WorldWideScience

Sample records for visual map mechanisms

  1. Visualizing Dynamic Data with Maps.

    Science.gov (United States)

    Mashima, Daisuke; Kobourov, Stephen G; Hu, Yifan

    2012-09-01

    Maps offer a familiar way to present geographic data (continents, countries), and additional information (topography, geology), can be displayed with the help of contours and heat-map overlays. In this paper, we consider visualizing large-scale dynamic relational data by taking advantage of the geographic map metaphor. We describe a map-based visualization system which uses animation to convey dynamics in large data sets, and which aims to preserve the viewer's mental map while also offering readable views at all times. Our system is fully functional and has been used to visualize user traffic on the Internet radio station last.fm, as well as TV-viewing patterns from an IPTV service. All map images in this paper are available in high-resolution at [1] as are several movies illustrating the dynamic visualization.

  2. Advanced Visual Quantum Mechanics

    CERN Document Server

    Thaller, Bernd

    2005-01-01

    Advanced Visual Quantum Mechanics is a systematic effort to investigate and to teach quantum mechanics with the aid of computer-generated animations. It is a self-contained textbook that combines selected topics from atomic physics (spherical symmetry, the hydrogen atom, and particles with spin) with an introduction to quantum information theory (qubits, EPR paradox, teleportation, quantum computers). It explores relativistic quantum mechanics and the strange behavior of Dirac equation solutions. A series of appendices covers important topics from perturbation and scattering theory. The book places an emphasis on ideas and concepts, with a fair to moderate amount of mathematical rigor. Though this book stands alone, it can also be paired with Thaller Visual Quantum Mechanics to form a comprehensive course in quantum mechanics. The software for the first book earned the European Academic Software Award 2000 for outstanding innovation in its field.

  3. Visual Abstraction and Stylisation of Maps

    NARCIS (Netherlands)

    Isenberg, Tobias

    We explore visual map abstraction for the generation of stylized renderings of 2D map data. We employ techniques that are centred around the concept of shape simplification and graph layout and that allow iterative abstraction of 2D maps. We use data from publicly available sources and show how we

  4. Building maps from maps in primary visual cortex.

    Science.gov (United States)

    Nauhaus, Ian; Nielsen, Kristina J

    2014-02-01

    Neurons in the visual system respond to more complex and holistic features at each new stage of processing. Often, these features are organized into continuous maps. Could there be a fundamental link between continuous maps and functional hierarchies? Here, we review recent studies regarding V1 maps providing some of the most noteworthy advances in our understanding of how and why maps exist. In particular, we focus on the common theme that some maps are inherited from the input of parallel pathways, which are then intimately linked to the emergence of new functional properties and their corresponding maps. These results on V1 maps may prove to be a unifying framework for hierarchical representations in the visual cortex. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Musician Map: visualizing music collaborations over time

    Science.gov (United States)

    Yim, Ji-Dong; Shaw, Chris D.; Bartram, Lyn

    2009-01-01

    In this paper we introduce Musician Map, a web-based interactive tool for visualizing relationships among popular musicians who have released recordings since 1950. Musician Map accepts search terms from the user, and in turn uses these terms to retrieve data from MusicBrainz.org and AudioScrobbler.net, and visualizes the results. Musician Map visualizes relationships of various kinds between music groups and individual musicians, such as band membership, musical collaborations, and linkage to other artists that are generally regarded as being similar in musical style. These relationships are plotted between artists using a new timeline-based visualization where a node in a traditional node-link diagram has been transformed into a Timeline-Node, which allows the visualization of an evolving entity over time, such as the membership in a band. This allows the user to pursue social trend queries such as "Do Hip-Hop artists collaborate differently than Rock artists".

  6. Adaptive strategies of the visualization of electronic map

    Science.gov (United States)

