A Simple Device for Morphofunctional Evaluation During Aortic Valve-Sparing Surgery.

PubMed

Leone, Alessandro; Bruno, Piergiorgio; Cammertoni, Federico; Massetti, Massimo

2015-07-01

Valve-sparing operations for the treatment of aortic root disease with a structurally normal aortic valve are increasingly performed as they avoid prosthesis-related complications. Short- and long-term results are critically dependent on perfect intraoperative restoration of valve anatomy and function. Residual aortic regurgitation is the main cause of early failure, and it is the most common motive for reoperation. However, intraoperative morphofunctional valve assessment requires expertise, and only transesophageal echocardiography can provide reliable information. We describe a simple, economic, reproducible hydrostatic test to intraoperatively evaluate valve competency under direct visualization. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

The shaping of information by visual metaphors.

PubMed

Ziemkiewicz, Caroline; Kosara, Robert

2008-01-01

The nature of an information visualization can be considered to lie in the visual metaphors it uses to structure information. The process of understanding a visualization therefore involves an interaction between these external visual metaphors and the user's internal knowledge representations. To investigate this claim, we conducted an experiment to test the effects of visual metaphor and verbal metaphor on the understanding of tree visualizations. Participants answered simple data comprehension questions while viewing either a treemap or a node-link diagram. Questions were worded to reflect a verbal metaphor that was either compatible or incompatible with the visualization a participant was using. The results (based on correctness and response time) suggest that the visual metaphor indeed affects how a user derives information from a visualization. Additionally, we found that the degree to which a user is affected by the metaphor is strongly correlated with the user's ability to answer task questions correctly. These findings are a first step towards illuminating how visual metaphors shape user understanding, and have significant implications for the evaluation, application, and theory of visualization.

Teaching Technical and Business Writing: Strategies and Evaluation.

ERIC Educational Resources Information Center

Alexander, Clara

1985-01-01

Describes a course that gives students the kinds of writing and oral communication experiences they will need on the job. The course gives students information about effective speaking and teaches them how to write business letters, prepare simple visuals for written and oral reports, and write formal proposals. (EL)

Does my step look big in this? A visual illusion leads to safer stepping behaviour.

PubMed

Elliott, David B; Vale, Anna; Whitaker, David; Buckley, John G

2009-01-01

Tripping is a common factor in falls and a typical safety strategy to avoid tripping on steps or stairs is to increase foot clearance over the step edge. In the present study we asked whether the perceived height of a step could be increased using a visual illusion and whether this would lead to the adoption of a safer stepping strategy, in terms of greater foot clearance over the step edge. The study also addressed the controversial question of whether motor actions are dissociated from visual perception. 21 young, healthy subjects perceived the step to be higher in a configuration of the horizontal-vertical illusion compared to a reverse configuration (p = 0.01). During a simple stepping task, maximum toe elevation changed by an amount corresponding to the size of the visual illusion (p<0.001). Linear regression analyses showed highly significant associations between perceived step height and maximum toe elevation for all conditions. The perceived height of a step can be manipulated using a simple visual illusion, leading to the adoption of a safer stepping strategy in terms of greater foot clearance over a step edge. In addition, the strong link found between perception of a visual illusion and visuomotor action provides additional support to the view that the original, controversial proposal by Goodale and Milner (1992) of two separate and distinct visual streams for perception and visuomotor action should be re-evaluated.

A simple and efficient method to visualize and quantify the efficiency of chromosomal mutations from genome editing

PubMed Central

Fu, Liezhen; Wen, Luan; Luu, Nga; Shi, Yun-Bo

2016-01-01

Genome editing with designer nucleases such as TALEN and CRISPR/Cas enzymes has broad applications. Delivery of these designer nucleases into organisms induces various genetic mutations including deletions, insertions and nucleotide substitutions. Characterizing those mutations is critical for evaluating the efficacy and specificity of targeted genome editing. While a number of methods have been developed to identify the mutations, none other than sequencing allows the identification of the most desired mutations, i.e., out-of-frame insertions/deletions that disrupt genes. Here we report a simple and efficient method to visualize and quantify the efficiency of genomic mutations induced by genome-editing. Our approach is based on the expression of a two-color fusion protein in a vector that allows the insertion of the edited region in the genome in between the two color moieties. We show that our approach not only easily identifies developing animals with desired mutations but also efficiently quantifies the mutation rate in vivo. Furthermore, by using LacZα and GFP as the color moieties, our approach can even eliminate the need for a fluorescent microscope, allowing the analysis with simple bright field visualization. Such an approach will greatly simplify the screen for effective genome-editing enzymes and identify the desired mutant cells/animals. PMID:27748423

A simple quality assurance test tool for the visual verification of light and radiation field congruent using electronic portal images device and computed radiography

PubMed Central

2012-01-01

Background The radiation field on most megavoltage radiation therapy units are shown by a light field projected through the collimator by a light source mounted inside the collimator. The light field is traditionally used for patient alignment. Hence it is imperative that the light field is congruent with the radiation field. Method A simple quality assurance tool has been designed for rapid and simple test of the light field and radiation field using electronic portal images device (EPID) or computed radiography (CR). We tested this QA tool using Varian PortalVision and Elekta iViewGT EPID systems and Kodak CR system. Results Both the single and double exposure techniques were evaluated, with double exposure technique providing a better visualization of the light-radiation field markers. The light and radiation congruency could be detected within 1 mm. This will satisfy the American Association of Physicists in Medicine task group report number 142 recommendation of 2 mm tolerance. Conclusion The QA tool can be used with either an EPID or CR to provide a simple and rapid method to verify light and radiation field congruence. PMID:22452821

Image quality evaluation of full reference algorithm

NASA Astrophysics Data System (ADS)

He, Nannan; Xie, Kai; Li, Tong; Ye, Yushan

2018-03-01

Image quality evaluation is a classic research topic, the goal is to design the algorithm, given the subjective feelings consistent with the evaluation value. This paper mainly introduces several typical reference methods of Mean Squared Error(MSE), Peak Signal to Noise Rate(PSNR), Structural Similarity Image Metric(SSIM) and feature similarity(FSIM) of objective evaluation methods. The different evaluation methods are tested by Matlab, and the advantages and disadvantages of these methods are obtained by analyzing and comparing them.MSE and PSNR are simple, but they are not considered to introduce HVS characteristics into image quality evaluation. The evaluation result is not ideal. SSIM has a good correlation and simple calculation ,because it is considered to the human visual effect into image quality evaluation,However the SSIM method is based on a hypothesis,The evaluation result is limited. The FSIM method can be used for test of gray image and color image test, and the result is better. Experimental results show that the new image quality evaluation algorithm based on FSIM is more accurate.

Reliability and Validity of the Visual, Musculoskeletal, and Balance Complaints Questionnaire.

PubMed

Lundqvist, Lars-Olov; Zetterlund, Christina; Richter, Hans O

2016-09-01

To evaluate the reliability and validity of the 15-item Visual, Musculoskeletal, and Balance Complaints Questionnaire (VMB) for people with visual impairments, using confirmatory factor analysis (CFA) and with Rasch analysis for use as an outcome measure. Two studies evaluated the VMB. In Study 1, VMB data were collected from 1249 out of 3063 individuals between 18 and 104 years old who were registered at a low vision center. CFA evaluated VMB factor structure and Rasch analysis evaluated VMB scale properties. In Study 2, a subsample of 52 individuals between 27 and 67 years old with visual impairments underwent further measurements. Visual clinical assessments, neck/scapular pain, and balance assessments were collected to evaluate the convergent validity of the VMB (i.e. the domain relationship with other, theoretically predicted measures). CFA supported the a priori three-factor structure of the VMB. The factor loadings of the items on their respective domains were all statistically significant. Rasch analysis indicated disordered categories and the original 10-point scale was subsequently replaced with a 5-point scale. Each VMB domain fitted the Rasch model, showing good metric properties, including unidimensionality (explained variances ≥66% and eigenvalues <1.9), person separation (1.86 to 2.29), reliability (0.87 to 0.94), item fit (infit MnSq's >0.72 and outfit MnSq's <1.47), targeting (0.30 to 0.50 logits), and insignificant differential item functioning (all DIFs but one <0.50 logits) from gender, age, and visual status. The three VMB domains correlated significantly with relevant visual, musculoskeletal, and balance assessments, demonstrating adequate convergent validity of the VMB. The VMB is a simple, inexpensive, and quick yet reliable and valid way to screen and evaluate concurrent visual, musculoskeletal, and balance complaints, with contribution to epidemiological and intervention research and potential clinical implications for the field of health services and low vision rehabilitation.

Reliability and Validity of the Visual, Musculoskeletal, and Balance Complaints Questionnaire

PubMed Central

Lundqvist, Lars-Olov; Zetterlund, Christina; Richter, Hans O.

2016-01-01

ABSTRACT Purpose To evaluate the reliability and validity of the 15-item Visual, Musculoskeletal, and Balance Complaints Questionnaire (VMB) for people with visual impairments, using confirmatory factor analysis (CFA) and with Rasch analysis for use as an outcome measure. Methods Two studies evaluated the VMB. In Study 1, VMB data were collected from 1249 out of 3063 individuals between 18 and 104 years old who were registered at a low vision center. CFA evaluated VMB factor structure and Rasch analysis evaluated VMB scale properties. In Study 2, a subsample of 52 individuals between 27 and 67 years old with visual impairments underwent further measurements. Visual clinical assessments, neck/scapular pain, and balance assessments were collected to evaluate the convergent validity of the VMB (i.e. the domain relationship with other, theoretically predicted measures). Results CFA supported the a priori three-factor structure of the VMB. The factor loadings of the items on their respective domains were all statistically significant. Rasch analysis indicated disordered categories and the original 10-point scale was subsequently replaced with a 5-point scale. Each VMB domain fitted the Rasch model, showing good metric properties, including unidimensionality (explained variances ≥66% and eigenvalues <1.9), person separation (1.86 to 2.29), reliability (0.87 to 0.94), item fit (infit MnSq’s >0.72 and outfit MnSq’s <1.47), targeting (0.30 to 0.50 logits), and insignificant differential item functioning (all DIFs but one <0.50 logits) from gender, age, and visual status. The three VMB domains correlated significantly with relevant visual, musculoskeletal, and balance assessments, demonstrating adequate convergent validity of the VMB. Conclusions The VMB is a simple, inexpensive, and quick yet reliable and valid way to screen and evaluate concurrent visual, musculoskeletal, and balance complaints, with contribution to epidemiological and intervention research and potential clinical implications for the field of health services and low vision rehabilitation. PMID:27309524

Mastering algebra retrains the visual system to perceive hierarchical structure in equations.

PubMed

Marghetis, Tyler; Landy, David; Goldstone, Robert L

2016-01-01

Formal mathematics is a paragon of abstractness. It thus seems natural to assume that the mathematical expert should rely more on symbolic or conceptual processes, and less on perception and action. We argue instead that mathematical proficiency relies on perceptual systems that have been retrained to implement mathematical skills. Specifically, we investigated whether the visual system-in particular, object-based attention-is retrained so that parsing algebraic expressions and evaluating algebraic validity are accomplished by visual processing. Object-based attention occurs when the visual system organizes the world into discrete objects, which then guide the deployment of attention. One classic signature of object-based attention is better perceptual discrimination within, rather than between, visual objects. The current study reports that object-based attention occurs not only for simple shapes but also for symbolic mathematical elements within algebraic expressions-but only among individuals who have mastered the hierarchical syntax of algebra. Moreover, among these individuals, increased object-based attention within algebraic expressions is associated with a better ability to evaluate algebraic validity. These results suggest that, in mastering the rules of algebra, people retrain their visual system to represent and evaluate abstract mathematical structure. We thus argue that algebraic expertise involves the regimentation and reuse of evolutionarily ancient perceptual processes. Our findings implicate the visual system as central to learning and reasoning in mathematics, leading us to favor educational approaches to mathematics and related STEM fields that encourage students to adapt, not abandon, their use of perception.

A Simple Visualization of Double Bond Properties: Chemical Reactivity and UV Fluorescence

ERIC Educational Resources Information Center

Grayson, Scott M.

2012-01-01

A simple, easily visualized thin-layer chromatography (TLC) staining experiment is presented that highlights the difference in reactivity between aromatic double bonds and nonaromatic double bonds. Although the stability of aromatic systems is a major theme in organic chemistry, the concept is rarely reinforced "visually" in the undergraduate…

Acoustic-tactile rendering of visual information

NASA Astrophysics Data System (ADS)

Silva, Pubudu Madhawa; Pappas, Thrasyvoulos N.; Atkins, Joshua; West, James E.; Hartmann, William M.

2012-03-01

In previous work, we have proposed a dynamic, interactive system for conveying visual information via hearing and touch. The system is implemented with a touch screen that allows the user to interrogate a two-dimensional (2-D) object layout by active finger scanning while listening to spatialized auditory feedback. Sound is used as the primary source of information for object localization and identification, while touch is used both for pointing and for kinesthetic feedback. Our previous work considered shape and size perception of simple objects via hearing and touch. The focus of this paper is on the perception of a 2-D layout of simple objects with identical size and shape. We consider the selection and rendition of sounds for object identification and localization. We rely on the head-related transfer function for rendering sound directionality, and consider variations of sound intensity and tempo as two alternative approaches for rendering proximity. Subjective experiments with visually-blocked subjects are used to evaluate the effectiveness of the proposed approaches. Our results indicate that intensity outperforms tempo as a proximity cue, and that the overall system for conveying a 2-D layout is quite promising.

Ontogeny and Sexual Differences in Swimming Proximity to Conspecifics in Response to Visual Cues in Medaka Fish.

PubMed

Isoe, Yasuko; Konagaya, Yumi; Yokoi, Saori; Kubo, Takeo; Takeuchi, Hideaki

2016-06-01

Adult medaka fish (Oryzias latipes) exhibit complex social behaviors that depend mainly on visual cues from conspecifics. The ontogeny of visually-mediated social behaviors from larval/juvenile to adult medaka fish, however, is unknown. In the present study, we established a simple behavioral paradigm to evaluate the swimming proximity to conspecifics based on visual cues in an inter-individual interaction of two medaka fish throughout life. When two fish were placed separately in a cylindrical tank with a concentric transparent wall, the two fish maintained close proximity to each other. A normal fish inside the tank maintained proximity to an optic nerve-cut fish outside of the tank, while the converse was not true. This behavioral paradigm enabled us to quantify visually-induced motivation of a single fish inside the tank. The proximity was detected from larval/juvenile to adult fish. Larval fish, however, maintained close proximity not only to conspecifics, but also to heterospecifics. As the growth stage increased, the degree of proximity to heterospecifics decreased, suggesting that shoaling preferences toward conspecifics and/or visual ability to recognize conspecifics is refined and established according to the growth stage. Furthermore, the proximity of adult female fish was affected by their reproductive status and social familiarity. Only before spawning, adult females maintained closer proximity to familiar males rather than to unfamiliar males, suggesting that proximity was affected by familiarity in a female-specific manner. This simple behavioral paradigm will contribute to our understanding of the neural basis of the development of visually-mediated social behavior using medaka fish.

Spatiotemporal video deinterlacing using control grid interpolation

NASA Astrophysics Data System (ADS)

Venkatesan, Ragav; Zwart, Christine M.; Frakes, David H.; Li, Baoxin

2015-03-01

With the advent of progressive format display and broadcast technologies, video deinterlacing has become an important video-processing technique. Numerous approaches exist in the literature to accomplish deinterlacing. While most earlier methods were simple linear filtering-based approaches, the emergence of faster computing technologies and even dedicated video-processing hardware in display units has allowed higher quality but also more computationally intense deinterlacing algorithms to become practical. Most modern approaches analyze motion and content in video to select different deinterlacing methods for various spatiotemporal regions. We introduce a family of deinterlacers that employs spectral residue to choose between and weight control grid interpolation based spatial and temporal deinterlacing methods. The proposed approaches perform better than the prior state-of-the-art based on peak signal-to-noise ratio, other visual quality metrics, and simple perception-based subjective evaluations conducted by human viewers. We further study the advantages of using soft and hard decision thresholds on the visual performance.

The Subjective Visual Vertical: Validation of a Simple Test

ERIC Educational Resources Information Center

Tesio, Luigi; Longo, Stefano; Rota, Viviana

2011-01-01

The study sought to provide norms for a simple test of visual perception of verticality (subjective visual vertical). The study was designed as a cohort study with a balanced design. The setting was the Rehabilitation Department of a University Hospital. Twenty-two healthy adults, of 23-58 years, 11 men (three left handed) and 11 women (three left…

SIMPL: A Simplified Model-Based Program for the Analysis and Visualization of Groundwater Rebound in Abandoned Mines to Prevent Contamination of Water and Soils by Acid Mine Drainage

PubMed Central

Kim, Sung-Min

2018-01-01

Cessation of dewatering following underground mine closure typically results in groundwater rebound, because mine voids and surrounding strata undergo flooding up to the levels of the decant points, such as shafts and drifts. SIMPL (Simplified groundwater program In Mine workings using the Pipe equation and Lumped parameter model), a simplified lumped parameter model-based program for predicting groundwater levels in abandoned mines, is presented herein. The program comprises a simulation engine module, 3D visualization module, and graphical user interface, which aids data processing, analysis, and visualization of results. The 3D viewer facilitates effective visualization of the predicted groundwater level rebound phenomenon together with a topographic map, mine drift, goaf, and geological properties from borehole data. SIMPL is applied to data from the Dongwon coal mine and Dalsung copper mine in Korea, with strong similarities in simulated and observed results. By considering mine workings and interpond connections, SIMPL can thus be used to effectively analyze and visualize groundwater rebound. In addition, the predictions by SIMPL can be utilized to prevent the surrounding environment (water and soil) from being polluted by acid mine drainage. PMID:29747480

Measuring the effect of attention on simple visual search.

PubMed

Palmer, J; Ames, C T; Lindsey, D T

1993-02-01

Set-size in visual search may be due to 1 or more of 3 factors: sensory processes such as lateral masking between stimuli, attentional processes limiting the perception of individual stimuli, or attentional processes affecting the decision rules for combining information from multiple stimuli. These possibilities were evaluated in tasks such as searching for a longer line among shorter lines. To evaluate sensory contributions, display set-size effects were compared with cuing conditions that held sensory phenomena constant. Similar effects for the display and cue manipulations suggested that sensory processes contributed little under the conditions of this experiment. To evaluate the contribution of decision processes, the set-size effects were modeled with signal detection theory. In these models, a decision effect alone was sufficient to predict the set-size effects without any attentional limitation due to perception.

Visual Short-Term Memory for Complex Objects in 6- and 8-Month-Old Infants

ERIC Educational Resources Information Center

Kwon, Mee-Kyoung; Luck, Steven J.; Oakes, Lisa M.

2014-01-01

Infants' visual short-term memory (VSTM) for simple objects undergoes dramatic development: Six-month-old infants can store in VSTM information about only a simple object presented in isolation, whereas 8-month-old infants can store information about simple objects presented in multiple-item arrays. This study extended this work to examine…

Word Spelling Assessment Using ICT: The Effect of Presentation Modality

ERIC Educational Resources Information Center

Sarris, Menelaos; Panagiotakopoulos, Chris

2010-01-01

Up-to-date spelling process was assessed using typical spelling-to-dictation tasks, where children's performance was evaluated mainly in terms of spelling error scores. In the present work a simple graphical computer interface is reported, aiming to investigate the effects of input modality (e.g. visual and verbal) in word spelling. The software…

Correlation of Visual Prostate Symptom Score with International Prostate Symptom Score and Uroflowmetry Parameters in Nepalese Male Patients with Lower Urinary Tract Symptoms.

PubMed

Bhomi, K K; Subedi, N; Panta, P P

2017-01-01

International prostate symptom score is a validated questionnaire used to evaluate the lower urinary tract symptoms in benign prostatic hyperplasia. Visual prostate symptom score is a new simplified symptom score with pictograms to evaluate the same. We evaluated the correlation of visual prostate symptom score with international prostate symptom score and uroflowmetry parameters in Nepalese male patients with lower urinary tract symptoms. Male patients aged ≥40 years attending the Urology clinic were enrolled in the study. They were given international prostate symptom score and visual prostate symptom score questionnaires to complete providing assistance whenever needed. Demographic data, examination findings and uroflowmetry parameters were noted. Correlation and regression analysis was used to identify correlation of the two scoring systems and uroflowmetry parameters. Among the 66 patients enrolled, only 10 (15.15%) patients were able to understand English language. There was a statistically significant correlation between total visual prostate symptom score and international prostate symptom score (r= 0.822; P<0.01). The correlations between individual scores of the two scoring systems related to force of urinary stream, frequency, nocturia and quality of life were also statistically significant. There was also a statistically significant correlation of both scores with maximum flow rate and average flow rate. There is a statistically significant correlation of visual prostate symptom score with international prostate symptom score and uroflowmetry parameters. IPSS can be replaced with simple VPSS in evaluation of lower urinary tract symptoms in elderly male patients.

Conceptual design study for an advanced cab and visual system, volume 1

NASA Technical Reports Server (NTRS)

Rue, R. J.; Cyrus, M. L.; Garnett, T. A.; Nachbor, J. W.; Seery, J. A.; Starr, R. L.

1980-01-01

A conceptual design study was conducted to define requirements for an advanced cab and visual system. The rotorcraft system integration simulator is for engineering studies in the area of mission associated vehicle handling qualities. Principally a technology survey and assessment of existing and proposed simulator visual display systems, image generation systems, modular cab designs, and simulator control station designs were performed and are discussed. State of the art survey data were used to synthesize a set of preliminary visual display system concepts of which five candidate display configurations were selected for further evaluation. Basic display concepts incorporated in these configurations included: real image projection, using either periscopes, fiber optic bundles, or scanned laser optics; and virtual imaging with helmet mounted displays. These display concepts were integrated in the study with a simulator cab concept employing a modular base for aircraft controls, crew seating, and instrumentation (or other) displays. A simple concept to induce vibration in the various modules was developed and is described. Results of evaluations and trade offs related to the candidate system concepts are given, along with a suggested weighting scheme for numerically comparing visual system performance characteristics.

Route visualization using detail lenses.

PubMed

Karnick, Pushpak; Cline, David; Jeschke, Stefan; Razdan, Anshuman; Wonka, Peter

2010-01-01

We present a method designed to address some limitations of typical route map displays of driving directions. The main goal of our system is to generate a printable version of a route map that shows the overview and detail views of the route within a single, consistent visual frame. Our proposed visualization provides a more intuitive spatial context than a simple list of turns. We present a novel multifocus technique to achieve this goal, where the foci are defined by points of interest (POI) along the route. A detail lens that encapsulates the POI at a finer geospatial scale is created for each focus. The lenses are laid out on the map to avoid occlusion with the route and each other, and to optimally utilize the free space around the route. We define a set of layout metrics to evaluate the quality of a lens layout for a given route map visualization. We compare standard lens layout methods to our proposed method and demonstrate the effectiveness of our method in generating aesthetically pleasing layouts. Finally, we perform a user study to evaluate the effectiveness of our layout choices.

A Brief Period of Postnatal Visual Deprivation Alters the Balance between Auditory and Visual Attention.

PubMed

de Heering, Adélaïde; Dormal, Giulia; Pelland, Maxime; Lewis, Terri; Maurer, Daphne; Collignon, Olivier

2016-11-21

Is a short and transient period of visual deprivation early in life sufficient to induce lifelong changes in how we attend to, and integrate, simple visual and auditory information [1, 2]? This question is of crucial importance given the recent demonstration in both animals and humans that a period of blindness early in life permanently affects the brain networks dedicated to visual, auditory, and multisensory processing [1-16]. To address this issue, we compared a group of adults who had been treated for congenital bilateral cataracts during early infancy with a group of normally sighted controls on a task requiring simple detection of lateralized visual and auditory targets, presented alone or in combination. Redundancy gains obtained from the audiovisual conditions were similar between groups and surpassed the reaction time distribution predicted by Miller's race model. However, in comparison to controls, cataract-reversal patients were faster at processing simple auditory targets and showed differences in how they shifted attention across modalities. Specifically, they were faster at switching attention from visual to auditory inputs than in the reverse situation, while an opposite pattern was observed for controls. Overall, these results reveal that the absence of visual input during the first months of life does not prevent the development of audiovisual integration but enhances the salience of simple auditory inputs, leading to a different crossmodal distribution of attentional resources between auditory and visual stimuli. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evidence for unlimited capacity processing of simple features in visual cortex

PubMed Central

White, Alex L.; Runeson, Erik; Palmer, John; Ernst, Zachary R.; Boynton, Geoffrey M.

2017-01-01

Performance in many visual tasks is impaired when observers attempt to divide spatial attention across multiple visual field locations. Correspondingly, neuronal response magnitudes in visual cortex are often reduced during divided compared with focused spatial attention. This suggests that early visual cortex is the site of capacity limits, where finite processing resources must be divided among attended stimuli. However, behavioral research demonstrates that not all visual tasks suffer such capacity limits: The costs of divided attention are minimal when the task and stimulus are simple, such as when searching for a target defined by orientation or contrast. To date, however, every neuroimaging study of divided attention has used more complex tasks and found large reductions in response magnitude. We bridged that gap by using functional magnetic resonance imaging to measure responses in the human visual cortex during simple feature detection. The first experiment used a visual search task: Observers detected a low-contrast Gabor patch within one or four potentially relevant locations. The second experiment used a dual-task design, in which observers made independent judgments of Gabor presence in patches of dynamic noise at two locations. In both experiments, blood-oxygen level–dependent (BOLD) signals in the retinotopic cortex were significantly lower for ignored than attended stimuli. However, when observers divided attention between multiple stimuli, BOLD signals were not reliably reduced and behavioral performance was unimpaired. These results suggest that processing of simple features in early visual cortex has unlimited capacity. PMID:28654964

A Computational Study of How Orientation Bias in the Lateral Geniculate Nucleus Can Give Rise to Orientation Selectivity in Primary Visual Cortex

PubMed Central

Kuhlmann, Levin; Vidyasagar, Trichur R.

2011-01-01

Controversy remains about how orientation selectivity emerges in simple cells of the mammalian primary visual cortex. In this paper, we present a computational model of how the orientation-biased responses of cells in lateral geniculate nucleus (LGN) can contribute to the orientation selectivity in simple cells in cats. We propose that simple cells are excited by lateral geniculate fields with an orientation-bias and disynaptically inhibited by unoriented lateral geniculate fields (or biased fields pooled across orientations), both at approximately the same retinotopic co-ordinates. This interaction, combined with recurrent cortical excitation and inhibition, helps to create the sharp orientation tuning seen in simple cell responses. Along with describing orientation selectivity, the model also accounts for the spatial frequency and length–response functions in simple cells, in normal conditions as well as under the influence of the GABAA antagonist, bicuculline. In addition, the model captures the response properties of LGN and simple cells to simultaneous visual stimulation and electrical stimulation of the LGN. We show that the sharp selectivity for stimulus orientation seen in primary visual cortical cells can be achieved without the excitatory convergence of the LGN input cells with receptive fields along a line in visual space, which has been a core assumption in classical models of visual cortex. We have also simulated how the full range of orientations seen in the cortex can emerge from the activity among broadly tuned channels tuned to a limited number of optimum orientations, just as in the classical case of coding for color in trichromatic primates. PMID:22013414

Influence of age, sex, and education on the Visual Object and Space Perception Battery (VOSP) in a healthy normal elderly population.

PubMed

Herrera-Guzmán, I; Peña-Casanova, J; Lara, J P; Gudayol-Ferré, E; Böhm, P

2004-08-01

The assessment of visual perception and cognition forms an important part of any general cognitive evaluation. We have studied the possible influence of age, sex, and education on a normal elderly Spanish population (90 healthy subjects) in performance in visual perception tasks. To evaluate visual perception and cognition, we have used the subjects performance with The Visual Object and Space Perception Battery (VOSP). The test consists of 8 subtests: 4 measure visual object perception (Incomplete Letters, Silhouettes, Object Decision, and Progressive Silhouettes) while the other 4 measure visual space perception (Dot Counting, Position Discrimination, Number Location, and Cube Analysis). The statistical procedures employed were either simple or multiple linear regression analyses (subtests with normal distribution) and Mann-Whitney tests, followed by ANOVA with Scheffe correction (subtests without normal distribution). Age and sex were found to be significant modifying factors in the Silhouettes, Object Decision, Progressive Silhouettes, Position Discrimination, and Cube Analysis subtests. Educational level was found to be a significant predictor of function for the Silhouettes and Object Decision subtests. The results of the sample were adjusted in line with the differences observed. Our study also offers preliminary normative data for the administration of the VOSP to an elderly Spanish population. The results are discussed and compared with similar studies performed in different cultural backgrounds.

Improved US visualization of the pancreatic tail with simethicone, water, and patient rotation.

PubMed

Abu-Yousef, M M; El-Zein, Y

2000-12-01

To evaluate the effect of degassed water, simethicone, and patient rotation on ultrasonographic (US) visualization of the pancreatic tail. Seventy patients in whom visualization of the pancreatic tail was poor at US were reevaluated in the upright position after ingesting 2 cups (500 mL) of water with 80 mg of simethicone followed by rotating three times on the examination table. In a few patients, the right posterior oblique position was used. Pancreatic tail visualization and disbursement of gastric gas were evaluated. Seventy patients who received 500 mL of distilled water only served as control subjects. Pancreatic tail visualization in patients versus control subjects was complete in 55 (79%) versus five (7%) of 70 patients and control subjects, partial in 10 (14%) versus 38 (54%), and not improved in five (7%) versus 27 (39%). The effect on diminishing gastric air was closely correlated with the degree of improved visualization in most patients. All patients tolerated the procedure well, with no side effects. The technique added a mean of 8 versus 5 minutes to the examination in patients versus control subjects. The full acoustic window effect of the simethicone-water mixture lasted approximately 10 minutes. The simethicone-water-rotation technique is simple, safe, inexpensive, and effective for improving pancreatic tail visualization in ambulatory patients and is superior to the use of water alone.

Development of a statistical method to help evaluating the transparency/opacity of decorative thin films

NASA Astrophysics Data System (ADS)

da Silva Oliveira, C. I.; Martinez-Martinez, D.; Al-Rjoub, A.; Rebouta, L.; Menezes, R.; Cunha, L.

2018-04-01

In this paper, we present a statistical method that allows evaluating the degree of a transparency of a thin film. To do so, the color coordinates are measured on different substrates, and the standard deviation is evaluated. In case of low values, the color depends on the film and not on the substrate, and intrinsic colors are obtained. In contrast, transparent films lead to high values of standard deviation, since the value of the color coordinates depends on the substrate. Between both extremes, colored films with a certain degree of transparency can be found. This method allows an objective and simple evaluation of the transparency of any film, improving the subjective visual inspection and avoiding the thickness problems related to optical spectroscopy evaluation. Zirconium oxynitride films deposited on three different substrates (Si, steel and glass) are used for testing the validity of this method, whose results have been validated with optical spectroscopy, and agree with the visual impression of the samples.

Student Satisfaction With Blackboard-Style Videos.

PubMed

Wolf, Andrew B; Peyre, Sarah E

2018-04-19

Blackboard-style videos with simple drawings illustrating concepts have become immensely popular in recent years. However, there has been no published research evaluating their efficacy in nursing education. This pilot study evaluates the use of blackboard-style videos in an online pathophysiology course. Quantitative and qualitative evaluation data were analyzed to evaluate student satisfaction. The data indicated that students were highly satisfied with the course and the delivery of content using blackboard-style videos. The qualitative analysis uncovered two key themes explaining the high level of satisfaction: visual plus narrative explanations support learning and student control over pacing enhances learning.

Simple Learned Weighted Sums of Inferior Temporal Neuronal Firing Rates Accurately Predict Human Core Object Recognition Performance

PubMed Central

Hong, Ha; Solomon, Ethan A.; DiCarlo, James J.

2015-01-01

To go beyond qualitative models of the biological substrate of object recognition, we ask: can a single ventral stream neuronal linking hypothesis quantitatively account for core object recognition performance over a broad range of tasks? We measured human performance in 64 object recognition tests using thousands of challenging images that explore shape similarity and identity preserving object variation. We then used multielectrode arrays to measure neuronal population responses to those same images in visual areas V4 and inferior temporal (IT) cortex of monkeys and simulated V1 population responses. We tested leading candidate linking hypotheses and control hypotheses, each postulating how ventral stream neuronal responses underlie object recognition behavior. Specifically, for each hypothesis, we computed the predicted performance on the 64 tests and compared it with the measured pattern of human performance. All tested hypotheses based on low- and mid-level visually evoked activity (pixels, V1, and V4) were very poor predictors of the human behavioral pattern. However, simple learned weighted sums of distributed average IT firing rates exactly predicted the behavioral pattern. More elaborate linking hypotheses relying on IT trial-by-trial correlational structure, finer IT temporal codes, or ones that strictly respect the known spatial substructures of IT (“face patches”) did not improve predictive power. Although these results do not reject those more elaborate hypotheses, they suggest a simple, sufficient quantitative model: each object recognition task is learned from the spatially distributed mean firing rates (100 ms) of ∼60,000 IT neurons and is executed as a simple weighted sum of those firing rates. SIGNIFICANCE STATEMENT We sought to go beyond qualitative models of visual object recognition and determine whether a single neuronal linking hypothesis can quantitatively account for core object recognition behavior. To achieve this, we designed a database of images for evaluating object recognition performance. We used multielectrode arrays to characterize hundreds of neurons in the visual ventral stream of nonhuman primates and measured the object recognition performance of >100 human observers. Remarkably, we found that simple learned weighted sums of firing rates of neurons in monkey inferior temporal (IT) cortex accurately predicted human performance. Although previous work led us to expect that IT would outperform V4, we were surprised by the quantitative precision with which simple IT-based linking hypotheses accounted for human behavior. PMID:26424887

Acoustic Tactile Representation of Visual Information

NASA Astrophysics Data System (ADS)

Silva, Pubudu Madhawa

Our goal is to explore the use of hearing and touch to convey graphical and pictorial information to visually impaired people. Our focus is on dynamic, interactive display of visual information using existing, widely available devices, such as smart phones and tablets with touch sensitive screens. We propose a new approach for acoustic-tactile representation of visual signals that can be implemented on a touch screen and allows the user to actively explore a two-dimensional layout consisting of one or more objects with a finger or a stylus while listening to auditory feedback via stereo headphones. The proposed approach is acoustic-tactile because sound is used as the primary source of information for object localization and identification, while touch is used for pointing and kinesthetic feedback. A static overlay of raised-dot tactile patterns can also be added. A key distinguishing feature of the proposed approach is the use of spatial sound (directional and distance cues) to facilitate the active exploration of the layout. We consider a variety of configurations for acoustic-tactile rendering of object size, shape, identity, and location, as well as for the overall perception of simple layouts and scenes. While our primary goal is to explore the fundamental capabilities and limitations of representing visual information in acoustic-tactile form, we also consider a number of relatively simple configurations that can be tied to specific applications. In particular, we consider a simple scene layout consisting of objects in a linear arrangement, each with a distinct tapping sound, which we compare to a ''virtual cane.'' We will also present a configuration that can convey a ''Venn diagram.'' We present systematic subjective experiments to evaluate the effectiveness of the proposed display for shape perception, object identification and localization, and 2-D layout perception, as well as the applications. Our experiments were conducted with visually blocked subjects. The results are evaluated in terms of accuracy and speed, and they demonstrate the advantages of spatial sound for guiding the scanning finger or pointer in shape perception, object localization, and layout exploration. We show that these advantages increase with the amount of detail (smaller object size) in the display. Our experimental results show that the proposed system outperforms the state of the art in shape perception, including variable friction displays. We also demonstrate that, even though they are currently available only as static overlays, raised dot patterns provide the best shape rendition in terms of both the accuracy and speed. Our experiments with layout rendering and perception demonstrate that simultaneous representation of objects, using the most effective approaches for directionality and distance rendering, approaches the optimal performance level provided by visual layout perception. Finally, experiments with the virtual cane and Venn diagram configurations demonstrate that the proposed techniques can be used effectively in simple but nontrivial real-world applications. One of the most important conclusions of our experiments is that there is a clear performance gap between experienced and inexperienced subjects, which indicates that there is a lot of room for improvement with appropriate and extensive training. By exploring a wide variety of design alternatives and focusing on different aspects of the acoustic-tactile interfaces, our results offer many valuable insights and great promise for the design of future systematic tests visually impaired and visually blocked subjects, utilizing the most effective configurations.

Are children with low vision adapted to the visual environment in classrooms of mainstream schools?

PubMed

Negiloni, Kalpa; Ramani, Krishna Kumar; Jeevitha, R; Kalva, Jayashree; Sudhir, Rachapalle Reddi

2018-02-01

The study aimed to evaluate the classroom environment of children with low vision and provide recommendations to reduce visual stress, with focus on mainstream schooling. The medical records of 110 children (5-17 years) seen in low vision clinic during 1 year period (2015) at a tertiary care center in south India were extracted. The visual function levels of children were compared to the details of their classroom environment. The study evaluated and recommended the chalkboard visual task size and viewing distance required for children with mild, moderate, and severe visual impairment (VI). The major causes of low vision based on the site of abnormality and etiology were retinal (80%) and hereditary (67%) conditions, respectively, in children with mild (n = 18), moderate (n = 72), and severe (n = 20) VI. Many of the children (72%) had difficulty in viewing chalkboard and common strategies used for better visibility included copying from friends (47%) and going closer to chalkboard (42%). To view the chalkboard with reduced visual stress, a child with mild VI can be seated at a maximum distance of 4.3 m from the chalkboard, with the minimum size of visual task (height of lowercase letter writing on chalkboard) recommended to be 3 cm. For 3/60-6/60 range, the maximum viewing distance with the visual task size of 4 cm is recommended to be 85 cm to 1.7 m. Simple modifications of the visual task size and seating arrangements can aid children with low vision with better visibility of chalkboard and reduced visual stress to manage in mainstream schools.

Issues in Combining the Use of Various Tools in Solving Mathematical Problems--Why Is Copy-Paste Often Useless

ERIC Educational Resources Information Center

Lokar, Matija; Libbrecht, Paul

2017-01-01

Mathematical formulae are information objects that can be entered in a computer, visualized, and evaluated. Thus, by the majority of (mostly occasional) users it is also expected that they are transferable through the simple copy-paste procedure. This transfer is particularly interesting when users are involved in tasks that span different…

Colorimetric detection of Cucumber green mottle mosaic virus using unmodified gold nanoparticles as colorimetric probes.

PubMed

Wang, Lin; Liu, Zhanmin; Xia, Xueying; Yang, Cuiyun; Huang, Junyi; Wan, Sibao

2017-05-01

Cucumber green mottle mosaic virus (CGMMV)causes a severe mosaic symptom of watermelon and cucumber, and can be transmitted via infected cucumber seeds, leaves and soil. It remains a challenge to detect this virus to prevent its introduction and infection and spread in fields. For this purpose, a simple and sensitive label-free colorimetric detection method for CGMMV has been developed with unmodified gold nanoparticles (AuNPs) as colorimetric probes. The method is based on the finding that the presence of RT-PCR target products of CGMMV and species-specific probes results in color change of AuNPs from red to blue after NaCl induction. Normally, species-specific probes attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. The concentration of sodium, probes in the reaction system and evaluation of specificity and sensitivity of a novel assay, visual detection of Cucumber green mottle mosaic virus using unmodified AuNPs has been carried out with simple preparation of samples in our study. Through this assay, as low as 30pg/μL of CGMMV RNA was thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents. The specificity was 100% and exhibited good reproducibility in our assays. The results note that this assay is highly species-specific, simple, low-cost, and visual for easy detection of CGMMV in plant tissues. Therefore, visual assay is a potentially useful tool for middle or small-scales corporations and entry-exit inspection and quarantine bureau to detect CGMMV in cucumber seeds or plant tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

Combined Special Capsular Tension Ring and Toric IOL Implantation for Management of Astigmatism and High Axial Myopia with Cataracts.

PubMed

Zhao, Yang; Li, Jiaxin; Yang, Ke; Li, Xiao; Zhu, Siquan

2018-01-01

This study aimed to compare the effects of toric intraocular lens (IOL) implantation with a capsular tension ring and toric IOL implantation only in patients with axial myopic astigmatism who had undergone cataract surgery. Of 34 patients with axial myopia, 16 patients who had received IOL and capsular tension ring (CTR) implantation were included in the combined group and 18 patients who received toric IOL implantation only were included in the simple group. Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) were evaluated by measuring subjective refraction, residual astigmatism, and the toric IOL axis six months post-surgery. At six months postoperatively, the UCVA for the combined and simple groups was 4.6 ± 0.1 and 4.5 ± 0.2, respectively, a statistically significant difference (t = 3.531, P<0.05). The toric IOL in all of the cases was located in the capsular sac, but there were more cases with IOL rotation (12 eyes) in the simple group than in the combined group (4 eyes). The rotation angles were 20°~30° (one eye), 10°~20° (four eyes), and <10° (seven eyes) compared with 2°~5° (four eyes). The residual astigmatism was -0.50 ± 0.25 D in the combined group, not a significant difference from the predicted residual astigmatism (-0.35 ± 0.13 D). There was a significant difference in the simple group (-1.25 ± 0.33 D) when the predicted residual astigmatism was compared (-0.37 ± 0.11 D) (t = -9.511, P < 0.01). In patients with axial myopic astigmatism, CTR can effectively increase the rotational stability of a toric IOL, achieving improvement in corneal astigmatism and visual acuity.

Simple Psychological Interventions for Reducing Pain From Common Needle Procedures in Adults

PubMed Central

Boerner, Katelynn E.; Birnie, Kathryn A.; Taddio, Anna; McMurtry, C. Meghan; Noel, Melanie; Shah, Vibhuti; Pillai Riddell, Rebecca

2015-01-01

Background: This systematic review evaluated the effectiveness of simple psychological interventions for managing pain and fear in adults undergoing vaccination or related common needle procedures (ie, venipuncture/venous cannulation). Design/Methods: Databases were searched to identify relevant randomized and quasi-randomized controlled trials. Self-reported pain and fear were prioritized as critically important outcomes. Data were combined using standardized mean difference (SMD) or relative risk (RR) with 95% confidence intervals (CI). Results: No studies involving vaccination met inclusion criteria; evidence was drawn from 8 studies of other common needle procedures (eg, venous cannulation, venipuncture) in adults. Two trials evaluating the impact of neutral signaling of the impending procedure (eg, “ready?”) as compared with signaling of impending pain (eg, “sharp scratch”) demonstrated lower pain when signaled about the procedure (n=199): SMD=−0.97 (95% CI, −1.26, −0.68), after removal of 1 trial where self-reported pain was significantly lower than the other 2 included trials. Two trials evaluated music distraction (n=156) and demonstrated no difference in pain: SMD=0.10 (95% CI, −0.48, 0.27), or fear: SMD=−0.25 (95% CI, −0.61, 0.10). Two trials evaluated visual distraction and demonstrated no difference in pain (n=177): SMD=−0.57 (95% CI, −1.82, 0.68), or fear (n=81): SMD=−0.05 (95% CI, −0.50, 0.40). Two trials evaluating breathing interventions found less pain in intervention groups (n=138): SMD=−0.82 (95% CI, −1.21, −0.43). The quality of evidence across all trials was very low. Conclusions: There are no published studies of simple psychological interventions for vaccination pain in adults. There is some evidence of a benefit from other needle procedures for breathing strategies and neutral signaling of the start of the procedure. There is no evidence for use of music or visual distraction. PMID:26352921

An egalitarian network model for the emergence of simple and complex cells in visual cortex

PubMed Central

Tao, Louis; Shelley, Michael; McLaughlin, David; Shapley, Robert

2004-01-01

We explain how simple and complex cells arise in a large-scale neuronal network model of the primary visual cortex of the macaque. Our model consists of ≈4,000 integrate-and-fire, conductance-based point neurons, representing the cells in a small, 1-mm2 patch of an input layer of the primary visual cortex. In the model the local connections are isotropic and nonspecific, and convergent input from the lateral geniculate nucleus confers cortical cells with orientation and spatial phase preference. The balance between lateral connections and lateral geniculate nucleus drive determines whether individual neurons in this recurrent circuit are simple or complex. The model reproduces qualitatively the experimentally observed distributions of both extracellular and intracellular measures of simple and complex response. PMID:14695891

Improved CORF model of simple cell combined with non-classical receptive field and its application on edge detection

NASA Astrophysics Data System (ADS)

Sun, Xiao; Chai, Guobei; Liu, Wei; Bao, Wenzhuo; Zhao, Xiaoning; Ming, Delie

2018-02-01

Simple cells in primary visual cortex are believed to extract local edge information from a visual scene. In this paper, inspired by different receptive field properties and visual information flow paths of neurons, an improved Combination of Receptive Fields (CORF) model combined with non-classical receptive fields was proposed to simulate the responses of simple cell's receptive fields. Compared to the classical model, the proposed model is able to better imitate simple cell's physiologic structure with consideration of facilitation and suppression of non-classical receptive fields. And on this base, an edge detection algorithm as an application of the improved CORF model was proposed. Experimental results validate the robustness of the proposed algorithm to noise and background interference.

Accurate analysis and visualization of cardiac (11)C-PIB uptake in amyloidosis with semiautomatic software.

PubMed

Kero, Tanja; Lindsjö, Lars; Sörensen, Jens; Lubberink, Mark

2016-08-01

(11)C-PIB PET is a promising non-invasive diagnostic tool for cardiac amyloidosis. Semiautomatic analysis of PET data is now available but it is not known how accurate these methods are for amyloid imaging. The aim of this study was to evaluate the feasibility of one semiautomatic software tool for analysis and visualization of (11)C-PIB left ventricular retention index (RI) in cardiac amyloidosis. Patients with systemic amyloidosis and cardiac involvement (n = 10) and healthy controls (n = 5) were investigated with dynamic (11)C-PIB PET. Two observers analyzed the PET studies with semiautomatic software to calculate the left ventricular RI of (11)C-PIB and to create parametric images. The mean RI at 15-25 min from the semiautomatic analysis was compared with RI based on manual analysis and showed comparable values (0.056 vs 0.054 min(-1) for amyloidosis patients and 0.024 vs 0.025 min(-1) in healthy controls; P = .78) and the correlation was excellent (r = 0.98). Inter-reader reproducibility also was excellent (intraclass correlation coefficient, ICC > 0.98). Parametric polarmaps and histograms made visual separation of amyloidosis patients and healthy controls fast and simple. Accurate semiautomatic analysis of cardiac (11)C-PIB RI in amyloidosis patients is feasible. Parametric polarmaps and histograms make visual interpretation fast and simple.

Use of papain gel in disabled patients.

PubMed

Carrillo, C M; Tanaka, M H; Cesar, M F; Camargo, M A F; Juliano, Y; Novo, N F

2008-01-01

This study's purpose was to evaluate complete caries removal time (CCR) and patient acceptance of the chemomechanical caries removal agent and papain gel Papacárie in disabled patients. Fifty-one consecutive patients entered a prospective, controlled, randomized, open study. Patients were divided into 2 groups: (1) group 1=28 children 3 to 10 years old with or without visual or hearing impairments, motor disability on upper limbs, and inability to respond to simple orders; and (2) group 2=23 children, without visual or hearing impairments, with motor disability on the upper limbs and the ability to respond to simple orders. CCR time was measured in both groups. Patients' acceptance was assessed only in group 2 by using the visual analogy of face scale. The visual scale was presented in phase A--after the radiography with the child sitting on the dental chair before the beginning of the treatment, phase B--during the treatment, after total removal of the carious tissue and phase C--after the restoration was complete (treatment was finished). The total CCR average time was 8 minutes for each tooth when groups 1 and 2 were considered. Group 2 patients' acceptance in the first treatment was not statistically significant in all stages. Papacárie gel had a completed caries removal time of 8 minutes per tooth and is well accepted by the patients in all phases and in the first and subsequent visits.

Combining local and global limitations of visual search.

PubMed

Põder, Endel

2017-04-01

There are different opinions about the roles of local interactions and central processing capacity in visual search. This study attempts to clarify the problem using a new version of relevant set cueing. A central precue indicates two symmetrical segments (that may contain a target object) within a circular array of objects presented briefly around the fixation point. The number of objects in the relevant segments, and density of objects in the array were varied independently. Three types of search experiments were run: (a) search for a simple visual feature (color, size, and orientation); (b) conjunctions of simple features; and (c) spatial configuration of simple features (rotated Ts). For spatial configuration stimuli, the results were consistent with a fixed global processing capacity and standard crowding zones. For simple features and their conjunctions, the results were different, dependent on the features involved. While color search exhibits virtually no capacity limits or crowding, search for an orientation target was limited by both. Results for conjunctions of features can be partly explained by the results from the respective features. This study shows that visual search is limited by both local interference and global capacity, and the limitations are different for different visual features.

A Simple Model of Hox Genes: Bone Morphology Demonstration

ERIC Educational Resources Information Center

Shmaefsky, Brian

2008-01-01

Visual demonstrations of abstract scientific concepts are effective strategies for enhancing content retention (Shmaefsky 2004). The concepts associated with gene regulation of growth and development are particularly complex and are well suited for teaching with visual models. This demonstration provides a simple and accurate model of Hox gene…

Are children with low vision adapted to the visual environment in classrooms of mainstream schools?

PubMed Central

Negiloni, Kalpa; Ramani, Krishna Kumar; Jeevitha, R; Kalva, Jayashree; Sudhir, Rachapalle Reddi

2018-01-01

Purpose: The study aimed to evaluate the classroom environment of children with low vision and provide recommendations to reduce visual stress, with focus on mainstream schooling. Methods: The medical records of 110 children (5–17 years) seen in low vision clinic during 1 year period (2015) at a tertiary care center in south India were extracted. The visual function levels of children were compared to the details of their classroom environment. The study evaluated and recommended the chalkboard visual task size and viewing distance required for children with mild, moderate, and severe visual impairment (VI). Results: The major causes of low vision based on the site of abnormality and etiology were retinal (80%) and hereditary (67%) conditions, respectively, in children with mild (n = 18), moderate (n = 72), and severe (n = 20) VI. Many of the children (72%) had difficulty in viewing chalkboard and common strategies used for better visibility included copying from friends (47%) and going closer to chalkboard (42%). To view the chalkboard with reduced visual stress, a child with mild VI can be seated at a maximum distance of 4.3 m from the chalkboard, with the minimum size of visual task (height of lowercase letter writing on chalkboard) recommended to be 3 cm. For 3/60–6/60 range, the maximum viewing distance with the visual task size of 4 cm is recommended to be 85 cm to 1.7 m. Conclusion: Simple modifications of the visual task size and seating arrangements can aid children with low vision with better visibility of chalkboard and reduced visual stress to manage in mainstream schools. PMID:29380777

Consumer visual appraisal and shelf life of leg chops from suckling kids raised with natural milk or milk replacer.

PubMed

Ripoll, Guillermo; Alcalde, María J; Argüello, Anastasio; Córdoba, María G; Panea, Begoña

2018-05-01

The use of milk replacers to feed suckling kids could affect the shelf life and appearance of the meat. Leg chops were evaluated by consumers and the instrumental color was measured. A machine learning algorithm was used to relate them. The aim of this experiment was to study the shelf life of the meat of kids reared with dam's milk or milk replacers and to ascertain which illuminant and instrumental color variables are used by consumers as criteria to evaluate that visual appraisal. Meat from kids reared with milk replacers was more valuable and had a longer shelf life than meat from kids reared with natural milk. Consumers used the color of the whole surface of the leg chop to assess the appearance of meat. Lightness and hue angle were the prime cues used to evaluate the appearance of meat. Illuminant D65 was more useful for relating the visual appraisal with the instrumental color using a machine learning algorithm. The machine learning algorithms showed that the underlying rules used by consumers to evaluate the appearance of suckling kid meat are not at all linear and can be computationally schematized into a simple algorithm. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Simple Learned Weighted Sums of Inferior Temporal Neuronal Firing Rates Accurately Predict Human Core Object Recognition Performance.

PubMed

Majaj, Najib J; Hong, Ha; Solomon, Ethan A; DiCarlo, James J

2015-09-30

To go beyond qualitative models of the biological substrate of object recognition, we ask: can a single ventral stream neuronal linking hypothesis quantitatively account for core object recognition performance over a broad range of tasks? We measured human performance in 64 object recognition tests using thousands of challenging images that explore shape similarity and identity preserving object variation. We then used multielectrode arrays to measure neuronal population responses to those same images in visual areas V4 and inferior temporal (IT) cortex of monkeys and simulated V1 population responses. We tested leading candidate linking hypotheses and control hypotheses, each postulating how ventral stream neuronal responses underlie object recognition behavior. Specifically, for each hypothesis, we computed the predicted performance on the 64 tests and compared it with the measured pattern of human performance. All tested hypotheses based on low- and mid-level visually evoked activity (pixels, V1, and V4) were very poor predictors of the human behavioral pattern. However, simple learned weighted sums of distributed average IT firing rates exactly predicted the behavioral pattern. More elaborate linking hypotheses relying on IT trial-by-trial correlational structure, finer IT temporal codes, or ones that strictly respect the known spatial substructures of IT ("face patches") did not improve predictive power. Although these results do not reject those more elaborate hypotheses, they suggest a simple, sufficient quantitative model: each object recognition task is learned from the spatially distributed mean firing rates (100 ms) of ∼60,000 IT neurons and is executed as a simple weighted sum of those firing rates. Significance statement: We sought to go beyond qualitative models of visual object recognition and determine whether a single neuronal linking hypothesis can quantitatively account for core object recognition behavior. To achieve this, we designed a database of images for evaluating object recognition performance. We used multielectrode arrays to characterize hundreds of neurons in the visual ventral stream of nonhuman primates and measured the object recognition performance of >100 human observers. Remarkably, we found that simple learned weighted sums of firing rates of neurons in monkey inferior temporal (IT) cortex accurately predicted human performance. Although previous work led us to expect that IT would outperform V4, we were surprised by the quantitative precision with which simple IT-based linking hypotheses accounted for human behavior. Copyright © 2015 the authors 0270-6474/15/3513402-17$15.00/0.

Central Visual Prosthesis With Interface at the Lateral Geniculate Nucleus

DTIC Science & Technology

2017-07-01

burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching...currently used in the field to implant Deep Brain Stimulation electrodes. Page 4 We thus limited ourselves to using a ‘4 French’ size split sheath...this program. At this time , several approaches for realizing the complete system have been evaluated. Initially, a very simple mechanical mockup

Are V1 Simple Cells Optimized for Visual Occlusions? A Comparative Study

PubMed Central

Bornschein, Jörg; Henniges, Marc; Lücke, Jörg

2013-01-01

Simple cells in primary visual cortex were famously found to respond to low-level image components such as edges. Sparse coding and independent component analysis (ICA) emerged as the standard computational models for simple cell coding because they linked their receptive fields to the statistics of visual stimuli. However, a salient feature of image statistics, occlusions of image components, is not considered by these models. Here we ask if occlusions have an effect on the predicted shapes of simple cell receptive fields. We use a comparative approach to answer this question and investigate two models for simple cells: a standard linear model and an occlusive model. For both models we simultaneously estimate optimal receptive fields, sparsity and stimulus noise. The two models are identical except for their component superposition assumption. We find the image encoding and receptive fields predicted by the models to differ significantly. While both models predict many Gabor-like fields, the occlusive model predicts a much sparser encoding and high percentages of ‘globular’ receptive fields. This relatively new center-surround type of simple cell response is observed since reverse correlation is used in experimental studies. While high percentages of ‘globular’ fields can be obtained using specific choices of sparsity and overcompleteness in linear sparse coding, no or only low proportions are reported in the vast majority of studies on linear models (including all ICA models). Likewise, for the here investigated linear model and optimal sparsity, only low proportions of ‘globular’ fields are observed. In comparison, the occlusive model robustly infers high proportions and can match the experimentally observed high proportions of ‘globular’ fields well. Our computational study, therefore, suggests that ‘globular’ fields may be evidence for an optimal encoding of visual occlusions in primary visual cortex. PMID:23754938

A Randomized Study Comparing the Sniffing Position with Simple Head Extension for Glottis Visualization and Difficulty in Intubation during Direct Laryngoscopy.

PubMed

Akhtar, Mehmooda; Ali, Zulfiqar; Hassan, Nelofar; Mehdi, Saqib; Wani, Gh Mohammad; Mir, Aabid Hussain

2017-01-01

Proper positioning of the head and neck is important for an optimal laryngeal visualization. Traditionally, sniffing position (SP) is recommended to provide a superior glottic visualization, during direct laryngoscopy, enhancing the ease of intubation. Various studies in the last decade of this belief have challenged the need for sniffing position during intubation. We conducted a prospective study comparing the sniffing head position with simple head extension to study the laryngoscopic view and intubation difficulty during direct laryngoscopy. Five-hundred patients were included in this study and randomly distributed to SP or simple head extension. In the sniffing group, an incompressible head ring was placed under the head to raise its height by 7 cm from the neutral plane followed by maximal extension of the head. In the simple extension group, no headrest was placed under the head; however, maximal head extension was given at the time of laryngoscopy. Various factors as ability to mask ventilate, laryngoscopic visualization, intubation difficulty, and posture of the anesthesiologist during laryngoscopy and tracheal intubation were noted. In the incidence of difficult laryngoscopy (Cormack Grade III and IV), Intubation Difficulty Scale (IDS score) was compared between the two groups. There was no significant difference between two groups in Cormack grades. The IDS score differed significantly between sniffing group and simple extension group ( P = 0.000) with an increased difficulty during intubation in the simple head extension. Patients with simple head extension needed more lifting force, increased use of external laryngeal manipulation, and an increased use of alternate techniques during intubation when compared to SP. We conclude that compared to the simple head extension position, the SP should be used as a standard head position for intubation attempts under general anesthesia.

Memory colours and colour quality evaluation of conventional and solid-state lamps.

PubMed

Smet, Kevin A G; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

2010-12-06

A colour quality metric based on memory colours is presented. The basic idea is simple. The colour quality of a test source is evaluated as the degree of similarity between the colour appearance of a set of familiar objects and their memory colours. The closer the match, the better the colour quality. This similarity was quantified using a set of similarity distributions obtained by Smet et al. in a previous study. The metric was validated by calculating the Pearson and Spearman correlation coefficients between the metric predictions and the visual appreciation results obtained in a validation experiment conducted by the authors as well those obtained in two independent studies. The metric was found to correlate well with the visual appreciation of the lighting quality of the sources used in the three experiments. Its performance was also compared with that of the CIE colour rendering index and the NIST colour quality scale. For all three experiments, the metric was found to be significantly better at predicting the correct visual rank order of the light sources (p < 0.1).

Predicting successful tactile mapping of virtual objects.

PubMed

Brayda, Luca; Campus, Claudio; Gori, Monica

2013-01-01

Improving spatial ability of blind and visually impaired people is the main target of orientation and mobility (O&M) programs. In this study, we use a minimalistic mouse-shaped haptic device to show a new approach aimed at evaluating devices providing tactile representations of virtual objects. We consider psychophysical, behavioral, and subjective parameters to clarify under which circumstances mental representations of spaces (cognitive maps) can be efficiently constructed with touch by blindfolded sighted subjects. We study two complementary processes that determine map construction: low-level perception (in a passive stimulation task) and high-level information integration (in an active exploration task). We show that jointly considering a behavioral measure of information acquisition and a subjective measure of cognitive load can give an accurate prediction and a practical interpretation of mapping performance. Our simple TActile MOuse (TAMO) uses haptics to assess spatial ability: this may help individuals who are blind or visually impaired to be better evaluated by O&M practitioners or to evaluate their own performance.

Indocyanine green fluorescence imaging in hepatobiliary surgery.

PubMed

Majlesara, Ali; Golriz, Mohammad; Hafezi, Mohammadreza; Saffari, Arash; Stenau, Esther; Maier-Hein, Lena; Müller-Stich, Beat P; Mehrabi, Arianeb

2017-03-01

Indocyanine green (ICG) is a fluorescent dye that has been widely used for fluorescence imaging during hepatobiliary surgery. ICG is injected intravenously, selectively taken up by the liver, and then secreted into the bile. The catabolism and fluorescence properties of ICG permit a wide range of visualization methods in hepatobiliary surgery. We have characterized the applications of ICG during hepatobiliary surgery into: 1) liver mapping, 2) cholangiography, 3) tumor visualization, and 4) partial liver graft evaluation. In this literature review, we summarize the current understanding of ICG use during hepatobiliary surgery. Intra-operative ICG fluorescence imaging is a safe, simple, and feasible method that improves the visualization of hepatobiliary anatomy and liver tumors. Intravenous administration of ICG is not toxic and avoids the drawbacks of conventional imaging. In addition, it reduces post-operative complications without any known side effects. ICG fluorescence imaging provides a safe and reliable contrast for extra-hepatic cholangiography when detecting intra-hepatic bile leakage following liver resection. In addition, liver tumors can be visualized and well-differentiated hepatocellular carcinoma tumors can be accurately identified. Moreover, vascular reconstruction and outflow can be evaluated following partial liver transplantation. However, since tissue penetration is limited to 5-10mm, deeper tissue cannot be visualized using this method. Many instances of false positive or negative results have been reported, therefore further characterization is required. Copyright © 2016 Elsevier B.V. All rights reserved.

An effective visualization technique for depth perception in augmented reality-based surgical navigation.

PubMed

Choi, Hyunseok; Cho, Byunghyun; Masamune, Ken; Hashizume, Makoto; Hong, Jaesung

2016-03-01

Depth perception is a major issue in augmented reality (AR)-based surgical navigation. We propose an AR and virtual reality (VR) switchable visualization system with distance information, and evaluate its performance in a surgical navigation set-up. To improve depth perception, seamless switching from AR to VR was implemented. In addition, the minimum distance between the tip of the surgical tool and the nearest organ was provided in real time. To evaluate the proposed techniques, five physicians and 20 non-medical volunteers participated in experiments. Targeting error, time taken, and numbers of collisions were measured in simulation experiments. There was a statistically significant difference between a simple AR technique and the proposed technique. We confirmed that depth perception in AR could be improved by the proposed seamless switching between AR and VR, and providing an indication of the minimum distance also facilitated the surgical tasks. Copyright © 2015 John Wiley & Sons, Ltd.

Simple and Sensitive Paper-Based Device Coupling Electrochemical Sample Pretreatment and Colorimetric Detection.

PubMed

Silva, Thalita G; de Araujo, William R; Muñoz, Rodrigo A A; Richter, Eduardo M; Santana, Mário H P; Coltro, Wendell K T; Paixão, Thiago R L C

2016-05-17

We report the development of a simple, portable, low-cost, high-throughput visual colorimetric paper-based analytical device for the detection of procaine in seized cocaine samples. The interference of most common cutting agents found in cocaine samples was verified, and a novel electrochemical approach was used for sample pretreatment in order to increase the selectivity. Under the optimized experimental conditions, a linear analytical curve was obtained for procaine concentrations ranging from 5 to 60 μmol L(-1), with a detection limit of 0.9 μmol L(-1). The accuracy of the proposed method was evaluated using seized cocaine samples and an addition and recovery protocol.

Beyond simple charts: Design of visualizations for big health data

PubMed Central

Ola, Oluwakemi; Sedig, Kamran

2016-01-01

Health data is often big data due to its high volume, low veracity, great variety, and high velocity. Big health data has the potential to improve productivity, eliminate waste, and support a broad range of tasks related to disease surveillance, patient care, research, and population health management. Interactive visualizations have the potential to amplify big data’s utilization. Visualizations can be used to support a variety of tasks, such as tracking the geographic distribution of diseases, analyzing the prevalence of disease, triaging medical records, predicting outbreaks, and discovering at-risk populations. Currently, many health visualization tools use simple charts, such as bar charts and scatter plots, that only represent few facets of data. These tools, while beneficial for simple perceptual and cognitive tasks, are ineffective when dealing with more complex sensemaking tasks that involve exploration of various facets and elements of big data simultaneously. There is need for sophisticated and elaborate visualizations that encode many facets of data and support human-data interaction with big data and more complex tasks. When not approached systematically, design of such visualizations is labor-intensive, and the resulting designs may not facilitate big-data-driven tasks. Conceptual frameworks that guide the design of visualizations for big data can make the design process more manageable and result in more effective visualizations. In this paper, we demonstrate how a framework-based approach can help designers create novel, elaborate, non-trivial visualizations for big health data. We present four visualizations that are components of a larger tool for making sense of large-scale public health data. PMID:28210416

Beyond simple charts: Design of visualizations for big health data.

