIK were comparable in the correction of mild myopia. PMID:11190040

  16. Manual aiming in healthy aging: does proprioceptive acuity make the difference?

    PubMed

    Helsen, Werner F; Van Halewyck, Florian; Levin, Oron; Boisgontier, Matthieu P; Lavrysen, Ann; Elliott, Digby

    2016-04-01

    The present study examines whether non-active older adults are more dependent on visual information when executing aiming movements and whether age-related declines in proprioception play a mediating role herein. Young (N = 40) and older adults (N = 38) were divided into physically active and non-active subgroups based on self-reported sports participation levels. In experiment 1, participants executed wrist-aiming movements with and without visual feedback. In experiment 2, passive proprioceptive acuity was assessed using wrist motion detection and position matching tests. Results showed similar aiming accuracy across age groups both with and without visual feedback, but older adults exhibited longer movement times, prolonged homing-in phase, and made more corrective submovements. Passive proprioceptive acuity was significantly affected by physical activity level and age, with participants in the active group scoring better than their non-active peers. However, these declines did not predict performance changes on the aiming task. Taken together, our observations suggest that decline in proprioceptive acuity did not predict performance changes on the aiming task and older adults were able to compensate for their decreased motion and position sense when allowed sufficient time. In line with these observations, we proposed that older adults are able to compensate for their decline in proprioception by increasing their reliance on predictive models.

  17. Development and Initial Psychometric Evaluation of the Post-Acute Acuity Rating for Children

    PubMed Central

    O'Brien, Jane E.; Dumas, Helene M.

    2015-01-01

    The Post-Acute Acuity Rating for Children (PAARC) is the first known acuity rating intended to reflect medical severity based on age, reason for admission, diagnoses, dependence in activities of daily living, and technology reliance for children admitted to post-acute care rehabilitation hospitals. Content validity was tested using an expert panel scoring the Content Validity Index (CVI). Concurrent validity was examined using clinician's opinion of acuity at admission, the Complexity Index, and All Patient Refined Diagnosis Related Group (APR-DRG) codes. Predictive validity was examined with acute care readmission within 30 days. Interrater reliability was assessed using admission histories from closed cases. Content validity was established and concurrent validity was moderate to high with clinician opinion (rho = .76, p < .001), the Complexity Index (rho = .76, p < .001), and APR-DRGs (rho = .349, p = .001). Predictive validity was moderate (rho = .504, p = .005) and returns to acute care within 30 days. Interrater reliability was excellent (ICC = 0.97; 95% CI = 0.92–0.90, p < .001). Experts agreed that the PAARC's content is relevant, simple, and representative of the population. The PAARC measured well against indicators of medical complexity for pediatric outpatient care and medical record coding and was reliable between raters. This work supports proceeding with additional development and validity testing of the PAARC. PMID:26609433

  18. A comparison of letter and digit processing in letter-by-letter reading.

    PubMed

    Ingles, Janet L; Eskes, Gail A

    2008-01-01

    The extent to which letter-by-letter reading results from a specific orthographic deficit, as compared with a nonspecific disturbance in basic visuoperceptual mechanisms, is unclear. The current study directly compared processing of letters and digits in a letter-by-letter reader, G.M., using a rapid serial visual presentation (RSVP) task and a speeded matching task. Comparisons were made to a group of six brain-damaged individuals without reading deficits. In the RSVP task, G.M. had increased difficulty reporting the target identities when they were letters, as compared with digits. Although this general pattern was also evident in the control group, the magnitude of the letter-digit accuracy difference was greater in G.M. Similarly, in the matching task, G.M. was slower to match letters than digits, relative to the control group, although his response times to both item types were increased. These data suggest that letter-by-letter reading, at least in this case, results from a visuoperceptual encoding deficit that particularly affects letters, but also extends to processing of digits to a lesser extent. Results are consistent with the notion that a left occipitotemporal area is specialized for letter processing with greater bilaterality in the visual processing of digits.

  19. Allographic Agraphia for Single letters

    PubMed Central

    Menichelli, Alina; Machetta, Francesca; Zadini, Antonella; Semenza, Carlo

    2012-01-01

    The case is reported of a patient (PS) who, following acute encephalitis with residual occipito-temporal damage, showed a selective deficit in writing cursive letters in isolation, but no difficulty to write cursive-case words and non-words. Notably, he was able to recognize the same allographs he could not write and to produce both single letters and words in print. In addition to this selective single letter writing difficulty, the patient demonstrated an inability to correctly perform a series of imagery tasks for cursive letters. PS’s performance may indicate that single letter production requires explicit imagery. Explicit imagery may not be required, instead, when letters have to be produced in the context of a word: letter production in this case may rely on implicit retrieval of well learned scripts in a procedural way. PMID:22713390

  20. The development of an obstetric triage acuity tool.

    PubMed

    Paisley, Kathleen S; Wallace, Ruth; DuRant, Patricia G

    2011-01-01

    The purpose of this article is to describe the journey a multicampus hospital system took to improve the obstetric triage process. A review of literature revealed no current comprehensive obstetric acuity tool, and thus our team developed a tool with a patient flow process, revised and updated triage nurse competencies, and then educated the nurses about the new tool and process. Data were collected to assess the functionality of the new process in assigning acuity upon patient arrival, conveying appropriate acuities based on patient complaints, and initiating the medical screening examination, all within prescribed time intervals. Initially data indicated that processes were still not optimal, and re-education was provided for all triage nurses. This improved all data points. The result of this QI project is that our patients are now seen based on their acuity within designated time frames.

  1. Apgar score

    MedlinePlus

    ... the baby's: Breathing effort Heart rate Muscle tone Reflexes Skin color Each category is scored with 0, ... scores 2 for muscle tone. Grimace response or reflex irritability is a term describing response to stimulation, ...

  2. Measuring Observers’ Visual Acuity Through Night Vision Goggles

    DTIC Science & Technology

    1998-01-01

    a two-alternative, forced-choice ( 2AFC ) method to determine visual acuity through NVGs as a function of night-time ambient illumination levels. A...computer executed the 2AFC (gap seen up or down), Step Program adapted from Simpson (1989). Based on the observerÕs last response, the program selected...threshold levels, NVG drift, good guessing in the 2AFC method, fatigue, eye strain, sinus headaches and so on. METHOD Psychometric Function of Acuity

  3. Visual acuity in mammals: effects of eye size and ecology.

    PubMed

    Veilleux, Carrie C; Kirk, E Christopher

    2014-01-01

    Previous comparative research has attributed interspecific variation in eye size among mammals to selection related to visual acuity. Mammalian species have also been hypothesized to differ in visual acuity partly as a result of differences in ecology. While a number of prior studies have explored ecological and phylogenetic effects on eye shape, a broad comparative analysis of the relationships between visual acuity, eye size and ecology in mammals is currently lacking. Here we use phylogenetic comparative methods to explore these relationships in a taxonomically and ecologically diverse sample of 91 mammal species. These data confirm that axial eye length and visual acuity are significantly positively correlated in mammals. This relationship conforms to expectations based on theoretical optics and prior analyses of smaller comparative samples. Our data also demonstrate that higher visual acuity in mammals is associated with: (1) diurnality and (2) predatory habits once the effects of eye size and phylogeny have been statistically controlled. These results suggest that interspecific variation in mammalian visual acuity is the result of a complex interplay between phylogenetic history, visual anatomy and ecology.

  4. Improving Visual Acuity of Myopes through Operant Training: The Evaluation of Psychological and Physiological Mechanisms Facilitating Acuity Enhancement

    DTIC Science & Technology

    1988-12-01

    at far distances. High degrees of myopia are often accompanied by damage to the eye’s fundus and, when extreme, cannot be fully compensated by...refractively measured myopia . He attributed the improvement to experience in correct interpretation of a blurred visual image . Gibson (1953) proposed that...acuity is an alterable process. If acuity can be enhanced, it could benefit some of the nearly one billion individuals who have myopia or

  5. Letter to an ethicist

    PubMed Central

    Silver, Malcolm; Crelinsten, Gordon

    1995-01-01

    Just as issues have arisen in court that cause the public to question whether the rights of criminals are taking precedence over the rights of victims, some physicians wonder if ethicists are placing the rights of some patients ahead of the rights of society and the common good. Pathologist Malcolm Silver raised this issue in a letter to the editor of CMAJ. With his permission, it was forwarded to Dr. Gordon Crelinsten, past chair of the ethics committee at the Royal Victoria Hospital in Montreal. PMID:7697584

  6. Letters to the Editor

    NASA Astrophysics Data System (ADS)

    1998-03-01

    All the Letters to the Editor in this issue are in the same PostScript or PDF file. Contents Comment on `Magnetic and electric field strengths of high voltage power lines and household appliances' José Luis Giordano Dept. de Ciencia y Tecnología de Materiales y Fluidos, CPSI, Universidad de Zaragoza, Spain Twins paradox S R Carson Norton College, Malton, North Yorkshire, UK On alternative ways of finding the ratio of specific heats of gases Tomas Ficker Physics Department, Technical University of Brno, Czech Republic

  7. Letters to the Editor

    NASA Astrophysics Data System (ADS)

    1998-01-01

    All the Letters to the Editor in this issue are in the same PostScript or PDF file. Contents Physics and history Arthur I Miller Department of Science & Technology Studies, University College London, Gower Street, London WC1E 6BT, UK Physics and history: a reply David Miller Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, UK Cathode rays, the electron and Thomson's discovery John Harris 33 Glentham Road, London SW13 9JD, UK Vectors: swallow them whole! David Wheeler Mahanakorn University of Technology, Bangkok, Thailand

  8. The Two Sides of Sensory–Cognitive Interactions: Effects of Age, Hearing Acuity, and Working Memory Span on Sentence Comprehension

    PubMed Central

    DeCaro, Renee; Peelle, Jonathan E.; Grossman, Murray; Wingfield, Arthur

    2016-01-01

    Reduced hearing acuity is among the most prevalent of chronic medical conditions among older adults. An experiment is reported in which comprehension of spoken sentences was tested for older adults with good hearing acuity or with a mild-to-moderate hearing loss, and young adults with age-normal hearing. Comprehension was measured by participants’ ability to determine the agent of an action in sentences that expressed this relation with a syntactically less complex subject-relative construction or a syntactically more complex object-relative construction. Agency determination was further challenged by inserting a prepositional phrase into sentences between the person performing an action and the action being performed. As a control, prepositional phrases of equivalent length were also inserted into sentences in a non-disruptive position. Effects on sentence comprehension of age, hearing acuity, prepositional phrase placement and sound level of stimulus presentations appeared only for comprehension of sentences with the more syntactically complex object-relative structures. Working memory as tested by reading span scores accounted for a significant amount of the variance in comprehension accuracy. Once working memory capacity and hearing acuity were taken into account, chronological age among the older adults contributed no further variance to comprehension accuracy. Results are discussed in terms of the positive and negative effects of sensory–cognitive interactions in comprehension of spoken sentences and lend support to a framework in which domain-general executive resources, notably verbal working memory, play a role in both linguistic and perceptual processing. PMID:26973557

  9. What Can Reduce Letter Migrations in Letter Position Dyslexia?

    ERIC Educational Resources Information Center

    Friedmann, Naama; Rahamim, Einav

    2014-01-01

    Letter position dyslexia (LPD) is a peripheral dyslexia that causes errors of letter position within words, such as reading "cloud" as "could." In this study, we assessed the effect of various display manipulations and reading methods on the reading of 10 Hebrew readers with developmental LPD. These manipulations included…

  10. Higher Cognitive Function in Elderly Individuals with Previous Cataract Surgery: Cross-Sectional Association Independent of Visual Acuity in the HEIJO-KYO Cohort.

    PubMed

    Miyata, Kimie; Obayashi, Kenji; Saeki, Keigo; Tone, Nobuhiro; Tanaka, Kunihiko; Nishi, Tomo; Morikawa, Masayuki; Kurumatani, Norio; Ogata, Nahoko

    2016-06-01

    Cataract surgery improves visual acuity and drastically increases the capacity for light reception to the retina. Although previous studies suggested that both light exposure and visual acuity were associated with cognitive function, the relationships between cataract surgery, visual acuity, and cognitive function have not been evaluated in large populations. In this cross-sectional study, we measured cognitive function using the Mini-Mental State Examination and best-corrected visual acuity in pseudophakic (previous cataract surgery) and phakic (no previous cataract surgery) elderly individuals. Of 945 participants (mean age 71.7 years), 166 (17.6%) had pseudophakia and 317 (33.5%) had impaired cognitive function (score ≤26). The pseudophakic group showed significantly better visual acuity than the phakic group (p = 0.003) and lower age-adjusted odds ratio (ORs) for cognitive impairment (OR 0.66; p = 0.038). Consistently, in multivariate logistic regression models, after adjusting for confounding factors, including visual acuity and socioeconomic status, ORs for cognitive impairment were significantly lower in the pseudophakic group than in the phakic group (OR 0.64; 95% confidence interval 0.43-0.96; p = 0.031). This association remained significant in sensitivity analysis, excluding participants with low cognitive score ≤23 (n = 36). In conclusion, in a general elderly population, prevalence of cognitive impairment was significantly lower in pseudophakic individuals independently of visual acuity. The association was also independent of several major causes of cognitive impairment such as aging, gender, obesity, socioeconomic status, hypertension, diabetes, sleep disturbances, depressive symptoms, and physical inactivity.

  11. Scoring Package

    National Institute of Standards and Technology Data Gateway

    NIST Scoring Package (PC database for purchase)   The NIST Scoring Package (Special Database 1) is a reference implementation of the draft Standard Method for Evaluating the Performance of Systems Intended to Recognize Hand-printed Characters from Image Data Scanned from Forms.

  12. Propensity Scores

    ERIC Educational Resources Information Center

    Luellen, Jason K.; Shadish, William R.; Clark, M. H.

    2005-01-01

    Propensity score analysis is a relatively recent statistical innovation that is useful in the analysis of data from quasi-experiments. The goal of propensity score analysis is to balance two non-equivalent groups on observed covariates to get more accurate estimates of the effects of a treatment on which the two groups differ. This article…

  13. Content Analysis of Children's Letters to Santa: Toy and Non-Toy Requests.

    ERIC Educational Resources Information Center

    Marcon, Rebecca A.; And Others

    This study examined the letters that 438 children aged 2 through 12 wrote to "Santa Claus" in care of a local newspaper in 1992. The letters were scored for: (1) number of toys requested; (2) non-toy requests; (3) specific requests for others; (4) intangible requests (i.e., world peace); (5) total toy price; and (6) number of toys…

  14. Letters in Biographies and Novels.

    ERIC Educational Resources Information Center

    Paterra, Elizabeth

    1997-01-01

    This is an annotated bibliography of biographies, historical fiction, contemporary stories, and discussion questions related to letter writing. A sidebar suggests an activity that involves reading a book about Ludwig van Beethoven, listening to Beethoven's music, and discussing letters in the story. (DGM)

  15. The Effect of Zeaxanthin on the Visual Acuity of Zebrafish.

    PubMed

    Saidi, Eric A; Davey, Pinakin Gunvant; Cameron, D Joshua

    2015-01-01

    Oral supplementation of carotenoids such as zeaxanthin or lutein which naturally occur in human retina have been shown to improve vision and prevent progression of damage to advanced AMD in some studies. The zebrafish eye shares many physiological similarities with the human eye and is increasingly being used as model for vision research. We hypothesized that injection of zeaxanthin into the zebrafish eye would improve the visual acuity of the zebrafish over time. Visual acuity, calculated in cycles per degree, was measured in adult zebrafish to establish a consistent baseline using the optokinetic response. Zeaxanthin dissolved into phosphate buffered saline (PBS) or PBS only was injected into the anterior chamber of the right and left eyes of the Zebrafish. Visual acuities were measured at 1 week and 3, 8 and 12 weeks post-injection to compare to baseline values. Repeated measures ANOVA was used to compare visual acuities between fish injected with PBS and zeaxanthin. A significant improvement in visual acuity, 14% better than before the injection (baseline levels), was observed one week after injection with zeaxanthin (p = 0.04). This improvement peaked at more than 30% for some fish a few weeks after the injection and improvement in vision persisted at 3 weeks after injection (p = 0.006). The enhanced visual function was not significantly better than baseline at 8 weeks (p = 0.19) and returned to baseline levels 12 weeks after the initial injection (p = 0.50). Zeaxanthin can improve visual acuity in zebrafish eyes. Further studies are required to develop a better understanding of the role zeaxanthin and other carotenoids play during normal visual function.

  16. Fresnel prisms and their effects on visual acuity and binocularity.

    PubMed Central

    Véronneau-Troutman, S

    1978-01-01

    1. The visual acuity with the Fresnel membrane prism is significantly less than that with the conventional prism of the same power for all prism powers from 12 delta through 30 delata at distance and from 15 delta through 30 delta at near. 2. The difference in the visual acuity between base up and base down, and between base in and base out, is not significantly different for either the Fresnel membrane prism or for the conventional prism. 3. For both Fresnel membrane prism and the conventional prism, the visual acuity when looking straight ahead. 4. Using Fresnel membrane prisms of the same power from different lots, the visual acuity varied significantly. The 30 delta prism caused the widest range in visual acuity. 5. When normal subjects are fitted with the higher powers of the Fresnel membrane prism, fusion and stereopsis are disrupted to such an extent that the use of this device to restore or to improve binocular vision in cases with large-angle deviations is seriously questioned. 6. Moreover, the disruption of fusion and stereopsis is abrupt and severe and does not parallel the decrease in visual acuity. The severely reduced ability to maintain fusion may be related to the optical aberrations, which, in turn, may be due to the molding process and the polyvinyl chloride molding material. 7. Through the flexibility of the membrane prism is a definite advantage, because of its proclivity to reduce visual acuity and increase aberrations its prescription for adults often must be limited to only one eye. 8. For the same reasons in the young child with binocular vision problems, the membrane prism presently available should be prescribed over both eyes only in powers less than 20 delta. When the membrane prism is to be used as a partial occluder (over one eye only), any power can be used. 9. The new Fresnel "hard" prism reduces visual acuity minimally and rarely disrupts binocularity, thus increasing the potential for prismotherapy to establish binocularity. This

  17. Human Time-Frequency Acuity Beats the Fourier Uncertainty Principle

    NASA Astrophysics Data System (ADS)

    Oppenheim, Jacob N.; Magnasco, Marcelo O.

    2013-01-01

    The time-frequency uncertainty principle states that the product of the temporal and frequency extents of a signal cannot be smaller than 1/(4π). We study human ability to simultaneously judge the frequency and the timing of a sound. Our subjects often exceeded the uncertainty limit, sometimes by more than tenfold, mostly through remarkable timing acuity. Our results establish a lower bound for the nonlinearity and complexity of the algorithms employed by our brains in parsing transient sounds, rule out simple “linear filter” models of early auditory processing, and highlight timing acuity as a central feature in auditory object processing.

  18. Human time-frequency acuity beats the Fourier uncertainty principle.

    PubMed

    Oppenheim, Jacob N; Magnasco, Marcelo O

    2013-01-25

    The time-frequency uncertainty principle states that the product of the temporal and frequency extents of a signal cannot be smaller than 1/(4 π). We study human ability to simultaneously judge the frequency and the timing of a sound. Our subjects often exceeded the uncertainty limit, sometimes by more than tenfold, mostly through remarkable timing acuity. Our results establish a lower bound for the nonlinearity and complexity of the algorithms employed by our brains in parsing transient sounds, rule out simple "linear filter" models of early auditory processing, and highlight timing acuity as a central feature in auditory object processing.

  19. Degraded Time-Frequency Acuity to Time-Reversed Notes

    PubMed Central

    Oppenheim, Jacob N.; Isakov, Pavel; Magnasco, Marcelo O.

    2013-01-01

    Time-reversal symmetry breaking is a key feature of many classes of natural sounds, originating in the physics of sound production. While attention has been paid to the response of the auditory system to “natural stimuli,” very few psychophysical tests have been performed. We conduct psychophysical measurements of time-frequency acuity for stylized representations of “natural”-like notes (sharp attack, long decay) and the time-reversed versions of these notes (long attack, sharp decay). Our results demonstrate significantly greater precision, arising from enhanced temporal acuity, for such sounds over their time-reversed versions, without a corresponding decrease in frequency acuity. These data inveigh against models of auditory processing that include tradeoffs between temporal and frequency acuity, at least in the range of notes tested and suggest the existence of statistical priors for notes with a sharp-attack and a long-decay. We are additionally able to calculate a minimal theoretical bound on the sophistication of the nonlinearities in auditory processing. We find that among the best studied classes of nonlinear time-frequency representations, only matching pursuit, spectral derivatives, and reassigned spectrograms are able to satisfy this criterion. PMID:23799012

  20. Electrophysiological Correlates of Vernier Acuity in Human Visual Cortex.

    DTIC Science & Technology

    1984-04-28

    Ia ) VEPs evoked bj vernier offset stimuli couldbe used to estimate 7 LL- psychophysical threshold, b VEP amplitude was affected by interference lines...absolute accuracy. Relative estimate accuracy is judged by the criteria of the estimates being much less than the resolution acuity predicted by anato - mical

  1. Acuity systems dialogue and patient classification system essentials.

    PubMed

    Harper, Kelle; McCully, Crystal

    2007-01-01

    Obtaining resources for quality patient care is a major responsibility of nurse leaders and requires accurate information in the political world of budgeting. Patient classification systems (PCS) assist nurse managers in controlling cost and improving patient care while appropriately using financial resources. This paper communicates acuity systems development, background, flaws, and components while discussing a few tools currently available. It also disseminates the development of a new acuity tool, the Patient Classification System. The PCS tool, developed in a small rural hospital, uses 5 broad concepts: (1) medications, (2) complicated procedures, (3) education, (4) psychosocial issues, and (5) complicated intravenous medications. These concepts embrace a 4-tiered scale that differentiates significant patient characteristics and assists in staffing measures for equality in patient staffing and improving quality of care and performance. Data obtained through use of the PCS can be used by nurse leaders to effectively and objectively lobby for appropriate patient care resources. Two questionnaires distributed to registered nurses on a medical-surgical unit evaluated the nurses' opinion of the 5 concepts and the importance for establishing patient acuity for in-patient care. Interrater reliability among nurses was 87% with the author's acuity tool.

  2. Spatial contrast sensitivity and grating acuity of barn owls.

    PubMed

    Harmening, Wolf M; Nikolay, Petra; Orlowski, Julius; Wagner, Hermann

    2009-07-22

    The eyes of barn owls (Tyto alba pratincola) display very little aberrations, and have thus excellent optical quality. In a series of behavioral experiments, we tested whether this presumably beneficial feature is also reflected at a perceptual level in this species. As fundamental indicators for visual performance, the spatial contrast sensitivity function (CSF) and grating acuity were measured in two barn owls with psychophysical techniques. Stimulus luminance was 2.7 cd/m(2). The CSF found here renders the typical band-limited, inverted U-shaped function, with a low maximum contrast sensitivity of 8-19 at a spatial frequency of 1 cyc/deg. Grating acuity was estimated from the CSF high frequency cut-off and yielded 3.0-3.7 cyc/deg. In a second experiment, in which contrast was held constant and spatial frequency was varied, grating acuity was measured directly (2.6-4.0 cyc/deg). These results put barn owls at the very low end of the visual acuity spectrum of birds, and demonstrate that visual resolution and sensitivity cannot be predicted by optical considerations alone.

  3. On Using Vernier Acuity to Assess Magnocellular Sensitivity

    ERIC Educational Resources Information Center

    Skottun, Bernt C.; Skoyles, John R.

    2010-01-01

    A recent study [Keri, S., & Benedek, G. (2009). Visual pathway deficit in female fragile x premutation carriers: A potential endophenotype. "Brain and Cognition", 69, 291-295] has found Vernier acuity deficiencies together with contrast sensitivity defects consistent with a magnocellular deficit in female fragile x premutation carriers. This may…

  4. Arithmetic Training Does Not Improve Approximate Number System Acuity

    PubMed Central

    Lindskog, Marcus; Winman, Anders; Poom, Leo

    2016-01-01

    The approximate number system (ANS) is thought to support non-symbolic representations of numerical magnitudes in humans. Recently much debate has focused on the causal direction for an observed relation between ANS acuity and arithmetic fluency. Here we investigate if arithmetic training can improve ANS acuity. We show with an experimental training study consisting of six 45-min training sessions that although feedback during arithmetic training improves arithmetic performance substantially, it does not influence ANS acuity. Hence, we find no support for a causal link where symbolic arithmetic training influences ANS acuity. Further, although short-term number memory is likely involved in arithmetic tasks we did not find that short-term memory capacity for numbers, measured by a digit-span test, was effected by arithmetic training. This suggests that the improvement in arithmetic fluency may have occurred independent of short-term memory efficiency, but rather due to long-term memory processes and/or mental calculation strategy development. The theoretical implications of these findings are discussed. PMID:27826270

  5. A Comparison of Patched HOTV Visual Acuity and Photoscreening

    ERIC Educational Resources Information Center

    Leman, Rachel; Clausen, Michelle M.; Bates, Janice; Stark, Lee; Arnold, Koni K.; Arnold, Robert W.

    2006-01-01

    Early detection of significant vision problems in children is a high priority for pediatricians and school nurses. Routine vision screening is a necessary part of that detection and has traditionally involved acuity charts. However, photoscreening in which "red eye" is elicited to show whether each eye is focusing may outperform routine acuity…

  6. THE RELATION BETWEEN VISUAL ACUITY AND BRIGHTNESS DISCRIMINATION

    PubMed Central

    Hendley, Charles D.

    1948-01-01

    1. Visual acuity depends on the brightness contrast between test object and background; and conversely, brightness discrimination depends on the target size. Both functions vary with the brightness of the background. Measurements with rectangular targets of length-width ratio 2 were made over a range of sizes, contrasts, and brightnesses sufficient to determine the relations among these three variables. The rectangles were from 2' to 50' wide; the contrast fraction, ΔI/I, ranged from 0.01 to 40; the background brightness varied from 0.0001 to 2500 millilamberts. 2. When ΔI/I or visual acuity is plotted as a function of brightness the data do, in general, follow Hecht's equation. The departure from a simple photochemical theory which the larger targets show is probably due to changes in the functional retinal mosaic with changing brightness. 3. In general also, the relation between visual acuity and brightness, at selected contrasts, fits Hecht's derivation. At low contrasts, as the brightness is reduced a point is reached at which the test object becomes invisible at any size. 4. No simple relation emerges from the data relating visual acuity to contrast, at set levels of illumination. Over only a very short range are visual acuity and contrast directly related. At high contrasts, visual acuity reaches a maximum, whereas at low visual acuity, ΔI/I reaches a minimum which cannot be passed regardless of size. 5. The shape of the curves relating ΔI/I to brightness is not significantly altered by changing the exposure time. There is some evidence to show that a 3 second exposure of the target is equivalent to two looks of 0.2 second each. 6. In all these studies the thresholds were determined by a frequency of seeing method, and the data have been considered in terms of a quantum theory of threshold seeing. It was found that a threshold response involves between four and eight independent critical events, which are largely independent of size, brightness, and

  7. Initial and noninitial name-letter preferences as obtained through repeated letter rating tasks continue to reflect (different aspects of) self-esteem.

    PubMed

    Hoorens, Vera; Takano, Keisuke; Franck, Erik; Roberts, John E; Raes, Filip

    2015-09-01

    We tested the usefulness of name-letter preference scores as indirect indicators of self-esteem by exploring whether multiple unsupervised self-administrations of letter rating tasks within a short period of time yield useful data. We also examined whether preferences for initials and noninitial name-letters tap different aspects of self-esteem. Participants from a community sample (N = 164; 58 men and 106 women, 17-67 years, Mage = 34.57, SD = 13.28) completed daily letter rating tasks and state self-esteem questionnaires for 7 consecutive days. They also completed a trait self-esteem questionnaire on the first measurement day as well as 6 months later. Preference scores for first-name initials were stronger but more unstable than preference scores for other name-letters. Preferences for first-name initials were primarily associated with directly measured state self-esteem whereas preferences for noninitials were primarily associated with directly measured trait self-esteem even if the latter was measured 6 months later. Thus, we showed that preferences for initials and noninitials are not simply interchangeable. Previous letter rating studies, which almost exclusively used initial preferences, should be interpreted in terms of state rather than trait self-esteem. In future studies, researchers should focus on the name-letter preference that reflects the aspect of self-esteem they wish to address.

  8. Two New Letters by Denning

    NASA Astrophysics Data System (ADS)

    Beech, Martin

    2010-06-01

    Two letters written by W. F. Denning to R. P. Greg in March and April of 1879 that had been tucked into the folds of an 1876 edition of the British Association for the Advancement of Science Reports were recently found at the Carnegie Institution in Washington D.C. The letters are wonderfully preserved, and offer us a snap-shot of the work being performed by a young Denning at the time when his influence in the field of meteor studies was in its ascendency. The contents of these two letters is analyzed and placed within context to Denning's other publications and private life.

  9. Substituted-letter and transposed-letter effects in a masked priming paradigm with French developing readers and dyslexics.

    PubMed

    Lété, Bernard; Fayol, Michel

    2013-01-01

    The aim of the study was to undertake a behavioral investigation of the development of automatic orthographic processing during reading acquisition in French. Following Castles and colleagues' 2007 study (Journal of Experimental Child Psychology, 97, 165-182) and their lexical tuning hypothesis framework, substituted-letter and transposed-letter primes were used in a masked priming paradigm with third graders, fifth graders, adults, and phonological dyslexics matched on reading level with the third graders. No priming effect was found in third graders. In adults, only a transposed-letter priming effect was found; there was no substituted-letter priming effect. Finally, fifth graders and dyslexics showed both substituted-letter and transposed-letter priming effects. Priming effects between the two groups were of the same magnitude after response time (RT) z-score transformation. Taken together, our results show that the pattern of priming effects found by Castles and colleagues in English normal readers emerges later in French normal readers. In other words, language orthographies seem to constrain the tuning of the orthographic system, with an opaque orthography producing faster tuning of orthographic processing than more transparent orthographies because of the high level of reliance on phonological decoding while learning to read.

  10. Dynamic Visual Acuity: a Functionally Relevant Research Tool

    NASA Technical Reports Server (NTRS)

    Peters, Brian T.; Brady, Rachel A.; Miller, Chris A.; Mulavara, Ajitkumar P.; Wood, Scott J.; Cohen, Helen S.; Bloomberg, Jacob J.

    2010-01-01

    Coordinated movements between the eyes and head are required to maintain a stable retinal image during head and body motion. The vestibulo-ocular reflex (VOR) plays a significant role in this gaze control system that functions well for most daily activities. However, certain environmental conditions or interruptions in normal VOR function can lead to inadequate ocular compensation, resulting in oscillopsia, or blurred vision. It is therefore possible to use acuity to determine when the environmental conditions, VOR function, or the combination of the two is not conductive for maintaining clear vision. Over several years we have designed and tested several tests of dynamic visual acuity (DVA). Early tests used the difference between standing and walking acuity to assess decrements in the gaze stabilization system after spaceflight. Supporting ground-based studies measured the responses from patients with bilateral vestibular dysfunction and explored the effects of visual target viewing distance and gait cycle events on walking acuity. Results from these studies show that DVA is affected by spaceflight, is degraded in patients with vestibular dysfunction, changes with target distance, and is not consistent across the gait cycle. We have recently expanded our research to include studies in which seated subjects are translated or rotated passively. Preliminary results from this work indicate that gaze stabilization ability may differ between similar active and passive conditions, may change with age, and can be affected by the location of the visual target with respect to the axis of motion. Use of DVA as a diagnostic tool is becoming more popular but the functional nature of the acuity outcome measure also makes it ideal for identifying conditions that could lead to degraded vision. By doing so, steps can be taken to alter the problematic environments to improve the man-machine interface and optimize performance.