    Wang, Hong; Ai, Tinghua

    2006-10-01

    The visualization of electronic map should be dynamic not only in the way of representation but also in the content creation in real time. In on-demand mapping, the user's favorites to map content are the key factor. It means that the design of electronic map has to consider providing several candidate visualizations according to the user's context. To settle on-demand question, the adaptive visualization has been an active topic in the field of map design in recent years. Based on practical experiments, this paper tries to present some adaptive strategies on the visualization of electronic map. Firstly, a conceptual framework of adaptive visualization is proposed, what includes the parts of the context interface, the map behaviors triggering factors, the adaptive mechanism, hierarchy control, output of result map, and the evaluation methods. We consider three main factors associated with the adaptive visualization: (1). the user's interactive map behaviors, (2). the context of the surroundings where the electronic map system stays, (3). the user category under their knowledge and experiences. The map behaviors include the ZOOM OUT, ZOOM IN, PAN, QUERY, ROTATION, and etc, which will result in changes for the contents and structures of map. These changes relate to the aspects about Map Extent, Scale, Location, Quantity, Quality, Direction, Density, and etc. The surroundings of map reading include the screen size, color display or B/W display, brightness, weather, special light scenery, speed of data loading, display sets, sound, time, event, culture, language, and etc. The map design has to provide different strategies to satisfy the periphery environment changes. According to some egocentric conditions, i.e., Location, Moving Orientation, Speed of Motion, and Self Properties, this paper gives some practical illustrations and descriptive maps. The classification of map users considers their knowledge, experience and specialty. We divide users into different levels

  7. Network visualization: mapping Shakespeare's tragedies

    OpenAIRE

    Grandjean, Martin

    2015-01-01

    Blogpost, http://www.martingrandjean.ch/network-visualization-shakespeare/; Are Shakespeare's tragedies all structured in the same way? Are the characters rather isolated, grouped, all connected? Narration, even fictional, contains a network of interacting characters. Constituting a well defined corpus, the eleven Shakespearean tragedies can easily be compared: We propose here a network visualization in which each character is represented by a node connected with the characters that appear in...

  8. Making maps a visual guide to map design for GIS

    CERN Document Server

    Krygier, John

    2016-01-01

    Lauded for its accessibility and beautiful design, this text has given thousands of students and professionals the tools to create effective, compelling maps. Using a wealth of illustrations--with 74 in full color--to elucidate each concisely presented point, the revised and updated third edition continues to emphasize how design choices relate to the reasons for making a map and its intended purpose. All components of map making are covered: titles, labels, legends, visual hierarchy, font selection, how to turn phenomena into visual data, data organization, symbolization, and more. Innovative

  9. CMView: interactive contact map visualization and analysis.

    Science.gov (United States)

    Vehlow, Corinna; Stehr, Henning; Winkelmann, Matthias; Duarte, José M; Petzold, Lars; Dinse, Juliane; Lappe, Michael

    2011-06-01

    Contact maps are a valuable visualization tool in structural biology. They are a convenient way to display proteins in two dimensions and to quickly identify structural features such as domain architecture, secondary structure and contact clusters. We developed a tool called CMView which integrates rich contact map analysis with 3D visualization using PyMol. Our tool provides functions for contact map calculation from structure, basic editing, visualization in contact map and 3D space and structural comparison with different built-in alignment methods. A unique feature is the interactive refinement of structural alignments based on user selected substructures. CMView is freely available for Linux, Windows and MacOS. The software and a comprehensive manual can be downloaded from http://www.bioinformatics.org/cmview/. The source code is licensed under the GNU General Public License.

  10. Visual Map Shifts based on Whisker-Guided Cues in the Young Mouse Visual Cortex

    Directory of Open Access Journals (Sweden)

    Kohei Yoshitake

    2013-12-01

    Full Text Available Mice navigate nearby space using their vision and whiskers, and young mice learn to integrate these heterogeneous inputs in perceptual space. We found that cortical responses were depressed in the primary visual cortex of young mice after wearing a monocular prism. This depression was uniformly observed in the primary visual cortex and was eliminated by whisker trimming or lesions in the posterior parietal cortex. Compensatory visual map shifts of responses elicited via the eye that had worn the prism were also observed. As a result, cortical responses elicited via each eye were clearly separated when a visual stimulus was placed in front of the mice. A comparison of response areas before and after prism wearing indicated that the map shifts were produced by depression with spatial eccentricity. Visual map shifts based on whisker-guided cues may serve as a model for investigating the cellular and molecular mechanisms underlying higher sensory integration in the mammalian brain.

  11. Visualizing archives: Spanish archives map

    OpenAIRE

    María-Jesús Colmenero-Ruiz

    2016-01-01

    The 2014/2015 academic year was the first to be taught the Master in Archives, Records Management and Digital Continuity at the University Carlos III Madrid, based on a blended learning model of attendance. This article describes the implementation of a visualization project based on geolocation of Spanish archives and its justification. The project arose from an optional practice proposed to the students of the subject “Re-use of data and documents” of this master course. This subject is opt...