PubMed

Ola, Oluwakemi; Sedig, Kamran

2016-01-01

Health data is often big data due to its high volume, low veracity, great variety, and high velocity. Big health data has the potential to improve productivity, eliminate waste, and support a broad range of tasks related to disease surveillance, patient care, research, and population health management. Interactive visualizations have the potential to amplify big data's utilization. Visualizations can be used to support a variety of tasks, such as tracking the geographic distribution of diseases, analyzing the prevalence of disease, triaging medical records, predicting outbreaks, and discovering at-risk populations. Currently, many health visualization tools use simple charts, such as bar charts and scatter plots, that only represent few facets of data. These tools, while beneficial for simple perceptual and cognitive tasks, are ineffective when dealing with more complex sensemaking tasks that involve exploration of various facets and elements of big data simultaneously. There is need for sophisticated and elaborate visualizations that encode many facets of data and support human-data interaction with big data and more complex tasks. When not approached systematically, design of such visualizations is labor-intensive, and the resulting designs may not facilitate big-data-driven tasks. Conceptual frameworks that guide the design of visualizations for big data can make the design process more manageable and result in more effective visualizations. In this paper, we demonstrate how a framework-based approach can help designers create novel, elaborate, non-trivial visualizations for big health data. We present four visualizations that are components of a larger tool for making sense of large-scale public health data.

Black–white asymmetry in visual perception

PubMed Central

Lu, Zhong-Lin; Sperling, George

2012-01-01

With eleven different types of stimuli that exercise a wide gamut of spatial and temporal visual processes, negative perturbations from mean luminance are found to be typically 25% more effective visually than positive perturbations of the same magnitude (range 8–67%). In Experiment 12, the magnitude of the black–white asymmetry is shown to be a saturating function of stimulus contrast. Experiment 13 shows black–white asymmetry primarily involves a nonlinearity in the visual representation of decrements. Black–white asymmetry in early visual processing produces even-harmonic distortion frequencies in all ordinary stimuli and in illusions such as the perceived asymmetry of optically perfect sine wave gratings. In stimuli intended to stimulate exclusively second-order processing in which motion or shape are defined not by luminance differences but by differences in texture contrast, the black–white asymmetry typically generates artifactual luminance (first-order) motion and shape components. Because black–white asymmetry pervades psychophysical and neurophysiological procedures that utilize spatial or temporal variations of luminance, it frequently needs to be considered in the design and evaluation of experiments that involve visual stimuli. Simple procedures to compensate for black–white asymmetry are proposed. PMID:22984221

Simple and powerful visual stimulus generator.

PubMed

Kremlácek, J; Kuba, M; Kubová, Z; Vít, F

1999-02-01

We describe a cheap, simple, portable and efficient approach to visual stimulation for neurophysiology which does not need any special hardware equipment. The method based on an animation technique uses the FLI autodesk animator format. This form of the animation is replayed by a special program ('player') providing synchronisation pulses toward recording system via parallel port. The 'player is running on an IBM compatible personal computer under MS-DOS operation system and stimulus is displayed on a VGA computer monitor. Various stimuli created with this technique for visual evoked potentials (VEPs) are presented.

A Preliminary Empirical Evaluation of Virtual Reality as a Training Tool for Visual-Spatial Tasks

DTIC Science & Technology

1993-05-01

Hillsdale, NJ: Lawrence Erlbaum Associates. Craik , F.I.M., & Lockhart , R.S. (1972). Levels of processing ; A framework for memory research. Journal of...short-term memory (Bower, 1972; Kanigel, 1981), elaborative rehearsai in short-term memory, and subsequent retrieval from long-term memory ( Craik ... Lockhart , 1972; Chase & Ericsson, 1981), ?nd the superiority of gist over verbatim recall of sentences (Bransford & Franks, 1971). Even memory for simple

Linear and Non-Linear Visual Feature Learning in Rat and Humans

PubMed Central

Bossens, Christophe; Op de Beeck, Hans P.

2016-01-01

The visual system processes visual input in a hierarchical manner in order to extract relevant features that can be used in tasks such as invariant object recognition. Although typically investigated in primates, recent work has shown that rats can be trained in a variety of visual object and shape recognition tasks. These studies did not pinpoint the complexity of the features used by these animals. Many tasks might be solved by using a combination of relatively simple features which tend to be correlated. Alternatively, rats might extract complex features or feature combinations which are nonlinear with respect to those simple features. In the present study, we address this question by starting from a small stimulus set for which one stimulus-response mapping involves a simple linear feature to solve the task while another mapping needs a well-defined nonlinear combination of simpler features related to shape symmetry. We verified computationally that the nonlinear task cannot be trivially solved by a simple V1-model. We show how rats are able to solve the linear feature task but are unable to acquire the nonlinear feature. In contrast, humans are able to use the nonlinear feature and are even faster in uncovering this solution as compared to the linear feature. The implications for the computational capabilities of the rat visual system are discussed. PMID:28066201

Development of Experience-based Visible-type Electromagnetic Teaching Materials

NASA Astrophysics Data System (ADS)

Suzuki, Masayoshi; Shima, Kenzou

Electromagnetism is the base of electrical engineering, however, it is one of the most difficult subjects to learn. The small experiments which show the principles of electricity visibly are useful technique to promote these comprehension. For classroom experimental materials to learn basic electromagnetism, we developed rotating magnetic field visualizer, gravity-use generators, simple motors, and electric-field visualizer. We report how we visualized the principles of motors and generators in classroom experiments. In particular, we discuss in detail how to visualize the mechanism of very simple motors. We have been demonstrating the motors in children science classes conducted all over Japan. We developed these experimental materials, and we achieved remarkable results using these materials in the electromagnetism class.

Basic multisensory functions can be acquired after congenital visual pattern deprivation in humans.

PubMed

Putzar, Lisa; Gondan, Matthias; Röder, Brigitte

2012-01-01

People treated for bilateral congenital cataracts offer a model to study the influence of visual deprivation in early infancy on visual and multisensory development. We investigated cross-modal integration capabilities in cataract patients using a simple detection task that provided redundant information to two different senses. In both patients and controls, redundancy gains were consistent with coactivation models, indicating an integrated processing of modality-specific information. This finding is in contrast with recent studies showing impaired higher-level multisensory interactions in cataract patients. The present results suggest that basic cross-modal integrative processes for simple short stimuli do not depend on visual and/or crossmodal input since birth.

Interobject grouping facilitates visual awareness.

PubMed

Stein, Timo; Kaiser, Daniel; Peelen, Marius V

2015-01-01

In organizing perception, the human visual system takes advantage of regularities in the visual input to perceptually group related image elements. Simple stimuli that can be perceptually grouped based on physical regularities, for example by forming an illusory contour, have a competitive advantage in entering visual awareness. Here, we show that regularities that arise from the relative positioning of complex, meaningful objects in the visual environment also modulate visual awareness. Using continuous flash suppression, we found that pairs of objects that were positioned according to real-world spatial regularities (e.g., a lamp above a table) accessed awareness more quickly than the same object pairs shown in irregular configurations (e.g., a table above a lamp). This advantage was specific to upright stimuli and abolished by stimulus inversion, meaning that it did not reflect physical stimulus confounds or the grouping of simple image elements. Thus, knowledge of the spatial configuration of objects in the environment shapes the contents of conscious perception.

A lightning strike to the head causing a visual cortex defect with simple and complex visual hallucinations

PubMed Central

Kleiter, Ingo; Luerding, Ralf; Diendorfer, Gerhard; Rek, Helga; Bogdahn, Ulrich; Schalke, Berthold

2007-01-01

The case of a 23‐year‐old mountaineer who was hit by a lightning strike to the occiput causing a large central visual field defect and bilateral tympanic membrane ruptures is described. Owing to extreme agitation, the patient was set to a drug‐induced coma for 3 days. After extubation, she experienced simple and complex visual hallucinations for several days, but otherwise recovered largely. Neuropsychological tests revealed deficits in fast visual detection tasks and non‐verbal learning, and indicated a right temporal lobe dysfunction, consistent with a right temporal focus on electroencephalography. Four months after the accident, she developed a psychological reaction consisting of nightmares with reappearance of the complex visual hallucinations and a depressive syndrome. Using the European Cooperation for Lightning Detection network, a meteorological system for lightning surveillance, the exact geographical location and nature of the lightning flash were retrospectively retraced. PMID:17369595

A lightning strike to the head causing a visual cortex defect with simple and complex visual hallucinations

PubMed Central

Kleiter, Ingo; Luerding, Ralf; Diendorfer, Gerhard; Rek, Helga; Bogdahn, Ulrich; Schalke, Berthold

2009-01-01

The case of a 23-year-old mountaineer who was hit by a lightning strike to the occiput causing a large central visual field defect and bilateral tympanic membrane ruptures is described. Owing to extreme agitation, the patient was sent into a drug-induced coma for 3 days. After extubation, she experienced simple and complex visual hallucinations for several days, but otherwise largely recovered. Neuropsychological tests revealed deficits in fast visual detection tasks and non-verbal learning and indicated a right temporal lobe dysfunction, consistent with a right temporal focus on electroencephalography. At 4 months after the accident, she developed a psychological reaction consisting of nightmares, with reappearance of the complex visual hallucinations and a depressive syndrome. Using the European Cooperation for Lightning Detection network, a meteorological system for lightning surveillance, the exact geographical location and nature of the lightning strike were retrospectively retraced PMID:21734915

Visual Testing: An Experimental Assessment of the Encoding Specificity Hypothesis.

ERIC Educational Resources Information Center

DeMelo, Hermes T.; And Others

This study of 96 high school biology students investigates the effectiveness of visual instruction composed of simple line drawings and printed words as compared to printed-words-only instruction, visual tests, and the interaction between visual or non-visual mode of instruction and mode of testing. The subjects were randomly assigned to be given…

Synaptic Basis for Differential Orientation Selectivity between Complex and Simple Cells in Mouse Visual Cortex

PubMed Central

Li, Ya-tang; Liu, Bao-hua; Chou, Xiao-lin; Zhang, Li I.

2015-01-01

In the primary visual cortex (V1), orientation-selective neurons can be categorized into simple and complex cells primarily based on their receptive field (RF) structures. In mouse V1, although previous studies have examined the excitatory/inhibitory interplay underlying orientation selectivity (OS) of simple cells, the synaptic bases for that of complex cells have remained obscure. Here, by combining in vivo loose-patch and whole-cell recordings, we found that complex cells, identified by their overlapping on/off subfields, had significantly weaker OS than simple cells at both spiking and subthreshold membrane potential response levels. Voltage-clamp recordings further revealed that although excitatory inputs to complex and simple cells exhibited a similar degree of OS, inhibition in complex cells was more narrowly tuned than excitation, whereas in simple cells inhibition was more broadly tuned than excitation. The differential inhibitory tuning can primarily account for the difference in OS between complex and simple cells. Interestingly, the differential synaptic tuning correlated well with the spatial organization of synaptic input: the inhibitory visual RF in complex cells was more elongated in shape than its excitatory counterpart and also was more elongated than that in simple cells. Together, our results demonstrate that OS of complex and simple cells is differentially shaped by cortical inhibition based on its orientation tuning profile relative to excitation, which is contributed at least partially by the spatial organization of RFs of presynaptic inhibitory neurons. SIGNIFICANCE STATEMENT Simple and complex cells, two classes of principal neurons in the primary visual cortex (V1), are generally thought to be equally selective for orientation. In mouse V1, we report that complex cells, identified by their overlapping on/off subfields, has significantly weaker orientation selectivity (OS) than simple cells. This can be primarily attributed to the differential tuning selectivity of inhibitory synaptic input: inhibition in complex cells is more narrowly tuned than excitation, whereas in simple cells inhibition is more broadly tuned than excitation. In addition, there is a good correlation between inhibitory tuning selectivity and the spatial organization of inhibitory inputs. These complex and simple cells with differential degree of OS may provide functionally distinct signals to different downstream targets. PMID:26245969

Synaptic Basis for Differential Orientation Selectivity between Complex and Simple Cells in Mouse Visual Cortex.

PubMed

Li, Ya-tang; Liu, Bao-hua; Chou, Xiao-lin; Zhang, Li I; Tao, Huizhong W

2015-08-05

In the primary visual cortex (V1), orientation-selective neurons can be categorized into simple and complex cells primarily based on their receptive field (RF) structures. In mouse V1, although previous studies have examined the excitatory/inhibitory interplay underlying orientation selectivity (OS) of simple cells, the synaptic bases for that of complex cells have remained obscure. Here, by combining in vivo loose-patch and whole-cell recordings, we found that complex cells, identified by their overlapping on/off subfields, had significantly weaker OS than simple cells at both spiking and subthreshold membrane potential response levels. Voltage-clamp recordings further revealed that although excitatory inputs to complex and simple cells exhibited a similar degree of OS, inhibition in complex cells was more narrowly tuned than excitation, whereas in simple cells inhibition was more broadly tuned than excitation. The differential inhibitory tuning can primarily account for the difference in OS between complex and simple cells. Interestingly, the differential synaptic tuning correlated well with the spatial organization of synaptic input: the inhibitory visual RF in complex cells was more elongated in shape than its excitatory counterpart and also was more elongated than that in simple cells. Together, our results demonstrate that OS of complex and simple cells is differentially shaped by cortical inhibition based on its orientation tuning profile relative to excitation, which is contributed at least partially by the spatial organization of RFs of presynaptic inhibitory neurons. Simple and complex cells, two classes of principal neurons in the primary visual cortex (V1), are generally thought to be equally selective for orientation. In mouse V1, we report that complex cells, identified by their overlapping on/off subfields, has significantly weaker orientation selectivity (OS) than simple cells. This can be primarily attributed to the differential tuning selectivity of inhibitory synaptic input: inhibition in complex cells is more narrowly tuned than excitation, whereas in simple cells inhibition is more broadly tuned than excitation. In addition, there is a good correlation between inhibitory tuning selectivity and the spatial organization of inhibitory inputs. These complex and simple cells with differential degree of OS may provide functionally distinct signals to different downstream targets. Copyright © 2015 the authors 0270-6474/15/3511081-13$15.00/0.

Distinct responses of Purkinje neurons and roles of simple spikes during associative motor learning in larval zebrafish

PubMed Central

Harmon, Thomas C; Magaram, Uri; McLean, David L; Raman, Indira M

2017-01-01

To study cerebellar activity during learning, we made whole-cell recordings from larval zebrafish Purkinje cells while monitoring fictive swimming during associative conditioning. Fish learned to swim in response to visual stimulation preceding tactile stimulation of the tail. Learning was abolished by cerebellar ablation. All Purkinje cells showed task-related activity. Based on how many complex spikes emerged during learned swimming, they were classified as multiple, single, or zero complex spike (MCS, SCS, ZCS) cells. With learning, MCS and ZCS cells developed increased climbing fiber (MCS) or parallel fiber (ZCS) input during visual stimulation; SCS cells fired complex spikes associated with learned swimming episodes. The categories correlated with location. Optogenetically suppressing simple spikes only during visual stimulation demonstrated that simple spikes are required for acquisition and early stages of expression of learned responses, but not their maintenance, consistent with a transient, instructive role for simple spikes during cerebellar learning in larval zebrafish. DOI: http://dx.doi.org/10.7554/eLife.22537.001 PMID:28541889

Using simple manipulatives to improve student comprehension of a complex biological process: protein synthesis.

PubMed

Guzman, Karen; Bartlett, John

2012-01-01

Biological systems and living processes involve a complex interplay of biochemicals and macromolecular structures that can be challenging for undergraduate students to comprehend and, thus, misconceptions abound. Protein synthesis, or translation, is an example of a biological process for which students often hold many misconceptions. This article describes an exercise that was developed to illustrate the process of translation using simple objects to represent complex molecules. Animations, 3D physical models, computer simulations, laboratory experiments and classroom lectures are also used to reinforce the students' understanding of translation, but by focusing on the simple manipulatives in this exercise, students are better able to visualize concepts that can elude them when using the other methods. The translation exercise is described along with suggestions for background material, questions used to evaluate student comprehension and tips for using the manipulatives to identify common misconceptions. Copyright © 2012 Wiley Periodicals, Inc.

Effects of directional uncertainty on visually-guided joystick pointing.

PubMed

Berryhill, Marian; Kveraga, Kestutis; Hughes, Howard C

2005-02-01

Reaction times generally follow the predictions of Hick's law as stimulus-response uncertainty increases, although notable exceptions include the oculomotor system. Saccadic and smooth pursuit eye movement reaction times are independent of stimulus-response uncertainty. Previous research showed that joystick pointing to targets, a motor analog of saccadic eye movements, is only modestly affected by increased stimulus-response uncertainty; however, a no-uncertainty condition (simple reaction time to 1 possible target) was not included. Here, we re-evaluate manual joystick pointing including a no-uncertainty condition. Analysis indicated simple joystick pointing reaction times were significantly faster than choice reaction times. Choice reaction times (2, 4, or 8 possible target locations) only slightly increased as the number of possible targets increased. These data suggest that, as with joystick tracking (a motor analog of smooth pursuit eye movements), joystick pointing is more closely approximated by a simple/choice step function than the log function predicted by Hick's law.

The Conversion of L-Phenylalanine to ("S")-2-Hydroxy-3-Phenylpropanoic Acid: A Simple, Visual Example of a Stereospecific S[subscript N]2 Reaction

ERIC Educational Resources Information Center

Van Draanen, Nanine A.; Hengst, Stephanie

2010-01-01

We report a simple, inexpensive, visual, and environmentally friendly S[subscript N]2 reaction appropriate for the second-year organic chemistry laboratory that illustrates stereospecificity, dependence of water solubility on the state of ionization, optical activity, and effect of diastereotopic protons in [superscript 1]H NMR spectroscopy. The…

An infrared/video fusion system for military robotics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, A.W.; Roberts, R.S.

1997-08-05

Sensory information is critical to the telerobotic operation of mobile robots. In particular, visual sensors are a key component of the sensor package on a robot engaged in urban military operations. Visual sensors provide the robot operator with a wealth of information including robot navigation and threat assessment. However, simple countermeasures such as darkness, smoke, or blinding by a laser, can easily neutralize visual sensors. In order to provide a robust visual sensing system, an infrared sensor is required to augment the primary visual sensor. An infrared sensor can acquire useful imagery in conditions that incapacitate a visual sensor. Amore » simple approach to incorporating an infrared sensor into the visual sensing system is to display two images to the operator: side-by-side visual and infrared images. However, dual images might overwhelm the operator with information, and result in degraded robot performance. A better solution is to combine the visual and infrared images into a single image that maximizes scene information. Fusing visual and infrared images into a single image demands balancing the mixture of visual and infrared information. Humans are accustom to viewing and interpreting visual images. They are not accustom to viewing or interpreting infrared images. Hence, the infrared image must be used to enhance the visual image, not obfuscate it.« less

Visual flow scene effects on the somatogravic illusion in non-pilots.

PubMed

Eriksson, Lars; von Hofsten, Claes; Tribukait, Arne; Eiken, Ola; Andersson, Peter; Hedström, Johan

2008-09-01

The somatogravic illusion (SGI) is easily broken when the pilot looks out the aircraft window during daylight flight, but it has proven difficult to break or even reduce the SGI in non-pilots in simulators using synthetic visual scenes. Could visual-flow scenes that accommodate compensatory head movement reduce the SGI in naive subjects? We investigated the effects of visual cues on the SGI induced by a human centrifuge. The subject was equipped with a head-tracked, head-mounted display (HMD) and was seated in a fixed gondola facing the center of rotation. The angular velocity of the centrifuge increased from near zero until a 0.57-G centripetal acceleration was attained, resulting in a tilt of the gravitoinertial force vector, corresponding to a pitch-up of 30 degrees. The subject indicated perceived horizontal continuously by means of a manual adjustable-plate system. We performed two experiments with within-subjects designs. In Experiment 1, the subjects (N = 13) viewed a darkened HMD and a presentation of simple visual flow beneath a horizon. In Experiment 2, the subjects (N = 12) viewed a darkened HMD, a scene including symbology superimposed on simple visual flow and horizon, and this scene without visual flow (static). In Experiment 1, visual flow reduced the SGI from 12.4 +/- 1.4 degrees (mean +/- SE) to 8.7 +/- 1.5 degrees. In Experiment 2, the SGI was smaller in the visual flow condition (9.3 +/- 1.8 degrees) than with the static scene (13.3 +/- 1.7 degrees) and without HMD presentation (14.5 +/- 2.3 degrees), respectively. It is possible to reduce the SGI in non-pilots by means of a synthetic horizon and simple visual flow conveyed by a head-tracked HMD. This may reflect the power of a more intuitive display for reducing the SGI.

Evaluation of the safety and usability of touch gestures in operating in-vehicle information systems with visual occlusion.

PubMed

Kim, Huhn; Song, Haewon

2014-05-01

Nowadays, many automobile manufacturers are interested in applying the touch gestures that are used in smart phones to operate their in-vehicle information systems (IVISs). In this study, an experiment was performed to verify the applicability of touch gestures in the operation of IVISs from the viewpoints of both driving safety and usability. In the experiment, two devices were used: one was the Apple iPad, with which various touch gestures such as flicking, panning, and pinching were enabled; the other was the SK EnNavi, which only allowed tapping touch gestures. The participants performed the touch operations using the two devices under visually occluded situations, which is a well-known technique for estimating load of visual attention while driving. In scrolling through a list, the flicking gestures required more time than the tapping gestures. Interestingly, both the flicking and simple tapping gestures required slightly higher visual attention. In moving a map, the average time taken per operation and the visual attention load required for the panning gestures did not differ from those of the simple tapping gestures that are used in existing car navigation systems. In zooming in/out of a map, the average time taken per pinching gesture was similar to that of the tapping gesture but required higher visual attention. Moreover, pinching gestures at a display angle of 75° required that the participants severely bend their wrists. Because the display angles of many car navigation systems tends to be more than 75°, pinching gestures can cause severe fatigue on users' wrists. Furthermore, contrary to participants' evaluation of other gestures, several participants answered that the pinching gesture was not necessary when operating IVISs. It was found that the panning gesture is the only touch gesture that can be used without negative consequences when operating IVISs while driving. The flicking gesture is likely to be used if the screen moving speed is slower or if the car is in heavy traffic. However, the pinching gesture is not an appropriate method of operating IVISs while driving in the various scenarios examined in this study. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Interactive SIGHT: textual access to simple bar charts

NASA Astrophysics Data System (ADS)

Demir, Seniz; Oliver, David; Schwartz, Edward; Elzer, Stephanie; Carberry, Sandra; Mccoy, Kathleen F.; Chester, Daniel

2010-12-01

Information graphics, such as bar charts and line graphs, are an important component of many articles from popular media. The majority of such graphics have an intention (a high-level message) to communicate to the graph viewer. Since the intended message of a graphic is often not repeated in the accompanying text, graphics together with the textual segments contribute to the overall purpose of an article and cannot be ignored. Unfortunately, these visual displays are provided in a format which is not readily accessible to everyone. For example, individuals with sight impairments who use screen readers to listen to documents have limited access to the graphics. This article presents a new accessibility tool, the Interactive SIGHT (Summarizing Information GrapHics Textually) system, that is intended to enable visually impaired users to access the knowledge that one would gain from viewing information graphics found on the web. The current system, which is implemented as a browser extension that works on simple bar charts, can be invoked by a user via a keystroke combination while navigating the web. Once launched, Interactive SIGHT first provides a brief summary that conveys the underlying intention of a bar chart along with the chart's most significant and salient features, and then produces history-aware follow-up responses to provide further information about the chart upon request from the user. We present two user studies that were conducted with sighted and visually impaired users to determine how effective the initial summary and follow-up responses are in conveying the informational content of bar charts, and to evaluate how easy it is to use the system interface. The evaluation results are promising and indicate that the system responses are well-structured and enable visually impaired users to answer key questions about bar charts in an easy-to-use manner. Post-experimental interviews revealed that visually impaired participants were very satisfied with the system offering different options to access the content of a chart to meet their specific needs and that they would use Interactive SIGHT if it was publicly available so as not to have to ignore graphics on the web. Being a language based assistive technology designed to compensate for the lack of sight, our work paves the road for a stronger acceptance of natural language interfaces to graph interpretation that we believe will be of great benefit to the visually impaired community.

Does linear separability really matter? Complex visual search is explained by simple search

PubMed Central

Vighneshvel, T.; Arun, S. P.

2013-01-01

Visual search in real life involves complex displays with a target among multiple types of distracters, but in the laboratory, it is often tested using simple displays with identical distracters. Can complex search be understood in terms of simple searches? This link may not be straightforward if complex search has emergent properties. One such property is linear separability, whereby search is hard when a target cannot be separated from its distracters using a single linear boundary. However, evidence in favor of linear separability is based on testing stimulus configurations in an external parametric space that need not be related to their true perceptual representation. We therefore set out to assess whether linear separability influences complex search at all. Our null hypothesis was that complex search performance depends only on classical factors such as target-distracter similarity and distracter homogeneity, which we measured using simple searches. Across three experiments involving a variety of artificial and natural objects, differences between linearly separable and nonseparable searches were explained using target-distracter similarity and distracter heterogeneity. Further, simple searches accurately predicted complex search regardless of linear separability (r = 0.91). Our results show that complex search is explained by simple search, refuting the widely held belief that linear separability influences visual search. PMID:24029822

Recommendations for the development of e-modules for the continuing professional development of European dentists.

PubMed

Kavadella, A; Kossioni, A E; Tsiklakis, K; Cowpe, J; Bullock, A; Barnes, E; Bailey, S; Thomas, H; Thomas, R; Karaharju-Suvanto, T; Suomalainen, K; Kersten, H; Povel, E; Giles, M; Walmsley, D; Soboleva, U; Liepa, A; Akota, I

2013-05-01

To provide evidence-based and peer-reviewed recommendations for the development of dental continuing professional development (CPD) learning e-modules. The present recommendations are consensus recommendations of the DentCPD project team and were informed by a literature research, consultations from e-learning and IT expert, discussions amongst the participants attending a special interest group during the 2012 ADEE meeting, and feedback from the evaluation procedures of the exemplar e-module (as described in a companion paper within this Supplement). The main focus of these recommendations is on the courses and modules organised and offered by dental schools. E-modules for dental CPD, as well as for other health professionals' continuing education, have been implemented and evaluated for a number of years. Research shows that the development of e-modules is a team process, undertaken by academics, subject experts, pedagogists, IT and web designers, learning technologists and librarians. The e-module must have clear learning objectives (outcomes), addressing the learners' individual needs, and must be visually attractive, relevant, interactive, promoting critical thinking and providing feedback. The text, graphics and animations must support the objectives and enable the learning process by creating an attractive, easy to navigate and interactive electronic environment. Technology is usually a concern for learners and tutors; therefore, it must be kept simple and interoperable within different systems and software. The pedagogical and technological proficiency of educators is of paramount importance, yet remains a challenge in many instances. The development of e-courses and modules for dental CPD is an endeavour undertaken by a group of professionals. It must be underpinned by sound pedagogical and e-learning principles and must incorporate elements for effective visual learning and visual design and a simple, consistent technology. © 2013 John Wiley & Sons A/S.

Visual conspicuity: a new simple standard, its reliability, validity and applicability.

PubMed

Wertheim, A H

2010-03-01

A general standard for quantifying conspicuity is described. It derives from a simple and easy method to quantitatively measure the visual conspicuity of an object. The method stems from the theoretical view that the conspicuity of an object is not a property of that object, but describes the degree to which the object is perceptually embedded in, i.e. laterally masked by, its visual environment. First, three variations of a simple method to measure the strength of such lateral masking are described and empirical evidence for its reliability and its validity is presented, as are several tests of predictions concerning the effects of viewing distance and ambient light. It is then shown how this method yields a conspicuity standard, expressed as a number, which can be made part of a rule of law, and which can be used to test whether or not, and to what extent, the conspicuity of a particular object, e.g. a traffic sign, meets a predetermined criterion. An additional feature is that, when used under different ambient light conditions, the method may also yield an index of the amount of visual clutter in the environment. Taken together the evidence illustrates the methods' applicability in both the laboratory and in real-life situations. STATEMENT OF RELEVANCE: This paper concerns a proposal for a new method to measure visual conspicuity, yielding a numerical index that can be used in a rule of law. It is of importance to ergonomists and human factor specialists who are asked to measure the conspicuity of an object, such as a traffic or rail-road sign, or any other object. The new method is simple and circumvents the need to perform elaborate (search) experiments and thus has great relevance as a simple tool for applied research.

Regional Principal Color Based Saliency Detection

PubMed Central

Lou, Jing; Ren, Mingwu; Wang, Huan

2014-01-01

Saliency detection is widely used in many visual applications like image segmentation, object recognition and classification. In this paper, we will introduce a new method to detect salient objects in natural images. The approach is based on a regional principal color contrast modal, which incorporates low-level and medium-level visual cues. The method allows a simple computation of color features and two categories of spatial relationships to a saliency map, achieving higher F-measure rates. At the same time, we present an interpolation approach to evaluate resulting curves, and analyze parameters selection. Our method enables the effective computation of arbitrary resolution images. Experimental results on a saliency database show that our approach produces high quality saliency maps and performs favorably against ten saliency detection algorithms. PMID:25379960

Comparative evaluation of monocular augmented-reality display for surgical microscopes.

PubMed

Rodriguez Palma, Santiago; Becker, Brian C; Lobes, Louis A; Riviere, Cameron N

2012-01-01

Medical augmented reality has undergone much development recently. However, there is a lack of studies quantitatively comparing the different display options available. This paper compares the effects of different graphical overlay systems in a simple micromanipulation task with "soft" visual servoing. We compared positioning accuracy in a real-time visually-guided task using Micron, an active handheld tremor-canceling microsurgical instrument, using three different displays: 2D screen, 3D screen, and microscope with monocular image injection. Tested with novices and an experienced vitreoretinal surgeon, display of virtual cues in the microscope via an augmented reality injection system significantly decreased 3D error (p < 0.05) compared to the 2D and 3D monitors when confounding factors such as magnification level were normalized.

Simple Smartphone-Based Guiding System for Visually Impaired People

PubMed Central

Lin, Bor-Shing; Lee, Cheng-Che; Chiang, Pei-Ying

2017-01-01

Visually impaired people are often unaware of dangers in front of them, even in familiar environments. Furthermore, in unfamiliar environments, such people require guidance to reduce the risk of colliding with obstacles. This study proposes a simple smartphone-based guiding system for solving the navigation problems for visually impaired people and achieving obstacle avoidance to enable visually impaired people to travel smoothly from a beginning point to a destination with greater awareness of their surroundings. In this study, a computer image recognition system and smartphone application were integrated to form a simple assisted guiding system. Two operating modes, online mode and offline mode, can be chosen depending on network availability. When the system begins to operate, the smartphone captures the scene in front of the user and sends the captured images to the backend server to be processed. The backend server uses the faster region convolutional neural network algorithm or the you only look once algorithm to recognize multiple obstacles in every image, and it subsequently sends the results back to the smartphone. The results of obstacle recognition in this study reached 60%, which is sufficient for assisting visually impaired people in realizing the types and locations of obstacles around them. PMID:28608811

Simple Smartphone-Based Guiding System for Visually Impaired People.

PubMed

Lin, Bor-Shing; Lee, Cheng-Che; Chiang, Pei-Ying

2017-06-13

Visually impaired people are often unaware of dangers in front of them, even in familiar environments. Furthermore, in unfamiliar environments, such people require guidance to reduce the risk of colliding with obstacles. This study proposes a simple smartphone-based guiding system for solving the navigation problems for visually impaired people and achieving obstacle avoidance to enable visually impaired people to travel smoothly from a beginning point to a destination with greater awareness of their surroundings. In this study, a computer image recognition system and smartphone application were integrated to form a simple assisted guiding system. Two operating modes, online mode and offline mode, can be chosen depending on network availability. When the system begins to operate, the smartphone captures the scene in front of the user and sends the captured images to the backend server to be processed. The backend server uses the faster region convolutional neural network algorithm or the you only look once algorithm to recognize multiple obstacles in every image, and it subsequently sends the results back to the smartphone. The results of obstacle recognition in this study reached 60%, which is sufficient for assisting visually impaired people in realizing the types and locations of obstacles around them.

Applying a visual language for image processing as a graphical teaching tool in medical imaging

NASA Astrophysics Data System (ADS)

Birchman, James J.; Tanimoto, Steven L.; Rowberg, Alan H.; Choi, Hyung-Sik; Kim, Yongmin

1992-05-01

Typical user interaction in image processing is with command line entries, pull-down menus, or text menu selections from a list, and as such is not generally graphical in nature. Although applying these interactive methods to construct more sophisticated algorithms from a series of simple image processing steps may be clear to engineers and programmers, it may not be clear to clinicians. A solution to this problem is to implement a visual programming language using visual representations to express image processing algorithms. Visual representations promote a more natural and rapid understanding of image processing algorithms by providing more visual insight into what the algorithms do than the interactive methods mentioned above can provide. Individuals accustomed to dealing with images will be more likely to understand an algorithm that is represented visually. This is especially true of referring physicians, such as surgeons in an intensive care unit. With the increasing acceptance of picture archiving and communications system (PACS) workstations and the trend toward increasing clinical use of image processing, referring physicians will need to learn more sophisticated concepts than simply image access and display. If the procedures that they perform commonly, such as window width and window level adjustment and image enhancement using unsharp masking, are depicted visually in an interactive environment, it will be easier for them to learn and apply these concepts. The software described in this paper is a visual programming language for imaging processing which has been implemented on the NeXT computer using NeXTstep user interface development tools and other tools in an object-oriented environment. The concept is based upon the description of a visual language titled `Visualization of Vision Algorithms' (VIVA). Iconic representations of simple image processing steps are placed into a workbench screen and connected together into a dataflow path by the user. As the user creates and edits a dataflow path, more complex algorithms can be built on the screen. Once the algorithm is built, it can be executed, its results can be reviewed, and operator parameters can be interactively adjusted until an optimized output is produced. The optimized algorithm can then be saved and added to the system as a new operator. This system has been evaluated as a graphical teaching tool for window width and window level adjustment, image enhancement using unsharp masking, and other techniques.

The Components of Smile Design: New York University Smile Evaluation Form Revisited, Update 2015.

PubMed

Calamia, John R; Wolff, Mark S

2015-07-01

This article updates a simple checklist of foundational knowledge in aesthetic dental concepts that allows clinicians to organize their thoughts, to record the concerns of the patient, and to map out those improvements that must be addressed. This adjunct is called a Smile Evaluation Form. Along with other adjuncts such as radiographs, study casts, and diagnostic wax-ups, the Smile Evaluation Form allows clinicians to form a conceptual visualization of the expected end point. It provides a checklist for discussions with other disciplines in the team, to provide a logical sequence of treatment with a mutually agreed-on end point. Copyright © 2015 Elsevier Inc. All rights reserved.

Developing visual images for communicating information aboutantiretroviral side effects to a low-literate population.

PubMed

Dowse, Ros; Ramela, Thato; Barford, Kirsty-Lee; Browne, Sara

2010-09-01

The side effects of antiretroviral (ARV) therapy are linked to altered quality of life and adherence. Poor adherence has also been associated with low health-literacy skills, with an uninformed patient more likely to make ARV-related decisions that compromise the efficacy of the treatment. Low literacy skills disempower patients in interactions with healthcare providers and preclude the use of existing written patient information materials, which are generally written at a high reading level. Visual images or pictograms used as a counselling tool or included in patient information leaflets have been shown to improve patients' knowledge, particularly in low-literate groups. The objective of this study was to design visuals or pictograms illustrating various ARV side effects and to evaluate them in a low-literate South African Xhosa population. Core images were generated either from a design workshop or from posed photos or images from textbooks. The research team worked closely with a graphic artist. Initial versions of the images were discussed and assessed in group discussions, and then modified and eventually evaluated quantitatively in individual interviews with 40 participants who each had a maximum of 10 years of schooling. The familiarity of the human body, its facial expressions, postures and actions contextualised the information and contributed to the participants' understanding. Visuals that were simple, had a clear central focus and reflected familiar body experiences (e.g. vomiting) were highly successful. The introduction of abstract elements (e.g. fever) and metaphorical images (e.g. nightmares) presented problems for interpretation, particularly to those with the lowest educational levels. We recommend that such visual images should be designed in collaboration with the target population and a graphic artist, taking cognisance of the audience's literacy skills and culture, and should employ a multistage iterative process of modification and evaluation.

[A cross-sectional study on the visual disability of the residents in 2006 in Henan province, China].

PubMed

Li, Yin-yin; Zhu, Yu; Li, Zhi-gang; Chen, Ping; Yan, Shao-jun

2009-09-01

To explore the status on visual disability and the leading causes in residents in Henan Province. It was a cross-sectional study and a part of the National Epidemiological Study on the disability in 2006. Sample size 120 000 was assigned to Henan study by the protocol of the National epidemiological study on the disability. Stratified, equal interval, proportional probability; four-stage sampling was adopted. Survey teams were organized, and survey personnel was trained in the sampled counties and cities. Visual disabled persons were screened by home to home visit and confirmed by ophthalmologists. 130 415 persons in 36 923 households were studied. 1973 persons were confirmed to have the visual disability, the prevalence was 1.51%. Among them, 1376 persons just suffer from the visual disability (simple visual disability), 579 persons had multiple disability including the visual disability (multiple disability). Among them, 643 persons (0.49%) were blindness, 1330 persons (1.02%) were low vision. The age of the most of the persons with visual disability was more than 50 years old. The prevalence of the simple visual disability in male and female was 0.77% and 1.36% respectively and had significant statistical difference (chi(2) = 105.687, P < 0.01). The prevalence of the simple visual disability in urban and rural area was 0.58% and 1.15% respectively and also had significant statistical difference (chi(2) = 56.047, P < 0.01). The first five leading causes of the visual disability were cataract (54.69%), retinal and choroidal diseases (8.21%), corneal diseases (5.83%), genetic and congenital eye diseases (5.07%) and glaucoma (4.56%). Government and health organizations should pay more attention to the prevention and treatment the visual disability in Henan province, especially the prevention and treatment of cataract, retinal and choroidal diseases, corneal diseases, genetic and congenital eye diseases and glaucoma.

PubMed Central

Hackethal, Andreas; Hirschburger, Markus; Eicker, Sven Oliver; Mücke, Thomas; Lindner, Christoph; Buchweitz, Olaf

2018-01-01

Modern surgical strategies aim to reduce trauma by using functional imaging to improve surgical outcomes. This reviews considers and evaluates the importance of the fluorescent dye indocyanine green (ICG) to visualize lymph nodes, lymphatic pathways and vessels and tissue borders in an interdisciplinary setting. The work is based on a selective search of the literature in PubMed, Scopus, and Google Scholar and the authorsʼ own clinical experience. Because of its simple, radiation-free and uncomplicated application, ICG has become an important clinical indicator in recent years. In oncologic surgery ICG is used extensively to identify sentinel lymph nodes with promising results. In some studies, the detection rates with ICG have been better than the rates obtained with established procedures. When ICG is used for visualization and the quantification of tissue perfusion, it can lead to fewer cases of anastomotic insufficiency or transplant necrosis. The use of ICG for the imaging of organ borders, flap plasty borders and postoperative vascularization has also been scientifically evaluated. Combining the easily applied ICG dye with technical options for intraoperative and interventional visualization has the potential to create new functional imaging procedures which, in future, could expand or even replace existing established surgical techniques, particularly the techniques used for sentinel lymph node and anastomosis imaging. PMID:29375146

An Ideal Observer Analysis of Visual Working Memory

PubMed Central

Sims, Chris R.; Jacobs, Robert A.; Knill, David C.

2013-01-01

Limits in visual working memory (VWM) strongly constrain human performance across many tasks. However, the nature of these limits is not well understood. In this paper we develop an ideal observer analysis of human visual working memory, by deriving the expected behavior of an optimally performing, but limited-capacity memory system. This analysis is framed around rate–distortion theory, a branch of information theory that provides optimal bounds on the accuracy of information transmission subject to a fixed information capacity. The result of the ideal observer analysis is a theoretical framework that provides a task-independent and quantitative definition of visual memory capacity and yields novel predictions regarding human performance. These predictions are subsequently evaluated and confirmed in two empirical studies. Further, the framework is general enough to allow the specification and testing of alternative models of visual memory (for example, how capacity is distributed across multiple items). We demonstrate that a simple model developed on the basis of the ideal observer analysis—one which allows variability in the number of stored memory representations, but does not assume the presence of a fixed item limit—provides an excellent account of the empirical data, and further offers a principled re-interpretation of existing models of visual working memory. PMID:22946744

On the use of Augmented Reality techniques in learning and interpretation of cardiologic data.

PubMed

Lamounier, Edgard; Bucioli, Arthur; Cardoso, Alexandre; Andrade, Adriano; Soares, Alcimar

2010-01-01

Augmented Reality is a technology which provides people with more intuitive ways of interaction and visualization, close to those in real world. The amount of applications using Augmented Reality is growing every day, and results can be already seen in several fields such as Education, Training, Entertainment and Medicine. The system proposed in this article intends to provide a friendly and intuitive interface based on Augmented Reality for heart beating evaluation and visualization. Cardiologic data is loaded from several distinct sources: simple standards of heart beating frequencies (for example situations like running or sleeping), files of heart beating signals, scanned electrocardiographs and real time data acquisition of patient's heart beating. All this data is processed to produce visualization within Augmented Reality environments. The results obtained in this research have shown that the developed system is able to simplify the understanding of concepts about heart beating and its functioning. Furthermore, the system can help health professionals in the task of retrieving, processing and converting data from all the sources handled by the system, with the support of an edition and visualization mode.

Estimated capacity of object files in visual short-term memory is not improved by retrieval cueing.

PubMed

Saiki, Jun; Miyatsuji, Hirofumi

2009-03-23

Visual short-term memory (VSTM) has been claimed to maintain three to five feature-bound object representations. Some results showing smaller capacity estimates for feature binding memory have been interpreted as the effects of interference in memory retrieval. However, change-detection tasks may not properly evaluate complex feature-bound representations such as triple conjunctions in VSTM. To understand the general type of feature-bound object representation, evaluation of triple conjunctions is critical. To test whether interference occurs in memory retrieval for complete object file representations in a VSTM task, we cued retrieval in novel paradigms that directly evaluate the memory for triple conjunctions, in comparison with a simple change-detection task. In our multiple object permanence tracking displays, observers monitored for a switch in feature combination between objects during an occlusion period, and we found that a retrieval cue provided no benefit with the triple conjunction tasks, but significant facilitation with the change-detection task, suggesting that low capacity estimates of object file memory in VSTM reflect a limit on maintenance, not retrieval.

[Change settings for visual analyzer of child users of mobile communication: longitudinal study].

PubMed

Khorseva, N I; Grigor'ev, Iu G; Gorbunova, N V

2014-01-01

The paper represents theresults of longitudinal monitoring of the changes in the parameters of simple visual-motor reaction, the visual acuity and the rate of the visual discrimination in the child users of mobile communication, which indicate the multivariability of the possible effects of radiation from mobile phones on the auditory system of children.

Building simple multiscale visualizations of outcrop geology using virtual reality modeling language (VRML)

NASA Astrophysics Data System (ADS)

Thurmond, John B.; Drzewiecki, Peter A.; Xu, Xueming

2005-08-01

Geological data collected from outcrop are inherently three-dimensional (3D) and span a variety of scales, from the megascopic to the microscopic. This presents challenges in both interpreting and communicating observations. The Virtual Reality Modeling Language provides an easy way for geoscientists to construct complex visualizations that can be viewed with free software. Field data in tabular form can be used to generate hierarchical multi-scale visualizations of outcrops, which can convey the complex relationships between a variety of data types simultaneously. An example from carbonate mud-mounds in southeastern New Mexico illustrates the embedding of three orders of magnitude of observation into a single visualization, for the purpose of interpreting depositional facies relationships in three dimensions. This type of raw data visualization can be built without software tools, yet is incredibly useful for interpreting and communicating data. Even simple visualizations can aid in the interpretation of complex 3D relationships that are frequently encountered in the geosciences.

Mechanisms of Neuronal Computation in Mammalian Visual Cortex

PubMed Central

Priebe, Nicholas J.; Ferster, David

2012-01-01

Orientation selectivity in the primary visual cortex (V1) is a receptive field property that is at once simple enough to make it amenable to experimental and theoretical approaches and yet complex enough to represent a significant transformation in the representation of the visual image. As a result, V1 has become an area of choice for studying cortical computation and its underlying mechanisms. Here we consider the receptive field properties of the simple cells in cat V1—the cells that receive direct input from thalamic relay cells—and explore how these properties, many of which are highly nonlinear, arise. We have found that many receptive field properties of V1 simple cells fall directly out of Hubel and Wiesel’s feedforward model when the model incorporates realistic neuronal and synaptic mechanisms, including threshold, synaptic depression, response variability, and the membrane time constant. PMID:22841306

Single Canonical Model of Reflexive Memory and Spatial Attention

PubMed Central

Patel, Saumil S.; Red, Stuart; Lin, Eric; Sereno, Anne B.

2015-01-01

Many neurons in the dorsal and ventral visual stream have the property that after a brief visual stimulus presentation in their receptive field, the spiking activity in these neurons persists above their baseline levels for several seconds. This maintained activity is not always correlated with the monkey’s task and its origin is unknown. We have previously proposed a simple neural network model, based on shape selective neurons in monkey lateral intraparietal cortex, which predicts the valence and time course of reflexive (bottom-up) spatial attention. In the same simple model, we demonstrate here that passive maintained activity or short-term memory of specific visual events can result without need for an external or top-down modulatory signal. Mutual inhibition and neuronal adaptation play distinct roles in reflexive attention and memory. This modest 4-cell model provides the first simple and unified physiologically plausible mechanism of reflexive spatial attention and passive short-term memory processes. PMID:26493949

[Digital processing and evaluation of ultrasound images].

PubMed

Borchers, J; Klews, P M

1993-10-01

With the help of workstations and PCs, on-site image processing has become possible. If the images are not available in digital form the video signal has to be A/D converted. In the case of colour images the colour channels R (red), G (green) and B (blue) have to be digitized separately. "Truecolour" imaging calls for an 8 bit resolution per channel, leading to 24 bits per pixel. Out of a pool of 2(24) possible values only the relevant 128 gray values and 64 shades of red and blue respectively needed for a colour-coded ultrasound image have to be isolated. Digital images can be changed and evaluated with the help of readily available image evaluation programmes. It is mandatory that during image manipulation the gray scale and colour pixels and LUTs (Look-Up-Table) must be worked on separately. Using relatively simple LUT manipulations astonishing image improvements are possible. Application of simple mathematical operations can lead to completely new clinical results. For example, by subtracting two consecutive colour flow images in time and special LUT operations, local acceleration of blood flow can be visualized (Colour Acceleration Imaging).

The effect of changing the secondary task in dual-task paradigms for measuring listening effort.

PubMed

Picou, Erin M; Ricketts, Todd A

2014-01-01

The purpose of this study was to evaluate the effect of changing the secondary task in dual-task paradigms that measure listening effort. Specifically, the effects of increasing the secondary task complexity or the depth of processing on a paradigm's sensitivity to changes in listening effort were quantified in a series of two experiments. Specific factors investigated within each experiment were background noise and visual cues. Participants in Experiment 1 were adults with normal hearing (mean age 23 years) and participants in Experiment 2 were adults with mild sloping to moderately severe sensorineural hearing loss (mean age 60.1 years). In both experiments, participants were tested using three dual-task paradigms. These paradigms had identical primary tasks, which were always monosyllable word recognition. The secondary tasks were all physical reaction time measures. The stimulus for the secondary task varied by paradigm and was a (1) simple visual probe, (2) a complex visual probe, or (3) the category of word presented. In this way, the secondary tasks mainly varied from the simple paradigm by either complexity or depth of speech processing. Using all three paradigms, participants were tested in four conditions, (1) auditory-only stimuli in quiet, (2) auditory-only stimuli in noise, (3) auditory-visual stimuli in quiet, and (4) auditory-visual stimuli in noise. During auditory-visual conditions, the talker's face was visible. Signal-to-noise ratios used during conditions with background noise were set individually so word recognition performance was matched in auditory-only and auditory-visual conditions. In noise, word recognition performance was approximately 80% and 65% for Experiments 1 and 2, respectively. For both experiments, word recognition performance was stable across the three paradigms, confirming that none of the secondary tasks interfered with the primary task. In Experiment 1 (listeners with normal hearing), analysis of median reaction times revealed a significant main effect of background noise on listening effort only with the paradigm that required deep processing. Visual cues did not change listening effort as measured with any of the three dual-task paradigms. In Experiment 2 (listeners with hearing loss), analysis of median reaction times revealed expected significant effects of background noise using all three paradigms, but no significant effects of visual cues. None of the dual-task paradigms were sensitive to the effects of visual cues. Furthermore, changing the complexity of the secondary task did not change dual-task paradigm sensitivity to the effects of background noise on listening effort for either group of listeners. However, the paradigm whose secondary task involved deeper processing was more sensitive to the effects of background noise for both groups of listeners. While this paradigm differed from the others in several respects, depth of processing may be partially responsible for the increased sensitivity. Therefore, this paradigm may be a valuable tool for evaluating other factors that affect listening effort.

Development of a Paradigm to Assess Nutritive and Biochemical Substances in Humans: A Preliminary Report on the Effects of Tyrosine upon Altitude- and Cold-Induced Stress Responses

DTIC Science & Technology

1987-03-01

3/4 hours. Performance tests evaluated simple and choice reaction time to visual stimuli, vigilance, and processing of symbolic, numerical, verbal...minimize the adverse consequences of these stressors. Tyrosine enhanced performance (e.g. complex information processing , vigilance, and reaction time... processes inherent in many real-world tasks. For example, Map Compass requires association of Wsi PL AFCm uA O-SV CHETCLtISS) direction and degree

A computer program for the localization of small areas in roentgenological images

NASA Technical Reports Server (NTRS)

Keller, R. A.; Baily, N. A.

1976-01-01

A method and associated algorithm are presented which allow a simple and accurate determination to be made of the location of small symmetric areas presented in roentgenological images. The method utilizes an operator to visually spot object positions but eliminates the need for critical positioning accuracy on the operator's part. The rapidity of measurement allows results to be evaluated on-line. Parameters associated with the algorithm have been analyzed, and methods to facilitate an optimum choice for any particular experimental setup are presented.

Computational Model of Primary Visual Cortex Combining Visual Attention for Action Recognition

PubMed Central

Shu, Na; Gao, Zhiyong; Chen, Xiangan; Liu, Haihua

2015-01-01

Humans can easily understand other people’s actions through visual systems, while computers cannot. Therefore, a new bio-inspired computational model is proposed in this paper aiming for automatic action recognition. The model focuses on dynamic properties of neurons and neural networks in the primary visual cortex (V1), and simulates the procedure of information processing in V1, which consists of visual perception, visual attention and representation of human action. In our model, a family of the three-dimensional spatial-temporal correlative Gabor filters is used to model the dynamic properties of the classical receptive field of V1 simple cell tuned to different speeds and orientations in time for detection of spatiotemporal information from video sequences. Based on the inhibitory effect of stimuli outside the classical receptive field caused by lateral connections of spiking neuron networks in V1, we propose surround suppressive operator to further process spatiotemporal information. Visual attention model based on perceptual grouping is integrated into our model to filter and group different regions. Moreover, in order to represent the human action, we consider the characteristic of the neural code: mean motion map based on analysis of spike trains generated by spiking neurons. The experimental evaluation on some publicly available action datasets and comparison with the state-of-the-art approaches demonstrate the superior performance of the proposed model. PMID:26132270

Specvis: Free and open-source software for visual field examination.

PubMed

Dzwiniel, Piotr; Gola, Mateusz; Wójcik-Gryciuk, Anna; Waleszczyk, Wioletta J

2017-01-01

Visual field impairment affects more than 100 million people globally. However, due to the lack of the access to appropriate ophthalmic healthcare in undeveloped regions as a result of associated costs and expertise this number may be an underestimate. Improved access to affordable diagnostic software designed for visual field examination could slow the progression of diseases, such as glaucoma, allowing for early diagnosis and intervention. We have developed Specvis, a free and open-source application written in Java programming language that can run on any personal computer to meet this requirement (http://www.specvis.pl/). Specvis was tested on glaucomatous, retinitis pigmentosa and stroke patients and the results were compared to results using the Medmont M700 Automated Static Perimeter. The application was also tested for inter-test intrapersonal variability. The results from both validation studies indicated low inter-test intrapersonal variability, and suitable reliability for a fast and simple assessment of visual field impairment. Specvis easily identifies visual field areas of zero sensitivity and allows for evaluation of its levels throughout the visual field. Thus, Specvis is a new, reliable application that can be successfully used for visual field examination and can fill the gap between confrontation and perimetry tests. The main advantages of Specvis over existing methods are its availability (free), affordability (runs on any personal computer), and reliability (comparable to high-cost solutions).

Specvis: Free and open-source software for visual field examination

PubMed Central

Dzwiniel, Piotr; Gola, Mateusz; Wójcik-Gryciuk, Anna

2017-01-01

Visual field impairment affects more than 100 million people globally. However, due to the lack of the access to appropriate ophthalmic healthcare in undeveloped regions as a result of associated costs and expertise this number may be an underestimate. Improved access to affordable diagnostic software designed for visual field examination could slow the progression of diseases, such as glaucoma, allowing for early diagnosis and intervention. We have developed Specvis, a free and open-source application written in Java programming language that can run on any personal computer to meet this requirement (http://www.specvis.pl/). Specvis was tested on glaucomatous, retinitis pigmentosa and stroke patients and the results were compared to results using the Medmont M700 Automated Static Perimeter. The application was also tested for inter-test intrapersonal variability. The results from both validation studies indicated low inter-test intrapersonal variability, and suitable reliability for a fast and simple assessment of visual field impairment. Specvis easily identifies visual field areas of zero sensitivity and allows for evaluation of its levels throughout the visual field. Thus, Specvis is a new, reliable application that can be successfully used for visual field examination and can fill the gap between confrontation and perimetry tests. The main advantages of Specvis over existing methods are its availability (free), affordability (runs on any personal computer), and reliability (comparable to high-cost solutions). PMID:29028825

Cranial Nerve II

PubMed Central

Gillig, Paulette Marie; Sanders, Richard D.

2009-01-01

This article contains a brief review of the anatomy of the visual system, a survey of diseases of the retina, optic nerve and lesions of the optic chiasm, and other visual field defects of special interest to the psychiatrist. It also includes a presentation of the corticothalamic mechanisms, differential diagnosis, and various manifestations of visual illusions, and simple and complex visual hallucinations, as well as the differential diagnoses of these various visual phenomena. PMID:19855858

Idiosyncratic characteristics of saccadic eye movements when viewing different visual environments.

PubMed

Andrews, T J; Coppola, D M

1999-08-01

Eye position was recorded in different viewing conditions to assess whether the temporal and spatial characteristics of saccadic eye movements in different individuals are idiosyncratic. Our aim was to determine the degree to which oculomotor control is based on endogenous factors. A total of 15 naive subjects viewed five visual environments: (1) The absence of visual stimulation (i.e. a dark room); (2) a repetitive visual environment (i.e. simple textured patterns); (3) a complex natural scene; (4) a visual search task; and (5) reading text. Although differences in visual environment had significant effects on eye movements, idiosyncrasies were also apparent. For example, the mean fixation duration and size of an individual's saccadic eye movements when passively viewing a complex natural scene covaried significantly with those same parameters in the absence of visual stimulation and in a repetitive visual environment. In contrast, an individual's spatio-temporal characteristics of eye movements during active tasks such as reading text or visual search covaried together, but did not correlate with the pattern of eye movements detected when viewing a natural scene, simple patterns or in the dark. These idiosyncratic patterns of eye movements in normal viewing reveal an endogenous influence on oculomotor control. The independent covariance of eye movements during different visual tasks shows that saccadic eye movements during active tasks like reading or visual search differ from those engaged during the passive inspection of visual scenes.

Simple real-time computerized tasks for detection of malingering among murderers with schizophrenia.

PubMed

Kertzman, Semion; Grinspan, Haim; Birger, Moshe; Shliapnikov, Nina; Alish, Yakov; Ben Nahum, Zeev; Mester, Roberto; Kotler, Moshe

2006-01-01

It is our contention that computer-based two-alternative forced choice techniques can be useful tools for the detection of patients with schizophrenia who feign acute psychotic symptoms and cognitive impairment as opposed to patients with schizophrenia with a true active psychosis. In our experiment, Visual Simple and Choice Reaction Time tasks were used. Reaction time in milliseconds was recorded and accuracy rate was obtained for all subjects' responses. Both types of task were administered to 27 patients with schizophrenia suspected of having committed murder. Patients with schizophrenia who were clinically assessed as malingerers achieved significantly fewer correct results, were significantly slower and less consistent in their reaction time. Congruence of performance between the Simple and Choice tasks was an additional parameter for the accurate diagnosis of malingering. The four parameters of both tests (accuracy of response, reaction time, standard deviation of reaction time and task congruency) are simple and constitute a user-friendly means for the detection of malingering in forensic practice. Another advantage of this procedure is that the software automatically measures and evaluates all the parameters.

Use of standardized visual assessments of riparian and stream condition to manage riparian bird habitat in eastern Oregon.

PubMed

Cooke, Hilary A; Zack, Steve

2009-07-01

The importance of riparian vegetation to support stream function and provide riparian bird habitat in semiarid landscapes suggests that standardized assessment tools that include vegetation criteria to evaluate stream health could also be used to assess habitat conditions for riparian-dependent birds. We first evaluated the ability of two visual assessments of woody vegetation in the riparian zone (corridor width and height) to describe variation in the obligate riparian bird ensemble along 19 streams in eastern Oregon. Overall species richness and the abundances of three species all correlated significantly with both, but width was more important than height. We then examined the utility of the riparian zone criteria in three standardized and commonly used rapid visual riparian assessment protocols--the USDI BLM Proper Functioning Condition (PFC) assessment, the USDA NRCS Stream Visual Assessment Protocol (SVAP), and the U.S. EPA Habitat Assessment Field Data Sheet (HAFDS)--to assess potential riparian bird habitat. Based on the degree of correlation of bird species richness with assessment ratings, we found that PFC does not assess obligate riparian bird habitat condition, SVAP provides a coarse estimate, and HAFDS provides the best assessment. We recommend quantitative measures of woody vegetation for all assessments and that all protocols incorporate woody vegetation height. Given that rapid assessments may be the only source of information for thousands of kilometers of streams in the western United States, incorporating simple vegetation measurements is a critical step in evaluating the status of riparian bird habitat and provides a tool for tracking changes in vegetation condition resulting from management decisions.

Development of orientation tuning in simple cells of primary visual cortex

PubMed Central

Moore, Bartlett D.

2012-01-01

Orientation selectivity and its development are basic features of visual cortex. The original model of orientation selectivity proposes that elongated simple cell receptive fields are constructed from convergent input of an array of lateral geniculate nucleus neurons. However, orientation selectivity of simple cells in the visual cortex is generally greater than the linear contributions based on projections from spatial receptive field profiles. This implies that additional selectivity may arise from intracortical mechanisms. The hierarchical processing idea implies mainly linear connections, whereas cortical contributions are generally considered to be nonlinear. We have explored development of orientation selectivity in visual cortex with a focus on linear and nonlinear factors in a population of anesthetized 4-wk postnatal kittens and adult cats. Linear contributions are estimated from receptive field maps by which orientation tuning curves are generated and bandwidth is quantified. Nonlinear components are estimated as the magnitude of the power function relationship between responses measured from drifting sinusoidal gratings and those predicted from the spatial receptive field. Measured bandwidths for kittens are slightly larger than those in adults, whereas predicted bandwidths are substantially broader. These results suggest that relatively strong nonlinearities in early postnatal stages are substantially involved in the development of orientation tuning in visual cortex. PMID:22323631

Estimating Starch Content in Roots of Deciduous Trees--A Visual Technique

Treesearch

Philip M. Wargo; Philip M. Wargo

1975-01-01

A visual technique for determining starch content in roots of forest trees, based onz iodine-staining of starch granules, was compared with a chemical method. Although the chemical method was more precise, roots could be sorted with the visual method into groups that are probably biologically important. The visual technique is simple and can be adapted for use in the...

Ophthalmologic abnormalities among students with cognitive impairment in eastern Taiwan: The special group with undetected visual impairment.

PubMed

Tsao, Wei-Shan; Hsieh, Hsi-Pao; Chuang, Yi-Ting; Sheu, Min-Muh

2017-05-01

Students with cognitive impairment are at increased risk of suffering from visual impairment due to refractive errors and ocular disease, which can adversely influence learning and daily activities. The purpose of this study was to evaluate the ocular and visual status among students at the special education school in Hualien. All students at the National Hualien Special Education School were evaluated. Full eye examinations were conducted by a skilled ophthalmologist. The students' medical records and disability types were reviewed. A total of 241 students, aged 7-18 years, were examined. Visual acuity could be assessed in 138 students. A total of 169/477 (35.4%) eyes were found to suffer from refractive errors, including 20 eyes with high myopia (≤-6.0 D) and 16 eyes with moderate hypermetropia (+3.0 D to +5.0 D). A total of 84/241 (34.8%) students needed spectacles to correct their vision, thus improving their daily activities and learning process, but only 15/241 (6.2%) students were wearing suitable corrective spectacles. A total of 55/241 students (22.8%) had ocular disorders, which influenced their visual function. The multiple disability group had a statistically significant higher prevalence of ocular disorders (32.9%) than the simple intellectual disability group (19.6%). Students with cognitive impairment in eastern Taiwan have a high risk of visual impairment due to refractive errors and ocular disorders. Importantly, many students have unrecognized correctable refractive errors. Regular ophthalmic examination should be administered to address this issue and prevent further disability in this already handicapped group. Copyright © 2016. Published by Elsevier B.V.

Students' Visual Learning Disabilities and Under-Achievement in Selected Science Subjects.

ERIC Educational Resources Information Center

Rochford, Kevin

Two experiments were conducted to assess the performance of freshmen chemistry students with poor spatial visualization skills. In the first experiment, 31 chemistry students with academically deficient backgrounds completed a diagnostic test of their ability to visualize and interpret pictorial representations of simple molecular structures. At…

Visual Processing Deficits in Children with Slow RAN Performance

ERIC Educational Resources Information Center

Stainthorp, Rhona; Stuart, Morag; Powell, Daisy; Quinlan, Philip; Garwood, Holly

2010-01-01

Two groups of 8- to 10-year-olds differing in rapid automatized naming speed but matched for age, verbal and nonverbal ability, phonological awareness, phonological memory, and visual acuity participated in four experiments investigating early visual processing. As low RAN children had significantly slower simple reaction times (SRT) this was…

Modeling Spatial and Temporal Aspects of Visual Backward Masking

ERIC Educational Resources Information Center

Hermens, Frouke; Luksys, Gediminas; Gerstner, Wulfram; Herzog, Michael H.; Ernst, Udo

2008-01-01

Visual backward masking is a versatile tool for understanding principles and limitations of visual information processing in the human brain. However, the mechanisms underlying masking are still poorly understood. In the current contribution, the authors show that a structurally simple mathematical model can explain many spatial and temporal…

Success in Architecture: Handedness and/or Visual Thinking.

ERIC Educational Resources Information Center

Peterson, John M.; Lansky, Leonard M.

1980-01-01

Some data on sex and handedness in relation to academic predictors and success in architectural education were reexamined. The new variable was the notion of visual thinking, measured by the manner, "visually" or "cognitively," of executing a simple line drawing. As expected, significant differences appeared between persons using these modes.…

Development of a Low-Cost, Noninvasive, Portable Visual Speech Recognition Program.