  11. The Complaint Letter and Response.

    ERIC Educational Resources Information Center

    Shukla, P. K.

    1998-01-01

    Describes an assignment in which students write a letter of complaint, and discusses how this assignment aids students in seeing the importance of effective written communication to their daily lives. (SR)

  12. Scoring Guidelines.

    ERIC Educational Resources Information Center

    Tamir, Pinchas; Doran, Rodney L.

    1992-01-01

    Scoring guidelines are given for four forms of the practical skills tests of the Second International Association for the Evaluation of Educational Improvement Science Study conducted in the following countries in the 1980s: (1) Hungary; (2) Japan; (3) Korea; (4) Singapore; (5) Israel; and (6) the United States. (SLD)

  13. THE VISUAL ACUITY AND INTENSITY DISCRIMINATION OF DROSOPHILA

    PubMed Central

    Hecht, Selig; Wald, George

    1934-01-01

    Drosophila possesses an inherited reflex response to a moving visual pattern which can be used to measure its capacity for intensity discrimination and its visual acuity at different illuminations. It is found that these two properties of vision run approximately parallel courses as functions of the prevailing intensity. Visual acuity varies with the logarithm of the intensity in much the same sigmoid way as in man, the bee, and the fiddler crab. The resolving power is very poor at low illuminations and increases at high illuminations. The maximum visual acuity is 0.0018, which is 1/1000 of the maximum of the human eye and 1/10 that of the bee. The intensity discrimination of Drosophila is also extremely poor, even at its best. At low illuminations for two intensities to be recognized as different, the higher must be nearly 100 times the lower. This ratio decreases as the intensity increases, and reaches a minimum of 2.5 which is maintained at the highest intensities. The minimum value of ΔI/I for Drosophila is 1.5, which is to be compared with 0.25 for the bee and 0.006 for man. An explanation of the variation of visual acuity with illumination is given in terms of the variation in number of elements functional in the retinal mosaic at different intensities, this being dependent on the general statistical distribution of thresholds in the ommatidial population. Visual acuity is thus determined by the integral form of this distribution and corresponds to the total number of elements functional. The idea that intensity discrimination is determined by the differential form of this distribution—that is, that it depends on the rate of entrance of functional elements with intensity—is shown to be untenable in the light of the correspondence of the two visual functions. It is suggested that, like visual acuity, intensity discrimination may also have to be considered as a function of the total number of elements active at a given intensity. PMID:19872798

  14. Lumbar position sense acuity during an electrical shock stressor

    PubMed Central

    Hjortskov, Nis; Hye-Knudsen, Christian; Fallentin, Nils

    2005-01-01

    Background Optimal motor control of the spine depends on proprioceptive input as a prerequisite for co-ordination and the stability of the spine. Muscle spindles are known to play an important role in proprioception. Animal experiments suggest that an increase in sympathetic outflow can depress muscle spindle sensitivity. As the muscle spindle may be influenced by sympathetic modulation, we hypothesized that a state of high sympathetic activity as during mental stress would affect the proprioceptive output from the muscle spindles in the back muscles leading to alterations in proprioception and position sense acuity. The aim was to investigate the effect of mental stress, in this study the response to an electrical shock stressor, on position sense acuity in the rotational axis of the lumbar spine. Methods Passive and active position sense acuity in the rotational plane of the lumbar spine was investigated in the presence and absence of an electrical shock stressor in 14 healthy participants. An electrical shock-threat stressor lasting for approximately 12 minutes was used as imposed stressor to build up a strong anticipatory arousal: The participants were told that they were going to receive 8 painful electrical shocks however the participants never received the shocks. To quantify the level of physiological arousal and the level of sympathetic outflow continuous beat-to-beat changes in heart rate (beats*min-1) and systolic, diastolic and mean arterial blood pressure (mmHg) were measured. To quantify position sense acuity absolute error (AE) expressed in degrees was measured. Two-way analysis of variance with repeated measurements (subjects as random factor and treatments as fixed factors) was used to compare the different treatments. Results Significant increases were observed in systolic blood pressure, diastolic blood pressure, and heart rate during the stress sessions indicating elevated sympathetic activity (15, 14 and 10%, respectively). Despite pronounced

  15. Letter Writing: A Tool for Counselor Educators

    ERIC Educational Resources Information Center

    Hoffman, Rachel M.

    2008-01-01

    Letter writing is an integral component of narrative therapy practice. In addition to the benefits of letter writing in counseling practice, letter writing may hold interesting possibilities for use in counselor education. This article provides a brief review of the benefits of letter writing in counseling practice and discusses the potential use…

  16. Embedded Picture Mnemonics to Learn Letters

    ERIC Educational Resources Information Center

    Shmidman, Adina; Ehri, Linnea

    2010-01-01

    Can embedded mnemonics ease the task of learning a foreign alphabet? English-speaking preschoolers (N = 36, M = 5;2 years) were taught 10 Hebrew letter-sound relations. Experimental letters were learned with mnemonics that embedded letter shapes in drawings of objects whose shapes resembled the letters and whose English names began with the…

  17. Essay: Physical Review Letters; Sam Goudsmit's Vision.

    PubMed

    Adair, Robert K

    2008-01-18

    Sam Goudsmit implemented his vision of converting the Letters section of Physical Review into a distinct journal fifty years ago. Physical Review Letters was designed to publish "only papers that really deserve rapid communication." The new journal became so successful with physicists throughout the world that Physical Review Letters now publishes 3500 Letters per year.

  18. Business Letter Writing: English, French, and Japanese.

    ERIC Educational Resources Information Center

    Jenkins, Susan; Hinds, John

    1987-01-01

    Examination of business letters in English, French, and Japanese, focusing on prescriptive accounts in the respective languages, found that, despite amazingly similar surface characteristics, American business letters were reader-oriented, French business letters were writer-oriented, and Japanese business letters were oriented to the space…

  19. Higher-order aberrations and best-corrected visual acuity in Native American children with a high prevalence of astigmatism

    PubMed Central

    Miller, Joseph M.; Harvey, Erin M.; Schwiegerling, Jim

    2016-01-01

    Purpose To determine whether higher-order aberrations (HOAs) in children from a highly astigmatic population differ from population norms and whether HOAs are associated with astigmatism and reduced best-corrected visual acuity. Methods Subjects were 218 Tohono O’odham Native American children 5–9 years of age. Noncycloplegic HOA measurements were obtained with a handheld Shack-Hartmann sensor (SHS). Signed (z06s to z14s) and unsigned (z06u to z14u) wavefront aberration Zernike coefficients Z(3,−3) to Z(4,4) were rescaled for a 4 mm diameter pupil and compared to adult population norms. Cycloplegic refraction and best-corrected logMAR letter visual acuity (BCVA) were also measured. Regression analyses assessed the contribution of astigmatism (J0) and HOAs to BCVA. Results The mean root-mean-square (RMS) HOA of 0.191 ± 0.072 μm was significantly greater than population norms (0.100 ± 0.044 μm. All unsigned HOA coefficients (z06u to z14u) and all signed coefficients except z09s, z10s, and z11s were significantly larger than population norms. Decreased BCVA was associated with astigmatism (J0) and spherical aberration (z12u) but not RMS coma, with the effect of J0 about 4 times as great as z12u. Conclusions Tohono O’odham children show elevated HOAs compared to population norms. Astigmatism and unsigned spherical aberration are associated with decreased acuity, but the effects of spherical aberration are minimal and not clinically significant. PMID:26239206

  20. Assessment of Visual Acuity in Relation to Central Nervous System Activation in Children with Mental Retardation.

    ERIC Educational Resources Information Center

    Jacobsen, Karl; Grottland, Havar; Flaten, Magne Arve

    2001-01-01

    Assessment of visual acuity, using Teller Acuity Cards, was combined with observations of behavioral state to indicate central nervous system activation in 24 individuals with mental retardation. Results indicate that forced-choice preferential-looking technique can be used to test visual acuity in this population unless the participant is drowsy.…

  1. Influence of loupes and age on the near visual acuity of practicing dentists

    NASA Astrophysics Data System (ADS)

    Eichenberger, Martina; Perrin, Philippe; Neuhaus, Klaus W.; Bringolf, Ueli; Lussi, Adrian

    2011-03-01

    We evaluated the near visual acuity of 40 dentists and its improvement by using different magnification devices. The acuity was tested with miniaturized E-optotype tests on a negatoscope under the following conditions: 1. natural visual acuity, 300 mm; 2. single lens loupe, 2×, 250 mm; 3. Galilean loupe, 2.5×, 380 mm; and 4. Keplerian loupe, 4.3×, 400 mm. In part 1, the influence of the magnification devices was investigated for all dentists. The Keplerian loupe obtained the highest visual acuity (4.64), followed by the Galilean loupe (2.43), the single lens loupe (1.42), and natural visual acuity (1.19). For part 2, the dentists were classified according to their age (=40 years). The younger dentists' group achieved a significantly higher visual acuity with all magnification devices (p<0.001). For part 3, the dentists were grouped according to their natural visual acuity. The group with the higher natural visual acuity achieved significantly higher visual acuity with all magnification devices than did the group of dentists with the lower natural visual acuity (p<0.01). It can be concluded that near visual acuity varies highly between individuals and decreases during the lifetime. Independent of age or natural vision, visual acuity can be significantly improved by using magnification devices.

  2. Evaluation of visual acuity with Gen 3 night vision goggles

    NASA Technical Reports Server (NTRS)

    Bradley, Arthur; Kaiser, Mary K.

    1994-01-01

    Using laboratory simulations, visual performance was measured at luminance and night vision imaging system (NVIS) radiance levels typically encountered in the natural nocturnal environment. Comparisons were made between visual performance with unaided vision and that observed with subjects using image intensification. An Amplified Night Vision Imaging System (ANVIS6) binocular image intensifier was used. Light levels available in the experiments (using video display technology and filters) were matched to those of reflecting objects illuminated by representative night-sky conditions (e.g., full moon, starlight). Results show that as expected, the precipitous decline in foveal acuity experienced with decreasing mesopic luminance levels is effectively shifted to much lower light levels by use of an image intensification system. The benefits of intensification are most pronounced foveally, but still observable at 20 deg eccentricity. Binocularity provides a small improvement in visual acuity under both intensified and unintensified conditions.

  3. Ultrafine spatial acuity of blind expert human echolocators

    PubMed Central

    Puri, Amrita; Whitney, David

    2013-01-01

    Echolocating organisms represent their external environment using reflected auditory information from emitted vocalizations. This ability, long known in various non-human species, has also been documented in some blind humans as an aid to navigation, as well as object detection and coarse localization. Surprisingly, our understanding of the basic acuity attainable by practitioners—the most fundamental underpinning of echoic spatial perception—remains crude. We found that experts were able to discriminate horizontal offsets of stimuli as small as ~1.2° auditory angle in the frontomedial plane, a resolution approaching the maximum measured precision of human spatial hearing and comparable to that found in bats performing similar tasks. Furthermore, we found a strong correlation between echolocation acuity and age of blindness onset. This first measure of functional spatial resolution in a population of expert echolocators demonstrates precision comparable to that found in the visual periphery of sighted individuals. PMID:22101568

  4. Heterogeneity of failure of visual acuity in Graves' disease.

    PubMed Central

    Sachdev, Y.; Chatterji, J. C.; Sharma, R. C.

    1979-01-01

    The eye manifestations of Graves' disease are usually mild and self-limiting. Occasionally they follow a progressive course leading to visual loss and total blindness. The ocular manifestations bear no relationship to the metabolic state and may appear before, during or after onset of thyrotoxicosis. Characteristically they become evident at about the time of onset of hypermetabolism. Various factors responsible for the failure of visual acuity are discussed with case illustrations. PMID:314108

  5. Eye size and visual acuity influence vestibular anatomy in mammals.

    PubMed

    Kemp, Addison D; Christopher Kirk, E

    2014-04-01

    The semicircular canals of the inner ear detect head rotations and trigger compensatory movements that stabilize gaze and help maintain visual fixation. Mammals with large eyes and high visual acuity require precise gaze stabilization mechanisms because they experience diminished visual functionality at low thresholds of uncompensated motion. Because semicircular canal radius of curvature is a primary determinant of canal sensitivity, species with large canal radii are expected to be capable of more precise gaze stabilization than species with small canal radii. Here, we examine the relationship between mean semicircular canal radius of curvature, eye size, and visual acuity in a large sample of mammals. Our results demonstrate that eye size and visual acuity both explain a significant proportion of the variance in mean canal radius of curvature after statistically controlling for the effects of body mass and phylogeny. These findings suggest that variation in mean semicircular canal radius of curvature among mammals is partly the result of selection for improved gaze stabilization in species with large eyes and acute vision. Our results also provide a possible functional explanation for the small semicircular canal radii of fossorial mammals and plesiadapiforms.

  6. Effects of Horizontal Acceleration on Human Visual Acuity and Stereopsis

    PubMed Central

    Horng, Chi-Ting; Hsieh, Yih-Shou; Tsai, Ming-Ling; Chang, Wei-Kang; Yang, Tzu-Hung; Yauan, Chien-Han; Wang, Chih-Hung; Kuo, Wu-Hsien; Wu, Yi-Chang

    2015-01-01

    The effect of horizontal acceleration on human visual acuity and stereopsis is demonstrated in this study. Twenty participants (mean age 22.6 years) were enrolled in the experiment. Acceleration from two different directions was performed at the Taiwan High-Speed Rail Laboratory. Gx and Gy (< and >0.1 g) were produced on an accelerating platform where the subjects stood. The visual acuity and stereopsis of the right eye were measured before and during the acceleration. Acceleration <0.1 g in the X- or Y-axis did not affect dynamic vision and stereopsis. Vision decreased (mean from 0.02 logMAR to 0.25 logMAR) and stereopsis declined significantly (mean from 40 s to 60.2 s of arc) when Gx > 0.1 g. Visual acuity worsened (mean from 0.02 logMAR to 0.19 logMAR) and poor stereopsis was noted (mean from 40 s to 50.2 s of arc) when Gy > 0.1 g. The effect of acceleration from the X-axis on the visual system was higher than that from the Y-axis. During acceleration, most subjects complained of ocular strain when reading. To our knowledge, this study is the first to report the exact levels of visual function loss during Gx and Gy. PMID:25607601

  7. Effects of horizontal acceleration on human visual acuity and stereopsis.

    PubMed

    Horng, Chi-Ting; Hsieh, Yih-Shou; Tsai, Ming-Ling; Chang, Wei-Kang; Yang, Tzu-Hung; Yauan, Chien-Han; Wang, Chih-Hung; Kuo, Wu-Hsien; Wu, Yi-Chang

    2015-01-19

    The effect of horizontal acceleration on human visual acuity and stereopsis is demonstrated in this study. Twenty participants (mean age 22.6 years) were enrolled in the experiment. Acceleration from two different directions was performed at the Taiwan High-Speed Rail Laboratory. Gx and Gy (< and >0.1 g) were produced on an accelerating platform where the subjects stood. The visual acuity and stereopsis of the right eye were measured before and during the acceleration. Acceleration <0.1 g in the X- or Y-axis did not affect dynamic vision and stereopsis. Vision decreased (mean from 0.02 logMAR to 0.25 logMAR) and stereopsis declined significantly (mean from 40 s to 60.2 s of arc) when Gx > 0.1 g. Visual acuity worsened (mean from 0.02 logMAR to 0.19 logMAR) and poor stereopsis was noted (mean from 40 s to 50.2 s of arc) when Gy > 0.1 g. The effect of acceleration from the X-axis on the visual system was higher than that from the Y-axis. During acceleration, most subjects complained of ocular strain when reading. To our knowledge, this study is the first to report the exact levels of visual function loss during Gx and Gy.

  8. Effects of Letter-Identification Training on Letter Naming in Prereading Children

    ERIC Educational Resources Information Center

    Hayashi, Yusuke; Schmidt, Anna C.; Saunders, Kathryn J.

    2013-01-01

    Three prereading children who named 0 to 3 of 20 targeted letters were taught to select the 20 printed letters when they heard spoken letter names. For all participants, letter-identification training resulted in naming for the majority of letters.

  9. Sporadic Visual Acuity Loss in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT)

    PubMed Central

    Kim, Benjamin J.; Ying, Gui-Shuang; Huang, Jiayan; Levy, Nicole E.; Maguire, Maureen G.

    2014-01-01

    Purpose To evaluate transient, large visual acuity (VA) decreases, termed sporadic vision loss, during anti-vascular endothelial growth factor treatment for neovascular age-related macular degeneration (AMD). Design Cohort within a randomized clinical trial. Methods Setting Comparison of AMD Treatments Trials (CATT). Study Population 1185 CATT patients. Main Outcome Measures incidence of sporadic vision loss and odds ratio (OR) for association with patient and ocular factors. Sporadic vision loss was a decline of ≥ 15 letters from the previous visit, followed by a return at the next visit to no more than 5 letters worse than the visit before the VA loss. Results There were 143 sporadic vision loss events in 122/1185 (10.3%) patients. Mean VA at two years for those with and without sporadic vision loss was 58.5 (~20/63) and 68.4 (~20/40) letters, respectively (P < 0.001). Among patients treated pro re nata, no injection was given for 27.6% (27/98) of sporadic vision loss events. Multivariate analysis demonstrated that baseline predictors for sporadic vision loss included worse baseline VA (OR 2.92, 95%CI:1.65–5.17 for ≤ 20/200 compared with ≥ 20/40), scar (OR 2.21, 95%CI:1.22–4.01), intraretinal foveal fluid on optical coherence tomography (OR 1.80, 95%CI:1.11–2.91), and medical history of anxiety (OR 1.90, 95%CI:1.12–3.24) and syncope (OR 2.75, 95%CI:1.45–5.22). Refraction decreased the likelihood of sporadic vision loss (OR 0.62, 95%CI:0.42–0.91). Conclusions Approximately 10% of CATT patients had sporadic vision loss. Baseline predictors included AMD-related factors and factors independent of AMD. These data are relevant for clinicians in practice and those involved in clinical trials. PMID:24727261

  10. Improvement of tactile roughness discrimination acuity correlates with perception of improved hand function in patients after hand surgery

    PubMed Central

    Fujimoto, Shuhei; Kon, Noriko

    2016-01-01

    [Purpose] The purpose of this study was to elucidate how well patients’ perceptions related to the improvements in their hand function during hospitalization. [Subjects] Sixteen patients who were hospitalized after hand surgery. [Methods] Using the Japanese Society for Surgery of the Hand edition of the Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire; tactile roughness discrimination acuity, motor imagery, motor function, sensory function, and pain of the upper limb were assessed at admission and discharge. Spearman’s rank-order correlation coefficients were calculated using the differences in all assessment items at admission and discharge. A multiple regression analysis (stepwise method) was performed to investigate factors that correlated with improvements in Quick-Disabilities of the Arm, Shoulder, and Hand scores. [Results] The improvement of tactile roughness discrimination acuity was significantly associated with patient perception of improved hand function. [Conclusion] The results suggest that an improvement in tactile roughness discrimination acuity was most strongly correlated with patient perception of improved hand function. PMID:27190473

  11. Distance stereo acuity improvement in intermittent exotropic patients following strabismus surgery.

    PubMed

    O'Neal, T D; Rosenbaum, A L; Stathacopoulos, R A

    1995-01-01

    To determine whether distance stereo acuity improved following strabismus surgery in patients with intermittent exotropia, we tested 20 patients (5 to 87 years old) preoperatively and postoperatively using the Mentor BVAT II Video acuity tester (Santa Barbara, Calif) and binocular visual system. Acuity improved in 75% as assessed by contour circles and in 45% as assessed by random dot E tests at distance. Our results suggest that surgical realignment of intermittent exotropia restores distance stereo acuity. We conclude that measuring distance stereo acuity offers valuable information in the evaluation of the intermittent exotropic patient.

  12. Predicting Growth of Nonword Reading and Letter-Sound Knowledge Following Rime- And Phoneme-Based Teaching

    ERIC Educational Resources Information Center

    Savage, Robert; Carless, Sue

    2004-01-01

    The present study sought to extend a recent study by Savage, Carless and Stuart, by looking at the pre-test phonological skills that predicted improvements in letter-sound knowledge and nonword reading. Results showed overall that phoneme manipulation predicted improvements in nonword reading and letter-sound knowledge even when pre-test scores on…

  13. Influence of adaptive-optics ocular aberration correction on visual acuity at different luminances and contrast polarities.

    PubMed

    Marcos, Susana; Sawides, Lucie; Gambra, Enrique; Dorronsoro, Carlos

    2008-10-06

    We evaluated the visual benefit of correcting astigmatism and high-order aberrations with adaptive optics (AO) on visual acuity (VA) measured at 7 different luminances (ranging from 0.8 to 50 cd/m(2)) and two contrast polarities (black letters on white background, BoW, and white letters on black background, WoB) on 7 subjects. For the BoW condition, VA increased with background luminance in both natural and AO-corrected conditions, and there was a benefit of AO correction at all luminances (by a factor of 1.29 on average across luminances). For WoB VA increased with foreground luminance but decreased for the highest luminances. In this reversed polarity condition AO correction increased VA by a factor of 1.13 on average and did not produce a visual benefit at high luminances. The improvement of VA (averaged across conditions) was significantly correlated (p = 0.04) with the amount of corrected aberrations (in terms of Strehl ratio). The improved performance with WoB targets with respect to BoW targets is decreased when correcting aberrations, suggesting a role of ocular aberrations in the differences in visual performance between contrast polarities.

  14. Development of a Reading Accessibility Index Using the MNREAD Acuity Chart

    PubMed Central

    Calabrèse, Aurélie; Owsley, Cynthia; McGwin, Gerald; Legge, Gordon E.

    2017-01-01

    IMPORTANCE We define a Reading Accessibility Index for evaluating reading in individuals with normal and low vision. OBJECTIVE To compare the Reading Accessibility Index with data from the Impact of Cataracts on Mobility (ICOM) study. DESIGN, SETTING, AND PARTICIPANTS This investigation was a secondary data analysis from the ICOM study performed between July 1, 2014, and September 20, 2015, at 12 eye clinics in Alabama from October 1, 1994, through March 31, 1996. Participants were 321 adults with cataract (n = 92), pseudophakia (n = 131), or natural crystalline lenses without cataract (n = 98). MAIN OUTCOMES AND MEASURES The Reading Accessibility Index (hereafter referred to using the abbreviation ACC for the first 3 letters of Accessibility) is defined as an individual’s mean reading speed measured across the 10 largest print sizes on the MNREAD Acuity Chart (Precision Vision) (0.4–1.3 logarithm of the minimum angle of resolution at 40 cm), normalized by 200 words per minute, which was the mean value for a group of 365 normally sighted young adults. The ACC is a single-value measure that captures an individual’s range of accessible print sizes and reading fluency within this range. RESULTS The study cohort comprised 321 participants. Their age range was 55 to 85 years, and 157 (48.9%) were female. The ACCs for the ICOM study participants ranged from 0.19 to 1.33, where 1.00 is the mean value for normally sighted young adults. The ACC for the cataract group (mean [SD], 0.65 [0.18]) was significantly lower than that for the pseudophakia group (mean [SD], 0.77 [0.16]) and the control group (mean [SD], 0.76 [0.19]) (P < .001 for both). The correlation between the ACC and Early Treatment Diabetic Retinopathy Study visual acuity (r = −0.22) and Pelli-Robson contrast sensitivity (r = 0.20) was weaker than that with a reading-related measure of instrumental activities of daily living (r = −0.60) (P < .001 for both). CONCLUSIONS AND RELEVANCE The ACC represents

  15. The Harvard Education Letter, 1996.

    ERIC Educational Resources Information Center

    Miller, Edward Ed.; Graves-Desai, Kelly, Ed.; Maloney, Karen, Ed.

    1996-01-01

    This document is comprised of volume 12 of the Harvard Education Letter, published bimonthly and addressing current issues in elementary-secondary education. Articles in this volume include the following: (1) January-February--"Early Reports From Kentucky on Cash Rewards for 'Successful' Schools Reveal Many Problems" (Miller), "New…

  16. The Harvard Education Letter, 1995.

    ERIC Educational Resources Information Center

    Miller, Edward, Ed.

    1995-01-01

    This document is comprised of volume 11 of the Harvard Education Letter, published bimonthly and addressing current issues in elementary and secondary education. Articles in the volume's six issues are: (1) January-February--"The Old Model of Staff Development Survives in a World Where Everything Else Has Changed" (Miller), "Giving Voice to Our…

  17. Curriculum Vitae and Related Letters.

    ERIC Educational Resources Information Center

    Peterson, Sharyl Bender

    This booklet, which was developed by a college career center, explains the purpose of and procedures for writing curriculum vitae (CV) and related letters. The following topics are covered: when a CV is appropriate, points to consider when writing a CV, items usually included, possible sections to include in a CV, and steps in writing cover…

  18. The Harvard Education Letter, 1997.

    ERIC Educational Resources Information Center

    Graves-Desai, Kelly, Ed.; Maloney, Karen, Ed.

    1997-01-01

    This document is comprised of volume 13 of the Harvard Education Letter, published bimonthly and addressing current issues in elementary and secondary education. Articles in the six issues of this volume include: (1) January-February --"Making Detracking Work" (Lynn and Wheelock), "Developing a Culture of High Expectations for…

  19. Letter to the next President

    ERIC Educational Resources Information Center

    Rotherham, Andrew J.; Mikuta, Julie; Freeland, Julia

    2008-01-01

    This article takes the form of a letter to the 44th president of the United States, urging the president to pursue an aggressive agenda to improve teacher quality. The authors assert that because teacher quality is the single most important factor shown to impact student outcomes, the next administration must dedicate resources to human capital…

  20. "The Scarlet Letter". [Lesson Plan].

    ERIC Educational Resources Information Center

    Discovery Communications, Inc., Bethesda, MD.

    Based on Nathaniel Hawthorne's novel "The Scarlet Letter," this lesson plan presents activities designed to help students understand that the ending of a novel does not resolve all of the questions that may occur to readers; and that readers may imagine characters living out their lives beyond the ending the author gave to a novel. The main…

  1. The Harvard Education Letter, 1998.

    ERIC Educational Resources Information Center

    Graves-Desai, Kelly, Ed.; Eaton, Susan, Ed.; Walser, Nancy, Ed.

    1998-01-01

    This document is comprised of volume 14 of the Harvard Education Letter, published bimonthly and addressing current issues in elementary and secondary education. Articles in the six issues of this volume include the following: (1) January-February--"Multi-Age Classrooms: An Age-Old Grouping Method Is Still Evolving" (Walser), "Teachers Wanted:…

  2. Resource Letter RC-1: Cosmology

    ERIC Educational Resources Information Center

    Ryan, Michael P., Jr.; Shepley, L. C.

    1976-01-01

    This is one of a series of resource letters on different topics intended to guide college physicists, astronomers, and other scientists to some of the literature and other teaching aids that may help improve course content in specified fields. (Author/CP)

  3. Resource Letter N-1: Nanotechnology

    NASA Astrophysics Data System (ADS)

    Cela, Devin; Dresselhaus, Mildred; Helen Zeng, Tingying; Terrones, Mauricio; Souza Filho, Antonio G.; Ferreira, Odair P.

    2014-01-01

    This Resource Letter provides a guide to the literature on Nanotechnology. Journal articles, books, websites, and other documents are cited on the following topics: attributes of various types of nanomaterials, nanotechnology in the context of different academic fields, and the effects of nanotechnology on society.

  4. Resumes, Applications, and Cover Letters

    ERIC Educational Resources Information Center

    Crosby, Olivia

    2009-01-01

    Good resumes, applications, and cover letters broadcast one's abilities. They tell employers how one's qualifications match a job's responsibilities. If these critical preliminaries are constructed well, one has a better chance of landing interviews--and, eventually, a job. This article provides some guidelines for creating resumes and cover…

  5. Letters from a Nightingale nurse.

    PubMed

    Denny, E

    1996-01-01

    Mary Cadbury was one of six daughters in a wealthy Birmingham family, all of whom took up professional or unpaid philanthropic work. In 1873 Mary began nurse training at the Nightingale School, St Thomas's Hospital, and regularly sent letters to family and friends, which provide a graphic account of the experience of a nurse in the latter half of the nineteenth century.

  6. Letters of Reprimand: The Important Questions.

    ERIC Educational Resources Information Center

    Zirkel, Perry A.; Gluckman, Ivan B.

    1986-01-01

    Outlines two legal cases involving letters of reprimand written by administrators and put in teachers' files. Shows how in these cases the letters did not constitute defamation or a violation of First or Fourteenth Amendment rights. (MD)

  7. Evaluation of vernier acuity near healed retinal laser lesions

    NASA Astrophysics Data System (ADS)

    Schmeisser, Elmar T.

    1997-05-01

    Seven Cynomolgus fasciculata who had graded laser lesions placed in own eye 6 years previously were evaluated for their vernier acuity by electrophysiologic recording techniques. In these experiments, 95 percent contrast vernier acuity targets were presented at high luminance levels to anesthetized primates. Visual evoked potentials were recorded by conventional means form scalp electrodes through hospital grade amplifiers. All animal testing was performed under IACUC approved protocols. The single q-switched pulses form a neodymium-YAG laser had produced lesions of 4 types: no visible change, minimal visible lesions, 'white dot' lesions and 'red dot' lesions in the eye at the time of placement. Single exposures had been made in four locations: 5 degrees superior, inferior and temporal to the fovea, and one foveally. Vernier recording proved somewhat successful in smaller animals with less than contained retinal hemorrhage lesions in the fovea. Initial analyses demonstrated a significant decrease of the pattern response signal/noise in the experimental eye overall, and an apparent relative loss of vernier signal in some lesioned eyes. Animals with the more severe lesions have somewhat degraded small patten responses and no recordable vernier response. Apparent lesser losses produced less effect.

  8. Influence of intraocular lens subsurface nanoglistenings on functional visual acuity

    PubMed Central

    Miyata, Kazunori; Hayashidera, Takeshi; Iida, Masaharu; Takada, Keita; Minami, Keiichiro; Oshika, Tetsuro

    2017-01-01

    To investigate the influence of intraocular lens subsurface nanoglistenings (SSNGs) on functional visual acuity (FVA), thirty-nine eyes of 29 patients were examined in this study. The SSNG group comprised 19 eyes of 14 patients (75.7± 5.4 years, mean ± standard deviation), and the control group comprised 20 eyes of 15 patients (73.6 ± 6.5 years). The SSNGs were diagnosed on the basis of the typical whitish IOL appearance upon slit-lamp examination and results of densitometry regarding surface light scattering using Scheimpflug images. The FVA measurement system (AS-28; Kowa, Aichi, Japan) was used to examine changes in continuous visual acuity (VA) over time, and visual function parameters such as FVA, visual maintenance ratio (VMR), maximum VA, minimum VA, standard deviation of VA, and number of blinks were assessed. The results were compared between the SSNG and control groups, and correlations of FVA parameters with the intensity of surface light scattering, time after surgery, and age were also evaluated. There were significant differences in VMR (P = 0.035) and standard deviation of VAs (P = 0.031) between the two groups, although no significant differences were found in baseline VA, FVA, maximum VA, minimum VA, and number of blinks. None of the FVA parameters showed any significant correlations with the intensity of surface light scattering, time after surgery, or age. There is a possibility that VA is unstable during a continuous gazing task in patients with SSNGs. PMID:28328997

  9. Distinct eye movement patterns enhance dynamic visual acuity

    PubMed Central

    Palidis, Dimitrios J.; Wyder-Hodge, Pearson A.; Fooken, Jolande; Spering, Miriam

    2017-01-01

    Dynamic visual acuity (DVA) is the ability to resolve fine spatial detail in dynamic objects during head fixation, or in static objects during head or body rotation. This ability is important for many activities such as ball sports, and a close relation has been shown between DVA and sports expertise. DVA tasks involve eye movements, yet, it is unclear which aspects of eye movements contribute to successful performance. Here we examined the relation between DVA and the kinematics of smooth pursuit and saccadic eye movements in a cohort of 23 varsity baseball players. In a computerized dynamic-object DVA test, observers reported the location of the gap in a small Landolt-C ring moving at various speeds while eye movements were recorded. Smooth pursuit kinematics—eye latency, acceleration, velocity gain, position error—and the direction and amplitude of saccadic eye movements were linked to perceptual performance. Results reveal that distinct eye movement patterns—minimizing eye position error, tracking smoothly, and inhibiting reverse saccades—were related to dynamic visual acuity. The close link between eye movement quality and DVA performance has important implications for the development of perceptual training programs to improve DVA. PMID:28187157

  10. Changes in brain morphology in albinism reflect reduced visual acuity.

    PubMed

    Bridge, Holly; von dem Hagen, Elisabeth A H; Davies, George; Chambers, Claire; Gouws, Andre; Hoffmann, Michael; Morland, Antony B

    2014-07-01

    Albinism, in humans and many animal species, has a major impact on the visual system, leading to reduced acuity, lack of binocular function and nystagmus. In addition to the lack of a foveal pit, there is a disruption to the routing of the nerve fibers crossing at the optic chiasm, resulting in excessive crossing of fibers to the contralateral hemisphere. However, very little is known about the effect of this misrouting on the structure of the post-chiasmatic visual pathway, and the occipital lobes in particular. Whole-brain analyses of cortical thickness in a large cohort of subjects with albinism showed an increase in cortical thickness, relative to control subjects, particularly in posterior V1, corresponding to the foveal representation. Furthermore, mean cortical thickness across entire V1 was significantly greater in these subjects compared to controls and negatively correlated with visual acuity in albinism. Additionally, the group with albinism showed decreased gyrification in the left ventral occipital lobe. While the increase in cortical thickness in V1, also found in congenitally blind subjects, has been interpreted to reflect a lack of pruning, the decreased gyrification in the ventral extrastriate cortex may reflect the reduced input to the foveal regions of the ventral visual stream.

  11. 7 CFR 1773.33 - Management letter.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 12 2011-01-01 2011-01-01 false Management letter. 1773.33 Section 1773.33... AGRICULTURE (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Reporting Requirements § 1773.33 Management letter. The CPA must prepare a management letter that includes, at a minimum, comments on: (a)...

  12. 7 CFR 1773.33 - Management letter.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Management letter. 1773.33 Section 1773.33... AGRICULTURE (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Reporting Requirements § 1773.33 Management letter. The CPA must prepare a management letter that includes, at a minimum, comments on: (a)...

  13. 24 CFR 200.1505 - Warning letter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... URBAN DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Multifamily Accelerated Processing (MAP): MAP... letter, which specifies problems or violations identified by HUD, to a MAP lender. (b) Effect of warning letter. The warning letter: (1) Does not suspend a lender's MAP privileges; (2) May impose a higher...

  14. 24 CFR 200.1505 - Warning letter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... URBAN DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Multifamily Accelerated Processing (MAP): MAP... letter, which specifies problems or violations identified by HUD, to a MAP lender. (b) Effect of warning letter. The warning letter: (1) Does not suspend a lender's MAP privileges; (2) May impose a higher...

  15. 24 CFR 200.1505 - Warning letter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... URBAN DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Multifamily Accelerated Processing (MAP): MAP... letter, which specifies problems or violations identified by HUD, to a MAP lender. (b) Effect of warning letter. The warning letter: (1) Does not suspend a lender's MAP privileges; (2) May impose a higher...

  16. 24 CFR 200.1505 - Warning letter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... URBAN DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Multifamily Accelerated Processing (MAP): MAP... letter, which specifies problems or violations identified by HUD, to a MAP lender. (b) Effect of warning letter. The warning letter: (1) Does not suspend a lender's MAP privileges; (2) May impose a higher...

  17. 24 CFR 200.1505 - Warning letter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... URBAN DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Multifamily Accelerated Processing (MAP): MAP... letter, which specifies problems or violations identified by HUD, to a MAP lender. (b) Effect of warning letter. The warning letter: (1) Does not suspend a lender's MAP privileges; (2) May impose a higher...

  18. 7 CFR 1773.33 - Management letter.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Management letter. 1773.33 Section 1773.33 Agriculture... (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Reporting Requirements § 1773.33 Management letter. The CPA must prepare a management letter that includes, at a minimum, comments on: (a) Audit procedures....

  19. 7 CFR 1773.33 - Management letter.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Management letter. 1773.33 Section 1773.33... AGRICULTURE (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Reporting Requirements § 1773.33 Management letter. The CPA must prepare a management letter that includes, at a minimum, comments on: (a)...

  20. 7 CFR 1773.33 - Management letter.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Management letter. 1773.33 Section 1773.33... AGRICULTURE (CONTINUED) POLICY ON AUDITS OF RUS BORROWERS RUS Reporting Requirements § 1773.33 Management letter. The CPA must prepare a management letter that includes, at a minimum, comments on: (a)...

  1. Making Routine Letters Have Positive Effects.

    ERIC Educational Resources Information Center

    Walsh, S. M.

    While few business people dispute the importance of carefully crafting persuasive, demanding, conciliatory, and bad-news letters, the regular flow of routine communications receives very little meaningful consideration or scrutiny. These routine communications (letters, inquiries, requests, collection letters, complaints, confirmations,…

  2. Beyond Zebra: Preschoolers' Knowledge about Letters.

    ERIC Educational Resources Information Center

    Treiman, Rebecca; Richmond-Welty, E. Daylene; Tincoff, Ruth

    1997-01-01

    Argues that an important type of child knowledge about letters is knowledge of the phonological structure of the letters' names in English. Concludes that learning the alphabet forms the basis for generalizations about the structure of letter names. (22 references) (Author/CK)

  3. 48 CFR 3016.603 - Letter contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Letter contracts. 3016.603... ACQUISITION REGULATION (HSAR) CONTRACT METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts 3016.603 Letter contracts....

  4. 48 CFR 3416.603 - Letter contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Letter contracts. 3416.603... CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts 3416.603 Letter contracts....

  5. Are Letter Detection and Proofreading Tasks Equivalent?

    ERIC Educational Resources Information Center

    Saint-Aubin, Jean; Losier, Marie-Claire; Roy, Macha; Lawrence, Mike

    2015-01-01

    When readers search for misspellings in a proofreading task or for a letter in a letter detection task, they are more likely to omit function words than content words. However, with misspelled words, previous findings for the letter detection task were mixed. In two experiments, the authors tested the functional equivalence of both tasks. Results…

  6. 49 CFR 107.309 - Warning letters.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Warning letters. 107.309 Section 107.309... PROGRAM PROCEDURES Enforcement Compliance Orders and Civil Penalties § 107.309 Warning letters. (a) The Associate Administrator may issue a warning letter to any person whom the Associate Administrator...

  7. 17 CFR 38.711 - Warning letters.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Warning letters. 38.711... MARKETS Disciplinary Procedures § 38.711 Warning letters. Where a rule violation is found to have occurred, no more than one warning letter may be issued per rolling 12-month period for the same violation....

  8. 17 CFR 38.711 - Warning letters.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Warning letters. 38.711... MARKETS Disciplinary Procedures § 38.711 Warning letters. Where a rule violation is found to have occurred, no more than one warning letter may be issued per rolling 12-month period for the same violation....

  9. 19 CFR 354.7 - Charging letter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Charging letter. 354.7 Section 354.7 Customs... VIOLATION OF AN ANTIDUMPING OR COUNTERVAILING DUTY ADMINISTRATIVE PROTECTIVE ORDER § 354.7 Charging letter. (a) Contents of Letter. The Deputy Under Secretary will initiate proceedings by issuing a...

  10. Written Communications Simulation: Write Me a Letter.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Vocational Education.

    This simulation is intended for use as a culminating activity after students have been exposed to personal and/or business letter writing, use of reference manuals, typing of letters, mailing procedures, typing of numbers, punctuation practice, and filing procedures. Stated objectives are to enable students to type a mailable letter; to inspect,…

  11. Letter Writing in the College Classroom.

    ERIC Educational Resources Information Center

    Fredericksen, Elaine

    2000-01-01

    Suggests that beginning writers can improve skills when they exchange letters with peers, teachers, and others. Offers a brief historical perspective on the use of letters as a pedagogical device. Outlines current applications of letter writing and exchanges in: English as a second language; technical and business writing; composition and…

  12. Gotcha, Grandpa! More Letters to Grandchildren.

    ERIC Educational Resources Information Center

    Smith, Carl B.

    Letters and notes between grandchildren and grandparents can bring mutual benefits. This book shows grandparents how to start writing, what to write about, how to make writing fun and easy, how to get replies, and how to write memorable letters. The book, a sequel to "With Love, Grandma" (1998), provides sample letters on numerous topics…

  13. What Do Letter Migration Errors Reveal About Letter Position Coding in Visual Word Recognition?

    ERIC Educational Resources Information Center

    Davis, Colin J.; Bowers, Jeffrey S.

    2004-01-01

    Dividing attention across multiple words occasionally results in misidentifications whereby letters apparently migrate between words. Previous studies have found that letter migrations preserve within-word letter position, which has been interpreted as support for position-specific letter coding. To investigate this issue, the authors used word…

  14. An Attempt to Simulate Letter-by-Letter Dyslexia in Normal Readers

    ERIC Educational Resources Information Center

    Fiset, Stephanie; Arguin, Martin; Fiset, Daniel

    2006-01-01

    We attempted to simulate the main features of letter-by-letter (LBL) dyslexia in normal readers through stimulus degradation (i.e. contrast reduction and removal of high spatial frequencies). The results showed the word length and the letter confusability effects characteristic of LBL dyslexia. However, the interaction of letter confusability and…

  15. Learning Letter Names and Sounds: Effects of Instruction, Letter Type, and Phonological Processing Skill

    ERIC Educational Resources Information Center

    Piasta, Shayne B.; Wagner, Richard K.

    2010-01-01

    Preschool-age children (N = 58) were randomly assigned to receive instruction in letter names and sounds, letter sounds only, or numbers (control). Multilevel modeling was used to examine letter name and sound learning as a function of instructional condition and characteristics of both letters and children. Specifically, learning was examined in…

  16. Visual acuity in an opportunistic raptor, the chimango caracara (Milvago chimango).

    PubMed

    Potier, Simon; Bonadonna, Francesco; Kelber, Almut; Duriez, Olivier

    2016-04-01

    Raptors are always considered to have an extraordinary resolving power of their eyes (high visual acuity). Nevertheless, raptors differ in their diet and foraging tactics, which could lead to large differences in visual acuity. The visual acuity of an opportunist bird of prey, the Chimango caracara (Mivalgo chimango) was estimated by operant conditioning. Three birds were trained to discriminate two stimuli, a positive grey uniform pattern and a negative grating pattern stimulus. The visual acuity range from 15.08 to 39.83 cycles/degrees. When compared to other birds, they have a higher visual acuity than non-raptorial birds, but they have the lowest visual acuity found in bird of prey so far. We discuss this result in the context of the ecology of the bird, with special focus on it is foraging tactic.

  17. 50 years of JETP Letters

    NASA Astrophysics Data System (ADS)

    Pastukhov, V. P.

    2015-04-01

    This paper briefly traces the 50-year history of the journal Pis'ma v Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki (JETP Letters), whose first issue was published on 1 April 1965. The journal is intended for a wide circle of physicists-readers as a fast publication channel for short communications on new results from research of the highest significance and highest priority in all areas of experimental and theoretical physics. Today, the journal celebrates numerous important contributions to the development of physics both in Russia and worldwide. Over a historically short period, JETP Letters developed into a highly authoritative and influential source for physicists engaged in a wide range of fields. Due to the wise and well-timed editorial policy, the journal continues to retain its leadership position, despite the difficulties the entire science periodical literature - and indeed the whole of science - is currently experiencing in Russia.

  18. Spatio-temporal properties of letter crowding

    PubMed Central

    Chung, Susana T. L.

    2016-01-01

    Crowding between adjacent letters has been investigated primarily as a spatial effect. The purpose of this study was to investigate the spatio-temporal properties of letter crowding. Specifically, we examined the systematic changes in the degradation effects in letter identification performance when adjacent letters were presented with a temporal asynchrony, as a function of letter separation and between the fovea and the periphery. We measured proportion-correct performance for identifying the middle target letter in strings of three lowercase letters at the fovea and 10° in the inferior visual field, for a range of center-to-center letter separations and a range of stimulus onset asynchronies (SOA) between the target and flanking letters (positive SOAs: target preceded flankers). As expected, the accuracy for identifying the target letters reduces with decreases in letter separation. This crowding effect shows a strong dependency on SOAs, such that crowding is maximal between 0 and ∼100 ms (depending on conditions) and diminishes for larger SOAs (positive or negative). Maximal crowding does not require the target and flanking letters to physically coexist for the entire presentation duration. Most importantly, crowding can be minimized even for closely spaced letters if there is a large temporal asynchrony between the target and flankers. The reliance of letter identification performance on SOAs and how it changes with letter separations imply that the crowding effect can be traded between space and time. Our findings are consistent with the notion that crowding should be considered as a spatio-temporal, and not simply a spatial, effect. PMID:27088895

  19. Spatio-temporal properties of letter crowding.

    PubMed

    Chung, Susana T L

    2016-01-01

    Crowding between adjacent letters has been investigated primarily as a spatial effect. The purpose of this study was to investigate the spatio-temporal properties of letter crowding. Specifically, we examined the systematic changes in the degradation effects in letter identification performance when adjacent letters were presented with a temporal asynchrony, as a function of letter separation and between the fovea and the periphery. We measured proportion-correct performance for identifying the middle target letter in strings of three lowercase letters at the fovea and 10° in the inferior visual field, for a range of center-to-center letter separations and a range of stimulus onset asynchronies (SOA) between the target and flanking letters (positive SOAs: target preceded flankers). As expected, the accuracy for identifying the target letters reduces with decreases in letter separation. This crowding effect shows a strong dependency on SOAs, such that crowding is maximal between 0 and ∼100 ms (depending on conditions) and diminishes for larger SOAs (positive or negative). Maximal crowding does not require the target and flanking letters to physically coexist for the entire presentation duration. Most importantly, crowding can be minimized even for closely spaced letters if there is a large temporal asynchrony between the target and flankers. The reliance of letter identification performance on SOAs and how it changes with letter separations imply that the crowding effect can be traded between space and time. Our findings are consistent with the notion that crowding should be considered as a spatio-temporal, and not simply a spatial, effect.

  20. Validation of the Total Visual Acuity Extraction Algorithm (TOVA) for Automated Extraction of Visual Acuity Data From Free Text, Unstructured Clinical Records

    PubMed Central

    Baughman, Douglas M.; Su, Grace L.; Tsui, Irena; Lee, Cecilia S.; Lee, Aaron Y.

    2017-01-01

    Purpose With increasing volumes of electronic health record data, algorithm-driven extraction may aid manual extraction. Visual acuity often is extracted manually in vision research. The total visual acuity extraction algorithm (TOVA) is presented and validated for automated extraction of visual acuity from free text, unstructured clinical notes. Methods Consecutive inpatient ophthalmology notes over an 8-year period from the University of Washington healthcare system in Seattle, WA were used for validation of TOVA. The total visual acuity extraction algorithm applied natural language processing to recognize Snellen visual acuity in free text notes and assign laterality. The best corrected measurement was determined for each eye and converted to logMAR. The algorithm was validated against manual extraction of a subset of notes. Results A total of 6266 clinical records were obtained giving 12,452 data points. In a subset of 644 validated notes, comparison of manually extracted data versus TOVA output showed 95% concordance. Interrater reliability testing gave κ statistics of 0.94 (95% confidence interval [CI], 0.89–0.99), 0.96 (95% CI, 0.94–0.98), 0.95 (95% CI, 0.92–0.98), and 0.94 (95% CI, 0.90–0.98) for acuity numerators, denominators, adjustments, and signs, respectively. Pearson correlation coefficient was 0.983. Linear regression showed an R2 of 0.966 (P < 0.0001). Conclusions The total visual acuity extraction algorithm is a novel tool for extraction of visual acuity from free text, unstructured clinical notes and provides an open source method of data extraction. Translational Relevance Automated visual acuity extraction through natural language processing can be a valuable tool for data extraction from free text ophthalmology notes. PMID:28299240

  1. Visual acuity in ray-finned fishes correlates with eye size and habitat.

    PubMed

    Caves, Eleanor M; Sutton, Tracey T; Johnsen, Sönke

    2017-02-09

    Visual acuity (the ability to resolve spatial detail) is highly variable across fishes. However, little is known about the evolutionary pressures underlying this variation. We reviewed published literature to create an acuity database for 159 species of ray-finned fishes (Actinopterygii). Within a subset of those species for which we had phylogenetic information and anatomically-measured acuity data (n=81), we examined relationships between acuity and both morphological (eye size and body size) and ecological (light level, water turbidity, habitat spatial complexity, and diet) variables. Acuity was significantly correlated with eye size (p<0.05); a weaker correlation with body size occurred via a correlation between eye and body size (p<0.001). Acuity decreased as light level decreased and turbidity increased; however, these decreases resulted from fishes in dark or murky environments having smaller eyes and bodies than those in bright or clear environments. We also found significantly lower acuity in horizon-dominated habitats than in featureless or complex habitats. Higher acuity in featureless habitats is likely due to species having absolutely larger eyes and bodies in that environment, though eye size relative to body size is not significantly different from that in complex environments. Controlling for relative eye size, we found that species in complex environments have even higher acuity than predicted. We found no relationship between visual acuity and diet. Our results show that eye size is a primary factor underlying variation in fish acuity. We additionally show that habitat type is an important ecological factor that correlates with acuity in certain species.

  2. Recovery of visual acuity following the repair of pseudophakic retinal detachment.

    PubMed Central

    Isernhagen, R D; Wilkinson, C P

    1988-01-01

    Postoperative visual acuities were evaluated in a series of 100 pseudophakic eyes in which rhegmatogenous retinal detachments involved the macula and in which reattachment surgery was successful. Preoperative visual acuity and duration of macular detachment were directly and indirectly related to visual outcome, respectively. Eyes in which extracapsular surgery had been followed by posterior chamber lens implantation had significantly better postoperative visual acuities than cases in which older iris-fixation IOLs were placed following intracapsular procedures. PMID:2979019

  3. Spatial visual acuity of the eagle Aquila audax: a behavioural, optical and anatomical investigation.

    PubMed

    Reymond, L

    1985-01-01

    Behavioural acuity of the wedge-tailed eagle was determined across a range of luminance. Maximum acuity is between 132 and 143 c/deg and with decreasing luminance acuity declines sharply. The maximum anatomical resolving power of the eagle's deep fovea was calculated as 140 c/deg. This calculation was based upon ophthalmoscopic measurement of posterior nodal distance and estimates of photoreceptor spacings made from fixed foveal tissue and corrected for shrinkage. Maximum behavioural acuity and anatomical resolving power correspond closely and approach the highest frequency (157 c/deg) transmitted by the minimum pupil diameter of the eye. These findings are discussed with reference to current theories of visual functioning.

  4. Letters

    NASA Astrophysics Data System (ADS)

    1999-01-01

    A Coordination Geometry Table by Francisco J. Arnáiz Re: article by D. Venkataraman, Y. Du, S. R. Wilson, K. A. Hirsch, P. Zhang, and J. S. Moore The authors reply Cut-Out Molecular Models by A. L. Silva, C. Fernandes, O. Wasterlain, S. Costa, and A. M. Mendes Re: article by R. J. Kashmar Kinetics Lesson for College Deans by Fred Hadley

  5. Letters

    NASA Astrophysics Data System (ADS)

    1999-11-01

    Survey of Binary Azeotropes by Paul C. Yates Re: article by R. J. Glinski, C. W. Smith, and J. B. Cooke Cheating Probabilities? Probably Not by David J. Miller Re: a criticism by C. Jonah and a note by G. T. Rizzuto and F. Walters trans-Cyclohexane-1,2-diamine by Richard S. Treptow Re: article by P. J. Walsh, D. K. Smith, and C. Castello Micropreparation of [RuH2PPh3)4] by Francisco J. Arnáiz Re: article by D. E. Linn, Jr. The author replies D. E. Linn's response follows

  6. Letters

    NASA Astrophysics Data System (ADS)

    1998-12-01

    Beer's Law: The Real Hazards by S. R. Logan Re: article by M. A. Muyskens and E. T. Sevy The author replies Photodimerization of Maleic Anhydride by Zhijun Zhang Re: article by D. Todd and M. Pickering (J. Chem. Educ. 1988, 65, 1100) Qual from a Different Viewpoint by Francisco J. Arnáiz Re: article by M. Laing (J. Chem. Educ. 1993, 70, 666)

  7. Letters

    NASA Astrophysics Data System (ADS)

    2000-02-01

    Inflection at the Triple Point by R. Thomas Myers Author's reply: Stephen J. Hawkes Correction Figure 1 of the article Using Overhead Projector to Simulate X-ray Diffraction Experiments by Veljko Dragojlovic (J. Chem. Educ. 1999, 76, 1240-1241) had the images for the red filter and the blue filter reversed. The correctly labeled images are shown below. These images are shown in color in the JCE Online PDF version of this article. Figure 2. Diffraction patterns obtained with (a) red filter, (b) blue filter, and (c) without a filter.

  8. Letters

    NASA Astrophysics Data System (ADS)

    1999-12-01

    Levels of Description in Chemistry by P. G. Nelson Re: articles by W. B. Jensen in June, July, and August of 1998. The author replies Inexpensive Variable Path-Length Cells for Discovery-Based Investigation of the Beer-Lambert Law by Jonathan Mitschele Re: article by S. A. Stewart and A. J. Sommer CD Spectroscope by Lanny Whitten Re: Classroom Activity (CD Light: An Introduction to Spectroscopy) Correction The Literature Cited section was unfortunately omitted from the October 1999 NSF Highlights column, "Organic Chemistry Course Development in a Forensic Science Program: Use of FT-NMR" by Ronald Callahan, Lawrence Kobilinsky and Robert Rothchild (J. Chem. Educ. 1999, 76, 1332-1333). The references are provided in the PDF version.

  9. Letters

    NASA Astrophysics Data System (ADS)

    1999-10-01

    Copper Content in Synthetic Copper Carbonate: A Statistical Comparison of Experimental and Expected Results by H. Gamsjäger and W. Preis Re: article by D. Sheeran The author replies The Amateur Mineral Chemist by Dana Martin Morong More on Double Replacement by George B. Kauffman Re: article by R. B. Martin

  10. The UK Neovascular AMD Database Report 3: inter-centre variation in visual acuity outcomes and establishing real-world measures of care.

    PubMed

    Liew, G; Lee, A Y; Zarranz-Ventura, J; Stratton, I; Bunce, C; Chakravarthy, U; Lee, C S; Keane, P A; Sim, D A; Akerele, T; McKibbin, M; Downey, L; Natha, S; Bailey, C; Khan, R; Antcliff, R; Armstrong, S; Varma, A; Kumar, V; Tsaloumas, M; Mandal, K; Egan, C; Johnston, R L; Tufail, A

    2016-11-01

    PurposeInternational variations in visual acuity (VA) outcomes of eyes treated for neovascular age-related macular degeneration (nAMD) are well-documented, but intra-country inter-centre regional variations are not known. These data are important for national quality outcome indicators. We aimed to determine intra-country and inter-centre regional variations in outcomes for treatment of nAMD.Patients and methodsProspective multicentre national database study of 13 UK centres that treated patients according to a set protocol (three loading doses, followed by Pro-Re-Nata retreatment). A total of 5811 treatment naive eyes of 5205 patients received a total of 36 206 ranibizumab injections over 12 months.ResultsMean starting VA between centres varied from 48.9 to 59.9 ETDRS letters. Mean inter-centre VA change from baseline to 12 months varied from +6.9 letters to -0.6 letters (mean of +2.5 letters). The proportion of eyes achieving VA of 70 letters or more varied between 21.9 and 48.7% at 12 months. Median number of injections (visits) at each centre varied from 5 to 8 (9 to 12), with an overall median of 6 (11). Age, starting VA, number of injections, and visits, but not gender were significantly associated with variation in these VA outcomes (P<0.01). Significant variation between centres persisted even after adjusting for these factors.ConclusionThere are modest differences in VA outcomes between centres in the UK. These differences are influenced, but not completely explained, by factors such as patient age, starting VA, number of injections, and visits. These data provide an indication of the VA outcomes that are achievable in real-world settings.

  11. Testing vision testing: quantifying the effect of movement on visual acuity measurement

    PubMed Central

    Tidbury, L P; O'Connor, A R

    2015-01-01

    Purpose Assessment of visual acuity (VA) has been shown to vary between tests, which may be attributable in part to test inaccuracies, such as a change in the distance between the chart and subject. Therefore, the study aim was to quantify changes in chart/patient separation during near and distance VA testing, and to analyse the relationship between VA and movement observed. Methods Volunteer orthoptists and subjects were filmed during near and distance VA testing, with the amount of movement determined from the recording. Controlling for movement using chin rests and chart stands, VA was retested. Actual changes in VA due to a change in subject or chart movement were compared with theoretical predictions. Results Fifty-one subjects (18–73 years) were assessed. Median (interquartile) movements of 0.06 m (0.07) towards and 0.11 m (0.08) away from the chart were measured (maximum 0.17 m towards and 0.24 m away). Significant differences in VA score were measured when movement was restricted, at near and distance (P<0.05). VA score change agreed with predicted values in 67% of the cases, however, reduced test distance during near vision testing resulted in a degradation of VA, opposite to the improvement expected. Conclusion There were significant variations in subject/chart separation during testing, which could have affected VA values. While this movement is associated with a change in VA, additional factors to movement appear to influence the score achieved during near testing. Procedures to minimise variation, by eliminating movement of test chart or subject, will improve VA test accuracy. PMID:25341437

  12. Sensitivity of The Dynamic Visual Acuity Test To Sensorimotor Change

    NASA Technical Reports Server (NTRS)

    Cohen, Helen; Bloomberg, Jacob; Elizalde, Elizabeth; Fregia, Melody

    1999-01-01

    Post-flight astronauts, acutely post-vestibular nerve section patients, and patients with severe chronic bilateral vestibular deficits have oscillopsia caused by reduced vestibulocular reflex gains and decreased postural stability. Therefore, as previous work has shown, a test of dynamic visual acuity (DVA), in which the subject must read numbers from a computer screen while standing still or walking in place provides a composite measure of sensorimotor integration. This measure may be useful for determining the level of recovery, post-flight, post-operatively, or after vestibular rehabilitation. To determine the sensitivity of DVA to change in impaired populations we have tested patients with acoustic neuromas before and during the first post-operative week after resection of the tumors, and with bilaterally labyrinthine deficient subjects before and after six weeks of balance rehabilitation therapy.

  13. Recovery of stereo acuity in adults with amblyopia

    PubMed Central

    Astle, Andrew T; McGraw, Paul V; Webb, Ben S

    2011-01-01

    Disruption of visual input to one eye during early development leads to marked functional impairments of vision, commonly referred to as amblyopia. A major consequence of amblyopia is the inability to encode binocular disparity information leading to impaired depth perception or stereo acuity. If amblyopia is treated early in life (before 4 years of age), then recovery of normal stereoscopic function is possible. Treatment is rarely undertaken later in life (adulthood) because declining levels of neural plasticity are thought to limit the effectiveness of standard treatments. Here, the authors show that a learning-based therapy, designed to exploit experience-dependent plastic mechanisms, can be used to recover stereoscopic visual function in adults with amblyopia. These cases challenge the long-held dogma that the critical period for visual development and the window for treating amblyopia are one and the same. PMID:22707543

  14. Collective enhancement of numerical acuity by meritocratic leadership in fish.

    PubMed

    Bisazza, Angelo; Butterworth, Brian; Piffer, Laura; Bahrami, Bahador; Miletto Petrazzini, Maria Elena; Agrillo, Christian

    2014-04-02

    It has been known for more than a century that interacting people can generally achieve more accurate decisions than single individuals. Here we show that interacting guppy fish (Poecilia reticulata) achieve a superior level of numerosity discrimination well beyond the average ability of the isolated individual fish. This enhancement of numerical acuity was observed in dyadic interactions when (Experiment 1) the dyad chose which larger shoal of guppies to join and when (Experiment 2) the dyad chose the higher or the lower numerosity among two decision options after having learned the task individually. Dyadic accuracy and that of the more competent member of each dyad matched closely, supporting the hypothesis that meritocratic leadership arises spontaneously between dyadically interacting fish, rather than the 'many wrongs' principle that has been used to explain group superiority in many species.

  15. Photovoltaic restoration of sight with high visual acuity.

    PubMed

    Lorach, Henri; Goetz, Georges; Smith, Richard; Lei, Xin; Mandel, Yossi; Kamins, Theodore; Mathieson, Keith; Huie, Philip; Harris, James; Sher, Alexander; Palanker, Daniel

    2015-05-01

    Patients with retinal degeneration lose sight due to the gradual demise of photoreceptors. Electrical stimulation of surviving retinal neurons provides an alternative route for the delivery of visual information. We demonstrate that subretinal implants with 70-μm-wide photovoltaic pixels provide highly localized stimulation of retinal neurons in rats. The electrical receptive fields recorded in retinal ganglion cells were similar in size to the natural visual receptive fields. Similarly to normal vision, the retinal response to prosthetic stimulation exhibited flicker fusion at high frequencies, adaptation to static images and nonlinear spatial summation. In rats with retinal degeneration, these photovoltaic arrays elicited retinal responses with a spatial resolution of 64 ± 11 μm, corresponding to half of the normal visual acuity in healthy rats. The ease of implantation of these wireless and modular arrays, combined with their high resolution, opens the door to the functional restoration of sight in patients blinded by retinal degeneration.

  16. Photovoltaic restoration of sight with high visual acuity

    PubMed Central

    Lorach, Henri; Goetz, Georges; Smith, Richard; Lei, Xin; Mandel, Yossi; Kamins, Theodore; Mathieson, Keith; Huie, Philip; Harris, James; Sher, Alexander; Palanker, Daniel

    2015-01-01

    Patients with retinal degeneration lose sight due to gradual demise of photoreceptors. Electrical stimulation of the surviving retinal neurons provides an alternative route for delivery of visual information. We demonstrate that subretinal arrays with 70 μm photovoltaic pixels provide highly localized stimulation, with electrical and visual receptive fields of comparable sizes in rat retinal ganglion cells. Similarly to normal vision, retinal response to prosthetic stimulation exhibits flicker fusion at high frequencies, adaptation to static images and non-linear spatial summation. In rats with retinal degeneration, these photovoltaic arrays provide spatial resolution of 64 ± 11 μm, corresponding to half of the normal visual acuity in pigmented rats. Ease of implantation of these wireless and modular arrays, combined with their high resolution opens the door to functional restoration of sight. PMID:25915832

  17. Predicting visual acuity from the structure of visual cortex

    PubMed Central

    Srinivasan, Shyam; Carlo, C. Nikoosh; Stevens, Charles F.