PubMed

Kohlberg, Gavriel D; Gal, Ya'akov Kobi; Lalwani, Anil K

2016-09-01

Loss of speech following tracheostomy and laryngectomy severely limits communication to simple gestures and facial expressions that are largely ineffective. To facilitate communication in these patients, we seek to develop a low-cost, noninvasive, portable, and simple visual speech recognition program (VSRP) to convert articulatory facial movements into speech. A Microsoft Kinect-based VSRP was developed to capture spatial coordinates of lip movements and translate them into speech. The articulatory speech movements associated with 12 sentences were used to train an artificial neural network classifier. The accuracy of the classifier was then evaluated on a separate, previously unseen set of articulatory speech movements. The VSRP was successfully implemented and tested in 5 subjects. It achieved an accuracy rate of 77.2% (65.0%-87.6% for the 5 speakers) on a 12-sentence data set. The mean time to classify an individual sentence was 2.03 milliseconds (1.91-2.16). We have demonstrated the feasibility of a low-cost, noninvasive, portable VSRP based on Kinect to accurately predict speech from articulation movements in clinically trivial time. This VSRP could be used as a novel communication device for aphonic patients. © The Author(s) 2016.

Damage Evaluation Based on a Wave Energy Flow Map Using Multiple PZT Sensors

PubMed Central

Liu, Yaolu; Hu, Ning; Xu, Hong; Yuan, Weifeng; Yan, Cheng; Li, Yuan; Goda, Riu; Alamusi; Qiu, Jinhao; Ning, Huiming; Wu, Liangke

2014-01-01

A new wave energy flow (WEF) map concept was proposed in this work. Based on it, an improved technique incorporating the laser scanning method and Betti's reciprocal theorem was developed to evaluate the shape and size of damage as well as to realize visualization of wave propagation. In this technique, a simple signal processing algorithm was proposed to construct the WEF map when waves propagate through an inspection region, and multiple lead zirconate titanate (PZT) sensors were employed to improve inspection reliability. Various damages in aluminum and carbon fiber reinforced plastic laminated plates were experimentally and numerically evaluated to validate this technique. The results show that it can effectively evaluate the shape and size of damage from wave field variations around the damage in the WEF map. PMID:24463430

Hawkeye and AMOS: visualizing and assessing the quality of genome assemblies

PubMed Central

Schatz, Michael C.; Phillippy, Adam M.; Sommer, Daniel D.; Delcher, Arthur L.; Puiu, Daniela; Narzisi, Giuseppe; Salzberg, Steven L.; Pop, Mihai

2013-01-01

Since its launch in 2004, the open-source AMOS project has released several innovative DNA sequence analysis applications including: Hawkeye, a visual analytics tool for inspecting the structure of genome assemblies; the Assembly Forensics and FRCurve pipelines for systematically evaluating the quality of a genome assembly; and AMOScmp, the first comparative genome assembler. These applications have been used to assemble and analyze dozens of genomes ranging in complexity from simple microbial species through mammalian genomes. Recent efforts have been focused on enhancing support for new data characteristics brought on by second- and now third-generation sequencing. This review describes the major components of AMOS in light of these challenges, with an emphasis on methods for assessing assembly quality and the visual analytics capabilities of Hawkeye. These interactive graphical aspects are essential for navigating and understanding the complexities of a genome assembly, from the overall genome structure down to individual bases. Hawkeye and AMOS are available open source at http://amos.sourceforge.net. PMID:22199379

Two Methods for Teaching Simple Visual Discriminations to Learners with Severe Disabilities

ERIC Educational Resources Information Center

Graff, Richard B.; Green, Gina

2004-01-01

Simple discriminations are involved in many functional skills; additionally, they are components of conditional discriminations (identity and arbitrary matching-to-sample), which are involved in a wide array of other important performances. Many individuals with severe disabilities have difficulty acquiring simple discriminations with standard…

Rapid screening test for gestational diabetes: public health need, market requirement, initial product design, and experimental results

NASA Astrophysics Data System (ADS)

Weigl, Bernhard H.; Zwisler, Greg; Peck, Roger; Abu-Haydar, Elizabeth

2013-03-01

Gestational diabetes is a global epidemic where many urban areas in Southeast Asia have found prevalence rates as high as 20%, exceeding the highest prevalence rates in the developed world. It can have serious and life-threatening consequences for mothers and babies. We are developing two variants of a new, simple, low-cost rapid test for screening for gestational diabetes mellitus for use primarily in low-resource settings. The pair of assays, both semiquantitative rapid diagnostic strip tests for glycated albumin, require neither fasting nor an oral glucose challenge test. One variant is an extremely simple strip test to estimate the level of total glycated albumin in blood. The other, which is slightly more complex and expensive, is a test that determines the ratio of glycated albumin to total albumin. The screening results can be used to refer women to receive additional care during delivery to avoid birth complications as well as counseling on diet and exercise during and after pregnancy. Results with the latter test may also be used to start treatment with glucose-lowering drugs. Both assays will be read visually. We present initial results of a preliminary cost-performance comparison model evaluating the proposed test versus existing alternatives. We also evaluated user needs and schematic paper microfluidics-based designs aimed at overcoming the challenge of visualizing relatively narrow differences between normal and elevated levels of glycated albumin in blood.

The Attentional Drift Diffusion Model of Simple Perceptual Decision-Making.

PubMed

Tavares, Gabriela; Perona, Pietro; Rangel, Antonio

2017-01-01

Perceptual decisions requiring the comparison of spatially distributed stimuli that are fixated sequentially might be influenced by fluctuations in visual attention. We used two psychophysical tasks with human subjects to investigate the extent to which visual attention influences simple perceptual choices, and to test the extent to which the attentional Drift Diffusion Model (aDDM) provides a good computational description of how attention affects the underlying decision processes. We find evidence for sizable attentional choice biases and that the aDDM provides a reasonable quantitative description of the relationship between fluctuations in visual attention, choices and reaction times. We also find that exogenous manipulations of attention induce choice biases consistent with the predictions of the model.

Simple control-theoretic models of human steering activity in visually guided vehicle control

NASA Technical Reports Server (NTRS)

Hess, Ronald A.

1991-01-01

A simple control theoretic model of human steering or control activity in the lateral-directional control of vehicles such as automobiles and rotorcraft is discussed. The term 'control theoretic' is used to emphasize the fact that the model is derived from a consideration of well-known control system design principles as opposed to psychological theories regarding egomotion, etc. The model is employed to emphasize the 'closed-loop' nature of tasks involving the visually guided control of vehicles upon, or in close proximity to, the earth and to hypothesize how changes in vehicle dynamics can significantly alter the nature of the visual cues which a human might use in such tasks.

Contribution of intraoperative neuromonitoring to the identification of the external branch of superior laryngeal nerve

PubMed Central

Aygün, Nurcihan; Uludağ, Mehmet; İşgör, Adnan

2017-01-01

Objective We evaluated the contribution of intraoperative neuromonitoring to the visual and functional identification of the external branch of the superior laryngeal nerve. Material and Methods The prospectively collected data of patients who underwent thyroid surgery with intraoperative neuromonitoring for external branch of the superior laryngeal nerve exploration were assessed retrospectively. The surface endotracheal tube-based Medtronic NIM3 intraoperative neuromonitoring device was used. The external branch of the superior laryngeal nerve function was evaluated by the cricothyroid muscle twitch. In addition, contribution of external branch of the superior laryngeal nerve to the vocal cord adduction was evaluated using electromyographic records. Results The study included data of 126 (female, 103; male, 23) patients undergoing thyroid surgery, with a mean age of 46.2±12.2 years (range, 18–75 years), and 215 neck sides were assessed. Two hundred and one (93.5%) of 215 external branch of the superior laryngeal nerves were identified, of which 60 (27.9%) were identified visually before being stimulated with a monopolar stimulator probe. Eighty-nine (41.4%) external branch of the superior laryngeal nerves were identified visually after being identified with a probe. Although 52 (24.1%) external branch of the superior laryngeal nerves were identified with a probe, they were not visualized. Intraoperative neuromonitoring provided a significant contribution to visual (p<0.001) and functional (p<0.001) identification of external branch of the superior laryngeal nerves. Additionally, positive electromyographic responses were recorded from 160 external branch of the superior laryngeal nerves (74.4%). Conclusion Intraoperative neuromonitoring provides an important contribution to visual and functional identification of external branch of the superior laryngeal nerves. We believe that it can not be predicted whether the external branch of the superior laryngeal nerve is at risk or not and the nerve is often invisible; thus, intraoperative neuromonitoring may routinely be used in superior pole dissection. Glottic electromyography response obtained via external branch of the superior laryngeal nerve stimulation provides quantifiable information in addition to the simple visualization of the cricothyroid muscle twitch. PMID:28944328

Suicidality assessment with PRISM-S - simple, fast, and visual: a brief nonverbal method to assess suicidality in adolescent and adult patients.

PubMed

Harbauer, Gregor; Ring, Mariann; Schuetz, Christopher; Andreae, Andreas; Haas, Sebastian

2013-01-01

The PRISM-S task was developed at the Crisis Intervention Center (KIZ) Winterthur, Switzerland, to enable an assessment of the degree of suicidality in less than 5 minutes with a simple, visual instrument. Comparison of validity and clinical use of the new PRISM-S task with other instruments known as "gold standards". Quantitative pilot study enlisting 100 inpatients admitted to the KIZ, aged 15-42 years. Patients' suicidality was assessed by the PRISM-S task during the first clinical interview and compared to data obtained by standardized suicidality instruments. The patients completed the PRISM-S task in 2 to 5 minutes without difficulty. Data show significant positive correlations between the suicidality as assessed by PRISM-S and the gold standards, i.e., DSI-SS (r = 0.59, N = 65, p < .0001). There is no strong evidence that PRISM-S is useful for outpatients or in other settings. The experiences gained with outpatients/patients with other disorders are promising but have not been systematically evaluated. The results do not rely on a randomized design. The sample consists of persons coming to the crisis intervention center. PRISM-S offers a brief, easy-to-administer, and valid method to assess patients' suicidality. The simple instruction facilitates its use in other languages and other cultures as well. The acceptance by patients and health professionals was good, with no one refusing to complete the task.

Compact sensitive instrument for direct ultrasonic visualization of defects.

PubMed

Bar-Cohen, Y; Ben-Joseph, B; Harnik, E

1978-12-01

A simple ultrasonic imaging cell based on the confocal combination of a plano-concave lens and a concave spherical mirror is described. When used in conjunction with a stroboscopic schlieren visualization system, it has the main attributes of a practical nondestructive testing instrument: it is compact, relatively inexpensive, and simple to operate; its sensitivity is fair, resolution and fidelity are good; it has a fairly large field of view and a test piece can be readily scanned. The scope of its applicability is described and discussed.

A Simple Water Channel

ERIC Educational Resources Information Center

White, A. S.

1976-01-01

Describes a simple water channel, for use with an overhead projector. It is run from a water tap and may be used for flow visualization experiments, including the effect of streamlining and elementary building aerodynamics. (MLH)

Differential Distraction Effects in Short-Term and Long-Term Retention of Pictures and Words

ERIC Educational Resources Information Center

Pellegrino, James W.; And Others

1976-01-01

Comparisons between recall levels following simple acoustic or visual tasks and the simultaneous visual-plus-acoustic task are not based upon equivalent amounts of interference within each modality. This research attempts to test more precisely the relationship between visual and acoustic interference by using a sequential rather than a…

Touch Interaction with 3D Geographical Visualization on Web: Selected Technological and User Issues

NASA Astrophysics Data System (ADS)

Herman, L.; Stachoň, Z.; Stuchlík, R.; Hladík, J.; Kubíček, P.

2016-10-01

The use of both 3D visualization and devices with touch displays is increasing. In this paper, we focused on the Web technologies for 3D visualization of spatial data and its interaction via touch screen gestures. At the first stage, we compared the support of touch interaction in selected JavaScript libraries on different hardware (desktop PCs with touch screens, tablets, and smartphones) and software platforms. Afterward, we realized simple empiric test (within-subject design, 6 participants, 2 simple tasks, LCD touch monitor Acer and digital terrain models as stimuli) focusing on the ability of users to solve simple spatial tasks via touch screens. An in-house testing web tool was developed and used based on JavaScript, PHP, and X3DOM languages and Hammer.js libraries. The correctness of answers, speed of users' performances, used gestures, and a simple gesture metric was recorded and analysed. Preliminary results revealed that the pan gesture is most frequently used by test participants and it is also supported by the majority of 3D libraries. Possible gesture metrics and future developments including the interpersonal differences are discussed in the conclusion.

Refractive errors.

PubMed

Schiefer, Ulrich; Kraus, Christina; Baumbach, Peter; Ungewiß, Judith; Michels, Ralf

2016-10-14

All over the world, refractive errors are among the most frequently occuring treatable distur - bances of visual function. Ametropias have a prevalence of nearly 70% among adults in Germany and are thus of great epidemiologic and socio-economic relevance. In the light of their own clinical experience, the authors review pertinent articles retrieved by a selective literature search employing the terms "ametropia, "anisometropia," "refraction," "visual acuity," and epidemiology." In 2011, only 31% of persons over age 16 in Germany did not use any kind of visual aid; 63.4% wore eyeglasses and 5.3% wore contact lenses. Refractive errors were the most common reason for consulting an ophthalmologist, accounting for 21.1% of all outpatient visits. A pinhole aperture (stenopeic slit) is a suitable instrument for the basic diagnostic evaluation of impaired visual function due to optical factors. Spherical refractive errors (myopia and hyperopia), cylindrical refractive errors (astigmatism), unequal refractive errors in the two eyes (anisometropia), and the typical optical disturbance of old age (presbyopia) cause specific functional limitations and can be detected by a physician who does not need to be an ophthalmologist. Simple functional tests can be used in everyday clinical practice to determine quickly, easily, and safely whether the patient is suffering from a benign and easily correctable type of visual impairment, or whether there are other, more serious underlying causes.

Eye movements, visual search and scene memory, in an immersive virtual environment.

PubMed

Kit, Dmitry; Katz, Leor; Sullivan, Brian; Snyder, Kat; Ballard, Dana; Hayhoe, Mary

2014-01-01

Visual memory has been demonstrated to play a role in both visual search and attentional prioritization in natural scenes. However, it has been studied predominantly in experimental paradigms using multiple two-dimensional images. Natural experience, however, entails prolonged immersion in a limited number of three-dimensional environments. The goal of the present experiment was to recreate circumstances comparable to natural visual experience in order to evaluate the role of scene memory in guiding eye movements in a natural environment. Subjects performed a continuous visual-search task within an immersive virtual-reality environment over three days. We found that, similar to two-dimensional contexts, viewers rapidly learn the location of objects in the environment over time, and use spatial memory to guide search. Incidental fixations did not provide obvious benefit to subsequent search, suggesting that semantic contextual cues may often be just as efficient, or that many incidentally fixated items are not held in memory in the absence of a specific task. On the third day of the experience in the environment, previous search items changed in color. These items were fixated upon with increased probability relative to control objects, suggesting that memory-guided prioritization (or Surprise) may be a robust mechanisms for attracting gaze to novel features of natural environments, in addition to task factors and simple spatial saliency.

Perceptual full-reference quality assessment of stereoscopic images by considering binocular visual characteristics.

PubMed

Shao, Feng; Lin, Weisi; Gu, Shanbo; Jiang, Gangyi; Srikanthan, Thambipillai

2013-05-01

Perceptual quality assessment is a challenging issue in 3D signal processing research. It is important to study 3D signal directly instead of studying simple extension of the 2D metrics directly to the 3D case as in some previous studies. In this paper, we propose a new perceptual full-reference quality assessment metric of stereoscopic images by considering the binocular visual characteristics. The major technical contribution of this paper is that the binocular perception and combination properties are considered in quality assessment. To be more specific, we first perform left-right consistency checks and compare matching error between the corresponding pixels in binocular disparity calculation, and classify the stereoscopic images into non-corresponding, binocular fusion, and binocular suppression regions. Also, local phase and local amplitude maps are extracted from the original and distorted stereoscopic images as features in quality assessment. Then, each region is evaluated independently by considering its binocular perception property, and all evaluation results are integrated into an overall score. Besides, a binocular just noticeable difference model is used to reflect the visual sensitivity for the binocular fusion and suppression regions. Experimental results show that compared with the relevant existing metrics, the proposed metric can achieve higher consistency with subjective assessment of stereoscopic images.

Brain State Effects on Layer 4 of the Awake Visual Cortex

PubMed Central

Zhuang, Jun; Bereshpolova, Yulia; Stoelzel, Carl R.; Huff, Joseph M.; Hei, Xiaojuan; Alonso, Jose-Manuel

2014-01-01

Awake mammals can switch between alert and nonalert brain states hundreds of times per day. Here, we study the effects of alertness on two cell classes in layer 4 of primary visual cortex of awake rabbits: presumptive excitatory “simple” cells and presumptive fast-spike inhibitory neurons (suspected inhibitory interneurons). We show that in both cell classes, alertness increases the strength and greatly enhances the reliability of visual responses. In simple cells, alertness also increases the temporal frequency bandwidth, but preserves contrast sensitivity, orientation tuning, and selectivity for direction and spatial frequency. Finally, alertness selectively suppresses the simple cell responses to high-contrast stimuli and stimuli moving orthogonal to the preferred direction, effectively enhancing mid-contrast borders. Using a population coding model, we show that these effects of alertness in simple cells—enhanced reliability, higher gain, and increased suppression in orthogonal orientation—could play a major role at increasing the speed of cortical feature detection. PMID:24623767

Serum Dioxin and Memory Among Veterans of Operation Ranch Hand

DTIC Science & Technology

2007-09-01

logical memory and visual reproductions subtests. In 1987, the WMS-R was published, expanding on the original WMS and creating a more thorough and...the Verbal Paired Associates subtest, the Logical Memory subtest (immediate and delayed recall), and the Visual Reproduction subtest (immediate and...Visual Reproduction subtest, designed to assess visual memory, the veteran was asked to draw from memory four simple geometric designs that were each

A simple visual ethanol biosensor based on alcohol oxidase immobilized onto polyaniline film for halal verification of fermented beverage samples.

PubMed

Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

2014-01-27

A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%-0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification.

MEXPRESS: visualizing expression, DNA methylation and clinical TCGA data.

PubMed

Koch, Alexander; De Meyer, Tim; Jeschke, Jana; Van Criekinge, Wim

2015-08-26

In recent years, increasing amounts of genomic and clinical cancer data have become publically available through large-scale collaborative projects such as The Cancer Genome Atlas (TCGA). However, as long as these datasets are difficult to access and interpret, they are essentially useless for a major part of the research community and their scientific potential will not be fully realized. To address these issues we developed MEXPRESS, a straightforward and easy-to-use web tool for the integration and visualization of the expression, DNA methylation and clinical TCGA data on a single-gene level ( http://mexpress.be ). In comparison to existing tools, MEXPRESS allows researchers to quickly visualize and interpret the different TCGA datasets and their relationships for a single gene, as demonstrated for GSTP1 in prostate adenocarcinoma. We also used MEXPRESS to reveal the differences in the DNA methylation status of the PAM50 marker gene MLPH between the breast cancer subtypes and how these differences were linked to the expression of MPLH. We have created a user-friendly tool for the visualization and interpretation of TCGA data, offering clinical researchers a simple way to evaluate the TCGA data for their genes or candidate biomarkers of interest.

Assessment of a simple obstacle detection device for the visually impaired.

PubMed

Lee, Cheng-Lung; Chen, Chih-Yung; Sung, Peng-Cheng; Lu, Shih-Yi

2014-07-01

A simple obstacle detection device, based upon an automobile parking sensor, was assessed as a mobility aid for the visually impaired. A questionnaire survey for mobility needs was performed at the start of this study. After the detector was developed, five blindfolded sighted and 15 visually impaired participants were invited to conduct travel experiments under three test conditions: (1) using a white cane only, (2) using the obstacle detector only and (3) using both devices. A post-experiment interview regarding the usefulness of the obstacle detector for the visually impaired participants was performed. The results showed that the obstacle detector could augment mobility performance with the white cane. The obstacle detection device should be used in conjunction with the white cane to achieve the best mobility speed and body protection. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Isothermal strand-displacement polymerase reaction for visual detection of the Southeast Asian-type deletion of α-thalassemia.

PubMed

Yu, Luxin; Wu, Wei; Lie, Puchang; Liu, Yunhua; Zeng, Lingwen

2013-11-01

A rapid and reliable screening test for thalassemia carrier couples is the most effective strategy to decrease the risk of conceiving fetuses with severe thalassemia. We present an approach based on the isothermal strand-displacement polymerase reaction and the use of a lateral flow strip for the visual detection of an α-thalassemia Southeast Asian-type deletion. This assay was used to evaluate 86 clinical samples (72 cases of Southeast Asian-type deletions and 14 cases of other types of thalassemia), and the results obtained were 100% consistent with those obtained using conventional gap-PCR. The approach thus provides a simple, sensitive, rapid, and cost-effective method for the diagnosis of thalassemia genotypes. Copyright © 2013 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Reducing breast biopsies by ultrasonographic analysis and a modified self-organizing map

NASA Astrophysics Data System (ADS)

Zheng, Yi; Greenleaf, James F.; Gisvold, John J.

1997-05-01

Recent studies suggest that visual evaluation of ultrasound images could decrease negative biopsies of breast cancer diagnosis. However, visual evaluation requires highly experienced breast sonographers. The objective of this study is to develop computerized radiologist assistant to reduce breast biopsies needed for evaluating suspected breast cancer. The approach of this study utilizes a neural network and tissue features extracted from digital sonographic breast images. The features include texture parameters of breast images: characteristics of echoes within and around breast lesions, and geometrical information of breast tumors. Clusters containing only benign lesions in the feature space are then identified by a modified self- organizing map. This newly developed neural network objectively segments population distributions of lesions and accurately establishes benign and equivocal regions.t eh method was applied to high quality breast sonograms of a large number of patients collected with a controlled procedure at Mayo Clinic. The study showed that the number of biopsies in this group of women could be decreased by 40 percent to 59 percent with high confidence and that no malignancies would have been included in the nonbiopsied group. The advantages of this approach are that it is robust, simple, and effective and does not require highly experienced sonographers.

Webcams as a tool for teaching in Optometry training

NASA Astrophysics Data System (ADS)

Gargallo, A.; Arines, J.

2015-04-01

Clinical Optometry lab training is devoted to develop the students skills needed in eye healthcare professional practice. Nevertheless, students always find difficulties in the management of some optometric instruments and in the understanding of the evaluation techniques. Moreover, teachers also have problems in explaining the eye evaluation tests or making demonstrations of instruments handling. In order to facilitate the learning process, webcams adapted to the optometric devices represent a helpful and useful tool. In this work we present the use of webcams in some of the most common clinical test in Optometry as ocular refraction, colour vision test, eye health evaluation with slip-lamp, retinoscopy, ophthalmoscopy and contact lens fitting. Our experience shows that with this simple approach we can do things easier: show the instrument handling to all the students at the same time; take pictures or videos of different eye health conditions or exploratory routines for posterior visualization with all the students; recreate visual experience of the patient during optometric exam; simulate colour vision pathologies; increase the interactions between students allowing them to help and correct each other; and also record the final routine exam in order to make possible its revision with the students.

Protocol for monitoring standing crop in grasslands using visual obstruction

Treesearch

Lakhdar Benkobi; Daniel W. Uresk; Greg Schenbeck; Rudy M. King

2000-01-01

Assessment of standing crop on grasslands using a visual obstruction technique provides valuable information to help plan livestock grazing management and indicate the status of wildlife habitat. The objectives of this study were to: (1) develop a simple regression model using easily measured visual obstruction to estimate standing crop on sandy lowland range sites in...

Top-Down and Bottom-Up Visual Information Processing of Non-Social Stimuli in High-Functioning Autism Spectrum Disorder

ERIC Educational Resources Information Center

Maekawa, Toshihiko; Tobimatsu, Shozo; Inada, Naoko; Oribe, Naoya; Onitsuka, Toshiaki; Kanba, Shigenobu; Kamio, Yoko

2011-01-01

Individuals with high-functioning autism spectrum disorder (HF-ASD) often show superior performance in simple visual tasks, despite difficulties in the perception of socially important information such as facial expression. The neural basis of visual perception abnormalities associated with HF-ASD is currently unclear. We sought to elucidate the…

Do You "See'" What I "See"? Differentiation of Visual Action Words

ERIC Educational Resources Information Center

Dickinson, Joël; Cirelli, Laura; Szeligo, Frank

2014-01-01

Dickinson and Szeligo ("Can J Exp Psychol" 62(4):211--222, 2008) found that processing time for simple visual stimuli was affected by the visual action participants had been instructed to perform on these stimuli (e.g., see, distinguish). It was concluded that these effects reflected the differences in the durations of these various…

Preparing Content-Rich Learning Environments with VPython and Excel, Controlled by Visual Basic for Applications

ERIC Educational Resources Information Center

Prayaga, Chandra

2008-01-01

A simple interface between VPython and Microsoft (MS) Office products such as Word and Excel, controlled by Visual Basic for Applications, is described. The interface allows the preparation of content-rich, interactive learning environments by taking advantage of the three-dimensional (3D) visualization capabilities of VPython and the GUI…

Correction of Refractive Errors in Rhesus Macaques (Macaca mulatta) Involved in Visual Research

PubMed Central

Mitchell, Jude F; Boisvert, Chantal J; Reuter, Jon D; Reynolds, John H; Leblanc, Mathias

2014-01-01

Macaques are the most common animal model for studies in vision research, and due to their high value as research subjects, often continue to participate in studies well into old age. As is true in humans, visual acuity in macaques is susceptible to refractive errors. Here we report a case study in which an aged macaque demonstrated clear impairment in visual acuity according to performance on a demanding behavioral task. Refraction demonstrated bilateral myopia that significantly affected behavioral and visual tasks. Using corrective lenses, we were able to restore visual acuity. After correction of myopia, the macaque's performance on behavioral tasks was comparable to that of a healthy control. We screened 20 other male macaques to assess the incidence of refractive errors and ocular pathologies in a larger population. Hyperopia was the most frequent ametropia but was mild in all cases. A second macaque had mild myopia and astigmatism in one eye. There were no other pathologies observed on ocular examination. We developed a simple behavioral task that visual research laboratories could use to test visual acuity in macaques. The test was reliable and easily learned by the animals in 1 d. This case study stresses the importance of screening macaques involved in visual science for refractive errors and ocular pathologies to ensure the quality of research; we also provide simple methodology for screening visual acuity in these animals. PMID:25427343

Correction of refractive errors in rhesus macaques (Macaca mulatta) involved in visual research.

PubMed

Mitchell, Jude F; Boisvert, Chantal J; Reuter, Jon D; Reynolds, John H; Leblanc, Mathias

2014-08-01

Macaques are the most common animal model for studies in vision research, and due to their high value as research subjects, often continue to participate in studies well into old age. As is true in humans, visual acuity in macaques is susceptible to refractive errors. Here we report a case study in which an aged macaque demonstrated clear impairment in visual acuity according to performance on a demanding behavioral task. Refraction demonstrated bilateral myopia that significantly affected behavioral and visual tasks. Using corrective lenses, we were able to restore visual acuity. After correction of myopia, the macaque's performance on behavioral tasks was comparable to that of a healthy control. We screened 20 other male macaques to assess the incidence of refractive errors and ocular pathologies in a larger population. Hyperopia was the most frequent ametropia but was mild in all cases. A second macaque had mild myopia and astigmatism in one eye. There were no other pathologies observed on ocular examination. We developed a simple behavioral task that visual research laboratories could use to test visual acuity in macaques. The test was reliable and easily learned by the animals in 1 d. This case study stresses the importance of screening macaques involved in visual science for refractive errors and ocular pathologies to ensure the quality of research; we also provide simple methodology for screening visual acuity in these animals.

An intracellular analysis of the visual responses of neurones in cat visual cortex.

PubMed Central

Douglas, R J; Martin, K A; Whitteridge, D

1991-01-01

1. Extracellular and intracellular recordings were made from neurones in the visual cortex of the cat in order to compare the subthreshold membrane potentials, reflecting the input to the neurone, with the output from the neurone seen as action potentials. 2. Moving bars and edges, generated under computer control, were used to stimulate the neurones. The membrane potential was digitized and averaged for a number of trials after stripping the action potentials. Comparison of extracellular and intracellular discharge patterns indicated that the intracellular impalement did not alter the neurones' properties. Input resistance of the neurone altered little during stable intracellular recordings (30 min-2 h 50 min). 3. Intracellular recordings showed two distinct patterns of membrane potential changes during optimal visual stimulation. The patterns corresponded closely to the division of S-type (simple) and C-type (complex) receptive fields. Simple cells had a complex pattern of membrane potential fluctuations, involving depolarizations alternating with hyperpolarizations. Complex cells had a simple single sustained plateau of depolarization that was often followed but not preceded by a hyperpolarization. In both simple and complex cells the depolarizations led to action potential discharges. The hyperpolarizations were associated with inhibition of action potential discharge. 4. Stimulating simple cells with non-optimal directions of motion produced little or no hyperpolarization of the membrane in most cases, despite a lack of action potential output. Directional complex cells always produced a single plateau of depolarization leading to action potential discharge in both the optimal and non-optimal directions of motion. The directionality could not be predicted on the basis of the position of the hyperpolarizing inhibitory potentials found in the optimal direction. 5. Stimulation of simple cells with non-optimal orientations occasionally produced slight hyperpolarizations and inhibition of action potential discharge. Complex cells, which had broader orientation tuning than simple cells, could show marked hyperpolarization for non-optimal orientations, but this was not generally the case. 6. The data do not support models of directionality and orientation that rely solely on strong inhibitory mechanisms to produce stimulus selectivity. PMID:1804981

Increasing Hand Washing Compliance With a Simple Visual Cue

PubMed Central

Boyer, Brian T.; Menachemi, Nir; Huerta, Timothy R.

2014-01-01

We tested the efficacy of a simple, visual cue to increase hand washing with soap and water. Automated towel dispensers in 8 public bathrooms were set to present a towel either with or without activation by users. We set the 2 modes to operate alternately for 10 weeks. Wireless sensors were used to record entry into bathrooms. Towel and soap consumption rates were checked weekly. There were 97 351 hand-washing opportunities across all restrooms. Towel use was 22.6% higher (P = .05) and soap use was 13.3% higher (P = .003) when the dispenser presented the towel without user activation than when activation was required. Results showed that a visual cue can increase hand-washing compliance in public facilities. PMID:24228670

Stability of simple/complex classification with contrast and extraclassical receptive field modulation in macaque V1

PubMed Central

Henry, Christopher A.

2013-01-01

A key property of neurons in primary visual cortex (V1) is the distinction between simple and complex cells. Recent reports in cat visual cortex indicate the categorization of simple and complex can change depending on stimulus conditions. We investigated the stability of the simple/complex classification with changes in drive produced by either contrast or modulation by the extraclassical receptive field (eCRF). These two conditions were reported to increase the proportion of simple cells in cat cortex. The ratio of the modulation depth of the response (F1) to the elevation of response (F0) to a drifting grating (F1/F0 ratio) was used as the measure of simple/complex. The majority of V1 complex cells remained classified as complex with decreasing contrast. Near contrast threshold, an equal proportion of simple and complex cells changed their classification. The F1/F0 ratio was stable between optimal and large stimulus areas even for those neurons that showed strong eCRF suppression. There was no discernible overall effect of surrounding spatial context on the F1/F0 ratio. Simple/complex cell classification is relatively stable across a range of stimulus drives, produced by either contrast or eCRF suppression. PMID:23303859

Employing Omnidirectional Visual Control for Mobile Robotics.

ERIC Educational Resources Information Center

Wright, J. R., Jr.; Jung, S.; Steplight, S.; Wright, J. R., Sr.; Das, A.

2000-01-01

Describes projects using conventional technologies--incorporation of relatively inexpensive visual control with mobile robots using a simple remote control vehicle platform, a camera, a mirror, and a computer. Explains how technology teachers can apply them in the classroom. (JOW)

A computer model of context-dependent perception in a very simple world

NASA Astrophysics Data System (ADS)

Lara-Dammer, Francisco; Hofstadter, Douglas R.; Goldstone, Robert L.

2017-11-01

We propose the foundations of a computer model of scientific discovery that takes into account certain psychological aspects of human observation of the world. To this end, we simulate two main components of such a system. The first is a dynamic microworld in which physical events take place, and the second is an observer that visually perceives entities and events in the microworld. For reason of space, this paper focuses only on the starting phase of discovery, which is the relatively simple visual inputs of objects and collisions.

Detection and recognition of simple spatial forms

NASA Technical Reports Server (NTRS)

Watson, A. B.

1983-01-01

A model of human visual sensitivity to spatial patterns is constructed. The model predicts the visibility and discriminability of arbitrary two-dimensional monochrome images. The image is analyzed by a large array of linear feature sensors, which differ in spatial frequency, phase, orientation, and position in the visual field. All sensors have one octave frequency bandwidths, and increase in size linearly with eccentricity. Sensor responses are processed by an ideal Bayesian classifier, subject to uncertainty. The performance of the model is compared to that of the human observer in detecting and discriminating some simple images.

Improving lower limb weight distribution asymmetry during the squat using Nintendo Wii Balance Boards and real-time feedback.

PubMed

McGough, Rian; Paterson, Kade; Bradshaw, Elizabeth J; Bryant, Adam L; Clark, Ross A

2012-01-01

Weight-bearing asymmetry (WBA) may be detrimental to performance and could increase the risk of injury; however, detecting and reducing it is difficult in a field setting. This study assessed whether a portable and simple-to-use system designed with multiple Nintendo Wii Balance Boards (NWBBs) and customized software can be used to evaluate and improve WBA. Fifteen elite Australian Rules Footballers and 32 age-matched, untrained participants were tested for measures of WBA while squatting. The NWBB and customized software provided real-time visual feedback of WBA during half of the trials. Outcome measures included the mean mass difference (MMD) between limbs, interlimb symmetry index (SI), and percentage of time spent favoring a single limb (TFSL). Significant reductions in MMD (p = 0.028) and SI (p = 0.007) with visual feedback were observed for the entire group data. Subgroup analysis revealed significant reductions in MMD (p = 0.047) and SI (p = 0.026) with visual feedback in the untrained sample; however, the reductions in the trained sample were nonsignificant. The trained group showed significantly less WBA for TFSL under both visual conditions (no feedback: p = 0.015, feedback: p = 0.017). Correlation analysis revealed that participants with high levels of WBA had the greatest response to feedback (p < 0.001, ρ = 0.557). In conclusion, WBA exists in healthy untrained adults, and these asymmetries can be reduced using real-time visual feedback provided by an NWBB-based system. Healthy, well-trained professional athletes do not possess the same magnitude of WBA. Inexpensive, portable, and widely available gaming technology may be used to evaluate and improve WBA in clinical and sporting settings.

Evaluation and Acceptability of a Simplified Test of Visual Function at Birth in a Limited-Resource Setting.

PubMed

Carrara, Verena I; Darakomon, Mue Chae; Thin, Nant War War; Paw, Naw Ta Kaw; Wah, Naw; Wah, Hser Gay; Helen, Naw; Keereecharoen, Suporn; Paw, Naw Ta Mlar; Jittamala, Podjanee; Nosten, François H; Ricci, Daniela; McGready, Rose

2016-01-01

Neurological examination, including visual fixation and tracking of a target, is routinely performed in the Shoklo Malaria Research Unit postnatal care units on the Thailand-Myanmar border. We aimed to evaluate a simple visual newborn test developed in Italy and performed by non-specialized personnel working in neonatal care units. An intensive training of local health staff in Thailand was conducted prior to performing assessments at 24, 48 and 72 hours of life in healthy, low-risk term singletons. The 48 and 72 hours results were then compared to values obtained to those from Italy. Parents and staff administering the test reported on acceptability. One hundred and seventy nine newborns, between June 2011 and October 2012, participated in the study. The test was rapidly completed if the infant remained in an optimal behavioral stage (7 ± 2 minutes) but the test duration increased significantly (12 ± 4 minutes, p < 0.001) if its behavior changed. Infants were able to fix a target and to discriminate a colored face at 24 hours of life. Horizontal tracking of a target was achieved by 96% (152/159) of the infants at 48 hours. Circular tracking, stripe discrimination and attention to distance significantly improved between each 24-hour test period. The test was easily performed by non-specialized local staff and well accepted by the parents. Healthy term singletons in this limited-resource setting have a visual response similar to that obtained to gestational age matched newborns in Italy. It is possible to use these results as a reference set of values for the visual assessment in Karen and Burmese infants in the first 72 hours of life. The utility of the 24 hours test should be pursued.

The Multisensory Attentional Consequences of Tool Use: A Functional Magnetic Resonance Imaging Study

PubMed Central

Holmes, Nicholas P.; Spence, Charles; Hansen, Peter C.; Mackay, Clare E.; Calvert, Gemma A.

2008-01-01

Background Tool use in humans requires that multisensory information is integrated across different locations, from objects seen to be distant from the hand, but felt indirectly at the hand via the tool. We tested the hypothesis that using a simple tool to perceive vibrotactile stimuli results in the enhanced processing of visual stimuli presented at the distal, functional part of the tool. Such a finding would be consistent with a shift of spatial attention to the location where the tool is used. Methodology/Principal Findings We tested this hypothesis by scanning healthy human participants' brains using functional magnetic resonance imaging, while they used a simple tool to discriminate between target vibrations, accompanied by congruent or incongruent visual distractors, on the same or opposite side to the tool. The attentional hypothesis was supported: BOLD response in occipital cortex, particularly in the right hemisphere lingual gyrus, varied significantly as a function of tool position, increasing contralaterally, and decreasing ipsilaterally to the tool. Furthermore, these modulations occurred despite the fact that participants were repeatedly instructed to ignore the visual stimuli, to respond only to the vibrotactile stimuli, and to maintain visual fixation centrally. In addition, the magnitude of multisensory (visual-vibrotactile) interactions in participants' behavioural responses significantly predicted the BOLD response in occipital cortical areas that were also modulated as a function of both visual stimulus position and tool position. Conclusions/Significance These results show that using a simple tool to locate and to perceive vibrotactile stimuli is accompanied by a shift of spatial attention to the location where the functional part of the tool is used, resulting in enhanced processing of visual stimuli at that location, and decreased processing at other locations. This was most clearly observed in the right hemisphere lingual gyrus. Such modulations of visual processing may reflect the functional importance of visuospatial information during human tool use. PMID:18958150

Factors affecting healing rates after arthroscopic double-row rotator cuff repair.

PubMed

Tashjian, Robert Z; Hollins, Anthony M; Kim, Hyun-Min; Teefey, Sharlene A; Middleton, William D; Steger-May, Karen; Galatz, Leesa M; Yamaguchi, Ken

2010-12-01

Double-row arthroscopic rotator cuff repairs were developed to improve initial biomechanical strength of repairs to improve healing rates. Despite biomechanical improvements, failure of healing remains a clinical problem. To evaluate the anatomical results after double-row arthroscopic rotator cuff repair with ultrasound to determine postoperative repair integrity and the effect of various factors on tendon healing. Case series; Level of evidence, 4. Forty-eight patients (49 shoulders) who had a complete arthroscopic rotator cuff repair (double-row technique) were evaluated with ultrasound at a minimum of 6 months after surgery. Outcome was evaluated at a minimum of 1-year follow-up with standardized history and physical examination, visual analog scale for pain, active forward elevation, and preoperative and postoperative shoulder scores according to the system of the American Shoulder and Elbow Surgeons and the Simple Shoulder Test. Quantitative strength was measured postoperatively. Ultrasound and physical examinations were performed at a minimum of 6 months after surgery (mean, 16 months; range, 6 to 36 months) and outcome questionnaire evaluations at a minimum of 12 months after surgery (mean, 29 months; range, 12 to 55 months). Of 49 repairs, 25 (51%) were healed. Healing rates were 67% in single-tendon tears (16 of 24 shoulders) and 36% in multitendon tears (9 of 25 shoulders). Older age and longer duration of follow-up were correlated with poorer tendon healing (P < .03). Visual analog scale for pain, active forward elevation, American Shoulder and Elbow Surgeons scores, and Simple Shoulder Test scores all had significant improvement from baseline after repair (P < .0001). Increased age and longer duration of follow-up were associated with lower healing rates after double-row rotator cuff repair. The biological limitation at the repair site, as reflected by the effects of age on healing, appears to be the most important factor influencing tendon healing, even after maximizing repair biomechanical strength with a double-row construct.

VISUAL DATA MINING IN ATMOSPHERIC SCIENCE DATA

EPA Science Inventory

This paper discusses the use of simple visual tools to explore multivariate spatially-referenced data. It describes interactive approaches such as linked brushing, and dynamic methods such as the grand tour. applied to studying the Comprehensive Ocean-Atmosphere Data Set (COADS)....

Elderly Healthcare Monitoring Using an Avatar-Based 3D Virtual Environment

PubMed Central

Pouke, Matti; Häkkilä, Jonna

2013-01-01

Homecare systems for elderly people are becoming increasingly important due to both economic reasons as well as patients’ preferences. Sensor-based surveillance technologies are an expected future trend, but research so far has devoted little attention to the User Interface (UI) design of such systems and the user-centric design approach. In this paper, we explore the possibilities of an avatar-based 3D visualization system, which exploits wearable sensors and human activity simulations. We present a technical prototype and the evaluation of alternative concept designs for UIs based on a 3D virtual world. The evaluation was conducted with homecare providers through focus groups and an online survey. Our results show firstly that systems taking advantage of 3D virtual world visualization techniques have potential especially due to the privacy preserving and simplified information presentation style, and secondly that simple representations and glancability should be emphasized in the design. The identified key use cases highlight that avatar-based 3D presentations can be helpful if they provide an overview as well as details on demand. PMID:24351747

Influence of social presence on eye movements in visual search tasks.

PubMed

Liu, Na; Yu, Ruifeng

2017-12-01

This study employed an eye-tracking technique to investigate the influence of social presence on eye movements in visual search tasks. A total of 20 male subjects performed visual search tasks in a 2 (target presence: present vs. absent) × 2 (task complexity: complex vs. simple) × 2 (social presence: alone vs. a human audience) within-subject experiment. Results indicated that the presence of an audience could evoke a social facilitation effect on response time in visual search tasks. Compared with working alone, the participants made fewer and shorter fixations, larger saccades and shorter scan path in simple search tasks and more and longer fixations, smaller saccades and longer scan path in complex search tasks when working with an audience. The saccade velocity and pupil diameter in the audience-present condition were larger than those in the working-alone condition. No significant change in target fixation number was observed between two social presence conditions. Practitioner Summary: This study employed an eye-tracking technique to examine the influence of social presence on eye movements in visual search tasks. Results clarified the variation mechanism and characteristics of oculomotor scanning induced by social presence in visual search.

Beauty and the beholder: the role of visual sensitivity in visual preference

PubMed Central

Spehar, Branka; Wong, Solomon; van de Klundert, Sarah; Lui, Jessie; Clifford, Colin W. G.; Taylor, Richard P.

2015-01-01

For centuries, the essence of aesthetic experience has remained one of the most intriguing mysteries for philosophers, artists, art historians and scientists alike. Recently, views emphasizing the link between aesthetics, perception and brain function have become increasingly prevalent (Ramachandran and Hirstein, 1999; Zeki, 1999; Livingstone, 2002; Ishizu and Zeki, 2013). The link between art and the fractal-like structure of natural images has also been highlighted (Spehar et al., 2003; Graham and Field, 2007; Graham and Redies, 2010). Motivated by these claims and our previous findings that humans display a consistent preference across various images with fractal-like statistics, here we explore the possibility that observers’ preference for visual patterns might be related to their sensitivity for such patterns. We measure sensitivity to simple visual patterns (sine-wave gratings varying in spatial frequency and random textures with varying scaling exponent) and find that they are highly correlated with visual preferences exhibited by the same observers. Although we do not attempt to offer a comprehensive neural model of aesthetic experience, we demonstrate a strong relationship between visual sensitivity and preference for simple visual patterns. Broadly speaking, our results support assertions that there is a close relationship between aesthetic experience and the sensory coding of natural stimuli. PMID:26441611

Developing measures of fatigue using an alcohol comparison to validate the effects of fatigue on performance.

PubMed

Williamson, A M; Feyer, A M; Mattick, R P; Friswell, R; Finlay-Brown, S

2001-05-01

The effects of 28 h of sleep deprivation were compared with varying doses of alcohol up to 0.1% blood alcohol concentration (BAC) in the same subjects. The study was conducted in the laboratory. Twenty long-haul truck drivers and 19 people not employed as professional drivers acted as subjects. Tests were selected that were likely to be affected by fatigue, including simple reaction time, unstable tracking, dual task, Mackworth clock vigilance test, symbol digit coding, visual search, sequential spatial memory and logical reasoning. While performance effects were seen due to alcohol for all tests, sleep deprivation affected performance on most tests, but had no effect on performance on the visual search and logical reasoning tests. Some tests showed evidence of a circadian rhythm effect on performance, in particular, simple reaction time, dual task, Mackworth clock vigilance, and symbol digit coding, but only for response speed and not response accuracy. Drivers were slower but more accurate than controls on the symbol digit test, suggesting that they took a more conservative approach to performance of this test. This study demonstrated which tests are most sensitive to sleep deprivation and fatigue. The study therefore has established a set of tests that can be used in evaluations of fatigue and fatigue countermeasures.

Lack of sex effect on brain activity during a visuomotor response task: functional MR imaging study.

PubMed

Mikhelashvili-Browner, Nina; Yousem, David M; Wu, Colin; Kraut, Michael A; Vaughan, Christina L; Oguz, Kader Karli; Calhoun, Vince D

2003-03-01

As more individuals are enrolled in clinical functional MR imaging (fMRI) studies, an understanding of how sex may influence fMRI-measured brain activation is critical. We used fixed- and random-effects models to study the influence of sex on fMRI patterns of brain activation during a simple visuomotor reaction time task in the group of 26 age-matched men and women. We evaluated the right visual, left visual, left primary motor, left supplementary motor, and left anterior cingulate areas. Volumes of activations did not significantly differ between the groups in any defined regions. Analysis of variance failed to show any significant correlations between sex and volumes of brain activation in any location studied. Mean percentage signal-intensity changes for all locations were similar between men and women. A two-way t test of brain activation in men and women, performed as a part of random-effects modeling, showed no significant difference at any site. Our results suggest that sex seems to have little influence on fMRI brain activation when we compared performance on the simple reaction-time task. The need to control for sex effects is not critical in the analysis of this task with fMRI.

Visualizing Sound Directivity via Smartphone Sensors

NASA Astrophysics Data System (ADS)

Hawley, Scott H.; McClain, Robert E.

2018-02-01

When Yang-Hann Kim received the Rossing Prize in Acoustics Education at the 2015 meeting of the Acoustical Society of America, he stressed the importance of offering visual depictions of sound fields when teaching acoustics. Often visualization methods require specialized equipment such as microphone arrays or scanning apparatus. We present a simple method for visualizing angular dependence in sound fields, made possible via the confluence of sensors available via a new smartphone app that the authors have developed.

Neural Responses in Parietal and Occipital Areas in Response to Visual Events Are Modulated by Prior Multisensory Stimuli

PubMed Central

Innes-Brown, Hamish; Barutchu, Ayla; Crewther, David P.

2013-01-01

The effect of multi-modal vs uni-modal prior stimuli on the subsequent processing of a simple flash stimulus was studied in the context of the audio-visual ‘flash-beep’ illusion, in which the number of flashes a person sees is influenced by accompanying beep stimuli. EEG recordings were made while combinations of simple visual and audio-visual stimuli were presented. The experiments found that the electric field strength related to a flash stimulus was stronger when it was preceded by a multi-modal flash/beep stimulus, compared to when it was preceded by another uni-modal flash stimulus. This difference was found to be significant in two distinct timeframes – an early timeframe, from 130–160 ms, and a late timeframe, from 300–320 ms. Source localisation analysis found that the increased activity in the early interval was localised to an area centred on the inferior and superior parietal lobes, whereas the later increase was associated with stronger activity in an area centred on primary and secondary visual cortex, in the occipital lobe. The results suggest that processing of a visual stimulus can be affected by the presence of an immediately prior multisensory event. Relatively long-lasting interactions generated by the initial auditory and visual stimuli altered the processing of a subsequent visual stimulus. PMID:24391939

A Simple Visual Ethanol Biosensor Based on Alcohol Oxidase Immobilized onto Polyaniline Film for Halal Verification of Fermented Beverage Samples

PubMed Central

Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

2014-01-01

A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%–0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification. PMID:24473284

Rocker: Open source, easy-to-use tool for AUC and enrichment calculations and ROC visualization.

PubMed

Lätti, Sakari; Niinivehmas, Sanna; Pentikäinen, Olli T

2016-01-01

Receiver operating characteristics (ROC) curve with the calculation of area under curve (AUC) is a useful tool to evaluate the performance of biomedical and chemoinformatics data. For example, in virtual drug screening ROC curves are very often used to visualize the efficiency of the used application to separate active ligands from inactive molecules. Unfortunately, most of the available tools for ROC analysis are implemented into commercially available software packages, or are plugins in statistical software, which are not always the easiest to use. Here, we present Rocker, a simple ROC curve visualization tool that can be used for the generation of publication quality images. Rocker also includes an automatic calculation of the AUC for the ROC curve and Boltzmann-enhanced discrimination of ROC (BEDROC). Furthermore, in virtual screening campaigns it is often important to understand the early enrichment of active ligand identification, for this Rocker offers automated calculation routine. To enable further development of Rocker, it is freely available (MIT-GPL license) for use and modifications from our web-site (http://www.jyu.fi/rocker).

ViSimpl: Multi-View Visual Analysis of Brain Simulation Data

PubMed Central

Galindo, Sergio E.; Toharia, Pablo; Robles, Oscar D.; Pastor, Luis

2016-01-01

After decades of independent morphological and functional brain research, a key point in neuroscience nowadays is to understand the combined relationships between the structure of the brain and its components and their dynamics on multiple scales, ranging from circuits of neurons at micro or mesoscale to brain regions at macroscale. With such a goal in mind, there is a vast amount of research focusing on modeling and simulating activity within neuronal structures, and these simulations generate large and complex datasets which have to be analyzed in order to gain the desired insight. In such context, this paper presents ViSimpl, which integrates a set of visualization and interaction tools that provide a semantic view of brain data with the aim of improving its analysis procedures. ViSimpl provides 3D particle-based rendering that allows visualizing simulation data with their associated spatial and temporal information, enhancing the knowledge extraction process. It also provides abstract representations of the time-varying magnitudes supporting different data aggregation and disaggregation operations and giving also focus and context clues. In addition, ViSimpl tools provide synchronized playback control of the simulation being analyzed. Finally, ViSimpl allows performing selection and filtering operations relying on an application called NeuroScheme. All these views are loosely coupled and can be used independently, but they can also work together as linked views, both in centralized and distributed computing environments, enhancing the data exploration and analysis procedures. PMID:27774062

ViSimpl: Multi-View Visual Analysis of Brain Simulation Data.

PubMed

Galindo, Sergio E; Toharia, Pablo; Robles, Oscar D; Pastor, Luis

2016-01-01

After decades of independent morphological and functional brain research, a key point in neuroscience nowadays is to understand the combined relationships between the structure of the brain and its components and their dynamics on multiple scales, ranging from circuits of neurons at micro or mesoscale to brain regions at macroscale. With such a goal in mind, there is a vast amount of research focusing on modeling and simulating activity within neuronal structures, and these simulations generate large and complex datasets which have to be analyzed in order to gain the desired insight. In such context, this paper presents ViSimpl, which integrates a set of visualization and interaction tools that provide a semantic view of brain data with the aim of improving its analysis procedures. ViSimpl provides 3D particle-based rendering that allows visualizing simulation data with their associated spatial and temporal information, enhancing the knowledge extraction process. It also provides abstract representations of the time-varying magnitudes supporting different data aggregation and disaggregation operations and giving also focus and context clues. In addition, ViSimpl tools provide synchronized playback control of the simulation being analyzed. Finally, ViSimpl allows performing selection and filtering operations relying on an application called NeuroScheme. All these views are loosely coupled and can be used independently, but they can also work together as linked views, both in centralized and distributed computing environments, enhancing the data exploration and analysis procedures.

Chemical Instrumentation for the Visually Handicapped.

ERIC Educational Resources Information Center

Anderson, James L.

1982-01-01

Describes a simple, relatively inexpensive, and easily implemented approach for introducing visually handicapped students to chemical instrumentation via experiments on operational amplifiers as examples of some of the electronic building blocks of chemical instrumentation. The approach is applicable to other chemical instruments having electrical…

Pilot/vehicle model analysis of visually guided flight

NASA Technical Reports Server (NTRS)

Zacharias, Greg L.

1991-01-01

Information is given in graphical and outline form on a pilot/vehicle model description, control of altitude with simple terrain clues, simulated flight with visual scene delays, model-based in-cockpit display design, and some thoughts on the role of pilot/vehicle modeling.

A Tiered Approach to Evaluating Salinity Sources in Water at Oil and Gas Production Sites.

PubMed

Paquette, Shawn M; Molofsky, Lisa J; Connor, John A; Walker, Kenneth L; Hopkins, Harley; Chakraborty, Ayan

2017-09-01

A suspected increase in the salinity of fresh water resources can trigger a site investigation to identify the source(s) of salinity and the extent of any impacts. These investigations can be complicated by the presence of naturally elevated total dissolved solids or chlorides concentrations, multiple potential sources of salinity, and incomplete data and information on both naturally occurring conditions and the characteristics of potential sources. As a result, data evaluation techniques that are effective at one site may not be effective at another. In order to match the complexity of the evaluation effort to the complexity of the specific site, this paper presents a strategic tiered approach that utilizes established techniques for evaluating and identifying the source(s) of salinity in an efficient step-by-step manner. The tiered approach includes: (1) a simple screening process to evaluate whether an impact has occurred and if the source is readily apparent; (2) basic geochemical characterization of the impacted water resource(s) and potential salinity sources coupled with simple visual and statistical data evaluation methods to determine the source(s); and (3) advanced laboratory analyses (e.g., isotopes) and data evaluation methods to identify the source(s) and the extent of salinity impacts where it was not otherwise conclusive. A case study from the U.S. Gulf Coast is presented to illustrate the application of this tiered approach. © 2017, National Ground Water Association.

Factors influencing visual rehabilitation after occlusion therapy in unilateral amblyopia in children.

PubMed

Menon, Vimla; Chaudhuri, Zia; Saxena, Rohit; Gill, Kulwant; Sachdeva, M M

2005-12-01

Amblyopia is one of the most common causes of visual impairment in adults and children, and visual loss may be permanent if not treated in time. Though many studies have been done on occlusion therapy which is the mainstay in the treatment of unilateral amblyopia, discrepancies exist in literature about quantification of treatment and follow up measures. The present study was undertaken to evaluate the factors responsible for the successful outcome of treatment and the optimum time required for the same in children with unilateral amblyopia. Baseline characteristics of 63 verbal patients with unilateral amblyopia (strabismic, anisometropic, mixed) referred to the Strabismus and Amblyopia Clinic at the Dr Rajendra Prasad Centre for Ophthalmic Sciences, New Delhi between September 2001 to December 2002 who improved to the desired level of visual acuity after treatment for amblyopia in the mentioned time period, were analyzed to assess for factors that directly or indirectly influenced the optimum visual rehabilitation and the average duration of therapy required for the same. The evaluation included assessment of the baseline best-corrected visual acuity (BCVA) and refractive status in both eyes, the age at presentation, the type of amblyopia present, fixation pattern in the amblyopic eye, inter-eye visual acuity difference, and evaluation of compliance through a parental diary system. Baseline BCVA in the amblyopic eye was similar in all the three groups. Patients with anisometropic amblyopia showed a quicker response to therapy. Compliance to treatment was the major factor affecting the overall time required for a successful outcome in most cases. The overall time required for the treatment to be successful (including the period of maintenance) was about 1,089 h. This hospital-based study showed that the average duration of occlusion therapy to achieve stable isoacuity was 7.2 months with an average occlusion of 6-7 h/day. Compliance to therapy was the most important factor affecting the duration of therapy. With increasing emphasis on paediatric eye diseases, amblyopia is at last getting its due importance as a cause of treatable correctable paediatric visual impairment which can have lifelong repercussions, both in terms of individual disability and financial burden to the society if not treated in time. As the therapy is simple and effective if started early, mass awareness, visual screening, and counselling would go a long way in treating the patients, thus decreasing the prevalence of amblyopia in the country.

Red square test for visual field screening. A sensitive and simple bedside test.

PubMed

Mandahl, A

1994-12-01

A reliable bedside test for screening of visual field defects is a valuable tool in the examination of patients with a putative disease affecting the sensory visual pathways. Conventional methods such as Donders' confrontation method, counting fingers in the visual field periphery, of two-hand confrontation are not sufficiently sensitive to detect minor but nevertheless serious visual field defects. More sensitive methods requiring only simple tools are also described. In this study, a test card with four red squares surrounding a fixation target, a black dot, with a total test area of about 11 x 12.5 degrees at a distance of 30 cm, was designed for testing experience of red colour saturation in four quadrants, red square test. The Goldmann visual field was used as reference. 125 consecutive patients with pituitary adenoma (159 eyes), craniopharyngeoma (9 eyes), meningeoma (21 eyes), vascular hemisphere lesion (40 eyes), hemisphere tumour (10 eyes) and hemisphere abscess (2 eyes) were examined. The Goldmann visual field and red square test were pathological in pituitary adenomas in 35%, in craniopharyngeomas in 44%, in meningeomas in 52% and in hemisphere tumours or abscess in 100% of the eyes. Among these, no false-normal or false-pathological tests were found. However, in vascular hemisphere disease the corresponding figures were Goldmann visual field 90% and red square test 85%. The 5% difference (4 eyes) was due to Goldmann visual field defects strictly peripheral to the central 15 degrees. These defects were easily diagnosed with two-hand confrontation and

Visual artificial grammar learning: comparative research on humans, kea (Nestor notabilis) and pigeons (Columba livia)

PubMed Central

Stobbe, Nina; Westphal-Fitch, Gesche; Aust, Ulrike; Fitch, W. Tecumseh

2012-01-01

Artificial grammar learning (AGL) provides a useful tool for exploring rule learning strategies linked to general purpose pattern perception. To be able to directly compare performance of humans with other species with different memory capacities, we developed an AGL task in the visual domain. Presenting entire visual patterns simultaneously instead of sequentially minimizes the amount of required working memory. This approach allowed us to evaluate performance levels of two bird species, kea (Nestor notabilis) and pigeons (Columba livia), in direct comparison to human participants. After being trained to discriminate between two types of visual patterns generated by rules at different levels of computational complexity and presented on a computer screen, birds and humans received further training with a series of novel stimuli that followed the same rules, but differed in various visual features from the training stimuli. Most avian and all human subjects continued to perform well above chance during this initial generalization phase, suggesting that they were able to generalize learned rules to novel stimuli. However, detailed testing with stimuli that violated the intended rules regarding the exact number of stimulus elements indicates that neither bird species was able to successfully acquire the intended pattern rule. Our data suggest that, in contrast to humans, these birds were unable to master a simple rule above the finite-state level, even with simultaneous item presentation and despite intensive training. PMID:22688635

The Pareidolia Test: A Simple Neuropsychological Test Measuring Visual Hallucination-Like Illusions.

PubMed

Mamiya, Yasuyuki; Nishio, Yoshiyuki; Watanabe, Hiroyuki; Yokoi, Kayoko; Uchiyama, Makoto; Baba, Toru; Iizuka, Osamu; Kanno, Shigenori; Kamimura, Naoto; Kazui, Hiroaki; Hashimoto, Mamoru; Ikeda, Manabu; Takeshita, Chieko; Shimomura, Tatsuo; Mori, Etsuro

2016-01-01

Visual hallucinations are a core clinical feature of dementia with Lewy bodies (DLB), and this symptom is important in the differential diagnosis and prediction of treatment response. The pareidolia test is a tool that evokes visual hallucination-like illusions, and these illusions may be a surrogate marker of visual hallucinations in DLB. We created a simplified version of the pareidolia test and examined its validity and reliability to establish the clinical utility of this test. The pareidolia test was administered to 52 patients with DLB, 52 patients with Alzheimer's disease (AD) and 20 healthy controls (HCs). We assessed the test-retest/inter-rater reliability using the intra-class correlation coefficient (ICC) and the concurrent validity using the Neuropsychiatric Inventory (NPI) hallucinations score as a reference. A receiver operating characteristic (ROC) analysis was used to evaluate the sensitivity and specificity of the pareidolia test to differentiate DLB from AD and HCs. The pareidolia test required approximately 15 minutes to administer, exhibited good test-retest/inter-rater reliability (ICC of 0.82), and moderately correlated with the NPI hallucinations score (rs = 0.42). Using an optimal cut-off score set according to the ROC analysis, and the pareidolia test differentiated DLB from AD with a sensitivity of 81% and a specificity of 92%. Our study suggests that the simplified version of the pareidolia test is a valid and reliable surrogate marker of visual hallucinations in DLB.

Eye Movements, Visual Search and Scene Memory, in an Immersive Virtual Environment

PubMed Central

Sullivan, Brian; Snyder, Kat; Ballard, Dana; Hayhoe, Mary

2014-01-01

Visual memory has been demonstrated to play a role in both visual search and attentional prioritization in natural scenes. However, it has been studied predominantly in experimental paradigms using multiple two-dimensional images. Natural experience, however, entails prolonged immersion in a limited number of three-dimensional environments. The goal of the present experiment was to recreate circumstances comparable to natural visual experience in order to evaluate the role of scene memory in guiding eye movements in a natural environment. Subjects performed a continuous visual-search task within an immersive virtual-reality environment over three days. We found that, similar to two-dimensional contexts, viewers rapidly learn the location of objects in the environment over time, and use spatial memory to guide search. Incidental fixations did not provide obvious benefit to subsequent search, suggesting that semantic contextual cues may often be just as efficient, or that many incidentally fixated items are not held in memory in the absence of a specific task. On the third day of the experience in the environment, previous search items changed in color. These items were fixated upon with increased probability relative to control objects, suggesting that memory-guided prioritization (or Surprise) may be a robust mechanisms for attracting gaze to novel features of natural environments, in addition to task factors and simple spatial saliency. PMID:24759905

Visualization of decision processes using a cognitive architecture

NASA Astrophysics Data System (ADS)

Livingston, Mark A.; Murugesan, Arthi; Brock, Derek; Frost, Wende K.; Perzanowski, Dennis

2013-01-01

Cognitive architectures are computational theories of reasoning the human mind engages in as it processes facts and experiences. A cognitive architecture uses declarative and procedural knowledge to represent mental constructs that are involved in decision making. Employing a model of behavioral and perceptual constraints derived from a set of one or more scenarios, the architecture reasons about the most likely consequence(s) of a sequence of events. Reasoning of any complexity and depth involving computational processes, however, is often opaque and challenging to comprehend. Arguably, for decision makers who may need to evaluate or question the results of autonomous reasoning, it would be useful to be able to inspect the steps involved in an interactive, graphical format. When a chain of evidence and constraint-based decision points can be visualized, it becomes easier to explore both how and why a scenario of interest will likely unfold in a particular way. In initial work on a scheme for visualizing cognitively-based decision processes, we focus on generating graphical representations of models run in the Polyscheme cognitive architecture. Our visualization algorithm operates on a modified version of Polyscheme's output, which is accomplished by augmenting models with a simple set of tags. We provide example visualizations and discuss properties of our technique that pose challenges for our representation goals. We conclude with a summary of feedback solicited from domain experts and practitioners in the field of cognitive modeling.

Initial flight and simulator evaluation of a head up display for standard and noise abatement visual approaches

NASA Technical Reports Server (NTRS)

Bourquin, K.; Palmer, E. A.; Cooper, G.; Gerdes, R. M.

1973-01-01

A preliminary assessment was made of the adequacy of a simple head up display (HUD) for providing vertical guidance for flying noise abatement and standard visual approaches in a jet transport. The HUD featured gyro-stabilized approach angle scales which display the angle of declination to any point on the ground and a horizontal flight path bar which aids the pilot in his control of the aircraft flight path angle. Thirty-three standard and noise abatement approaches were flown in a Boeing 747 aircraft equipped with a head up display. The HUD was also simulated in a research simulator. The simulator was used to familiarize the pilots with the display and to determine the most suitable way to use the HUD for making high capture noise abatement approaches. Preliminary flight and simulator data are presented and problem areas that require further investigation are identified.

The efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment.

PubMed

Jang, Ji Hye; Kim, Yu Cheol; Kim, Kwang Soo

2009-12-01

This study was designed to evaluate the efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment. We retrospectively reviewed the records of 33 consecutive patients (35 eyes) who underwent fluid-gas exchange treatment for postvitrectomy retinal detachment using the two-needle pars plana approach technique. The retinal reattachment rate was 80.0% after complete intravitreal gas disappearance following the fluid-gas exchange; the overall success rate was 65.7%. Visual acuity was improved or stable in 80.0% of cases; a two-line or greater vision improvement or a best-corrected visual acuity of 0.4 or better occurred in 62.9% of cases. The success rates for superior retinal detachments and posterior pole retinal detachments were 76.5% and 85.7%, respectively. Fluid-gas exchange represents a simple and cost-effective alternative outpatient procedure for retinal reattachment without reoperation for the treatment of superior and posterior pole retinal detachments.

A new approach of data clustering using a flock of agents.

PubMed

Picarougne, Fabien; Azzag, Hanene; Venturini, Gilles; Guinot, Christiane

2007-01-01

This paper presents a new bio-inspired algorithm (FClust) that dynamically creates and visualizes groups of data. This algorithm uses the concepts of a flock of agents that move together in a complex manner with simple local rules. Each agent represents one data. The agents move together in a 2D environment with the aim of creating homogeneous groups of data. These groups are visualized in real time, and help the domain expert to understand the underlying structure of the data set, like for example a realistic number of classes, clusters of similar data, isolated data. We also present several extensions of this algorithm, which reduce its computational cost, and make use of a 3D display. This algorithm is then tested on artificial and real-world data, and a heuristic algorithm is used to evaluate the relevance of the obtained partitioning.

Integration of Real-Time Intraoperative Contrast-Enhanced Ultrasound and Color Doppler Ultrasound in the Surgical Treatment of Spinal Cord Dural Arteriovenous Fistulas.

PubMed

Della Pepa, Giuseppe Maria; Sabatino, Giovanni; Sturiale, Carmelo Lucio; Marchese, Enrico; Puca, Alfredo; Olivi, Alessandro; Albanese, Alessio

2018-04-01

In the surgical treatment of spinal dural arteriovenous fistulas (DAVFs), intraoperative definition of anatomic characteristics of the DAVF and identification of the fistulous point is mandatory to effectively exclude the DAVF. Intraoperative ultrasound and contrast-enhanced ultrasound integrated with color Doppler ultrasound was applied in the surgical setting for a cervical DAVF to identify the fistulous point and evaluate correct occlusion of the fistula. Integration of intraoperative ultrasound and contrast-enhanced ultrasound is a simple, cost-effective technique that provides an opportunity for real-time dynamic visualization of DAVF vascular patterns, identification of the fistulous point, and assessment of correct exclusion. Compared with other intraoperative tools, such as indocyanine green videoangiography, it allows the surgeon to visualize hidden anatomic and vascular structures, minimizing surgical manipulation and guiding the surgeon during resection. Copyright © 2018 Elsevier Inc. All rights reserved.

Rapid and accurate diagnosis of acute cholecystitis with /sup 99m/Tc-HIDA cholescintigraphy. [HIDA = dimethyl acetanilide iminodiacetic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weissmann, H.S.; Frank, M.S.; Bernstein, L.H.

1979-04-01

Technetium-99m dimethyl acetanilide iminodiacetic acid (HIDA) cholescintigraphy was performed on 90 patients with suspected acute cholecytitis. Visualization of the gallbladder established patency of the cystic duct and excluded the diagnosis of acute cholecystitis in 50 of 52 patients. Nonvisualization of the gallbladder with visualization of the common bile duct was diagnostic of acute cholecystitis in 38 patients, all subsequently proven at surgery. The observed accuracy of this procedure is 98% and specificity is 100%. The false negative rate is 5% and false positive rate is zero. Technetium-99m-HILDA has many advantages which make it the procedure of choice in evaluating amore » patient for suspected acute cholecystitis. It is a rapid, simple, safe examination which provides functional as well as anatomic information about the hepatobiliary system in individuals with a serum bilirubin level up to 8 mg/100 ml.« less

AdjScales: Visualizing Differences between Adjectives for Language Learners

NASA Astrophysics Data System (ADS)

Sheinman, Vera; Tokunaga, Takenobu

In this study we introduce AdjScales, a method for scaling similar adjectives by their strength. It combines existing Web-based computational linguistic techniques in order to automatically differentiate between similar adjectives that describe the same property by strength. Though this kind of information is rarely present in most of the lexical resources and dictionaries, it may be useful for language learners that try to distinguish between similar words. Additionally, learners might gain from a simple visualization of these differences using unidimensional scales. The method is evaluated by comparison with annotation on a subset of adjectives from WordNet by four native English speakers. It is also compared against two non-native speakers of English. The collected annotation is an interesting resource in its own right. This work is a first step toward automatic differentiation of meaning between similar words for language learners. AdjScales can be useful for lexical resource enhancement.

A Simple Classroom Demonstration of Natural Convection

ERIC Educational Resources Information Center

Wheeler, Dean R.

2005-01-01

This article explains a simple way to demonstrate natural convection, such as from a lit candle, in the classroom using an overhead projector. The demonstration is based on the principle of schlieren imaging, commonly used to visualize variations in density for gas flows.

A Rotatable Quality Control Phantom for Evaluating the Performance of Flat Panel Detectors in Imaging Moving Objects.

PubMed

Haga, Yoshihiro; Chida, Koichi; Inaba, Yohei; Kaga, Yuji; Meguro, Taiichiro; Zuguchi, Masayuki

2016-02-01

As the use of diagnostic X-ray equipment with flat panel detectors (FPDs) has increased, so has the importance of proper management of FPD systems. To ensure quality control (QC) of FPD system, an easy method for evaluating FPD imaging performance for both stationary and moving objects is required. Until now, simple rotatable QC phantoms have not been available for the easy evaluation of the performance (spatial resolution and dynamic range) of FPD in imaging moving objects. We developed a QC phantom for this purpose. It consists of three thicknesses of copper and a rotatable test pattern of piano wires of various diameters. Initial tests confirmed its stable performance. Our moving phantom is very useful for QC of FPD images of moving objects because it enables visual evaluation of image performance (spatial resolution and dynamic range) easily.

The Effects of Visual Complexity for Japanese Kanji Processing with High and Low Frequencies

ERIC Educational Resources Information Center

Tamaoka, Katsuo; Kiyama, Sachiko

2013-01-01

The present study investigated the effects of visual complexity for kanji processing by selecting target kanji from different stroke ranges of visually simple (2-6 strokes), medium (8-12 strokes), and complex (14-20 strokes) kanji with high and low frequencies. A kanji lexical decision task in Experiment 1 and a kanji naming task in Experiment 2…

Emerging category representation in the visual forebrain hierarchy of pigeons (Columba livia).

PubMed

Azizi, Amir Hossein; Pusch, Roland; Koenen, Charlotte; Klatt, Sebastian; Bröcker, Franziska; Thiele, Samuel; Kellermann, Janosch; Güntürkün, Onur; Cheng, Sen

2018-06-06

Recognizing and categorizing visual stimuli are cognitive functions vital for survival, and an important feature of visual systems in primates as well as in birds. Visual stimuli are processed along the ventral visual pathway. At every stage in the hierarchy, neurons respond selectively to more complex features, transforming the population representation of the stimuli. It is therefore easier to read-out category information in higher visual areas. While explicit category representations have been observed in the primate brain, less is known on equivalent processes in the avian brain. Even though their brain anatomies are radically different, it has been hypothesized that visual object representations are comparable across mammals and birds. In the present study, we investigated category representations in the pigeon visual forebrain using recordings from single cells responding to photographs of real-world objects. Using a linear classifier, we found that the population activity in the visual associative area mesopallium ventrolaterale (MVL) distinguishes between animate and inanimate objects, although this distinction is not required by the task. By contrast, a population of cells in the entopallium, a region that is lower in the hierarchy of visual areas and that is related to the primate extrastriate cortex, lacked this information. A model that pools responses of simple cells, which function as edge detectors, can account for the animate vs. inanimate categorization in the MVL, but performance in the model is based on different features than in MVL. Therefore, processing in MVL cells is very likely more abstract than simple computations on the output of edge detectors. Copyright © 2018. Published by Elsevier B.V.

Visual loop-mediated isothermal amplification (LAMP) for the rapid diagnosis of Enterocytozoon hepatopenaei (EHP) infection.

PubMed

T, Sathish Kumar; A, Navaneeth Krishnan; J, Joseph Sahaya Rajan; M, Makesh; K P, Jithendran; S V, Alavandi; K K, Vijayan

2018-05-01

The emerging microsporidian parasite Enterocytozoon hepatopenaei (EHP), the causative agent of hepatopancreatic microsporidiosis, has been widely reported in shrimp-farming countries. EHP infection can be detected by light microscopy observation of spores (1.7 × 1 μm) in stained hepatopancreas (HP) tissue smears, HP tissue sections, and fecal samples. EHP can also be detected by polymerase chain reaction (PCR) targeting the small subunit (SSU) ribosomal RNA (rRNA) gene or the spore wall protein gene (SWP). In this study, a rapid, sensitive, specific, and closed tube visual loop-mediated isothermal amplification (LAMP) protocol combined with FTA cards was developed for the diagnosis of EHP. LAMP primers were designed based on the SSU rRNA gene of EHP. The target sequence of EHP was amplified at constant temperature of 65 °C for 45 min and amplified LAMP products were visually detected in a closed tube system by using SYBR™ green I dye. Detection limit of this LAMP protocol was ten copies. Field and clinical applicability of this assay was evaluated using 162 field samples including 106 HP tissue samples and 56 fecal samples collected from shrimp farms. Out of 162 samples, EHP could be detected in 62 samples (47 HP samples and 15 fecal samples). When compared with SWP-PCR as the gold standard, this EHP LAMP assay had 95.31% sensitivity, 98.98% specificity, and a kappa value of 0.948. This simple, closed tube, clinically evaluated visual LAMP assay has great potential for diagnosing EHP at the farm level, particularly under low-resource circumstances.

Information theoretic analysis of canny edge detection in visual communication

NASA Astrophysics Data System (ADS)

Jiang, Bo; Rahman, Zia-ur

2011-06-01

In general edge detection evaluation, the edge detectors are examined, analyzed, and compared either visually or with a metric for specific an application. This analysis is usually independent of the characteristics of the image-gathering, transmission and display processes that do impact the quality of the acquired image and thus, the resulting edge image. We propose a new information theoretic analysis of edge detection that unites the different components of the visual communication channel and assesses edge detection algorithms in an integrated manner based on Shannon's information theory. The edge detection algorithm here is considered to achieve high performance only if the information rate from the scene to the edge approaches the maximum possible. Thus, by setting initial conditions of the visual communication system as constant, different edge detection algorithms could be evaluated. This analysis is normally limited to linear shift-invariant filters so in order to examine the Canny edge operator in our proposed system, we need to estimate its "power spectral density" (PSD). Since the Canny operator is non-linear and shift variant, we perform the estimation for a set of different system environment conditions using simulations. In our paper we will first introduce the PSD of the Canny operator for a range of system parameters. Then, using the estimated PSD, we will assess the Canny operator using information theoretic analysis. The information-theoretic metric is also used to compare the performance of the Canny operator with other edge-detection operators. This also provides a simple tool for selecting appropriate edgedetection algorithms based on system parameters, and for adjusting their parameters to maximize information throughput.

Using false colors to protect visual privacy of sensitive content

NASA Astrophysics Data System (ADS)

Ćiftçi, Serdar; Korshunov, Pavel; Akyüz, Ahmet O.; Ebrahimi, Touradj

2015-03-01

Many privacy protection tools have been proposed for preserving privacy. Tools for protection of visual privacy available today lack either all or some of the important properties that are expected from such tools. Therefore, in this paper, we propose a simple yet effective method for privacy protection based on false color visualization, which maps color palette of an image into a different color palette, possibly after a compressive point transformation of the original pixel data, distorting the details of the original image. This method does not require any prior face detection or other sensitive regions detection and, hence, unlike typical privacy protection methods, it is less sensitive to inaccurate computer vision algorithms. It is also secure as the look-up tables can be encrypted, reversible as table look-ups can be inverted, flexible as it is independent of format or encoding, adjustable as the final result can be computed by interpolating the false color image with the original using different degrees of interpolation, less distracting as it does not create visually unpleasant artifacts, and selective as it preserves better semantic structure of the input. Four different color scales and four different compression functions, one which the proposed method relies, are evaluated via objective (three face recognition algorithms) and subjective (50 human subjects in an online-based study) assessments using faces from FERET public dataset. The evaluations demonstrate that DEF and RBS color scales lead to the strongest privacy protection, while compression functions add little to the strength of privacy protection. Statistical analysis also shows that recognition algorithms and human subjects perceive the proposed protection similarly

Perceptual Visual Grouping under Inattention: Electrophysiological Functional Imaging

ERIC Educational Resources Information Center

Razpurker-Apfeld, Irene; Pratt, Hillel

2008-01-01

Two types of perceptual visual grouping, differing in complexity of shape formation, were examined under inattention. Fourteen participants performed a similarity judgment task concerning two successive briefly presented central targets surrounded by task-irrelevant simple and complex grouping patterns. Event-related potentials (ERPs) were…

Caldera demonstration model

USGS Publications Warehouse

Venezky, Dina; Wessells, Stephen

2010-01-01

A caldera is a large, usually circular volcanic depression formed when magma is withdrawn or erupted from a shallow underground magma reservoir. It is often difficult to visualize how calderas form. This simple experiment using flour, a balloon, tubing, and a bicycle pump, provides a helpful visualization for caldera formation.

Prosodic Phonological Representations Early in Visual Word Recognition

ERIC Educational Resources Information Center

Ashby, Jane; Martin, Andrea E.

2008-01-01

Two experiments examined the nature of the phonological representations used during visual word recognition. We tested whether a minimality constraint (R. Frost, 1998) limits the complexity of early representations to a simple string of phonemes. Alternatively, readers might activate elaborated representations that include prosodic syllable…

The Deceptively Simple N170 Reflects Network Information Processing Mechanisms Involving Visual Feature Coding and Transfer Across Hemispheres

PubMed Central

Ince, Robin A. A.; Jaworska, Katarzyna; Gross, Joachim; Panzeri, Stefano; van Rijsbergen, Nicola J.; Rousselet, Guillaume A.; Schyns, Philippe G.

2016-01-01

A key to understanding visual cognition is to determine “where”, “when”, and “how” brain responses reflect the processing of the specific visual features that modulate categorization behavior—the “what”. The N170 is the earliest Event-Related Potential (ERP) that preferentially responds to faces. Here, we demonstrate that a paradigmatic shift is necessary to interpret the N170 as the product of an information processing network that dynamically codes and transfers face features across hemispheres, rather than as a local stimulus-driven event. Reverse-correlation methods coupled with information-theoretic analyses revealed that visibility of the eyes influences face detection behavior. The N170 initially reflects coding of the behaviorally relevant eye contralateral to the sensor, followed by a causal communication of the other eye from the other hemisphere. These findings demonstrate that the deceptively simple N170 ERP hides a complex network information processing mechanism involving initial coding and subsequent cross-hemispheric transfer of visual features. PMID:27550865

Colour and luminance contrasts predict the human detection of natural stimuli in complex visual environments.

PubMed

White, Thomas E; Rojas, Bibiana; Mappes, Johanna; Rautiala, Petri; Kemp, Darrell J

2017-09-01

Much of what we know about human colour perception has come from psychophysical studies conducted in tightly-controlled laboratory settings. An enduring challenge, however, lies in extrapolating this knowledge to the noisy conditions that characterize our actual visual experience. Here we combine statistical models of visual perception with empirical data to explore how chromatic (hue/saturation) and achromatic (luminant) information underpins the detection and classification of stimuli in a complex forest environment. The data best support a simple linear model of stimulus detection as an additive function of both luminance and saturation contrast. The strength of each predictor is modest yet consistent across gross variation in viewing conditions, which accords with expectation based upon general primate psychophysics. Our findings implicate simple visual cues in the guidance of perception amidst natural noise, and highlight the potential for informing human vision via a fusion between psychophysical modelling and real-world behaviour. © 2017 The Author(s).

Three-dimensional portable document format: a simple way to present 3-dimensional data in an electronic publication.

PubMed

Danz, Jan C; Katsaros, Christos

2011-08-01

Three-dimensional (3D) models of teeth and soft and hard tissues are tessellated surfaces used for diagnosis, treatment planning, appliance fabrication, outcome evaluation, and research. In scientific publications or communications with colleagues, these 3D data are often reduced to 2-dimensional pictures or need special software for visualization. The portable document format (PDF) offers a simple way to interactively display 3D surface data without additional software other than a recent version of Adobe Reader (Adobe, San Jose, Calif). The purposes of this article were to give an example of how 3D data and their analyses can be interactively displayed in 3 dimensions in electronic publications, and to show how they can be exported from any software for diagnostic reports and communications among colleagues. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Finding regions of interest in pathological images: an attentional model approach

NASA Astrophysics Data System (ADS)

Gómez, Francisco; Villalón, Julio; Gutierrez, Ricardo; Romero, Eduardo

2009-02-01

This paper introduces an automated method for finding diagnostic regions-of-interest (RoIs) in histopathological images. This method is based on the cognitive process of visual selective attention that arises during a pathologist's image examination. Specifically, it emulates the first examination phase, which consists in a coarse search for tissue structures at a "low zoom" to separate the image into relevant regions.1 The pathologist's cognitive performance depends on inherent image visual cues - bottom-up information - and on acquired clinical medicine knowledge - top-down mechanisms -. Our pathologist's visual attention model integrates the latter two components. The selected bottom-up information includes local low level features such as intensity, color, orientation and texture information. Top-down information is related to the anatomical and pathological structures known by the expert. A coarse approximation to these structures is achieved by an oversegmentation algorithm, inspired by psychological grouping theories. The algorithm parameters are learned from an expert pathologist's segmentation. Top-down and bottom-up integration is achieved by calculating a unique index for each of the low level characteristics inside the region. Relevancy is estimated as a simple average of these indexes. Finally, a binary decision rule defines whether or not a region is interesting. The method was evaluated on a set of 49 images using a perceptually-weighted evaluation criterion, finding a quality gain of 3dB when comparing to a classical bottom-up model of attention.

Short communication: Semiquantitative assessment of 99mTc-EDDA/HYNIC-TOC scintigraphy in differentiation of solitary pulmonary nodules--a complementary role to visual analysis.

PubMed

Płachcińska, Anna; Mikołajczak, Renata; Kozak, Józef; Rzeszutek, Katarzyna; Kuśmierek, Jacek

2006-02-01

The aim of this study was the assessment of a value of a semiquantitative analysis of scintigrams obtained with (99m)Tc-EDDA/HYNIC-TOC as a radiopharmaceutical (RPH) in differential diagnosis of solitary pulmonary nodules (SPNs), as a method complementary to visual evaluation of scintigrams. Scintigraphic images of 59 patients (33 males and 26 females between 34 and 78 years of age, mean value, 57) with SPN on chest radiographs (39 malignant and 20 benign) were retrospectively assessed semiquantitatively. Visual scintigram analysis was made earlier, prospectively. Nodule diameters ranged from 1 to 4 (mean 2.2) cm. A single photon emission computed tomography (SPECT) acquisition was performed at 2-4 hours after administration of 740 to 925 MBq of a RPH. Verification of scintigraphic results was based on a pathological examination of tumor samples (histopathology or cytology) and, in some cases, on bacteriological studies. As an additional criterion for tumor benignity, its stable size in a time interval not shorter than 3 years was accepted. A simple, semiquantitative method for assessment of radiopharmaceutical uptake in SPNs was used, based on "count sample" taken from tumor center (T) in relation to radiopharmaceutical concentration in the background (B) measured in the contralateral lung. A criterion for optimal differentiation between malignant and benign nodules (T/B ratio threshold value) was introduced, based on a receiver operating characteristic (ROC) curve. Additionally, a value of T/B ratio was searched for, excluding tumor benignity with high probability. Visual analysis of scintigrams revealed enhanced uptake of RPH at 36 of 39 (92%) sites, corresponding to locations of malignant nodules (including 34 of 35-97% cases of lung cancer). In 13 of 20 (65%) benign nodules, true negative results were obtained. Accuracy of the method equalled 83%. Optimal differentiation between malignant and benign nodules was found for a value of a T/B ratio amounting to 2. The semiquantitative method gave true positive results in 35 of 39 (90%) malignant nodules (as in visual method in 34 of 35-97% cases of lung cancer). True negative results were obtained in 17 of 20 (85%) benign cases. Accuracy of the method reached 88%. A T/B ratio exceeding 4 excluded tumor benignity with high probability. A simple method, of quantitatively assessing 99mTc-EDDA/HYNICTOC uptake in solitary pulmonary nodules by means of a T/B ratio can play a role that is complementary to the visual evaluation of scintigrams. It improves low specificity of the method in the detection of malignant nodules, without significant reduction of its sensitivity and provides a T/B ratio excluding tumor benignity with high probability.

An Object-oriented Taxonomy of Medical Data Presentations

PubMed Central

Starren, Justin; Johnson, Stephen B.

2000-01-01

A variety of methods have been proposed for presenting medical data visually on computers. Discussion of and comparison among these methods have been hindered by a lack of consistent terminology. A taxonomy of medical data presentations based on object-oriented user interface principles is presented. Presentations are divided into five major classes—list, table, graph, icon, and generated text. These are subdivided into eight subclasses with simple inheritance and four subclasses with multiple inheritance. The various subclasses are reviewed and examples are provided. Issues critical to the development and evaluation of presentations are also discussed. PMID:10641959

An ideal observer analysis of visual working memory.

PubMed

Sims, Chris R; Jacobs, Robert A; Knill, David C

2012-10-01

Limits in visual working memory (VWM) strongly constrain human performance across many tasks. However, the nature of these limits is not well understood. In this article we develop an ideal observer analysis of human VWM by deriving the expected behavior of an optimally performing but limited-capacity memory system. This analysis is framed around rate-distortion theory, a branch of information theory that provides optimal bounds on the accuracy of information transmission subject to a fixed information capacity. The result of the ideal observer analysis is a theoretical framework that provides a task-independent and quantitative definition of visual memory capacity and yields novel predictions regarding human performance. These predictions are subsequently evaluated and confirmed in 2 empirical studies. Further, the framework is general enough to allow the specification and testing of alternative models of visual memory (e.g., how capacity is distributed across multiple items). We demonstrate that a simple model developed on the basis of the ideal observer analysis-one that allows variability in the number of stored memory representations but does not assume the presence of a fixed item limit-provides an excellent account of the empirical data and further offers a principled reinterpretation of existing models of VWM. PsycINFO Database Record (c) 2012 APA, all rights reserved.

Visual Detection of West Nile Virus Using Reverse Transcription Loop-Mediated Isothermal Amplification Combined with a Vertical Flow Visualization Strip.

PubMed

Cao, Zengguo; Wang, Hualei; Wang, Lina; Li, Ling; Jin, Hongli; Xu, Changping; Feng, Na; Wang, Jianzhong; Li, Qian; Zhao, Yongkun; Wang, Tiecheng; Gao, Yuwei; Lu, Yiyu; Yang, Songtao; Xia, Xianzhu

2016-01-01

West Nile virus (WNV) causes a severe zoonosis, which can lead to a large number of casualties and considerable economic losses. A rapid and accurate identification method for WNV for use in field laboratories is urgently needed. Here, a method utilizing reverse transcription loop-mediated isothermal amplification combined with a vertical flow visualization strip (RT-LAMP-VF) was developed to detect the envelope (E) gene of WNV. The RT-LAMP-VF assay could detect 10(2) copies/μl of an WNV RNA standard using a 40 min amplification reaction followed by a 2 min incubation of the amplification product on the visualization strip, and no cross-reaction with other closely related members of the Flavivirus genus was observed. The assay was further evaluated using cells and mouse brain tissues infected with a recombinant rabies virus expressing the E protein of WNV. The assay produced sensitivities of 10(1.5) TCID50/ml and 10(1.33) TCID50/ml for detection of the recombinant virus in the cells and brain tissues, respectively. Overall, the RT-LAMP-VF assay developed in this study is rapid, simple and effective, and it is therefore suitable for clinical application in the field.

Visual cortical areas of the mouse: comparison of parcellation and network structure with primates

PubMed Central

Laramée, Marie-Eve; Boire, Denis

2015-01-01

Brains have evolved to optimize sensory processing. In primates, complex cognitive tasks must be executed and evolution led to the development of large brains with many cortical areas. Rodents do not accomplish cognitive tasks of the same level of complexity as primates and remain with small brains both in relative and absolute terms. But is a small brain necessarily a simple brain? In this review, several aspects of the visual cortical networks have been compared between rodents and primates. The visual system has been used as a model to evaluate the level of complexity of the cortical circuits at the anatomical and functional levels. The evolutionary constraints are first presented in order to appreciate the rules for the development of the brain and its underlying circuits. The organization of sensory pathways, with their parallel and cross-modal circuits, is also examined. Other features of brain networks, often considered as imposing constraints on the development of underlying circuitry, are also discussed and their effect on the complexity of the mouse and primate brain are inspected. In this review, we discuss the common features of cortical circuits in mice and primates and see how these can be useful in understanding visual processing in these animals. PMID:25620914

Visual cortical areas of the mouse: comparison of parcellation and network structure with primates.

PubMed

Laramée, Marie-Eve; Boire, Denis

2014-01-01

Brains have evolved to optimize sensory processing. In primates, complex cognitive tasks must be executed and evolution led to the development of large brains with many cortical areas. Rodents do not accomplish cognitive tasks of the same level of complexity as primates and remain with small brains both in relative and absolute terms. But is a small brain necessarily a simple brain? In this review, several aspects of the visual cortical networks have been compared between rodents and primates. The visual system has been used as a model to evaluate the level of complexity of the cortical circuits at the anatomical and functional levels. The evolutionary constraints are first presented in order to appreciate the rules for the development of the brain and its underlying circuits. The organization of sensory pathways, with their parallel and cross-modal circuits, is also examined. Other features of brain networks, often considered as imposing constraints on the development of underlying circuitry, are also discussed and their effect on the complexity of the mouse and primate brain are inspected. In this review, we discuss the common features of cortical circuits in mice and primates and see how these can be useful in understanding visual processing in these animals.

The Diffusion Simulator - Teaching Geomorphic and Geologic Problems Visually.

ERIC Educational Resources Information Center

Gilbert, R.

1979-01-01

Describes a simple hydraulic simulator based on more complex models long used by engineers to develop approximate solutions. It allows students to visualize non-steady transfer, to apply a model to solve a problem, and to compare experimentally simulated information with calculated values. (Author/MA)

Photoelectron Imaging as a Quantum Chemistry Visualization Tool

ERIC Educational Resources Information Center

Grumbling, Emily R.; Pichugin, Kostyantyn; Mabbs, Richard; Sanov, Andrei

2011-01-01

An overview and simple example of photoelectron imaging is presented, highlighting its efficacy as a pedagogical tool for visualizing quantum phenomena. Specifically, photoelectron imaging of H[superscript -] (the simplest negative ion) is used to demonstrate several quantum mechanical principles. This example could be incorporated into an…

Prototype crawling robotics system for remote visual inspection of high-mast light poles.

DOT National Transportation Integrated Search

1997-01-01

This report presents the results of a project to develop a crawling robotics system for the remote visual inspection of high-mast light poles in Virginia. The first priority of this study was to develop a simple robotics application that would reduce...

The impact of interference on short-term memory for visual orientation.

PubMed

Rademaker, Rosanne L; Bloem, Ilona M; De Weerd, Peter; Sack, Alexander T

2015-12-01

Visual short-term memory serves as an efficient buffer for maintaining no longer directly accessible information. How robust are visual memories against interference? Memory for simple visual features has proven vulnerable to distractors containing conflicting information along the relevant stimulus dimension, leading to the idea that interacting feature-specific channels at an early stage of visual processing support memory for simple visual features. Here we showed that memory for a single randomly orientated grating was susceptible to interference from a to-be-ignored distractor grating presented midway through a 3-s delay period. Memory for the initially presented orientation became noisier when it differed from the distractor orientation, and response distributions were shifted toward the distractor orientation (by ∼3°). Interestingly, when the distractor was rendered task-relevant by making it a second memory target, memory for both retained orientations showed reduced reliability as a function of increased orientation differences between them. However, the degree to which responses to the first grating shifted toward the orientation of the task-relevant second grating was much reduced. Finally, using a dichoptic display, we demonstrated that these systematic biases caused by a consciously perceived distractor disappeared once the distractor was presented outside of participants' awareness. Together, our results show that visual short-term memory for orientation can be systematically biased by interfering information that is consciously perceived. (c) 2015 APA, all rights reserved).

Computational models of cortical visual processing.

PubMed Central

Heeger, D J; Simoncelli, E P; Movshon, J A

1996-01-01

The visual responses of neurons in the cerebral cortex were first adequately characterized in the 1960s by D. H. Hubel and T. N. Wiesel [(1962) J. Physiol. (London) 160, 106-154; (1968) J. Physiol. (London) 195, 215-243] using qualitative analyses based on simple geometric visual targets. Over the past 30 years, it has become common to consider the properties of these neurons by attempting to make formal descriptions of these transformations they execute on the visual image. Most such models have their roots in linear-systems approaches pioneered in the retina by C. Enroth-Cugell and J. R. Robson [(1966) J. Physiol. (London) 187, 517-552], but it is clear that purely linear models of cortical neurons are inadequate. We present two related models: one designed to account for the responses of simple cells in primary visual cortex (V1) and one designed to account for the responses of pattern direction selective cells in MT (or V5), an extrastriate visual area thought to be involved in the analysis of visual motion. These models share a common structure that operates in the same way on different kinds of input, and instantiate the widely held view that computational strategies are similar throughout the cerebral cortex. Implementations of these models for Macintosh microcomputers are available and can be used to explore the models' properties. PMID:8570605

Evaluating the operations underlying multisensory integration in the cat superior colliculus.

PubMed

Stanford, Terrence R; Quessy, Stephan; Stein, Barry E

2005-07-13

It is well established that superior colliculus (SC) multisensory neurons integrate cues from different senses; however, the mechanisms responsible for producing multisensory responses are poorly understood. Previous studies have shown that spatially congruent cues from different modalities (e.g., auditory and visual) yield enhanced responses and that the greatest relative enhancements occur for combinations of the least effective modality-specific stimuli. Although these phenomena are well documented, little is known about the mechanisms that underlie them, because no study has systematically examined the operation that multisensory neurons perform on their modality-specific inputs. The goal of this study was to evaluate the computations that multisensory neurons perform in combining the influences of stimuli from two modalities. The extracellular activities of single neurons in the SC of the cat were recorded in response to visual, auditory, and bimodal visual-auditory stimulation. Each neuron was tested across a range of stimulus intensities and multisensory responses evaluated against the null hypothesis of simple summation of unisensory influences. We found that the multisensory response could be superadditive, additive, or subadditive but that the computation was strongly dictated by the efficacies of the modality-specific stimulus components. Superadditivity was most common within a restricted range of near-threshold stimulus efficacies, whereas for the majority of stimuli, response magnitudes were consistent with the linear summation of modality-specific influences. In addition to providing a constraint for developing models of multisensory integration, the relationship between response mode and stimulus efficacy emphasizes the importance of considering stimulus parameters when inducing or interpreting multisensory phenomena.

Using complex auditory-visual samples to produce emergent relations in children with autism.

PubMed

Groskreutz, Nicole C; Karsina, Allen; Miguel, Caio F; Groskreutz, Mark P

2010-03-01

Six participants with autism learned conditional relations between complex auditory-visual sample stimuli (dictated words and pictures) and simple visual comparisons (printed words) using matching-to-sample training procedures. Pre- and posttests examined potential stimulus control by each element of the complex sample when presented individually and emergence of additional conditional relations and oral labeling. Tests revealed class-consistent performance for all participants following training.

Long-term Recurrent Convolutional Networks for Visual Recognition and Description

DTIC Science & Technology

2014-11-17

deep???, are effective for tasks involving sequences, visual and otherwise. We develop a novel recurrent convolutional architecture suitable for large...models which are also recurrent, or “temporally deep”, are effective for tasks involving sequences, visual and otherwise. We develop a novel recurrent...limitation of simple RNN models which strictly integrate state information over time is known as the “vanishing gradient” effect : the ability to

The wisdom of crowds for visual search

PubMed Central

Juni, Mordechai Z.; Eckstein, Miguel P.

2017-01-01

Decision-making accuracy typically increases through collective integration of people’s judgments into group decisions, a phenomenon known as the wisdom of crowds. For simple perceptual laboratory tasks, classic signal detection theory specifies the upper limit for collective integration benefits obtained by weighted averaging of people’s confidences, and simple majority voting can often approximate that limit. Life-critical perceptual decisions often involve searching large image data (e.g., medical, security, and aerial imagery), but the expected benefits and merits of using different pooling algorithms are unknown for such tasks. Here, we show that expected pooling benefits are significantly greater for visual search than for single-location perceptual tasks and the prediction given by classic signal detection theory. In addition, we show that simple majority voting obtains inferior accuracy benefits for visual search relative to averaging and weighted averaging of observers’ confidences. Analysis of gaze behavior across observers suggests that the greater collective integration benefits for visual search arise from an interaction between the foveated properties of the human visual system (high foveal acuity and low peripheral acuity) and observers’ nonexhaustive search patterns, and can be predicted by an extended signal detection theory framework with trial to trial sampling from a varying mixture of high and low target detectabilities across observers (SDT-MIX). These findings advance our theoretical understanding of how to predict and enhance the wisdom of crowds for real world search tasks and could apply more generally to any decision-making task for which the minority of group members with high expertise varies from decision to decision. PMID:28490500

Cell structure and function in the visual cortex of the cat

PubMed Central

Kelly, J. P.; Van Essen, D. C.

1974-01-01

1. The organization of the visual cortex was studied with a technique that allows one to determine the physiology and morphology of individual cells. Micro-electrodes filled with the fluorescent dye Procion yellow were used to record intracellularly from cells in area 17 of the cat. The visual receptive field of each neurone was classified as simple, complex, or hypercomplex, and the cell was then stained by the iontophoretic injection of dye. 2. Fifty neurones were successfully examined in this way, and their structural features were compared to the varieties of cell types seen in Golgi preparations of area 17. The majority of simple units were stellate cells, whereas the majority of complex and hypercomplex units were pyramidal cells. Several neurones belonged to less common morphological types, such as double bouquet cells. Simple cells were concentrated in layer IV, hypercomplex cells in layer II + III, and complex cells in layers II + III, V and VI. 3. Electrically inexcitable cells that had high resting potentials but no impulse activity were stained and identified as glial cells. Glial cells responded to visual stimuli with slow graded depolarizations, and many of them showed a preference for a stimulus orientation similar to the optimal orientation for adjacent neurones. 4. The results show that there is a clear, but not absolute correlation between the major structural and functional classes of cells in the visual cortex. This approach, linking the physiological properties of a single cell to a given morphological type, will help in furthering our understanding of the cerebral cortex. ImagesPlate 4Plate 1Plate 2Plate 3 PMID:4136579

Gestalt Perceptual Organization of Visual Stimuli Captures Attention Automatically: Electrophysiological Evidence

PubMed Central

Marini, Francesco; Marzi, Carlo A.

2016-01-01

The visual system leverages organizational regularities of perceptual elements to create meaningful representations of the world. One clear example of such function, which has been formalized in the Gestalt psychology principles, is the perceptual grouping of simple visual elements (e.g., lines and arcs) into unitary objects (e.g., forms and shapes). The present study sought to characterize automatic attentional capture and related cognitive processing of Gestalt-like visual stimuli at the psychophysiological level by using event-related potentials (ERPs). We measured ERPs during a simple visual reaction time task with bilateral presentations of physically matched elements with or without a Gestalt organization. Results showed that Gestalt (vs. non-Gestalt) stimuli are characterized by a larger N2pc together with enhanced ERP amplitudes of non-lateralized components (N1, N2, P3) starting around 150 ms post-stimulus onset. Thus, we conclude that Gestalt stimuli capture attention automatically and entail characteristic psychophysiological signatures at both early and late processing stages. Highlights We studied the neural signatures of the automatic processes of visual attention elicited by Gestalt stimuli. We found that a reliable early correlate of attentional capture turned out to be the N2pc component. Perceptual and cognitive processing of Gestalt stimuli is associated with larger N1, N2, and P3 PMID:27630555

Design of a noninvasive face mask for ocular occlusion in rats and assessment in a visual discrimination paradigm.

PubMed

Hager, Audrey M; Dringenberg, Hans C

2012-12-01

The rat visual system is structured such that the large (>90 %) majority of retinal ganglion axons reach the contralateral lateral geniculate nucleus (LGN) and visual cortex (V1). This anatomical design allows for the relatively selective activation of one cerebral hemisphere under monocular viewing conditions. Here, we describe the design of a harness and face mask allowing simple and noninvasive monocular occlusion in rats. The harness is constructed from synthetic fiber (shoelace-type material) and fits around the girth region and neck, allowing for easy adjustments to fit rats of various weights. The face mask consists of soft rubber material that is attached to the harness by Velcro strips. Eyeholes in the mask can be covered by additional Velcro patches to occlude either one or both eyes. Rats readily adapt to wearing the device, allowing behavioral testing under different types of viewing conditions. We show that rats successfully acquire a water-maze-based visual discrimination task under monocular viewing conditions. Following task acquisition, interocular transfer was assessed. Performance with the previously occluded, "untrained" eye was impaired, suggesting that training effects were partially confined to one cerebral hemisphere. The method described herein provides a simple and noninvasive means to restrict visual input for studies of visual processing and learning in various rodent species.

Functional vision and cognition in infants with congenital disorders of the peripheral visual system.

PubMed

Dale, Naomi; Sakkalou, Elena; O'Reilly, Michelle; Springall, Clare; De Haan, Michelle; Salt, Alison

2017-07-01

To investigate how vision relates to early development by studying vision and cognition in a national cohort of 1-year-old infants with congenital disorders of the peripheral visual system and visual impairment. This was a cross-sectional observational investigation of a nationally recruited cohort of infants with 'simple' and 'complex' congenital disorders of the peripheral visual system. Entry age was 8 to 16 months. Vision level (Near Detection Scale) and non-verbal cognition (sensorimotor understanding, Reynell Zinkin Scales) were assessed. Parents completed demographic questionnaires. Of 90 infants (49 males, 41 females; mean 13mo, standard deviation [SD] 2.5mo; range 7-17mo); 25 (28%) had profound visual impairment (light perception at best) and 65 (72%) had severe visual impairment (basic 'form' vision). The Near Detection Scale correlated significantly with sensorimotor understanding developmental quotients in the 'total', 'simple', and 'complex' groups (all p<0.001). Age and vision accounted for 48% of sensorimotor understanding variance. Infants with profound visual impairment, especially in the 'complex' group with congenital disorders of the peripheral visual system with known brain involvement, showed the greatest cognitive delay. Lack of vision is associated with delayed early-object manipulative abilities and concepts; 'form' vision appeared to support early developmental advance. This paper provides baseline characteristics for cross-sectional and longitudinal follow-up investigations in progress. A methodological strength of the study was the representativeness of the cohort according to national epidemiological and population census data. © 2017 Mac Keith Press.

Comparison of human driver dynamics in simulators with complex and simple visual displays and in an automobile on the road

NASA Technical Reports Server (NTRS)

Mcruer, D. T.; Klein, R. H.

1975-01-01

As part of a comprehensive program exploring driver/vehicle system response in lateral steering tasks, driver/vehicle system describing functions and other dynamic data have been gathered in several milieu. These include a simple fixed base simulator with an elementary roadway delineation only display; a fixed base statically operating automobile with a terrain model based, wide angle projection system display; and a full scale moving base automobile operating on the road. Dynamic data with the two fixed base simulators compared favorably, implying that the impoverished visual scene, lack of engine noise, and simplified steering wheel feel characteristics in the simple simulator did not induce significant driver dynamic behavior variations. The fixed base vs. moving base comparisons showed substantially greater crossover frequencies and phase margins on the road course.

Simple spectroscope used with solid state image amplifier over wide spectral range

NASA Technical Reports Server (NTRS)

Brown, R. L., Sr.

1971-01-01

Prism plus image amplifier panel provides visual image of many infrared spectral lines from carbon arc impregnated with metal compound. Different metal compounds generate various desired spectra. Panel also aligns and focuses simple spectroscopes for detecting spectral lines inside and outside visible region.

Optimizing Opto-mechanical Performance Using Simple Tools and Techniques

NASA Astrophysics Data System (ADS)

Krajci, Tom

2009-05-01

You just purchased a modest setup for your observatory - perhaps a mass produced Schmidt-Cassegrain on a German equatorial mount. However, optically and mechanically it's not performing as well as you would like. What can you do? Some simple assessments and repairs may make all the difference. Assessments can be as easy as visual inspection of various mount components, such as the tripod, where gaps between components reduce stiffness or allow unexpected shifts when loads change. Some assessments are only slightly more involved. Main mirror flop can be evaluated by aligning the main telescope and finder on a bright star and then slewing to various parts of the sky. Pointing differences between the two will be readily apparent if this problem exists. Most mid-level mounts use worm drives, but often excessive spacing between worm and worm gear produces large, and unnecessary amounts of backlash. Visual inspection of your dovetail mounting system may leave doubts in your mind as to adequate stiffness. Imaging through the entire night may show you that your aluminum tube telescope causes excessive focus shift as temperature drops. Over time, your Schmidt-Cassegrain corrector plate may no longer be securely held by its retaining ring, and the same may apply to the secondary mirror cell. Repairs for these problems are often not difficult if you're mechanically inclined. Gaps in mount components can be eliminated with shims. Combating mirror flop may be the most difficult task. This can involve re-gluing the main mirror and bolting the main mirror cell in a fixed position. Corrector plate and secondary mirror cells can be improved with setscrews and shims - implementing sound kinematic principles. Worm gear spacing can often be adjusted with simple tools. This brief paper can't possibly cover all problems and solutions, but it can give you the proper mindset to looking at your system with a critical eye and implementing simple, inexpensive fixes. You may be pleasantly surprised by the improvements.

Visualizing Chemistry with Infrared Imaging

ERIC Educational Resources Information Center

Xie, Charles

2011-01-01

Almost all chemical processes release or absorb heat. The heat flow in a chemical system reflects the process it is undergoing. By showing the temperature distribution dynamically, infrared (IR) imaging provides a salient visualization of the process. This paper presents a set of simple experiments based on IR imaging to demonstrate its enormous…

Use of a Computer Simulation To Develop Mental Simulations for Understanding Relative Motion Concepts.

ERIC Educational Resources Information Center

Monaghan, James M.; Clement, John

1999-01-01

Presents evidence for students' qualitative and quantitative difficulties with apparently simple one-dimensional relative-motion problems, students' spontaneous visualization of relative-motion problems, the visualizations facilitating solution of these problems, and students' memories of the online computer simulation used as a framework for…

"Delta Plots"--A New Way to Visualize Electronic Excitation.

ERIC Educational Resources Information Center

Morrison, Harry; And Others

1985-01-01

Presents procedures for obtaining and examples of delta plots (a way of illustrating electron density changes associated with electronic excitation). These plots are pedagogically useful for visualizing simple and complex transitions and provide a way of "seeing" the origin of highest occupied molecular orbital (HOMO)-dictated carbonyl…

Structured Natural-Language Descriptions for Semantic Content Retrieval of Visual Materials.

ERIC Educational Resources Information Center

Tam, A. M.; Leung, C. H. C.

2001-01-01

Proposes a structure for natural language descriptions of the semantic content of visual materials that requires descriptions to be (modified) keywords, phrases, or simple sentences, with components that are grammatical relations common to many languages. This structure makes it easy to implement a collection's descriptions as a relational…

Spatial Probability Cuing and Right Hemisphere Damage

ERIC Educational Resources Information Center

Shaqiri, Albulena; Anderson, Britt

2012-01-01

In this experiment we studied statistical learning, inter-trial priming, and visual attention. We assessed healthy controls and right brain damaged (RBD) patients with and without neglect, on a simple visual discrimination task designed to measure priming effects and probability learning. All participants showed a preserved priming effect for item…

Investigating Complexity Using Excel and Visual Basic.

ERIC Educational Resources Information Center

Zetie, K. P.

2001-01-01

Shows how some of the simple ideas in complexity can be investigated using a spreadsheet and a macro written in Visual Basic. Shows how the sandpile model of Bak, Chao, and Wiesenfeld can be simulated and animated. The model produces results that cannot easily be predicted from its properties. (Author/MM)

The Structure of Visuospatial Memory in Adulthood

ERIC Educational Resources Information Center

Mammarella, Irene C.; Borella, Erika; Pastore, Massimiliano; Pazzaglia, Francesca

2013-01-01

The present study aimed to investigate the structure of visuospatial memory in adulthood. Adults 40-89 years of age (n = 160) performed simple storage and complex visuospatial span tasks. Simple storage tasks were distinguished into three presentation formats: (i) visual, which involved maintaining shapes and textures; (ii) spatial-sequential,…

The Box-and-Dot Method: A Simple Strategy for Counting Significant Figures

NASA Astrophysics Data System (ADS)

Stephenson, W. Kirk

2009-08-01

A visual method for counting significant digits is presented. This easy-to-learn (and easy-to-teach) method, designated the box-and-dot method, uses the device of "boxing" significant figures based on two simple rules, then counting the number of digits in the boxes.

A Practical Workshop for Generating Simple DNA Fingerprints of Plants

ERIC Educational Resources Information Center

Rouziere, A.-S.; Redman, J. E.

2011-01-01

Gel electrophoresis DNA fingerprints offer a graphical and visually appealing illumination of the similarities and differences between DNA sequences of different species and individuals. A polymerase chain reaction (PCR) and restriction digest protocol was designed to give high-school students the opportunity to generate simple fingerprints of…

Novel technique for the preparation of corneal grafts for descemet membrane endothelial keratoplasty.

PubMed

Muraine, Marc; Gueudry, Julie; He, Zhiguo; Piselli, Simone; Lefevre, Sabine; Toubeau, David

2013-11-01

To report a simple novel technique to facilitate preparation of Descemet membrane grafts for Descemet membrane endothelial keratoplasty (DMEK). Laboratory investigation and retrospective, single-center, consecutive case series. Preparation of the endothelial graft is performed on an artificial anterior chamber, endothelial side up. After an incomplete circular superficial trephination, we describe a simple technique using a 27 gauge cannula to detach the Descemet membrane (DM). Endothelial cell density (ECD) was measured before dissection on 12 human corneas for research and 3 days after storage in organ culture. Histologic and electron microscopy analysis were performed. A DMEK was performed in 50 patients with Fuchs dystrophy. Visual acuity and ECD were evaluated 2 and 6 months after surgery. ECD was 2765 ± 256 cells/mm(2) on corneas for research before dissection and 2651 ± 305 cells/mm(2) after 3 days in organ culture (P < .01). Histologic and electronic sections confirm that the cleavage was between DM and posterior stroma. Clinically, preparation of 2 corneas from a single donor was unsuccessful; 48 corneas were clear at 2 months and 47 at 6 months. At 2 months 77% of the patients had recovered a visual acuity of at least 20/30. At 6 months, 91.5% of the patients had a visual acuity of at least 20/30. ECD was 2656 ± 28 cells/mm(2) (range: 2450-3100 cells/mm(2)) preoperatively, 1797 ± 41 cells/mm(2) (range: 1100-2700 cells/mm(2)) at 2 months, and 1658 ± 43 cells/mm(2) (range: 900-2600 cells/mm(2)) at 6 months. We report here a reliable and efficient technique for the preparation of pure Descemet membrane grafts. Copyright © 2013 Elsevier Inc. All rights reserved.

Lateral-flow colloidal gold-based immunoassay for the rapid detection of deoxynivalenol with two indicator ranges.

PubMed

Kolosova, Anna Yu; Sibanda, Liberty; Dumoulin, Frédéric; Lewis, Janet; Duveiller, Etienne; Van Peteghem, Carlos; De Saeger, Sarah

2008-06-02

A lateral-flow immunoassay using a colloidal gold-labelled monoclonal antibody was developed for the rapid detection of deoxynivalenol (DON). Different parameters, such as the amount of immunoreagents, type of the materials, composition of the blocking solution and of the detector reagent mixture, were investigated to provide the optimum assay performance. The experimental results demonstrated that such a visual test had an indicator range rather than a cut-off value. Thus, tests for DON determination with two different indicator ranges of 250-500 and 1000-2000 microg kg(-1) were designed. The method allowed detection of DON at low and high concentration levels, which could be useful for research and practical purposes. The assay applied to spiked wheat and pig feed samples demonstrated accurate and reproducible results. The applicability of the developed lateral-flow test was also confirmed under real field conditions. The test strips prepared in Belgium were sent to Mexico, where they were used for the screening of DON contamination in different bread wheat entries from Fusarium Head Blight inoculated plots. The results were compared with those obtained by ELISA and LC-MS/MS. A poor correlation between ELISA and LC-MS/MS was observed. Visual results of the dipstick tests were in a good agreement with the results of the LC-MS/MS method. Coupled with a simple and fast sample preparation, this qualitative one-step test based on the visual evaluation of results did not require any equipment. Results could be obtained within 10 min. The described assay format can be used as a simple, rapid, cost-effective and robust on-site screening tool for mycotoxin contamination in different agricultural commodities.

VRML metabolic network visualizer.

PubMed

Rojdestvenski, Igor

2003-03-01

A successful date collection visualization should satisfy a set of many requirements: unification of diverse data formats, support for serendipity research, support of hierarchical structures, algorithmizability, vast information density, Internet-readiness, and other. Recently, virtual reality has made significant progress in engineering, architectural design, entertainment and communication. We experiment with the possibility of using the immersive abstract three-dimensional visualizations of the metabolic networks. We present the trial Metabolic Network Visualizer software, which produces graphical representation of a metabolic network as a VRML world from a formal description written in a simple SGML-type scripting language.

A Visual Analogue Scale and a Likert Scale are Simple and Responsive Tools for Assessing Dysphagia in Eosinophilic Esophagitis

PubMed Central

Reed, Craig C.; Wolf, W. Asher; Cotton, Cary C.; Dellon, Evan S.

2017-01-01

Background While symptom scores have been developed to evaluate dysphagia in eosinophilic oesophagitis (EoE), their complexity may limit clinical use. Aim We aimed to evaluate a visual analogue scale (VAS) and a 10 point Likert scale (LS) for assessment of dysphagia severity before and after EoE treatment. Methods We conducted a prospective cohort study enrolling consecutive adults undergoing outpatient endoscopy. Incident cases of EoE were diagnosed per consensus guidelines. At diagnosis and after 8 weeks of treatment, symptoms were measured using the VAS, LS, and the Mayo Dysphagia Questionnaire (MDQ). The percentage change in scores before and after treatment were compared overall, in treatment responders (<15 eos/hpf) and non-responders, and in patients without baseline dilation. Results In 51 EoE cases, the median VAS decreased from 3.6 at baseline to 1.4 post-treatment (71% decrease), the LS decreased from 6 to 2 (67%), and the MDQ decreased from 20 to 10 (49%). The VAS correlated with both the LS (R=0.77; p<0.0001) and MDQ (R=0.46, p=0.001). After stratification by histologic response, the LS decreased 70% in responders vs. 13% in non-responders (p=0.02). In patients who did not receive baseline dilation, both the VAS and LS decreased significantly more in the histologic responders. Conclusions Both the VAS and LS were responsive to successful histologic treatment. Because the VAS and LS are simple to administer and are responsive to treatment, they can provide an efficient and objective method for assessing dysphagia severity in EoE in clinical practice. PMID:28370355

A visual analogue scale and a Likert scale are simple and responsive tools for assessing dysphagia in eosinophilic oesophagitis.

PubMed

Reed, C C; Wolf, W A; Cotton, C C; Dellon, E S

2017-06-01

While symptom scores have been developed to evaluate dysphagia in eosinophilic oesophagitis (EoE), their complexity may limit clinical use. To evaluate a visual analogue scale (VAS) and a 10-point Likert scale (LS) for assessment of dysphagia severity before and after EoE treatment. We conducted a prospective cohort study enrolling consecutive adults undergoing out-patient endoscopy. Incident cases of EoE were diagnosed per consensus guidelines. At diagnosis and after 8 weeks of treatment, symptoms were measured using the VAS, LS and the Mayo Dysphagia Questionnaire (MDQ). The percentage change in scores before and after treatment were compared overall, in treatment responders (<15 eos/hpf) and non-responders, and in patients without baseline dilation. In 51 EoE cases, the median VAS decreased from 3.6 at baseline to 1.4 post-treatment (71% decrease), the LS decreased from 6 to 2 (67%) and the MDQ decreased from 20 to 10 (49%). The VAS correlated with both the LS (R = 0.77; P < 0.0001) and MDQ (R = 0.46, P = 0.001). After stratification by histological response, the LS decreased 70% in responders vs. 13% in non-responders (P = 0.02). In patients who did not receive baseline dilation, both the VAS and LS decreased significantly more in the histological responders. Both the VAS and LS were responsive to successful treatment as measured by histologic improvement. Because the VAS and LS are simple to administer and are responsive to treatment, they can provide an efficient and objective method for assessing dysphagia severity in EoE in clinical practice. © 2017 John Wiley & Sons Ltd.

Acute effect of scapular proprioceptive neuromuscular facilitation (PNF) techniques and classic exercises in adhesive capsulitis: a randomized controlled trial

PubMed Central

Balcı, Nilay Comuk; Yuruk, Zeliha Ozlem; Zeybek, Aslican; Gulsen, Mustafa; Tekindal, Mustafa Agah

2016-01-01

[Purpose] The aim of our study was to compare the initial effects of scapular proprioceptive neuromuscular facilitation techniques and classic exercise interventions with physiotherapy modalities on pain, scapular dyskinesis, range of motion, and function in adhesive capsulitis. [Subjects and Methods] Fifty-three subjects were allocated to 3 groups: scapular proprioceptive neuromuscular facilitation exercies and physiotherapy modalities, classic exercise and physiotherapy modalities, and only physiotherapy modalities. The intervention was applied in a single session. The Visual Analog Scale, Lateral Scapular Slide Test, range of motion and Simple Shoulder Test were evaluated before and just after the one-hour intervention in the same session (all in one session). [Results] All of the groups showed significant differences in shoulder flexion and abduction range of motion and Simple Shoulder Test scores. There were statistically significant differences in Visual Analog Scale scores in the proprioceptive neuromuscular facilitation and control groups, and no treatment method had significant effect on the Lateral Scapular Slide Test results. There were no statistically significant differences between the groups before and after the intervention. [Conclusion] Proprioceptive neuromuscular facilitation, classic exercise, and physiotherapy modalities had immediate effects on adhesive capsulitis in our study. However, there was no additional benefit of exercises in one session over physiotherapy modalities. Also, an effective treatment regimen for shoulder rehabilitation of adhesive capsulitis patients should include scapular exercises. PMID:27190456

Cultural influences on neural substrates of attentional control.

PubMed

Hedden, Trey; Ketay, Sarah; Aron, Arthur; Markus, Hazel Rose; Gabrieli, John D E

2008-01-01

Behavioral research has shown that people from Western cultural contexts perform better on tasks emphasizing independent (absolute) dimensions than on tasks emphasizing interdependent (relative) dimensions, whereas the reverse is true for people from East Asian contexts. We assessed functional magnetic resonance imaging responses during performance of simple visuospatial tasks in which participants made absolute judgments (ignoring visual context) or relative judgments (taking visual context into account). In each group, activation in frontal and parietal brain regions known to be associated with attentional control was greater during culturally nonpreferred judgments than during culturally preferred judgments. Also, within each group, activation differences in these regions correlated strongly with scores on questionnaires measuring individual differences in culture-typical identity. Thus, the cultural background of an individual and the degree to which the individual endorses cultural values moderate activation in brain networks engaged during even simple visual and attentional tasks.

Crowding with detection and coarse discrimination of simple visual features.

PubMed

Põder, Endel

2008-04-24

Some recent studies have suggested that there are actually no crowding effects with detection and coarse discrimination of simple visual features. The present study tests the generality of this idea. A target Gabor patch, surrounded by either 2 or 6 flanker Gabors, was presented briefly at 4 deg eccentricity of the visual field. Each Gabor patch was oriented either vertically or horizontally (selected randomly). Observers' task was either to detect the presence of the target (presented with probability 0.5) or to identify the orientation of the target. The target-flanker distance was varied. Results were similar for the two tasks but different for 2 and 6 flankers. The idea that feature detection and coarse discrimination are immune to crowding may be valid for the two-flanker condition only. With six flankers, a normal crowding effect was observed. It is suggested that the complexity of the full pattern (target plus flankers) could explain the difference.

Iatrogenic water intoxication during pelvic ultrasonography in a patient with diabetes insipidus.

PubMed

Derinöz, Okşan; Emeksiz, Hamdi Cihan; Kalkan, Gökhan; Camurdan, Orhun

2012-01-01

Pelvic ultrasonography (US) is a simple and non-invasive radiologic test to evaluate the pelvic organs. It requires a full bladder for better visualization. Our case is a 14-year-old female with diabetes insipidus (DI) who admitted to the pediatric emergency service with the complaints of seizure and agitation after drinking 4 liters of water in one hour for a pelvic US examination due to work-up for delayed puberty. Her biochemical and clinical evaluation revealed water intoxication (WI). To our knowledge, this is the first WI case developed in a patient with DI. Here, we discuss the underlying factors leading to this complication and recommended an approach to obtain a better sonographic image without necessitating oral water intake to fill the urinary bladder.

[Diagnosis of ambiguous genitalia].

PubMed

de Sanctis, C; Einaudi, S; De Sanctis, L

1990-03-01

Diagnosis in patients with ambiguous genitalia is based on various investigations. Simple genital examination is not sufficient to attribute sex. Scarce androgenization in a male patient or marked androgenization in a female may both lead to the same stages of genital ambiguity according to Prader. It is important to get information about genital ambiguity in the family, drug consumption during gestation and signs of virilization in pregnant mothers. External genital findings must be integrated by visualization of urogenital sinus by X-rays, ultrasounds and endoscopy. Furthermore, hormonal evaluations on plasma and 24 hours urines allow diagnosis of some disorders of adrenal and gonadal steroidogenesis. To define genetic sex, chromosomal examination is required to integrate X chromatine investigation and fluorescent staining of Y chromosome. Evaluation of psychosexuality in patients who have already got gender identity is mandatory.

Visualization of small scale structures on high resolution DEMs

NASA Astrophysics Data System (ADS)

Kokalj, Žiga; Zakšek, Klemen; Pehani, Peter; Čotar, Klemen; Oštir, Krištof

2015-04-01

Knowledge on the terrain morphology is very important for observation of numerous processes and events and digital elevation models are therefore one of the most important datasets in geographic analyses. Furthermore, recognition of natural and anthropogenic microrelief structures, which can be observed on detailed terrain models derived from aerial laser scanning (lidar) or structure-from-motion photogrammetry, is of paramount importance in many applications. In this paper we thus examine and evaluate methods of raster lidar data visualization for the determination (recognition) of microrelief features and present a series of strategies to assist selecting the preferred visualization of choice for structures of various shapes and sizes, set in varied landscapes. Often the answer is not definite and more frequently a combination of techniques has to be used to map a very diverse landscape. Researchers can only very recently benefit from free software for calculation of advanced visualization techniques. These tools are often difficult to understand, have numerous options that confuse the user, or require and produce non-standard data formats, because they were written for specific purposes. We therefore designed the Relief Visualization Toolbox (RVT) as a free, easy-to-use, standalone application to create visualisations from high-resolution digital elevation data. It is tailored for the very beginners in relief interpretation, but it can also be used by more advanced users in data processing and geographic information systems. It offers a range of techniques, such as simple hillshading and its derivatives, slope gradient, trend removal, positive and negative openness, sky-view factor, and anisotropic sky-view factor. All included methods have been proven to be effective for detection of small scale features and the default settings are optimised to accomplish this task. However, the usability of the tool goes beyond computation for visualization purposes, as sky-view factor, for example, is an essential variable in many fields, e.g. in meteorology. RVT produces two types of results: 1) the original files have a full range of values and are intended for further analyses in geographic information systems, 2) the simplified versions are histogram stretched for visualization purposes and saved as 8-bit GeoTIFF files. This means that they can be explored in non-GIS software, e.g. with simple picture viewers, which is essential when a larger community of non-specialists needs to be considered, e.g. in public collaborative projects. The tool recognizes all frequently used single band raster formats and supports elevation raster file data conversion.

No effects of power line frequency extremely low frequency electromagnetic field exposure on selected neurobehavior tests of workers inspecting transformers and distribution line stations versus controls.

PubMed

Li, Li; Xiong, De-fu; Liu, Jia-wen; Li, Zi-xin; Zeng, Guang-cheng; Li, Hua-liang

2014-03-01

We aimed to evaluate the interference of 50 Hz extremely low frequency electromagnetic field (ELF-EMF) occupational exposure on the neurobehavior tests of workers performing tour-inspection close to transformers and distribution power lines. Occupational short-term "spot" measurements were carried out. 310 inspection workers and 300 logistics staff were selected as exposure and control. The neurobehavior tests were performed through computer-based neurobehavior evaluation system, including mental arithmetic, curve coincide, simple visual reaction time, visual retention, auditory digit span and pursuit aiming. In 500 kV areas electric field intensity at 71.98% of total measured 590 spots were above 5 kV/m (national occupational standard), while in 220 kV areas electric field intensity at 15.69% of total 701 spots were above 5 kV/m. Magnetic field flux density at all the spots was below 1,000 μT (ICNIRP occupational standard). The neurobehavior score changes showed no statistical significance. Results of neurobehavior tests among different age, seniority groups showed no significant changes. Neurobehavior changes caused by daily repeated ELF-EMF exposure were not observed in the current study.

Adaptive Multilinear Tensor Product Wavelets

DOE PAGES

Weiss, Kenneth; Lindstrom, Peter

2015-08-12

Many foundational visualization techniques including isosurfacing, direct volume rendering and texture mapping rely on piecewise multilinear interpolation over the cells of a mesh. However, there has not been much focus within the visualization community on techniques that efficiently generate and encode globally continuous functions defined by the union of multilinear cells. Wavelets provide a rich context for analyzing and processing complicated datasets. In this paper, we exploit adaptive regular refinement as a means of representing and evaluating functions described by a subset of their nonzero wavelet coefficients. We analyze the dependencies involved in the wavelet transform and describe how tomore » generate and represent the coarsest adaptive mesh with nodal function values such that the inverse wavelet transform is exactly reproduced via simple interpolation (subdivision) over the mesh elements. This allows for an adaptive, sparse representation of the function with on-demand evaluation at any point in the domain. In conclusion, we focus on the popular wavelets formed by tensor products of linear B-splines, resulting in an adaptive, nonconforming but crack-free quadtree (2D) or octree (3D) mesh that allows reproducing globally continuous functions via multilinear interpolation over its cells.« less

The Pareidolia Test: A Simple Neuropsychological Test Measuring Visual Hallucination-Like Illusions

PubMed Central

Mamiya, Yasuyuki; Nishio, Yoshiyuki; Watanabe, Hiroyuki; Yokoi, Kayoko; Uchiyama, Makoto; Baba, Toru; Iizuka, Osamu; Kanno, Shigenori; Kamimura, Naoto; Kazui, Hiroaki; Hashimoto, Mamoru; Ikeda, Manabu; Takeshita, Chieko; Shimomura, Tatsuo; Mori, Etsuro

2016-01-01

Background Visual hallucinations are a core clinical feature of dementia with Lewy bodies (DLB), and this symptom is important in the differential diagnosis and prediction of treatment response. The pareidolia test is a tool that evokes visual hallucination-like illusions, and these illusions may be a surrogate marker of visual hallucinations in DLB. We created a simplified version of the pareidolia test and examined its validity and reliability to establish the clinical utility of this test. Methods The pareidolia test was administered to 52 patients with DLB, 52 patients with Alzheimer’s disease (AD) and 20 healthy controls (HCs). We assessed the test-retest/inter-rater reliability using the intra-class correlation coefficient (ICC) and the concurrent validity using the Neuropsychiatric Inventory (NPI) hallucinations score as a reference. A receiver operating characteristic (ROC) analysis was used to evaluate the sensitivity and specificity of the pareidolia test to differentiate DLB from AD and HCs. Results The pareidolia test required approximately 15 minutes to administer, exhibited good test-retest/inter-rater reliability (ICC of 0.82), and moderately correlated with the NPI hallucinations score (rs = 0.42). Using an optimal cut-off score set according to the ROC analysis, and the pareidolia test differentiated DLB from AD with a sensitivity of 81% and a specificity of 92%. Conclusions Our study suggests that the simplified version of the pareidolia test is a valid and reliable surrogate marker of visual hallucinations in DLB. PMID:27171377

Prevalence of refractive error and visual impairment among rural school-age children of Goro District, Gurage Zone, Ethiopia.