    2015-01-01

    Three decades ago, Rockel et al. proposed that neuronal surface densities (number of neurons under a square millimeter of surface) of primary visual cortices (V1s) in primates is 2.5 times higher than the neuronal density of V1s in nonprimates or many other cortical regions in primates and nonprimates. This claim has remained controversial and much debated. We replicated the study of Rockel et al. with attention to modern stereological precepts and show that indeed primate V1 is 2.5 times denser (number of neurons per square millimeter) than many other cortical regions and nonprimate V1s; we also show that V2 is 1.7 times as dense. As primate V1s are denser, they have more neurons and thus more pinwheels than similar-sized nonprimate V1s, which explains why primates have better visual acuity. PMID:26056277

  18. A comparison of vernier acuity for narrowband and broadband stimuli.

    PubMed

    Barrett, Brendan T; Whitaker, David

    2004-01-01

    This study investigates the influence of contrast and exposure duration on vernier acuity thresholds for abutting and separated narrowband stimuli, and asks whether these data can predict broadband vernier performance. Vernier thresholds were determined for sinusoidal grating stimuli at two spatial frequencies (1 and 8 c/deg) across a range of contrasts (0.05-0.8) and exposure durations (35-2100 ms). Performance was assessed for the abutting configuration, and when a gap equivalent to 0.5 to 1.5 times the spatial period of the grating was introduced between the upper and lower halves of the grating. Vernier thresholds were also determined for a square-wave stimulus as a function of contrast (0.06 to 0.78). Exposure duration was fixed at 2100 ms. In addition, thresholds were determined at the appropriate contrast levels for the fundamental frequency (1.8 c/deg) of the square-wave, and for a number of the harmonics (3F, 5F, 7F, 9F). Our results provide support for filter models of vernier acuity by showing that vernier performance for abutting and closely-separated broadband stimuli represents the envelope of vernier sensitivity of those spatial frequency mechanisms that are activated by the broadband stimulus. In the case of high frequency grating stimuli presented for long exposure durations, vernier performance can be invariant across much of the contrast range. Despite this, however, contrast independence is not exhibited for abutting broadband stimuli because, within the broadband stimuli, the contrast of the higher harmonic components never reaches a level to reveal this plateau.

  19. Amblyopia and visual acuity in children with Down's syndrome

    PubMed Central

    Tsiaras, W.; Pueschel, S.; Keller, C.; Curran, R.; Giesswein, S.

    1999-01-01

    BACKGROUND/AIMS—Amblyopia in people with Down's syndrome has not been well investigated. This study was designed to determine the prevalence and associated conditions of amblyopia in a group of home reared children with Down's syndrome.
METHODS—All children in the study group underwent an evaluation of visual acuity. In addition, previous ophthalmological records were reviewed, and a subgroup of children was examined. For the purposes of this study, amblyopia was defined quantitatively as a difference of two Snellen acuity lines between eyes or if unilateral central steady maintained (CSM) vision and a clear fixation preference was observed. A high refractive error was defined as a spherical equivalent more than 3 dioptres and astigmatism more than 1.75 dioptres. Anisometropia was defined as a difference of at least 1.5 dioptres of sphere and/or 1.0 dioptre of cylinder between eyes. 68 children with Down's syndrome between the ages of 5 and 19 years were enrolled in the final study group.
RESULTS—Amblyopia was observed in 15 (22%) of 68 patients. An additional 16 (24%) patients had bilateral vision less than 20/50. Strabismus, high refractive errors, and anisometropia were the conditions most commonly associated with decreased vision and amblyopia
CONCLUSION—This study suggests that the prevalence of amblyopia is higher than previously reported. Fully 46% of these children with Down's syndrome had evidence of substantial visual deficits. These patients may be at higher risk for visual impairment and should be carefully examined for ophthalmological problems.

 PMID:10502568

  20. Vernier Acuity and the Magnocellular System Revisited: Response to Skottun and Skoyles

    ERIC Educational Resources Information Center

    Keri, Szabolcs; Benedek, Gyorgy

    2010-01-01

    Skottun and Skoyles (2009) recently presented a comment on Vernier acuity and magnocellular dysfunctions in fragile X premutation carriers (Keri & Benedek, 2009). The authors concluded that our finding that the magnocellular deficit, as revealed by luminance-contrast sensitivity measurements, is associated with impaired Vernier acuity for…

  1. Visual Acuity of Radiologists: The Important but Forgotten Component of the Radiological Process.

    ERIC Educational Resources Information Center

    Good, Barbara C.

    This paper reports on a study of visual acuity among radiologists. Twenty-eight radiologists had their visual acuity tested by an optometrist. One week later, 70 medical school faculty radiologists were asked to respond to a printed questionnaire that elicited information about: (1) the date of the respondent's immediately previous examination;…

  2. Comparison of Dynamic Visual Acuity between Water Polo Players and Sedentary Students

    ERIC Educational Resources Information Center

    Quevedo-Junyent, Lluisa; Aznar-Casanova, Jose Antonio; Merindano-Encina, Dolores; Cardona, Genis; Sole-Forto, Joan

    2011-01-01

    In this study, we examined differences in dynamic visual acuity between elite and subelite water polo players and sedentary students. To measure dynamic visual acuity binocularly, we asked participants to indicate the orientation of a broken ring, similar to the Landolt C, which increased in size as it moved across a computer screen. Two different…

  3. Burn Patient Acuity Demographics, Scar Contractures and Rehabilitation Treatment Time Related to Patient Outcomes (ACT)

    DTIC Science & Technology

    2011-10-01

    Patient Acuity Demographics, Scar Contractures and Rehabilitation Treatment Time Related to Patient Outcomes (ACT) Mr. Reginald Richard American Burn...and Rehabilitation Treatment Time Related to Patient Outcomes, conveniently referred to as the ACT representing Acuity, Contractures and Time, is...wound leading to scar contracture begins almost immediately after the burning process stops. Rehabilitation treatment delivered prior to beginning

  4. 49 CFR 240.121 - Criteria for vision and hearing acuity data.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Criteria for vision and hearing acuity data. 240... ENGINEERS Component Elements of the Certification Process § 240.121 Criteria for vision and hearing acuity... paragraph (e) of this section, a person's vision and hearing shall meet or exceed the standards...

  5. 49 CFR 240.121 - Criteria for vision and hearing acuity data.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Criteria for vision and hearing acuity data. 240... ENGINEERS Component Elements of the Certification Process § 240.121 Criteria for vision and hearing acuity... paragraph (e) of this section, a person's vision and hearing shall meet or exceed the standards...

  6. 49 CFR 240.121 - Criteria for vision and hearing acuity data.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Criteria for vision and hearing acuity data. 240... ENGINEERS Component Elements of the Certification Process § 240.121 Criteria for vision and hearing acuity... paragraph (e) of this section, a person's vision and hearing shall meet or exceed the standards...

  7. 49 CFR 240.207 - Procedures for making the determination on vision and hearing acuity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Procedures for making the determination on vision and hearing acuity. 240.207 Section 240.207 Transportation Other Regulations Relating to... making the determination on vision and hearing acuity. (a) Each railroad, prior to initially...

  8. 49 CFR 240.121 - Criteria for vision and hearing acuity data.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Criteria for vision and hearing acuity data. 240... ENGINEERS Component Elements of the Certification Process § 240.121 Criteria for vision and hearing acuity... paragraph (e) of this section, a person's vision and hearing shall meet or exceed the standards...

  9. 49 CFR 240.207 - Procedures for making the determination on vision and hearing acuity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Procedures for making the determination on vision and hearing acuity. 240.207 Section 240.207 Transportation Other Regulations Relating to... making the determination on vision and hearing acuity. (a) Each railroad, prior to initially...

  10. 49 CFR 240.207 - Procedures for making the determination on vision and hearing acuity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Procedures for making the determination on vision and hearing acuity. 240.207 Section 240.207 Transportation Other Regulations Relating to... making the determination on vision and hearing acuity. (a) Each railroad, prior to initially...

  11. 49 CFR 240.121 - Criteria for vision and hearing acuity data.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Criteria for vision and hearing acuity data. 240... ENGINEERS Component Elements of the Certification Process § 240.121 Criteria for vision and hearing acuity... paragraph (e) of this section, a person's vision and hearing shall meet or exceed the standards...

  12. 49 CFR 240.207 - Procedures for making the determination on vision and hearing acuity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Procedures for making the determination on vision and hearing acuity. 240.207 Section 240.207 Transportation Other Regulations Relating to... making the determination on vision and hearing acuity. (a) Each railroad, prior to initially...

  13. 49 CFR 240.207 - Procedures for making the determination on vision and hearing acuity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Procedures for making the determination on vision and hearing acuity. 240.207 Section 240.207 Transportation Other Regulations Relating to... making the determination on vision and hearing acuity. (a) Each railroad, prior to initially...

  14. Acuity of the Approximate Number System and Preschoolers' Quantitative Development

    ERIC Educational Resources Information Center

    van Marle, Kristy; Chu, Felicia W.; Li, Yaoran; Geary, David C.

    2014-01-01

    The study assessed the relations among acuity of the inherent approximate number system (ANS), performance on measures of symbolic quantitative knowledge, and mathematics achievement for a sample of 138 (64 boys) preschoolers. The Weber fraction (a measure of ANS acuity) and associated task accuracy were significantly correlated with mathematics…

  15. Night vision in barn owls: visual acuity and contrast sensitivity under dark adaptation.

    PubMed

    Orlowski, Julius; Harmening, Wolf; Wagner, Hermann

    2012-12-06

    Barn owls are effective nocturnal predators. We tested their visual performance at low light levels and determined visual acuity and contrast sensitivity of three barn owls by their behavior at stimulus luminances ranging from photopic to fully scotopic levels (23.5 to 1.5 × 10⁻⁶). Contrast sensitivity and visual acuity decreased only slightly from photopic to scotopic conditions. Peak grating acuity was at mesopic (4 × 10⁻² cd/m²) conditions. Barn owls retained a quarter of their maximal acuity when luminance decreased by 5.5 log units. We argue that the visual system of barn owls is designed to yield as much visual acuity under low light conditions as possible, thereby sacrificing resolution at photopic conditions.

  16. Different aberrations raise contrast thresholds for single-letter identification in line with their effect on cross-correlation-based confusability.

    PubMed

    Young, Laura K; Love, Gordon D; Smithson, Hannah E

    2013-06-20

    We previously showed that different types of aberration defocus, coma, and secondary astigmatism affect reading performance via different mechanisms. In this paper, we show the contrary result that, for identification of isolated letters, the effects of rendering different types of aberration can be described by a single cross-correlation-based metric. Aberrations reduce the effective resolution of an optical system, quantified by the high-frequency fall-off of the modulation transfer function. They additionally cause spatial-frequency-dependent phase and contrast changes, which have a size-dependent effect on letter forms. We used contrast threshold as our performance measure, instead of distance acuity, to separate the effects of form alterations from those of resolution limits. This measure is additionally appropriate in comparing single-letter-based performance to reading at a fixed distance. The relationship between a cross-correlation-based measure of letter confusability and performance was the same for all three types of aberration. For reading, we had found a different relationship for coma than for defocus and secondary astigmatism. We conclude that even when two tasks--letter identification and reading--use the same component stimulus set, the combination of multiple letters in a reading task produces functional differences between the effects of these aberrations that are not present for isolated letters.

  17. A New Font, Specifically Designed for Peripheral Vision, Improves Peripheral Letter and Word Recognition, but Not Eye-Mediated Reading Performance

    PubMed Central

    Bernard, Jean-Baptiste; Aguilar, Carlos; Castet, Eric

    2016-01-01

    Reading speed is dramatically reduced when readers cannot use their central vision. This is because low visual acuity and crowding negatively impact letter recognition in the periphery. In this study, we designed a new font (referred to as the Eido font) in order to reduce inter-letter similarity and consequently to increase peripheral letter recognition performance. We tested this font by running five experiments that compared the Eido font with the standard Courier font. Letter spacing and x-height were identical for the two monospaced fonts. Six normally-sighted subjects used exclusively their peripheral vision to run two aloud reading tasks (with eye movements), a letter recognition task (without eye movements), a word recognition task (without eye movements) and a lexical decision task. Results show that reading speed was not significantly different between the Eido and the Courier font when subjects had to read single sentences with a round simulated gaze-contingent central scotoma (10° diameter). In contrast, Eido significantly decreased perceptual errors in peripheral crowded letter recognition (-30% errors on average for letters briefly presented at 6° eccentricity) and in peripheral word recognition (-32% errors on average for words briefly presented at 6° eccentricity). PMID:27074013

  18. The Eye Phone Study: reliability and accuracy of assessing Snellen visual acuity using smartphone technology

    PubMed Central

    Perera, C; Chakrabarti, R; Islam, F M A; Crowston, J

    2015-01-01

    Purpose Smartphone-based Snellen visual acuity charts has become popularized; however, their accuracy has not been established. This study aimed to evaluate the equivalence of a smartphone-based visual acuity chart with a standard 6-m Snellen visual acuity (6SVA) chart. Methods First, a review of available Snellen chart applications on iPhone was performed to determine the most accurate application based on optotype size. Subsequently, a prospective comparative study was performed by measuring conventional 6SVA and then iPhone visual acuity using the ‘Snellen' application on an Apple iPhone 4. Results Eleven applications were identified, with accuracy of optotype size ranging from 4.4–39.9%. Eighty-eight patients from general medical and surgical wards in a tertiary hospital took part in the second part of the study. The mean difference in logMAR visual acuity between the two charts was 0.02 logMAR (95% limit of agreement −0.332, 0.372 logMAR). The largest mean difference in logMAR acuity was noted in the subgroup of patients with 6SVA worse than 6/18 (n=5), who had a mean difference of two Snellen visual acuity lines between the charts (0.276 logMAR). Conclusion We did not identify a Snellen visual acuity app at the time of study, which could predict a patients standard Snellen visual acuity within one line. There was considerable variability in the optotype accuracy of apps. Further validation is required for assessment of acuity in patients with severe vision impairment. PMID:25931170

  19. Influence of Motion Smear on Visual Acuity in Simulated Infantile Nystagmus

    PubMed Central

    Chung, Susana T. L.; LaFrance, Martin W.; Bedell, Harold E.

    2011-01-01

    Purpose In persons with infantile nystagmus (IN), visual acuity correlates with the duration of the foveation period of the nystagmus waveform, i.e., when the retinal image is on or near the fovea and moves with low velocity. In this study, we asked how acuity is affected by the non-foveating phases of the nystagmus waveform, when the velocity of retinal image motion is substantially higher. Methods Visual acuity was measured in three normal observers for high-contrast, 4-orientation Ts, presented during image motion that simulated either the whole jerk-IN waveform (whole-waveform) or only the foveation periods of the IN waveform (foveation-only). Simulated foveation durations ranged from 20 to 120 ms. For both motion waveforms, we displayed the acuity target for different number of cycles to examine if acuity benefits from multiple presentations of the stimulus. Results As expected, visual acuity improves with longer simulated foveation durations in both the whole-waveform and foveation-only conditions. Acuity is consistently better (by approximately 0.1 logMAR) in the foveation-only than the whole-waveform condition, indicating that the high-velocity image motion during the simulated IN waveform has a detrimental effect. This difference in acuity between the two waveform conditions increases with the number of cycles, apparently because summation occurs across cycles in the foveation-only condition but not in the whole-waveform condition. Conclusions In normal observers, visual acuity in the presence of a simulated nystagmus waveform is limited not only by the duration of the foveation periods, but also by the non-foveating phases of the waveform. However, because persons with IN report little or no motion smear in association with their nystagmus, it remains unclear whether the rapid retinal image motion during the non-foveating phases of the nystagmus waveform generates a similar degradation of visual acuity in IN. PMID:21200353

  20. Letter to the Editor on Robert Yaes's Letter

    NASA Technical Reports Server (NTRS)

    Krisher, T. P.

    1993-01-01

    In his letter on page 13 of the March 1993 issue, Robert Yaes raised the question of whether the existence of the cosmic microwave background (CMB), now observed so precisely with COBE, is compatible with the principle of relativity: The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or other of two systems of coordinates in uniform translatory motion. Although I do not claim to provide an xpertresponse to this question, as desired by Yaes, it is my understanding that the principle of relativity is not necessarily violated by the mere existence of a universal reference frame. The laws of physics can still be invariant under some transformation of coordinates. This transformation is not specified by the principle of relativity itself, although we have discovered so far that Nature respects Lorentz invariance (principle of the constancy of the velocity of light).

  1. 1999 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    These letters, most of which are addressed to Administrator Carol Browner, are regarding a children's longitudinal cohort study, acute dietary exposure, cancer risk assessment, and residential exposure assessments.

  2. Effect of Orthographic Processes on Letter Identity and Letter-Position Encoding in Dyslexic Children

    PubMed Central

    Reilhac, Caroline; Jucla, Mélanie; Iannuzzi, Stéphanie; Valdois, Sylviane; Démonet, Jean-François

    2012-01-01

    The ability to identify letters and encode their position is a crucial step of the word recognition process. However and despite their word identification problem, the ability of dyslexic children to encode letter identity and letter-position within strings was not systematically investigated. This study aimed at filling this gap and further explored how letter identity and letter-position encoding is modulated by letter context in developmental dyslexia. For this purpose, a letter-string comparison task was administered to French dyslexic children and two chronological age (CA) and reading age (RA)-matched control groups. Children had to judge whether two successively and briefly presented four-letter strings were identical or different. Letter-position and letter identity were manipulated through the transposition (e.g., RTGM vs. RMGT) or substitution of two letters (e.g., TSHF vs. TGHD). Non-words, pseudo-words, and words were used as stimuli to investigate sub-lexical and lexical effects on letter encoding. Dyslexic children showed both substitution and transposition detection problems relative to CA-controls. A substitution advantage over transpositions was only found for words in dyslexic children whereas it extended to pseudo-words in RA-controls and to all type of items in CA-controls. Letters were better identified in the dyslexic group when belonging to orthographically familiar strings. Letter-position encoding was very impaired in dyslexic children who did not show any word context effect in contrast to CA-controls. Overall, the current findings point to a strong letter identity and letter-position encoding disorder in developmental dyslexia. PMID:22661961

  3. Test facilities for SCORE-D

    NASA Astrophysics Data System (ADS)

    Greuel, Dirk; Deeken, Jan; Suslov, Dmitry; Schäfer, Klaus; Schlechtriem, Stefan

    2013-06-01

    The LOX/LH2 Staged Combustion Rocket Engine Demonstrator (SCORE-D) is part of ESA's Future Launcher Preparatory Program (FLPP). SCORE-D serves as a technology demonstrator in perspective of the development of the High Thrust Engine (HTE), which is designated as a candidate for the main stage engine of the Next Generation Launcher (NGL). To develop and test the SCORE-D engine, ESA investigates configurations of the test benches P3.2 and P5 at DLR test site in Lampoldshausen. For the SCORE-D Hot Combustion Devices (HCD) development, i.e. Pre-burner (PB) and thrust chamber assembly (TCA), the P3.2 test facility has to be modified for further usage. Recently, the first steps in this endeavor have been made with the evaluation of the necessary modifications to the facility. To accommodate the SCORE-D engine, it is foreseen to modify the P5 test facility in the coming years. In the last year, DLR has started the design phase for these modifications. In preparatory test programs at the P8 test facility, Astrium has conducted sub-scale hot combustion devices tests. While Astrium designed and manufactured the sub-scale assembly of the pre-burner and the main combustion chamber (MCC) for SCORE-D, DLR operated the P8 test facility.

  4. Assessing victim empathy in sexual offenders using the victim letter task.

    PubMed

    Webster, Stephen D

    2002-10-01

    In attempting to enhance victim empathy, it is common to have sexual offenders write an apology letter to their victim. This task is thought to reveal the level of empathy that the sexual offender has for his victim. However, until now there has been no reliable method for judging the quality of empathy revealed in the victim letter. This paper reports the development and evaluation of 2 templates to score letters written to child victims and adult victims, respectively. An acceptable level of interrater reliability was obtained for the templates. Deficits revealed by the templates did not correlate with scores on a generic empathy measure but did correlate with scales measuring minimization and denial. The measures were also sensitive to change following empathy training.

  5. Malingering or simulation in ophthalmology-visual acuity

    PubMed Central

    Incesu, Ali Ihsan; Sobacı, Güngör

    2011-01-01

    Simulation can be defined as malingering, or sometimes functional visual loss (FVL). It manifests as either simulating an ophthalmic disease (positive simulation), or denial of ophthalmic disease (negative simulation). Conscious behavior and compensation or indemnity claims are prominent features of simulation. Since some authors suggest that this is a manifestation of underlying psychopathology, even conversion is included in this context. In today's world, every ophthalmologist can face with simulation of ophthalmic disease or disorder. In case of simulation suspect, the physician's responsibility is to prove the simulation considering the disease/disorder first, and simulation as an exclusion. In simulation examinations, the physician should be firm and smart to select appropriate test(s) to convince not only the subject, but also the judge in case of indemnity or compensation trials. Almost all ophthalmic sensory and motor functions including visual acuity, visual field, color vision and night vision can be the subject of simulation. Examiner must be skillful in selecting the most appropriate test. Apart from those in the literature, we included all kinds of simulation in ophthalmology. In addition, simulation examination techniques, such as, use of OCT (optical coherence tomography), frequency doubling perimetry (FDP), and modified polarization tests were also included. In this review, we made a thorough literature search, and added our experiences to give the readers up-to-date information on malingering or simulation in ophthalmology. PMID:22553721

  6. Objective evaluation of the visual acuity in human eyes

    NASA Astrophysics Data System (ADS)

    Rosales, M. A.; López-Olazagasti, E.; Ramírez-Zavaleta, G.; Varillas, G.; Tepichín, E.

    2009-08-01

    Traditionally, the quality of the human vision is evaluated by a subjective test in which the examiner asks the patient to read a series of characters of different sizes, located at a certain distance of the patient. Typically, we need to ensure a subtended angle of vision of 5 minutes, which implies an object of 8.8 mm high located at 6 meters (normal or 20/20 visual acuity). These characters constitute what is known as the Snellen chart, universally used to evaluate the spatial resolution of the human eyes. The mentioned process of identification of characters is carried out by means of the eye - brain system, giving an evaluation of the subjective visual performance. In this work we consider the eye as an isolated image-forming system, and show that it is possible to isolate the function of the eye from that of the brain in this process. By knowing the impulse response of the eye´s system we can obtain, in advance, the image of the Snellen chart simultaneously. From this information, we obtain the objective performance of the eye as the optical system under test. This type of results might help to detect anomalous situations of the human vision, like the so called "cerebral myopia".

  7. Insects groom their antennae to enhance olfactory acuity

    PubMed Central

    Böröczky, Katalin; Wada-Katsumata, Ayako; Batchelor, Dale; Zhukovskaya, Marianna; Schal, Coby

    2013-01-01

    Grooming, a common behavior in animals, serves the important function of removing foreign materials from body surfaces. When antennal grooming was prevented in the American cockroach, Periplaneta americana, field emission gun scanning electron microscopy images revealed that an unstructured substance accumulated on nongroomed antennae, covering sensillar pores, but not on groomed antennae of the same individuals. Gas chromatography analysis of antennal extracts showed that over a 24-h period nongroomed antennae accumulated three to four times more cuticular hydrocarbons than groomed antennae. Moreover, nongroomed antennae accumulated significantly more environmental contaminants from surfaces (stearic acid) and from air (geranyl acetate) than groomed antennae. We hypothesized that the accumulation of excess native cuticular hydrocarbons on the antennae would impair olfactory reception. Electroantennogram experiments and single-sensillum recordings supported this hypothesis: antennae that were prevented from being groomed were significantly less responsive than groomed antennae to the sex pheromone component periplanone-B, as well as to the general odorants geranyl acetate and hexanol. We therefore conclude that antennal grooming removes excess native cuticular lipids and foreign chemicals that physically and/or chemically interfere with olfaction, and thus maintains the olfactory acuity of the antennae. Similar experimental manipulations of the German cockroach (Blattella germanica), carpenter ant (Camponotus pennsylvanicus), and the housefly (Musca domestica), which use different modes of antennal grooming, support the hypothesis that antennal grooming serves a similar function in a wide range of insect taxa. PMID:23382193

  8. Face context advantage explained by vernier and separation discrimination acuity.

    PubMed

    Vesker, Michael; Wilson, Hugh R

    2012-01-01

    Seeing facial features in the context of a full face is known to provide an advantage for perception. Using an interocular separation perception task we confirmed that seeing eyes within the context of a face improves discrimination in synthetic faces. We also show that this improvement of the face context can be explained using the presence of individual components of the face such as the nose mouth, or head-outline. We demonstrate that improvements due to the presence of the nose, and head-outline can be explained in terms of two-point separation measurements, obeying Weber's law as established in the literature. We also demonstrate that performance improvements due to the presence of the mouth can be explained in terms of Vernier acuity judgments between eye positions and the corners of the mouth. Overall, our study shows that the improvements in perception of facial features due to the face context effect can be traced to well understood basic visual measurements that may play a very general role in perceptual measurements of distance. Deficiencies in these measurements may also play a role in prosopagnosia. Additionally, we show interference of the eyebrows with the face-inversion effect for interocular discrimination.

  9. Cognitive aging and hearing acuity: modeling spoken language comprehension

    PubMed Central

    Wingfield, Arthur; Amichetti, Nicole M.; Lash, Amanda

    2015-01-01

    The comprehension of spoken language has been characterized by a number of “local” theories that have focused on specific aspects of the task: models of word recognition, models of selective attention, accounts of thematic role assignment at the sentence level, and so forth. The ease of language understanding (ELU) model (Rönnberg et al., 2013) stands as one of the few attempts to offer a fully encompassing framework for language understanding. In this paper we discuss interactions between perceptual, linguistic, and cognitive factors in spoken language understanding. Central to our presentation is an examination of aspects of the ELU model that apply especially to spoken language comprehension in adult aging, where speed of processing, working memory capacity, and hearing acuity are often compromised. We discuss, in relation to the ELU model, conceptions of working memory and its capacity limitations, the use of linguistic context to aid in speech recognition and the importance of inhibitory control, and language comprehension at the sentence level. Throughout this paper we offer a constructive look at the ELU model; where it is strong and where there are gaps to be filled. PMID:26124724

  10. easyCBM[R] Slope Reliability: Letter Names, Word Reading Fluency, and Passage Reading Fluency. Technical Report #1111

    ERIC Educational Resources Information Center

    Patarapichayatham, Chalie; Anderson, Daniel; Irvin, P. Shawn; Kamata, Akhito; Alonzo, Julie; Tindal, Gerald

    2011-01-01

    Within a response to intervention (RTI) framework, students are administered multiple tests of equivalent difficulty. Changes in students' scores over time are then attributed to changes in learning. In the current study, we evaluated the reliability of score changes (i.e., slope) for the easyCBM[R] letter names, word reading fluency, and passage…

  11. Letter Names and Phonological Awareness Help Children to Learn Letter-Sound Relations

    ERIC Educational Resources Information Center

    Cardoso-Martins, Claudia; Mesquita, Tereza Cristina Lara; Ehri, Linnea

    2011-01-01

    Two experimental training studies with Portuguese-speaking preschoolers in Brazil were conducted to investigate whether children benefit from letter name knowledge and phonological awareness in learning letter-sound relations. In Experiment 1, two groups of children were compared. The experimental group was taught the names of letters whose sounds…

  12. Disentangling the Developmental Trajectories of Letter Position and Letter Identity Coding Using Masked Priming

    ERIC Educational Resources Information Center

    Kezilas, Yvette; McKague, Meredith; Kohnen, Saskia; Badcock, Nicholas A.; Castles, Anne

    2017-01-01

    Masked transposed-letter (TL) priming effects have been used to index letter position processing over the course of reading development. Whereas some studies have reported an increase in TL priming over development, others have reported a decrease. These findings have led to the development of 2 somewhat contradictory accounts of letter position…

  13. Letter Names: Effect on Letter Saying, Spelling, and Word Recognition in Hebrew.

    ERIC Educational Resources Information Center

    Levin, Iris; Patel, Sigal; Margalit, Tamar; Barad, Noa

    2002-01-01

    Examined whether letter names, which bridge the gap between oral and written language among English speaking children, have a similar function in Hebrew. In findings from studies of Israeli kindergartners and first graders, children were found to rely on letter names in performing a number of letter saying, spelling, and word recognition tasks.…

  14. Osler and the Infected Letter

    PubMed Central

    2005-01-01

    The spread of infectious agents through the mail has concerned public health officials for 5 centuries. The dissemination of anthrax spores in the US mail in 2001 was a recent example. In 1901, two medical journals reported outbreaks of smallpox presumably introduced by letters contaminated with variola viruses. The stability and infectivity of the smallpox virus are reviewed from both a historical (anecdotal) perspective and modern virologic studies. Bubonic plague was the contagious disease that led to quarantines as early as the 14th century in port cities in southern Europe. Later, smallpox, cholera, typhus, and yellow fever were recognized as also warranting quarantine measures. Initially, attempts were made to decontaminate all goods imported from pestilential areas, particularly mail. Disinfection of mail was largely abandoned in the early 20th century with newer knowledge about the spread and stability of these 5 infectious agents. PMID:15890120

  15. Visual acuity and quality of life in dry eye disease: Proceedings of the OCEAN group meeting.

    PubMed

    Benítez-Del-Castillo, José; Labetoulle, Marc; Baudouin, Christophe; Rolando, Maurizio; Akova, Yonca A; Aragona, Pasquale; Geerling, Gerd; Merayo-Lloves, Jesús; Messmer, Elisabeth M; Boboridis, Kostas

    2017-04-01

    Dry eye disease (DED) results in tear film instability and hyperosmolarity, inflammation of the ocular surface and, ultimately, visual disturbance that can significantly impact a patient's quality of life. The effects on visual acuity result in difficulties with driving, reading and computer use and negatively impact psychological health. These effects also extend to the workplace, with a loss of productivity and quality of work causing substantial economic losses. The effects of DED and the impact on vision experienced by patients may not be given sufficient importance by ophthalmologists. Functional visual acuity (FVA) is a measure of visual acuity after sustained eye opening without blinking for at least 10 s and mimics the sustained visual acuity of daily life. Measuring dynamic FVA allows the detection of impaired visual function in patients with DED who may display normal conventional visual acuity. There are currently several tests and methods that can be used to measure dynamic visual function: the SSC-350 FVA measurement system, assessment of best-corrected visual acuity decay using the interblink visual acuity decay test, serial measurements of ocular and corneal higher order aberrations, and measurement of dynamic vision quality using the Optical Quality Analysis System. Although the equipment for these methods may be too large or unaffordable for use in clinical practice, FVA testing is an important assessment for DED.

  16. ANS acuity and mathematics ability in preschoolers from low-income homes: contributions of inhibitory control.

    PubMed

    Fuhs, Mary Wagner; McNeil, Nicole M

    2013-01-01

    Recent findings by Libertus, Feigenson, and Halberda (2011) suggest that there is an association between the acuity of young children's approximate number system (ANS) and their mathematics ability before exposure to instruction in formal schooling. The present study examined the generalizability and validity of these findings in a sample of preschoolers from low-income homes. Children attending Head Start (N = 103) completed measures to assess ANS acuity, mathematics ability, receptive vocabulary, and inhibitory control. Results showed only a weak association between ANS acuity and mathematics ability that was reduced to non-significance when controlling for a direct measure of receptive vocabulary. Results also revealed that inhibitory control plays an important role in the relation between ANS acuity and mathematics ability. Specifically, ANS acuity accounted for significant variance in mathematics ability over and above receptive vocabulary, but only for ANS acuity trials in which surface area conflicted with numerosity. Moreover, this association became non-significant when controlling for inhibitory control. These results suggest that early mathematical experiences prior to formal schooling may influence the strength of the association between ANS acuity and mathematics ability and that inhibitory control may drive that association in young children.

  17. The Potential Importance of Detection of Neovascular Age-Related Macular Degeneration When Visual Acuity Is Relatively Good.

    PubMed

    Ho, Allen C; Albini, Thomas A; Brown, David M; Boyer, David S; Regillo, Carl D; Heier, Jeffrey S

    2017-03-01

    The advent of anti-vascular endothelial growth factor treatment has changed the prognosis for patients with neovascular age-related macular degeneration (nvAMD). The ability to stabilize or improve vision with these treatments is a major step in enabling patients to continue to function at the highest possible level. Many studies have demonstrated that the better the visual acuity (VA) is at the time of treatment initiation, the higher the likelihood that VA will be better during at least the following 2 years; as such, detection of nvAMD when VA is relatively good is important. Data on the VA of patients with intermediate AMD and VA at the time of nvAMD diagnosis suggest that patients are typically losing an average of 3 to 5 lines of vision and possibly more between the time that intermediate AMD progresses to nvAMD and the diagnosis of nvAMD is made. The average patient may have nvAMD for 6 to 12 months before diagnosis and treatment initiation. Current efforts in management of nvAMD are primarily aimed at optimizing anti-vascular endothelial growth factor treatments that have the potential to improve VA outcomes by a magnitude of letters. Additional tools or other efforts to identify patients with nvAMD before substantial vision loss has occurred may reduce the amount of visual loss sustained with anti-vascular endothelial growth factor therapy, and have the potential to improve VA outcomes substantially.

  18. Visual Acuity, Retinal Sensitivity, and Macular Thickness Changes in Diabetic Patients without Diabetic Retinopathy after Cataract Surgery.

    PubMed

    Stunf Pukl, Spela; Vidović Valentinčič, Nataša; Urbančič, Mojca; Irman Grčar, Irena; Grčar, Rok; Pfeifer, Vladimir; Globočnik Petrovič, Mojca

    2017-01-01

    Aim. Functional and morphological macular study after cataract surgery in a group of diabetics without diabetic retinopathy compared to nondiabetics to evaluate the effect of surgical oxidative stress on diabetic retina. Methods. Prospective, comparative study. Preoperative eye exam, best corrected visual acuity (BCVA) measured by ETDRS letters, and optical coherence tomography (OCT) were followed by standard cataract surgery. The follow-up visits at 1, 3, and 6 months postoperatively included BCVA, OCT, and microperimetry, to analyze changes within and between the groups. Results. The BCVA improved significantly in diabetics and controls: 64.2 to 81.0 and 61.9 to 82.1 ETDRS at 6 months, respectively. The central macula at OCT significantly thickened in both groups, while the central 5 fields, corresponding to the microperimetry area, subclinically thickened from 284.20 to 291.18 μm at 6 months only in diabetics (p = 0.026). A matching slight decrease in the microperimetry sensitivity from 1 to 6 months was found also only in diabetics, with mean average difference -0.75 dB (p = 0.04). Conclusion. Underlying diabetes does not influence the surgical outcome in diabetics without diabetic retinopathy. However, slight thickening of wider macula and corresponding decrease in retinal sensitivity observed in diabetics 6 months postoperatively might influence visual function on long term.

  19. Visual Acuity, Retinal Sensitivity, and Macular Thickness Changes in Diabetic Patients without Diabetic Retinopathy after Cataract Surgery

    PubMed Central

    Irman Grčar, Irena; Grčar, Rok; Pfeifer, Vladimir

    2017-01-01

    Aim. Functional and morphological macular study after cataract surgery in a group of diabetics without diabetic retinopathy compared to nondiabetics to evaluate the effect of surgical oxidative stress on diabetic retina. Methods. Prospective, comparative study. Preoperative eye exam, best corrected visual acuity (BCVA) measured by ETDRS letters, and optical coherence tomography (OCT) were followed by standard cataract surgery. The follow-up visits at 1, 3, and 6 months postoperatively included BCVA, OCT, and microperimetry, to analyze changes within and between the groups. Results. The BCVA improved significantly in diabetics and controls: 64.2 to 81.0 and 61.9 to 82.1 ETDRS at 6 months, respectively. The central macula at OCT significantly thickened in both groups, while the central 5 fields, corresponding to the microperimetry area, subclinically thickened from 284.20 to 291.18 μm at 6 months only in diabetics (p = 0.026). A matching slight decrease in the microperimetry sensitivity from 1 to 6 months was found also only in diabetics, with mean average difference −0.75 dB (p = 0.04). Conclusion. Underlying diabetes does not influence the surgical outcome in diabetics without diabetic retinopathy. However, slight thickening of wider macula and corresponding decrease in retinal sensitivity observed in diabetics 6 months postoperatively might influence visual function on long term. PMID:28243608

  20. Letters in Time and Retinotopic Space

    ERIC Educational Resources Information Center

    Adelman, James S.

    2011-01-01

    Various phenomena in tachistoscopic word identification and priming (WRODS and LTRS are confused with and prime WORDS and LETTERS) suggest that position-specific channels are not used in the processing of letters in words. Previous approaches to this issue have sought alternative matching rules because they have assumed that these phenomena reveal…

  1. Letter to, and Paintings by, George Catlin

    ERIC Educational Resources Information Center

    Rosenbaum, David; Potter, Lee Ann; Eder, Elizabeth K.

    2008-01-01

    Letters received and sent by Secretary of War Lewis Cass in the 1830s reveal much about relations between the U.S. government and Native Americans. In the immediate aftermath of the Indian Removal Act, signed into law on May 28, 1830, by President Andrew Jackson, some letters came from interpreters and school teachers seeking payment for their…

  2. 48 CFR 18.112 - Letter contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Letter contracts. 18.112 Section 18.112 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities 18.112 Letter...

  3. 48 CFR 18.112 - Letter contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Letter contracts. 18.112 Section 18.112 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities 18.112 Letter...

  4. 48 CFR 18.112 - Letter contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Letter contracts. 18.112 Section 18.112 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities 18.112 Letter...

  5. 48 CFR 18.112 - Letter contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Letter contracts. 18.112 Section 18.112 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities 18.112 Letter...

  6. 48 CFR 316.603 - Letter contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Letter contracts. 316.603 Section 316.603 Federal Acquisition Regulations System HEALTH AND HUMAN SERVICES CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts 316.603...

  7. An Open Letter to Tomorrow's Secondary Teachers

    ERIC Educational Resources Information Center

    Worthy, Jeff

    2016-01-01

    The article takes the form of a letter written to pre-service or beginning teachers at the secondary level in the public school system. The letter acknowledges the attributes they bring to the profession (enthusiasm, optimism, creativity, and open-mindedness) and calls on them to make the most of and work to sustain these traits as they begin…

  8. An Open Letter to Premier Wen Jiabao

    ERIC Educational Resources Information Center

    Chinese Education and Society, 2008

    2008-01-01

    This article is an open letter of a group of early childhood education (ECE) practitioners to Premier Wen Jiabao. This open letter was written with one goal in mind: to ask Premier Wen's government to take measures to protect young children and support early childhood education. These practitioners have become worried about the many accidents that…

  9. 48 CFR 16.603 - Letter contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Letter contracts. 16.603 Section 16.603 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Time-and-Materials, Labor-Hour, and Letter Contracts...

  10. 48 CFR 18.112 - Letter contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Letter contracts. 18.112 Section 18.112 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities 18.112 Letter...

  11. 49 CFR 107.309 - Warning letters.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Warning letters. 107.309 Section 107.309 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Associate Administrator may issue a warning letter to any person whom the Associate Administrator...

  12. 49 CFR 107.309 - Warning letters.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Warning letters. 107.309 Section 107.309 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Associate Administrator may issue a warning letter to any person whom the Associate Administrator...

  13. 49 CFR 107.309 - Warning letters.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Warning letters. 107.309 Section 107.309 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Associate Administrator may issue a warning letter to any person whom the Associate Administrator...

  14. Essay: the origin of physical review letters.

    PubMed

    Trigg, George L

    2008-11-21

    When Sam Goudsmit, then Editor of Physical Review, decided to publish the Letters separately, he asked me to become Assistant Editor of the new journal. I wound up staying at PRL for a quarter of a century. I describe some of the new techniques we developed to speed up review and production so that Letters could be quickly published.

  15. Cognitive Determinants of Early Letter Knowledge

    ERIC Educational Resources Information Center

    Helal, Suha; Weil-Barais, Annick

    2015-01-01

    The present study investigated the general cognitive determinants of alphabetic letter knowledge. It involved 60 French kindergarten children (mean age: five years six months). Two test batteries were used: the CMS to evaluate general cognitive abilities (memory, attention, and learning), and the LKT to assess letter knowledge and its various…

  16. Linguistic Prescriptivism in Letters to the Editor

    ERIC Educational Resources Information Center

    Lukac, Morana

    2016-01-01

    The public's concern with the fate of the standard language has been well documented in the history of the complaint tradition. The print media have for centuries featured letters to the editor on questions of language use. This study examines a corpus of 258 language-related letters to the editor published in the English-speaking print media. By…

  17. Genre Analysis of Business Letters of Negotiation.

    ERIC Educational Resources Information Center

    dos Santos, V. B. M. Pinto

    2002-01-01

    Reports findings of a survey on genre analysis of 117 commercial letters in English exchanged by fax between a Brazilian company and two European companies. The letters were analyzed in terms of shared communicative purposes and rhetorical features that together contribute to the building-up of the resulting generic structure named "Business…

  18. The Case of the Purloined Letter.

    ERIC Educational Resources Information Center

    Zirkel, Perry A.

    2003-01-01

    Analyzes Arkansas case wherein the Eighth Circuit held 6-5 that letter written by seventh-grade student threatening violence against his former girl friend was not protected by the First Amendment even though a friend took the letter from student's home without his knowledge and gave it to the girl. Upheld board's decision to expel student.…

  19. A Stimulus Sampling Theory of Letter Identity and Order

    ERIC Educational Resources Information Center

    Norris, Dennis; Kinoshita, Sachiko; van Casteren, Maarten

    2010-01-01

    Early on during word recognition, letter positions are not accurately coded. Evidence for this comes from transposed-letter (TL) priming effects, in which letter strings generated by transposing two adjacent letters (e.g., "jugde") produce large priming effects, more than primes with the letters replaced in the corresponding position (e.g.,…

  20. From Numbers to Letters: Feedback Regularization in Visual Word Recognition

    ERIC Educational Resources Information Center

    Molinaro, Nicola; Dunabeitia, Jon Andoni; Marin-Gutierrez, Alejandro; Carreiras, Manuel

    2010-01-01

    Word reading in alphabetic languages involves letter identification, independently of the format in which these letters are written. This process of letter "regularization" is sensitive to word context, leading to the recognition of a word even when numbers that resemble letters are inserted among other real letters (e.g., M4TERI4L). The present…

  1. Evolutionary theory in letters to the editor.

    PubMed

    Silva, Eric Orion; Lowe, Clayton Cory

    2015-05-01

    This research note presents the results of a content analysis of 234 letters to the editors that discuss evolutionary theory and were published in American newspapers. We find that letters to the editor both support and hinder the cause of teaching evolutionary theory in American secondary schools. On the one hand, anti-evolutionary theory messages are marginalized in the letters section. This marginalization signals a low level of legitimacy for creationism. It might also contribute to the sense of tension that sustains creationist identities. On the other hand, relatively few letters explicitly note the fact that scientists or the scientific community accept evolution. Interestingly, the obscuration of the scientific community's support for evolutionary theory occurs both in letters supporting and opposing evolutionary theory.

  2. Neural correlate of vernier acuity tasks assessed by functional MRI (FMRI).

    PubMed

    Sheth, Kevin N; Walker, B Michael; Modestino, Edward J; Miki, Atsushi; Terhune, Kyla P; Francis, Ellie L; Haselgrove, John C; Liu, Grant T

    2007-01-01

    Vernier acuity refers to the ability to discern a small offset within a line. However, while Vernier acuity has been extensively studied psychophysically, its neural correlates are uncertain. Based upon previous psychophysical and electrophysiologic data, we hypothesized that extrastriate areas of the brain would be involved in Vernier acuity tasks, so we designed event-related functional MRI (fMRI) paradigms to identify cortical regions of the brain involved in this behavior. Normal subjects identified suprathreshold and subthreshold Vernier offsets. The results suggest a cortical network including frontal, parietal, occipital, and cerebellar regions subserves the observation, processing, interpretation, and acknowledgment of briefly presented Vernier offsets.

  3. Visual acuity loss and OCT changes as initial signs of leukaemia

    PubMed Central

    Ortiz, Jose M; Ruiz-Moreno, Jose M; Pozo-Martos, Paola; Montero, Javier A

    2010-01-01

    AIM To report two cases where decreased visual acuity was the first symptom of leukaemia and optical coherence tomography (OCT) allowed identification and localization of the retinal lesions. METHODS Retrospective, interventional, case reports. RESULTS One case of lymphoblastic acute leukaemia and chronic lymphoid leukaemia were diagnosed following decreased visual acuity. OCT showed macular serous detachment in the first case. The second case presented hypo fluorescent retinal infiltrates which appeared as hyper reflective lesions by OCT. Retinal changes disappeared and visual acuity was recovered following complete remission of the neoplasm. CONCLUSION OCT is a valuable, non invasive diagnostic tool permitting detection, localization and follow-up of ocular dissemination of neoplasms. PMID:22553573

  4. Tactile roughness discrimination threshold is unrelated to tactile spatial acuity.

    PubMed

    Libouton, Xavier; Barbier, Olivier; Plaghki, Leon; Thonnard, Jean-Louis

    2010-04-02

    The present study examined the relationship between the tactile roughness discrimination threshold (TRDT) and the tactile spatial resolution threshold (TSRT) at the index fingertip in humans. A new device was built for measuring TRDT, allowing pair-wise presentations of two sets of six different sandpaper grits. The smoothest grits ranged from 18 to 40 microm and the roughest grits ranged from 50 to 195 microm particle size. The reference sandpaper had a 46 microm particle size. A two-alternative forced choice paradigm and a double interlaced adaptive staircase procedure yielding a 75% just noticeable difference (75%jnd) was used according to Zwislocki and Relkin. Contact force and scanning velocity were measured at the fingertip with a built-in sensor. The TSRT was assessed with an extended set of grating domes. Fifty-three male and female subjects, spanning a wide age range participated in this study. The JND75% or TRDT was lower for the smoothest sandpapers (15+/-8.5 microm) compared to the roughest sandpapers (44+/-32.5 microm). TRDT performance was unrelated to age or gender. Additionally, grit size had no effect on the mean forces (normal and tangential) exerted at the fingertip or the mean scan velocities. In contrast, there was a significant degradation of TSRT performance with age. Lastly, there was no significant correlation between TRDT and TRST performance. Results of this study support the theory that the neural mechanisms underlying the perception of tactile roughness discrimination for fine textures differ from those involved in spatial resolution acuity often associated with the SA1 afferents.

  5. Search for letter identity and location by disabled readers.

    PubMed

    Enns, J T; Bryson, S E; Roes, C

    1995-09-01

    Reading-disabled boys, reading- and age-matched controls, and adults searched letter arrays for the identity or location of a probe letter. Response time (RT) and accuracy were examined as a function of the temporal relation between probe and array letters (probe first, simultaneous, array first), and array size (1-5 letters). Although disabled readers closely resembled age controls in RT, their accuracy differed significantly when large letter arrays were tested. In the letter identification task, this was only evident when the array letters preceded the probe; in the letter location task, it occurred in all three probe conditions. Correlational analyses showed that all subjects were influenced by the visual, but not the phonological, similarity between letters. Thus, a reading-related impairment is evident in both letter identification and letter location processes, even when the phonological coding of letters has been minimized.

  6. A single cohort prospective trial of the immediate effects of spinal manipulation on visual acuity

    PubMed Central

    Athaide, Michelle; Rego, Carol; Budgell, Brian

    2016-01-01

    Introduction: There is no high quality evidence on which to judge the generalizability of isolated reports of improvement in vision following manipulation. The current paucity of research results also precludes the thoughtful design of a controlled, prospective clinical study. Hence, the purpose of the current study was to test the feasibility of conducting a clinical trial of the acute effects of spinal manipulation on visual acuity. Methods: New adult patients presenting to a community based chiropractic clinic were recruited into a single cohort prospective trial to determine the immediate effects of cervical spinal manipulation on visual acuity. Results: The experimental protocol was well accepted by patients and caused minimal or no disruption of the clinic routine. By some measures, chiropractic treatment was accompanied by statistically significant improvements in visual acuity. Discussion: The results of this study indicate that it is quite feasible to conduct a prospective, community based clinical study of the acute effects of spinal manipulation on visual acuity. PMID:27069271

  7. Night vision goggle visual acuity assessment: results of an interagency test

    NASA Astrophysics Data System (ADS)

    Task, H. Lee

    2001-08-01

    There are several parameters that are used to characterize the quality of a night vision goggle (NVG) such as resolution, gain, field-of-view, visual acuity, etc. One of the primary parameters is visual acuity or resolution of the NVG. These two terms are often used interchangeably primarily because of the measurement methods employed. The objectives of this paper are to present: (1) an argument as to why NVG visual acuity and resolution should be considered as distinctly different parameters, (2) descriptions of different methods of measuring visual acuity and resolution, and (3) the results of a blind test by several agencies to measure the resolution of the same two NVGs (four oculars).

  8. Statistical mechanics of letters in words

    NASA Astrophysics Data System (ADS)

    Stephens, Greg J.; Bialek, William

    2010-06-01

    We consider words as a network of interacting letters, and approximate the probability distribution of states taken on by this network. Despite the intuition that the rules of English spelling are highly combinatorial and arbitrary, we find that maximum entropy models consistent with pairwise correlations among letters provide a surprisingly good approximation to the full statistics of words, capturing ˜92% of the multi-information in four-letter words and even “discovering” words that were not represented in the data. These maximum entropy models incorporate letter interactions through a set of pairwise potentials and thus define an energy landscape on the space of possible words. Guided by the large letter redundancy we seek a lower-dimensional encoding of the letter distribution and show that distinctions between local minima in the landscape account for ˜68% of the four-letter entropy. We suggest that these states provide an effective vocabulary which is matched to the frequency of word use and much smaller than the full lexicon.

  9. Statistical mechanics of letters in words.

    PubMed

    Stephens, Greg J; Bialek, William

    2010-06-01

    We consider words as a network of interacting letters, and approximate the probability distribution of states taken on by this network. Despite the intuition that the rules of English spelling are highly combinatorial and arbitrary, we find that maximum entropy models consistent with pairwise correlations among letters provide a surprisingly good approximation to the full statistics of words, capturing ∼92% of the multi-information in four-letter words and even "discovering" words that were not represented in the data. These maximum entropy models incorporate letter interactions through a set of pairwise potentials and thus define an energy landscape on the space of possible words. Guided by the large letter redundancy we seek a lower-dimensional encoding of the letter distribution and show that distinctions between local minima in the landscape account for ∼68% of the four-letter entropy. We suggest that these states provide an effective vocabulary which is matched to the frequency of word use and much smaller than the full lexicon.

  10. EDITORIAL: Letter from the Editor Letter from the Editor

    NASA Astrophysics Data System (ADS)

    Pashinin, Pavel P.

    2013-01-01

    Dear readers, contributors, and members of the world laser physics community. It is a great honour for us to introduce to you our new publishing partner, IOP Publishing, a subsidiary of the Institute of Physics, United Kingdom. IOP Publishing is a world renowned authority in producing journals, magazines, websites and services that enable researchers and research organizations to present their work to a world-wide audience. Laser Physics, the first English-language scientific journal in Russia, was founded in 1990 on the initiative of Alexander M Prokhorov, a pioneer and leader in laser physics research. Professor Prokhorov served as the first Editor-in-Chief of the journal until 2002. We are proud that it is our 23rd year of publishing Laser Physics and our 10th year of publishing Laser Physics Letters. We would like to honour the memory of our friend, late Professor Igor Yevseyev, whose enthusiasm and unwavering dedication to our journals contributed most significantly to their success. It was initially his idea in 2011 to approach IOP with a partnership proposal. We deeply regret that he is no longer with us as we enter this productive alliance. Now, in partnership with IOP, we are turning a new page in providing world-wide access to the cutting-edge research results in our journals, serving our well established global audience. We see new horizons opening for our journals for years to come and hope that our readers share our enthusiasm and aspirations. Please accept our best wishes for all your new scientific endeavors in the exciting field of laser physics.

  11. Implementing an obstetric triage acuity scale: interrater reliability and patient flow analysis.

    PubMed

    Smithson, David S; Twohey, Rachel; Rice, Tim; Watts, Nancy; Fernandes, Christopher M; Gratton, Robert J

    2013-10-01

    A 5-category Obstetric Triage Acuity Scale (OTAS) was developed with a comprehensive set of obstetrical determinants. The objectives of this study were as follows: (1) to test the interrater reliability of OTAS and (2) to determine the distribution of patient acuity and flow by OTAS level. To test the interrater reliability, 110 triage charts were used to generate vignettes and the consistency of the OTAS level assigned by 8 triage nurses was measured. OTAS performed with substantial (Kappa, 0.61 - 0.77, OTAS 1-4) and near perfect correlation (0.87, OTAS 5). To assess patient flow, the times to primary and secondary health care provider assessments and lengths of stay stratified by acuity were abstracted from the patient management system. Two-thirds of triage visits were low acuity (OTAS 4, 5). There was a decrease in length of stay (median [interquartile range], minutes) as acuity decreased from OTAS 1 (120.0 [156.0] minutes) to OTAS 3 (75.0 [120.8]). The major contributor to length of stay was time to secondary health care provider assessment and this did not change with acuity. The percentage of patients admitted to the antenatal or birthing unit decreased from 80% (OTAS 1) to 12% (OTAS 5). OTAS provides a reliable assessment of acuity and its implementation has allowed for triaging of obstetric patients based on acuity, and a more in-depth assessment of the patient flow. By standardizing assessment, OTAS allows for opportunities to improve performance and make comparisons of patient care and flow across organizations.

  12. Grating Visual Acuity Results in the Early Treatment for Retinopathy of Prematurity Study

    PubMed Central

    2015-01-01

    Objective To compare grating (resolution) visual acuity at 6 years of age in eyes that received early treatment (ET) for high-risk prethreshold retinopathy of prematurity (ROP) versus eyes that were managed conventionally (CM). Methods In a randomized clinical trial, infants with bilateral, high-risk prethreshold ROP (N=317) had one eye treated early at high-risk prethreshold disease and the other eye managed conventionally, and treated if ROP progressed to threshold severity. For asymmetric cases (N=84), the high-risk prethreshold eye was randomized to either ET or CM. Main Outcome Measures Grating visual acuity measured at 6 years of age by masked testers using Teller acuity cards. Results Monocular grating acuity results were obtained from 317 (86%) of 370 surviving children. Analysis of grating acuity results for all subjects with high-risk prethreshold ROP showed no statistically significant overall benefit for early treatment (18.1% vs 22.8% unfavorable outcome, P=0.08). When the 6-year grating acuity results were analyzed according to a clinical algorithm (high-risk Type 1 and high-risk Type 2 prethreshold ROP), a benefit was seen in Type 1 eyes (16.4% vs 25.2%, P=0.004) that were treated early, but not in Type 2 eyes (21.3% vs 15.9%, P=0.29). Conclusion Early treatment for eyes with Type 1 ROP improved grating acuity outcomes but early treatment for eyes with Type 2 ROP did not. Application to Clinical Medicine Type I eyes should be treated early; however, based on acuity results at age 6 years, Type 2 eyes should be cautiously monitored for progression to Type 1 ROP. Trial Registration NCT00027222 PMID:21746974

  13. Visual Acuity Testing: Feedback Affects Neither Outcome nor Reproducibility, but Leaves Participants Happier

    PubMed Central

    Bach, Michael; Schäfer, Kerstin

    2016-01-01

    Assessment of visual acuity is a well standardized procedure at least for expert opinions and clinical trials. It is often recommended not giving patients feedback on the correctness of their responses. As this viewpoint has not been quantitatively examined so far, we quantitatively assessed possible effects of feedback on visual acuity testing. In 40 normal participants we presented Landolt Cs in 8 orientations using the automated Freiburg Acuity Test (FrACT, acuity threshold was measured with an adaptive staircase procedure. In an ABCDDCBA scheme, trial-by-trial feedback was provided in 2 x 4 conditions: (A) no feedback, (B) acoustic signals indicating correctness, (C)visual indication of correct orientation, and (D) a combination of (B) and (C). After each run the participants judged comfort. Main outcome measures were absolute visual acuity (logMAR), its test-retest agreement (limits of agreement) and participants’ comfort estimates on a 5-step symmetric Likert scale. Feedback influenced acuity outcome significantly (p = 0.02), but with a tiny effect size: 0.02 logMAR poorer acuity for (D) compared to (A), even weaker effects for (B) and (C). Test-retest agreement was high (limits of agreement: ± 1.0 lines) and did not depend on feedback (p>0.5). The comfort ranking clearly differed, by 2 steps on the Likert scale: the condition (A)–no feedback–was on average “slightly uncomfortable”, the other three conditions were “slightly comfortable” (p<0.0001). Feedback affected neither reproducibility nor the acuity outcome to any relevant extent. The participants, however, reported markedly greater comfort with any kind of feedback. We conclude that systematic feedback (as implemented in FrACT) offers nothing but advantages for routine use. PMID:26824693

  14. The Effect of Signal-to-Noise Ratio on Visual Acuity Through Night Vision Goggles

    DTIC Science & Technology

    1991-02-01

    subjects in visuLal acuity performance with NVGs, it was concluded that further research should be conducted to examine the correlation between visual...the image intensifier tuho. Tile image intensifier tube is basically a light amplifier that is sensitive over tho spectral region of about 600nm to... excellent means of getting a sensitive measure of visual acuity. 2 Method 2.1 Subje;cts Twelve male volunteers participated in this study. ’he subjects

  15. Quantum key distribution with multi letter alphabets

    NASA Astrophysics Data System (ADS)

    Sych, D.; Leuchs, G.

    2010-03-01

    We present a new protocol for continuous variable quantum key distribution (CV QKD). The novelty of the protocol is a multi letter alphabet represented by coherent states of light with a fixed amplitude and variable phase. Information is encoded in the phase of a coherent state which can be chosen from a regular discrete set consisting, however, of an arbitrary number of letters. We evaluate the security of the protocol against the beam splitting attack. As a result we show the proposed protocol has advantages over the standard two letter coherent state QKD protocol, especially in the case when losses in the communication channel are low.

  16. 15 CFR 908.13 - Address of letters.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... SUBMITTING REPORTS ON WEATHER MODIFICATION ACTIVITIES § 908.13 Address of letters. Letters and other communications intended for the Administrator, in connection with weather modification reporting or...

  17. Early non-visual experience influences proprioceptive-spatial discrimination acuity in adulthood.

    PubMed

    Fiehler, Katja; Reuschel, Johanna; Rösler, Frank

    2009-02-01

    The present study tested whether non-visual spatial experience affects later acuity of space perception. Congenitally blind adults who differed in the age acquired spatial knowledge via an orientation and mobility (O&M) training and matched sighted controls performed passive arm movements and judged the direction of the sensed movement. Proprioceptive-spatial discrimination acuity was assessed by an adaptive psychophysical procedure in two spatial coding conditions. In the egocentric coding condition, participants judged whether the hand trajectory felt left- or right-tilted in reference to a straight trajectory aligned to the transverse horizontal plane of the body midline axis. In the allocentric coding condition, they indicated whether the hand trajectory felt acute- or obtuse-angled in reference to a right angle. Proprioceptive-spatial acuity of congenitally blind participants significantly covaried with the age they attended an O&M training. The earlier the congenitally blind participants started the O&M training the more accurate was their space perception. Congenitally blind participants who underwent an O&M training after the age of 12 years showed poorer acuity than sighted controls. Congenitally blind participants with an earlier O&M training, however, approached the performance level of the sighted controls. The observed improvement in spatial acuity was more pronounced when judgements were given on the basis of an allocentric than an egocentric frame of reference. These findings suggest that proprioceptive-spatial acuity in adulthood depends on non-visual spatial experience during early development.

  18. Plasticity of Binocularity and Visual Acuity Are Differentially Limited by Nogo Receptor

    PubMed Central

    Stephany, Céleste-Élise; Chan, Leanne L.H.; Parivash, Sherveen N.; Dorton, Hilary M.; Piechowicz, Mariel

    2014-01-01

    The closure of developmental critical periods consolidates neural circuitry but also limits recovery from early abnormal sensory experience. Degrading vision by one eye throughout a critical period both perturbs ocular dominance (OD) in primary visual cortex and impairs visual acuity permanently. Yet understanding how binocularity and visual acuity interrelate has proven elusive. Here we demonstrate the plasticity of binocularity and acuity are separable and differentially regulated by the neuronal nogo receptor 1 (NgR1). Mice lacking NgR1 display developmental OD plasticity as adults and their visual acuity spontaneously improves after prolonged monocular deprivation. Restricting deletion of NgR1 to either cortical interneurons or a subclass of parvalbumin (PV)-positive interneurons alters intralaminar synaptic connectivity in visual cortex and prevents closure of the critical period for OD plasticity. However, loss of NgR1 in PV neurons does not rescue deficits in acuity induced by chronic visual deprivation. Thus, NgR1 functions with PV interneurons to limit plasticity of binocularity, but its expression is required more extensively within brain circuitry to limit improvement of visual acuity following chronic deprivation. PMID:25164659

  19. Correlation analysis of proprioceptive acuity in ipsilateral position-matching and velocity-discrimination.

    PubMed

    Djupsjöbacka, Mats; Domkin, Dmitry

    2005-01-01

    In order to plan and control movements the central nervous system (CNS) needs to continuously keep track of the state of the musculoskeletal system. Therefore the CNS constantly uses sensory input from mechanoreceptors in muscles, joints and skin to update information about body configuration on different levels of the CNS. On the conscious level, such representations constitute proprioception. Different tests for assessment of proprioceptive acuity have been described. However, it is unclear if the proprioceptive acuity measurements in these tests correlate within subjects. By using both uni- and multivariate analysis we compared proprioceptive acuity in different variants of ipsilateral active and passive limb position-matching and ipsilateral passive limb movement velocity-discrimination in a group of healthy subjects. The analysis of the position-matching data revealed a higher acuity of matching for active movements in comparison to passive ones. The acuity of matching was negatively correlated to movement extent. There was a lack of correlation between proprioceptive acuity measurements in position-matching and velocity-discrimination.

  20. Effects of molting on the visual acuity of the blue crab, Callinectes sapidus.

    PubMed

    Baldwin, Jamie; Johnsen, Sönke

    2011-09-15

    In crustaceans with compound eyes, the corneal lens of each facet is part of the exoskeleton and thus shed during molting. Here we used an optomotor assay to evaluate the impact of molting on visual acuity (as measured by the minimum resolvable angle, α(min)) in the female blue crab, Callinectes sapidus. We found that visual acuity decreases substantially in the days prior to molting and is gradually recovered after molting. Four days prior to molting, α(min) was 1.8 deg (N=5), a value approximating the best possible acuity in this species. In the 24 h before ecdysis occurred, α(min) increased to 15.0 deg (N=12), corresponding to an eightfold drop in visual acuity. Within 6 days after molting, α(min) returned to the pre-molting value. Micrographs of C. sapidus eyes showed that a gap between the corneal lens and the crystalline cone first appeared approximately 5 days prior to shedding and increased in width as the process progressed. This separation was likely responsible for the loss of visual acuity observed in behavioral tests. In blue crabs, mating is limited to the period of the female's pubertal molt, and a reduction in acuity during this time may have an effect on the sensory cues used in female mate choice. The results described here may be broadly applicable to all arthropods that molt and have particular importance for crustaceans that molt multiple times in their lifetime or have mating cycles that are paired with molting.