PubMed

Kedir, Jafer; Girma, Abonesh

2014-10-01

Refractive error is one of the major causes of blindness and visual impairment in children; but community based studies are scarce especially in rural parts of Ethiopia. So, this study aims to assess the prevalence of refractive error and its magnitude as a cause of visual impairment among school-age children of rural community. This community-based cross-sectional descriptive study was conducted from March 1 to April 30, 2009 in rural villages of Goro district of Gurage Zone, found south west of Addis Ababa, the capital of Ethiopia. A multistage cluster sampling method was used with simple random selection of representative villages in the district. Chi-Square and t-tests were used in the data analysis. A total of 570 school-age children (age 7-15) were evaluated, 54% boys and 46% girls. The prevalence of refractive error was 3.5% (myopia 2.6% and hyperopia 0.9%). Refractive error was the major cause of visual impairment accounting for 54% of all causes in the study group. No child was found wearing corrective spectacles during the study period. Refractive error was the commonest cause of visual impairment in children of the district, but no measures were taken to reduce the burden in the community. So, large scale community level screening for refractive error should be conducted and integrated with regular school eye screening programs. Effective strategies need to be devised to provide low cost corrective spectacles in the rural community.

Zipf's word frequency law in natural language: a critical review and future directions.

PubMed

Piantadosi, Steven T

2014-10-01

The frequency distribution of words has been a key object of study in statistical linguistics for the past 70 years. This distribution approximately follows a simple mathematical form known as Zipf's law. This article first shows that human language has a highly complex, reliable structure in the frequency distribution over and above this classic law, although prior data visualization methods have obscured this fact. A number of empirical phenomena related to word frequencies are then reviewed. These facts are chosen to be informative about the mechanisms giving rise to Zipf's law and are then used to evaluate many of the theoretical explanations of Zipf's law in language. No prior account straightforwardly explains all the basic facts or is supported with independent evaluation of its underlying assumptions. To make progress at understanding why language obeys Zipf's law, studies must seek evidence beyond the law itself, testing assumptions and evaluating novel predictions with new, independent data.

SIMPLE: a sequential immunoperoxidase labeling and erasing method.

PubMed

Glass, George; Papin, Jason A; Mandell, James W

2009-10-01

The ability to simultaneously visualize expression of multiple antigens in cells and tissues can provide powerful insights into cellular and organismal biology. However, standard methods are limited to the use of just two or three simultaneous probes and have not been widely adopted for routine use in paraffin-embedded tissue. We have developed a novel approach called sequential immunoperoxidase labeling and erasing (SIMPLE) that enables the simultaneous visualization of at least five markers within a single tissue section. Utilizing the alcohol-soluble peroxidase substrate 3-amino-9-ethylcarbazole, combined with a rapid non-destructive method for antibody-antigen dissociation, we demonstrate the ability to erase the results of a single immunohistochemical stain while preserving tissue antigenicity for repeated rounds of labeling. SIMPLE is greatly facilitated by the use of a whole-slide scanner, which can capture the results of each sequential stain without any information loss.

Physics on Tap

ERIC Educational Resources Information Center

Wheeler, Andrew P. S.

2012-01-01

This article aims to describe how to visualize surface tension effects in liquid jets. A simple experiment is proposed using the liquid jet flow from a mains water tap/faucet. Using a modern digital camera with a high shutter speed, it is possible to visualize the instabilities (capillary waves) that form within the jet due to the action of…

Seeing Is Believing: Mathematics Visualization in Economics Education

ERIC Educational Resources Information Center

Johnson, Daniel K. N.

2007-01-01

Visualization through the use of physical objects is an important method that instructors can use to convey and solidify an understanding of economic principles in their novice students of economics. This paper outlines three simple examples which have been successful in the classroom, each taking a question that students frequently ask--why we…

Modified Matching Ronchi Test to Visualize Lens Aberrations

ERIC Educational Resources Information Center

Hassani, Kh; Ziafi, H. Hooshmand

2011-01-01

We introduce a modification to the matching Ronchi test to visualize lens aberrations with simple and inexpensive equipment available in educational optics labs. This method can help instructors and students to observe and estimate lens aberrations in real time. It is also a semi-quantitative tool for primary tests in research labs. In this work…

A Wheelchair User with Visual and Intellectual Disabilities Managing Simple Orientation Technology for Indoor Travel

ERIC Educational Resources Information Center

Lancioni, Giulio E.; O'Reilly, Mark F.; Singh, Nirbhay N.; Sigafoos, Jeff; Campodonico, Francesca; Oliva, Doretta

2009-01-01

Persons with profound visual impairments and other disabilities, such as neuromotor and intellectual disabilities, may encounter serious orientation and mobility problems even in familiar indoor environments, such as their homes. Teaching these persons to develop maps of their daily environment, using miniature replicas of the areas or some…

Similarity, Not Complexity, Determines Visual Working Memory Performance

ERIC Educational Resources Information Center

Jackson, Margaret C.; Linden, David E. J.; Roberts, Mark V.; Kriegeskorte, Nikolaus; Haenschel, Corinna

2015-01-01

A number of studies have shown that visual working memory (WM) is poorer for complex versus simple items, traditionally accounted for by higher information load placing greater demands on encoding and storage capacity limits. Other research suggests that it may not be complexity that determines WM performance per se, but rather increased…

Ink and Wash Painting for Children with Visual Impairment

ERIC Educational Resources Information Center

Shih, Chih-Ming; Chao, Hsin-Yi

2010-01-01

Five children with visual impairments received instruction in drawing, using ink and wash painting and calligraphy techniques. A special system developed by a blind Taiwanese Chinese calligrapher, Tsann-Cherng Liaw, was used to help the children orient and refine their work. Children's performance on simple drawing tasks was compared before and…

Developmental Reading Disorders in Japan--Prevalence, Profiles, and Possible Mechanisms

ERIC Educational Resources Information Center

Welty, Yumiko Tanaka; Menn, Lise; Oishi, Noriko

2014-01-01

Japan has been considered dyslexia-free because of the nature of the orthography, which consists of the visually simple kana syllabary and some thousands of visually complex, logographic kanji characters. It is true that few children struggle with learning kana, which provide consistent mappings between symbols and their pronunciation. Indeed,…

Motor Effects from Visually Induced Disorientation in Man.

ERIC Educational Resources Information Center

Brecher, M. Herbert; Brecher, Gerhard A.

The problem of disorientation in a moving optical environment was examined. A pilot can experience egocentric disorientation if the entire visual environment moves relative to his body without a clue as to the objectives position of the airplane in respect to the ground. A simple method of measuring disorientation was devised. In this method…

Parallel Consolidation of Simple Features into Visual Short-Term Memory

ERIC Educational Resources Information Center

Mance, Irida; Becker, Mark W.; Liu, Taosheng

2012-01-01

Although considerable research has examined the storage limits of visual short-term memory (VSTM), little is known about the initial formation (i.e., the consolidation) of VSTM representations. A few previous studies have estimated the capacity of consolidation to be one item at a time. Here we used a sequential-simultaneous manipulation to…

Neurophysiology and Neuroanatomy of Reflexive and Volitional Saccades: Evidence from Studies of Humans

ERIC Educational Resources Information Center

McDowell, Jennifer E.; Dyckman, Kara A.; Austin, Benjamin P.; Clementz, Brett A.

2008-01-01

This review provides a summary of the contributions made by human functional neuroimaging studies to the understanding of neural correlates of saccadic control. The generation of simple visually guided saccades (redirections of gaze to a visual stimulus or pro-saccades) and more complex volitional saccades require similar basic neural circuitry…

A Psychophysical Test of the Visual Pathway of Children with Autism

ERIC Educational Resources Information Center

Sanchez-Marin, Francisco J.; Padilla-Medina, Jose A.

2008-01-01

Signal detection psychophysical experiments were conducted to investigate the visual path of children with autism. Computer generated images with Gaussian noise were used. Simple signals, still and in motion were embedded in the background noise. The computer monitor was linearized to properly display the contrast changes. To our knowledge, this…

The Deceptively Simple N170 Reflects Network Information Processing Mechanisms Involving Visual Feature Coding and Transfer Across Hemispheres.

PubMed

Ince, Robin A A; Jaworska, Katarzyna; Gross, Joachim; Panzeri, Stefano; van Rijsbergen, Nicola J; Rousselet, Guillaume A; Schyns, Philippe G

2016-08-22

A key to understanding visual cognition is to determine "where", "when", and "how" brain responses reflect the processing of the specific visual features that modulate categorization behavior-the "what". The N170 is the earliest Event-Related Potential (ERP) that preferentially responds to faces. Here, we demonstrate that a paradigmatic shift is necessary to interpret the N170 as the product of an information processing network that dynamically codes and transfers face features across hemispheres, rather than as a local stimulus-driven event. Reverse-correlation methods coupled with information-theoretic analyses revealed that visibility of the eyes influences face detection behavior. The N170 initially reflects coding of the behaviorally relevant eye contralateral to the sensor, followed by a causal communication of the other eye from the other hemisphere. These findings demonstrate that the deceptively simple N170 ERP hides a complex network information processing mechanism involving initial coding and subsequent cross-hemispheric transfer of visual features. © The Author 2016. Published by Oxford University Press.

Young Skilled Deaf Readers Have an Enhanced Perceptual Span in Reading.

PubMed

Bélanger, Nathalie N; Lee, Michelle; Schotter, Elizabeth R

2017-04-27

Recently, Bélanger, Slattery, Mayberry and Rayner (2012) showed, using the moving window paradigm, that profoundly deaf adults have a wider perceptual span during reading relative to hearing adults matched on reading level. This difference might be related to the fact that deaf adults allocate more visual attention to simple stimuli in the parafovea (Bavelier, Dye & Hauser, 2006). Importantly, this reorganization of visual attention in deaf individuals is already manifesting in deaf children (Dye, Hauser & Bavelier, 2009). This leads to questions about the time course of the emergence of an enhanced perceptual span (which is under attentional control; Rayner, 2014; Miellet, O'Donnell, & Sereno, 2009) in young deaf readers. The present research addressed this question by comparing the perceptual spans of young deaf readers (age 7-15) and young hearing children (age 7-15). Young deaf readers, like deaf adults, were found to have a wider perceptual span relative to their hearing peers matched on reading level, suggesting that strong and early reorganization of visual attention in deaf individuals goes beyond the processing of simple visual stimuli and emerges into more cognitively complex tasks, such as reading.

A neural computational model for animal's time-to-collision estimation.

PubMed

Wang, Ling; Yao, Dezhong

2013-04-17

The time-to-collision (TTC) is the time elapsed before a looming object hits the subject. An accurate estimation of TTC plays a critical role in the survival of animals in nature and acts as an important factor in artificial intelligence systems that depend on judging and avoiding potential dangers. The theoretic formula for TTC is 1/τ≈θ'/sin θ, where θ and θ' are the visual angle and its variation, respectively, and the widely used approximation computational model is θ'/θ. However, both of these measures are too complex to be implemented by a biological neuronal model. We propose a new simple computational model: 1/τ≈Mθ-P/(θ+Q)+N, where M, P, Q, and N are constants that depend on a predefined visual angle. This model, weighted summation of visual angle model (WSVAM), can achieve perfect implementation through a widely accepted biological neuronal model. WSVAM has additional merits, including a natural minimum consumption and simplicity. Thus, it yields a precise and neuronal-implemented estimation for TTC, which provides a simple and convenient implementation for artificial vision, and represents a potential visual brain mechanism.

Brain activity during auditory and visual phonological, spatial and simple discrimination tasks.

PubMed

Salo, Emma; Rinne, Teemu; Salonen, Oili; Alho, Kimmo

2013-02-16

We used functional magnetic resonance imaging to measure human brain activity during tasks demanding selective attention to auditory or visual stimuli delivered in concurrent streams. Auditory stimuli were syllables spoken by different voices and occurring in central or peripheral space. Visual stimuli were centrally or more peripherally presented letters in darker or lighter fonts. The participants performed a phonological, spatial or "simple" (speaker-gender or font-shade) discrimination task in either modality. Within each modality, we expected a clear distinction between brain activations related to nonspatial and spatial processing, as reported in previous studies. However, within each modality, different tasks activated largely overlapping areas in modality-specific (auditory and visual) cortices, as well as in the parietal and frontal brain regions. These overlaps may be due to effects of attention common for all three tasks within each modality or interaction of processing task-relevant features and varying task-irrelevant features in the attended-modality stimuli. Nevertheless, brain activations caused by auditory and visual phonological tasks overlapped in the left mid-lateral prefrontal cortex, while those caused by the auditory and visual spatial tasks overlapped in the inferior parietal cortex. These overlapping activations reveal areas of multimodal phonological and spatial processing. There was also some evidence for intermodal attention-related interaction. Most importantly, activity in the superior temporal sulcus elicited by unattended speech sounds was attenuated during the visual phonological task in comparison with the other visual tasks. This effect might be related to suppression of processing irrelevant speech presumably distracting the phonological task involving the letters. Copyright © 2012 Elsevier B.V. All rights reserved.

Information Visualization Techniques for Effective Cross-Discipline Communication

NASA Astrophysics Data System (ADS)

Fisher, Ward

2013-04-01

Collaboration between research groups in different fields is a common occurrence, but it can often be frustrating due to the absence of a common vocabulary. This lack of a shared context can make expressing important concepts and discussing results difficult. This problem may be further exacerbated when communicating to an audience of laypeople. Without a clear frame of reference, simple concepts are often rendered difficult-to-understand at best, and unintelligible at worst. An easy way to alleviate this confusion is with the use of clear, well-designed visualizations to illustrate an idea, process or conclusion. There exist a number of well-described machine-learning and statistical techniques which can be used to illuminate the information present within complex high-dimensional datasets. Once the information has been separated from the data, clear communication becomes a matter of selecting an appropriate visualization. Ideally, the visualization is information-rich but data-scarce. Anything from a simple bar chart, to a line chart with confidence intervals, to an animated set of 3D point-clouds can be used to render a complex idea as an easily understood image. Several case studies will be presented in this work. In the first study, we will examine how a complex statistical analysis was applied to a high-dimensional dataset, and how the results were succinctly communicated to an audience of microbiologists and chemical engineers. Next, we will examine a technique used to illustrate the concept of the singular value decomposition, as used in the field of computer vision, to a lay audience of undergraduate students from mixed majors. We will then examine a case where a simple animated line plot was used to communicate an approach to signal decomposition, and will finish with a discussion of the tools available to create these visualizations.

Comparing Motor Skills in Autism Spectrum Individuals With and Without Speech Delay

PubMed Central

Barbeau, Elise B.; Meilleur, Andrée‐Anne S.; Zeffiro, Thomas A.

2015-01-01

Movement atypicalities in speed, coordination, posture, and gait have been observed across the autism spectrum (AS) and atypicalities in coordination are more commonly observed in AS individuals without delayed speech (DSM‐IV Asperger) than in those with atypical or delayed speech onset. However, few studies have provided quantitative data to support these mostly clinical observations. Here, we compared perceptual and motor performance between 30 typically developing and AS individuals (21 with speech delay and 18 without speech delay) to examine the associations between limb movement control and atypical speech development. Groups were matched for age, intelligence, and sex. The experimental design included: an inspection time task, which measures visual processing speed; the Purdue Pegboard, which measures finger dexterity, bimanual performance, and hand‐eye coordination; the Annett Peg Moving Task, which measures unimanual goal‐directed arm movement; and a simple reaction time task. We used analysis of covariance to investigate group differences in task performance and linear regression models to explore potential associations between intelligence, language skills, simple reaction time, and visually guided movement performance. AS participants without speech delay performed slower than typical participants in the Purdue Pegboard subtests. AS participants without speech delay showed poorer bimanual coordination than those with speech delay. Visual processing speed was slightly faster in both AS groups than in the typical group. Altogether, these results suggest that AS individuals with and without speech delay differ in visually guided and visually triggered behavior and show that early language skills are associated with slower movement in simple and complex motor tasks. Autism Res 2015, 8: 682–693. © 2015 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research PMID:25820662

Surfing-related ocular injuries.

PubMed

Kim, J W; McDonald, H R; Rubsamen, P E; Luttrull, J K; Drouilhet, J H; Frambach, D A; Boyer, D S; Lambrou, F H; Hendrick, A; Weiss, J N; Engstrom, R E; Ing, M

1998-01-01

This report evaluates the clinical characteristics of surfing-related ocular trauma to learn the nature of such injuries and propose possible preventive measures. The authors reviewed 11 cases of surfing-related eye injuries caused by direct trauma from the surfboard, studying their mechanism of injury, the associated ocular complications, and the anatomic and visual outcomes of surgical repair. Surfing-related ocular injuries occurred exclusively in young males (mean age, 24.8 years; range, 14-37 years). The mechanism of injury most frequently responsible was impact with the sharp nose of the surfboard following a fall. Serious posterior segment complications were observed in all 11 patients, with nine patients suffering ruptured globes. Despite immediate medical attention, five patients did not recover ambulatory levels of visual acuity (>5/200). Surfing-related ocular trauma presenting to the retinal specialist typically leaves the patient with a permanent visual disability. Important factors contributing to these high-velocity injuries include the sharply pointed nose of the surfboard and the leash keeping the surfer in close proximity to the board following a fall. A simple modification in surfboard design such as blunting the sharp nose of the surfboard, or appropriate protective guards fitted over the surfboard nose, should lessen the severity of such injuries.

Relating Neuronal to Behavioral Performance: Variability of Optomotor Responses in the Blowfly

PubMed Central

Rosner, Ronny; Warzecha, Anne-Kathrin

2011-01-01

Behavioral responses of an animal vary even when they are elicited by the same stimulus. This variability is due to stochastic processes within the nervous system and to the changing internal states of the animal. To what extent does the variability of neuronal responses account for the overall variability at the behavioral level? To address this question we evaluate the neuronal variability at the output stage of the blowfly's (Calliphora vicina) visual system by recording from motion-sensitive interneurons mediating head optomotor responses. By means of a simple modelling approach representing the sensory-motor transformation, we predict head movements on the basis of the recorded responses of motion-sensitive neurons and compare the variability of the predicted head movements with that of the observed ones. Large gain changes of optomotor head movements have previously been shown to go along with changes in the animals' activity state. Our modelling approach substantiates that these gain changes are imposed downstream of the motion-sensitive neurons of the visual system. Moreover, since predicted head movements are clearly more reliable than those actually observed, we conclude that substantial variability is introduced downstream of the visual system. PMID:22066014

Clinical pharmacology of sibutramine hydrochloride (BTS 54524), a new antidepressant, in healthy volunteers.

PubMed Central

King, D J; Devaney, N

1988-01-01

The cardiovascular, anticholinergic and central effects of single doses of 30, 45 and 60 mg of sibutramine hydrochloride (BTS 54524), a new potential antidepressant, were compared with amitriptyline (50 mg) and placebo given at weekly intervals in a randomised design to six healthy male volunteers. Sibutramine was associated with increases in both supine heart rate and systolic blood pressure at 1, 2 and 6 h after 60 mg (P less than 0.05). Amitriptyline caused a significant 50-60% decrease in salivation compared with placebo at 2 and 6 h but there were no changes with sibutramine. No significant changes in pupil size were detected with either drug. Visual analogue rating scales (VARS) revealed significant drowsiness with amitriptyline but neither sedative nor stimulant effects with sibutramine. Impairments of simple auditory and visual reaction times, visual two-choice reaction time, finger tapping and trail making, measured using an automated test battery, occurred with amitriptyline compared with sibutramine. If sibutramine proves to be an effective antidepressant it should be devoid of anticholinergic or central depressant effects. Chronic dosage studies are indicated to evaluate the clinical significance of its cardiovascular effects. PMID:3207566

Multi Agent Reward Analysis for Learning in Noisy Domains

NASA Technical Reports Server (NTRS)

Tumer, Kagan; Agogino, Adrian K.

2005-01-01

In many multi agent learning problems, it is difficult to determine, a priori, the agent reward structure that will lead to good performance. This problem is particularly pronounced in continuous, noisy domains ill-suited to simple table backup schemes commonly used in TD(lambda)/Q-learning. In this paper, we present a new reward evaluation method that allows the tradeoff between coordination among the agents and the difficulty of the learning problem each agent faces to be visualized. This method is independent of the learning algorithm and is only a function of the problem domain and the agents reward structure. We then use this reward efficiency visualization method to determine an effective reward without performing extensive simulations. We test this method in both a static and a dynamic multi-rover learning domain where the agents have continuous state spaces and where their actions are noisy (e.g., the agents movement decisions are not always carried out properly). Our results show that in the more difficult dynamic domain, the reward efficiency visualization method provides a two order of magnitude speedup in selecting a good reward. Most importantly it allows one to quickly create and verify rewards tailored to the observational limitations of the domain.

Statistical modeling for visualization evaluation through data fusion.

PubMed

Chen, Xiaoyu; Jin, Ran

2017-11-01

There is a high demand of data visualization providing insights to users in various applications. However, a consistent, online visualization evaluation method to quantify mental workload or user preference is lacking, which leads to an inefficient visualization and user interface design process. Recently, the advancement of interactive and sensing technologies makes the electroencephalogram (EEG) signals, eye movements as well as visualization logs available in user-centered evaluation. This paper proposes a data fusion model and the application procedure for quantitative and online visualization evaluation. 15 participants joined the study based on three different visualization designs. The results provide a regularized regression model which can accurately predict the user's evaluation of task complexity, and indicate the significance of all three types of sensing data sets for visualization evaluation. This model can be widely applied to data visualization evaluation, and other user-centered designs evaluation and data analysis in human factors and ergonomics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Speech-based interaction with in-vehicle computers: the effect of speech-based e-mail on drivers' attention to the roadway.

PubMed

Lee, J D; Caven, B; Haake, S; Brown, T L

2001-01-01

As computer applications for cars emerge, a speech-based interface offers an appealing alternative to the visually demanding direct manipulation interface. However, speech-based systems may pose cognitive demands that could undermine driving safety. This study used a car-following task to evaluate how a speech-based e-mail system affects drivers' response to the periodic braking of a lead vehicle. The study included 24 drivers between the ages of 18 and 24 years. A baseline condition with no e-mail system was compared with a simple and a complex e-mail system in both simple and complex driving environments. The results show a 30% (310 ms) increase in reaction time when the speech-based system is used. Subjective workload ratings and probe questions also indicate that speech-based interaction introduces a significant cognitive load, which was highest for the complex e-mail system. These data show that a speech-based interface is not a panacea that eliminates the potential distraction of in-vehicle computers. Actual or potential applications of this research include design of in-vehicle information systems and evaluation of their contributions to driver distraction.

Is Fourier analysis performed by the visual system or by the visual investigator.

PubMed

Ochs, A L

1979-01-01

A numerical Fourier transform was made of the pincushion grid illusion and the spectral components orthogonal to the illusory lines were isolated. Their inverse transform creates a picture of the illusion. The spatial-frequency response of cortical, simple receptive field neurons similarly filters the grid. A complete set of these neurons thus approximates a two-dimensional Fourier analyzer. One cannot conclude, however, that the brain actually uses frequency-domain information to interpret visual images.

Singlet Oxygen at the Laundromat

NASA Astrophysics Data System (ADS)

Keeports, David

1995-09-01

Singlet molecular oxygen is an interesting molecule both visually and theoretically, since its red chemiluminescence can be analyzed by the application of simple molecular orbital theory. It can be produced from the reaction of hydrogen peroxide from either chlorine gas or hypochlorite ion from household bleach. Here we demostrate how to produce it using simple laundry cleansers.

The Box-and-Dot Method: A Simple Strategy for Counting Significant Figures

ERIC Educational Resources Information Center

Stephenson, W. Kirk

2009-01-01

A visual method for counting significant digits is presented. This easy-to-learn (and easy-to-teach) method, designated the box-and-dot method, uses the device of "boxing" significant figures based on two simple rules, then counting the number of digits in the boxes. (Contains 4 notes.)

Hooke's Law and the Stiffness of a Plastic Spoon

ERIC Educational Resources Information Center

Pestka, Kenneth A., II; Warren, Cori

2012-01-01

The study of elastic properties of solids is essential to both physics and engineering. Finding simple, easy-to-visualize examples to demonstrate these concepts is often difficult. In a previous article written by one of us (KAPII), a simple method for determining Youngs modulus using marshmallows was given. In this article we will illustrate…

Explicit criteria for prioritization of cataract surgery

PubMed Central

Ma Quintana, José; Escobar, Antonio; Bilbao, Amaia

2006-01-01

Background Consensus techniques have been used previously to create explicit criteria to prioritize cataract extraction; however, the appropriateness of the intervention was not included explicitly in previous studies. We developed a prioritization tool for cataract extraction according to the RAND method. Methods Criteria were developed using a modified Delphi panel judgment process. A panel of 11 ophthalmologists was assembled. Ratings were analyzed regarding the level of agreement among panelists. We studied the effect of all variables on the final panel score using general linear and logistic regression models. Priority scoring systems were developed by means of optimal scaling and general linear models. The explicit criteria developed were summarized by means of regression tree analysis. Results Eight variables were considered to create the indications. Of the 310 indications that the panel evaluated, 22.6% were considered high priority, 52.3% intermediate priority, and 25.2% low priority. Agreement was reached for 31.9% of the indications and disagreement for 0.3%. Logistic regression and general linear models showed that the preoperative visual acuity of the cataractous eye, visual function, and anticipated visual acuity postoperatively were the most influential variables. Alternative and simple scoring systems were obtained by optimal scaling and general linear models where the previous variables were also the most important. The decision tree also shows the importance of the previous variables and the appropriateness of the intervention. Conclusion Our results showed acceptable validity as an evaluation and management tool for prioritizing cataract extraction. It also provides easy algorithms for use in clinical practice. PMID:16512893

Influence of regular proprioceptive and bioenergetic physical activities on balance control in elderly women.

PubMed

Gauchard, Gérome C; Gangloff, Pierre; Jeandel, Claude; Perrin, Philippe P

2003-09-01

Balance disorders increase considerably with age due to a decrease in posture regulation quality, and are accompanied by a higher risk of falling. Conversely, physical activities have been shown to improve the quality of postural control in elderly individuals and decrease the number of falls. The aim of this study was to evaluate the impact of two types of exercise on the visual afferent and on the different parameters of static balance regulation. Static postural control was evaluated in 44 healthy women aged over 60 years. Among them, 15 regularly practiced proprioceptive physical activities (Group I), 12 regularly practiced bioenergetic physical activities (Group II), and 18 controls walked on a regular basis (Group III). Group I participants displayed lower sway path and area values, whereas Group III participants displayed the highest, both in eyes-open and eyes-closed conditions. Group II participants displayed intermediate values, close to those of Group I in the eyes-open condition and those of Group III in the eyes-closed condition. Visual afferent contribution was more pronounced for Group II and III participants than for Group I participants. Proprioceptive exercise appears to have the best impact on balance regulation and precision. Besides, even if bioenergetic activity improves postural control in simple postural tasks, more difficult postural tasks show that this type of activity does not develop a neurosensorial proprioceptive input threshold as well, probably on account of the higher contribution of visual afferent.

Design and validation of a method for evaluation of interocular interaction.

PubMed

Lai, Xin Jie Angela; Alexander, Jack; Ho, Arthur; Yang, Zhikuan; He, Mingguang; Suttle, Catherine

2012-02-01

To design a simple viewing system allowing dichoptic masking, and to validate this system in adults and children with normal vision. A Trial Frame Apparatus (TFA) was designed to evaluate interocular interaction. This device consists of a trial frame, a 1 mm pinhole in front of the tested eye and a full or partial occluder in front of the non-tested eye. The difference in visual function in one eye between the full- and partial-occlusion conditions was termed the Interaction Index. In experiment 1, low-contrast acuity was measured in six adults using five types of partial occluder. Interaction Index was compared between these five, and the occluder showing the highest Index was used in experiment 2. In experiment 2, low-contrast acuity, contrast sensitivity, and alignment sensitivity were measured in the non-dominant eye of 45 subjects (15 older adults, 15 young adults, and 15 children), using the TFA and an existing well-validated device (shutter goggles) with full and partial occlusion of the dominant eye. These measurements were repeated on 11 subjects of each group using TFA in the partial-occlusion condition only. Repeatability of visual function measurements using TFA was assessed using the Bland-Altman method and agreement between TFA and goggles in terms of visual functions and interactions was assessed using the Bland-Altman method and t-test. In all three subject groups, the TFA showed a high level of repeatability in all visual function measurements. Contrast sensitivity was significantly poorer when measured using TFA than using goggles (p < 0.05). However, Interaction Index of all three visual functions showed acceptable agreement between TFA and goggles (p > 0.05). The TFA may provide an acceptable method for the study of some forms of dichoptic masking in populations where more complex devices (e.g., shutter goggles) cannot be used.

Cephalopod consciousness: behavioural evidence.

PubMed

Mather, Jennifer A

2008-03-01

Behavioural evidence suggests that cephalopod molluscs may have a form of primary consciousness. First, the linkage of brain to behaviour seen in lateralization, sleep and through a developmental context is similar to that of mammals and birds. Second, cephalopods, especially octopuses, are heavily dependent on learning in response to both visual and tactile cues, and may have domain generality and form simple concepts. Third, these animals are aware of their position, both within themselves and in larger space, including having a working memory of foraging areas in the recent past. Thus if using a 'global workspace' which evaluates memory input and focuses attention is the criterion, cephalopods appear to have primary consciousness.

Validation of Simple Quantification Methods for (18)F-FP-CIT PET Using Automatic Delineation of Volumes of Interest Based on Statistical Probabilistic Anatomical Mapping and Isocontour Margin Setting.

PubMed

Kim, Yong-Il; Im, Hyung-Jun; Paeng, Jin Chul; Lee, Jae Sung; Eo, Jae Seon; Kim, Dong Hyun; Kim, Euishin E; Kang, Keon Wook; Chung, June-Key; Lee, Dong Soo

2012-12-01

(18)F-FP-CIT positron emission tomography (PET) is an effective imaging for dopamine transporters. In usual clinical practice, (18)F-FP-CIT PET is analyzed visually or quantified using manual delineation of a volume of interest (VOI) for the striatum. In this study, we suggested and validated two simple quantitative methods based on automatic VOI delineation using statistical probabilistic anatomical mapping (SPAM) and isocontour margin setting. Seventy-five (18)F-FP-CIT PET images acquired in routine clinical practice were used for this study. A study-specific image template was made and the subject images were normalized to the template. Afterwards, uptakes in the striatal regions and cerebellum were quantified using probabilistic VOI based on SPAM. A quantitative parameter, QSPAM, was calculated to simulate binding potential. Additionally, the functional volume of each striatal region and its uptake were measured in automatically delineated VOI using isocontour margin setting. Uptake-volume product (QUVP) was calculated for each striatal region. QSPAM and QUVP were compared with visual grading and the influence of cerebral atrophy on the measurements was tested. Image analyses were successful in all the cases. Both the QSPAM and QUVP were significantly different according to visual grading (P < 0.001). The agreements of QUVP or QSPAM with visual grading were slight to fair for the caudate nucleus (κ = 0.421 and 0.291, respectively) and good to perfect to the putamen (κ = 0.663 and 0.607, respectively). Also, QSPAM and QUVP had a significant correlation with each other (P < 0.001). Cerebral atrophy made a significant difference in QSPAM and QUVP of the caudate nuclei regions with decreased (18)F-FP-CIT uptake. Simple quantitative measurements of QSPAM and QUVP showed acceptable agreement with visual grading. Although QSPAM in some group may be influenced by cerebral atrophy, these simple methods are expected to be effective in the quantitative analysis of (18)F-FP-CIT PET in usual clinical practice.

Laser-assisted in situ keratomileusis with optimized, fast-repetition, and cyclotorsion control excimer laser to treat hyperopic astigmatism with high cylinder.

PubMed

Alió Del Barrio, Jorge L; Tiveron, Mauro; Plaza-Puche, Ana B; Amesty, María A; Casanova, Laura; García, María J; Alió, Jorge L

2017-10-18

To evaluate the visual outcomes after femtosecond laser-assisted laser in situ keratomileusis (LASIK) surgery to correct primary compound hyperopic astigmatism with high cylinder using a fast repetition rate excimer laser platform with optimized aspheric profiles and cyclotorsion control. Eyes with primary simple or compound hyperopic astigmatism and a cylinder power ≥3.00 D had uneventful femtosecond laser-assisted LASIK with a fast repetition rate excimer laser ablation, aspheric profiles, and cyclotorsion control. Visual, refractive, and aberrometric results were evaluated at the 3- and 6-month follow-up. The astigmatic outcome was evaluated using the Alpins method and ASSORT software. This study enrolled 80 eyes at 3 months and 50 eyes at 6 months. The significant reduction in refractive sphere and cylinder 3 and 6 months postoperatively (p<0.01) was associated with an improved uncorrected distance visual acuity (p<0.01). A total of 23.75% required retreatment 3 months after surgery. Efficacy and safety indices at 6 months were 0.90 and 1.00, respectively. At 6 months, 80% of eyes had an SE within ±0.50 D and 96% within ±1.00 D. No significant differences were detected between the third and the sixth postoperative months in refractive parameters. A significant increase in the spherical aberration was detected, but not in coma. The correction index was 0.94 at 3 months. Laser in situ keratomileusis for primary compound hyperopic astigmatism with high cylinder (>3.00 D) using the latest excimer platforms with cyclotorsion control, fast repetition rate, and optimized aspheric profiles is safe, moderately effective, and predictable.

Does Presentation Format Influence Visual Size Discrimination in Tufted Capuchin Monkeys (Sapajus spp.)?

PubMed Central

Truppa, Valentina; Carducci, Paola; Trapanese, Cinzia; Hanus, Daniel

2015-01-01

Most experimental paradigms to study visual cognition in humans and non-human species are based on discrimination tasks involving the choice between two or more visual stimuli. To this end, different types of stimuli and procedures for stimuli presentation are used, which highlights the necessity to compare data obtained with different methods. The present study assessed whether, and to what extent, capuchin monkeys’ ability to solve a size discrimination problem is influenced by the type of procedure used to present the problem. Capuchins’ ability to generalise knowledge across different tasks was also evaluated. We trained eight adult tufted capuchin monkeys to select the larger of two stimuli of the same shape and different sizes by using pairs of food items (Experiment 1), computer images (Experiment 1) and objects (Experiment 2). Our results indicated that monkeys achieved the learning criterion faster with food stimuli compared to both images and objects. They also required consistently fewer trials with objects than with images. Moreover, female capuchins had higher levels of acquisition accuracy with food stimuli than with images. Finally, capuchins did not immediately transfer the solution of the problem acquired in one task condition to the other conditions. Overall, these findings suggest that – even in relatively simple visual discrimination problems where a single perceptual dimension (i.e., size) has to be judged – learning speed strongly depends on the mode of presentation. PMID:25927363

The language of arithmetic across the hemispheres: An event-related potential investigation.

PubMed

Dickson, Danielle S; Federmeier, Kara D

2017-05-01

Arithmetic expressions, like verbal sentences, incrementally lead readers to anticipate potential appropriate completions. Existing work in the language domain has helped us understand how the two hemispheres differently participate in and contribute to the cognitive process of sentence reading, but comparatively little work has been done with mathematical equation processing. In this study, we address this gap by examining the ERP response to provided answers to simple multiplication problems, which varied both in levels of correctness (given an equation context) and in visual field of presentation (joint attention in central presentation, or biased processing to the left or right hemisphere through contralateral visual field presentation). When answers were presented to any of the visual fields (hemispheres), there was an effect of correctness prior to the traditional N400 timewindow, which we interpret as a P300 in response to a detected target item (the correct answer). In addition to this response, equation answers also elicited a late positive complex (LPC) for incorrect answers. Notably, this LPC effect was most prominent in the left visual field (right hemisphere), and it was also sensitive to the confusability of the wrong answer - incorrect answers that were closely related to the correct answer elicited a smaller LPC. This suggests a special, prolonged role for the right hemisphere during answer evaluation. Copyright © 2017 Elsevier B.V. All rights reserved.

Visualization of atomic-scale phenomena in superconductors: application to FeSe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choubey, Peayush; Berlijn, Tom; Kreisel, Andreas

Here we propose a simple method of calculating inhomogeneous, atomic-scale phenomena in superconductors which makes use of the wave function information traditionally discarded in the construction of tight-binding models used in the Bogoliubov-de Gennes equations. The method uses symmetry- based first principles Wannier functions to visualize the effects of superconducting pairing on the distribution of electronic states over atoms within a crystal unit cell. Local symmetries lower than the global lattice symmetry can thus be exhibited as well, rendering theoretical comparisons with scanning tunneling spectroscopy data much more useful. As a simple example, we discuss the geometric dimer states observedmore » near defects in superconducting FeSe.« less

Visualization of atomic-scale phenomena in superconductors: application to FeSe

DOE PAGES

Choubey, Peayush; Berlijn, Tom; Kreisel, Andreas; ...

2014-10-31

Here we propose a simple method of calculating inhomogeneous, atomic-scale phenomena in superconductors which makes use of the wave function information traditionally discarded in the construction of tight-binding models used in the Bogoliubov-de Gennes equations. The method uses symmetry- based first principles Wannier functions to visualize the effects of superconducting pairing on the distribution of electronic states over atoms within a crystal unit cell. Local symmetries lower than the global lattice symmetry can thus be exhibited as well, rendering theoretical comparisons with scanning tunneling spectroscopy data much more useful. As a simple example, we discuss the geometric dimer states observedmore » near defects in superconducting FeSe.« less

A Probabilistic Model of Visual Working Memory: Incorporating Higher Order Regularities into Working Memory Capacity Estimates

ERIC Educational Resources Information Center

Brady, Timothy F.; Tenenbaum, Joshua B.

2013-01-01

When remembering a real-world scene, people encode both detailed information about specific objects and higher order information like the overall gist of the scene. However, formal models of change detection, like those used to estimate visual working memory capacity, assume observers encode only a simple memory representation that includes no…

Visual Short-Term Memory Capacity for Simple and Complex Objects

ERIC Educational Resources Information Center

Luria, Roy; Sessa, Paola; Gotler, Alex; Jolicoeur, Pierre; Dell'Acqua, Roberto

2010-01-01

Does the capacity of visual short-term memory (VSTM) depend on the complexity of the objects represented in memory? Although some previous findings indicated lower capacity for more complex stimuli, other results suggest that complexity effects arise during retrieval (due to errors in the comparison process with what is in memory) that is not…

The Effect of Ionic Strength on the Solubility of an Electrolyte

ERIC Educational Resources Information Center

Willey, Joan D.

2004-01-01

A simple experiment was conducted for studying and demonstrating visually and dramatically the effect of ionic strength on the solubility of an electrolyte is described. It is seen that the experiment visually illustrates the effect of ionic strength on electrolyte solubility by the appearance of the two solutions and by the difference in the…

Fluorescence Aggregation-Caused Quenching versus Aggregation-Induced Emission: A Visual Teaching Technology for Undergraduate Chemistry Students

ERIC Educational Resources Information Center

Ma, Xiaofeng; Sun, Rui; Cheng, Jinghui; Liu, Jiaoyan; Gou, Fei; Xiang, Haifeng; Zhou, Xiangge

2016-01-01

A laboratory experiment visually exploring two opposite basic principles of fluorescence of aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) is demonstrated. The students would prepared two salicylaldehyde-based Schiff bases through a simple one-pot condensation reaction of one equiv of 1,2-diamine with 2 equiv of…

Semantically Induced Distortions of Visual Awareness in a Patient with Balint's Syndrome

ERIC Educational Resources Information Center

Soto, David; Humphreys, Glyn W.

2009-01-01

We present data indicating that visual awareness for a basic perceptual feature (colour) can be influenced by the relation between the feature and the semantic properties of the stimulus. We examined semantic interference from the meaning of a colour word ("RED") on simple colour (ink related) detection responses in a patient with simultagnosia…

An Optimized Centrifugal Method for Separation of Semen from Superabsorbent Polymers for Forensic Analysis.

PubMed

Camarena, Lucy R; Glasscock, Bailey K; Daniels, Demi; Ackley, Nicolle; Sciarretta, Marybeth; Seashols-Williams, Sarah J

2017-03-01

Connection of a perpetrator to a sexual assault is best performed through the confirmed presence of semen, thereby proving sexual contact. Evidentiary items can include sanitary napkins or diapers containing superabsorbent polymers (SAPs), complicating spermatozoa visualization and DNA analysis. In this report, we evaluated the impact of SAPS on the current forensic DNA workflow, developing an efficient centrifugal protocol for separating spermatozoa from SAP material. The optimized filtration method was compared to common practices of excising the top layer only, resulting in significantly higher sperm yields when a core sample of the substrate was taken. Direct isolation of the SAP-containing materials without filtering resulted in 20% sample failure; additionally, SAP material was observed in the final eluted DNA samples, causing physical interference. Thus, use of the described centrifugal-filtering method is a simple preliminary step that improves spermatozoa visualization and enables more consistent DNA yields, while also avoiding SAP interference. © 2016 American Academy of Forensic Sciences.

Excel2Genie: A Microsoft Excel application to improve the flexibility of the Genie-2000 Spectroscopic software.

PubMed

Forgács, Attila; Balkay, László; Trón, Lajos; Raics, Péter

2014-12-01

Excel2Genie, a simple and user-friendly Microsoft Excel interface, has been developed to the Genie-2000 Spectroscopic Software of Canberra Industries. This Excel application can directly control Canberra Multichannel Analyzer (MCA), process the acquired data and visualize them. Combination of Genie-2000 with Excel2Genie results in remarkably increased flexibility and a possibility to carry out repetitive data acquisitions even with changing parameters and more sophisticated analysis. The developed software package comprises three worksheets: display parameters and results of data acquisition, data analysis and mathematical operations carried out on the measured gamma spectra. At the same time it also allows control of these processes. Excel2Genie is freely available to assist gamma spectrum measurements and data evaluation by the interested Canberra users. With access to the Visual Basic Application (VBA) source code of this application users are enabled to modify the developed interface according to their intentions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Application of NASA Giovanni to Coastal Zone Remote Sensing Research

NASA Technical Reports Server (NTRS)

Acker, James; Leptoukh, Gregory; Kempler, Steven; Berrick, Stephen; Rui, Hualan; Shen, Suhung

2007-01-01

The Goddard Earth Sciences Data and Information Services Center (GES DISC) Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) provides rapid access to, and enables effective utilization of, remotely-sensed data that are applicable to investigations of coastal environmental processes. Data sets in Giovanni include precipitation data from the Tropical Rainfall Measuring Mission (TRMM), particularly useful for coastal storm investigations; ocean color radiometry data from the Sea-viewing Wide Field-of-view Sensor (SeaWIFS) and Moderate Resolution Imaging Spectroradiometer (MODIS), useful for water quality evaluation, phytoplankton blooms, and terrestrial-marine interactions; and atmospheric data from MODIS and the Advanced Infrared Sounder (AIRS), providing the capability to characterize atmospheric variables. Giovanni provides a simple interface allowing discovery and analysis of environmental data sets with accompanying graphic visualizations. Examples of Giovanni investigations of the coastal zone include hurricane and storm impacts, hydrologically-induced phytoplankton blooms, chlorophyll trend analysis, and dust storm characterization. New and near-future capabilities of Giovanni will be described.

Application of NASA Giovanni to Coastal Zone Remote Sensing Search

NASA Technical Reports Server (NTRS)

Acker, James; Leptoukh, Gregory; Kempler, Steven; Berrick, Stephen; Rui, Hualan; Shen, Suhung

2007-01-01

The Goddard Earth Sciences Data and Information Services Center (GES DISC) Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) provides rapid access to, and enables effective utilization of, remotely-sensed data that are applicable to investigations of coastal environmental processes. Data sets in Giovanni include precipitation data from the Tropical Rainfall Measuring Mission (TRMM), particularly useful for coastal storm investigations; ocean color radiometry data from the Sea-viewing Wide Field-of-view Sensor (SeaWIFS) and Moderate Resolution Imaging Spectroradiometer (MODIS), useful for water quality evaluation, phytoplankton blooms, and terrestrial-marine interactions; and atmospheric data from MODIS and the Advanced Infrared Sounder (AIRS), providing the capability to characterize atmospheric variables. Giovanni provides a simple interface allowing discovery and analysis of environmental data sets with accompanying graphic visualizations. Examples of Giovanni investigations of the coastal zone include hurricane and storm impacts, hydrologically-induced phytoplankton blooms, chlorophyll trend analysis, and dust storm characterization. New and near-future capabilities of Giovanni will be described.

Visual communication in presentation on physics

NASA Astrophysics Data System (ADS)

Grebenyuk, Konstantin A.

2005-06-01

It is essential that our audience be attentive during lecture, report or another presentation on physics. Therefore we have to take care of both speech and visual communication with audience. Three important aspects of successful visual aids use are singled out in this paper. The main idea is that physicists could appreciably increase efficiency of their presentations by use of these simple principles of presentation art. Recommendations offered are results of special literature research, author' s observations and experience of communication with skilled masters of presentations.

How the blind "see" Braille: lessons from functional magnetic resonance imaging.

PubMed

Sadato, Norihiro

2005-12-01

What does the visual cortex of the blind do during Braille reading? This process involves converting simple tactile information into meaningful patterns that have lexical and semantic properties. The perceptual processing of Braille might be mediated by the somatosensory system, whereas visual letter identity is accomplished within the visual system in sighted people. Recent advances in functional neuroimaging techniques, such as functional magnetic resonance imaging, have enabled exploration of the neural substrates of Braille reading. The primary visual cortex of early-onset blind subjects is functionally relevant to Braille reading, suggesting that the brain shows remarkable plasticity that potentially permits the additional processing of tactile information in the visual cortical areas.

Expected Utility Illustrated: A Graphical Analysis of Gambles with More than Two Possible Outcomes

ERIC Educational Resources Information Center

Chen, Frederick H.

2010-01-01

The author presents a simple geometric method to graphically illustrate the expected utility from a gamble with more than two possible outcomes. This geometric result gives economics students a simple visual aid for studying expected utility theory and enables them to analyze a richer set of decision problems under uncertainty compared to what…

Vapour Pressure and Adiabatic Cooling from Champagne: Slow-Motion Visualization of Gas Thermodynamics

ERIC Educational Resources Information Center

Vollmer, Michael; Mollmann, Klaus-Peter

2012-01-01

The recent introduction of inexpensive high-speed cameras offers a new experimental approach to many simple but fast-occurring events in physics. In this paper, the authors present two simple demonstration experiments recorded with high-speed cameras in the fields of gas dynamics and thermal physics. The experiments feature vapour pressure effects…

A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation

ERIC Educational Resources Information Center

Wee, Loo Kang; Goh, Giam Hwee

2013-01-01

We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…

Special Relativity as a Simple Geometry Problem

ERIC Educational Resources Information Center

de Abreu, Rodrigo; Guerra, Vasco

2009-01-01

The null result of the Michelson-Morley experiment and the constancy of the one-way speed of light in the "rest system" are used to formulate a simple problem, to be solved by elementary geometry techniques using a pair of compasses and non-graduated rulers. The solution consists of a drawing allowing a direct visualization of all the fundamental…

The relationship of learning motivation, achievement and satisfaction for nurses learning simple excel VBA information systems programming.

PubMed

Lee, Ying Li; Chien, Tsai Feng; Kuo, Ming Chuan; Chang, Polun

2014-01-01

This study aims to understand the relationship between participating nurses' motivation, achievement and satisfaction before and after they learned to program in Excel Visual Basic for Applications (Excel VBA). We held a workshop to train nurses in developing simple Excel VBA information systems to support their clinical or administrative practices. Before and after the workshop, the participants were evaluated on their knowledge of Excel VBA, and a questionnaire was given to survey their learning motivation and satisfaction. Statistics softwares Winsteps and SPSS were used for data analysis. Results show that the participants are more knowledgeable about VBA as well as more motivated in learning VBA after the workshop. Participants were highly satisfied with the overall arrangement of the workshop and instructors, but didn't have enough confidence in promoting the application of Excel VBA themselves. In addition, we were unable to predict the participants' achievement by their demographic characteristics or pre-test motivation level.

Utility of a simple lighting device to improve chest compressions learning.

PubMed

González-Calvete, L; Barcala-Furelos, R; Moure-González, J D; Abelairas-Gómez, C; Rodríguez-Núñez, A

2017-11-01

The recommendations on cardiopulmonary resuscitation (CPR) emphasize the quality of the manoeuvres, especially chest compressions (CC). Audiovisual feedback devices could improve the quality of the CC during CPR. The aim of this study was to evaluate the usefulness of a simple lighting device as a visual aid during CPR on a mannequin. Twenty-two paediatricians who attended an accredited paediatric CPR course performed, in random order, 2min of CPR on a mannequin without and with the help of a simple lighting device, which flashes at a frequency of 100 cycles per minute. The following CC variables were analyzed using a validated compression quality meter (CPRmeter ® ): depth, decompression, rate, CPR time and percentage of compressions. With the lighting device, participants increased average quality (60.23±54.50 vs. 79.24±9.80%; P=.005), percentage in target depth (48.86±42.67 vs. 72.95±20.25%; P=.036) and rate (35.82±37.54 vs. 67.09±31.95%; P=.024). A simple light device that flashes at the recommended frequency improves the quality of CC performed by paediatric residents on a mannequin. The usefulness of this CPR aid system should be assessed in real patients. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Computational model for perception of objects and motions.

PubMed

Yang, WenLu; Zhang, LiQing; Ma, LiBo

2008-06-01

Perception of objects and motions in the visual scene is one of the basic problems in the visual system. There exist 'What' and 'Where' pathways in the superior visual cortex, starting from the simple cells in the primary visual cortex. The former is able to perceive objects such as forms, color, and texture, and the latter perceives 'where', for example, velocity and direction of spatial movement of objects. This paper explores brain-like computational architectures of visual information processing. We propose a visual perceptual model and computational mechanism for training the perceptual model. The computational model is a three-layer network. The first layer is the input layer which is used to receive the stimuli from natural environments. The second layer is designed for representing the internal neural information. The connections between the first layer and the second layer, called the receptive fields of neurons, are self-adaptively learned based on principle of sparse neural representation. To this end, we introduce Kullback-Leibler divergence as the measure of independence between neural responses and derive the learning algorithm based on minimizing the cost function. The proposed algorithm is applied to train the basis functions, namely receptive fields, which are localized, oriented, and bandpassed. The resultant receptive fields of neurons in the second layer have the characteristics resembling that of simple cells in the primary visual cortex. Based on these basis functions, we further construct the third layer for perception of what and where in the superior visual cortex. The proposed model is able to perceive objects and their motions with a high accuracy and strong robustness against additive noise. Computer simulation results in the final section show the feasibility of the proposed perceptual model and high efficiency of the learning algorithm.

Rehabilitation Approaches in Macular Degeneration Patients

PubMed Central

Maniglia, Marcello; Cottereau, Benoit R.; Soler, Vincent; Trotter, Yves

2016-01-01

Age related macular degeneration (AMD) is a visual disease that affects elderly population. It entails a progressive loss of central vision whose consequences are dramatic for the patient’s quality of life. Current rehabilitation programs are restricted to technical aids based on visual devices. They only temporarily improve specific visual functions such as reading skills. Considering the rapid increase of the aging population worldwide, it is crucial to intensify clinical research on AMD in order to develop simple and efficient methods that improve the patient’s visual performances in many different contexts. One very promising approach to face this challenge is based on perceptual learning (PL). Through intensive practice, PL can induce neural plasticity in sensory cortices and result in long-lasting enhancements for various perceptual tasks in both normal and visually impaired populations. A growing number of studies showed how appropriate PL protocols improve visual functions in visual disorders, namely amblyopia, presbyopia or myopia. In order to successfully apply these approaches to more severe conditions such as AMD, numerous challenges have to be overcome. Indeed, the overall elderly age of patients and the reduced cortical surface that is devoted to peripheral vision potentially limit neural plasticity in this population. In addition, ocular fixation becomes much less stable because patients have to rely on peripheral fixation spots outside the scotoma whose size keeps on evolving. The aim of this review article is to discuss the recent literature on this topic and to offer a unified approach for developing new rehabilitation programs of AMD using PL. We argue that with an appropriate experimental and training protocol that is adapted to each patient needs, PL can offer fascinating opportunities for the development of simple, non-expensive rehabilitation approaches a large spectrum of visual functions in AMD patients. PMID:28082876

Adapting to the 30-degree visual perspective by emulating the angled laparoscope: a simple and low-cost solution for basic surgical training.

PubMed

Daniel, Lorias Espinoza; Tapia, Fernando Montes; Arturo, Minor Martínez; Ricardo, Ordorica Flores

2014-12-01

The ability to handle and adapt to the visual perspectives generated by angled laparoscopes is crucial for skilled laparoscopic surgery. However, the control of the visual work space depends on the ability of the operator of the camera, who is often not the most experienced member of the surgical team. Here, we present a simple, low-cost option for surgical training that challenges the learner with static and dynamic visual perspectives at 30 degrees using a system that emulates the angled laparoscope. A system was developed using a low-cost camera and readily available materials to emulate the angled laparoscope. Nine participants undertook 3 tasks to test spatial adaptation to the static and dynamic visual perspectives at 30 degrees. Completing each task to a predefined satisfactory level ensured precision of execution of the tasks. Associated metrics (time and error rate) were recorded, and the performance of participants were determined. A total of 450 repetitions were performed by 9 residents at various stages of training. All the tasks were performed with a visual perspective of 30 degrees using the system. Junior residents were more proficient than senior residents. This system is a viable and low-cost alternative for developing the basic psychomotor skills necessary for the handling and adaptation to visual perspectives of 30 degrees, without depending on a laparoscopic tower, in junior residents. More advanced skills may then be acquired by other means, such as in the operating theater or through clinical experience.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendoza-Moctezuma, A. I.; Aguilar, J. Garcia; Garcia-Garduno, O. A.

Interventional cardiology procedures are an effective alternative for the reestablishment of correct sanguineous circulation in the heart. However, this kind of procedures exposes to the patients to a relatively high radiation doses. Usually, the surface peak skin dose is evaluated using a visual scale with a comparator strip, nevertheless, even if the comparator strip provides a simple and quick method for estimating the dose it has an uncertainty of {+-}25%. For this reason, a better evaluation method is needed. The objective of our project is to determine the surface peak skin dose of interventional cardiology procedures using GafChromic XR-RV2 filmmore » together with a commercial flatbed scanner in reflection mode. Here we report a protocol to handle GafChromic XR-RV2 film using a commercial flat bed scanner in reflection mode aiming at an uncertainty of {+-}3%.« less

20 CFR 416.985 - How we evaluate other visual impairments.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false How we evaluate other visual impairments. 416... evaluate other visual impairments. If you are not blind as defined in the law, we will evaluate a visual impairment the same as we evaluate other impairments in determining disability. Although you will not qualify...

The coupling of cerebral blood flow and oxygen metabolism with brain activation is similar for simple and complex stimuli in human primary visual cortex.

PubMed

Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

2015-01-01

Quantitative functional MRI (fMRI) experiments to measure blood flow and oxygen metabolism coupling in the brain typically rely on simple repetitive stimuli. Here we compared such stimuli with a more naturalistic stimulus. Previous work on the primary visual cortex showed that direct attentional modulation evokes a blood flow (CBF) response with a relatively large oxygen metabolism (CMRO2) response in comparison to an unattended stimulus, which evokes a much smaller metabolic response relative to the flow response. We hypothesized that a similar effect would be associated with a more engaging stimulus, and tested this by measuring the primary human visual cortex response to two contrast levels of a radial flickering checkerboard in comparison to the response to free viewing of brief movie clips. We did not find a significant difference in the blood flow-metabolism coupling (n=%ΔCBF/%ΔCMRO2) between the movie stimulus and the flickering checkerboards employing two different analysis methods: a standard analysis using the Davis model and a new analysis using a heuristic model dependent only on measured quantities. This finding suggests that in the primary visual cortex a naturalistic stimulus (in comparison to a simple repetitive stimulus) is either not sufficient to provoke a change in flow-metabolism coupling by attentional modulation as hypothesized, that the experimental design disrupted the cognitive processes underlying the response to a more natural stimulus, or that the technique used is not sensitive enough to detect a small difference. Copyright © 2014 Elsevier Inc. All rights reserved.

Development of a test for recording both visual and auditory reaction times, potentially useful for future studies in patients on opioids therapy

PubMed Central

Miceli, Luca; Bednarova, Rym; Rizzardo, Alessandro; Samogin, Valentina; Della Rocca, Giorgio

2015-01-01

Objective Italian Road Law limits driving while undergoing treatment with certain kinds of medication. Here, we report the results of a test, run as a smartphone application (app), assessing auditory and visual reflexes in a sample of 300 drivers. The scope of the test is to provide both the police force and medication-taking drivers with a tool that can evaluate the individual’s capacity to drive safely. Methods The test is run as an app for Apple iOS and Android mobile operating systems and facilitates four different reaction times to be assessed: simple visual and auditory reaction times and complex visual and auditory reaction times. Reference deciles were created for the test results obtained from a sample of 300 Italian subjects. Results lying within the first three deciles were considered as incompatible with safe driving capabilities. Results Performance is both age-related (r>0.5) and sex-related (female reaction times were significantly slower than those recorded for male subjects, P<0.05). Only 21% of the subjects were able to perform all four tests correctly. Conclusion We developed and fine-tuned a test called Safedrive that measures visual and auditory reaction times through a smartphone mobile device; the scope of the test is two-fold: to provide a clinical tool for the assessment of the driving capacity of individuals taking pain relief medication; to promote the sense of social responsibility in drivers who are on medication and provide these individuals with a means of testing their own capacity to drive safely. PMID:25709406

Sonification and haptic feedback in addition to visual feedback enhances complex motor task learning.

PubMed

Sigrist, Roland; Rauter, Georg; Marchal-Crespo, Laura; Riener, Robert; Wolf, Peter

2015-03-01

Concurrent augmented feedback has been shown to be less effective for learning simple motor tasks than for complex tasks. However, as mostly artificial tasks have been investigated, transfer of results to tasks in sports and rehabilitation remains unknown. Therefore, in this study, the effect of different concurrent feedback was evaluated in trunk-arm rowing. It was then investigated whether multimodal audiovisual and visuohaptic feedback are more effective for learning than visual feedback only. Naïve subjects (N = 24) trained in three groups on a highly realistic virtual reality-based rowing simulator. In the visual feedback group, the subject's oar was superimposed to the target oar, which continuously became more transparent when the deviation between the oars decreased. Moreover, a trace of the subject's trajectory emerged if deviations exceeded a threshold. The audiovisual feedback group trained with oar movement sonification in addition to visual feedback to facilitate learning of the velocity profile. In the visuohaptic group, the oar movement was inhibited by path deviation-dependent braking forces to enhance learning of spatial aspects. All groups significantly decreased the spatial error (tendency in visual group) and velocity error from baseline to the retention tests. Audiovisual feedback fostered learning of the velocity profile significantly more than visuohaptic feedback. The study revealed that well-designed concurrent feedback fosters complex task learning, especially if the advantages of different modalities are exploited. Further studies should analyze the impact of within-feedback design parameters and the transferability of the results to other tasks in sports and rehabilitation.

Development of a test for recording both visual and auditory reaction times, potentially useful for future studies in patients on opioids therapy.

PubMed

Miceli, Luca; Bednarova, Rym; Rizzardo, Alessandro; Samogin, Valentina; Della Rocca, Giorgio

2015-01-01

Italian Road Law limits driving while undergoing treatment with certain kinds of medication. Here, we report the results of a test, run as a smartphone application (app), assessing auditory and visual reflexes in a sample of 300 drivers. The scope of the test is to provide both the police force and medication-taking drivers with a tool that can evaluate the individual's capacity to drive safely. The test is run as an app for Apple iOS and Android mobile operating systems and facilitates four different reaction times to be assessed: simple visual and auditory reaction times and complex visual and auditory reaction times. Reference deciles were created for the test results obtained from a sample of 300 Italian subjects. Results lying within the first three deciles were considered as incompatible with safe driving capabilities. Performance is both age-related (r>0.5) and sex-related (female reaction times were significantly slower than those recorded for male subjects, P<0.05). Only 21% of the subjects were able to perform all four tests correctly. We developed and fine-tuned a test called Safedrive that measures visual and auditory reaction times through a smartphone mobile device; the scope of the test is two-fold: to provide a clinical tool for the assessment of the driving capacity of individuals taking pain relief medication; to promote the sense of social responsibility in drivers who are on medication and provide these individuals with a means of testing their own capacity to drive safely.

A Probabilistic Clustering Theory of the Organization of Visual Short-Term Memory

ERIC Educational Resources Information Center

Orhan, A. Emin; Jacobs, Robert A.

2013-01-01

Experimental evidence suggests that the content of a memory for even a simple display encoded in visual short-term memory (VSTM) can be very complex. VSTM uses organizational processes that make the representation of an item dependent on the feature values of all displayed items as well as on these items' representations. Here, we develop a…

Brief Report: Effect of Spatial Complexity on Visual Short-Term Memory and Self-Reported Autistic-Like Traits in Typically Developed Individuals

ERIC Educational Resources Information Center

Takahashi, Junichi; Gyoba, Jiro; Yamawaki, Nozomi

2013-01-01

This report examines effects of the spatial complexity of configurations on visual short-term memory (VSTM) capacity for individuals from the general population differing on autism-spectrum quotient (AQ) scores. During each trial, nine-line segments with various orientations were arrayed in simple or complex configurations and presented in both…

The Relationship between Visual Analysis and Five Statistical Analyses in a Simple AB Single-Case Research Design

ERIC Educational Resources Information Center

Brossart, Daniel F.; Parker, Richard I.; Olson, Elizabeth A.; Mahadevan, Lakshmi

2006-01-01

This study explored some practical issues for single-case researchers who rely on visual analysis of graphed data, but who also may consider supplemental use of promising statistical analysis techniques. The study sought to answer three major questions: (a) What is a typical range of effect sizes from these analytic techniques for data from…

Updating Target Location at the End of an Orienting Saccade Affects the Characteristics of Simple Point-to-Point Movements

ERIC Educational Resources Information Center

Desmurget, Michel; Turner, Robert S.; Prablanc, Claude; Russo, Gary S.; Alexander, Garret E.; Grafton, Scott T.

2005-01-01

Six results are reported. (a) Reaching accuracy increases when visual capture of the target is allowed (e.g., target on vs. target off at saccade onset). (b) Whatever the visual condition, trajectories diverge only after peak acceleration, suggesting that accuracy is improved through feedback mechanisms. (c) Feedback corrections are smoothly…

Coastal Surveillance Baseline Model Development

DTIC Science & Technology

2015-02-27

In the current STK model, a set of areas was defined for two reasons: To provide visual assistance during ship and aircraft route planning; and To...RF), electro-optic (EO), infrared (IR), and visual Partially Met The free version of STK can only generate simple generic sensors RQ-04 The model...25 APPENDIX A PLATFORM OBJECT ROUTE PLANNING PROCEDURE ............. A-1 APPENDIX B STK INSTALLATION

Boundaries in Visualizing Mathematical Behaviour

ERIC Educational Resources Information Center

Hare, Andrew Francis

2013-01-01

It is surprising to students to learn that a natural combination of simple functions, the function sin(1/x), exhibits behaviour that is a great challenge to visualize. When x is large the function is relatively easy to draw; as x gets smaller the function begins to behave in an increasingly wild manner. The sin(1/x) function can serve as one of…

The Textalk, A Uniquely Simple, Versatile Type of Audio-Visual Module: How to Prepare and Use It.