  1. A novel computer software for the evaluation of dynamic visual acuity

    PubMed Central

    Quevedo, Lluïsa; Aznar-Casanova, José Antonio; Merindano-Encina, Dolores; Cardona, Genís; Solé-Fortó, Joan

    2012-01-01

    Purpose Dynamic visual acuity (DVA) is defined as the ability to discriminate fine details in a moving target. Albeit a growing interest in DVA, there is a lack of standardized, validated instrumentation and procedures for the assessment of this visual function parameter. The aim of the present study was to analyze qualitative construct validity and test–retest reliability of a novel, computer-assisted instrument (DinVA 3.0) for the measurement of DVA. Methods Two different experiments are presented, involving the participation of 33 subjects. The first experiment aimed at testing qualitative construct validity of the DinVA 3.0 by comparing the outcome of a series of trials consisting in different speeds, contrasts and trajectories of the target stimuli with those reported in the literature. The second experiment assessed test–retest reliability by repeating a series of trials at three different time intervals, at maximum target stimuli contrast and either high or low speed configurations. Results The results of the first experiment gave support to the qualitative construct validity of DinVA 3.0, as the DVA scores were found to be modulated by the speed of the moving target (high speeds yielded lower DVA), contrast (high contrast resulted in better DVA) and trajectory (DVA was better at horizontal rather than oblique trajectories). Test–retest reliability was found to be good, with a small insignificant trend towards improvement with learning. Conclusion The DinVA 3.0 proved to be a valid and reliable instrument for the assessment of DVA and may be considered a promising tool for both clinicians and researchers.

  2. Letter to Dr. Felix Bronner

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.; Dalton, Bonnie (Technical Monitor)

    2002-01-01

    Dear Dr. Bronner: I have been reading in The Physiologist the letters from senior physiologists for many years with great interest. It is impressive that many of the respondents are still pursuing scientific endeavours in their 70's and some even in their 80's. The interesting task is to ponder the relative causative proportions of heredity and environment responsible. One wonders whether knowing something about physiology engenders longer and more productive lives? I suspect so because of the accompanying self-discipline. But another factor would seem to be the pervasive joy of working in this profession. I have been fortunate to be able to acquire the joy of physiology during my graduate studies at Illinois, and to have been able to carry it over here at NASA, Ames Research Center for the past 40 years. A truly academic style research environment at a federal research center is rare. The trick to a joyous research career is to overcome those ever-present slings and arrows of outrageous fortune with dignity whenever possible. To that end I have found solace and guidance in reading the history of warfare and its leaders, especially Sun Tsu's The Art of War and Clauswitz's On War. I became eligible for retirement in 1993, but to insure domestic tranquility and also the joy of pursuing my research hobby have continued working in the laboratory on human research. It is troubling to see that funding for individual scientists conducting human research is declining rapidly, along with their new ideas; perhaps the old ones are more comfortable. Hopefully I can provide a similar response when I'm 80! Thanks for your interest. Sincerely, John Greenleaf

  3. A letter from Janet Benshoof.

    PubMed

    Benshoof, J

    1997-06-06

    This letter to readers of "Reproductive Freedom News" criticizes the American Medical Association's (AMA) Board of Trustees for endorsing a bill in the US Senate that would ban "partial-birth" abortions and allow the imprisonment of physicians who perform the procedure. The decision of the Board of Trustees was made in total disregard to the AMA bylaws, because the decision ran counter to the recommendations of an AMA task force that concluded that the AMA should take no action on this bill but seek to preserve the ability of physicians to use their discretion in providing medical care and the viability line in abortion legislation. The proposed criminal ban fails to contain a viability line; provides no exception to protect a woman's health, medical choice, or safety; and provides no exception in cases of fetal anomaly. The action by the Board of Trustees seriously undermines the work of the Center for Reproductive Law and Policy and gives abortion opponents ammunition to mount a serious challenge to the Roe vs. Wade decision. The AMA endorsement goes beyond simply stating that the procedure should never be used; it endorses giving physicians who perform such abortions, for whatever reason, prison terms. This position undermines two critical principles long upheld by the AMA: 1) that physicians must be able to carry out their medical responsibilities free from government interference and 2) that women have a fundamental right to decide on the appropriate provision of abortion services within their physician-patient relationship. The damage from this endorsement can and should be undone by the AMA's House of Delegates at their meeting in June 1997.

  4. 2006 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    These letters to and from Administrator Stephen Johnson are regarding risks from polybrominated biphenyl ethers (PBEs), the Voluntary Children's Chemical Evaluation Project, perchlorate PRG and water contamination, and NAAQS for particulate matter.

  5. 2007 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    These letters to and from Administrator Stephen Johnson are regarding mutagenic mode of action, carcinogenicity, NAAQS for ozone, evaluating existing and new chemicals, research translation, and NAAQS for lead.

  6. Gender bias found in recommendation letters

    NASA Astrophysics Data System (ADS)

    Kruesi, Liz

    2016-11-01

    Female postdoctoral fellowship applicants are half as likely as their male counterparts to receive glowing recommendation letters, according to a study by researchers at Columbia University's Lamont-Doherty Earth Observatory (LDEO).

  7. A Letter to Gabriela, A Young Writer.

    ERIC Educational Resources Information Center

    Mora, Pat

    1990-01-01

    Presents a letter written by a professional writer (and a former high school and college teacher) to a young female student who has started writing poems. Discusses why and how she writes. Urges the student to continue writing. (RS)

  8. Resource Letter ETC-1: extraterrestrial civilization.

    PubMed

    Kuiper, T B; Brin, G D

    1989-01-01

    This Resource Letter provides a guide to the literature about intelligent life beyond the human sphere of exploration. It offers a starting point for professionals and academics interested in participating in the debate about the existence of other technological civilizations or in the search for extraterrestrial intelligence (SETI). It can also serve as a reference for teaching. This Letter is not intended as an exhaustive bibliography, but several extensive bibliographies have been cited. The letter E after an item indicates elementary, nontechnical material of general interest to persons becoming informed in the field. Intermediate level material, of a somewhat more specialized nature, is indicated by the Letter I. The annotation A indicates advanced, technical material. An asterisk (*) precedes items to be included in an accompanying Reprint Book.

  9. Relative Width and Height of Handwritten Letter.

    PubMed

    Lizega Rika, Joseba

    2017-02-28

    This is an exploratory study that analyzes the width and the height of letters in two texts written by each of the 21 writers analyzed. After detrending the linear, text, and allograph trends, we proceeded to comparing the sizes obtained in different texts. The different detrended series were compared by means of correlation and t-test. According to the results regarding the width of letters, the texts of 19 of 21 writers correlated strongly, whereas the texts of two writers did not correlate with the limits of the threshold. With regard to the height of letters, texts written by between 18 and 21 writers of 21 writers correlated strongly, whereas texts that did not correlate were within the threshold value. Regarding both the width and the height of letters, of 21 writers, texts written by between 19 and 21 individuals were found to correlate strongly.

  10. Fogger and Mister Final Signed Letter

    EPA Pesticide Factsheets

    EPA has asked pesticide companies to provide data or amend registrations of products claiming to control public health microorganisms when applied by fogging and/or misting methods. The letter further describes the ways in which the company may respond.

  11. 49 CFR 190.205 - Warning letters.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY PIPELINE SAFETY PROGRAMS AND RULEMAKING..., OPS, may issue a Warning Letter notifying the owner or operator of the probable violation and...

  12. 49 CFR 190.205 - Warning letters.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY PIPELINE SAFETY PROGRAMS AND RULEMAKING..., OPS, may issue a Warning Letter notifying the owner or operator of the probable violation and...

  13. 49 CFR 190.205 - Warning letters.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY PIPELINE SAFETY PROGRAMS AND RULEMAKING..., OPS, may issue a Warning Letter notifying the owner or operator of the probable violation and...

  14. Scientists' Letter Supports Climate Change Panel

    NASA Astrophysics Data System (ADS)

    Chell, Kaitlin

    2010-03-01

    Recent media coverage about climate change has focused on errors in the 2007 Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) and other concerns. In light of this media coverage, an open letter sent on 12 March to members of the U.S. Congress and various U.S. federal agencies in support of the IPCC has been signed (at Eos press time) by more than 250 U.S. scientists. The letter lays out the IPCC process and also examines climate science findings since the publication of AR4. “Our goal with this letter is to demonstrate the strong support that exists within the scientific community for the IPCC and its main findings,” Gary Yohe of Wesleyan University noted in a press release issued about the letter.

  15. 2004 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    Most of these letters are to Administrator Leavitt, regarding school environments, risks due to polybrominated diphenyl ethers (PBDEs), mercury emissions, fish advisory, cancer susceptibility, pollution from power plants, and the National Children's Study.

  16. Einstein/Roosevelt Letters: A Unit.

    ERIC Educational Resources Information Center

    Bodle, Walter S.

    1985-01-01

    The letters in this unit of study intended for secondary students are facsimile reproductions of the correspondence between Albert Einstein and President Roosevelt on the possibility of constructing an atomic bomb. Classroom activities are also suggested. (RM)

  17. 2010 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    Letters to and from Administrator Jackson, also including a report from CHPAC's school siting task group, address school siting guidelines issues as well as response to a National Research Council (NRC) report on risk assessment.

  18. 2012 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    These two letters address National Ambient Air Quality Standards proposed for particulate matter (PM), and childhood lead poisoning prevention particularly as regards revision of the Integrated Exposure Uptake Biokinetic model.

  19. 2005 Children's Health Protection Advisory Committee Letters

    EPA Pesticide Factsheets

    These letters, mainly to and from Administrators Stephen Johnson, regard the Clean Air Mercury Rule, Particulate Matter National Ambient Air Quality Standards, cancer susceptibility, fish consumption advisories, human subjects, hurricanes, and pesticides.

  20. Blue Ribbon Panel Report Cover Letter

    Cancer.gov

    The letter from NCI Acting Director Douglas R. Lowy, M.D., to Vice President Biden that accompanied the Blue Ribbon Panel final report, thanking the Vice President for his commitment to and leadership of the Cancer Moonshot.

  1. Resource Letter SW1: Space Weather

    NASA Astrophysics Data System (ADS)

    Baker, Daniel N.; Lanzerotti, Louis J.

    2016-03-01

    This Resource Letter describes the phenomena and effects on technological systems that are known collectively as space weather. A brief history of the topic is provided, and the scientific understandings of drivers for such phenomena are discussed. The impacts of space disturbances are summarized, and the strategies for dealing with space weather threats are examined. The Resource Letter concludes with description of approaches that have been proposed to deal with threats to our increasingly technological society.

  2. Letter to the Editor: Robert W. Evans

    NASA Astrophysics Data System (ADS)

    Johnston, A.

    2000-12-01

    I read the Letters page of the latest issue of the JBAA (2000 October) with some amusement. My very good friend Bob Evans had, according to the letter header, not only been elevated to the clergy, but had also transferred his nationality from Kiwi to Aussie. While he'll probably overlook the religious error he may not be so sanguine about being mistaken for an Australian.

  3. Assessing the influence of letter position in reading normal and transposed texts using a letter detection task.

    PubMed

    Guérard, Katherine; Saint-Aubin, Jean; Poirier, Marie; Demetriou, Constantina

    2012-12-01

    During word recognition, some letters appear to play a more important role than others. Although some studies have suggested that the first and last letters of a word have a privileged status, there is no consensus with regards to the importance of the different letter positions when reading connected text. In the current experiments, we used a simple letter search task to examine the impact of letter position on word identification in connected text using a classic paper and pencil procedure (Experiment 1) and an eye movement monitoring procedure (Experiment 2). In Experiments 3 and 4, a condition with transposed letters was included. Our results show that the first letter of a word is detected more easily than the other letters, and transposing letters in a word revealed the importance of the final letter. It is concluded that both the initial and final letters play a special role in word identification during reading but that the underlying processes might differ.

  4. Ankle proprioceptive acuity is associated with objective as well as self-report measures of balance, mobility, and physical function.

    PubMed

    Deshpande, Nandini; Simonsick, Eleanor; Metter, E Jeffrey; Ko, Seunguk; Ferrucci, Luigi; Studenski, Stephanie

    2016-06-01

    Ankle proprioceptive information is integrated by the central nervous system to generate and modulate muscle contractions for maintaining standing balance. This study evaluated the association of ankle joint proprioception with objective and self-report measures of balance, mobility, and physical function across the adult life span. Seven hundred and ninety participants (age range 24-97 years, 362 women) who completed ankle proprioception assessment between 2010 and 2014 were included in the present study from the population-based cohort of the Baltimore Longitudinal Study of Aging (BLSA), USA. Outcome measures included ankle joint proprioception measured as threshold for perception of passive movement (TPPM); single leg stance time; perceived difficulty for standing balance; usual, fastest, and narrow-path gait speed; walking index; short physical performance battery score; and self-reported activity restriction due to fear of falling. Descriptive variables included age, sex, body mass index, education, strength, and cognition. Analyses of covariance (ANCOVA) in general linear model (GLM) or multinomial logistic regression analyses were performed, as appropriate, to test the hypothesis that balance, mobility, and physical function were significantly different according to TPPM quintiles even after adjusting for relevant covariates. Those with TPPM >2.2° consistently demonstrated poor balance, mobility, and physical function. However, with increase in challenge (single leg stance, fastest walking speed, and SPPB), TPPM >1.4° was associated with significantly worse performance. In conclusion, ankle proprioceptive acuity has an overall graded relationship with objective and self-report measures of balance, mobility, and physical function. However, the cutoff proprioceptive acuity associated with substantial decline or inability to perform could depend on the challenge induced.

  5. Measuring the Influence of Galilean Loupe System on Near Visual Acuity of Dentists under Simulated Clinical Conditions

    PubMed Central

    Urlic, Iris; Verzak, Željko; Vranic, Dubravka Negovetic

    2016-01-01

    Aim The purpose of this study was to compare near visual acuity of dentists without optical aids (VSC) with near visual acuity of those using the Galilean telescope system (VGA2) with magnification of x 2.5, and the distance of 350 mm in simulated clinical conditions. Methods The study included 46 dentists (visual acuity 1.0 without correction). A visual acuity testing was carried out using a miniaturized Snellen visual acuity chart which was placed in the cavity of molar teeth mounted in a phantom head in simulated clinical conditions. Near visual acuity for the vicinity was examined: 1) without correction at a distance of 300-400 mm (VSC); 2) with Galilean loupes with magnification of x2.5, focal length of 350mm. Results The distributions of near visual acuity recorded using VSC and VGA2, 5 systems were compared by the Wilcoxon Signed Rank test. The results obtained by Wilcoxon Signed Rank test pointed to a statistically significant difference in the distribution of recorded visual acuity between the VSC and VGA2 optical systems (W = - 403.5; p <0.001). Conclusion If using the VGA2, 5 systems, higher values of the near visual acuity were recorded and subsequently compared to near visual acuity without magnifying aids (VSC). PMID:27847397

  6. Effect of Target Location on Dynamic Visual Acuity During Passive Horizontal Rotation

    NASA Technical Reports Server (NTRS)

    Appelbaum, Meghan; DeDios, Yiri; Kulecz, Walter; Peters, Brian; Wood, Scott

    2010-01-01

    The vestibulo-ocular reflex (VOR) generates eye rotation to compensate for potential retinal slip in the specific plane of head movement. Dynamic visual acuity (DVA) has been utilized as a functional measure of the VOR. The purpose of this study was to examine changes in accuracy and reaction time when performing a DVA task with targets offset from the plane of rotation, e.g. offset vertically during horizontal rotation. Visual acuity was measured in 12 healthy subjects as they moved a hand-held joystick to indicate the orientation of a computer-generated Landolt C "as quickly and accurately as possible." Acuity thresholds were established with optotypes presented centrally on a wall-mounted LCD screen at 1.3 m distance, first without motion (static condition) and then while oscillating at 0.8 Hz (DVA, peak velocity 60 deg/s). The effect of target location was then measured during horizontal rotation with the optotypes randomly presented in one of nine different locations on the screen (offset up to 10 deg). The optotype size (logMar 0, 0.2 or 0.4, corresponding to Snellen range 20/20 to 20/50) and presentation duration (150, 300 and 450 ms) were counter-balanced across five trials, each utilizing horizontal rotation at 0.8 Hz. Dynamic acuity was reduced relative to static acuity in 7 of 12 subjects by one step size. During the random target trials, both accuracy and reaction time improved proportional to optotype size. Accuracy and reaction time also improved between 150 ms and 300 ms presentation durations. The main finding was that both accuracy and reaction time varied as a function of target location, with greater performance decrements when acquiring vertical targets. We conclude that dynamic visual acuity varies with target location, with acuity optimized for targets in the plane of motion. Both reaction time and accuracy are functionally relevant DVA parameters of VOR function.

  7. Five-year visual acuity outcomes and injection patterns in patients with pro-re-nata treatments for AMD, DME, RVO and myopic CNV

    PubMed Central

    Wecker, Thomas; Ehlken, Christoph; Bühler, Anima; Lange, Clemens; Agostini, Hansjürgen; Böhringer, Daniel; Stahl, Andreas

    2017-01-01

    Background Anti vascular endothelial growth factor (VEGF) therapy is an established treatment for various retinal diseases. Long-term data on injection frequencies and visual acuity (VA), however, are still rare. Methods Five-year analysis of real-life VA developments and injection patterns from 2072 patients (2577 eyes; 33 187 injections) with chronically active disease undergoing pro-re-nata treatment for age-related macular degeneration (AMD), diabetic macular oedema (DME), retinal vein occlusion (RVO) and myopic choroidal neovascularisation (CNV). Results Maximum mean VA gain in year 1 was+5.2 letters in AMD, +6.2 in DME, +10 in RVO and+7.2 in myopic CNV. Over 5 years, however, VA in patients with AMD declined. By year 5, 34% of patients with AMD had experienced VA loss of >15 letters, 56% had remained stable and 10% had gained >15 letters. Long-term VA developments in DME and RVO were more favourable with 81% of DME and 79% of patients with RVO gaining or maintaining vision at 5 years. In AMD, median injection frequency was six in year 1 and between four and five in consecutive years. In DME and RVO, median injection frequency was six in year 1 but lower compared with AMD in consecutive years. Injection frequency in DME was weakly associated with patient age (rs=0.1; p=0.03). Conclusions In AMD, the initial VA gain was not maintained long term despite higher injection numbers compared with DME, RVO and myopic CNV. The presented real-world data provide a peer-group-based estimate of VA developments and injection frequencies for counselling patients undergoing long-term anti-VEGF therapy. PMID:27215744

  8. Letter Position Dyslexia in Arabic: From Form to Position

    PubMed Central

    Friedmann, Naama; Haddad-Hanna, Manar

    2012-01-01

    This study reports the reading of 11 Arabic-speaking individuals with letter position dyslexia (LPD), and the effect of letter form on their reading errors. LPD is a peripheral dyslexia caused by a selective deficit to letter position encoding in the orthographic-visual analyzer, which results in migration of letters within words, primarily of middle letters. The Arabic orthography is especially interesting for the study of LPD because Arabic letters have different forms in different positions in the word. As a result, some letter position errors require letter form change. We compared the rate of letter migrations that change letter form with migrations that do not change letter form in 10 Arabic-speaking individuals with developmental LPD, and one bilingual Arabic and Hebrew-speaking individual with acquired LPD. The results indicated that the participants made 40% letter position errors in migratable words when the resulting word included the letters in the same form, whereas migrations that changed letter form almost never occurred. The error rate of the Arabic-Hebrew bilingual reader was smaller in Arabic than in Hebrew. However, when only words in which migrations do not change letter form were counted, the rate was similar in Arabic and Hebrew. Hence, whereas orthographies with multiple letter forms for each letter might seem more difficult in some respects, these orthographies are in fact easier to read in some forms of dyslexia. Thus, the diagnosis of LPD in Arabic should consider the effect of letter forms on migration errors, and use only migratable words that do not require letter-form change. The theoretical implications for the reading model are that letter form (of the position-dependent type found in Arabic) is part of the information encoded in the abstract letter identity, and thus affects further word recognition processes, and that there might be a pre-lexical graphemic buffer in which the checking of orthographic well-formedness takes place

  9. Using Letters to Support Consultative Work in Schools

    ERIC Educational Resources Information Center

    Bozic, Nick

    2004-01-01

    This paper reports how consultative work with teachers can be supported by the use of letters. Letters were written by an educational psychologist (EP) after a consultation meeting with a teacher. Features of therapeutic letter writing and solution-focused brief therapy were used to increase the collaborative intent of the letters. Follow-up…

  10. 33 CFR 127.009 - Letter of recommendation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Letter of recommendation. 127.009... General § 127.009 Letter of recommendation. (a) After the COTP receives the Letter of Intent under § 127.007(a) or (b), the COTP issues a Letter of Recommendation (LOR) as to the suitability of the...

  11. Representation of Letter Position in Spelling: Evidence from Acquired Dysgraphia

    ERIC Educational Resources Information Center

    Fischer-Baum, Simon; McCloskey, Michael; Rapp, Brenda

    2010-01-01

    The graphemic representations that underlie spelling performance must encode not only the identities of the letters in a word, but also the positions of the letters. This study investigates how letter position information is represented. We present evidence from two dysgraphic individuals, CM and LSS, who perseverate letters when spelling: that…

  12. 19 CFR 177.9 - Effect of ruling letters.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Effect of ruling letters. 177.9 Section 177.9... TREASURY (CONTINUED) ADMINISTRATIVE RULINGS General Ruling Procedure § 177.9 Effect of ruling letters. (a) Effect of ruling letters generally. A ruling letter issued by the Customs Service under the provisions...

  13. 48 CFR 1602.170-10 - Letter of credit.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Letter of credit. 1602.170... Terms 1602.170-10 Letter of credit. Letter of credit means the method by which certain carriers, and... available. For each carrier participating in the letter of credit arrangement for payment under this...

  14. 12 CFR 337.2 - Standby letters of credit.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Standby letters of credit. 337.2 Section 337.2... UNSAFE AND UNSOUND BANKING PRACTICES § 337.2 Standby letters of credit. (a) Definition. As used in this section, the term standby letter of credit means any letter of credit, or similar arrangement...

  15. 12 CFR 337.2 - Standby letters of credit.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Standby letters of credit. 337.2 Section 337.2... UNSAFE AND UNSOUND BANKING PRACTICES § 337.2 Standby letters of credit. (a) Definition. As used in this section, the term standby letter of credit means any letter of credit, or similar arrangement...

  16. Models of Discourse in the Letter of Complaint

    ERIC Educational Resources Information Center

    Hartford, Beverly; Mahboob, Ahmar

    2004-01-01

    In both the Outer Circle and the Expanding Circle countries, books which provide examples of letters written in English and guidelines for writing these letters are available for students, business people, and any others who have an interest or need for writing such letters. These model letters are not only for business correspondence, but also…

  17. Letter Writing: A Great Way to Explore Whole Language.

    ERIC Educational Resources Information Center

    Flack, Jerry

    1995-01-01

    Discusses the importance of using letter writing to promote whole-language learning. Suggests ideas and actions, and provides examples of children's literature that uses the letter format, to weave letters and letter writing into the whole-language curriculum. (BAC)

  18. Neural Correlates of Top-Down Letter Processing

    ERIC Educational Resources Information Center

    Liu, Jiangang; Li, Jun; Zhang, Hongchuan; Rieth, Cory A.; Huber, David E.; Li, Wu; Lee, Kang; Tian, Jie

    2010-01-01

    This fMRI study investigated top-down letter processing with an illusory letter detection task. Participants responded whether one of a number of different possible letters was present in a very noisy image. After initial training that became increasingly difficult, they continued to detect letters even though the images consisted of pure noise,…

  19. 19 CFR 177.9 - Effect of ruling letters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Effect of ruling letters. 177.9 Section 177.9... TREASURY (CONTINUED) ADMINISTRATIVE RULINGS General Ruling Procedure § 177.9 Effect of ruling letters. (a) Effect of ruling letters generally. A ruling letter issued by the Customs Service under the provisions...

  20. The strong connection between sensory and cognitive performance in old age: not due to sensory acuity reductions operating during cognitive assessment.

    PubMed

    Lindenberger, U; Scherer, H; Baltes, P B

    2001-06-01

    Cognitive aging research has documented a strong increase in the covariation between sensory and cognitive functioning with advancing age. In part, this finding may reflect sensory acuity reductions operating during cognitive assessment. To examine this possibility, the authors administered cognitive tasks used in prior studies (e.g., Lindenberger & Baltes, 1994) to middle-aged adults under age-simulation conditions of reduced visual acuity, auditory acuity, or both. Visual acuity was lowered through partial occlusion filters, and auditory acuity through headphone-shaped noise protectors. Acuity manipulations reduced visual acuity and auditory acuity in the speech range to values reaching or approximating old-age acuity levels, respectively, but did not lower cognitive performance relative to control conditions. Results speak against assessment-related sensory acuity accounts of the age-related increase in the connection between sensory and cognitive functioning and underscore the need to explore alternative explanations, including a focus on general aspects of brain aging.

  1. Bevacizumab injection in patients with age-related macular degeneration associated with poor initial visual acuity.

    PubMed

    El Matri, Leila; Bouraoui, Rym; Chebil, Ahmed; Kort, Fedra; Bouladi, Mejda; Limaiem, Rym; Landoulsi, Hana

    2012-01-01

    Purpose. To evaluate functional and anatomic effects of intravitreal bevacizumab in patients with neovascular AMD and initial low visual acuity. Methods. Retrospective case series of 38 eyes with neovascular AMD and initial visual acuity of 20/200 or less, treated with intravitreal bevacizumab injection. Results. Mean followup was 14.1 months ±  7.1 (range: 5 to 24 months). Mean logMAR vision at baseline was 1.38 logMAR ±  0.33, at 6 months was 1.14 logMAR ±  0.37 (P = 0.001) and at 12 months was 1.22 logMar ±  0.33 (P = 0.004). Mean baseline central retinal thickness was 431 μm ±  159.7 at 6 months was 293.43 μm  ±  122.79 (P = 10(-4)) and at 12 months was 293.1 μm  ±  130 (P = 0.004). Visual acuity improved in both patients with or without prior PDT treatment. Conclusions. Intravitreal bevacizumab injection may increase the chance of visual acuity gain in neovascular AMD even in cases with initial low visual acuity.

  2. Dot Display Affects Approximate Number System Acuity and Relationships with Mathematical Achievement and Inhibitory Control

    PubMed Central

    Norris, Jade Eloise; Castronovo, Julie

    2016-01-01

    Much research has investigated the relationship between the Approximate Number System (ANS) and mathematical achievement, with continued debate surrounding the existence of such a link. The use of different stimulus displays may account for discrepancies in the findings. Indeed, closer scrutiny of the literature suggests that studies supporting a link between ANS acuity and mathematical achievement in adults have mostly measured the ANS using spatially intermixed displays (e.g. of blue and yellow dots), whereas those failing to replicate a link have primarily used spatially separated dot displays. The current study directly compared ANS acuity when using intermixed or separate dots, investigating how such methodological variation mediated the relationship between ANS acuity and mathematical achievement. ANS acuity was poorer and less reliable when measured with intermixed displays, with performance during both conditions related to inhibitory control. Crucially, mathematical achievement was significantly related to ANS accuracy difference (accuracy on congruent trials minus accuracy on incongruent trials) when measured with intermixed displays, but not with separate displays. The findings indicate that methodological variation affects ANS acuity outcomes, as well as the apparent relationship between the ANS and mathematical achievement. Moreover, the current study highlights the problem of low reliabilities of ANS measures. Further research is required to construct ANS measures with improved reliability, and to understand which processes may be responsible for the increased likelihood of finding a correlation between the ANS and mathematical achievement when using intermixed displays. PMID:27195749

  3. Transcranial direct current stimulation improves visual acuity in amblyopic Long-Evans rats.

    PubMed

    Castaño-Castaño, S; Garcia-Moll, A; Morales-Navas, M; Fernandez, E; Sanchez-Santed, F; Nieto-Escamez, F

    2017-02-15

    Transcranial direct current stimulation (tDCS) has proved to increase brain cortex plasticity and different models of brain damage. In this work, we have analyzed the effects of tDCS in an experimental model of amblyopia using Long-Evans rats. Animals were monocularly deprived between 12 and 75 postnatal days and visual cortex contralateral to the deprived eye was stimulated using anodal tDCS during 8days (20min/day). The effects of tDCS treatment on the visual function were evaluated by using the optomotor reflex of the animals as a measure of visual acuity. Results obtained indicate that monocular occlusion during the critical period lead to a reduction of visual acuity in monocular and binocular conditions. Stimulation with anodal tDCS produced a nearly full recovery in visual acuity of amblyopic animals. However, same stimulation protocol in healthy control animals produced a decrease of binocular visual acuity. These data indicate that tDCS can reverse the effects of monocular deprivation on visual acuity, although it is essential to use this technique in a controlled way due to the possible adverse effects on healthy individuals.

  4. Robot-Aided Mapping of Wrist Proprioceptive Acuity across a 3D Workspace

    PubMed Central

    Marini, Francesca; Squeri, Valentina; Morasso, Pietro; Konczak, Jürgen; Masia, Lorenzo

    2016-01-01

    Proprioceptive signals from peripheral mechanoreceptors form the basis for bodily perception and are known to be essential for motor control. However we still have an incomplete understanding of how proprioception differs between joints, whether it differs among the various degrees-of-freedom (DoFs) within a particular joint, and how such differences affect motor control and learning. We here introduce a robot-aided method to objectively measure proprioceptive function: specifically, we systematically mapped wrist proprioceptive acuity across the three DoFs of the wrist/hand complex with the aim to characterize the wrist position sense. Thirty healthy young adults performed an ipsilateral active joint position matching task with their dominant wrist using a haptic robotic exoskeleton. Our results indicate that the active wrist position sense acuity is anisotropic across the joint, with the abduction/adduction DoF having the highest acuity (the error of acuity for flexion/extension is 4.64 ± 0.24°; abduction/adduction: 3.68 ± 0.32°; supination/pronation: 5.15 ± 0.37°) and they also revealed that proprioceptive acuity decreases for smaller joint displacements. We believe this knowledge is imperative in a clinical scenario when assessing proprioceptive deficits and for understanding how such sensory deficits relate to observable motor impairments. PMID:27536882

  5. A comparison of the effects of ageing upon vernier and bisection acuity.

    PubMed

    Garcia-Suarez, Luis; Barrett, Brendan T; Pacey, Ian

    2004-05-01

    While most positional acuity tasks exhibit an age-related decline in performance, the effect of ageing upon vernier acuity continues to be the subject of some debate. In the present study we employed a stimulus design that enabled the simultaneous determination of bisection and vernier acuities in 36 subjects, aged between 22 and 84 years. This approach provided a means for directly testing the hypothesis that ageing affects bisection acuity but not vernier acuity by ensuring that differences in stimulus configuration and in the subject's task were kept to an absolute minimum. Optimum thresholds increased as a function of age for both bisection and vernier tasks. Inter-subject threshold variability also increased with age. Issues surrounding the comparison of absolute vernier thresholds across different studies are discussed and two important methodological factors are identified: the precise statistical method used to estimate thresholds, and the magnitude, in angular terms, of the smallest spatial offset of the elements of the vernier stimulus which can be displayed. Comparison with previously published data indicates that the discrepancy between this study and most previous investigations with respect to the effect of age upon vernier performance can be at least partly accounted for by differences in the minimum displayable vernier offset. Vernier thresholds do increase with age. The increased variability of vernier thresholds in older subjects would appear to limit the diagnostic value of the test as a means of enabling normal ageing to be distinguished from visual loss due to pathology of the eye or visual system.

  6. Relation between Approximate Number System Acuity and Mathematical Achievement: The Influence of Fluency

    PubMed Central

    Wang, Li; Sun, Yuhua; Zhou, Xinlin

    2016-01-01

    Previous studies have observed inconsistent relations between the acuity of the Approximate Number System (ANS) and mathematical achievement. In this paper, we hypothesize that the relation between ANS acuity and mathematical achievement is influenced by fluency; that is, the mathematical achievement test covering a greater expanse of mathematical fluency may better reflect the relation between ANS acuity and mathematics skills. We explored three types of mathematical achievement tests utilized in this study: Subtraction, graded, and semester-final examination. The subtraction test was designed to measure the mathematical fluency. The graded test was more fluency-based than the semester-final examination, but both involved the same mathematical knowledge from the class curriculum. A total of 219 fifth graders from primary schools were asked to perform all three tests, then given a numerosity comparison task, a visual form perception task (figure matching), and a series of other tasks to assess general cognitive processes (mental rotation, non-verbal matrix reasoning, and choice reaction time). The findings were consistent with our expectations. The relation between ANS acuity and mathematical achievement was particularly clearly reflected in the participants’ performance on the visual form perception task, which supports the domain-general explanations for the underlying mechanisms of the relation between ANS acuity and math achievement. PMID:28066291

  7. Relation between Approximate Number System Acuity and Mathematical Achievement: The Influence of Fluency.

    PubMed

    Wang, Li; Sun, Yuhua; Zhou, Xinlin

    2016-01-01

    Previous studies have observed inconsistent relations between the acuity of the Approximate Number System (ANS) and mathematical achievement. In this paper, we hypothesize that the relation between ANS acuity and mathematical achievement is influenced by fluency; that is, the mathematical achievement test covering a greater expanse of mathematical fluency may better reflect the relation between ANS acuity and mathematics skills. We explored three types of mathematical achievement tests utilized in this study: Subtraction, graded, and semester-final examination. The subtraction test was designed to measure the mathematical fluency. The graded test was more fluency-based than the semester-final examination, but both involved the same mathematical knowledge from the class curriculum. A total of 219 fifth graders from primary schools were asked to perform all three tests, then given a numerosity comparison task, a visual form perception task (figure matching), and a series of other tasks to assess general cognitive processes (mental rotation, non-verbal matrix reasoning, and choice reaction time). The findings were consistent with our expectations. The relation between ANS acuity and mathematical achievement was particularly clearly reflected in the participants' performance on the visual form perception task, which supports the domain-general explanations for the underlying mechanisms of the relation between ANS acuity and math achievement.

  8. Quantitative assessment of visual acuity in projective head-mounted displays

    NASA Astrophysics Data System (ADS)

    Fidopiastis, Cali M.; Meyer, Catherine; Fuhrman, Christopher A.; Rolland, Jannick P.

    2003-09-01

    One issue of head mounted display design relates to the tradeoff between field of view (FOV) and resolution, which can lead to reduced visual acuity (VA). Essentially, an increase in FOV causes a decrease in visual acuity, for a given LCD display that has a fixed number of pixels. The effects of enhanced brightness on VA using two different types of retro-reflective material (cubed or beaded) were tested using a 52 deg. FOV projective helmet mounted display with VGA resolution. Three lighting conditions were also tested. Based on the display size, resolution, and FOV, we estimated a maximum visual acuity of 4.1 minutes of arc. In a counter-balanced between measures design, subjects' psychometric acuity functions were determined using a computer-generated 4AFC Landolt C test presented stereoscopically and probit analysis. The results confirmed that the maximum visual acuity possible within the setup was 4.1 arc minutes, the limit imposed by the microdisplay, and not the retroreflective material.

  9. Determine the effect of neck muscle fatigue on dynamic visual acuity in healthy young adults

    PubMed Central

    Al Saif, Amer A.; Al Senany, Samira

    2015-01-01

    [Purpose] The aim of this study was to determine whether neck muscle fatigue affects dynamic visual acuity in healthy young participants. [Subjects and Methods] This study was a double-blinded, prospective, randomized, controlled trial. Thirty healthy young subjects (ages 21 to 30 years) participated in the study. Participants were randomly divided into an experimental group (n=15) and a control group (n=15). The experimental group performed an exercise designed to induce neck muscle fatigue and the control group preformed non-fatiguing sham exercises. [Results] There were significant differences in mean dynamic visual acuity between the two groups (0.26±0.11 LogMar versus 0.003±0.02 LogMar). Subjects in the experimental group showed a significant decline in their dynamic visual acuity compared with the control group. Dynamic visual acuity strongly correlated with neck muscle fatigue (r = 0.79). No significant differences in joint position error were observed between the two groups and no significant correlations between joint position error and neck muscle fatigue were observed (r = 0.23). [Conclusion] The results of this study suggest that neck muscle fatigue negatively impacts dynamic visual acuity. Although not statistically significant, cervical spine proprioception as measured by the joint position error in the experimental group was diminished after fatigue. PMID:25642087

  10. Determine the effect of neck muscle fatigue on dynamic visual acuity in healthy young adults.

    PubMed

    Al Saif, Amer A; Al Senany, Samira

    2015-01-01

    [Purpose] The aim of this study was to determine whether neck muscle fatigue affects dynamic visual acuity in healthy young participants. [Subjects and Methods] This study was a double-blinded, prospective, randomized, controlled trial. Thirty healthy young subjects (ages 21 to 30 years) participated in the study. Participants were randomly divided into an experimental group (n=15) and a control group (n=15). The experimental group performed an exercise designed to induce neck muscle fatigue and the control group preformed non-fatiguing sham exercises. [Results] There were significant differences in mean dynamic visual acuity between the two groups (0.26±0.11 LogMar versus 0.003±0.02 LogMar). Subjects in the experimental group showed a significant decline in their dynamic visual acuity compared with the control group. Dynamic visual acuity strongly correlated with neck muscle fatigue (r = 0.79). No significant differences in joint position error were observed between the two groups and no significant correlations between joint position error and neck muscle fatigue were observed (r = 0.23). [Conclusion] The results of this study suggest that neck muscle fatigue negatively impacts dynamic visual acuity. Although not statistically significant, cervical spine proprioception as measured by the joint position error in the experimental group was diminished after fatigue.

  11. Letter from President Millard Fillmore to the Emperor of Japan: The President's Letter Opened a Closed Country to the West

    ERIC Educational Resources Information Center

    Pinkert, Marvin; Potter, Lee Ann

    2004-01-01

    In 1852, Commodore Matthew C. Perry of the U.S. Navy sailed to Japan with instructions to deliver a letter from President Millard Fillmore to the Emperor. The letter eventually led to the 1854 Treaty of Kanagawa and the opening of Japan to trade with Western nations. The State Department's letter book copy of the letter is featured in this…

  12. Letter-Transposition Effects Are Not Universal: The Impact of Transposing Letters in Hebrew

    ERIC Educational Resources Information Center

    Velan, Hadas; Frost, Ram

    2009-01-01

    We examined the effects of letter-transposition in Hebrew in three masked-priming experiments. Hebrew, like English has an alphabetic orthography where sequential and contiguous letter strings represent phonemes. However, being a Semitic language it has a non-concatenated morphology that is based on root derivations. Experiment 1 showed that…

  13. ERP Correlates of Letter Identity and Letter Position Are Modulated by Lexical Frequency

    ERIC Educational Resources Information Center

    Vergara-Martinez, Marta; Perea, Manuel; Gomez, Pablo; Swaab, Tamara Y.

    2013-01-01

    The encoding of letter position is a key aspect in all recently proposed models of visual-word recognition. We analyzed the impact of lexical frequency on letter position assignment by examining the temporal dynamics of lexical activation induced by pseudowords extracted from words of different frequencies. For each word (e.g., BRIDGE), we created…

  14. The Apgar Score.

    PubMed

    2015-10-01

    The Apgar score provides an accepted and convenient method for reporting the status of the newborn infant immediately after birth and the response to resuscitation if needed. The Apgar score alone cannot be considered as evidence of, or a consequence of, asphyxia; does not predict individual neonatal mortality or neurologic outcome; and should not be used for that purpose. An Apgar score assigned during resuscitation is not equivalent to a score assigned to a spontaneously breathing infant. The American Academy of Pediatrics and the American College of Obstetricians and Gynecologists encourage use of an expanded Apgar score reporting form that accounts for concurrent resuscitative interventions.

  15. Acquisition of the Cardinal Principle Coincides with Improvement in Approximate Number System Acuity in Preschoolers

    PubMed Central

    Shusterman, Anna; Slusser, Emily; Halberda, Justin; Odic, Darko

    2016-01-01

    Human mathematical abilities comprise both learned, symbolic representations of number and unlearned, non-symbolic evolutionarily primitive cognitive systems for representing quantities. However, the mechanisms by which our symbolic (verbal) number system becomes integrated with the non-symbolic (non-verbal) representations of approximate magnitude (supported by the Approximate Number System, or ANS) are not well understood. To explore this connection, forty-six children participated in a 6-month longitudinal study assessing verbal number knowledge and non-verbal numerical acuity. Cross-sectional analyses revealed a strong relationship between verbal number knowledge and ANS acuity. Longitudinal analyses suggested that increases in ANS acuity were most strongly related to the acquisition of the cardinal principle, but not to other milestones of verbal number acquisition. These findings suggest that experience with culture and language is intimately linked to changes in the properties of a core cognitive system. PMID:27078257

  16. The role of numeracy and approximate number system acuity in predicting value and probability distortion.

    PubMed

    Patalano, Andrea L; Saltiel, Jason R; Machlin, Laura; Barth, Hilary

    2015-12-01

    It is well documented that individuals distort outcome values and probabilities when making choices from descriptions, and there is evidence of systematic individual differences in distortion. In the present study, we investigated the relationship between individual differences in such distortions and two measures of numerical competence, numeracy and approximate number system (ANS) acuity. Participants indicated certainty equivalents for a series of simple monetary gambles, and data were used to estimate individual-level value and probability distortion, using a cumulative prospect theory framework. We found moderately strong negative correlations between numeracy and value and probability distortion, but only weak and non-statistically reliable correlations between ANS acuity and distortions. We conclude that low numeracy contributes to number distortion in decision making, but that approximate number system acuity might not underlie this relationship.

  17. Compared optical performances of multifocal and monofocal intraocular lenses (contrast sensitivity and dynamic visual acuity)

    PubMed Central

    Williamson, W; Poirier, L; Coulon, P; Verin, P

    1994-01-01

    The functional results (contrast sensitivity and dynamic visual acuity) of 19 multifocal (3M design) and 14 all polymethylmethacrylate biconvex monofocal intraocular lenses (IOLs), 6 mm in optical diameter were compared. Best corrected visual acuity was > or = 8/10 (Monoyer chart) Parinaud 2 in all cases. Major differences of functional performance in favour of monofocal IOLs were found outside standard conditions of vision (low contrast and illumination levels). A significant difference in contrast sensitivity was found for each spatial frequency in favour of multifocal IOLs (0.0016 < p < 0.05). Mesopic vision was statistically higher in the monofocal IOL group (p = 0.0015). Moreover, dynamic visual acuity allowed accurate evaluation of the difference in performance between these two models of implant. In view of these results multifocal IOLs should be reserved for patients with normal psychosensitive adaptation; an ocular pathology that could alter contrast sensitivity or mesopic vision is a contraindication for multifocal IOLs. PMID:8199107

  18. Sensorimotor posture control in the blind: superior ankle proprioceptive acuity does not compensate for vision loss.

    PubMed

    Ozdemir, Recep A; Pourmoghaddam, Amir; Paloski, William H

    2013-09-01

    To better understand sensorimotor posture control differences between blind and sighted individuals, we examined the role of ankle joint proprioception and ankle muscle strength on postural control in healthy blind (n=13, 25-58 years) and age- and sex-matched sighted (n=15, 20-65 years) volunteers. We measured ankle joint proprioceptive acuity and isokinetic muscle strength in plantarflexion and dorsiflexion using an isokinetic dynamometer. We also assessed postural control performance during quiet bipedal stance with and without sudden postural perturbations, and during quiet unipedal stance. We found that while our blind subjects exhibited significantly better proprioceptive acuity than our sighted subjects their postural control performance was significantly poorer than that of the sighted group with eyes open, and no different from that of the sighted group with eyes closed suggesting that their superior proprioceptive acuity does not translate to improved balance control.

  19. The effects of time, luminance, and high contrast targets: revisiting grating acuity in the domestic cat.

    PubMed

    Clark, Daria L; Clark, Robert A

    2013-11-01

    Based on optical clarity and retinal cone density, the cat has a potential acuity of 20-30 cycles per degree (cpd), yet most behavioral studies estimate feline acuity between 3 and 9 cpd. Those studies, however, were limited by restrictive experimental conditions that may have inadvertently lowered the estimated grating acuity. Two domestic cats previously trained on a two-choice visual discrimination task were retrained on a grating detection/discrimination task with unlimited time, high luminance, high contrast targets, and adequate space to prevent poor accommodation from affecting the results. Initially, vertical gratings of increasing cpd were tested until failure. Then, horizontal gratings of increasing cpd were tested until failure. Finally, the finest horizontal grating resolved was confirmed with a third test requiring 24 correct out of 36 consecutive trials, yielding a binomial probability less than 0.02 of non-random occurrence. M1, a 7-year-old male gray tabby with +2.00 OU refraction, tested for a grating detection acuity of 15 cpd for both vertical and horizontal gratings (binomial probability = 0.009). F1, a 2-year-old female gray tabby with +0.25 OU refraction, tested for a grating orientation discrimination acuity of 20 cpd for both vertical and horizontal gratings (binomial probability = 0.004). These results demonstrate that a young cat with good focus is capable of discriminating 20 cpd, in close agreement with the physiologic maximum. Uncorrected focusing errors appear to degrade visual performance. Optimum experimental conditions resulted in better grating acuity measurements than previously reported, emphasizing the importance of environmental factors in feline behavioral testing.

  20. Characteristics of Fixational Eye Movements in Amblyopia: Limitations on Fixation Stability and Acuity?

    PubMed Central

    Kumar, Girish; Li, Roger W.; Levi, Dennis M.

    2015-01-01

    Persons with amblyopia, especially those with strabismus, are known to exhibit abnormal fixational eye movements. In this paper, we compared six characteristics of fixational eye movements among normal control eyes (n=16), the non-amblyopic fellow eyes and the amblyopic eyes of anisometropic (n=14) and strabismic amblyopes (n=14). These characteristics include the frequency, magnitude of landing errors, amplitude and speed of microsaccades, and the amplitude and speed of slow drifts. Fixational eye movements were recorded using retinal imaging while observers monocularly fixated a 1° cross. Eye position data were recovered using a cross-correlation procedure. We found that in general, the characteristics of fixational eye movements are not significantly different between the fellow eyes of amblyopes and controls, and that the strabismic amblyopic eyes are always different from the other groups. Next, we determined the primary factors that limit fixation stability and visual acuity in amblyopic eyes by examining the relative importance of the different oculomotor characteristics, adding acuity (for fixation stability) or fixation stability (for acuity), and the type of amblyopia, as predictive factors in a multiple linear regression model. We show for the first time that the error magnitude of microsaccades, acuity, amplitude and frequency of microsaccades are primary factors limiting fixation stability; while the error magnitude, fixation stability, amplitude of drifts and amplitude of microsaccades are the primary factors limiting acuity. A mediation analysis showed that the effects of error magnitude and amplitude of microsaccades on acuity could be explained, at least in part, by their effects on fixation stability. PMID:25668775

  1. Vestibular, Visual Acuity and Balance Outcomes in Children with Cochlear Implants: A Preliminary Report

    PubMed Central

    Janky, Kristen; Givens, Diane

    2016-01-01

    There is a high incidence of vestibular loss in children with cochlear implants (CCI). However, the relationship between vestibular loss and various outcomes is unknown in children. Objectives 1) determine if age-related changes in peripheral vestibular tests occur; 2) quantify peripheral vestibular function in children with normal hearing (CNH) and CCI; 3) determine if amount of vestibular loss predicts visual acuity and balance performance. Design Eleven CCI and 12 CNH completed the following tests of vestibular function: ocular and cervical vestibular evoked myogenic potential (VEMP) to assess utricle and saccule function, and the video head impulse test (vHIT) to assess semicircular canal function. The relationship between amount of vestibular loss and the following balance and visual acuity outcomes was assessed: dynamic gait index, single leg stance, the sensory organization test, and tests of visual acuity, including dynamic visual acuity and the gaze stabilization test. Results 1) There were no significant age-related changes in peripheral vestibular testing with the exception of the n23 cervical VEMP latency, which was moderately correlated with age; 2) CCI had significantly higher rates of vestibular loss for each test of canal and otolith function; 3) Amount of vestibular loss predicted performance on single leg stance, the dynamic gait index, some conditions of the sensory organization test, and the dynamic visual acuity test. Age was also a contributing factor for predicting the performance of almost all outcomes. Conclusions Preliminarily, children with vestibular loss do not recover naturally to levels of their healthy peers, particularly with activities that utilize vestibular input; they have poorer visual acuity and balance function. PMID:26182202

  2. Automatic letters with Microsoft Word for Windows.

    PubMed

    Gerraty, B J

    1996-03-01

    This article offers a simple process for creating a series of separate letter formats and then automating the production of individual letters from them. These letter formats can then be assembled into various categories and displayed on a computer screen. The key concepts are: Templates, Fields, Auto Macros, Macros and Custom Dialog Boxes. This is made possible because Word for Windows allows the exploration and alteration of its basic editing commands. It has great flexibility as nothing is set in concrete: a built-in command macro may be changed and a custom macro created to replace it. This article assumes the use of Microsoft Word 6.0 and some familiarity with it. The various macros notated are 'syntax sensitive' so a full stop or comma in the wrong place, or left out, will result in the macro failing to run.

  3. Tactile acuity training for patients with chronic low back pain: a pilot randomised controlled trial

    PubMed Central

    2014-01-01

    Background Chronic pain can disrupt the cortical representation of a painful body part. This disruption may play a role in maintaining the individual’s pain. Tactile acuity training has been used to normalise cortical representation and reduce pain in certain pain conditions. However, there is little evidence for the effectiveness of this intervention for chronic low back pain (CLBP). The primary aim of this study was to inform the development of a fully powered randomised controlled trial (RCT) by providing preliminary data on the effect of tactile acuity training on pain and function in individuals with CLBP. The secondary aim was to obtain qualitative feedback about the intervention. Methods In this mixed-methods pilot RCT 15 individuals were randomised to either an intervention (tactile acuity training) or a placebo group (sham tactile acuity training). All participants received 3 sessions of acuity training (intervention or sham) from a physiotherapist and were requested to undertake daily acuity home training facilitated by an informal carer (friend/relative). All participants also received usual care physiotherapy. The primary outcome measures were pain (0-100visual analogue scale (VAS)) and function (Roland Morris Disability Questionnaire (RMDQ)). Participants and their informal carers were invited to a focus group to provide feedback on the intervention. Results The placebo group improved by the greatest magnitude for both outcome measures, but there was no statistically significant difference (Mean difference (95%CI), p-value) between groups for change in pain (25.6 (-0.7 to 51.9), p = 0.056) or function (2.2 (-1.6 to 6.0), p = 0.237). Comparing the number of individuals achieving a minimally clinically significant improvement, the placebo group had better outcomes for pain with all participants achieving ≥30% improvement compared to only a third of the intervention group (6/6 vs. 3/9, p = 0.036). Qualitatively, participants reported that

  4. Posterior staphyloma in oculocutaneous albinism: another possible cause of reduced visual acuity.

    PubMed

    Lee, Susan; Schimmenti, Lisa A; King, Richard A; Brilliant, Murray; Anderson, Jennifer L; Schoonveld, Cheri; Summers, C Gail

    2015-12-01

    Posterior staphyloma is typically associated with myopic degeneration and has not been recognized as a cause of reduced visual acuity in albinism. We report 3 cases of posterior staphyloma, each with oculocutaneous albinism (OCA) defined by phenotype and genotype. Two cases are biological sisters with OCA type 2; one was myopic and the other was hyperopic. The third case involves a man with OCA associated with Hermansky-Pudlak syndrome (HPS-5). Staphyloma may be another cause of reduced visual acuity in albinism, particularly with increasing age. It may occur in association with myopia or hyperopia.

  5. [Structured electronic consultation letter for shoulder disorders].

    PubMed

    Paloneva, Juha; Oikari, Marjo; Ylinen, Jari; Ingalsuo, Minna; Ilkka, Kunnamo; Ilkka, Kiviranta

    2012-01-01

    Referral to a specialist has a significant influence on management of the patient and costs associated with the treatments. However, development and research of the process by which patients are referred has been almost neglected. Expectations considering the purpose, contents, and timing of the referral of the consulting physician and the consultant do not always meet. A structured, electronic consultation letter was developed to respond this need. Functionality and interactivity are the key elements of the referral, including (1) an electronic referral letter to a specialist, (2) interactive education in clinical examination and management of shoulder disorders, and (3) an instrument of clinical examination and documentation of shoulder disorders.

  6. Representation of Letter Position in Spelling: Evidence from Acquired Dysgraphia

    PubMed Central

    Fischer-Baum, Simon; McCloskey, Michael; Rapp, Brenda

    2010-01-01

    The graphemic representations that underlie spelling performance must encode not only the identities of the letters in a word, but also the positions of the letters. This study investigates how letter position information is represented. We present evidence from two dysgraphic individuals, CM and LSS, who perseverate letters when spelling: that is, letters from previous spelling responses intrude into subsequent responses. The perseverated letters appear more often than expected by chance in the same position in the previous and subsequent responses. We used these errors to address the question of how letter position is represented in spelling. In a series of analyses we determined how often the perseveration errors produced maintain position as defined by a number of alternative theories of letter position encoding proposed in the literature. The analyses provide strong evidence that the grapheme representations used in spelling encode letter position such that position is represented in a graded manner based on distance from both edges of the word. PMID:20378104

  7. Letters in the forest: global precedence effect disappears for letters but not for non-letters under reading-like conditions

    PubMed Central

    Lachmann, Thomas; Schmitt, Andreas; Braet, Wouter; van Leeuwen, Cees

    2014-01-01

    Normally skilled reading involves special processing strategies for letters, which are habitually funneled into an abstract letter code. On the basis of previous studies we argue that this habit leads to the preferred usage of an analytic strategy for the processing of letters, while non-letters are preferably processed via a holistic strategy. The well-known global precedence effect (GPE) seems to contradict to this assumption, since, with compound, hierarchical figures, including letter items, faster responses are observed to the global than to the local level of the figure, as well as an asymmetric interference effect from global to local level. We argue that with letters these effects depend on presentation conditions; only when they elicit the processing strategies automatized for reading, an analytic strategy for letters in contrast to non-letters is to be expected. We compared the GPE for letters and non-letters in central viewing, with the global stimulus size close to the functional visual field in whole word reading (6.5° of visual angle) and local stimuli close to the critical size for fluent reading of individual letters (0.5° of visual angle). Under these conditions, the GPE remained robust for non-letters. For letters, however, it disappeared: letters showed no overall response time advantage for the global level and symmetric congruence effects (local-to-global as well as global-to-local interference). We interpret these results as according to the view that reading is based on resident analytic visual processing strategies for letters. PMID:25101012

  8. Letters in the forest: global precedence effect disappears for letters but not for non-letters under reading-like conditions.

    PubMed

    Lachmann, Thomas; Schmitt, Andreas; Braet, Wouter; van Leeuwen, Cees

    2014-01-01

    Normally skilled reading involves special processing strategies for letters, which are habitually funneled into an abstract letter code. On the basis of previous studies we argue that this habit leads to the preferred usage of an analytic strategy for the processing of letters, while non-letters are preferably processed via a holistic strategy. The well-known global precedence effect (GPE) seems to contradict to this assumption, since, with compound, hierarchical figures, including letter items, faster responses are observed to the global than to the local level of the figure, as well as an asymmetric interference effect from global to local level. We argue that with letters these effects depend on presentation conditions; only when they elicit the processing strategies automatized for reading, an analytic strategy for letters in contrast to non-letters is to be expected. We compared the GPE for letters and non-letters in central viewing, with the global stimulus size close to the functional visual field in whole word reading (6.5° of visual angle) and local stimuli close to the critical size for fluent reading of individual letters (0.5° of visual angle). Under these conditions, the GPE remained robust for non-letters. For letters, however, it disappeared: letters showed no overall response time advantage for the global level and symmetric congruence effects (local-to-global as well as global-to-local interference). We interpret these results as according to the view that reading is based on resident analytic visual processing strategies for letters.

  9. Introduction to Literary Criticism: "The Scarlet Letter."

    ERIC Educational Resources Information Center

    Lawrence, Lisa

    This course seeks to provide high school students the opportunity to sharpen their critical thinking skills and use of language through acquaintance with some ideas of literary criticism. The course features Nathaniel Hawthorne's "The Scarlet Letter," assuming that the students have just finished reading that American classic novel. The…

  10. Elevation Withdrawal Letter - signed March 27, 2003

    EPA Pesticide Factsheets

    A letter regarding a recent decision to issue a Clean Water Act Section 404 permit to the Virginia Seafood Council for the trial placement of one million non-native oysters into waters of the Chesapeake Bay and the Atlantic Ocean.

  11. Letters of a Slave Turned Union Soldier.

    ERIC Educational Resources Information Center

    Humanities, 1990

    1990-01-01

    Discusses the influx of Black soldiers into the Union army following the Emancipation Proclamation. Concentrates on the case of Private Spotswood Rice. Provides a short history of Rice, including copies of Rice's letters to his enslaved daughters, the daughter's slaveholders, and an angry retort from the slaveowner to the federal commander in…

  12. Letters from Roger: Exercises in Communication.

    ERIC Educational Resources Information Center

    Campbell, Russell N.; Bracy, Maryruth

    This book is designed for low-intermediate to advanced students of English as a second language. It provides a look at the world that awaits the foreign student who is to be suddenly immersed in an English-speaking society. The format involves a number of letters written by an American university student to a foreign student planning a trip to the…

  13. Resource Letter CF-1: Casimir Force

    SciTech Connect

    Lamoreaux, S.K.

    1999-10-01

    This resource letter provides an introductory guide to the literature on the Casimir force. Journal articles and books are cited for the following topics: introductory articles and books, calculations, dynamical Casimir effect, mechanical analogs, applications, and experiments. {copyright} {ital 1999 American Association of Physics Teachers.}

  14. 19 CFR 356.16 - Charging letter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Charging letter. 356.16 Section 356.16 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE PROCEDURES AND RULES FOR IMPLEMENTING ARTICLE 1904 OF THE NORTH AMERICAN FREE TRADE AGREEMENT Violation of a Protective Order or a...

  15. 19 CFR 356.16 - Charging letter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 3 2013-04-01 2013-04-01 false Charging letter. 356.16 Section 356.16 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE PROCEDURES AND RULES FOR IMPLEMENTING ARTICLE 1904 OF THE NORTH AMERICAN FREE TRADE AGREEMENT Violation of a Protective Order or a...

  16. 19 CFR 356.16 - Charging letter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Charging letter. 356.16 Section 356.16 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE PROCEDURES AND RULES FOR IMPLEMENTING ARTICLE 1904 OF THE NORTH AMERICAN FREE TRADE AGREEMENT Violation of a Protective Order or a...

  17. Samuel Beckett: Color, Letter, and Line.

    ERIC Educational Resources Information Center

    Conley, Tom

    1985-01-01

    Through a bilingual reading of Beckett's "Mal vu mal dit," the illusion of painted relief for printed letters is created. Colors manifest themselves through the continual process of translation. The French translation adds color to the black and white English text. (DF)

  18. 42 CFR 93.202 - Charge letter.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Charge letter. 93.202 Section 93.202 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES HEALTH ASSESSMENTS AND HEALTH EFFECTS STUDIES OF HAZARDOUS SUBSTANCES RELEASES AND FACILITIES PUBLIC HEALTH SERVICE POLICIES ON...

  19. "Physical Review Letters" in the Classroom

    ERIC Educational Resources Information Center

    Angiolillo, Paul J.; Lynch, Jonathan

    2010-01-01

    Ask any physicist what the preeminent journal in the field is, and I think the almost unanimous answer will be "Physical Review Letters" ("PRL"). This weekly journal of the American Physical Society publishes high-impact research from all the major subdisciplines of physics. This journal is not the one you would think is the first place a high…

  20. Employer Preferences for Resumes and Cover Letters

    ERIC Educational Resources Information Center

    Schullery, Nancy M.; Ickes, Linda; Schullery, Stephen E.

    2009-01-01

    This article reports the results of a survey of employers' preferences for resume style, resume delivery method, and cover letters. Employers still widely prefer the standard chronological resume, with only 3% desiring a scannable resume. The vast majority of employers prefer electronic delivery, either by email (46%) or at the company's Web site…

  1. 19 CFR 207.103 - Charging letter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 3 2013-04-01 2013-04-01 false Charging letter. 207.103 Section 207.103 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF WHETHER INJURY TO DOMESTIC INDUSTRIES RESULTS FROM IMPORTS SOLD AT LESS THAN FAIR VALUE OR FROM...

  2. 19 CFR 207.103 - Charging letter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Charging letter. 207.103 Section 207.103 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF WHETHER INJURY TO DOMESTIC INDUSTRIES RESULTS FROM IMPORTS SOLD AT LESS THAN FAIR VALUE OR FROM...

  3. 19 CFR 207.103 - Charging letter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 3 2012-04-01 2012-04-01 false Charging letter. 207.103 Section 207.103 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF WHETHER INJURY TO DOMESTIC INDUSTRIES RESULTS FROM IMPORTS SOLD AT LESS THAN FAIR VALUE OR FROM...

  4. 19 CFR 207.103 - Charging letter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Charging letter. 207.103 Section 207.103 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF WHETHER INJURY TO DOMESTIC INDUSTRIES RESULTS FROM IMPORTS SOLD AT LESS THAN FAIR VALUE OR FROM...

  5. 19 CFR 207.103 - Charging letter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 3 2014-04-01 2014-04-01 false Charging letter. 207.103 Section 207.103 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION NONADJUDICATIVE INVESTIGATIONS INVESTIGATIONS OF WHETHER INJURY TO DOMESTIC INDUSTRIES RESULTS FROM IMPORTS SOLD AT LESS THAN FAIR VALUE OR FROM...

  6. Copies of clinic letters to the family.

    PubMed

    Bartle, D G; Diskin, L; Finlay, F

    2004-11-01

    In April 2004 guidelines were introduced advising that letters to the GP should be copied to parents of young people. A study was carried out to ascertain the views of young people and their parents as to who they felt should receive correspondence after an outpatient appointment.

  7. Crowding Affects Letters and Symbols Differently

    ERIC Educational Resources Information Center

    Grainger, Jonathan; Tydgat, Ilse; Issele, Joanna

    2010-01-01

    Five experiments examined crowding effects with letter and symbol stimuli. Experiments 1 through 3 compared 2-alternative forced-choice (2AFC) identification accuracy for isolated targets presented left and right of fixation with targets flanked either by 2 other items of the same category or a single item situated to the right or left of targets.…

  8. Suspending Damage: A Letter to Communities

    ERIC Educational Resources Information Center

    Tuck, Eve

    2009-01-01

    In this open letter, Eve Tuck calls on communities, researchers, and educators to reconsider the long-term impact of "damage-centered" research--research that intends to document peoples' pain and brokenness to hold those in power accountable for their oppression. This kind of research operates with a flawed theory of change: it is often used to…

  9. Dear Teachers: Letters to Another Hero.

    ERIC Educational Resources Information Center

    Voices from the Middle, 2001

    2001-01-01

    Presents 54 thank you letters written by authors (of children's literature, young adult literature, and professional texts) to classroom teachers, from the shadow of the events of September 11th, 2001, offering their thanks for teachers' efforts to face those events with children, offering their personal thoughts about the events, or their…

  10. Suggestopaedia-Canada. Information Letter, No. 4.

    ERIC Educational Resources Information Center

    Racle, Gabriel

    This issue of the information letter consists of two articles, "Music Therapy" and "Research and Applications of Psychomusical Techniques"; a review of the book, "La musicotherapie et les methods nouvelles d'association des techniques" by Guilhot and Cecourt, and a bibliography of books on music therapy written in…

  11. Resource letter ETC-1 - Extraterrestrial civilization

    NASA Technical Reports Server (NTRS)

    Kuiper, Thomas B. H.; Brin, Glen David

    1989-01-01

    This resource letter provides a guide to the literature about intelligent life beyond the human sphere of exploration. It offers a starting point for professionals and academics interested in participating in the debate about the existence of other technological civilizations or in SETI. It can also serve as a reference for teaching. Several extensive bibliographies are cited.