ERIC Educational Resources Information Center

Thomas, D. Des S.; Habowsky, J. E. J.

Textbooks emphasizing visual elements in exposition can be enriched using crisp, concise, audio-taped commentaries to focus attention on essential points in each illustration. These text aids, packaged in the convenient form of cassettes (usually one per chapter), have a number of obvious advantages: (1) any teacher can prepare them; (2) they are…

Teachers' Methodologies and Sources of Information on HIV/AIDS for Students with Visual Impairments in Selected Residential and Integrated Schools in Ghana

ERIC Educational Resources Information Center

Hayford, Samuel K.; Ocansey, Frederick

2017-01-01

This study reports part of a national survey on sources of information, education and communication materials on HIV/AIDS available to students with visual impairments in residential, segregated, and integrated schools in Ghana. A multi-staged stratified random sampling procedure and a purposive and simple random sampling approach, where…

The Quark Puzzle: A Novel Approach to Visualizing the Color Symmetries of Quarks

ERIC Educational Resources Information Center

Gettrust, Eric

2010-01-01

This paper describes a simple hands-on and visual-method designed to introduce physics students of many age groups to the topic of quarks and their role in forming composite particles (baryons and mesons). A set of puzzle pieces representing individual quarks that fit together in ways consistent with known restrictions of flavor, color, and charge…

There May Be More to Reaching than Meets the Eye: Re-Thinking Optic Ataxia

ERIC Educational Resources Information Center

Jackson, Stephen R.; Newport, Roger; Husain, Masud; Fowlie, Jane E.; O'Donoghue, Michael; Bajaj, Nin

2009-01-01

Optic ataxia (OA) is generally thought of as a disorder of visually guided reaching movements that cannot be explained by any simple deficit in visual or motor processing. In this paper we offer a new perspective on optic ataxia; we argue that the popular characterisation of this disorder is misleading and is unrepresentative of the pattern of…

[Meta-analysis of clinical randomized controlled trials comparing refractive with diffractive multifocal intraocular lenses in cataract surgery].

PubMed

Shao, Dewang; He, Shouzhi

2014-02-01

To systematic review the effectiveness of refractive multifocal intraocular lens (MIOL) versus diffractive MIOL in the treatment of cataract. Randomized controlled trials comparing refractive MIOL with diffractive MIOL were identified by searching PubMed (1966 to May, 2013), EMbase (1980 to May, 2013), Medline (1966 to May, 2013), and The Cochrane Library (Issue 1, 2013). We also hand-searched related journals. All the searches were restricted in English or Chinese. Methodological quality of randomized controlled trials (RCT) was evaluated by simple evaluate method that recommended by the Cochrane Collaboration. Data extracted by two reviewers with designed extraction form. RevMan software (release 5.2) was used for data management and analysis. A total of 11 trials (1460 eyes) were included for systematic review. Subgroup analyses were used according to different model comparison of MIOL. The results showed a significant difference in the mean of the uncorrected distance visual acuity (UCDVA) and the uncorrected intermediate visual acuity (UCIVA) in the refractive MIOL group with WMD -0.04, 95%CI -0.06 to -0.03 (P < 0.01) and WMD -0.05, 95%CI -0.09 to -0.02 (P = 0.001). It showed a significantly difference in the mean of the uncorrected near visual acuity (UCNVA), complete spectacle independent rate, halo rate and glare rate in the diffractive MIOL group with WMD 0.11, 95%CI 0.08 to 0.15 (P < 0.01), WMD 2.98, 95%CI 2.17 to 4.09 (P < 0.01), WMD 1.52, 95%CI 1.14 to 2.04 (P = 0.004) and WMD 1.27, 95%CI 1.07 to 1.50 (P = 0.005). There was no significant difference between the two groups in the mean of the best corrected distance visual acuity (BCDVA), the best distance corrected intermediate visual acuity (BDCIVA), the best distance corrected near visual acuity (BDCNVA) and the best corrected near visual acuity (BCNVA) with WMD -0.01, 95%CI -0.03 to 0.01 (P = 0.45), WMD -0.06, 95%CI -0.15 to 0.03 (P = 0.18), WMD 0.08, 95%CI -0.01 to 0.17 (P = 0.09) and WMD -0.02, 95%CI -0.26 to 0.23 (P = 0.88). Patients implanted with refractive MIOL show better uncorrected distance and intermediate visual acuity; patients implanted with diffractive MIOL show better uncorrected near visual acuity with less likely to appear light halo, glare and other visual adverse reactions. As for spectacles correction cases, patients implanted with diffractive or refractive MIOL have considerable performances in the far, middle, near visual acuity.

Cultural differences in attention: Eye movement evidence from a comparative visual search task.

PubMed

Alotaibi, Albandri; Underwood, Geoffrey; Smith, Alastair D

2017-10-01

Individual differences in visual attention have been linked to thinking style: analytic thinking (common in individualistic cultures) is thought to promote attention to detail and focus on the most important part of a scene, whereas holistic thinking (common in collectivist cultures) promotes attention to the global structure of a scene and the relationship between its parts. However, this theory is primarily based on relatively simple judgement tasks. We compared groups from Great Britain (an individualist culture) and Saudi Arabia (a collectivist culture) on a more complex comparative visual search task, using simple natural scenes. A higher overall number of fixations for Saudi participants, along with longer search times, indicated less efficient search behaviour than British participants. Furthermore, intra-group comparisons of scan-path for Saudi participants revealed less similarity than within the British group. Together, these findings suggest that there is a positive relationship between an analytic cognitive style and controlled attention. Copyright © 2017 Elsevier Inc. All rights reserved.

Simple device for the direct visualization of oral-cavity tissue fluorescence

NASA Astrophysics Data System (ADS)

Lane, Pierre M.; Gilhuly, Terence; Whitehead, Peter D.; Zeng, Haishan; Poh, Catherine; Ng, Samson; Williams, Michelle; Zhang, Lewei; Rosin, Miriam; MacAulay, Calum E.

2006-03-01

Early identification of high-risk disease could greatly reduce both mortality and morbidity due to oral cancer. We describe a simple handheld device that facilitates the direct visualization of oral-cavity fluorescence for the detection of high-risk precancerous and early cancerous lesions. Blue excitation light (400 to 460 nm) is employed to excite green-red fluorescence from fluorophores in the oral tissues. Tissue fluorescence is viewed directly along an optical axis collinear with the axis of excitation to reduce inter- and intraoperator variability. This robust, field-of-view device enables the direct visualization of fluorescence in the context of surrounding normal tissue. Results from a pilot study of 44 patients are presented. Using histology as the gold standard, the device achieves a sensitivity of 98% and specificity of 100% when discriminating normal mucosa from severe dysplasia/carcinoma in situ (CIS) or invasive carcinoma. We envisage this device as a suitable adjunct for oral cancer screening, biopsy guidance, and margin delineation.

The Emergence of Contrast-Invariant Orientation Tuning in Simple Cells of Cat Visual Cortex

PubMed Central

Finn, Ian M.; Priebe, Nicholas J.; Ferster, David

2007-01-01

Simple cells in primary visual cortex exhibit contrast-invariant orientation tuning, in seeming contradiction to feed-forward models relying on lateral geniculate nucleus (LGN) input alone. Contrast invariance has therefore been thought to depend on the presence of intracortical lateral inhibition. In vivo intracellular recordings instead suggest that contrast invariance can be explained by three properties of the excitatory pathway. 1) Depolarizations evoked by orthogonal stimuli are determined by the amount of excitation a cell receives from the LGN, relative to the excitation it receives from other cortical cells. 2) Depolarizations evoked by preferred stimuli saturate at lower contrasts than the spike output of LGN relay cells. 3) Visual stimuli evoke contrast-dependent changes in trial-to-trial variability, which lead to contrast-dependent changes in the relationship between membrane potential and spike rate. Thus, high-contrast, orthogonally-oriented stimuli that evoke significant depolarizations evoke few spikes. Together these mechanisms, without lateral inhibition, can account for contrast-invariant stimulus selectivity. PMID:17408583

Finding a face in the crowd: testing the anger superiority effect in Asperger Syndrome.

PubMed

Ashwin, Chris; Wheelwright, Sally; Baron-Cohen, Simon

2006-06-01

Social threat captures attention and is processed rapidly and efficiently, with many lines of research showing involvement of the amygdala. Visual search paradigms looking at social threat have shown angry faces 'pop-out' in a crowd, compared to happy faces. Autism and Asperger Syndrome (AS) are neurodevelopmental conditions characterised by social deficits, abnormal face processing, and amygdala dysfunction. We tested adults with high-functioning autism (HFA) and AS using a facial visual search paradigm with schematic neutral and emotional faces. We found, contrary to predictions, that people with HFA/AS performed similarly to controls in many conditions. However, the effect was reduced in the HFA/AS group when using widely varying crowd sizes and when faces were inverted, suggesting a difference in face-processing style may be evident even with simple schematic faces. We conclude there are intact threat detection mechanisms in AS, under simple and predictable conditions, but that like other face-perception tasks, the visual search of threat faces task reveals atypical face-processing in HFA/AS.

Viewing strategies for simple and chimeric faces: an investigation of perceptual bias in normals and schizophrenic patients using visual scan paths.

PubMed

Phillips, M L; David, A S

1997-11-01

Left hemi-face (LHF) perceptual bias of chimeric faces in normal right-handers is well-documented. We investigated mechanisms underlying this by measuring visual scan paths in right-handed normal controls (n = 9) and schizophrenics (n = 8) for simple, full-face photographs and schematic, happy-sad chimeric faces over 5 s. Normals viewed the left side/ LHF first, more so than the right of all stimuli. Schizophrenics viewed the LHF first more than the right of stimuli for which there was a LHF choice of predominant affect. Neither group demonstrated an overall LHF perceptual bias for the chimeric stimuli. Readjustment of the initial LHF bias in controls was probably a result of increased attention to stimulus detail with scanning, whereas the schizophrenics demonstrated difficulty in redirection of the initial focus of attention. The study highlights the role of visual scan paths as a marker of normal and abnormal attentional processes. Copyright 1997 Academic Press.

Synaptic physiology of the flow of information in the cat's visual cortex in vivo

PubMed Central

Hirsch, Judith A; Martinez, Luis M; Alonso, José-Manuel; Desai, Komal; Pillai, Cinthi; Pierre, Carhine

2002-01-01

Each stage of the striate cortical circuit extracts novel information about the visual environment. We asked if this analytic process reflected laminar variations in synaptic physiology by making whole-cell recording with dye-filled electrodes from the cat's visual cortex and thalamus; the stimuli were flashed spots. Thalamic afferents terminate in layer 4, which contains two types of cell, simple and complex, distinguished by the spatial structure of the receptive field. Previously, we had found that the postsynaptic and spike responses of simple cells reliably followed the time course of flash-evoked thalamic activity. Here we report that complex cells in layer 4 (or cells intermediate between simple and complex) similarly reprised thalamic activity (response/trial, 99 ± 1.9 %; response duration 159 ± 57 ms; latency 25 ± 4 ms; average ± standard deviation; n = 7). Thus, all cells in layer 4 share a common synaptic physiology that allows secure integration of thalamic input. By contrast, at the second cortical stage (layer 2+3), where layer 4 directs its output, postsynaptic responses did not track simple patterns of antecedent activity. Typical responses to the static stimulus were intermittent and brief (response/trial, 31 ± 40 %; response duration 72 ± 60 ms, latency 39 ± 7 ms; n = 11). Only richer stimuli like those including motion evoked reliable responses. All told, the second level of cortical processing differs markedly from the first. At that later stage, ascending information seems strongly gated by connections between cortical neurons. Inputs must be combined in newly specified patterns to influence intracortical stages of processing. PMID:11927691

The attentional drift-diffusion model extends to simple purchasing decisions.

PubMed

Krajbich, Ian; Lu, Dingchao; Camerer, Colin; Rangel, Antonio

2012-01-01

How do we make simple purchasing decisions (e.g., whether or not to buy a product at a given price)? Previous work has shown that the attentional drift-diffusion model (aDDM) can provide accurate quantitative descriptions of the psychometric data for binary and trinary value-based choices, and of how the choice process is guided by visual attention. Here we extend the aDDM to the case of purchasing decisions, and test it using an eye-tracking experiment. We find that the model also provides a reasonably accurate quantitative description of the relationship between choice, reaction time, and visual fixations using parameters that are very similar to those that best fit the previous data. The only critical difference is that the choice biases induced by the fixations are about half as big in purchasing decisions as in binary choices. This suggests that a similar computational process is used to make binary choices, trinary choices, and simple purchasing decisions.

A smart sensor architecture based on emergent computation in an array of outer-totalistic cells

NASA Astrophysics Data System (ADS)

Dogaru, Radu; Dogaru, Ioana; Glesner, Manfred

2005-06-01

A novel smart-sensor architecture is proposed, capable to segment and recognize characters in a monochrome image. It is capable to provide a list of ASCII codes representing the recognized characters from the monochrome visual field. It can operate as a blind's aid or for industrial applications. A bio-inspired cellular model with simple linear neurons was found the best to perform the nontrivial task of cropping isolated compact objects such as handwritten digits or characters. By attaching a simple outer-totalistic cell to each pixel sensor, emergent computation in the resulting cellular automata lattice provides a straightforward and compact solution to the otherwise computationally intensive problem of character segmentation. A simple and robust recognition algorithm is built in a compact sequential controller accessing the array of cells so that the integrated device can provide directly a list of codes of the recognized characters. Preliminary simulation tests indicate good performance and robustness to various distortions of the visual field.

The Attentional Drift-Diffusion Model Extends to Simple Purchasing Decisions

PubMed Central

Krajbich, Ian; Lu, Dingchao; Camerer, Colin; Rangel, Antonio

2012-01-01

How do we make simple purchasing decisions (e.g., whether or not to buy a product at a given price)? Previous work has shown that the attentional drift-diffusion model (aDDM) can provide accurate quantitative descriptions of the psychometric data for binary and trinary value-based choices, and of how the choice process is guided by visual attention. Here we extend the aDDM to the case of purchasing decisions, and test it using an eye-tracking experiment. We find that the model also provides a reasonably accurate quantitative description of the relationship between choice, reaction time, and visual fixations using parameters that are very similar to those that best fit the previous data. The only critical difference is that the choice biases induced by the fixations are about half as big in purchasing decisions as in binary choices. This suggests that a similar computational process is used to make binary choices, trinary choices, and simple purchasing decisions. PMID:22707945

A simple technique for measurement of pressure in the tympanitic rumen of cattle.

PubMed

Turner, C B; Whyte, T D

1978-05-13

The construction and method of use of a simple device for the non-invasive measurement of intra-rumenal pressure is outlined. Results obtained from calves suffering from increased intra-rumenal pressure (bloat) are shown. The method is capable of quantifying pressures involved in bloat and could be used to augment the visual assessment of bloat scoring.

A Simple Experiment for Visualizing Diffusion

ERIC Educational Resources Information Center

Helseth, L. E.

2011-01-01

We propose a simple and fascinating experiment for studying diffusion in gels using a pH-sensitive dye. By doping agar with methyl red, we obtain a gel which rapidly reacts to changes in pH by changing its absorption spectrum. The pH gradients can be followed using a digital camera, and we demonstrate here that the pH-sensitive colour changes can…

A geostationary Earth orbit satellite model using Easy Java Simulation

NASA Astrophysics Data System (ADS)

Wee, Loo Kang; Hwee Goh, Giam

2013-01-01

We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic 3D view and associated learning in the real world; (2) comparative visualization of permanent geostationary satellites; (3) examples of non-geostationary orbits of different rotation senses, periods and planes; and (4) an incorrect physics model for conceptual discourse. General feedback from the students has been relatively positive, and we hope teachers will find the computer model useful in their own classes.

The Zombie Plot: A Simple Graphic Method for Visualizing the Efficacy of a Diagnostic Test.

PubMed

Richardson, Michael L

2016-08-09

One of the most important jobs of a radiologist is to pick the most appropriate imaging test for a particular clinical situation. Making a proper selection sometimes requires statistical analysis. The objective of this article is to introduce a simple graphic technique, an ROC plot that has been divided into zones of mostly bad imaging efficacy (ZOMBIE, hereafter referred to as the "zombie plot"), that transforms information about imaging efficacy from the numeric domain into the visual domain. The numeric rationale for the use of zombie plots is given, as are several examples of the clinical use of these plots. Two online calculators are described that simplify the process of producing a zombie plot.

Hooke's Law and the Stiffness of a Plastic Spoon

NASA Astrophysics Data System (ADS)

Pestka, Kenneth A.; Warren, Cori

2012-11-01

The study of elastic properties of solids is essential to both physics and engineering. Finding simple, easy-to-visualize examples to demonstrate these concepts is often difficult. In a previous article written by one of us (KAPII), a simple method for determining Youngs modulus using marshmallows was given. In this article we will illustrate another method to explore elastic properties of everyday materials. This experiment uses a common plastic spoon exposed to a transverse force in order to determine the stiffness constant, yield point, and rupture point of the plastic spoon. In addition, much like the "Youngs Modulus of a Marshmallow" activity, this experiment visually demonstrates Hooke's law, is fun and easy to perform, and leaves a lasting impression on the students.

Executive and Perceptual Distraction in Visual Working Memory

PubMed Central

2017-01-01

The contents of visual working memory are likely to reflect the influence of both executive control resources and information present in the environment. We investigated whether executive attention is critical in the ability to exclude unwanted stimuli by introducing concurrent potentially distracting irrelevant items to a visual working memory paradigm, and manipulating executive load using simple or more demanding secondary verbal tasks. Across 7 experiments varying in presentation format, timing, stimulus set, and distractor number, we observed clear disruptive effects of executive load and visual distraction, but relatively minimal evidence supporting an interactive relationship between these factors. These findings are in line with recent evidence using delay-based interference, and suggest that different forms of attentional selection operate relatively independently in visual working memory. PMID:28414499

Multitask visual learning using genetic programming.

PubMed

Jaśkowski, Wojciech; Krawiec, Krzysztof; Wieloch, Bartosz

2008-01-01

We propose a multitask learning method of visual concepts within the genetic programming (GP) framework. Each GP individual is composed of several trees that process visual primitives derived from input images. Two trees solve two different visual tasks and are allowed to share knowledge with each other by commonly calling the remaining GP trees (subfunctions) included in the same individual. The performance of a particular tree is measured by its ability to reproduce the shapes contained in the training images. We apply this method to visual learning tasks of recognizing simple shapes and compare it to a reference method. The experimental verification demonstrates that such multitask learning often leads to performance improvements in one or both solved tasks, without extra computational effort.

Atypical Balance between Occipital and Fronto-Parietal Activation for Visual Shape Extraction in Dyslexia

PubMed Central

Zhang, Ying; Whitfield-Gabrieli, Susan; Christodoulou, Joanna A.; Gabrieli, John D. E.

2013-01-01

Reading requires the extraction of letter shapes from a complex background of text, and an impairment in visual shape extraction would cause difficulty in reading. To investigate the neural mechanisms of visual shape extraction in dyslexia, we used functional magnetic resonance imaging (fMRI) to examine brain activation while adults with or without dyslexia responded to the change of an arrow’s direction in a complex, relative to a simple, visual background. In comparison to adults with typical reading ability, adults with dyslexia exhibited opposite patterns of atypical activation: decreased activation in occipital visual areas associated with visual perception, and increased activation in frontal and parietal regions associated with visual attention. These findings indicate that dyslexia involves atypical brain organization for fundamental processes of visual shape extraction even when reading is not involved. Overengagement in higher-order association cortices, required to compensate for underengagment in lower-order visual cortices, may result in competition for top-down attentional resources helpful for fluent reading. PMID:23825653

Visual attention capacity: a review of TVA-based patient studies.

PubMed

Habekost, Thomas; Starrfelt, Randi

2009-02-01

Psychophysical studies have identified two distinct limitations of visual attention capacity: processing speed and apprehension span. Using a simple test, these cognitive factors can be analyzed by Bundesen's Theory of Visual Attention (TVA). The method has strong specificity and sensitivity, and measurements are highly reliable. As the method is theoretically founded, it also has high validity. TVA-based assessment has recently been used to investigate a broad range of neuropsychological and neurological conditions. We present the method, including the experimental paradigm and practical guidelines to patient testing, and review existing TVA-based patient studies organized by lesion anatomy. Lesions in three anatomical regions affect visual capacity: The parietal lobes, frontal cortex and basal ganglia, and extrastriate cortex. Visual capacity thus depends on large, bilaterally distributed anatomical networks that include several regions outside the visual system. The two visual capacity parameters are functionally separable, but seem to rely on largely overlapping brain areas.

Development of cortical orientation selectivity in the absence of visual experience with contour

PubMed Central

Hussain, Shaista; Weliky, Michael

2011-01-01

Visual cortical neurons are selective for the orientation of lines, and the full development of this selectivity requires natural visual experience after eye opening. Here we examined whether this selectivity develops without seeing lines and contours. Juvenile ferrets were reared in a dark room and visually trained by being shown a movie of flickering, sparse spots. We found that despite the lack of contour visual experience, the cortical neurons of these ferrets developed strong orientation selectivity and exhibited simple-cell receptive fields. This finding suggests that overt contour visual experience is unnecessary for the maturation of orientation selectivity and is inconsistent with the computational models that crucially require the visual inputs of lines and contours for the development of orientation selectivity. We propose that a correlation-based model supplemented with a constraint on synaptic strength dynamics is able to account for our experimental result. PMID:21753023

Phonological Concept Learning.

PubMed

Moreton, Elliott; Pater, Joe; Pertsova, Katya

2017-01-01

Linguistic and non-linguistic pattern learning have been studied separately, but we argue for a comparative approach. Analogous inductive problems arise in phonological and visual pattern learning. Evidence from three experiments shows that human learners can solve them in analogous ways, and that human performance in both cases can be captured by the same models. We test GMECCS (Gradual Maximum Entropy with a Conjunctive Constraint Schema), an implementation of the Configural Cue Model (Gluck & Bower, ) in a Maximum Entropy phonotactic-learning framework (Goldwater & Johnson, ; Hayes & Wilson, ) with a single free parameter, against the alternative hypothesis that learners seek featurally simple algebraic rules ("rule-seeking"). We study the full typology of patterns introduced by Shepard, Hovland, and Jenkins () ("SHJ"), instantiated as both phonotactic patterns and visual analogs, using unsupervised training. Unlike SHJ, Experiments 1 and 2 found that both phonotactic and visual patterns that depended on fewer features could be more difficult than those that depended on more features, as predicted by GMECCS but not by rule-seeking. GMECCS also correctly predicted performance differences between stimulus subclasses within each pattern. A third experiment tried supervised training (which can facilitate rule-seeking in visual learning) to elicit simple rule-seeking phonotactic learning, but cue-based behavior persisted. We conclude that similar cue-based cognitive processes are available for phonological and visual concept learning, and hence that studying either kind of learning can lead to significant insights about the other. Copyright © 2015 Cognitive Science Society, Inc.

Outcomes of photorefractive keratectomy in patients with atypical topography.

PubMed

Movahedan, Hossein; Namvar, Ehsan; Farvardin, Mohsen

2017-11-01

Photorefractive keratectomy (PRK) is at risk of serious complications such as corneal ectasia, which can reduce corrected distance visual acuity. The rate of complications of PRK is higher in patients with atypical topography. To determine the outcomes of photorefractive keratectomy in patients with atypical topography. This cross-sectional study was done in 2015 in Shiraz in Iran. We included 85 eyes in this study. The samples were selected using a simple random sampling method. All patients were under evaluation for uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction, corneal topography, central corneal thickness using pentacam, slit-lamp microscopy, and detailed fondus evaluation. The postoperative examination was done 1-7 years after surgery. Data were analyzed using IBM SPSS 21.0 version. To analyze the data, descriptive statistics (frequency, percentage, mean, and standard deviation), chi-square, and independent samples t-test were used. We studied 85 eyes. Among the patients, 23 (27.1%) were male and 62 (72.9%) were female. Mean age of the participants was 28.25±5.55 years. Mean postoperative refraction was - 0.37±0.55 diopters. Keratoconus or corneal ectasia was not reported in any patient in this study. There was no statistically significant difference between SI index before and after operation (p=0.736). Mean preoperative refraction was -3.84 ± 1.46 diopters in males and -4.20±1.96 diopters in females; thus there was not statistically significant difference (p = 0.435). PRK is a safe and efficient photorefractive surgery and is associated with low complication rate in patients with atypical topography.

Evaluation of the User Strategy on 2d and 3d City Maps Based on Novel Scanpath Comparison Method and Graph Visualization

NASA Astrophysics Data System (ADS)

Dolezalova, J.; Popelka, S.

2016-06-01

The paper is dealing with scanpath comparison of eye-tracking data recorded during case study focused on the evaluation of 2D and 3D city maps. The experiment contained screenshots from three map portals. Two types of maps were used - standard map and 3D visualization. Respondents' task was to find particular point symbol on the map as fast as possible. Scanpath comparison is one group of the eye-tracking data analyses methods used for revealing the strategy of the respondents. In cartographic studies, the most commonly used application for scanpath comparison is eyePatterns that output is hierarchical clustering and a tree graph representing the relationships between analysed sequences. During an analysis of the algorithm generating a tree graph, it was found that the outputs do not correspond to the reality. We proceeded to the creation of a new tool called ScanGraph. This tool uses visualization of cliques in simple graphs and is freely available at www.eyetracking.upol.cz/scangraph. Results of the study proved the functionality of the tool and its suitability for analyses of different strategies of map readers. Based on the results of the tool, similar scanpaths were selected, and groups of respondents with similar strategies were identified. With this knowledge, it is possible to analyse the relationship between belonging to the group with similar strategy and data gathered from the questionnaire (age, sex, cartographic knowledge, etc.) or type of stimuli (2D, 3D map).

Clues for minimal hepatic encephalopathy in children with noncirrhotic portal hypertension.

PubMed

D'Antiga, Lorenzo; Dacchille, Patrizia; Boniver, Clementina; Poledri, Sara; Schiff, Sami; Zancan, Lucia; Amodio, Piero

2014-12-01

In children with noncirrhotic extrahepatic portal vein obstruction (EHPVO), minimal hepatic encephalopathy (MHE) was reported in a few series, but neither is it routinely investigated nor does consensus about its diagnosis exist. In this prospective observational study we aimed at detecting the prevalence of MHE in children with EHPVO and providing a practical diagnostic protocol. A consecutive sample of 13 noncirrhotic children (age range 4-18 years) with EHPVO underwent a screening for MHE based on level of fasting ammonia, quantified electroencephalogram (EEG) evaluation, and a wide battery of 26 psychometric tests exploring learning ability, abstract reasoning, phonemic and semantic fluency, selective attention, executive functions, short-term verbal and visual memory, long-term verbal memory, and visuopractic ability. Five children had at least 2 altered psychometric tests. Selective attention, executive function, and short-term visual memory were the domains more frequently altered, and 4 tests were enough to detect 80% of these children. Fasting ammonia plasma level was increased in 6 children. EEG mean dominant frequency adjusted for age was associated with serum ammonia concentration (β = -0.44 ± 0.19, P < 0.05). As a whole, children with EHPVO showed trends for lower α (median 41% vs 49%) and higher θ power than controls (median 41% vs 49% and 29% vs 20%, respectively). MHE affects approximately 50% of children with EHPVO and, therefore, is worthwhile to be investigated. Three simple tools, serum ammonia, quantified EEG, and neuropsychological examination, focused on selective attention, executive function, and short-term visual memory can be used effectively in the evaluation of MHE in this setting.

Evaluation of Visualization Software

NASA Technical Reports Server (NTRS)

Globus, Al; Uselton, Sam

1995-01-01

Visualization software is widely used in scientific and engineering research. But computed visualizations can be very misleading, and the errors are easy to miss. We feel that the software producing the visualizations must be thoroughly evaluated and the evaluation process as well as the results must be made available. Testing and evaluation of visualization software is not a trivial problem. Several methods used in testing other software are helpful, but these methods are (apparently) often not used. When they are used, the description and results are generally not available to the end user. Additional evaluation methods specific to visualization must also be developed. We present several useful approaches to evaluation, ranging from numerical analysis of mathematical portions of algorithms to measurement of human performance while using visualization systems. Along with this brief survey, we present arguments for the importance of evaluations and discussions of appropriate use of some methods.

Toward an affordable and user-friendly visual motion capture system.

PubMed

Bonnet, V; Sylla, N; Cherubini, A; Gonzáles, A; Azevedo Coste, C; Fraisse, P; Venture, G

2014-01-01

The present study aims at designing and evaluating a low-cost, simple and portable system for arm joint angle estimation during grasping-like motions. The system is based on a single RGB-D camera and three customized markers. The automatically detected and tracked marker positions were used as inputs to an offline inverse kinematic process based on bio-mechanical constraints to reduce noise effect and handle marker occlusion. The method was validated on 4 subjects with different motions. The joint angles were estimated both with the proposed low-cost system and, a stereophotogrammetric system. Comparative analysis shows good accuracy with high correlation coefficient (r= 0.92) and low average RMS error (3.8 deg).

Simple and versatile heterodyne whole-field interferometer for phase optics characterization.

PubMed

Silva, D M; Barbosa, E A; Wetter, N U

2012-10-01

A wavefront sensor for thermally induced lens and passive lens characterization based on low-coherence digital speckle interferometry was developed and studied. By illuminating the optical setup with two slightly detuned red diode lasers, whole-field contour interference fringes were generated according to the resulting synthetic wavelength. For fringe pattern visualization the optical setup used the light transmitted through a ground glass plate as object beam. The performance of the sensor was investigated and its versatility was demonstrated by measuring the thermal lens induced in an Er-doped glass sample pumped by a 1.76-W diode laser emitting at 976 nm and by evaluating the wavefront distortion introduced by an ophthalmic progressive lens.

Filter methods to preserve local contrast and to avoid artifacts in gamut mapping

NASA Astrophysics Data System (ADS)

Meili, Marcel; Küpper, Dennis; Barańczuk, Zofia; Caluori, Ursina; Simon, Klaus

2010-01-01

Contrary to high dynamic range imaging, the preservation of details and the avoidance of artifacts is not explicitly considered in popular color management systems. An effective way to overcome these difficulties is image filtering. In this paper we investigate several image filter concepts for detail preservation as part of a practical gamut mapping strategy. In particular we define four concepts including various image filters and check their performance with a psycho-visual test. Additionally, we compare our performance evaluation to two image quality measures with emphasis on local contrast. Surprisingly, the most simple filter concept performs highly efficient and achieves an image quality which is comparable to the more established but slower methods.

Transport of a decay chain in homogenous porous media: analytical solutions.

PubMed

Bauer, P; Attinger, S; Kinzelbach, W

2001-06-01

With the aid of integral transforms, analytical solutions for the transport of a decay chain in homogenous porous media are derived. Unidirectional steady-state flow and radial steady-state flow in single and multiple porosity media are considered. At least in Laplace domain, all solutions can be written in closed analytical formulae. Partly, the solutions can also be inverted analytically. If not, analytical calculation of the steady-state concentration distributions, evaluation of temporal moments and numerical inversion are still possible. Formulae for several simple boundary conditions are given and visualized in this paper. The derived novel solutions are widely applicable and are very useful for the validation of numerical transport codes.

Visual cortex in dementia with Lewy bodies: magnetic resonance imaging study

PubMed Central

Taylor, John-Paul; Firbank, Michael J.; He, Jiabao; Barnett, Nicola; Pearce, Sarah; Livingstone, Anthea; Vuong, Quoc; McKeith, Ian G.; O’Brien, John T.

2012-01-01

Background Visual hallucinations and visuoperceptual deficits are common in dementia with Lewy bodies, suggesting that cortical visual function may be abnormal. Aims To investigate: (1) cortical visual function using functional magnetic resonance imaging (fMRI); and (2) the nature and severity of perfusion deficits in visual areas using arterial spin labelling (ASL)-MRI. Method In total, 17 participants with dementia with Lewy bodies (DLB group) and 19 similarly aged controls were presented with simple visual stimuli (checkerboard, moving dots, and objects) during fMRI and subsequently underwent ASL-MRI (DLB group n = 15, control group n = 19). Results Functional activations were evident in visual areas in both the DLB and control groups in response to checkerboard and objects stimuli but reduced visual area V5/MT (middle temporal) activation occurred in the DLB group in response to motion stimuli. Posterior cortical perfusion deficits occurred in the DLB group, particularly in higher visual areas. Conclusions Higher visual areas, particularly occipito-parietal, appear abnormal in dementia with Lewy bodies, while there is a preservation of function in lower visual areas (V1 and V2/3). PMID:22500014

Visuo-Haptic Mixed Reality with Unobstructed Tool-Hand Integration.

PubMed

Cosco, Francesco; Garre, Carlos; Bruno, Fabio; Muzzupappa, Maurizio; Otaduy, Miguel A

2013-01-01

Visuo-haptic mixed reality consists of adding to a real scene the ability to see and touch virtual objects. It requires the use of see-through display technology for visually mixing real and virtual objects, and haptic devices for adding haptic interaction with the virtual objects. Unfortunately, the use of commodity haptic devices poses obstruction and misalignment issues that complicate the correct integration of a virtual tool and the user's real hand in the mixed reality scene. In this work, we propose a novel mixed reality paradigm where it is possible to touch and see virtual objects in combination with a real scene, using commodity haptic devices, and with a visually consistent integration of the user's hand and the virtual tool. We discuss the visual obstruction and misalignment issues introduced by commodity haptic devices, and then propose a solution that relies on four simple technical steps: color-based segmentation of the hand, tracking-based segmentation of the haptic device, background repainting using image-based models, and misalignment-free compositing of the user's hand. We have developed a successful proof-of-concept implementation, where a user can touch virtual objects and interact with them in the context of a real scene, and we have evaluated the impact on user performance of obstruction and misalignment correction.

Hazards and accessibility: combining and visualizing threat and open infrastructure data for disaster management

NASA Astrophysics Data System (ADS)

Tost, Jordi; Ehmel, Fabian; Heidmann, Frank; Olen, Stephanie M.; Bookhagen, Bodo

2018-05-01

The assessment of natural hazards and risk has traditionally been built upon the estimation of threat maps, which are used to depict potential danger posed by a particular hazard throughout a given area. But when a hazard event strikes, infrastructure is a significant factor that can determine if the situation becomes a disaster. The vulnerability of the population in a region does not only depend on the area's local threat, but also on the geographical accessibility of the area. This makes threat maps by themselves insufficient for supporting real-time decision-making, especially for those tasks that involve the use of the road network, such as management of relief operations, aid distribution, or planning of evacuation routes, among others. To overcome this problem, this paper proposes a multidisciplinary approach divided in two parts. First, data fusion of satellite-based threat data and open infrastructure data from OpenStreetMap, introducing a threat-based routing service. Second, the visualization of this data through cartographic generalization and schematization. This emphasizes critical areas along roads in a simple way and allows users to visually evaluate the impact natural hazards may have on infrastructure. We develop and illustrate this methodology with a case study of landslide threat for an area in Colombia.

Face recognition increases during saccade preparation.

PubMed

Lin, Hai; Rizak, Joshua D; Ma, Yuan-ye; Yang, Shang-chuan; Chen, Lin; Hu, Xin-tian

2014-01-01

Face perception is integral to human perception system as it underlies social interactions. Saccadic eye movements are frequently made to bring interesting visual information, such as faces, onto the fovea for detailed processing. Just before eye movement onset, the processing of some basic features, such as the orientation, of an object improves at the saccade landing point. Interestingly, there is also evidence that indicates faces are processed in early visual processing stages similar to basic features. However, it is not known whether this early enhancement of processing includes face recognition. In this study, three experiments were performed to map the timing of face presentation to the beginning of the eye movement in order to evaluate pre-saccadic face recognition. Faces were found to be similarly processed as simple objects immediately prior to saccadic movements. Starting ∼ 120 ms before a saccade to a target face, independent of whether or not the face was surrounded by other faces, the face recognition gradually improved and the critical spacing of the crowding decreased as saccade onset was approaching. These results suggest that an upcoming saccade prepares the visual system for new information about faces at the saccade landing site and may reduce the background in a crowd to target the intended face. This indicates an important role of pre-saccadic eye movement signals in human face recognition.

A Methodology for Evaluating the Fidelity of Ground-Based Flight Simulators

NASA Technical Reports Server (NTRS)

Zeyada, Y.; Hess, R. A.

1999-01-01

An analytical and experimental investigation was undertaken to model the manner in which pilots perceive and utilize visual, proprioceptive, and vestibular cues in a ground-based flight simulator. The study was part of a larger research effort which has the creation of a methodology for determining flight simulator fidelity requirements as its ultimate goal. The study utilized a closed-loop feedback structure of the pilot/simulator system which included the pilot, the cockpit inceptor, the dynamics of the simulated vehicle and the motion system. With the exception of time delays which accrued in visual scene production in the simulator, visual scene effects were not included in this study. The NASA Ames Vertical Motion Simulator was used in a simple, single-degree of freedom rotorcraft bob-up/down maneuver. Pilot/vehicle analysis and fuzzy-inference identification were employed to study the changes in fidelity which occurred as the characteristics of the motion system were varied over five configurations i The data from three of the five pilots that participated in the experimental study were analyzed in the fuzzy inference identification. Results indicate that both the analytical pilot/vehicle analysis and the fuzzyinference identification can be used to reflect changes in simulator fidelity for the task examined.

A Methodology for Evaluating the Fidelity of Ground-Based Flight Simulators

NASA Technical Reports Server (NTRS)

Zeyada, Y.; Hess, R. A.

1999-01-01

An analytical and experimental investigation was undertaken to model the manner in which pilots perceive and utilize visual, proprioceptive, and vestibular cues in a ground-based flight simulator. The study was part of a larger research effort which has the creation of a methodology for determining flight simulator fidelity requirements as its ultimate goal. The study utilized a closed-loop feedback structure of the pilot/simulator system which included the pilot, the cockpit inceptor, the dynamics of the simulated vehicle and the motion system. With the exception of time delays which accrued in visual scene production in the simulator, visual scene effects were not included in this study. The NASA Ames Vertical Motion Simulator was used in a simple, single-degree of freedom rotorcraft bob-up/down maneuver. Pilot/vehicle analysis and fuzzy-inference identification were employed to study the changes in fidelity which occurred as the characteristics of the motion system were varied over five configurations. The data from three of the five pilots that participated in the experimental study were analyzed in the fuzzy-inference identification. Results indicate that both the analytical pilot/vehicle analysis and the fuzzy-inference identification can be used to reflect changes in simulator fidelity for the task examined.

Effects of refractive errors on visual evoked magnetic fields.

PubMed

Suzuki, Masaya; Nagae, Mizuki; Nagata, Yuko; Kumagai, Naoya; Inui, Koji; Kakigi, Ryusuke

2015-11-09

The latency and amplitude of visual evoked cortical responses are known to be affected by refractive states, suggesting that they may be used as an objective index of refractive errors. In order to establish an easy and reliable method for this purpose, we herein examined the effects of refractive errors on visual evoked magnetic fields (VEFs). Binocular VEFs following the presentation of a simple grating of 0.16 cd/m(2) in the lower visual field were recorded in 12 healthy volunteers and compared among four refractive states: 0D, +1D, +2D, and +4D, by using plus lenses. The low-luminance visual stimulus evoked a main MEG response at approximately 120 ms (M100) that reversed its polarity between the upper and lower visual field stimulations and originated from the occipital midline area. When refractive errors were induced by plus lenses, the latency of M100 increased, while its amplitude decreased with an increase in power of the lens. Differences from the control condition (+0D) were significant for all three lenses examined. The results of dipole analyses showed that evoked fields for the control (+0D) condition were explainable by one dipole in the primary visual cortex (V1), while other sources, presumably in V3 or V6, slightly contributed to shape M100 for the +2D or +4D condition. The present results showed that the latency and amplitude of M100 are both useful indicators for assessing refractive states. The contribution of neural sources other than V1 to M100 was modest under the 0D and +1D conditions. By considering the nature of the activity of M100 including its high sensitivity to a spatial frequency and lower visual field dominance, a simple low-luminance grating stimulus at an optimal spatial frequency in the lower visual field appears appropriate for obtaining data on high S/N ratios and reducing the load on subjects.

Visualizing deep neural network by alternately image blurring and deblurring.

PubMed

Wang, Feng; Liu, Haijun; Cheng, Jian

2018-01-01

Visualization from trained deep neural networks has drawn massive public attention in recent. One of the visualization approaches is to train images maximizing the activation of specific neurons. However, directly maximizing the activation would lead to unrecognizable images, which cannot provide any meaningful information. In this paper, we introduce a simple but effective technique to constrain the optimization route of the visualization. By adding two totally inverse transformations, image blurring and deblurring, to the optimization procedure, recognizable images can be created. Our algorithm is good at extracting the details in the images, which are usually filtered by previous methods in the visualizations. Extensive experiments on AlexNet, VGGNet and GoogLeNet illustrate that we can better understand the neural networks utilizing the knowledge obtained by the visualization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advanced Visualization and Interactive Display Rapid Innovation and Discovery Evaluation Research (VISRIDER) Program Task 6: Point Cloud Visualization Techniques for Desktop and Web Platforms

DTIC Science & Technology

2017-04-01

ADVANCED VISUALIZATION AND INTERACTIVE DISPLAY RAPID INNOVATION AND DISCOVERY EVALUATION RESEARCH (VISRIDER) PROGRAM TASK 6: POINT CLOUD...To) OCT 2013 – SEP 2014 4. TITLE AND SUBTITLE ADVANCED VISUALIZATION AND INTERACTIVE DISPLAY RAPID INNOVATION AND DISCOVERY EVALUATION RESEARCH...various point cloud visualization techniques for viewing large scale LiDAR datasets. Evaluate their potential use for thick client desktop platforms

Effects of Varied Enhancement Strategies (Chunking, Feedback, Gaming) in Complementing Animated Instruction in Facilitating Different Types of Learning Objectives

ERIC Educational Resources Information Center

Munyofu, Mine

2008-01-01

The purpose of this study was to examine the instructional effectiveness of different levels of chunking (simple visual/text and complex visual/text), different forms of feedback (item-by-item feedback, end-of-test feedback and no feedback), and use of instructional gaming (game and no game) in complementing animated programmed instruction on a…

Area 18 of the cat: the first step in processing visual movement information.

PubMed

Orban, G A

1977-01-01

In cats, responses of area 18 neurons to different moving patterns were measured. The influence of three movement parameters--direction, angular velocity, and amplitude of movement--were tested. The results indicate that in area 18 no ideal movement detector exists, but that simple and complex cells each perform complementary operations of primary visual areas, i.e. analysis and detection of movement.

Testing a Poisson Counter Model for Visual Identification of Briefly Presented, Mutually Confusable Single Stimuli in Pure Accuracy Tasks

ERIC Educational Resources Information Center

Kyllingsbaek, Soren; Markussen, Bo; Bundesen, Claus

2012-01-01

The authors propose and test a simple model of the time course of visual identification of briefly presented, mutually confusable single stimuli in pure accuracy tasks. The model implies that during stimulus analysis, tentative categorizations that stimulus i belongs to category j are made at a constant Poisson rate, v(i, j). The analysis is…

Comparison of six simple methods for extracting ribosomal and mitochondrial DNA from Toxocara and Toxascaris nematodes.

PubMed

Mikaeili, F; Kia, E B; Sharbatkhori, M; Sharifdini, M; Jalalizand, N; Heidari, Z; Zarei, Z; Stensvold, C R; Mirhendi, H

2013-06-01

Six simple methods for extraction of ribosomal and mitochondrial DNA from Toxocara canis, Toxocara cati and Toxascaris leonina were compared by evaluating the presence, appearance and intensity of PCR products visualized on agarose gels and amplified from DNA extracted by each of the methods. For each species, two isolates were obtained from the intestines of their respective hosts: T. canis and T. leonina from dogs, and T. cati from cats. For all isolates, total DNA was extracted using six different methods, including grinding, boiling, crushing, beating, freeze-thawing and the use of a commercial kit. To evaluate the efficacy of each method, the internal transcribed spacer (ITS) region and the cytochrome c oxidase subunit 1 (cox1) gene were chosen as representative markers for ribosomal and mitochondrial DNA, respectively. Among the six DNA extraction methods, the beating method was the most cost effective for all three species, followed by the commercial kit. Both methods produced high intensity bands on agarose gels and were characterized by no or minimal smear formation, depending on gene target; however, beating was less expensive. We therefore recommend the beating method for studies where costs need to be kept at low levels. Copyright © 2013 Elsevier Inc. All rights reserved.

Neural theory for the perception of causal actions.

PubMed

Fleischer, Falk; Christensen, Andrea; Caggiano, Vittorio; Thier, Peter; Giese, Martin A

2012-07-01

The efficient prediction of the behavior of others requires the recognition of their actions and an understanding of their action goals. In humans, this process is fast and extremely robust, as demonstrated by classical experiments showing that human observers reliably judge causal relationships and attribute interactive social behavior to strongly simplified stimuli consisting of simple moving geometrical shapes. While psychophysical experiments have identified critical visual features that determine the perception of causality and agency from such stimuli, the underlying detailed neural mechanisms remain largely unclear, and it is an open question why humans developed this advanced visual capability at all. We created pairs of naturalistic and abstract stimuli of hand actions that were exactly matched in terms of their motion parameters. We show that varying critical stimulus parameters for both stimulus types leads to very similar modulations of the perception of causality. However, the additional form information about the hand shape and its relationship with the object supports more fine-grained distinctions for the naturalistic stimuli. Moreover, we show that a physiologically plausible model for the recognition of goal-directed hand actions reproduces the observed dependencies of causality perception on critical stimulus parameters. These results support the hypothesis that selectivity for abstract action stimuli might emerge from the same neural mechanisms that underlie the visual processing of natural goal-directed action stimuli. Furthermore, the model proposes specific detailed neural circuits underlying this visual function, which can be evaluated in future experiments.

Gender difference in the theta/alpha ratio during the induction of peaceful audiovisual modalities.

PubMed

Yang, Chia-Yen; Lin, Ching-Po

2015-09-01

Gender differences in emotional perception have been found in numerous psychological and psychophysiological studies. The conducting modalities in diverse characteristics of different sensory systems make it interesting to determine how cooperation and competition contribute to emotional experiences. We have previously estimated the bias from the match attributes of auditory and visual modalities and revealed specific brain activity frequency patterns related to a peaceful mood. In that multimodality experiment, we focused on how inner-quiet information is processed in the human brain, and found evidence of auditory domination from the theta-band activity. However, a simple quantitative description of these three frequency bands is lacking, and no studies have assessed the effects of peacefulness on the emotional state. Therefore, the aim of this study was to use magnetoencephalography to determine if gender differences exist (and when and where) in the frequency interactions underpinning the perception of peacefulness. This study provides evidence of auditory and visual domination in perceptual bias during multimodality processing of peaceful consciousness. The results of power ratio analyses suggest that the values of the theta/alpha ratio are associated with a modality as well as hemispheric asymmetries in the anterior-to-posterior direction, which shift from right to left with the auditory to visual stimulations in a peaceful mood. This means that the theta/alpha ratio might be useful for evaluating emotion. Moreover, the difference was found to be most pronounced for auditory domination and visual sensitivity in the female group.

Local coding based matching kernel method for image classification.

PubMed

Song, Yan; McLoughlin, Ian Vince; Dai, Li-Rong

2014-01-01

This paper mainly focuses on how to effectively and efficiently measure visual similarity for local feature based representation. Among existing methods, metrics based on Bag of Visual Word (BoV) techniques are efficient and conceptually simple, at the expense of effectiveness. By contrast, kernel based metrics are more effective, but at the cost of greater computational complexity and increased storage requirements. We show that a unified visual matching framework can be developed to encompass both BoV and kernel based metrics, in which local kernel plays an important role between feature pairs or between features and their reconstruction. Generally, local kernels are defined using Euclidean distance or its derivatives, based either explicitly or implicitly on an assumption of Gaussian noise. However, local features such as SIFT and HoG often follow a heavy-tailed distribution which tends to undermine the motivation behind Euclidean metrics. Motivated by recent advances in feature coding techniques, a novel efficient local coding based matching kernel (LCMK) method is proposed. This exploits the manifold structures in Hilbert space derived from local kernels. The proposed method combines advantages of both BoV and kernel based metrics, and achieves a linear computational complexity. This enables efficient and scalable visual matching to be performed on large scale image sets. To evaluate the effectiveness of the proposed LCMK method, we conduct extensive experiments with widely used benchmark datasets, including 15-Scenes, Caltech101/256, PASCAL VOC 2007 and 2011 datasets. Experimental results confirm the effectiveness of the relatively efficient LCMK method.

Synaptic Mechanisms Generating Orientation Selectivity in the ON Pathway of the Rabbit Retina

PubMed Central

Venkataramani, Sowmya

2016-01-01

Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input. SIGNIFICANCE STATEMENT A core goal for visual neuroscientists is to understand how neural circuits at each stage of the visual system extract and encode features from the visual scene. This study documents a novel type of orientation-selective ganglion cell in the retina and shows that the receptive field structure is remarkably similar to that of simple cells in primary visual cortex. However, the data indicate that, unlike in the cortex, orientation selectivity in the retina depends on the activity of inhibitory interneurons. The results further reveal the physiological basis for feature detection in the visual system, elucidate the synaptic mechanisms that generate orientation selectivity at an early stage of visual processing, and illustrate a novel role for NMDA receptors in retinal processing. PMID:26985041

Synaptic Mechanisms Generating Orientation Selectivity in the ON Pathway of the Rabbit Retina.

PubMed

Venkataramani, Sowmya; Taylor, W Rowland

2016-03-16

Neurons that signal the orientation of edges within the visual field have been widely studied in primary visual cortex. Much less is known about the mechanisms of orientation selectivity that arise earlier in the visual stream. Here we examine the synaptic and morphological properties of a subtype of orientation-selective ganglion cell in the rabbit retina. The receptive field has an excitatory ON center, flanked by excitatory OFF regions, a structure similar to simple cell receptive fields in primary visual cortex. Examination of the light-evoked postsynaptic currents in these ON-type orientation-selective ganglion cells (ON-OSGCs) reveals that synaptic input is mediated almost exclusively through the ON pathway. Orientation selectivity is generated by larger excitation for preferred relative to orthogonal stimuli, and conversely larger inhibition for orthogonal relative to preferred stimuli. Excitatory orientation selectivity arises in part from the morphology of the dendritic arbors. Blocking GABAA receptors reduces orientation selectivity of the inhibitory synaptic inputs and the spiking responses. Negative contrast stimuli in the flanking regions produce orientation-selective excitation in part by disinhibition of a tonic NMDA receptor-mediated input arising from ON bipolar cells. Comparison with earlier studies of OFF-type OSGCs indicates that diverse synaptic circuits have evolved in the retina to detect the orientation of edges in the visual input. A core goal for visual neuroscientists is to understand how neural circuits at each stage of the visual system extract and encode features from the visual scene. This study documents a novel type of orientation-selective ganglion cell in the retina and shows that the receptive field structure is remarkably similar to that of simple cells in primary visual cortex. However, the data indicate that, unlike in the cortex, orientation selectivity in the retina depends on the activity of inhibitory interneurons. The results further reveal the physiological basis for feature detection in the visual system, elucidate the synaptic mechanisms that generate orientation selectivity at an early stage of visual processing, and illustrate a novel role for NMDA receptors in retinal processing. Copyright © 2016 the authors 0270-6474/16/363336-14$15.00/0.

STAR (Simple Targeted Arterial Rendering) Technique: a Novel and Simple Method to Visualize the Fetal Cardiac Outflow Tracts

PubMed Central

Yeo, Lami; Romero, Roberto; Jodicke, Cristiano; Kim, Sun Kwon; Gonzalez, Juan M.; Oggè, Giovanna; Lee, Wesley; Kusanovic, Juan Pedro; Vaisbuch, Edi; Hassan, Sonia S.

2010-01-01

Objective To describe a novel and simple technique (STAR: Simple Targeted Arterial Rendering) to visualize the fetal cardiac outflow tracts from dataset volumes obtained with spatiotemporal image correlation (STIC) and applying a new display technology (OmniView). Methods We developed a technique to image the outflow tracts by drawing three dissecting lines through the four-chamber view of the heart contained in a STIC volume dataset. Each line generated the following plane: 1) Line 1: ventricular septum “en face” with both great vessels (pulmonary artery anterior to the aorta); 2) Line 2: pulmonary artery with continuation into the longitudinal view of the ductal arch; and 3) Line 3: long axis view of the aorta arising from the left ventricle. The pattern formed by all 3 lines intersecting approximately through the crux of the heart resembles a “star”. The technique was then tested in 50 normal hearts (15.3 – 40.4 weeks of gestation). To determine if the technique could identify planes that departed from the normal images, we tested the technique in 4 cases with proven congenital heart defects (ventricular septal defect, transposition of great vessels, tetralogy of Fallot, and pulmonary atresia with intact ventricular septum). Results The STAR technique was able to generate the intended planes in all 50 normal cases. In the abnormal cases, the STAR technique allowed identification of the ventricular septal defect, demonstrated great vessel anomalies, and displayed views that deviated from what was expected from the examination of normal hearts. Conclusions This novel and simple technique can be used to visualize the outflow tracts and ventricular septum “en face” in normal fetal hearts. The inability to obtain expected views or the appearance of abnormal views in the generated planes should raise the index of suspicion for congenital heart disease involving the great vessels and/or the ventricular septum. The STAR technique may simplify examination of the fetal heart and could reduce operator dependency. PMID:20878672

Zipf’s word frequency law in natural language: A critical review and future directions

PubMed Central

2014-01-01

The frequency distribution of words has been a key object of study in statistical linguistics for the past 70 years. This distribution approximately follows a simple mathematical form known as Zipf ’ s law. This article first shows that human language has a highly complex, reliable structure in the frequency distribution over and above this classic law, although prior data visualization methods have obscured this fact. A number of empirical phenomena related to word frequencies are then reviewed. These facts are chosen to be informative about the mechanisms giving rise to Zipf’s law and are then used to evaluate many of the theoretical explanations of Zipf’s law in language. No prior account straightforwardly explains all the basic facts or is supported with independent evaluation of its underlying assumptions. To make progress at understanding why language obeys Zipf’s law, studies must seek evidence beyond the law itself, testing assumptions and evaluating novel predictions with new, independent data. PMID:24664880

Identification of a practical and reliable method for the evaluation of litter moisture in turkey production.

PubMed

Vinco, L J; Giacomelli, S; Campana, L; Chiari, M; Vitale, N; Lombardi, G; Veldkamp, T; Hocking, P M

2018-02-01

1. An experiment was conducted to compare 5 different methods for the evaluation of litter moisture. 2. For litter collection and assessment, 55 farms were selected, one shed from each farm was inspected and 9 points were identified within each shed. 3. For each device, used for the evaluation of litter moisture, mean and standard deviation of wetness measures per collection point were assessed. 4. The reliability and overall consistency between the 5 instruments used to measure wetness were high (α = 0.72). 5. Measurement of three out of the 9 collection points were sufficient to provide a reliable assessment of litter moisture throughout the shed. 6. Based on the direct correlation between litter moisture and footpad lesions, litter moisture measurement can be used as a resource based on-farm animal welfare indicator. 7. Among the 5 methods analysed, visual scoring is the most simple and practical, and therefore the best candidate to be used on-farm for animal welfare assessment.

Identification and detection of simple 3D objects with severely blurred vision.

PubMed

Kallie, Christopher S; Legge, Gordon E; Yu, Deyue

2012-12-05

Detecting and recognizing three-dimensional (3D) objects is an important component of the visual accessibility of public spaces for people with impaired vision. The present study investigated the impact of environmental factors and object properties on the recognition of objects by subjects who viewed physical objects with severely reduced acuity. The experiment was conducted in an indoor testing space. We examined detection and identification of simple convex objects by normally sighted subjects wearing diffusing goggles that reduced effective acuity to 20/900. We used psychophysical methods to examine the effect on performance of important environmental variables: viewing distance (from 10-24 feet, or 3.05-7.32 m) and illumination (overhead fluorescent and artificial window), and object variables: shape (boxes and cylinders), size (heights from 2-6 feet, or 0.61-1.83 m), and color (gray and white). Object identification was significantly affected by distance, color, height, and shape, as well as interactions between illumination, color, and shape. A stepwise regression analysis showed that 64% of the variability in identification could be explained by object contrast values (58%) and object visual angle (6%). When acuity is severely limited, illumination, distance, color, height, and shape influence the identification and detection of simple 3D objects. These effects can be explained in large part by the impact of these variables on object contrast and visual angle. Basic design principles for improving object visibility are discussed.

Format guidelines to make them vivid, intuitive, and visual: use simple formatting rules to optimize usability and accessibility of clinical practice guidelines.

PubMed

Versloot, Judith; Grudniewicz, Agnes; Chatterjee, Ananda; Hayden, Leigh; Kastner, Monika; Bhattacharyya, Onil

2015-06-01

We present simple formatting rules derived from an extensive literature review that can improve the format of clinical practice guidelines (CPGs), and potentially increase the likelihood of being used. We recently conducted a review of the literature from medicine, psychology, design, and human factors engineering on characteristics of guidelines that are associated with their use in practice, covering both the creation and communication of content. The formatting rules described in this article are derived from that review. The formatting rules are grouped into three categories that can be easily applied to CPGs: first, Vivid: make it stand out; second, Intuitive: match it to the audience's expectations, and third, Visual: use alternatives to text. We highlight rules supported by our broad literature review and provide specific 'how to' recommendations for individuals and groups developing evidence-based materials for clinicians. The way text documents are formatted influences their accessibility and usability. Optimizing the formatting of CPGs is a relatively inexpensive intervention and can be used to facilitate the dissemination of evidence in healthcare. Applying simple formatting principles to make documents more vivid, intuitive, and visual is a practical approach that has the potential to influence the usability of guidelines and to influence the extent to which guidelines are read, remembered, and used in practice.

Simple Machines. Physical Science in Action[TM]. Schlessinger Science Library. [Videotape].

ERIC Educational Resources Information Center

2000

In today's world, kids are aware that there are machines all around them. What they may not realize is that the function of all machines is to make work easier in some way. Simple Machines uses engaging visuals and colorful graphics to explain the concept of work and how humans use certain basic tools to help get work done. Students will learn…

Development of a rapid and simple Agrobacterium tumefaciens mediated transformation system for the fungal pathogen Heterobasidion annosum

Treesearch

Nicklas Samils; Malin Elfstrand; Daniel L. Lindner Czederpiltz; Jan Fahleson; Ake Olson; Christina Dixelius; Jan Stenlid

2006-01-01

Heterobasidion annosum causes root and butt-rot in trees and is the most serious forest pathogen in the northern hemisphere. We developed a rapid and simple Agrobacterium-mediated method of gene delivery into H. annosum to be used in functional studies of candidate genes and for visualization of mycelial interactions. Heterobasidion annosum TC 32-1 was cocultivated at...

An insect-inspired model for visual binding II: functional analysis and visual attention.

PubMed

Northcutt, Brandon D; Higgins, Charles M

2017-04-01

We have developed a neural network model capable of performing visual binding inspired by neuronal circuitry in the optic glomeruli of flies: a brain area that lies just downstream of the optic lobes where early visual processing is performed. This visual binding model is able to detect objects in dynamic image sequences and bind together their respective characteristic visual features-such as color, motion, and orientation-by taking advantage of their common temporal fluctuations. Visual binding is represented in the form of an inhibitory weight matrix which learns over time which features originate from a given visual object. In the present work, we show that information represented implicitly in this weight matrix can be used to explicitly count the number of objects present in the visual image, to enumerate their specific visual characteristics, and even to create an enhanced image in which one particular object is emphasized over others, thus implementing a simple form of visual attention. Further, we present a detailed analysis which reveals the function and theoretical limitations of the visual binding network and in this context describe a novel network learning rule which is optimized for visual binding.

Retinal Spectral Domain Optical Coherence Tomography in Early Atrophic Age-Related Macular Degeneration (AMD) and a New Metric for Objective Evaluation of the Efficacy of Ocular Nutrition

PubMed Central

Richer, Stuart; Cho, Jane; Stiles, William; Levin, Marc; Wrobel, James S.; Sinai, Michael; Thomas, Carla

2012-01-01

Purpose: A challenge in ocular preventive medicine is identification of patients with early pathological retinal damage that might benefit from nutritional intervention. The purpose of this study is to evaluate retinal thinning (RT) in early atrophic age-related macular degeneration (AMD) against visual function data from the Zeaxanthin and Visual Function (ZVF) randomized double masked placebo controlled clinical trial (FDA IND #78973). Methods: Retrospective, observational case series of medical center veterans with minimal visible AMD retinopathy (AREDS Report #18 simplified grading 1.4/4.0 bilateral retinopathy). Foveal and extra-foveal four quadrant SDOCT RT measurements were evaluated in n = 54 clinical and ZVF AMD patients. RT by age was determined and compared to the OptoVue SD OCT normative database. RT by quadrant in a subset of n = 29 ZVF patients was correlated with contrast sensitivity and parafoveal blue cone increment thresholds. Results: Foveal RT in AMD patients and non-AMD patients was preserved with age. Extrafoveal regions, however, showed significant slope differences between AMD patients and non-AMD patients, with the superior and nasal quadrants most vulnerable to retinal thinning (sup quad: −5.5 μm/decade thinning vs. Non-AMD: −1.1 μm/decade, P < 0.02; nasal quad: −5.0 μm/decade thinning vs. Non-AMD: −1.0 μm/decade, P < 0.04). Two measures of extrafoveal visual deterioration were correlated: A significant inverse correlation between % RT and contrast sensitivity (r = −0.33, P = 0.01, 2 Tailed Paired T) and an elevated extrafoveal increment blue cone threshold (r = +0.34, P = 0.01, 2 Tailed T). Additional SD OCT RT data for the non-AMD oldest age group (ages 82–91) is needed to fully substantiate the model. Conclusion: A simple new SD OCT clinical metric called “% extra-foveal RT” correlates well with functional visual loss in early AMD patients having minimal visible retinopathy. This metric can be used to follow the effect of repleting ocular nutrients, such as zinc, antioxidants, carotenoids, n-3 essential fats , resveratrol and vitamin D. PMID:23363992

Uncertainty Footprint: Visualization of Nonuniform Behavior of Iterative Algorithms Applied to 4D Cell Tracking

PubMed Central

Wan, Y.; Hansen, C.

2018-01-01

Research on microscopy data from developing biological samples usually requires tracking individual cells over time. When cells are three-dimensionally and densely packed in a time-dependent scan of volumes, tracking results can become unreliable and uncertain. Not only are cell segmentation results often inaccurate to start with, but it also lacks a simple method to evaluate the tracking outcome. Previous cell tracking methods have been validated against benchmark data from real scans or artificial data, whose ground truth results are established by manual work or simulation. However, the wide variety of real-world data makes an exhaustive validation impossible. Established cell tracking tools often fail on new data, whose issues are also difficult to diagnose with only manual examinations. Therefore, data-independent tracking evaluation methods are desired for an explosion of microscopy data with increasing scale and resolution. In this paper, we propose the uncertainty footprint, an uncertainty quantification and visualization technique that examines nonuniformity at local convergence for an iterative evaluation process on a spatial domain supported by partially overlapping bases. We demonstrate that the patterns revealed by the uncertainty footprint indicate data processing quality in two algorithms from a typical cell tracking workflow – cell identification and association. A detailed analysis of the patterns further allows us to diagnose issues and design methods for improvements. A 4D cell tracking workflow equipped with the uncertainty footprint is capable of self diagnosis and correction for a higher accuracy than previous methods whose evaluation is limited by manual examinations. PMID:29456279

How low can you go? Changing the resolution of novel complex objects in visual working memory according to task demands

PubMed Central

Allon, Ayala S.; Balaban, Halely; Luria, Roy

2014-01-01

In three experiments we manipulated the resolution of novel complex objects in visual working memory (WM) by changing task demands. Previous studies that investigated the trade-off between quantity and resolution in visual WM yielded mixed results for simple familiar stimuli. We used the contralateral delay activity as an electrophysiological marker to directly track the deployment of visual WM resources while participants preformed a change-detection task. Across three experiments we presented the same novel complex items but changed the task demands. In Experiment 1 we induced a medium resolution task by using change trials in which a random polygon changed to a different type of polygon and replicated previous findings showing that novel complex objects are represented with higher resolution relative to simple familiar objects. In Experiment 2 we induced a low resolution task that required distinguishing between polygons and other types of stimulus categories, but we failed in finding a corresponding decrease in the resolution of the represented item. Finally, in Experiment 3 we induced a high resolution task that required discriminating between highly similar polygons with somewhat different contours. This time, we observed an increase in the item’s resolution. Our findings indicate that the resolution for novel complex objects can be increased but not decreased according to task demands, suggesting that minimal resolution is required in order to maintain these items in visual WM. These findings support studies claiming that capacity and resolution in visual WM reflect different mechanisms. PMID:24734026

Audiovisual correspondence between musical timbre and visual shapes

PubMed Central

Adeli, Mohammad; Rouat, Jean; Molotchnikoff, Stéphane

2014-01-01

This article investigates the cross-modal correspondences between musical timbre and shapes. Previously, such features as pitch, loudness, light intensity, visual size, and color characteristics have mostly been used in studies of audio-visual correspondences. Moreover, in most studies, simple stimuli e.g., simple tones have been utilized. In this experiment, 23 musical sounds varying in fundamental frequency and timbre but fixed in loudness were used. Each sound was presented once against colored shapes and once against grayscale shapes. Subjects had to select the visual equivalent of a given sound i.e., its shape, color (or grayscale) and vertical position. This scenario permitted studying the associations between normalized timbre and visual shapes as well as some of the previous findings for more complex stimuli. One hundred and nineteen subjects (31 females and 88 males) participated in the online experiment. Subjects included 36 claimed professional musicians, 47 claimed amateur musicians, and 36 claimed non-musicians. Thirty-one subjects have also claimed to have synesthesia-like experiences. A strong association between timbre of envelope normalized sounds and visual shapes was observed. Subjects have strongly associated soft timbres with blue, green or light gray rounded shapes, harsh timbres with red, yellow or dark gray sharp angular shapes and timbres having elements of softness and harshness together with a mixture of the two previous shapes. Color or grayscale had no effect on timbre-shape associations. Fundamental frequency was not associated with height, grayscale or color. The significant correspondence between timbre and shape revealed by the present work allows designing substitution systems which might help the blind to perceive shapes through timbre. PMID:24910604

Three-dimensional visualization maps of suspended-sediment concentrations during placement of dredged material in 21st Avenue West Channel Embayment, Duluth-Superior Harbor, Duluth, Minnesota, 2015

USGS Publications Warehouse

Groten, Joel T.; Ellison, Christopher A.; Mahoney, Mollie H.

2016-06-30

Excess sediment in rivers and estuaries poses serious environmental and economic challenges. The U.S. Army Corps of Engineers (USACE) routinely dredges sediment in Federal navigation channels to maintain commercial shipping operations. The USACE initiated a 3-year pilot project in 2013 to use navigation channel dredged material to aid in restoration of shoreline habitat in the 21st Avenue West Channel Embayment of the Duluth-Superior Harbor. Placing dredged material in the 21st Avenue West Channel Embayment supports the restoration of shallow bay aquatic habitat aiding in the delisting of the St. Louis River Estuary Area of Concern.The U.S. Geological Survey, in cooperation with the USACE, collected turbidity and suspended-sediment concentrations (SSCs) in 2014 and 2015 to measure the horizontal and vertical distribution of SSCs during placement operations of dredged materials. These data were collected to help the USACE evaluate the use of several best management practices, including various dredge material placement techniques and a silt curtain, to mitigate the dispersion of suspended sediment.Three-dimensional visualization maps are a valuable tool for assessing the spatial displacement of SSCs. Data collection was designed to coincide with four dredged placement configurations that included periods with and without a silt curtain as well as before and after placement of dredged materials. Approximately 230 SSC samples and corresponding turbidity values collected in 2014 and 2015 were used to develop a simple linear regression model between SSC and turbidity. Using the simple linear regression model, SSCs were estimated for approximately 3,000 turbidity values at approximately 100 sampling sites in the 21st Avenue West Channel Embayment of the Duluth-Superior Harbor. The estimated SSCs served as input for development of 12 three-dimensional visualization maps.

Piloted simulator investigation of helicopter control systems effects on handling qualities during instrument flight

NASA Technical Reports Server (NTRS)

Forrest, R. D.; Chen, R. T. N.; Gerdes, R. M.; Alderete, T. S.; Gee, D. R.

1979-01-01

An exploratory piloted simulation was conducted to investigate the effects of the characteristics of helicopter flight control systems on instrument flight handling qualities. This joint FAA/NASA study was motivated by the need to improve instrument flight capability. A near-term objective is to assist in updating the airworthiness criteria for helicopter instrument flight. The experiment consisted of variations of single-rotor helicopter types and levels of stability and control augmentation systems (SCAS). These configurations were evaluated during an omnirange approach task under visual and instrument flight conditions. The levels of SCAS design included a simple rate damping system, collective decoupling plus rate damping, and an attitude command system with collective decoupling. A limited evaluation of stick force versus airspeed stability was accomplished. Some problems were experienced with control system mechanization which had a detrimental effect on longitudinal stability. Pilot ratings, pilot commentary, and performance data related to the task are presented.

Gestures in an Intelligent User Interface

NASA Astrophysics Data System (ADS)

Fikkert, Wim; van der Vet, Paul; Nijholt, Anton

In this chapter we investigated which hand gestures are intuitive to control a large display multimedia interface from a user's perspective. Over the course of two sequential user evaluations, we defined a simple gesture set that allows users to fully control a large display multimedia interface, intuitively. First, we evaluated numerous gesture possibilities for a set of commands that can be issued to the interface. These gestures were selected from literature, science fiction movies, and a previous exploratory study. Second, we implemented a working prototype with which the users could interact with both hands and the preferred hand gestures with 2D and 3D visualizations of biochemical structures. We found that the gestures are influenced to significant extent by the fast paced developments in multimedia interfaces such as the Apple iPhone and the Nintendo Wii and to no lesser degree by decades of experience with the more traditional WIMP-based interfaces.

An Investigation of Large Tilt-Rotor Short-Term Attitude Response Handling Qualities Requirements in Hover

NASA Technical Reports Server (NTRS)

Malcipa, Carlos; Decker, William A.; Theodore, Colin R.; Blanken, Christopher L.; Berger, Tom

2010-01-01

A piloted simulation investigation was conducted using the NASA Ames Vertical Motion Simulator to study the impact of pitch, roll and yaw attitude bandwidth and phase delay on handling qualities of large tilt-rotor aircraft. Multiple bandwidth and phase delay pairs were investigated for each axis. The simulation also investigated the effect that the pilot offset from the center of gravity has on handling qualities. While pilot offset does not change the dynamics of the vehicle, it does affect the proprioceptive and visual cues and it can have an impact on handling qualities. The experiment concentrated on two primary evaluation tasks: a precision hover task and a simple hover pedal turn. Six pilots flew over 1400 data runs with evaluation comments and objective performance data recorded. The paper will describe the experiment design and methodology, discuss the results of the experiment and summarize the findings.

Visual but not motor processes predict simple visuomotor reaction time of badminton players.

PubMed

Hülsdünker, Thorben; Strüder, Heiko K; Mierau, Andreas

2018-03-01

The athlete's brain exhibits significant functional adaptations that facilitate visuomotor reaction performance. However, it is currently unclear if the same neurophysiological processes that differentiate athletes from non-athletes also determine performance within a homogeneous group of athletes. This information can provide valuable help for athletes and coaches aiming to optimize existing training regimes. Therefore, this study aimed to identify the neurophysiological correlates of visuomotor reaction performance in a group of skilled athletes. In 36 skilled badminton athletes, electroencephalography (EEG) was used to investigate pattern reversal and motion onset visual-evoked potentials (VEPs) as well as visuomotor reaction time (VMRT) during a simple reaction task. Stimulus-locked and response-locked event-related potentials (ERPs) in visual and motor regions as well as the onset of muscle activation (EMG onset) were determined. Correlation and multiple regression analyses identified the neurophysiological parameters predicting EMG onset and VMRT. For pattern reversal stimuli, the P100 latency and age best predicted EMG onset (r = 0.43; p = .003) and VMRT (r = 0.62; p = .001). In the motion onset experiment, EMG onset (r = 0.80; p < .001) and VMRT (r = 0.78; p < .001) were predicted by N2 latency and age. In both conditions, cortical potentials in motor regions were not correlated with EMG onset or VMRT. It is concluded that previously identified neurophysiological parameters differentiating athletes from non-athletes do not necessarily determine performance within a homogeneous group of athletes. Specifically, the speed of visual perception/processing predicts EMG onset and VMRT in skilled badminton players while motor-related processes, although differentiating athletes from non-athletes, are not associated simple with visuomotor reaction performance.

Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods

PubMed Central

2010-01-01

Background Citrus Bacterial Canker (CBC) is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is Xanthomonas citri subsp. citri, while Xanthomonas fuscans subsp. aurantifolii, strain B causes type B CBC and Xanthomonas fuscans subsp. aurantifolii strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR) have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP), which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment. Results A loop-mediated isothermal amplification assay for the diagnosis of Citrus Bacterial Canker (CBC-LAMP) was developed and evaluated. DNA samples were obtained from infected plants or cultured bacteria. A typical ladder-like pattern on gel electrophoresis was observed in all positive samples in contrast to the negative controls. In addition, amplification products were detected by visual inspection using SYBRGreen and using a lateral flow dipstick, eliminating the need for gel electrophoresis. The sensitivity and specificity of the assay were evaluated in different conditions and using several sample sources which included purified DNA, bacterium culture and infected plant tissue. The sensitivity of the CBC-LAMP was 10 fg of pure Xcc DNA, 5 CFU in culture samples and 18 CFU in samples of infected plant tissue. No cross reaction was observed with DNA of other phytopathogenic bacteria. The assay was capable of detecting CBC-causing strains from several geographical origins and pathotypes. Conclusions The CBC-LAMP technique is a simple, fast, sensitive and specific method for the diagnosis of Citrus Bacterial Canker. This method can be useful in the phytosanitary programs of the citrus industry worldwide. PMID:20565886

Postoperative liver volume was accurately predicted by a medical image three dimensional visualization system in hepatectomy for liver cancer.

PubMed

Cai, Wei; Fan, Yingfang; Hu, Haoyu; Xiang, Nan; Fang, Chihua; Jia, Fucang

2017-06-01

Liver cancer is the second most common cause of cancer death worldwide. The hepatectomy is the most effective and the only potentially curative treatment for patients with resectable neoplasm. Precisely preoperative assessment of remnant liver volume is essential in preventing postoperative liver failure. The aim of our study is to report our experience of using a medical image three dimensional (3D) visualization system (MI-3DVS), which was developed by our team, in assisting hepatectomy for patients with liver cancer. Between January 2010 and June 2016, 69 patients with liver cancer underwent hepatic resection based on the MI-3DVS were enrolled in this study. All patients underwent CT scan 5 days before the surgery and within 5 days after resection. CT images were reconstructed with the MI-3DVS to assist to perform hepatectomy. Simple linear regression, intra-class correlation coefficient (ICC) and Bland-Altman analysis were used to evaluate the relationship and agreement between actual excisional liver volume (AELV) and predicted excisional liver volume (PELV). Among 69 patients in this study, 62(89.85%) of them were diagnosed with hepatocellular carcinoma by histopathologic examination, and 41(59.42%) underwent major hepatectomy. The average AELV was 330.13 cm 3 and the average PELV was 287.67 cm 3 . The simple regression equation is AELV = 1.016 × PELV+30.39(r = 0.966; p < 0.0003). PELV (ICC = 0.964) achieved an excellent agreement with AELV with statistical significance (p < 0.001). 65 of 69 dots are in the range of 95% confidence interval in Bland-Altman analyses. The MI-3DVS has advantages of simple usage and convenient hold. It is accurate in assessment of postoperative liver volume and improve safety in liver resection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simple quality assurance method of dynamic tumor tracking with the gimbaled linac system using a light field.

PubMed

Miura, Hideharu; Ozawa, Shuichi; Hayata, Masahiro; Tsuda, Shintaro; Yamada, Kiyoshi; Nagata, Yasushi

2016-09-08

We proposed a simple visual method for evaluating the dynamic tumor tracking (DTT) accuracy of a gimbal mechanism using a light field. A single photon beam was set with a field size of 30 × 30 mm2 at a gantry angle of 90°. The center of a cube phantom was set up at the isocenter of a motion table, and 4D modeling was performed based on the tumor and infrared (IR) marker motion. After 4D modeling, the cube phantom was replaced with a sheet of paper, which was placed perpen-dicularly, and a light field was projected on the sheet of paper. The light field was recorded using a web camera in a treatment room that was as dark as possible. Calculated images from each image obtained using the camera were summed to compose a total summation image. Sinusoidal motion sequences were produced by moving the phantom with a fixed amplitude of 20 mm and different breathing periods of 2, 4, 6, and 8 s. The light field was projected on the sheet of paper under three conditions: with the moving phantom and DTT based on the motion of the phantom, with the moving phantom and non-DTT, and with a stationary phantom for comparison. The values of tracking errors using the light field were 1.12 ± 0.72, 0.31 ± 0.19, 0.27 ± 0.12, and 0.15 ± 0.09 mm for breathing periods of 2, 4, 6, and 8s, respectively. The tracking accuracy showed dependence on the breath-ing period. We proposed a simple quality assurance (QA) process for the tracking accuracy of a gimbal mechanism system using a light field and web camera. Our method can assess the tracking accuracy using a light field without irradiation and clearly visualize distributions like film dosimetry. © 2016 The Authors.

How can we improve crop genotypes to increase stress resilience and productivity in a future climate? A new crop screening method based on productivity and resistance to abiotic stress

PubMed Central

Thiry, Arnauld A.; Chavez Dulanto, Perla N.; Reynolds, Matthew P.; Davies, William J.

2016-01-01

The need to accelerate the selection of crop genotypes that are both resistant to and productive under abiotic stress is enhanced by global warming and the increase in demand for food by a growing world population. In this paper, we propose a new method for evaluation of wheat genotypes in terms of their resilience to stress and their production capacity. The method quantifies the components of a new index related to yield under abiotic stress based on previously developed stress indices, namely the stress susceptibility index, the stress tolerance index, the mean production index, the geometric mean production index, and the tolerance index, which were created originally to evaluate drought adaptation. The method, based on a scoring scale, offers simple and easy visualization and identification of resilient, productive and/or contrasting genotypes according to grain yield. This new selection method could help breeders and researchers by defining clear and strong criteria to identify genotypes with high resilience and high productivity and provide a clear visualization of contrasts in terms of grain yield production under stress. It is also expected that this methodology will reduce the time required for first selection and the number of first-selected genotypes for further evaluation by breeders and provide a basis for appropriate comparisons of genotypes that would help reveal the biology behind high stress productivity of crops. PMID:27677299

Perception, Cognition, and Effectiveness of Visualizations with Applications in Science and Engineering

NASA Astrophysics Data System (ADS)

Borkin, Michelle A.

Visualization is a powerful tool for data exploration and analysis. With data ever-increasing in quantity and becoming integrated into our daily lives, having effective visualizations is necessary. But how does one design an effective visualization? To answer this question we need to understand how humans perceive, process, and understand visualizations. Through visualization evaluation studies we can gain deeper insight into the basic perception and cognition theory of visualizations, both through domain-specific case studies as well as generalized laboratory experiments. This dissertation presents the results of four evaluation studies, each of which contributes new knowledge to the theory of perception and cognition of visualizations. The results of these studies include a deeper clearer understanding of how color, data representation dimensionality, spatial layout, and visual complexity affect a visualization's effectiveness, as well as how visualization types and visual attributes affect the memorability of a visualization. We first present the results of two domain-specific case study evaluations. The first study is in the field of biomedicine in which we developed a new heart disease diagnostic tool, and conducted a study to evaluate the effectiveness of 2D versus 3D data representations as well as color maps. In the second study, we developed a new visualization tool for filesystem provenance data with applications in computer science and the sciences more broadly. We additionally developed a new time-based hierarchical node grouping method. We then conducted a study to evaluate the effectiveness of the new tool with its radial layout versus the conventional node-link diagram, and the new node grouping method. Finally, we discuss the results of two generalized studies designed to understand what makes a visualization memorable. In the first evaluation we focused on visualization memorability and conducted an online study using Amazon's Mechanical Turk with hundreds of users and thousands of visualizations. For the second evaluation we designed an eye-tracking laboratory study to gain insight into precisely which elements of a visualization contribute to memorability as well as visualization recognition and recall.

WebScope: A New Tool for Fusion Data Analysis and Visualization

NASA Astrophysics Data System (ADS)

Yang, Fei; Dang, Ningning; Xiao, Bingjia

2010-04-01

A visualization tool was developed through a web browser based on Java applets embedded into HTML pages, in order to provide a world access to the EAST experimental data. It can display data from various trees in different servers in a single panel. With WebScope, it is easier to make a comparison between different data sources and perform a simple calculation over different data sources.

Aladin Lite: Lightweight sky atlas for browsers

NASA Astrophysics Data System (ADS)

Boch, Thomas

2014-02-01

Aladin Lite is a lightweight version of the Aladin tool, running in the browser and geared towards simple visualization of a sky region. It allows visualization of image surveys (JPEG multi-resolution HEALPix all-sky surveys) and permits superimposing tabular (VOTable) and footprints (STC-S) data. Aladin Lite is powered by HTML5 canvas technology and is easily embeddable on any web page and can also be controlled through a Javacript API.

Fabricated CeO2 nanopowders as a novel sensing platform for advanced forensic, electrochemical and photocatalytic applications

NASA Astrophysics Data System (ADS)

Rohini, B. S.; Nagabhushana, H.; Darshan, G. P.; Basavaraj, R. B.; Sharma, S. C.; Sudarmani, R.

2017-11-01

In Forensic investigation, identification of various types of ridge details are essential in order to fix the criminals associated in various crimes. Even though several methods and labeling agents are available to visualize latent finger prints (LFPs) there is still simple, accurate, cost-effective, and non-destructive tool is required. In the present work, CeO2 nanopowders (NPs) are prepared via simple solution combustion route using Tamarindus indica fruit extract as a fuel. The optimized NPs are utilized for visualization of LFPs on various surfaces by powder dusting method. Results revealed that visualized LFPs exhibit Level 3 features such as pores and ridge contours under normal light with high sensitivity and without background hindrance. The photometric characteristics of the prepared samples exhibit blue color emission and highly useful in warm light emitting diodes. The photocatalytic studies were carried out with different Methylene blue (MB) dye concentration and pH values. The obtained results reveal that the CeO2 NPs exhibits an excellent catalytic properties which can act as a good catalytic reagent. The findings demonstrate that the prepared NPs are quite useful as a labeling agent for visualization of LFPs, efficient catalysts for dye degradation as well as solid-state lighting applications.

Web-based visualization of gridded dataset usings OceanBrowser

NASA Astrophysics Data System (ADS)

Barth, Alexander; Watelet, Sylvain; Troupin, Charles; Beckers, Jean-Marie

2015-04-01

OceanBrowser is a web-based visualization tool for gridded oceanographic data sets. Those data sets are typically four-dimensional (longitude, latitude, depth and time). OceanBrowser allows one to visualize horizontal sections at a given depth and time to examine the horizontal distribution of a given variable. It also offers the possibility to display the results on an arbitrary vertical section. To study the evolution of the variable in time, the horizontal and vertical sections can also be animated. Vertical section can be generated by using a fixed distance from coast or fixed ocean depth. The user can customize the plot by changing the color-map, the range of the color-bar, the type of the plot (linearly interpolated color, simple contours, filled contours) and download the current view as a simple image or as Keyhole Markup Language (KML) file for visualization in applications such as Google Earth. The data products can also be accessed as NetCDF files and through OPeNDAP. Third-party layers from a web map service can also be integrated. OceanBrowser is used in the frame of the SeaDataNet project (http://gher-diva.phys.ulg.ac.be/web-vis/) and EMODNET Chemistry (http://oceanbrowser.net/emodnet/) to distribute gridded data sets interpolated from in situ observation using DIVA (Data-Interpolating Variational Analysis).

Toward Mixed Method Evaluations of Scientific Visualizations and Design Process as an Evaluation Tool.

PubMed

Jackson, Bret; Coffey, Dane; Thorson, Lauren; Schroeder, David; Ellingson, Arin M; Nuckley, David J; Keefe, Daniel F

2012-10-01

In this position paper we discuss successes and limitations of current evaluation strategies for scientific visualizations and argue for embracing a mixed methods strategy of evaluation. The most novel contribution of the approach that we advocate is a new emphasis on employing design processes as practiced in related fields (e.g., graphic design, illustration, architecture) as a formalized mode of evaluation for data visualizations. To motivate this position we describe a series of recent evaluations of scientific visualization interfaces and computer graphics strategies conducted within our research group. Complementing these more traditional evaluations our visualization research group also regularly employs sketching, critique, and other design methods that have been formalized over years of practice in design fields. Our experience has convinced us that these activities are invaluable, often providing much more detailed evaluative feedback about our visualization systems than that obtained via more traditional user studies and the like. We believe that if design-based evaluation methodologies (e.g., ideation, sketching, critique) can be taught and embraced within the visualization community then these may become one of the most effective future strategies for both formative and summative evaluations.

Toward Mixed Method Evaluations of Scientific Visualizations and Design Process as an Evaluation Tool

PubMed Central

Jackson, Bret; Coffey, Dane; Thorson, Lauren; Schroeder, David; Ellingson, Arin M.; Nuckley, David J.

2017-01-01

In this position paper we discuss successes and limitations of current evaluation strategies for scientific visualizations and argue for embracing a mixed methods strategy of evaluation. The most novel contribution of the approach that we advocate is a new emphasis on employing design processes as practiced in related fields (e.g., graphic design, illustration, architecture) as a formalized mode of evaluation for data visualizations. To motivate this position we describe a series of recent evaluations of scientific visualization interfaces and computer graphics strategies conducted within our research group. Complementing these more traditional evaluations our visualization research group also regularly employs sketching, critique, and other design methods that have been formalized over years of practice in design fields. Our experience has convinced us that these activities are invaluable, often providing much more detailed evaluative feedback about our visualization systems than that obtained via more traditional user studies and the like. We believe that if design-based evaluation methodologies (e.g., ideation, sketching, critique) can be taught and embraced within the visualization community then these may become one of the most effective future strategies for both formative and summative evaluations. PMID:28944349

Storage of features, conjunctions and objects in visual working memory.

PubMed

Vogel, E K; Woodman, G F; Luck, S J

2001-02-01

Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.

Treatment of visual neglect in elderly patients with stroke: a single-subject series using either a scanning and cueing strategy or a left-limb activation strategy.

PubMed

Bailey, Maggie J; Riddoch, M Jane; Crome, Peter

2002-08-01

The presence of unilateral visual neglect (UVN) may adversely affect functional recovery, and rehabilitation strategies that are practical for use in clinical settings are needed. The purpose of this study was to evaluate the use of 2 approaches to reduce UVN in people who have had strokes. Seven elderly patients with stroke and severe left UVN, aged 60 to 85 years, were recruited from a stroke rehabilitation unit. A nonconcurrent, multiple-baselines-across-subjects approach, with an A-B-A treatment-withdrawal single-subject experimental design, was used. Five subjects received a scanning and cueing approach, and 2 subjects received a contralesional limb activation approach, for 10 one-hour sessions. In the former approach, active scanning to the left was encouraged by the therapist, using visual and verbal cues and a mental imagery technique, during reading and copying tasks and simple board games. In the latter approach, functional and goal-oriented left upper-limb activities in neglected hemispace were encouraged. Unilateral visual neglect was examined by a masked (blinded) examiner throughout all phases using the Star Cancellation Test, the Line Bisection Test, and the Baking Tray Task. Data were analyzed using visual and inferential statistical techniques. Both subjects who received limb activation and 3 of the 5 subjects who received scanning and cueing showed a reduction in UVN in one or more tests. This improvement was maintained during the withdrawal phase. Both approaches had a positive effect of reducing aspects of UVN in some subjects relative to no-treatment baselines. However, causality cannot be assured in the absence of controls. The approaches are practical for use in rehabilitation settings. These procedures warrant further replication across subjects, settings, and therapists.

Comprehensive decision tree models in bioinformatics.

PubMed

Stiglic, Gregor; Kocbek, Simon; Pernek, Igor; Kokol, Peter

2012-01-01

Classification is an important and widely used machine learning technique in bioinformatics. Researchers and other end-users of machine learning software often prefer to work with comprehensible models where knowledge extraction and explanation of reasoning behind the classification model are possible. This paper presents an extension to an existing machine learning environment and a study on visual tuning of decision tree classifiers. The motivation for this research comes from the need to build effective and easily interpretable decision tree models by so called one-button data mining approach where no parameter tuning is needed. To avoid bias in classification, no classification performance measure is used during the tuning of the model that is constrained exclusively by the dimensions of the produced decision tree. The proposed visual tuning of decision trees was evaluated on 40 datasets containing classical machine learning problems and 31 datasets from the field of bioinformatics. Although we did not expected significant differences in classification performance, the results demonstrate a significant increase of accuracy in less complex visually tuned decision trees. In contrast to classical machine learning benchmarking datasets, we observe higher accuracy gains in bioinformatics datasets. Additionally, a user study was carried out to confirm the assumption that the tree tuning times are significantly lower for the proposed method in comparison to manual tuning of the decision tree. The empirical results demonstrate that by building simple models constrained by predefined visual boundaries, one not only achieves good comprehensibility, but also very good classification performance that does not differ from usually more complex models built using default settings of the classical decision tree algorithm. In addition, our study demonstrates the suitability of visually tuned decision trees for datasets with binary class attributes and a high number of possibly redundant attributes that are very common in bioinformatics.

Comprehensive Decision Tree Models in Bioinformatics

PubMed Central

Stiglic, Gregor; Kocbek, Simon; Pernek, Igor; Kokol, Peter

2012-01-01

Purpose Classification is an important and widely used machine learning technique in bioinformatics. Researchers and other end-users of machine learning software often prefer to work with comprehensible models where knowledge extraction and explanation of reasoning behind the classification model are possible. Methods This paper presents an extension to an existing machine learning environment and a study on visual tuning of decision tree classifiers. The motivation for this research comes from the need to build effective and easily interpretable decision tree models by so called one-button data mining approach where no parameter tuning is needed. To avoid bias in classification, no classification performance measure is used during the tuning of the model that is constrained exclusively by the dimensions of the produced decision tree. Results The proposed visual tuning of decision trees was evaluated on 40 datasets containing classical machine learning problems and 31 datasets from the field of bioinformatics. Although we did not expected significant differences in classification performance, the results demonstrate a significant increase of accuracy in less complex visually tuned decision trees. In contrast to classical machine learning benchmarking datasets, we observe higher accuracy gains in bioinformatics datasets. Additionally, a user study was carried out to confirm the assumption that the tree tuning times are significantly lower for the proposed method in comparison to manual tuning of the decision tree. Conclusions The empirical results demonstrate that by building simple models constrained by predefined visual boundaries, one not only achieves good comprehensibility, but also very good classification performance that does not differ from usually more complex models built using default settings of the classical decision tree algorithm. In addition, our study demonstrates the suitability of visually tuned decision trees for datasets with binary class attributes and a high number of possibly redundant attributes that are very common in bioinformatics. PMID:22479449

Frequency of gamma oscillations in humans is modulated by velocity of visual motion

PubMed Central

Butorina, Anna V.; Sysoeva, Olga V.; Prokofyev, Andrey O.; Nikolaeva, Anastasia Yu.; Stroganova, Tatiana A.

2015-01-01

Gamma oscillations are generated in networks of inhibitory fast-spiking (FS) parvalbumin-positive (PV) interneurons and pyramidal cells. In animals, gamma frequency is modulated by the velocity of visual motion; the effect of velocity has not been evaluated in humans. In this work, we have studied velocity-related modulations of gamma frequency in children using MEG/EEG. We also investigated whether such modulations predict the prominence of the “spatial suppression” effect (Tadin D, Lappin JS, Gilroy LA, Blake R. Nature 424: 312-315, 2003) that is thought to depend on cortical center-surround inhibitory mechanisms. MEG/EEG was recorded in 27 normal boys aged 8–15 yr while they watched high-contrast black-and-white annular gratings drifting with velocities of 1.2, 3.6, and 6.0°/s and performed a simple detection task. The spatial suppression effect was assessed in a separate psychophysical experiment. MEG gamma oscillation frequency increased while power decreased with increasing velocity of visual motion. In EEG, the effects were less reliable. The frequencies of the velocity-specific gamma peaks were 64.9, 74.8, and 87.1 Hz for the slow, medium, and fast motions, respectively. The frequency of the gamma response elicited during slow and medium velocity of visual motion decreased with subject age, whereas the range of gamma frequency modulation by velocity increased with age. The frequency modulation range predicted spatial suppression even after controlling for the effect of age. We suggest that the modulation of the MEG gamma frequency by velocity of visual motion reflects excitability of cortical inhibitory circuits and can be used to investigate their normal and pathological development in the human brain. PMID:25925324

User-Centered Evaluation of Visual Analytics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholtz, Jean C.

Visual analytics systems are becoming very popular. More domains now use interactive visualizations to analyze the ever-increasing amount and heterogeneity of data. More novel visualizations are being developed for more tasks and users. We need to ensure that these systems can be evaluated to determine that they are both useful and usable. A user-centered evaluation for visual analytics needs to be developed for these systems. While many of the typical human-computer interaction (HCI) evaluation methodologies can be applied as is, others will need modification. Additionally, new functionality in visual analytics systems needs new evaluation methodologies. There is a difference betweenmore » usability evaluations and user-centered evaluations. Usability looks at the efficiency, effectiveness, and user satisfaction of users carrying out tasks with software applications. User-centered evaluation looks more specifically at the utility provided to the users by the software. This is reflected in the evaluations done and in the metrics used. In the visual analytics domain this is very challenging as users are most likely experts in a particular domain, the tasks they do are often not well defined, the software they use needs to support large amounts of different kinds of data, and often the tasks last for months. These difficulties are discussed more in the section on User-centered Evaluation. Our goal is to provide a discussion of user-centered evaluation practices for visual analytics, including existing practices that can be carried out and new methodologies and metrics that need to be developed and agreed upon by the visual analytics community. The material provided here should be of use for both researchers and practitioners in the field of visual analytics. Researchers and practitioners in HCI and interested in visual analytics will find this information useful as well as a discussion on changes that need to be made to current HCI practices to make them more suitable to visual analytics. A history of analysis and analysis techniques and problems is provided as well as an introduction to user-centered evaluation and various evaluation techniques for readers from different disciplines. The understanding of these techniques is imperative if we wish to support analysis in the visual analytics software we develop. Currently the evaluations that are conducted and published for visual analytics software are very informal and consist mainly of comments from users or potential users. Our goal is to help researchers in visual analytics to conduct more formal user-centered evaluations. While these are time-consuming and expensive to carryout, the outcomes of these studies will have a defining impact on the field of visual analytics and help point the direction for future features and visualizations to incorporate. While many researchers view work in user-centered evaluation as a less-than-exciting area to work, the opposite is true. First of all, the goal is user-centered evaluation is to help visual analytics software developers, researchers, and designers improve their solutions and discover creative ways to better accommodate their users. Working with the users is extremely rewarding as well. While we use the term “users” in almost all situations there are a wide variety of users that all need to be accommodated. Moreover, the domains that use visual analytics are varied and expanding. Just understanding the complexities of a number of these domains is exciting. Researchers are trying out different visualizations and interactions as well. And of course, the size and variety of data are expanding rapidly. User-centered evaluation in this context is rapidly changing. There are no standard processes and metrics and thus those of us working on user-centered evaluation must be creative in our work with both the users and with the researchers and developers.« less

A novel apparatus for interocular interaction evaluation in children with and without anisometropic amblyopia.

PubMed

Lai, Xin Jie Angela; Alexander, Jack; He, Ming Guang; Yang, Zhi Kuan; Suttle, Catherine

2012-07-01

Dichoptic visual stimulation may be achieved using shutter goggles and mirror systems. These methods vary in their feasibility for use in children. This study aims to investigate the feasibility of use of a simple trial frame-based system to evaluate interactions in children. Low contrast acuity, contrast sensitivity and alignment sensitivity were measured in the non-dominant eye of 10 normally-sighted children, 14 anisometropic children without amblyopia and 14 anisometropic amblyopic children (aged 5-11 years) using goggles and a trial frame apparatus (TFA). The dominant eye was either fully or partially occluded. The difference in visual functions in the non-dominant eye between the full and partial occlusion conditions was termed the 'interaction index'. Agreement between the TFA and goggles in terms of visual functions and interactions was assessed in anisometropic children with and without amblyopia using the Bland-Altman method and t-test. Training sessions allowed subjects to become accustomed to the systems and tasks. The duration of training, the number of breaks requested by subjects and their willingness to attend further experiments were recorded in 10 subjects from each group and were compared between groups and between systems. Both Bland-Altman and t-test methods indicated acceptable agreement between the TFA and goggles in visual function and interaction measures (p > 0.05), except for contrast sensitivity measured in anisometropic children without amblyopia (p = 0.042). For all subject groups, contrast sensitivity training was significantly longer using goggles than using the TFA (p ≤ 0.001). Significantly more breaks were requested in acuity and contrast sensitivity testing, when goggles were used than when the TFA was used (p < 0.045). Anisometropic children without amblyopia showed a significantly greater willingness to attend more experiments using the TFA than using goggles (p = 0.025). The TFA may be a useful tool in studies of interactions in amblyopes, particularly in studies of children's vision. © 2012 The Authors. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.

Development and validation of a brief, descriptive Danish pain questionnaire (BDDPQ).

PubMed

Perkins, F M; Werner, M U; Persson, F; Holte, K; Jensen, T S; Kehlet, H

2004-04-01

A new pain questionnaire should be simple, be documented to have discriminative function, and be related to previously used questionnaires. Word meaning was validated by using bilingual Danish medical students and asking them to translate words taken from the Danish version of the McGill pain questionnaire into English. Evaluative word value was estimated using a visual analog scale (VAS). Discriminative function was assessed by having patients with one of six painful conditions (postherpetic neuralgia, phantom limb pain, rheumatoid arthritis, ankle fracture, appendicitis, or labor pain) complete the questionnaire. We were not able to find Danish words that were reliably back-translated to the English words 'splitting' or 'gnawing'. A simple three-word set of evaluative terms had good separation when rated on a VAS scale ('let' 17.5+/-6.5 mm; 'moderat' 42.7+/-8.6 mm; and 'staerk' 74.9+/-9.7 mm). The questionnaire was able to discriminate among the six painful conditions with 77% accuracy by just using the descriptive words. The accuracy of the questionnaire increased to 96% with the addition of evaluative terms (for pain at rest and with activity), chronicity (acute vs. chronic), and location of the pain. A Danish pain questionnaire that subjects and patients can self-administer has been developed and validated relative to the words used in the English McGill Pain questionnaire. The discriminative ability of the questionnaire among some common painful conditions has been tested and documented. The questionnaire may be of use in patient care and research.

Development of a computational model on the neural activity patterns of a visual working memory in a hierarchical feedforward Network

NASA Astrophysics Data System (ADS)

An, Soyoung; Choi, Woochul; Paik, Se-Bum

2015-11-01

Understanding the mechanism of information processing in the human brain remains a unique challenge because the nonlinear interactions between the neurons in the network are extremely complex and because controlling every relevant parameter during an experiment is difficult. Therefore, a simulation using simplified computational models may be an effective approach. In the present study, we developed a general model of neural networks that can simulate nonlinear activity patterns in the hierarchical structure of a neural network system. To test our model, we first examined whether our simulation could match the previously-observed nonlinear features of neural activity patterns. Next, we performed a psychophysics experiment for a simple visual working memory task to evaluate whether the model could predict the performance of human subjects. Our studies show that the model is capable of reproducing the relationship between memory load and performance and may contribute, in part, to our understanding of how the structure of neural circuits can determine the nonlinear neural activity patterns in the human brain.

The sensitivity of Galvanic Skin Response for assessing mental workload in Indonesia.

PubMed

Widyanti, Ari; Muslim, Khoirul; Sutalaksana, Iftikar Zahedi

2017-01-01

Objective measures have been shown to be equally sensitive in different cultures. However, these measures need special devices that are relatively expensive and need expertise to analyze the result. In Indonesia, there is a need for a sensitive and affordable mental workload measure. To evaluate the sensitivity of Galvanic Skin Response (GSR) in assessing mental workload in Indonesia. A total of 72 Indonesian students with normal visual capability. Participants were asked to work on visual memory search task with a secondary task of counting with three different levels of difficulty. GSR, Heart Rate Variability (HRV), and the NASA-TLX were administered prior to, during, and after the tasks. GSR measure was compared to NASA-TLX and HRV measures. Like the HRV, GSR showed to be sensitive in distinguishing rest and task condition significantly but not sensitive in distinguishing different levels of mental workload. In contrast, both the NASA-TLX and performance measure were sensitive in differentiating different levels of mental workload. GSR has potential as a simple, cost-effective tool for measuring mental workload in Indonesia.

Beauty is in the efficient coding of the beholder.

PubMed

Renoult, Julien P; Bovet, Jeanne; Raymond, Michel

2016-03-01

Sexual ornaments are often assumed to be indicators of mate quality. Yet it remains poorly known how certain ornaments are chosen before any coevolutionary race makes them indicative. Perceptual biases have been proposed to play this role, but known biases are mostly restricted to a specific taxon, which precludes evaluating their general importance in sexual selection. Here we identify a potentially universal perceptual bias in mate choice. We used an algorithm that models the sparseness of the activity of simple cells in the primary visual cortex (or V1) of humans when coding images of female faces. Sparseness was found positively correlated with attractiveness as rated by men and explained up to 17% of variance in attractiveness. Because V1 is adapted to process signals from natural scenes, in general, not faces specifically, our results indicate that attractiveness for female faces is influenced by a visual bias. Sparseness and more generally efficient neural coding are ubiquitous, occurring in various animals and sensory modalities, suggesting that the influence of efficient coding on mate choice can be widespread in animals.

The mere exposure effect in the domain of haptics.

PubMed

Jakesch, Martina; Carbon, Claus-Christian

2012-01-01

Zajonc showed that the attitude towards stimuli that one had been previously exposed to is more positive than towards novel stimuli. This mere exposure effect (MEE) has been tested extensively using various visual stimuli. Research on the MEE is sparse, however, for other sensory modalities. We used objects of two material categories (stone and wood) and two complexity levels (simple and complex) to test the influence of exposure frequency (F0 = novel stimuli, F2 = stimuli exposed twice, F10 = stimuli exposed ten times) under two sensory modalities (haptics only and haptics & vision). Effects of exposure frequency were found for high complex stimuli with significantly increasing liking from F0 to F2 and F10, but only for the stone category. Analysis of "Need for Touch" data showed the MEE in participants with high need for touch, which suggests different sensitivity or saturation levels of MEE. This different sensitivity or saturation levels might also reflect the effects of expertise on the haptic evaluation of objects. It seems that haptic and cross-modal MEEs are influenced by factors similar to those in the visual domain indicating a common cognitive basis.

Fluorescence-based visualization of autophagic activity predicts mouse embryo viability

NASA Astrophysics Data System (ADS)

Tsukamoto, Satoshi; Hara, Taichi; Yamamoto, Atsushi; Kito, Seiji; Minami, Naojiro; Kubota, Toshiro; Sato, Ken; Kokubo, Toshiaki

2014-03-01

Embryo quality is a critical parameter in assisted reproductive technologies. Although embryo quality can be evaluated morphologically, embryo morphology does not correlate perfectly with embryo viability. To improve this, it is important to understand which molecular mechanisms are involved in embryo quality control. Autophagy is an evolutionarily conserved catabolic process in which cytoplasmic materials sequestered by autophagosomes are degraded in lysosomes. We previously demonstrated that autophagy is highly activated after fertilization and is essential for further embryonic development. Here, we developed a simple fluorescence-based method for visualizing autophagic activity in live mouse embryos. Our method is based on imaging of the fluorescence intensity of GFP-LC3, a versatile marker for autophagy, which is microinjected into the embryos. Using this method, we show that embryonic autophagic activity declines with advancing maternal age, probably due to a decline in the activity of lysosomal hydrolases. We also demonstrate that embryonic autophagic activity is associated with the developmental viability of the embryo. Our results suggest that embryonic autophagic activity can be utilized as a novel indicator of embryo quality.

Gamma/x-ray linear pushbroom stereo for 3D cargo inspection

NASA Astrophysics Data System (ADS)

Zhu, Zhigang; Hu, Yu-Chi

2006-05-01

For evaluating the contents of trucks, containers, cargo, and passenger vehicles by a non-intrusive gamma-ray or X-ray imaging system to determine the possible presence of contraband, three-dimensional (3D) measurements could provide more information than 2D measurements. In this paper, a linear pushbroom scanning model is built for such a commonly used gamma-ray or x-ray cargo inspection system. Accurate 3D measurements of the objects inside a cargo can be obtained by using two such scanning systems with different scanning angles to construct a pushbroom stereo system. A simple but robust calibration method is proposed to find the important parameters of the linear pushbroom sensors. Then, a fast and automated stereo matching algorithm based on free-form deformable registration is developed to obtain 3D measurements of the objects under inspection. A user interface is designed for 3D visualization of the objects in interests. Experimental results of sensor calibration, stereo matching, 3D measurements and visualization of a 3D cargo container and the objects inside, are presented.

A gel-based visual immunoassay for non-instrumental detection of chloramphenicol in food samples.

PubMed

Yuan, Meng; Sheng, Wei; Zhang, Yan; Wang, Junping; Yang, Yijin; Zhang, Shuguang; Goryacheva, Irina Yu; Wang, Shuo

2012-11-02

A gel-based non-instrumental immuno-affinity assay was developed for the rapid screening of chloramphenicol (CAP) in food samples with the limit of detection (LOD) of 1 μg L(-1). The immuno-affinity test column (IATC) consisted of a test layer containing anti-CAP antibody coupled gel, and a control layer with anti-HRP antibody coupled gel. Based on the direct competitive immuno-reaction and the horseradish peroxidase enzymatic reaction, the test results could be evaluated visually. Basically, blue color development represented the negative results, while the absence of color development represented the positive results. In this study, CAP spiked samples of raw milk, pasteurized milk, UHT milk, skimmed milk powder, acacia honey, date honey, fish and shrimp were tested. Little or none sample pretreatment was required for this assay. The whole procedure was completed within 10min. In conclusion, the gel-based immuno-affinity test is a simple, rapid, and promising on-site screening method for CAP residues in food samples, with no instrumental requirement. Copyright © 2012 Elsevier B.V. All rights reserved.

Smart photonic coating as a new visualization technique of strain deformation of metal plates

NASA Astrophysics Data System (ADS)

Fudouzi, Hiroshi; Sawada, Tsutomu; Tanaka, Yoshikazu; Ario, Ichiro; Hyakutake, Tsuyoshi; Nishizaki, Itaru

2012-04-01

We will present a simple and low cost method to visualize local strain distribution in deformed aluminum plates. In this study, aluminum plates were coated with opal photonic crystal film with tunable structural color. The photonic crystal films consist of a silicone elastomer that contains an array of submicron polystyrene colloidal particles. When the aluminum sheets were stretched, the change in the spacing of the colloidal particles in the opal film alters the color of the film. This approach could be useful as a new strain gauge having a visual indicator to detect mechanical deformation.

Human area MT+ shows load-dependent activation during working memory maintenance with continuously morphing stimulation.

PubMed

Galashan, Daniela; Fehr, Thorsten; Kreiter, Andreas K; Herrmann, Manfred

2014-07-11

Initially, human area MT+ was considered a visual area solely processing motion information but further research has shown that it is also involved in various different cognitive operations, such as working memory tasks requiring motion-related information to be maintained or cognitive tasks with implied or expected motion.In the present fMRI study in humans, we focused on MT+ modulation during working memory maintenance using a dynamic shape-tracking working memory task with no motion-related working memory content. Working memory load was systematically varied using complex and simple stimulus material and parametrically increasing retention periods. Activation patterns for the difference between retention of complex and simple memorized stimuli were examined in order to preclude that the reported effects are caused by differences in retrieval. Conjunction analysis over all delay durations for the maintenance of complex versus simple stimuli demonstrated a wide-spread activation pattern. Percent signal change (PSC) in area MT+ revealed a pattern with higher values for the maintenance of complex shapes compared to the retention of a simple circle and with higher values for increasing delay durations. The present data extend previous knowledge by demonstrating that visual area MT+ presents a brain activity pattern usually found in brain regions that are actively involved in working memory maintenance.

[Multifocal visual electrophysiology in visual function evaluation].

PubMed

Peng, Shu-Ya; Chen, Jie-Min; Liu, Rui-Jue; Zhou, Shu; Liu, Dong-Mei; Xia, Wen-Tao

2013-08-01

Multifocal visual electrophysiology, consisting of multifocal electroretinography (mfERG) and multifocal visual evoked potential (mfVEP), can objectively evaluate retina function and retina-cortical conduction pathway status by stimulating many local retinal regions and obtaining each local response simultaneously. Having many advantages such as short testing time and high sensitivity, it has been widely used in clinical ophthalmology, especially in the diagnosis of retinal disease and glaucoma. It is a new objective technique in clinical forensic medicine involving visual function evaluation of ocular trauma in particular. This article summarizes the way of stimulation, the position of electrodes, the way of analysis, the visual function evaluation of mfERG and mfVEP, and discussed the value of multifocal visual electrophysiology in forensic medicine.

Outcome of cataract surgery following simple limbal epithelial transplantation for lime injury-induced limbal stem cell deficiency

PubMed Central

Nair, Dhanyasree

2015-01-01

A 19-year-old woman presented to us after being diagnosed elsewhere with right eye total limbal stem cell deficiency resulting from a lime burn. She was advised to undergo limbal stem cell transplantation, but failed to immediately do so. Two years later, she underwent cultivated limbal epithelial transplantation (CLET). As she had severe loss of vision with persisting conjunctival nodule and symblepharon 2 years following surgery, an impression of failed CLET was formed. Subsequently, simple limbal epithelial transplantation (SLET) was performed. Nine months later, she developed a cataract in her right eye; the cataract was extracted and posterior chamber intraocular lens implanted. The unaided visual acuity improved from light perception at presentation to 20/60 at 1-week postoperatively. At 5 months follow-up, the patient continued to maintain 20/60 visual acuity in her right eye. This case describes the outcome of cataract surgery following SLET, emphasising the need to perform cataract surgery in complicated cataracts for a better visual prognosis. PMID:26698204

Stimulus novelty, task relevance and the visual evoked potential in man

NASA Technical Reports Server (NTRS)

Courchesne, E.; Hillyard, S. A.; Galambos, R.

1975-01-01

The effect of task relevance on P3 (waveform of human evoked potential) waves and the methodologies used to deal with them are outlined. Visual evoked potentials (VEPs) were recorded from normal adult subjects performing in a visual discrimination task. Subjects counted the number of presentations of the numeral 4 which was interposed rarely and randomly within a sequence of tachistoscopically flashed background stimuli. Intrusive, task-irrelevant (not counted) stimuli were also interspersed rarely and randomly in the sequence of 2s; these stimuli were of two types: simples, which were easily recognizable, and novels, which were completely unrecognizable. It was found that the simples and the counted 4s evoked posteriorly distributed P3 waves while the irrelevant novels evoked large, frontally distributed P3 waves. These large, frontal P3 waves to novels were also found to be preceded by large N2 waves. These findings indicate that the P3 wave is not a unitary phenomenon but should be considered in terms of a family of waves, differing in their brain generators and in their psychological correlates.

The Flushtration Count Illusion: Attribute substitution tricks our interpretation of a simple visual event sequence.

PubMed

Thomas, Cyril; Didierjean, André; Kuhn, Gustav

2018-04-17

When faced with a difficult question, people sometimes work out an answer to a related, easier question without realizing that a substitution has taken place (e.g., Kahneman, 2011, Thinking, fast and slow. New York, Farrar, Strauss, Giroux). In two experiments, we investigated whether this attribute substitution effect can also affect the interpretation of a simple visual event sequence. We used a magic trick called the 'Flushtration Count Illusion', which involves a technique used by magicians to give the illusion of having seen multiple cards with identical backs, when in fact only the back of one card (the bottom card) is repeatedly shown. In Experiment 1, we demonstrated that most participants are susceptible to the illusion, even if they have the visual and analytical reasoning capacity to correctly process the sequence. In Experiment 2, we demonstrated that participants construct a biased and simplified representation of the Flushtration Count by substituting some attributes of the event sequence. We discussed of the psychological processes underlying this attribute substitution effect. © 2018 The British Psychological Society.

Casual Video Games as Training Tools for Attentional Processes in Everyday Life.

PubMed

Stroud, Michael J; Whitbourne, Susan Krauss

2015-11-01

Three experiments examined the attentional components of the popular match-3 casual video game, Bejeweled Blitz (BJB). Attentionally demanding, BJB is highly popular among adults, particularly those in middle and later adulthood. In experiment 1, 54 older adults (Mage = 70.57) and 33 younger adults (Mage = 19.82) played 20 rounds of BJB, and completed online tasks measuring reaction time, simple visual search, and conjunction visual search. Prior experience significantly predicted BJB scores for younger adults, but for older adults, both prior experience and simple visual search task scores predicted BJB performance. Experiment 2 tested whether BJB practice alone would result in a carryover benefit to a visual search task in a sample of 58 young adults (Mage = 19.57) who completed 0, 10, or 30 rounds of BJB followed by a BJB-like visual search task with targets present or absent. Reaction times were significantly faster for participants who completed 30 but not 10 rounds of BJB compared with the search task only. This benefit was evident when targets were both present and absent, suggesting that playing BJB improves not only target detection, but also the ability to quit search effectively. Experiment 3 tested whether the attentional benefit in experiment 2 would apply to non-BJB stimuli. The results revealed a similar numerical but not significant trend. Taken together, the findings suggest there are benefits of casual video game playing to attention and relevant everyday skills, and that these games may have potential value as training tools.

Planning in sentence production: Evidence for the phrase as a default planning scope

PubMed Central

Martin, Randi C.; Crowther, Jason E.; Knight, Meredith; Tamborello, Franklin P.; Yang, Chin-Lung

2010-01-01

Controversy remains as to the scope of advanced planning in language production. Smith and Wheeldon (1999) found significantly longer onset latencies when subjects described moving picture displays by producing sentences beginning with a complex noun phrase than for matched sentences beginning with a simple noun phrase. While these findings are consistent with a phrasal scope of planning, they might also be explained on the basis of: 1) greater retrieval fluency for the second content word in the simple initial noun phrase sentences and 2) visual grouping factors. In Experiments 1 and 2, retrieval fluency for the second content word was equated for the complex and simple initial noun phrase conditions. Experiments 3 and 4 addressed the visual grouping hypothesis by using stationary displays and by comparing onset latencies for the same display for sentence and list productions. Longer onset latencies for the sentences beginning with a complex noun phrase were obtained in all experiments, supporting the phrasal scope of planning hypothesis. The results indicate that in speech, as in other motor production domains, planning occurs beyond the minimal production unit. PMID:20501338

Contrast discrimination, non-uniform patterns and change blindness.

PubMed Central

Scott-Brown, K C; Orbach, H S

1998-01-01

Change blindness--our inability to detect large changes in natural scenes when saccades, blinks and other transients interrupt visual input--seems to contradict psychophysical evidence for our exquisite sensitivity to contrast changes. Can the type of effects described as 'change blindness' be observed with simple, multi-element stimuli, amenable to psychophysical analysis? Such stimuli, composed of five mixed contrast elements, elicited a striking increase in contrast increment thresholds compared to those for an isolated element. Cue presentation prior to the stimulus substantially reduced thresholds, as for change blindness with natural scenes. On one hand, explanations for change blindness based on abstract and sketchy representations in short-term visual memory seem inappropriate for this low-level image property of contrast where there is ample evidence for exquisite performance on memory tasks. On the other hand, the highly increased thresholds for mixed contrast elements, and the decreased thresholds when a cue is present, argue against any simple early attentional or sensory explanation for change blindness. Thus, psychophysical results for very simple patterns cannot straightforwardly predict results even for the slightly more complicated patterns studied here. PMID:9872004

Technical Advances in Intracellular Detection Using Immuno-Gold Particles: Simple Cryofixation with Metal Contact Quick Freezing.

PubMed

Song, Chihong; Lee, Ju Huck; Jun, Sangmi; Chung, Jeong Min; Hyun, Jaekyung; Jung, Hyun Suk

2016-05-01

The preparation of biological specimens using cryofixation techniques ensures excellent visibility of intracellular structures and preserves the antigenic sites of subcellular molecules. Hence, cryofixation is an effective method of preparing samples for analyses using antibodies conjugated to gold nanoparticles that are designed to detect the localization of specific target molecules within cells. However, cryofixation cannot be utilized easily because it requires expensive equipment and skilled technologists, resulting in a high level of expense for researchers. Here, we describe a simple technical approach to cryofixation that uses metal contact quick freezing followed by a modified freeze substitution technique and immuno-gold labeling electron microscopy. Micrograph images of cells prepared using this modified cryofixation method demonstrated its superiority over chemical fixation for high contrast visualization of the morphologies of cellular components and preservation of antigenicity for immuno-gold labeling. This report provides valuable technical information related to the advancement of metal contact quick freezing techniques, which can be used to visualize biomedical events of interest in an easy, simple, and rapid manner.

38 CFR 4.75 - General considerations for evaluating visual impairment.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-connected visual impairment of only one eye. Subject to the provisions of 38 CFR 3.383(a), if visual impairment of only one eye is service-connected, the visual acuity of the other eye will be considered to be... visual impairment of one eye. The evaluation for visual impairment of one eye must not exceed 30 percent...

38 CFR 4.75 - General considerations for evaluating visual impairment.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-connected visual impairment of only one eye. Subject to the provisions of 38 CFR 3.383(a), if visual impairment of only one eye is service-connected, the visual acuity of the other eye will be considered to be... visual impairment of one eye. The evaluation for visual impairment of one eye must not exceed 30 percent...

The applicability of WHO-NCTB in Korea.

PubMed

Kang, S K

2000-10-01

Neurotoxic chemical substances have been widely used in Korea since 1960. The World Health Organization-recommended Neurobehavioral Core Test Battery (WHO-NCTB) was introduced into Korea early in the 1990s and has been applied to the study of workers exposed to neurotoxic chemicals. Thirteen studies using the WHO-NCTB have been reported in Korean journals, two of which were published in English and the rest in Korean-language journals. Ten studies were reviewed to examine the influence of age, education and other factors on the WHO-NCTB in Korean workers. Pursuit Aiming, Digit Symbol, Digit Span and Benton Visual Retention test are effected by years of education, especially when years of education were less than 12. Santa Ana Dexterity test and Simple Reaction Time test were not effected. Pursuit Aiming, Santa Ana Dexterity test and Digit Symbol were effected by age, but not the Simple Reaction Time test, Benton Visual Retention test, or Digit Span. Some studies had difficulty in finding a proper reference group, because many workers exposed to neurotoxic chemicals were old and less educated than available reference groups. However, daily use of chopsticks by Koreans, especially coupled with work that requires skillful and quick hand movements, might develop psychomotor functions in exposed workers. The cultural and emotional differences between Korean and Caucasian led POMS to be applied only to two studies. In conclusion, the WHO-NCTB has been successfully applied to Korean workers for evaluating the neurobehavioral effects of individual chemicals, although age and education can be confounding factors. It was difficult to apply the WHO-NCTB to workers educated less than 12 years.

The relaxation response: reducing stress and improving cognition in healthy aging adults.

PubMed

Galvin, Jennifer A; Benson, Herbert; Deckro, Gloria R; Fricchione, Gregory L; Dusek, Jeffery A

2006-08-01

Aging adults are vulnerable to the effects of a negative emotional state. The relaxation response (RR) is a mind-body intervention that counteracts the harmful effects of stress. Previous studies with relaxation techniques have shown the non-pharmacological benefit of reducing stress and improving the memory of healthy older adults. Our pilot study evaluated whether a RR training program would decrease anxiety levels, improve attention, declarative memory performance and/or decrease salivary cortisol levels in healthy older adults. Fifteen adults participated and were randomly assigned to a RR training or control groups. Mean age was 71.3 years and mean education level was 17.9 years. Reaction time on a simple attention/psychomotor task was significantly improved (p<0.0025) with RR training, whereas there was no significant improvement on complex tasks of attention, verbal, or visual declarative memory tests. Self-reported state anxiety levels showed a marginally significant reduction (p<0.066). All subjects' salivary cortisol levels were within low-normal range and did not significantly change. Our 5-week program in highly educated, mobile, healthy, aging adults significantly improved performance on a simple attention task.

Case studies evaluating the quality of synthetic environments

NASA Astrophysics Data System (ADS)

Deisinger, Joachim; Blach, Roland; Simon, Andreas

1999-03-01

Multi wall stereo projection systems (MWSP) are an emerging display paradigm, promising a new quality in 3D-real-time interactions. Not much is known about the ergonomics of these systems. In this paper some basics of perception and approaches to improve the visual quality will be discussed and results of four experiments will be presented in order to obtain a better understanding of user interactions with existing projection technology. Due to the limited number of participants the experiments are considered as case-studies only. The first task was the estimation of absolute geometrical dimensions of simple objects. The second task was grabbing simple objects of different sizes. In order to classify MWSP, these tasks were compared to other display devices and compared to physical reality. We conducted two further experiments to compare different viewing devices for virtual reality (VR) like Head Mounted Displays (HMD), monitor, and the MWSP. For all of those experiments quantitative data was collected as a measure of interaction quality. The last two tests were supported by pre- and post questionnaires to obtain subjective judgement of the displays as well.

Age and gender are important considerations in choosing the sniffing position for laryngoscopic view.

PubMed

Park, Sung-Wook; Lee, Kang-Woo; Jang, Myung-Soo; Jung, Jun-Young; Lee, Bong-Jae; Kang, Jong-Man

2014-01-01

The sniffing position is considered to be the standard position for direct laryngoscopic viewing. This crossover study evaluated age and gender as variables in comparing the benefits of the sniffing position over simple head extension for laryngeal view during direct laryngoscopy. Laryngoscopy with a curved blade was performed on 200 anesthetized adults (100 males, 100 females) presenting for routine elective surgery. Glottic visualization was assessed by using the percentage of glottic opening (POGO) score in both simple extension and sniffing positions without the aid of the assistant or external laryngeal manipulation. Each gender group was divided into a younger group (< 50 years) and an older group (≥ 50 years). POGO scores were compared between both positions within each group. Mean (SD) POGO scores increased significantly only in younger male patients from 43% (39%) in the head extension position to 76% (30%) in the sniffing position. The sniffing position seems to be advantageous for getting a better laryngeal view during laryngoscopy for tracheal intubation in adult male patients less than 50 years old.

A Simple Configuration for Quantitative Phase Contrast Microscopy of Transmissible Samples

NASA Astrophysics Data System (ADS)

Sengupta, Chandan; Dasgupta, Koustav; Bhattacharya, K.

Phase microscopy attempts to visualize and quantify the phase distribution of samples which are otherwise invisible under microscope without the use of stains. The two principal approaches to phase microscopy are essentially those of Fourier plane modulation and interferometric techniques. Although the former, first proposed by Zernike, had been the harbinger of phase microscopy, it was the latter that allowed for quantitative evaluation of phase samples. However interferometric techniques are fraught with associated problems such as complicated setup involving mirrors and beam-splitters, the need for a matched objective in the reference arm and also the need for vibration isolation. The present work proposes a single element cube beam-splitter (CBS) interferometer combined with a microscope objective (MO) for interference microscopy. Because of the monolithic nature of the interferometer, the system is almost insensitive to vibrations and relatively simple to align. It will be shown that phase shifting properties may also be introduced by suitable and proper use of polarizing devices. Initial results showing the quantitative three dimensional phase profiles of simulated and actual biological specimens are presented.

Comparative system identification of flower tracking performance in three hawkmoth species reveals adaptations for dim light vision.

PubMed

Stöckl, Anna L; Kihlström, Klara; Chandler, Steven; Sponberg, Simon

2017-04-05

Flight control in insects is heavily dependent on vision. Thus, in dim light, the decreased reliability of visual signal detection also prompts consequences for insect flight. We have an emerging understanding of the neural mechanisms that different species employ to adapt the visual system to low light. However, much less explored are comparative analyses of how low light affects the flight behaviour of insect species, and the corresponding links between physiological adaptations and behaviour. We investigated whether the flower tracking behaviour of three hawkmoth species with different diel activity patterns revealed luminance-dependent adaptations, using a system identification approach. We found clear luminance-dependent differences in flower tracking in all three species, which were explained by a simple luminance-dependent delay model, which generalized across species. We discuss physiological and anatomical explanations for the variance in tracking responses, which could not be explained by such simple models. Differences between species could not be explained by the simple delay model. However, in several cases, they could be explained through the addition on a second model parameter, a simple scaling term, that captures the responsiveness of each species to flower movements. Thus, we demonstrate here that much of the variance in the luminance-dependent flower tracking responses of hawkmoths with different diel activity patterns can be captured by simple models of neural processing.This article is part of the themed issue 'Vision in dim light'. © 2017 The Author(s).

Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies.

PubMed

Häggström, Ida; Beattie, Bradley J; Schmidtlein, C Ross

2016-06-01

To develop and evaluate a fast and simple tool called dpetstep (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. The tool was developed in matlab using both new and previously reported modules of petstep (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). dpetstep was 8000 times faster than MC. Dynamic images from dpetstep had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dpetstep and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dpetstep images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p < 0.01). Compared to GAUSS, dpetstep images and noise properties agreed better with MC. The authors have developed a fast and easy one-stop solution for simulations of dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dpetstep to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for studies investigating these phenomena. dpetstep can be downloaded free of cost from https://github.com/CRossSchmidtlein/dPETSTEP.

Right hemispheric dominance of visual phenomena evoked by intracerebral stimulation of the human visual cortex.

PubMed

Jonas, Jacques; Frismand, Solène; Vignal, Jean-Pierre; Colnat-Coulbois, Sophie; Koessler, Laurent; Vespignani, Hervé; Rossion, Bruno; Maillard, Louis

2014-07-01

Electrical brain stimulation can provide important information about the functional organization of the human visual cortex. Here, we report the visual phenomena evoked by a large number (562) of intracerebral electrical stimulations performed at low-intensity with depth electrodes implanted in the occipito-parieto-temporal cortex of 22 epileptic patients. Focal electrical stimulation evoked primarily visual hallucinations with various complexities: simple (spot or blob), intermediary (geometric forms), or complex meaningful shapes (faces); visual illusions and impairments of visual recognition were more rarely observed. With the exception of the most posterior cortical sites, the probability of evoking a visual phenomenon was significantly higher in the right than the left hemisphere. Intermediary and complex hallucinations, illusions, and visual recognition impairments were almost exclusively evoked by stimulation in the right hemisphere. The probability of evoking a visual phenomenon decreased substantially from the occipital pole to the most anterior sites of the temporal lobe, and this decrease was more pronounced in the left hemisphere. The greater sensitivity of the right occipito-parieto-temporal regions to intracerebral electrical stimulation to evoke visual phenomena supports a predominant role of right hemispheric visual areas from perception to recognition of visual forms, regardless of visuospatial and attentional factors. Copyright © 2013 Wiley Periodicals, Inc.

SEM visualization of glycosylated surface molecules using lectin-coated microspheres

NASA Technical Reports Server (NTRS)

Duke, J.; Janer, L.; Campbell, M.

1985-01-01

There are several techniques currently used to localize glycosylated surface molecules by scanning electron microscopy (Grinnell, 1980; Molday, 1976; Linthicum and Sell, 1975; Nicolson, 1974; Lo Buglio, et al, 1972). A simple and rapid method, using a modification of Grinnell's technique is reported here. Essentially, microspheres coated with Concavalin A are used to bind to glycosylated regions of the palatal shelf epithelium and are visualized in the scanning electron microscope (SEM).