  12. Writing Recommendation Letters--Without the Stress

    ERIC Educational Resources Information Center

    Toglia, Thomas V.

    2004-01-01

    Sooner or later, every educator hears the following plea from a current or former student: "Will you write a letter of recommendation for me?" Usually, the student is seeking employment or applying to a college or university for additional education. Many times instructors--taken off guard and unprepared for these requests--find themselves staring…

  13. Readerly and Writerly "Letters from the Park."

    ERIC Educational Resources Information Center

    Conde, Susana

    1993-01-01

    Discusses in depth the film "Cartas del parque" ("Letters from the Park"), the first of six films in the "Amores Dificiles" series. Notes that the film is pervaded by the traditional overdetermination of gender roles. Suggests that an intrusive and authoritative narrator makes of this both a "readerly" and a…

  14. Sound Localization Acuity in Very Young Infants: An Observer-Based Testing Procedure.

    ERIC Educational Resources Information Center

    Morrongiello, Barbara A.; And Others

    1990-01-01

    Infants of 8-28 weeks were tested to determine the smallest sound shift off midline and along the horizontal axis that the infants could reliably discriminate. Results indicated localization acuity increased with age. Video records revealed numerous auditory orienting behaviors with methodological implications. (RH)

  15. Perceptual limit to display resolution of images as per visual acuity

    NASA Astrophysics Data System (ADS)

    Masaoka, Kenichiro; Niida, Takahiro; Murakami, Miya; Suzuki, Kenji; Sugawara, Masayuki; Nojiri, Yuji

    2008-02-01

    Achieving ultimate visual realness of natural images on a display requires high resolution, so that artifacts due to finite image resolution are undetectable. An image resolution of 30 cycles/degree (cpd) or one pixel/arc-minute is often used as the criterion for viewing conditions when assessing displayed image quality. It is reasoned that if the pixel size is smaller than the separable angle of normal vision (20/20), the pixel structure is invisible and doesn't negatively affect image quality. However, it is not clear whether 30 cpd resolution is adequate to prevent seeing artifacts, especially for observers with better than 20/20 vision. We conducted experiments to find the threshold resolution of natural images and its dependence on visual acuity. Three objects were used; each object was presented 60 times at 5 resolutions (19.5, 26, 39, 52, or 78 cpd) next to the same image at a resolution of 156 cpd. Forty-five observers with visual acuity of 20/20 or better were asked to make a forced-choice distinction between the image pair in regard to resolution. Each observer indicated which image of the pair appeared at a higher resolution. The results show that the mean resolution for 75% correct responses for each of the visual acuity groups increased from more than 30 cpd as visual acuity increased and reached a plateau at 40-50 cpd at -0.3 logMAR.

  16. Acuities for textures and gratings in kittens assessed by preferential looking.

    PubMed

    Wilkinson, F

    1995-06-01

    A forced-choice preferential looking paradigm, similar to that developed for human infants, was used to assess visual thresholds in kittens between 21 and 45 days of age. In agreement with the earlier work of Sireteanu [19,30], the technique was found to be successful for grating acuity measurement. Acuity for square wave gratings (vs. matched greys) increased from 0.12 cycles/degrees at 21 days to 1.6 cycles/degrees at 40 days of age. Comparable results were obtained at three viewing distances: 20, 40, and 60 cm, indicating that accommodation is not a limiting factor in spatial resolution over this range of distances. Kittens also showed preferences for texture arrays with strong oriented components and 'texture acuities' were found to be comparable to acuity for square wave gratings. A consistent orientation anisotropy favouring horizontal line elements was seen in very young kittens but disappeared by 5 weeks of age. Preferences for texture arrays composed of dots were much weaker and thresholds could not be determined in all cases. The results are discussed in the context of the Banks and Ginsberg [2] model of infant preferences.

  17. Teachers' Knowledge of the Relationship of Auditory Acuity and Hearing Impairment to Reading.

    ERIC Educational Resources Information Center

    Marshall, Evelyn Myrtle

    Teacher's knowledge of the relationship of auditory acuity and hearing impairment to reading was evaluated with 60 teachers and specialists (regular classroom primary and upper elementary teachers, reading teachers, teachers of the learning disabled, teachers of the hearing impaired, and speech and language pathologists). Ss were administered a…

  18. A Close Eye on the Eagle-Eyed Visual Acuity Hypothesis of Autism

    ERIC Educational Resources Information Center

    Bolte, Sven; Schlitt, Sabine; Gapp, Volker; Hainz, Daniela; Schirman, Shella; Poustka, Fritz; Weber, Bernhard; Freitag, Christine; Ciaramidaro, Angela; Walter, Henrik

    2012-01-01

    Autism spectrum disorders (ASD) have been associated with sensory hypersensitivity. A recent study reported visual acuity (VA) in ASD in the region reported for birds of prey. The validity of the results was subsequently doubted. This study examined VA in 34 individuals with ASD, 16 with schizophrenia (SCH), and 26 typically developing (TYP).…

  19. Short-term visual deprivation, tactile acuity, and haptic solid shape discrimination.

    PubMed

    Crabtree, Charles E; Norman, J Farley

    2014-01-01

    Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task - perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task - the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation.

  20. The Effects of Drift and Displacement Motion on Dynamic Visual Acuity

    ERIC Educational Resources Information Center

    Aznar-Casanova, J. Antonio; Quevedo, Lluisa; Sinnett, Scott

    2005-01-01

    Dynamic Visual Acuity (DVA) can be measured from two types of equivalently considered movement referred to as drifting-motion and displacement-motion. Displacement motion can be best described as the horizontal displacement of a stimulus, thus implying pursuit eye movements, and involves moving the stimulus from the fixation point of gaze towards…

  1. Burn Patient Acuity Demographics, Scar Contractures, and Rehabilitation Treatment Time Related to Patient Outcomes (ACT)

    DTIC Science & Technology

    2014-10-01

    Scar Contractures, and Rehabilitation Treatment Time Related to Patient Outcomes, conveniently referred to as the ACT for representing Acuity...acute and intermediate phases of burn rehabilitation through the collection of daily treatment information for analysis. In particular, the ACT is...primarily interested in investigating the influence that time spent receiving rehabilitation treatments has on patient outcomes as a reflection of

  2. Binocular Visual Acuity of Children: Demographic and Socioeconomic Characteristics - United States.

    ERIC Educational Resources Information Center

    National Center for Health Statistics (DHEW/PHS), Hyattsville, MD.

    Reported were estimates of the uncorrected binocular visual acuity levels of distance and near for children aged 6 to 11 years in the noninstitutional population of the United States in relation to their demographic and socioeconomic background. A sample of 7,119 children participated in the Health Examination Survey program of 1963-65. Findings…

  3. Binocular Coordination, Acuity, and Locomotion: Interacting with Objects in the Environment.

    ERIC Educational Resources Information Center

    Knowlton, Marie; Lee, Inkyung

    1995-01-01

    This article addresses issues of orientation and mobility for students with visual impairments, including the perception of motion, visual mechanisms of binocular coordination, perception of impending collision, and body movement to avoid collision. Emphasis is on the role of binocular coordination ability and acuity. These concepts were evaluated…

  4. Evaluation of vestibular and dynamic visual acuity in adults with congenital deafness.

    PubMed

    Nakajima, Yukinori; Kaga, Kimitaka; Takekoshi, Hideki; Sakuraba, Keisyoku

    2012-10-01

    This study compared vestibular and dynamic visual acuity in 19 adult athletes with deafness participating in Deaflympics to those of 25 young adults with normal hearing. Balance capability was evaluated using a one-leg standing test with eyes open and stabilometry. Caloric tests and vestibular evoked myogenic potential tests were conducted to test vestibular function. Visual function was evaluated using a dynamic visual acuity test. No significant difference was found between results of the one-leg standing test with eyes open and stabilometry with eyes open. Athletes with deafness performed better than normal hearing young adults with eyes closed. The caloric test indicated hypofunction of the lateral semicircular canal function in 5 of the 19 athletes with deafness. Balance-function tests showed normal results for both groups. The results for athletes with deafness on visual acuity were better than those of controls. Young Deaflympics athletes with deafness can adjust their balance function as well as or better than normal hearing young adults using dynamic visual acuity.

  5. Impacting patient outcomes through design: acuity adaptable care/universal room design.

    PubMed

    Brown, Katherine Kay; Gallant, Dennis

    2006-01-01

    To succeed in today's challenging healthcare environment, hospitals must examine their impact on customers--patients and families--staff and physicians. By using competitive facility design and incorporating evidence-based concepts such as the acuity adaptable care delivery model and the universal room, the hospital will realize an impact on patient satisfaction that will enhance market share, on physician satisfaction that will foster loyalty, and on staff satisfaction that will decrease turnover. At the same time, clinical outcomes such as a reduction in mortality and complications and efficiencies such as a reduction in length of stay and minimization of hospital costs through the elimination of transfers can be gained. The results achieved are dependent on the principles used in designing the patient room that should focus on maximizing patient safety and improving healing. This article will review key design elements that support the success of an acuity adaptable unit such as the use of a private room with zones dedicated to patients, families, and staff, healing environment, technology, and decentralized nursing stations that support the success of the acuity adaptable unit. Outcomes of institutions currently utilizing the acuity adaptable concept will be reviewed.

  6. Home Energy Score

    SciTech Connect

    2011-12-16

    The Home Energy Score allows a homeowner to compare her or his home's energy consumption to that of other homes, similar to a vehicle's mile-per-gallon rating. A home energy assessor will collect energy information during a brief home walk-through and then score that home on a scale of 1 to 10.

  7. Establishing Passing Scores.

    ERIC Educational Resources Information Center

    McLarty, Joyce R.

    The problem of establishing appropriate passing scores is one of evaluation rather than estimation and not amenable to exact solution. It must therefore be approached by (1) identifying criteria for judging the acceptability of the passing score, (2) collecting the data appropriate to assessing each relevant criterion, and (3) judging how well the…

  8. SCORE - A DESCRIPTION.

    ERIC Educational Resources Information Center

    SLACK, CHARLES W.

    REINFORCEMENT AND ROLE-REVERSAL TECHNIQUES ARE USED IN THE SCORE PROJECT, A LOW-COST PROGRAM OF DELINQUENCY PREVENTION FOR HARD-CORE TEENAGE STREET CORNER BOYS. COMMITTED TO THE BELIEF THAT THE BOYS HAVE THE POTENTIAL FOR ETHICAL BEHAVIOR, THE SCORE WORKER FOLLOWS B.F. SKINNER'S THEORY OF OPERANT CONDITIONING AND REINFORCES THE DELINQUENT'S GOOD…

  9. Depressive Styles and Social Acuity: Further Evidence for Distinct Interpersonal Correlates of Dependency and Self-Criticism.

    ERIC Educational Resources Information Center

    Aube, Jennifer; Whiffen, Valerie E.

    1996-01-01

    Examines whether dependency and self-criticism (personality types linked with depression) are related to social acuity. Uses 90 university students who completed 2 measures of social acuity. Finds that self-critical persons were significantly less accurate on both tasks, even when controlling for depressive symptomatology. Supports previous…

  10. Agreement in Scoring Preclinical Dental Procedures: Impact on Grades and Instructor-Related Determinants.

    PubMed

    AlHumaid, Jehan; Tantawi, Maha El; Al-Ansari, Asim A; Al-Harbi, Fahad A

    2016-05-01

    The aims of this study were to assess agreement among instructors in scoring preclinical dental procedures, the effect of this agreement on grades, and factors associated with agreement and grades differences. Twenty-six instructors from five clinical specialties participated in a scoring exercise at the College of Dentistry, University of Dammam, Saudi Arabia, in January 2015. Instructors blindly and independently scored 19-20 anonymous students' procedures, filling forms with rating scales as used in preclinical lab sessions. Their scores were compared to those of gold standard instructors in the same specialty. Percent agreement and having one letter grade difference from gold standard instructors were assessed, and associated factors were investigated after controlling for the effect of specialty/student. Agreement between instructors and their specialty gold standards occurred in 54.3% of decisions, with only 12.8% similar scores and 52.8% of scores representing underestimation in relation to gold standards. Instructor-related variables accounted for 40-50% of the variation in percent score as well as percent agreement and percent difference between instructors and gold standards. Educational background and teaching experience were significantly associated with less agreement among instructors and odds of one letter grade difference. Modest agreement existed among instructors in scoring various preclinical procedures, and there was a considerable percentage of one letter grade difference from gold standard instructors. Some factors associated with these outcomes are non-modifiable, but corrective measures are needed to increase agreement in scoring among instructors.

  11. Mortality scoring in ITU.

    PubMed

    Niewiński, Grzegorz; Kański, Andrzej

    2012-01-01

    Chronic shortage of ITU beds makes decisions on admission difficult and responsible. The use of computer-based mortality scoring should help in decision-making and for this purpose, a number of different scoring systems have been created; in principle, they should be easy to use, adaptable to all populations of patients and suitable for predicting the risk of mortality during both ITU and hospital stay. Most of existing scales and scoring systems were included in this review. They are frequently used in ITUs and become a necessary tool to describe ITU populations and to explain differences in mortality. As there are several pitfalls related to the interpretation of the numbers supplied by the systems, they should be used with the knowledge on the severity scoring science. Moreover, the cost and significant workload limit the use of scoring systems; in many cases an extra person has to be employed for collection and analysis of data only.

  12. Reduction in Dynamic Visual Acuity Reveals Gaze Control Changes Following Spaceflight

    NASA Technical Reports Server (NTRS)

    Peters, Brian T.; Brady, Rachel A.; Miller, Chris; Lawrence, Emily L.; Mulavara Ajitkumar P.; Bloomberg, Jacob J.

    2010-01-01

    INTRODUCTION: Exposure to microgravity causes adaptive changes in eye-head coordination that can lead to altered gaze control. This could affect postflight visual acuity during head and body motion. The goal of this study was to characterize changes in dynamic visual acuity after long-duration spaceflight. METHODS: Dynamic Visual Acuity (DVA) data from 14 astro/cosmonauts were collected after long-duration (6 months) spaceflight. The difference in acuity between seated and walking conditions provided a metric of change in the subjects ability to maintain gaze fixation during self-motion. In each condition, a psychophysical threshold detection algorithm was used to display Landolt ring optotypes at a size that was near each subject s acuity threshold. Verbal responses regarding the orientation of the gap were recorded as the optotypes appeared sequentially on a computer display 4 meters away. During the walking trials, subjects walked at 6.4 km/h on a motorized treadmill. RESULTS: A decrement in mean postflight DVA was found, with mean values returning to baseline within 1 week. The population mean showed a consistent improvement in DVA performance, but it was accompanied by high variability. A closer examination of the individual subject s recovery curves revealed that many did not follow a pattern of continuous improvement with each passing day. When adjusted on the basis of previous long-duration flight experience, the population mean shows a "bounce" in the re-adaptation curve. CONCLUSION: Gaze control during self-motion is altered following long-duration spaceflight and changes in postflight DVA performance indicate that vestibular re-adaptation may be more complex than a gradual return to normal.

  13. A Systematic Investigation of Accuracy and Response Time Based Measures Used to Index ANS Acuity

    PubMed Central

    Dietrich, Julia Felicitas; Huber, Stefan; Klein, Elise; Willmes, Klaus; Pixner, Silvia; Moeller, Korbinian

    2016-01-01

    The approximate number system (ANS) was proposed to be a building block for later mathematical abilities. Several measures have been used interchangeably to assess ANS acuity. Some of these measures were based on accuracy data, whereas others relied on response time (RT) data or combined accuracy and RT data. Previous studies challenged the view that all these measures can be used interchangeably, because low correlations between some of the measures had been observed. These low correlations might be due to poor reliability of some of the measures, since the majority of these measures are mathematically related. Here we systematically investigated the relationship between common ANS measures while avoiding the potential confound of poor reliability. Our first experiment revealed high correlations between all accuracy based measures supporting the assumption that all of them can be used interchangeably. In contrast, not all RT based measures were highly correlated. Additionally, our results revealed a speed-accuracy trade-off. Thus, accuracy and RT based measures provided conflicting conclusions regarding ANS acuity. Therefore, we investigated in two further experiments which type of measure (accuracy or RT) is more informative about the underlying ANS acuity, depending on participants’ preferences for accuracy or speed. To this end, we manipulated participants’ preferences for accuracy or speed both explicitly using different task instructions and implicitly varying presentation duration. Accuracy based measures were more informative about the underlying ANS acuity than RT based measures. Moreover, the influence of the underlying representations on accuracy data was more pronounced when participants preferred accuracy over speed after the accuracy instruction as well as for long or unlimited presentation durations. Implications regarding the diffusion model as a theoretical framework of dot comparison as well as regarding the relationship between ANS acuity and

  14. Foveal photoreceptor explanation of short-term visual acuity recovery associated with laser-induced foveal damage

    NASA Astrophysics Data System (ADS)

    Langus, Amir; Zwick, Harry; Stuck, Bruce E.; Belkin, Michael

    2003-06-01

    Both human laser accident cases and non-human primate behavioral studies demonstrate the possibility of full visual acuity recovery following foveal laser injury. Current explanations of such recovery require suppositions of complex retinal reorganization dynamics or neural reorganization at higher order visual brain systems. However, recent investigation based on data of retinal photoreceptor and ganglion cell topography and connectivity, suggest that the amount of static inherent plasticity, already exists at the retinal level, may also explain visual acuity recovery in the presence of laser-induced foveal damage. Modeling the off-axis visual acuity while utilizing this data, produces a more gradual fall-off in visual acuity, and supports the notion that visual acuity recovery may reside in the topographical organization of the cones. Moreover, considering the filling-in phenomena, which can conceal the presence of retinal damage from being recognized, together with eye movements, could nullify scotoma, as long as the retinal damage is not too extensive.

  15. 50 CFR 216.257 - Letters of Authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MAMMALS Taking Marine Mammals Incidental to Conducting Precision Strike Weapon Missions in the Gulf of Mexico § 216.257 Letters of Authorization. (a) A Letter of Authorization, unless suspended or...

  16. 50 CFR 216.257 - Letters of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MAMMALS Taking Marine Mammals Incidental to Conducting Precision Strike Weapon Missions in the Gulf of Mexico § 216.257 Letters of Authorization. (a) A Letter of Authorization, unless suspended or...

  17. 50 CFR 218.237 - Applications for Letters of Authorization.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Array Sensor System Low Frequency Active (SURTASS LFA) Sonar § 218.237 Applications for Letters of... scheduled to begin conducting SURTASS LFA sonar operations or the previous Letter of Authorization...

  18. 50 CFR 216.187 - Applications for Letters of Authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Array Sensor System Low Frequency Active (SURTASS LFA sonar) Sonar § 216.187 Applications for Letters of... scheduled to begin conducting SURTASS LFA sonar operations or the previous Letter of Authorization...

  19. 50 CFR 218.237 - Applications for Letters of Authorization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Array Sensor System Low Frequency Active (SURTASS LFA) Sonar § 218.237 Applications for Letters of... scheduled to begin conducting SURTASS LFA sonar operations or the previous Letter of Authorization...

  20. 50 CFR 216.187 - Applications for Letters of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Array Sensor System Low Frequency Active (SURTASS LFA sonar) Sonar § 216.187 Applications for Letters of... scheduled to begin conducting SURTASS LFA sonar operations or the previous Letter of Authorization...

  1. 50 CFR 218.16 - Letters of Authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MAMMALS Taking Marine Mammals Incidental to U.S. Navy Training in the Jacksonville Range Complex (JAX Range Complex) § 218.16 Letters of Authorization. (a) A Letter of Authorization, unless suspended...

  2. 50 CFR 216.277 - Letters of Authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MAMMALS Taking Marine Mammals Incidental to U.S. Navy Training in the Southern California Range Complex (SOCAL Range Complex) § 216.277 Letters of Authorization. (a) A Letter of Authorization, unless...

  3. 50 CFR 218.7 - Letters of Authorization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MAMMALS Taking Marine Mammals Incidental to U.S. Navy Training in the Virginia Capes Range Complex (VACAPES Range Complex) § 218.7 Letters of Authorization. (a) A Letter of Authorization, unless...

  4. 46 CFR 3.05-1 - Letter of designation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OCEANOGRAPHIC RESEARCH VESSELS Definition of Terms Used in This Part § 3.05-1 Letter of designation. A letter issued by an Officer in Charge, Marine Inspection, designating an uninspected vessel as an...

  5. 50 CFR 218.176 - Letters of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Complex and the Associated Proposed Extensions Study Area § 218.176 Letters of Authorization. (a) A Letter... determination that the total number of marine mammals taken by the activity as a whole will have no more than...

  6. 50 CFR 217.76 - Letter of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Kodiak Launch Complex, Alaska § 217.76 Letter of Authorization. (a) A Letter of Authorization, unless... number of marine mammals, by species and age class, authorized to be taken; (2) Permissible methods...

  7. The Letters Not Sent by a Journal Editor

    NASA Astrophysics Data System (ADS)

    2013-04-01

    In the late hours of the night, even the most conscientious of journal editors may slip into writing imaginary letters to cherished authors and reviewers. Here are some of the letters that I composed:

  8. EPA Letters to the Department of Treasury (IRS) for FRAP

    EPA Pesticide Factsheets

    EPA letter of request (December 13, 2012) and letter of reply (April 30, 2013) to IRS to address FRAP commitment to facilitate the deductibility of radon testing and mitigation costs within Health Care Savings Accounts (HSAs).

  9. When writing impairs reading: letter perception's susceptibility to motor interference.

    PubMed

    James, Karin H; Gauthier, Isabel

    2009-08-01

    The effect of writing on the concurrent visual perception of letters was investigated in a series of studies using an interference paradigm. Participants drew shapes and letters while simultaneously visually identifying letters and shapes embedded in noise. Experiments 1-3 demonstrated that letter perception, but not the perception of shapes, was affected by motor interference. This suggests a strong link between the perception of letters and the neural substrates engaged during writing. The overlap both in category (letter vs. shape) and in the perceptual similarity of the features (straight vs. curvy) of the seen and drawn items determined the amount of interference. Experiment 4 demonstrated that intentional production of letters is not necessary for the interference to occur, because passive movement of the hand in the shape of letters also interfered with letter perception. When passive movements were used, however, only the category of the drawn items (letters vs. shapes), but not the perceptual similarity, had an influence, suggesting that motor representations for letters may selectively influence visual perception of letters through proprioceptive feedback, with an additional influence of perceptual similarity that depends on motor programs.

  10. The Castleman Letter: A Classroom Exercise in Critical Thinking.

    ERIC Educational Resources Information Center

    Shapiro, Victor W.

    1981-01-01

    Describes a critical thinking activity for secondary school social studies students using a letter written in the nineteenth century. The letter contains references to unfamiliar people and events. Through research, students are able to trace the exact date of the letter and to identify the people and events. (KC)

  11. 33 CFR 401.68 - Explosives Permission Letter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Explosives Permission Letter. 401..., DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Dangerous Cargo § 401.68 Explosives Permission Letter. (a) A Seaway Explosives Permission Letter is required for an explosive vessel in...

  12. 33 CFR 401.68 - Explosives Permission Letter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Explosives Permission Letter. 401..., DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Dangerous Cargo § 401.68 Explosives Permission Letter. (a) A Seaway Explosives Permission Letter is required for an explosive vessel in...

  13. 33 CFR 401.68 - Explosives Permission Letter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Explosives Permission Letter. 401..., DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Dangerous Cargo § 401.68 Explosives Permission Letter. (a) A Seaway Explosives Permission Letter is required for an explosive vessel in...

  14. 33 CFR 401.68 - Explosives Permission Letter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Explosives Permission Letter. 401..., DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Dangerous Cargo § 401.68 Explosives Permission Letter. (a) A Seaway Explosives Permission Letter is required for an explosive vessel in...

  15. 33 CFR 401.68 - Explosives permission letter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Explosives permission letter. 401..., DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Dangerous Cargo § 401.68 Explosives permission letter. (a) A Seaway Explosives Permission Letter is required for an explosive vessel in...

  16. 19 CFR 162.4 - Search for letters.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Search for letters. 162.4 Section 162.4 Customs... (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.4 Search for letters. A Customs officer may search vessels for letters which may be on board or may have been conveyed contrary...

  17. 19 CFR 162.4 - Search for letters.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Search for letters. 162.4 Section 162.4 Customs... (CONTINUED) INSPECTION, SEARCH, AND SEIZURE Inspection, Examination, and Search § 162.4 Search for letters. A Customs officer may search vessels for letters which may be on board or may have been conveyed contrary...

  18. 76 FR 63237 - Issuance of Investigation Completion Letters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-12

    ... Part 571 RIN 3141-AA49 Issuance of Investigation Completion Letters AGENCY: National Indian Gaming... regulations to provide for an investigation completion letter to be issued to a Tribe if the Agency's... a process for issuing an investigation completion letter. The Notice of Regulatory Review...

  19. 50 CFR 218.16 - Letters of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MAMMALS Taking Marine Mammals Incidental to U.S. Navy Training in the Jacksonville Range Complex (JAX Range Complex) § 218.16 Letters of Authorization. (a) A Letter of Authorization, unless suspended or... and renewal of the Letter of Authorization will be based on a determination that the total number...

  20. 50 CFR 218.7 - Letters of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MAMMALS Taking Marine Mammals Incidental to U.S. Navy Training in the Virginia Capes Range Complex (VACAPES Range Complex) § 218.7 Letters of Authorization. (a) A Letter of Authorization, unless suspended... and renewal of the Letter of Authorization will be based on a determination that the total number...

  1. 50 CFR 216.277 - Letters of Authorization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MAMMALS Taking Marine Mammals Incidental to U.S. Navy Training in the Southern California Range Complex (SOCAL Range Complex) § 216.277 Letters of Authorization. (a) A Letter of Authorization, unless suspended... and renewal of the Letter of Authorization will be based on a determination that the total number...

  2. Transposed-Letter and Laterality Effects in Lexical Decision

    ERIC Educational Resources Information Center

    Perea, Manuel; Fraga, Isabel

    2006-01-01

    Two divided visual field lexical decision experiments were conducted to examine the role of the cerebral hemispheres in transposed-letter similarity effects. In Experiment 1, we created two types of nonwords: nonadjacent transposed-letter nonwords ("TRADEGIA"; the base word was "TRAGEDIA," the Spanish for "TRAGEDY") and two-letter different…

  3. 48 CFR 871.201-4 - Letter contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Letter contracts. 871.201... Rehabilitation and Employment Service 871.201-4 Letter contracts. Letter contracts are authorized for use in... formal contract with an approved educational institution before the enrollment of eligible veterans...

  4. 48 CFR 871.201-4 - Letter contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Letter contracts. 871.201... Rehabilitation and Employment Service 871.201-4 Letter contracts. Letter contracts are authorized for use in... formal contract with an approved educational institution before the enrollment of eligible veterans...

  5. 48 CFR 871.201-4 - Letter contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Letter contracts. 871.201... Rehabilitation and Employment Service 871.201-4 Letter contracts. Letter contracts are authorized for use in... formal contract with an approved educational institution before the enrollment of eligible veterans...

  6. 22 CFR 92.54 - “Letters rogatory” defined.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false âLetters rogatoryâ defined. 92.54 Section 92.54 Foreign Relations DEPARTMENT OF STATE LEGAL AND RELATED SERVICES NOTARIAL AND RELATED SERVICES Depositions and Letters Rogatory § 92.54 “Letters rogatory” defined. In its broader sense in...

  7. The Letter of Recommendation: A Key to Women's Career Equity.

    ERIC Educational Resources Information Center

    Cowan, Gloria; Kasen, Jill

    A critical piece of information in the selection process for academic positions is the letter of recommendation. A study was conducted to determine if differences exist in the letters written for female versus male candidates for academic positions. Using letters which were retyped to avoid personal, institutional, and sex-specific identification,…

  8. 31 CFR 535.416 - Letters of credit.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Letters of credit. 535.416 Section... § 535.416 Letters of credit. (a) Question. Prior to the effective date, a bank subject to the jurisdiction of the United States has issued or confirmed a documentary letter of credit for a...

  9. 48 CFR 52.228-14 - Irrevocable Letter of Credit.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Credit. 52.228-14 Section 52.228-14 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION....228-14 Irrevocable Letter of Credit. As prescribed in 28.204-4, insert the following clause: Irrevocable Letter of Credit (DEC 1999) (a) “Irrevocable letter of credit” (ILC), as used in this...

  10. 48 CFR 52.228-14 - Irrevocable Letter of Credit.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Credit. 52.228-14 Section 52.228-14 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION....228-14 Irrevocable Letter of Credit. As prescribed in 28.204-4, insert the following clause: Irrevocable Letter of Credit (MAY 2014) (a) “Irrevocable letter of credit” (ILC), as used in this...

  11. 31 CFR 535.416 - Letters of credit.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Letters of credit. 535.416 Section 535... § 535.416 Letters of credit. (a) Question. Prior to the effective date, a bank subject to the jurisdiction of the United States has issued or confirmed a documentary letter of credit for a...

  12. 47 CFR 54.1007 - Letter of credit.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Letter of credit. 54.1007 Section 54.1007... SERVICE Mobility Fund § 54.1007 Letter of credit. (a) Before being authorized to receive Mobility Fund Phase I support, a winning bidder shall obtain an irrevocable standby letter of credit which shall...

  13. 47 CFR 54.1007 - Letter of credit.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Letter of credit. 54.1007 Section 54.1007... SERVICE Mobility Fund § 54.1007 Letter of credit. (a) Before being authorized to receive Mobility Fund Phase I support, a winning bidder shall obtain an irrevocable standby letter of credit which shall...

  14. 40 CFR 280.99 - Letter of credit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Letter of credit. 280.99 Section 280... (UST) Financial Responsibility § 280.99 Letter of credit. (a) An owner or operator may satisfy the requirements of § 280.93 by obtaining an irrevocable standby letter of credit that conforms to the...

  15. 31 CFR 535.416 - Letters of credit.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Letters of credit. 535.416 Section 535... § 535.416 Letters of credit. (a) Question. Prior to the effective date, a bank subject to the jurisdiction of the United States has issued or confirmed a documentary letter of credit for a...

  16. 48 CFR 52.228-14 - Irrevocable Letter of Credit.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Credit. 52.228-14 Section 52.228-14 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION....228-14 Irrevocable Letter of Credit. As prescribed in 28.204-4, insert the following clause: Irrevocable Letter of Credit (DEC 1999) (a) “Irrevocable letter of credit” (ILC), as used in this...

  17. 48 CFR 52.228-14 - Irrevocable Letter of Credit.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Credit. 52.228-14 Section 52.228-14 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION....228-14 Irrevocable Letter of Credit. As prescribed in 28.204-4, insert the following clause: Irrevocable Letter of Credit (DEC 1999) (a) “Irrevocable letter of credit” (ILC), as used in this...

  18. 31 CFR 535.416 - Letters of credit.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Letters of credit. 535.416 Section 535... § 535.416 Letters of credit. (a) Question. Prior to the effective date, a bank subject to the jurisdiction of the United States has issued or confirmed a documentary letter of credit for a...

  19. The Relationship between Letter Fluency Measures and Arabic GPA

    ERIC Educational Resources Information Center

    Al-Hmouz, Hanan

    2013-01-01

    This study investigated two widely-used early literacy skill's indicators in reflecting growth in first-grade language achievement skills. It compared two curriculum-based assessments of letter knowledge: Letter Naming Fluency (LNF) and Letter Sound Fluency (LSF) in the Arabic language. A sample of 125 first-grade students, 100 average readers and…

  20. 46 CFR 131.930 - Display of stability letter.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Display of stability letter. 131.930 Section 131.930 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Miscellaneous § 131.930 Display of stability letter. If the Coast Guard issues a stability letter under §...