SPV: a JavaScript Signaling Pathway Visualizer.

PubMed

Calderone, Alberto; Cesareni, Gianni

2018-03-24

The visualization of molecular interactions annotated in web resources is useful to offer to users such information in a clear intuitive layout. These interactions are frequently represented as binary interactions that are laid out in free space where, different entities, cellular compartments and interaction types are hardly distinguishable. SPV (Signaling Pathway Visualizer) is a free open source JavaScript library which offers a series of pre-defined elements, compartments and interaction types meant to facilitate the representation of signaling pathways consisting of causal interactions without neglecting simple protein-protein interaction networks. freely available under Apache version 2 license; Source code: https://github.com/Sinnefa/SPV_Signaling_Pathway_Visualizer_v1.0. Language: JavaScript; Web technology: Scalable Vector Graphics; Libraries: D3.js. sinnefa@gmail.com.

[Describe and convince: visual rhetoric of cinematography in medicine].

PubMed

Panese, Francesco

2009-01-01

The tools of visualisation occupy a central place in medicine. Far from being simple accessories of glance, they literally constitute objects of medicine. Such empirical acknowledgement and epistemological position open a vast field of investigation: visual technologies of medical knowledge. This article studies the development and transformation of medical objects which have permitted to assess the role of temporality in the epistemology of medicine. It firstly examines the general problem of the relationships between cinema, animated image and medicine and secondly, the contribution of the German doctor Martin Weiser to medical cinematography as a method. Finally, a typology is sketched out organising the variety of the visual technology of movement under the perspective of the development of specific visual techniques in medicine.

A methodology for the assessment of manned flight simulator fidelity

NASA Technical Reports Server (NTRS)

Hess, Ronald A.; Malsbury, Terry N.

1989-01-01

A relatively simple analytical methodology for assessing the fidelity of manned flight simulators for specific vehicles and tasks is offered. The methodology is based upon an application of a structural model of the human pilot, including motion cue effects. In particular, predicted pilot/vehicle dynamic characteristics are obtained with and without simulator limitations. A procedure for selecting model parameters can be implemented, given a probable pilot control strategy. In analyzing a pair of piloting tasks for which flight and simulation data are available, the methodology correctly predicted the existence of simulator fidelity problems. The methodology permitted the analytical evaluation of a change in simulator characteristics and indicated that a major source of the fidelity problems was a visual time delay in the simulation.

VidCat: an image and video analysis service for personal media management

NASA Astrophysics Data System (ADS)

Begeja, Lee; Zavesky, Eric; Liu, Zhu; Gibbon, David; Gopalan, Raghuraman; Shahraray, Behzad

2013-03-01

Cloud-based storage and consumption of personal photos and videos provides increased accessibility, functionality, and satisfaction for mobile users. One cloud service frontier that is recently growing is that of personal media management. This work presents a system called VidCat that assists users in the tagging, organization, and retrieval of their personal media by faces and visual content similarity, time, and date information. Evaluations for the effectiveness of the copy detection and face recognition algorithms on standard datasets are also discussed. Finally, the system includes a set of application programming interfaces (API's) allowing content to be uploaded, analyzed, and retrieved on any client with simple HTTP-based methods as demonstrated with a prototype developed on the iOS and Android mobile platforms.

Effect of pain-free range exercise on shoulder pain and range of motion in an amateur skier.

PubMed

Yoo, Won-Gyu

2016-12-01

[Purpose] This study prescribed pain-free range exercises for a female amateur skier who complained of limitations in her shoulder range of motion, and pain caused by protective spasms; the tester evaluated the effects of such exercise on pain. [Subject and Methods] A 23-year-old female who complained of pain of 3 weeks in duration in the right glenohumoral and scapulothoracic joints was enrolled. [Results] After pain-free range exercises, the visual analog pain score was 2 and the shoulder flexion and abduction angles improved compared to the initial values. [Conclusion] Thus, this study suggests muscle-strengthening exercises within the pain-free range, rather than simple pain treatments, as therapy for acute muscle injuries in skiers.

Detection of osmotic damages in GRP boat hulls

NASA Astrophysics Data System (ADS)

Krstulović-Opara, L.; Domazet, Ž.; Garafulić, E.

2013-09-01

Infrared thermography as a tool of non-destructive testing is method enabling visualization and estimation of structural anomalies and differences in structure's topography. In presented paper problem of osmotic damage in submerged glass reinforced polymer structures is addressed. The osmotic damage can be detected by a simple humidity gauging, but for proper evaluation and estimation testing methods are restricted and hardly applicable. In this paper it is demonstrated that infrared thermography, based on estimation of heat wave propagation, can be used. Three methods are addressed; Pulsed thermography, Fast Fourier Transform and Continuous Morlet Wavelet. An additional image processing based on gradient approach is applied on all addressed methods. It is shown that the Continuous Morlet Wavelet is the most appropriate method for detection of osmotic damage.

Detection of Ballast Damage by In-Situ Vibration Measurement of Sleepers

NASA Astrophysics Data System (ADS)

Lam, H. F.; Wong, M. T.; Keefe, R. M.

2010-05-01

Ballasted track is one of the most important elements of railway transportation systems worldwide. Owing to its importance in railway safety, many monitoring and evaluation methods have been developed. Current railway track monitoring systems are comprehensive, fast and efficient in testing railway track level and alignment, rail gauge, rail corrugation, etc. However, the monitoring of ballast condition still relies very much on visual inspection and core tests. Although extensive research has been carried out in the development of non-destructive methods for ballast condition evaluation, a commonly accepted and cost-effective method is still in demand. In Hong Kong practice, if abnormal train vibration is reported by the train operator or passengers, permanent way inspectors will locate the problem area by track geometry measurement. It must be pointed out that visual inspection can only identify ballast damage on the track surface, the track geometry deficiencies and rail twists can be detected using a track gauge. Ballast damage under the sleeper loading area and the ballast shoulder, which are the main factors affecting track stability and ride quality, are extremely difficult if not impossible to be detected by visual inspection. Core test is a destructive test, which is expensive, time consuming and may be disruptive to traffic. A fast real-time ballast damage detection method that can be implemented by permanent way inspectors with simple equipment can certainly provide valuable information for engineers in assessing the safety and riding quality of ballasted track systems. The main objective of this paper is to study the feasibility in using the vibration characteristics of sleepers in quantifying the ballast condition under the sleepers, and so as to explore the possibility in developing a handy method for the detection of ballast damage based on the measured vibration of sleepers.

The window of visibility: A psychological theory of fidelity in time-sampled visual motion displays

NASA Technical Reports Server (NTRS)

Watson, A. B.; Ahumada, A. J., Jr.; Farrell, J. E.

1983-01-01

Many visual displays, such as movies and television, rely upon sampling in the time domain. The spatiotemporal frequency spectra for some simple moving images are derived and illustrations of how these spectra are altered by sampling in the time domain are provided. A simple model of the human perceiver which predicts the critical sample rate required to render sampled and continuous moving images indistinguishable is constructed. The rate is shown to depend upon the spatial and temporal acuity of the observer, and upon the velocity and spatial frequency content of the image. Several predictions of this model are tested and confirmed. The model is offered as an explanation of many of the phenomena known as apparent motion. Finally, the implications of the model for computer-generated imagery are discussed.

Edge Detection Based On the Characteristic of Primary Visual Cortex Cells

NASA Astrophysics Data System (ADS)

Zhu, M. M.; Xu, Y. L.; Ma, H. Q.

2018-01-01

Aiming at the problem that it is difficult to balance the accuracy of edge detection and anti-noise performance, and referring to the dynamic and static perceptions of the primary visual cortex (V1) cells, a V1 cell model is established to perform edge detection. A spatiotemporal filter is adopted to simulate the receptive field of V1 simple cells, the model V1 cell is obtained after integrating the responses of simple cells by half-wave rectification and normalization, Then the natural image edge is detected by using static perception of V1 cells. The simulation results show that, the V1 model can basically fit the biological data and has the universality of biology. What’s more, compared with other edge detection operators, the proposed model is more effective and has better robustness

The neural basis of precise visual short-term memory for complex recognisable objects.

PubMed

Veldsman, Michele; Mitchell, Daniel J; Cusack, Rhodri

2017-10-01

Recent evidence suggests that visual short-term memory (VSTM) capacity estimated using simple objects, such as colours and oriented bars, may not generalise well to more naturalistic stimuli. More visual detail can be stored in VSTM when complex, recognisable objects are maintained compared to simple objects. It is not yet known if it is recognisability that enhances memory precision, nor whether maintenance of recognisable objects is achieved with the same network of brain regions supporting maintenance of simple objects. We used a novel stimulus generation method to parametrically warp photographic images along a continuum, allowing separate estimation of the precision of memory representations and the number of items retained. The stimulus generation method was also designed to create unrecognisable, though perceptually matched, stimuli, to investigate the impact of recognisability on VSTM. We adapted the widely-used change detection and continuous report paradigms for use with complex, photographic images. Across three functional magnetic resonance imaging (fMRI) experiments, we demonstrated greater precision for recognisable objects in VSTM compared to unrecognisable objects. This clear behavioural advantage was not the result of recruitment of additional brain regions, or of stronger mean activity within the core network. Representational similarity analysis revealed greater variability across item repetitions in the representations of recognisable, compared to unrecognisable complex objects. We therefore propose that a richer range of neural representations support VSTM for complex recognisable objects. Copyright © 2017 Elsevier Inc. All rights reserved.

A comparative study of visual reaction time in table tennis players and healthy controls.

PubMed

Bhabhor, Mahesh K; Vidja, Kalpesh; Bhanderi, Priti; Dodhia, Shital; Kathrotia, Rajesh; Joshi, Varsha

2013-01-01

Visual reaction time is time required to response to visual stimuli. The present study was conducted to measure visual reaction time in 209 subjects, 50 table tennis (TT) players and 159 healthy controls. The visual reaction time was measured by the direct RT computerized software in healthy controls and table tennis players. Simple visual reaction time was measured. During the reaction time testing, visual stimuli were given for eighteen times and average reaction time was taken as the final reaction time. The study shows that table tennis players had faster reaction time than healthy controls. On multivariate analysis, it was found that TT players had 74.121 sec (95% CI 98.8 and 49.4 sec) faster reaction time compared to non-TT players of same age and BMI. Also playing TT has a profound influence on visual reaction time than BMI. Our study concluded that persons involved in sports are having good reaction time as compared to controls. These results support the view that playing of table tennis is beneficial to eye-hand reaction time, improve the concentration and alertness.

Aging and feature search: the effect of search area.

PubMed

Burton-Danner, K; Owsley, C; Jackson, G R

2001-01-01

The preattentive system involves the rapid parallel processing of visual information in the visual scene so that attention can be directed to meaningful objects and locations in the environment. This study used the feature search methodology to examine whether there are aging-related deficits in parallel-processing capabilities when older adults are required to visually search a large area of the visual field. Like young subjects, older subjects displayed flat, near-zero slopes for the Reaction Time x Set Size function when searching over a broad area (30 degrees radius) of the visual field, implying parallel processing of the visual display. These same older subjects exhibited impairment in another task, also dependent on parallel processing, performed over the same broad field area; this task, called the useful field of view test, has more complex task demands. Results imply that aging-related breakdowns of parallel processing over a large visual field area are not likely to emerge when required responses are simple, there is only one task to perform, and there is no limitation on visual inspection time.

Development of a Rapid, Simple Method for Detecting Naegleria fowleri Visually in Water Samples by Loop-Mediated Isothermal Amplification (LAMP)

PubMed Central

Mahittikorn, Aongart; Mori, Hirotake; Popruk, Supaluk; Roobthaisong, Amonrattana; Sutthikornchai, Chantira; Koompapong, Khuanchai; Siri, Sukhontha; Sukthana, Yaowalark; Nacapunchai, Duangporn

2015-01-01

Naegleria fowleri is the causative agent of the fatal disease primary amebic meningoencephalitis. Detection of N. fowleri using conventional culture and biochemical-based assays is time-consuming and laborious, while molecular techniques, such as PCR, require laboratory skills and expensive equipment. We developed and evaluated a novel loop-mediated isothermal amplification (LAMP) assay targeting the virulence-related gene for N. fowleri. Time to results is about 90 min and amplification products were easily detected visually using hydroxy naphthol blue. The LAMP was highly specific after testing against related microorganisms and able to detect one trophozoite, as determined with spiked water and cerebrospinal fluid samples. The assay was then evaluated with a set of 80 water samples collected during the flooding crisis in Thailand in 2011, and 30 natural water samples from border areas of northern, eastern, western, and southern Thailand. N. fowleri was detected in 13 and 10 samples using LAMP and PCR, respectively, with a Kappa coefficient of 0.855. To the best of our knowledge, this is the first report of a LAMP assay for N. fowleri. Due to its simplicity, speed, and high sensitivity, the LAMP method described here might be useful for quickly detecting and diagnosing N. fowleri in water and clinical samples, particularly in resource-poor settings. PMID:25822175

Development of a rapid, simple method for detecting Naegleria fowleri visually in water samples by loop-mediated isothermal amplification (LAMP).

PubMed

Mahittikorn, Aongart; Mori, Hirotake; Popruk, Supaluk; Roobthaisong, Amonrattana; Sutthikornchai, Chantira; Koompapong, Khuanchai; Siri, Sukhontha; Sukthana, Yaowalark; Nacapunchai, Duangporn

2015-01-01

Naegleria fowleri is the causative agent of the fatal disease primary amebic meningoencephalitis. Detection of N. fowleri using conventional culture and biochemical-based assays is time-consuming and laborious, while molecular techniques, such as PCR, require laboratory skills and expensive equipment. We developed and evaluated a novel loop-mediated isothermal amplification (LAMP) assay targeting the virulence-related gene for N. fowleri. Time to results is about 90 min and amplification products were easily detected visually using hydroxy naphthol blue. The LAMP was highly specific after testing against related microorganisms and able to detect one trophozoite, as determined with spiked water and cerebrospinal fluid samples. The assay was then evaluated with a set of 80 water samples collected during the flooding crisis in Thailand in 2011, and 30 natural water samples from border areas of northern, eastern, western, and southern Thailand. N. fowleri was detected in 13 and 10 samples using LAMP and PCR, respectively, with a Kappa coefficient of 0.855. To the best of our knowledge, this is the first report of a LAMP assay for N. fowleri. Due to its simplicity, speed, and high sensitivity, the LAMP method described here might be useful for quickly detecting and diagnosing N. fowleri in water and clinical samples, particularly in resource-poor settings.

Development of a rapid and visual nucleotide detection method for a Chinese epidemic strain of Orientia tsutsugamushi based on recombinase polymerase amplification assay and lateral flow test.

PubMed

Qi, Yong; Yin, Qiong; Shao, Yinxiu; Cao, Min; Li, Suqin; Chen, Hongxia; Shen, Wanpeng; Rao, Jixian; Li, Jiameng; Li, Xiaoling; Sun, Yu; Lin, Yu; Deng, Yi; Zeng, Wenwen; Zheng, Shulong; Liu, Suyun; Li, Yuexi

2018-05-01

Orientia tsutsugamushi is an obligate intracellular pathogen that causes scrub typhus. Diagnosing scrub typhus remains a challenge, and a sensitive, specific, simple, and rapid diagnostic test is still needed. A recombinase polymerase amplification (RPA) assay combined with a lateral flow (LF) test targeting the 56-kDa gene of a Karp-like strain of O. tsutsugamushi was developed and optimized. The detection limits, sensitivity, specificity, and simulative clinical performance were evaluated. Primers and probe were screened to establish the RPA assay, and the reaction conditions were optimized. The detection limit was 10 copies/reaction in detecting plasmid DNA and 12 copies/reaction in detecting genomic DNA. The RPA-LF method could differentiate O. tsutsugamushi from other phylogenetically related bacteria. The sensitivity was 100% and specificity was over 90%, when evaluated using infected animal samples or simulative clinical samples. Furthermore, the method was completed in 20min at 37°C followed by a 3-5min incubation at room temperature for the development of an immunochromatographic strip, and the results could be determined visually. This method is promising for wide-ranging use in basic medical units considering that it requires minimal instruments and infrastructure and is highly time-efficient, sensitive, and specific for diagnosing scrub typhus. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Visualizing common operating picture of critical infrastructure

NASA Astrophysics Data System (ADS)

Rummukainen, Lauri; Oksama, Lauri; Timonen, Jussi; Vankka, Jouko

2014-05-01

This paper presents a solution for visualizing the common operating picture (COP) of the critical infrastructure (CI). The purpose is to improve the situational awareness (SA) of the strategic-level actor and the source system operator in order to support decision making. The information is obtained through the Situational Awareness of Critical Infrastructure and Networks (SACIN) framework. The system consists of an agent-based solution for gathering, storing, and analyzing the information, and a user interface (UI) is presented in this paper. The UI consists of multiple views visualizing information from the CI in different ways. Different CI actors are categorized in 11 separate sectors, and events are used to present meaningful incidents. Past and current states, together with geographical distribution and logical dependencies, are presented to the user. The current states are visualized as segmented circles to represent event categories. Geographical distribution of assets is displayed with a well-known map tool. Logical dependencies are presented in a simple directed graph, and users also have a timeline to review past events. The objective of the UI is to provide an easily understandable overview of the CI status. Therefore, testing methods, such as a walkthrough, an informal walkthrough, and the Situation Awareness Global Assessment Technique (SAGAT), were used in the evaluation of the UI. Results showed that users were able to obtain an understanding of the current state of CI, and the usability of the UI was rated as good. In particular, the designated display for the CI overview and the timeline were found to be efficient.

The role of pulvinar in the transmission of information in the visual hierarchy.

PubMed

Cortes, Nelson; van Vreeswijk, Carl

2012-01-01

VISUAL RECEPTIVE FIELD (RF) ATTRIBUTES IN VISUAL CORTEX OF PRIMATES HAVE BEEN EXPLAINED MAINLY FROM CORTICAL CONNECTIONS: visual RFs progress from simple to complex through cortico-cortical pathways from lower to higher levels in the visual hierarchy. This feedforward flow of information is paired with top-down processes through the feedback pathway. Although the hierarchical organization explains the spatial properties of RFs, is unclear how a non-linear transmission of activity through the visual hierarchy can yield smooth contrast response functions in all level of the hierarchy. Depending on the gain, non-linear transfer functions create either a bimodal response to contrast, or no contrast dependence of the response in the highest level of the hierarchy. One possible mechanism to regulate this transmission of visual contrast information from low to high level involves an external component that shortcuts the flow of information through the hierarchy. A candidate for this shortcut is the Pulvinar nucleus of the thalamus. To investigate representation of stimulus contrast a hierarchical model network of ten cortical areas is examined. In each level of the network, the activity from the previous layer is integrated and then non-linearly transmitted to the next level. The arrangement of interactions creates a gradient from simple to complex RFs of increasing size as one moves from lower to higher cortical levels. The visual input is modeled as a Gaussian random input, whose width codes for the contrast. This input is applied to the first area. The output activity ratio among different contrast values is analyzed for the last level to observe sensitivity to a contrast and contrast invariant tuning. For a purely cortical system, the output of the last area can be approximately contrast invariant, but the sensitivity to contrast is poor. To account for an alternative visual processing pathway, non-reciprocal connections from and to a parallel pulvinar like structure of nine areas is coupled to the system. Compared to the pure feedforward model, cortico-pulvino-cortical output presents much more sensitivity to contrast and has a similar level of contrast invariance of the tuning.

The Role of Pulvinar in the Transmission of Information in the Visual Hierarchy

PubMed Central

Cortes, Nelson; van Vreeswijk, Carl

2012-01-01

Visual receptive field (RF) attributes in visual cortex of primates have been explained mainly from cortical connections: visual RFs progress from simple to complex through cortico-cortical pathways from lower to higher levels in the visual hierarchy. This feedforward flow of information is paired with top-down processes through the feedback pathway. Although the hierarchical organization explains the spatial properties of RFs, is unclear how a non-linear transmission of activity through the visual hierarchy can yield smooth contrast response functions in all level of the hierarchy. Depending on the gain, non-linear transfer functions create either a bimodal response to contrast, or no contrast dependence of the response in the highest level of the hierarchy. One possible mechanism to regulate this transmission of visual contrast information from low to high level involves an external component that shortcuts the flow of information through the hierarchy. A candidate for this shortcut is the Pulvinar nucleus of the thalamus. To investigate representation of stimulus contrast a hierarchical model network of ten cortical areas is examined. In each level of the network, the activity from the previous layer is integrated and then non-linearly transmitted to the next level. The arrangement of interactions creates a gradient from simple to complex RFs of increasing size as one moves from lower to higher cortical levels. The visual input is modeled as a Gaussian random input, whose width codes for the contrast. This input is applied to the first area. The output activity ratio among different contrast values is analyzed for the last level to observe sensitivity to a contrast and contrast invariant tuning. For a purely cortical system, the output of the last area can be approximately contrast invariant, but the sensitivity to contrast is poor. To account for an alternative visual processing pathway, non-reciprocal connections from and to a parallel pulvinar like structure of nine areas is coupled to the system. Compared to the pure feedforward model, cortico-pulvino-cortical output presents much more sensitivity to contrast and has a similar level of contrast invariance of the tuning. PMID:22654750

[Fundus autofluorescence. Has it a place in the management of diabetic macular edema?

PubMed

Zbiba, W; Baba, A; Bouayed, E; Daldoul, A

2016-11-01

Analyze the characteristics of fundus autofluorescence of diabetic macular edema and study the association between these characteristics and visual function. Our study included 18 patients (28 eyes) with clinically significant diabetic macular edema. All patients had a complete eye examination with a fundus autofluorescence imaging and optical coherence tomography. The central macular thickness and central macular volume were measured. The integrity of the inner segment-outer segment junction and the integrity of the external limiting membrane were also evaluated in the same area. Among the 28 eyes studied, 8 had normal autofluorescence. The remaining 20 eyes had abnormal autofluorescence: a hyper-cystoid autofluorescence in 5 eyes (25%), hyper-spot autofluorescence in 8 eyes (40%), and hypo-irregular autofluorescence in 5 eyes (25%). Best corrected visual acuity was significantly better in patients with normal autofluorescence and those with hyper-cystoid autofluorescence. There was no significant difference in central macular thickness (P=0.186) and central macular volume (P=0.191) between the four groups. The autofluorescence is a simple, fast, and non-invasive technique for the study of diabetic macular edema with good correlation to the visual function as well as to the extent of damage to the retina. It is, therefore, a possible alternative to other invasive imaging techniques in particular in the long term monitoring of diabetic macular edema. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Evaluation of four novel isothermal amplification assays towards simple and rapid genotyping of chloroquine resistant Plasmodium falciparum.

PubMed

Chahar, Madhvi; Anvikar, Anup; Dixit, Rajnikant; Valecha, Neena

2018-07-01

Loop mediated isothermal amplification (LAMP) assay is sensitive, prompt, high throughput and field deployable technique for nucleic acid amplification under isothermal conditions. In this study, we have developed and optimized four different visualization methods of loop-mediated isothermal amplification (LAMP) assay to detect Pfcrt K76T mutants of P. falciparum and compared their important features for one-pot in-field applications. Even though all the four tested LAMP methods could successfully detect K76T mutants of P. falciparum, however considering the time, safety, sensitivity, cost and simplicity, the malachite green and HNB based methods were found more efficient. Among four different visual dyes uses to detect LAMP products accurately, hydroxynaphthol blue and malachite green could produce long stable color change and brightness in a close tube-based approach to prevent cross-contamination risk. Our results indicated that the LAMP offers an interesting novel and convenient best method for the rapid, sensitive, cost-effective, and fairly user friendly tool for detection of K76T mutants of P. falciparum and therefore presents an alternative to PCR-based assays. Based on our comparative analysis, better field based LAMP visualization method can be chosen easily for the monitoring of other important drug targets (Kelch13 propeller region). Copyright © 2018 Elsevier Inc. All rights reserved.

Application of an in vitro DNA protection assay to visualize stress mediation properties of the Dps protein.

PubMed

Karas, Vlad O; Westerlaken, Ilja; Meyer, Anne S

2013-05-31

Oxidative stress is an unavoidable byproduct of aerobic life. Molecular oxygen is essential for terrestrial metabolism, but it also takes part in many damaging reactions within living organisms. The combination of aerobic metabolism and iron, which is another vital compound for life, is enough to produce radicals through Fenton chemistry and degrade cellular components. DNA degradation is arguably the most damaging process involving intracellular radicals, as DNA repair is far from trivial. The assay presented in this article offers a quantitative technique to measure and visualize the effect of molecules and enzymes on radical-mediated DNA damage. The DNA protection assay is a simple, quick, and robust tool for the in vitro characterization of the protective properties of proteins or chemicals. It involves exposing DNA to a damaging oxidative reaction and adding varying concentrations of the compound of interest. The reduction or increase of DNA damage as a function of compound concentration is then visualized using gel electrophoresis. In this article we demonstrate the technique of the DNA protection assay by measuring the protective properties of the DNA-binding protein from starved cells (Dps). Dps is a mini-ferritin that is utilized by more than 300 bacterial species to powerfully combat environmental stressors. Here we present the Dps purification protocol and the optimized assay conditions for evaluating DNA protection by Dps.

Replicating receptive fields of simple and complex cells in primary visual cortex in a neuronal network model with temporal and population sparseness and reliability.

PubMed

Tanaka, Takuma; Aoyagi, Toshio; Kaneko, Takeshi

2012-10-01

We propose a new principle for replicating receptive field properties of neurons in the primary visual cortex. We derive a learning rule for a feedforward network, which maintains a low firing rate for the output neurons (resulting in temporal sparseness) and allows only a small subset of the neurons in the network to fire at any given time (resulting in population sparseness). Our learning rule also sets the firing rates of the output neurons at each time step to near-maximum or near-minimum levels, resulting in neuronal reliability. The learning rule is simple enough to be written in spatially and temporally local forms. After the learning stage is performed using input image patches of natural scenes, output neurons in the model network are found to exhibit simple-cell-like receptive field properties. When the output of these simple-cell-like neurons are input to another model layer using the same learning rule, the second-layer output neurons after learning become less sensitive to the phase of gratings than the simple-cell-like input neurons. In particular, some of the second-layer output neurons become completely phase invariant, owing to the convergence of the connections from first-layer neurons with similar orientation selectivity to second-layer neurons in the model network. We examine the parameter dependencies of the receptive field properties of the model neurons after learning and discuss their biological implications. We also show that the localized learning rule is consistent with experimental results concerning neuronal plasticity and can replicate the receptive fields of simple and complex cells.

Snoring intensity after a first session of soft palate radiofrequency: predictive value of the final result.

PubMed

Blumen, Marc Bernard; Vezina, Jean Philippe; Bequignon, Emilie; Chabolle, Frederic

2013-06-01

To determine whether snoring sound intensity measured after a first soft palate radiofrequency (RF) session for simple snoring helps predict the final result of the treatment. Observational retrospective study. We conducted a retrospective review of 105 subjects presenting with simple snoring or mild sleep apnea. All patients underwent two to three sessions of RF-assisted stiffening of the soft palate. In addition, uvulectomy was performed in case of a long uvula, and two paramedian trenches were created in the presence of palatal webbing. Snoring sound intensity was evaluated by the bed partner after each session. Eighty-six men and 19 women were included in the study. Mean age was 51.7 ± 9.8 years, and mean body mass index was 24.7 ± 4.4 kg/m(2) . The mean apnea/hypopnea index was 6.6 ± 4.2/h. The mean snoring sound intensity, as evaluated on a 10-cm visual analog scale (VAS), decreased from 8.2 ± 1.5 to 3.5 ± 2.2 after all sessions (P < .0001). A score of 3 was determined as being a score that satisfied the bed partner. Two groups were formed according to the final snoring sound intensity, using 3 as a threshold. Both groups had similar preoperative characteristics, but the snoring sound intensity was significantly lower after the first session in the group with final score <3 (P = .01). Similarly, a VAS score >7 after the first session was associated with a final score <3 in 30% of the cases. Snoring sound intensity after the first RF session helps predict the final outcome of RF-assisted stiffening of the soft palate for simple snoring. Copyright © 2012 The American Laryngological, Rhinological and Otological Society, Inc.

Evaluation of Two Lyophilized Molecular Assays to Rapidly Detect Foot-and-Mouth Disease Virus Directly from Clinical Samples in Field Settings.

PubMed

Howson, E L A; Armson, B; Madi, M; Kasanga, C J; Kandusi, S; Sallu, R; Chepkwony, E; Siddle, A; Martin, P; Wood, J; Mioulet, V; King, D P; Lembo, T; Cleaveland, S; Fowler, V L

2017-06-01

Accurate, timely diagnosis is essential for the control, monitoring and eradication of foot-and-mouth disease (FMD). Clinical samples from suspect cases are normally tested at reference laboratories. However, transport of samples to these centralized facilities can be a lengthy process that can impose delays on critical decision making. These concerns have motivated work to evaluate simple-to-use technologies, including molecular-based diagnostic platforms, that can be deployed closer to suspect cases of FMD. In this context, FMD virus (FMDV)-specific reverse transcription loop-mediated isothermal amplification (RT-LAMP) and real-time RT-PCR (rRT-PCR) assays, compatible with simple sample preparation methods and in situ visualization, have been developed which share equivalent analytical sensitivity with laboratory-based rRT-PCR. However, the lack of robust 'ready-to-use kits' that utilize stabilized reagents limits the deployment of these tests into field settings. To address this gap, this study describes the performance of lyophilized rRT-PCR and RT-LAMP assays to detect FMDV. Both of these assays are compatible with the use of fluorescence to monitor amplification in real-time, and for the RT-LAMP assays end point detection could also be achieved using molecular lateral flow devices. Lyophilization of reagents did not adversely affect the performance of the assays. Importantly, when these assays were deployed into challenging laboratory and field settings within East Africa they proved to be reliable in their ability to detect FMDV in a range of clinical samples from acutely infected as well as convalescent cattle. These data support the use of highly sensitive molecular assays into field settings for simple and rapid detection of FMDV. © 2015 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

A simple and reliable health monitoring system for shoulder health: proposal.

PubMed

Liu, Shuo-Fang; Lee, Yann-Long

2014-02-26

The current health care system is complex and inefficient. A simple and reliable health monitoring system that can help patients perform medical self-diagnosis is seldom readily available. Because the medical system is vast and complex, it has hampered or delayed patients in seeking medical advice or treatment in a timely manner, which may potentially affect the patient's chances of recovery, especially those with severe sicknesses such as cancer, and heart disease. The purpose of this paper is to propose a methodology in designing a simple, low cost, Internet-based health-screening platform. This health-screening platform will enable patients to perform medical self-diagnosis over the Internet. Historical data has shown the importance of early detection to ensure patients receive proper treatment and speedy recovery. The platform is designed with special emphasis on the user interface. Standard Web-based user-interface design is adopted so the user feels ease to operate in a familiar Web environment. In addition, graphics such as charts and graphs are used generously to help users visualize and understand the result of the diagnostic. The system is developed using hypertext preprocessor (PHP) programming language. One important feature of this system platform is that it is built to be a stand-alone platform, which tends to have better user privacy security. The prototype system platform was developed by the National Cheng Kung University Ergonomic and Design Laboratory. The completed prototype of this system platform was submitted to the Taiwan Medical Institute for evaluation. The evaluation of 120 participants showed that this platform system is a highly effective tool in health-screening applications, and has great potential for improving the medical care quality for the general public.

Radiotherapy volume delineation using dynamic [18F]-FDG PET/CT imaging in patients with oropharyngeal cancer: a pilot study.

PubMed

Silvoniemi, Antti; Din, Mueez U; Suilamo, Sami; Shepherd, Tony; Minn, Heikki

2016-11-01

Delineation of gross tumour volume in 3D is a critical step in the radiotherapy (RT) treatment planning for oropharyngeal cancer (OPC). Static [ 18 F]-FDG PET/CT imaging has been suggested as a method to improve the reproducibility of tumour delineation, but it suffers from low specificity. We undertook this pilot study in which dynamic features in time-activity curves (TACs) of [ 18 F]-FDG PET/CT images were applied to help the discrimination of tumour from inflammation and adjacent normal tissue. Five patients with OPC underwent dynamic [ 18 F]-FDG PET/CT imaging in treatment position. Voxel-by-voxel analysis was performed to evaluate seven dynamic features developed with the knowledge of differences in glucose metabolism in different tissue types and visual inspection of TACs. The Gaussian mixture model and K-means algorithms were used to evaluate the performance of the dynamic features in discriminating tumour voxels compared to the performance of standardized uptake values obtained from static imaging. Some dynamic features showed a trend towards discrimination of different metabolic areas but lack of consistency means that clinical application is not recommended based on these results alone. Impact of inflammatory tissue remains a problem for volume delineation in RT of OPC, but a simple dynamic imaging protocol proved practicable and enabled simple data analysis techniques that show promise for complementing the information in static uptake values.

Visual illusions and ethnocentrism: exemplars for teaching cross-cultural concepts.

PubMed

Keith, Kenneth D

2012-05-01

This article discusses the origins of cross-cultural interest in two concepts fundamental to psychology students' views of the world: simple visual illusions and ethnocentrism. Although students encounter these ideas in introductory psychology, textbooks rarely describe the nature or origin of cross-cultural knowledge about them. The article presents a brief account of the history of these concepts and relates them to contemporary notions of psychology and culture. Using visual perception and ethnocentrism as examples, the article suggests the importance of teaching that different people see the world in different ways and the role of that lesson in a future demanding increased cross-cultural understanding.

A CAI System for Visually Impaired Children to Improve Abilities of Orientation and Mobility

NASA Astrophysics Data System (ADS)

Yoneda, Takahiro; Kudo, Hiroaki; Minagawa, Hiroki; Ohnishi, Noboru; Matsubara, Shizuya

Some visually impaired children have difficulty in simple locomotion, and need orientation and mobility training. We developed a computer assisted instruction system which assists this training. A user realizes a task given by a tactile map and synthesized speech. The user walks around a room according to the task. The system gives the gap of walk path from its target path via both auditory and tactile feedback after the end of a task. Then the user can understand how well the user walked. We describe the detail of the proposed system and task, and the experimental result with three visually impaired children.

The clinical use of dynamic posturography in the elderly.

PubMed

Shepard, N T

1989-12-01

We provide an overview of the clinical uses of dynamic posturography. Although the equipment described to perform this testing is expensive, the concepts, especially those for sensory organization, can be applied for +20.00. To apply the six sensory organization conditions, one merely needs some way to disrupt proprioceptive information by maintaining ankle angle and providing for visual conflict stimuli. We found that proprioceptive information can be disrupted easily by asking the patient to stand on a thick (4-inch) dense piece of foam rubber like that used in cushions for furniture. Visual stabilization conflict can be provided by having the patient wear a 19- to 20-inch Japanese lantern with a head-mounting system in the center so that the patient's movements do not reflect themselves in relative movements to the visual environment. With use of these two simple tools, the six sensory organization tests can be approximated in a clinical situation in a short time and can provide some relative information about a patient's postural control capabilities. With minor additional work, a quantitative measure of output that gives indications of the amount of anterior-posterior sway also can be provided. For elderly patients with a variety of problems ranging from general unsteadiness to frank vertigo, the risk of falling can be devastating, and it is important to provide a thorough investigation of the total balance system. The systematic investigation, qualitatively or quantitatively, of integration of sensory input and motor outputs provides a dimension that typically has been lacking in the routine "dizzy patient workup" for all ages but especially for elderly patients. Therefore, the application of the postural maintenance theory with the above-described procedures or variations in these procedures appears to have a great deal of clinical relevance in the evaluation of patients with gait and balance disorders. These types of evaluations represent an adjunct or addition to the evaluation of the vestibular system and the vestibulo-ocular reflexes and by no means should be considered a substitute for that traditional evaluation. It is the combination of information that can provide the clinician with a more global picture of the entire balance system and its functional capabilities.

AppEEARS: A Simple Tool that Eases Complex Data Integration and Visualization Challenges for Users

NASA Astrophysics Data System (ADS)

Maiersperger, T.

2017-12-01

The Application for Extracting and Exploring Analysis-Ready Samples (AppEEARS) offers a simple and efficient way to perform discovery, processing, visualization, and acquisition across large quantities and varieties of Earth science data. AppEEARS brings significant value to a very broad array of user communities by 1) significantly reducing data volumes, at-archive, based on user-defined space-time-variable subsets, 2) promoting interoperability across a wide variety of datasets via format and coordinate reference system harmonization, 3) increasing the velocity of both data analysis and insight by providing analysis-ready data packages and by allowing interactive visual exploration of those packages, and 4) ensuring veracity by making data quality measures more apparent and usable and by providing standards-based metadata and processing provenance. Development and operation of AppEEARS is led by the National Aeronautics and Space Administration (NASA) Land Processes Distributed Active Archive Center (LP DAAC). The LP DAAC also partners with several other archives to extend the capability across a larger federation of geospatial data providers. Over one hundred datasets are currently available, covering a diversity of variables including land cover, population, elevation, vegetation indices, and land surface temperature. Many hundreds of users have already used this new web-based capability to make the complex tasks of data integration and visualization much simpler and more efficient.

Visual Receptive Field Structure of Cortical Inhibitory Neurons Revealed by Two-Photon Imaging Guided Recording

PubMed Central

Liu, Bao-hua; Li, Pingyang; Li, Ya-tang; Sun, Yujiao J.; Yanagawa, Yuchio; Obata, Kunihiko; Zhang, Li I.; Tao, Huizhong W.

2009-01-01

Synaptic inhibition plays an important role in shaping receptive field (RF) properties in the visual cortex. However, the underlying mechanisms remain not well understood, partly due to difficulties in systematically studying functional properties of cortical inhibitory neurons in vivo. Here, we established two-photon imaging guided cell-attached recordings from genetically labelled inhibitory neurons and nearby “shadowed” excitatory neurons in the primary visual cortex of adult mice. Our results revealed that in layer 2/3, the majority of excitatory neurons exhibited both On and Off spike subfields, with their spatial arrangement varying from being completely segregated to overlapped. On the other hand, most layer 4 excitatory neurons exhibited only one discernable subfield. Interestingly, no RF structure with significantly segregated On and Off subfields was observed for layer 2/3 inhibitory neurons of either the fast-spike or regular-spike type. They predominantly possessed overlapped On and Off subfields with a significantly larger size than the excitatory neurons, and exhibited much weaker orientation tuning. These results from the mouse visual cortex suggest that different from the push-pull model proposed for simple cells, layer 2/3 simple-type neurons with segregated spike On and Off subfields likely receive spatially overlapped inhibitory On and Off inputs. We propose that the phase-insensitive inhibition can enhance the spatial distinctiveness of On and Off subfields through a gain control mechanism. PMID:19710305

Agnosic vision is like peripheral vision, which is limited by crowding.

PubMed

Strappini, Francesca; Pelli, Denis G; Di Pace, Enrico; Martelli, Marialuisa

2017-04-01

Visual agnosia is a neuropsychological impairment of visual object recognition despite near-normal acuity and visual fields. A century of research has provided only a rudimentary account of the functional damage underlying this deficit. We find that the object-recognition ability of agnosic patients viewing an object directly is like that of normally-sighted observers viewing it indirectly, with peripheral vision. Thus, agnosic vision is like peripheral vision. We obtained 14 visual-object-recognition tests that are commonly used for diagnosis of visual agnosia. Our "standard" normal observer took these tests at various eccentricities in his periphery. Analyzing the published data of 32 apperceptive agnosia patients and a group of 14 posterior cortical atrophy (PCA) patients on these tests, we find that each patient's pattern of object recognition deficits is well characterized by one number, the equivalent eccentricity at which our standard observer's peripheral vision is like the central vision of the agnosic patient. In other words, each agnosic patient's equivalent eccentricity is conserved across tests. Across patients, equivalent eccentricity ranges from 4 to 40 deg, which rates severity of the visual deficit. In normal peripheral vision, the required size to perceive a simple image (e.g., an isolated letter) is limited by acuity, and that for a complex image (e.g., a face or a word) is limited by crowding. In crowding, adjacent simple objects appear unrecognizably jumbled unless their spacing exceeds the crowding distance, which grows linearly with eccentricity. Besides conservation of equivalent eccentricity across object-recognition tests, we also find conservation, from eccentricity to agnosia, of the relative susceptibility of recognition of ten visual tests. These findings show that agnosic vision is like eccentric vision. Whence crowding? Peripheral vision, strabismic amblyopia, and possibly apperceptive agnosia are all limited by crowding, making it urgent to know what drives crowding. Acuity does not (Song et al., 2014), but neural density might: neurons per deg 2 in the crowding-relevant cortical area. Copyright © 2017 Elsevier Ltd. All rights reserved.

Learning invariance from natural images inspired by observations in the primary visual cortex.

PubMed

Teichmann, Michael; Wiltschut, Jan; Hamker, Fred

2012-05-01

The human visual system has the remarkable ability to largely recognize objects invariant of their position, rotation, and scale. A good interpretation of neurobiological findings involves a computational model that simulates signal processing of the visual cortex. In part, this is likely achieved step by step from early to late areas of visual perception. While several algorithms have been proposed for learning feature detectors, only few studies at hand cover the issue of biologically plausible learning of such invariance. In this study, a set of Hebbian learning rules based on calcium dynamics and homeostatic regulations of single neurons is proposed. Their performance is verified within a simple model of the primary visual cortex to learn so-called complex cells, based on a sequence of static images. As a result, the learned complex-cell responses are largely invariant to phase and position.

Visuomotor Transformation in the Fly Gaze Stabilization System

PubMed Central

Huston, Stephen J; Krapp, Holger G

2008-01-01

For sensory signals to control an animal's behavior, they must first be transformed into a format appropriate for use by its motor systems. This fundamental problem is faced by all animals, including humans. Beyond simple reflexes, little is known about how such sensorimotor transformations take place. Here we describe how the outputs of a well-characterized population of fly visual interneurons, lobula plate tangential cells (LPTCs), are used by the animal's gaze-stabilizing neck motor system. The LPTCs respond to visual input arising from both self-rotations and translations of the fly. The neck motor system however is involved in gaze stabilization and thus mainly controls compensatory head rotations. We investigated how the neck motor system is able to selectively extract rotation information from the mixed responses of the LPTCs. We recorded extracellularly from fly neck motor neurons (NMNs) and mapped the directional preferences across their extended visual receptive fields. Our results suggest that—like the tangential cells—NMNs are tuned to panoramic retinal image shifts, or optic flow fields, which occur when the fly rotates about particular body axes. In many cases, tangential cells and motor neurons appear to be tuned to similar axes of rotation, resulting in a correlation between the coordinate systems the two neural populations employ. However, in contrast to the primarily monocular receptive fields of the tangential cells, most NMNs are sensitive to visual motion presented to either eye. This results in the NMNs being more selective for rotation than the LPTCs. Thus, the neck motor system increases its rotation selectivity by a comparatively simple mechanism: the integration of binocular visual motion information. PMID:18651791

Paediatric Refractive Errors in an Eye Clinic in Osogbo, Nigeria.

PubMed

Michaeline, Isawumi; Sheriff, Agboola; Bimbo, Ayegoro

2016-03-01

Paediatric ophthalmology is an emerging subspecialty in Nigeria and as such there is paucity of data on refractive errors in the country. This study set out to determine the pattern of refractive errors in children attending an eye clinic in South West Nigeria. A descriptive study of 180 consecutive subjects seen over a 2-year period. Presenting complaints, presenting visual acuity (PVA), age and sex were recorded. Clinical examination of the anterior and posterior segments of the eyes, extraocular muscle assessment and refraction were done. The types of refractive errors and their grades were determined. Corrected VA was obtained. Data was analysed using descriptive statistics in proportions, chi square with p value <0.05. The age range of subjects was between 3 and 16 years with mean age = 11.7 and SD = 0.51; with males making up 33.9%.The commonest presenting complaint was blurring of distant vision (40%), presenting visual acuity 6/9 (33.9%), normal vision constituted >75.0%, visual impairment20% and low vision 23.3%. Low grade spherical and cylindrical errors occurred most frequently (35.6% and 59.9% respectively). Regular astigmatism was significantly more common, P <0.001. The commonest diagnosis was simple myopic astigmatism (41.1%). Four cases of strabismus were seen. Simple spherical and cylindrical errors were the commonest types of refractive errors seen. Visual impairment and low vision occurred and could be a cause of absenteeism from school. Low-cost spectacle production or dispensing unit and health education are advocated for the prevention of visual impairment in a hospital set-up.

A framework for interactive visualization of digital medical images.

PubMed

Koehring, Andrew; Foo, Jung Leng; Miyano, Go; Lobe, Thom; Winer, Eliot

2008-10-01

The visualization of medical images obtained from scanning techniques such as computed tomography and magnetic resonance imaging is a well-researched field. However, advanced tools and methods to manipulate these data for surgical planning and other tasks have not seen widespread use among medical professionals. Radiologists have begun using more advanced visualization packages on desktop computer systems, but most physicians continue to work with basic two-dimensional grayscale images or not work directly with the data at all. In addition, new display technologies that are in use in other fields have yet to be fully applied in medicine. It is our estimation that usability is the key aspect in keeping this new technology from being more widely used by the medical community at large. Therefore, we have a software and hardware framework that not only make use of advanced visualization techniques, but also feature powerful, yet simple-to-use, interfaces. A virtual reality system was created to display volume-rendered medical models in three dimensions. It was designed to run in many configurations, from a large cluster of machines powering a multiwalled display down to a single desktop computer. An augmented reality system was also created for, literally, hands-on interaction when viewing models of medical data. Last, a desktop application was designed to provide a simple visualization tool, which can be run on nearly any computer at a user's disposal. This research is directed toward improving the capabilities of medical professionals in the tasks of preoperative planning, surgical training, diagnostic assistance, and patient education.

A Simple and Automatic Method for Locating Surgical Guide Hole

NASA Astrophysics Data System (ADS)

Li, Xun; Chen, Ming; Tang, Kai

2017-12-01

Restoration-driven surgical guides are widely used in implant surgery. This study aims to provide a simple and valid method of automatically locating surgical guide hole, which can reduce operator's experiences and improve the design efficiency and quality of surgical guide. Few literatures can be found on this topic and the paper proposed a novel and simple method to solve this problem. In this paper, a local coordinate system for each objective tooth is geometrically constructed in CAD system. This coordinate system well represents dental anatomical features and the center axis of the objective tooth (coincide with the corresponding guide hole axis) can be quickly evaluated in this coordinate system, finishing the location of the guide hole. The proposed method has been verified by comparing two types of benchmarks: manual operation by one skilled doctor with over 15-year experiences (used in most hospitals) and automatic way using one popular commercial package Simplant (used in few hospitals).Both the benchmarks and the proposed method are analyzed in their stress distribution when chewing and biting. The stress distribution is visually shown and plotted as a graph. The results show that the proposed method has much better stress distribution than the manual operation and slightly better than Simplant, which will significantly reduce the risk of cervical margin collapse and extend the wear life of the restoration.

Advances and limitations of visual conditioning protocols in harnessed bees.

PubMed

Avarguès-Weber, Aurore; Mota, Theo

2016-10-01

Bees are excellent invertebrate models for studying visual learning and memory mechanisms, because of their sophisticated visual system and impressive cognitive capacities associated with a relatively simple brain. Visual learning in free-flying bees has been traditionally studied using an operant conditioning paradigm. This well-established protocol, however, can hardly be combined with invasive procedures for studying the neurobiological basis of visual learning. Different efforts have been made to develop protocols in which harnessed honey bees could associate visual cues with reinforcement, though learning performances remain poorer than those obtained with free-flying animals. Especially in the last decade, the intention of improving visual learning performances of harnessed bees led many authors to adopt distinct visual conditioning protocols, altering parameters like harnessing method, nature and duration of visual stimulation, number of trials, inter-trial intervals, among others. As a result, the literature provides data hardly comparable and sometimes contradictory. In the present review, we provide an extensive analysis of the literature available on visual conditioning of harnessed bees, with special emphasis on the comparison of diverse conditioning parameters adopted by different authors. Together with this comparative overview, we discuss how these diverse conditioning parameters could modulate visual learning performances of harnessed bees. Copyright © 2016 Elsevier Ltd. All rights reserved.

Rendering visual events as sounds: Spatial attention capture by auditory augmented reality.

PubMed

Stone, Scott A; Tata, Matthew S

2017-01-01

Many salient visual events tend to coincide with auditory events, such as seeing and hearing a car pass by. Information from the visual and auditory senses can be used to create a stable percept of the stimulus. Having access to related coincident visual and auditory information can help for spatial tasks such as localization. However not all visual information has analogous auditory percepts, such as viewing a computer monitor. Here, we describe a system capable of detecting and augmenting visual salient events into localizable auditory events. The system uses a neuromorphic camera (DAVIS 240B) to detect logarithmic changes of brightness intensity in the scene, which can be interpreted as salient visual events. Participants were blindfolded and asked to use the device to detect new objects in the scene, as well as determine direction of motion for a moving visual object. Results suggest the system is robust enough to allow for the simple detection of new salient stimuli, as well accurately encoding direction of visual motion. Future successes are probable as neuromorphic devices are likely to become faster and smaller in the future, making this system much more feasible.

Developmental outcome, including setback, in young children with severe visual impairment.

PubMed

Dale, Naomi; Sonksen, Patricia

2002-09-01

This study retrospectively investigated the developmental perspective of 69 children (40 males, 29 females) with 'potentially simple' congenital disorders of the peripheral visual system: development was examined in the context of degree of visual impairment. Developmental and visual assessments were carried out at 10 to 16 months (Time 1) and 27 to 54 months of age (Time 2). Participants were grouped according to (1) visual status: profound visual impairment (PVI), severe visual impairment (SVI); (2) developmental status on the Reynell-Zinkin scales. A majority of the sample showed normal development on all subscales (62% Time 1, 57% Time 2). Those with PVI were more developmentally vulnerable than SVI with a greater incidence of (1) uneven developmental profile at Time 1 (48% PVI, 16% SVI); (2) global learning difficulties at Time 2 (37% PVI, 0% SVI); (3) delay on individual subscales at Time 2 (p<0.02 PVI versus SVI); (4) deceleration (verbal comprehension 74% PVI, 24% SVI, sensorimotor understanding 70% PVI, 27% SVI); and (5) severe developmental setback (33% PVI, 7% SVI). Risk factors of visual level, age, and sex for poor developmental outcome in infants with visual impairment were established.

Rendering visual events as sounds: Spatial attention capture by auditory augmented reality

PubMed Central

Tata, Matthew S.

2017-01-01

Many salient visual events tend to coincide with auditory events, such as seeing and hearing a car pass by. Information from the visual and auditory senses can be used to create a stable percept of the stimulus. Having access to related coincident visual and auditory information can help for spatial tasks such as localization. However not all visual information has analogous auditory percepts, such as viewing a computer monitor. Here, we describe a system capable of detecting and augmenting visual salient events into localizable auditory events. The system uses a neuromorphic camera (DAVIS 240B) to detect logarithmic changes of brightness intensity in the scene, which can be interpreted as salient visual events. Participants were blindfolded and asked to use the device to detect new objects in the scene, as well as determine direction of motion for a moving visual object. Results suggest the system is robust enough to allow for the simple detection of new salient stimuli, as well accurately encoding direction of visual motion. Future successes are probable as neuromorphic devices are likely to become faster and smaller in the future, making this system much more feasible. PMID:28792518

Mathematical neuroscience: from neurons to circuits to systems.

PubMed

Gutkin, Boris; Pinto, David; Ermentrout, Bard

2003-01-01

Applications of mathematics and computational techniques to our understanding of neuronal systems are provided. Reduction of membrane models to simplified canonical models demonstrates how neuronal spike-time statistics follow from simple properties of neurons. Averaging over space allows one to derive a simple model for the whisker barrel circuit and use this to explain and suggest several experiments. Spatio-temporal pattern formation methods are applied to explain the patterns seen in the early stages of drug-induced visual hallucinations.

Unveiling Angular Momentum

NASA Astrophysics Data System (ADS)

Robinson, Stephen

2015-03-01

Angular momentum is a notoriously difficult concept to grasp. Visualization often requires three-dimensional pictures of vectors pointing in seemingly arbitrary directions. A simple student-run laboratory experiment coupled with intuitive explanations by an instructor can clear up some of the inherent ambiguity of rotational motion. Specifically, the precessional period of a suspended spinning bicycle wheel can be related to the spinning frequency through a simple algebraic expression. An explanation of this precession apart from the concept of angular momentum will be given.

Protein-Protein Interaction Network and Gene Ontology

NASA Astrophysics Data System (ADS)

Choi, Yunkyu; Kim, Seok; Yi, Gwan-Su; Park, Jinah

Evolution of computer technologies makes it possible to access a large amount and various kinds of biological data via internet such as DNA sequences, proteomics data and information discovered about them. It is expected that the combination of various data could help researchers find further knowledge about them. Roles of a visualization system are to invoke human abilities to integrate information and to recognize certain patterns in the data. Thus, when the various kinds of data are examined and analyzed manually, an effective visualization system is an essential part. One instance of these integrated visualizations can be combination of protein-protein interaction (PPI) data and Gene Ontology (GO) which could help enhance the analysis of PPI network. We introduce a simple but comprehensive visualization system that integrates GO and PPI data where GO and PPI graphs are visualized side-by-side and supports quick reference functions between them. Furthermore, the proposed system provides several interactive visualization methods for efficiently analyzing the PPI network and GO directedacyclic- graph such as context-based browsing and common ancestors finding.

Emergence of Orientation Selectivity in the Mammalian Visual Pathway

PubMed Central

Scholl, Benjamin; Tan, Andrew Y. Y.; Corey, Joseph

2013-01-01

Orientation selectivity is a property of mammalian primary visual cortex (V1) neurons, yet its emergence along the visual pathway varies across species. In carnivores and primates, elongated receptive fields first appear in V1, whereas in lagomorphs such receptive fields emerge earlier, in the retina. Here we examine the mouse visual pathway and reveal the existence of orientation selectivity in lateral geniculate nucleus (LGN) relay cells. Cortical inactivation does not reduce this orientation selectivity, indicating that cortical feedback is not its source. Orientation selectivity is similar for LGN relay cells spiking and subthreshold input to V1 neurons, suggesting that cortical orientation selectivity is inherited from the LGN in mouse. In contrast, orientation selectivity of cat LGN relay cells is small relative to subthreshold inputs onto V1 simple cells. Together, these differences show that although orientation selectivity exists in visual neurons of both rodents and carnivores, its emergence along the visual pathway, and thus its underlying neuronal circuitry, is fundamentally different. PMID:23804085

Synaptic and Network Mechanisms of Sparse and Reliable Visual Cortical Activity during Nonclassical Receptive Field Stimulation

PubMed Central

Haider, Bilal; Krause, Matthew R.; Duque, Alvaro; Yu, Yuguo; Touryan, Jonathan; Mazer, James A.; McCormick, David A.

2011-01-01

SUMMARY During natural vision, the entire visual field is stimulated by images rich in spatiotemporal structure. Although many visual system studies restrict stimuli to the classical receptive field (CRF), it is known that costimulation of the CRF and the surrounding nonclassical receptive field (nCRF) increases neuronal response sparseness. The cellular and network mechanisms underlying increased response sparseness remain largely unexplored. Here we show that combined CRF + nCRF stimulation increases the sparseness, reliability, and precision of spiking and membrane potential responses in classical regular spiking (RSC) pyramidal neurons of cat primary visual cortex. Conversely, fast-spiking interneurons exhibit increased activity and decreased selectivity during CRF + nCRF stimulation. The increased sparseness and reliability of RSC neuron spiking is associated with increased inhibitory barrages and narrower visually evoked synaptic potentials. Our experimental observations were replicated with a simple computational model, suggesting that network interactions among neuronal subtypes ultimately sharpen recurrent excitation, producing specific and reliable visual responses. PMID:20152117

Neuronal connectome of a sensory-motor circuit for visual navigation

PubMed Central

Randel, Nadine; Asadulina, Albina; Bezares-Calderón, Luis A; Verasztó, Csaba; Williams, Elizabeth A; Conzelmann, Markus; Shahidi, Réza; Jékely, Gáspár

2014-01-01

Animals use spatial differences in environmental light levels for visual navigation; however, how light inputs are translated into coordinated motor outputs remains poorly understood. Here we reconstruct the neuronal connectome of a four-eye visual circuit in the larva of the annelid Platynereis using serial-section transmission electron microscopy. In this 71-neuron circuit, photoreceptors connect via three layers of interneurons to motorneurons, which innervate trunk muscles. By combining eye ablations with behavioral experiments, we show that the circuit compares light on either side of the body and stimulates body bending upon left-right light imbalance during visual phototaxis. We also identified an interneuron motif that enhances sensitivity to different light intensity contrasts. The Platynereis eye circuit has the hallmarks of a visual system, including spatial light detection and contrast modulation, illustrating how image-forming eyes may have evolved via intermediate stages contrasting only a light and a dark field during a simple visual task. DOI: http://dx.doi.org/10.7554/eLife.02730.001 PMID:24867217

The simplest chronoscope II: reaction time measured by meterstick versus machine.

PubMed

Montare, Alberto

2010-12-01

Visual simple reaction time (SRT) scores measured in 31 college students of both sexes by use of the simplest chronoscope methodology (meterstick SRT) were compared to scores obtained by use of an electromechanical multi-choice reaction timer (machine SRT). Four hypotheses were tested. Results indicated that the previous mean value of meterstick SRT was replicated; meterstick SRT was significantly faster than long-standing population estimates of mean SRT; and machine SRT was significantly slower than the same long-standing mean SRT estimates for the population. Also, the mean meterstick SRT of 181 msec. was significantly faster than the mean machine SRT of 294 msec. It was theorized that differential visual information processing occurred such that the dorsal visual stream subserved meterstick SRT; whereas the ventral visual stream subserved machine SRT.

Influence of outdoor advertisement colors on psychological evaluation of townscape in Kyoto

NASA Astrophysics Data System (ADS)

Onishi, Ayumi; Ishida, Taiichiro; Katsuya, Yoshiko

2002-06-01

Outdoor advertisements must be one of the major factors that affect our psychological impression for townscapes. They often conflict with propr color environments in cities particularly in historic cities like Kyoto. In this study we investigated how outdoor advertisements influenced our visual evaluation of townscapes in Kyoto. In recent years, a new regulation for outdoor advertisements came into operation in Kyoto and some of the advertisements have been replaced or removed gradually. We examined psychological evaluation for the townscapes before and after their changes. In the experiment, subjects evaluated 'visual harmony,' 'visual busyness,' 'visual comfort' and 'suitability to Kyoto' of townscapes projected on a screen. The results indicated that the evaluation of 'visual busyness' significantly decreased with the amount of the advertisements. The relations between the advertisements and the psychological evaluation of the townscape are discussed.

Heads Up, Shoulders Straight, Stick and Twirl Together

ERIC Educational Resources Information Center

Warrick, James

1977-01-01

With so many roles to juggle and so many complex music problems to resolve, some marching band directors overlook simple rules of thumb to increase their bands' visual and musical impact. Here are some guidelines. (Author/RK)

Visual short-term memory capacity for simple and complex objects.

PubMed

Luria, Roy; Sessa, Paola; Gotler, Alex; Jolicoeur, Pierre; Dell'Acqua, Roberto

2010-03-01

Does the capacity of visual short-term memory (VSTM) depend on the complexity of the objects represented in memory? Although some previous findings indicated lower capacity for more complex stimuli, other results suggest that complexity effects arise during retrieval (due to errors in the comparison process with what is in memory) that is not related to storage limitations of VSTM, per se. We used ERPs to track neuronal activity specifically related to retention in VSTM by measuring the sustained posterior contralateral negativity during a change detection task (which required detecting if an item was changed between a memory and a test array). The sustained posterior contralateral negativity, during the retention interval, was larger for complex objects than for simple objects, suggesting that neurons mediating VSTM needed to work harder to maintain more complex objects. This, in turn, is consistent with the view that VSTM capacity depends on complexity.

Lack of power enhances visual perceptual discrimination.

PubMed

Weick, Mario; Guinote, Ana; Wilkinson, David

2011-09-01

Powerless individuals face much challenge and uncertainty. As a consequence, they are highly vigilant and closely scrutinize their social environments. The aim of the present research was to determine whether these qualities enhance performance in more basic cognitive tasks involving simple visual feature discrimination. To test this hypothesis, participants performed a series of perceptual matching and search tasks involving colour, texture, and size discrimination. As predicted, those primed with powerlessness generated shorter reaction times and made fewer eye movements than either powerful or control participants. The results indicate that the heightened vigilance shown by powerless individuals is associated with an advantage in performing simple types of psychophysical discrimination. These findings highlight, for the first time, an underlying competency in perceptual cognition that sets powerless individuals above their powerful counterparts, an advantage that may reflect functional adaptation to the environmental challenge and uncertainty that they face. © 2011 Canadian Psychological Association

Eighteen-month-olds' memory for short movies of simple stories.

PubMed

Kingo, Osman S; Krøjgaard, Peter

2015-04-01

This study investigated twenty four 18-month-olds' memory for dynamic visual stimuli. During the first visit participants saw one of two brief movies (30 seconds) with a simple storyline displayed in four iterations. After 2 weeks, memory was tested in the visual paired comparison paradigm in which the familiar and the novel movie were contrasted simultaneously and displayed in two iterations for a total of 60 seconds. Eye-tracking revealed that participants fixated the familiar movie significantly more than the novel movie, thus indicating memory for the familiar movie. Furthermore, time-dependent analysis of the data revealed that individual differences in the looking-patterns for the first and second iteration of the movies were related to individual differences in productive vocabulary. We suggest that infants' vocabulary may be indicative of their ability to understand and remember the storyline of the movies, thereby affecting their subsequent memory. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Visual field defects may not affect safe driving.

PubMed

Dow, Jamie

2011-10-01

In Quebec a driver whose acquired visual field defect renders them ineligible for a driver's permit renewal may request an exemption from the visual field standard by demonstrating safe driving despite the defect. For safety reasons it was decided to attempt to identify predictors of failure on the road test in order to avoid placing driving evaluators in potentially dangerous situations when evaluating drivers with visual field defects. During a 4-month period in 2009 all requests for exemptions from the visual field standard were collected and analyzed. All available medical and visual field data were collated for 103 individuals, of whom 91 successfully completed the evaluation process and obtained a waiver. The collated data included age, sex, type of visual field defect, visual field characteristics, and concomitant medical problems. No single factor, or combination of factors, could predict failure of the road test. All 5 failures of the road test had cognitive problems but 6 of the successful drivers also had known cognitive problems. Thus, cognitive problems influence the risk of failure but do not predict certain failure. Most of the applicants for an exemption were able to complete the evaluation process successfully, thereby demonstrating safe driving despite their handicap. Consequently, jurisdictions that have visual field standards for their driving permit should implement procedures to evaluate drivers with visual field defects that render them unable to meet the standard but who wish to continue driving.

The Value of Data and Metadata Standardization for Interoperability in Giovanni Or: Why Your Product's Metadata Causes Us Headaches!

NASA Technical Reports Server (NTRS)

Smit, Christine; Hegde, Mahabaleshwara; Strub, Richard; Bryant, Keith; Li, Angela; Petrenko, Maksym

2017-01-01

Giovanni is a data exploration and visualization tool at the NASA Goddard Earth Sciences Data Information Services Center (GES DISC). It has been around in one form or another for more than 15 years. Giovanni calculates simple statistics and produces 22 different visualizations for more than 1600 geophysical parameters from more than 90 satellite and model products. Giovanni relies on external data format standards to ensure interoperability, including the NetCDF CF Metadata Conventions. Unfortunately, these standards were insufficient to make Giovanni's internal data representation truly simple to use. Finding and working with dimensions can be convoluted with the CF Conventions. Furthermore, the CF Conventions are silent on machine-friendly descriptive metadata such as the parameter's source product and product version. In order to simplify analyzing disparate earth science data parameters in a unified way, we developed Giovanni's internal standard. First, the format standardizes parameter dimensions and variables so they can be easily found. Second, the format adds all the machine-friendly metadata Giovanni needs to present our parameters to users in a consistent and clear manner. At a glance, users can grasp all the pertinent information about parameters both during parameter selection and after visualization.