  12. Patent Overlay Mapping: Visualizing Technological Distance

    CERN Document Server

    Kay, Luciano; Youtie, Jan; Porter, Alan L; Rafols, Ismael

    2012-01-01

    The purpose of this paper is to present a new global patent map that represents all technological categories, and a method to locate patent data of individual organizations and technological fields on the global map. This second patent overlay map technique is shown to be of potential interest to support competitive intelligence and policy decision-making. The global patent map is based on similarities in citing-to-cited relationships between categories of the International Patent Classification (IPC) of European Patent Office (EPO) patents from 2000 to 2006. This patent dataset, extracted from PatStat database, represents more than 760,000 patent records in more than 400 IPC categories. To illustrate the kind of analytical support offered by this approach, the paper shows the overlay of nanotechnology-related patenting activities of two companies and two different nanotechnology subfields on to the global patent map. The exercise shows the potential of patent overlay maps to visualize technological areas and...

  13. Visualizing archives: Spanish archives map

    Directory of Open Access Journals (Sweden)

    María-Jesús Colmenero-Ruiz

    2016-05-01

    Full Text Available The 2014/2015 academic year was the first to be taught the Master in Archives, Records Management and Digital Continuity at the University Carlos III Madrid, based on a blended learning model of attendance. This article describes the implementation of a visualization project based on geolocation of Spanish archives and its justification. The project arose from an optional practice proposed to the students of the subject “Re-use of data and documents” of this master course. This subject is opt...

  14. Visual SLAM Using Variance Grid Maps

    Science.gov (United States)

    Howard, Andrew B.; Marks, Tim K.

    2011-01-01

    An algorithm denoted Gamma-SLAM performs further processing, in real time, of preprocessed digitized images acquired by a stereoscopic pair of electronic cameras aboard an off-road robotic ground vehicle to build accurate maps of the terrain and determine the location of the vehicle with respect to the maps. Part of the name of the algorithm reflects the fact that the process of building the maps and determining the location with respect to them is denoted simultaneous localization and mapping (SLAM). Most prior real-time SLAM algorithms have been limited in applicability to (1) systems equipped with scanning laser range finders as the primary sensors in (2) indoor environments (or relatively simply structured outdoor environments). The few prior vision-based SLAM algorithms have been feature-based and not suitable for real-time applications and, hence, not suitable for autonomous navigation on irregularly structured terrain. The Gamma-SLAM algorithm incorporates two key innovations: Visual odometry (in contradistinction to wheel odometry) is used to estimate the motion of the vehicle. An elevation variance map (in contradistinction to an occupancy or an elevation map) is used to represent the terrain. The Gamma-SLAM algorithm makes use of a Rao-Blackwellized particle filter (RBPF) from Bayesian estimation theory for maintaining a distribution over poses and maps. The core idea of the RBPF approach is that the SLAM problem can be factored into two parts: (1) finding the distribution over robot trajectories, and (2) finding the map conditioned on any given trajectory. The factorization involves the use of a particle filter in which each particle encodes both a possible trajectory and a map conditioned on that trajectory. The base estimate of the trajectory is derived from visual odometry, and the map conditioned on that trajectory is a Cartesian grid of elevation variances. In comparison with traditional occupancy or elevation grid maps, the grid elevation variance

  15. Visualization of neural networks using saliency maps

    DEFF Research Database (Denmark)

    Mørch, Niels J.S.; Kjems, Ulrik; Hansen, Lars Kai

    1995-01-01

    The saliency map is proposed as a new method for understanding and visualizing the nonlinearities embedded in feedforward neural networks, with emphasis on the ill-posed case, where the dimensionality of the input-field by far exceeds the number of examples. Several levels of approximations...

  16. A Visual Language for Data Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J

    2001-08-10

    I discuss a visual programming language and environment for doing data mapping between textual data files. Our experience using the environment is documented, as well as many of the constructs we used in the environment. I relate problems and solutions, and pose some questions to the readers of this document and the workshop.

  17. Visualizing Meta-Features in Proteomic Maps

    Directory of Open Access Journals (Sweden)

    Lepouras George

    2011-07-01

    Full Text Available Abstract Background The steps of a high-throughput proteomics experiment include the separation, differential expression and mass spectrometry-based identification of proteins. However, the last and more challenging step is inferring the biological role of the identified proteins through their association with interaction networks, biological pathways, analysis of the effect of post-translational modifications, and other protein-related information. Results In this paper, we present an integrative visualization methodology that allows combining experimentally produced proteomic features with protein meta-features, typically coming from meta-analysis tools and databases, in synthetic Proteomic Feature Maps. Using three proteomics analysis scenarios, we show that the proposed visualization approach is effective in filtering, navigating and interacting with the proteomics data in order to address visually challenging biological questions. The novelty of our approach lies in the ease of integration of any user-defined proteomic features in easy-to-comprehend visual representations that resemble the familiar 2D-gel images, and can be adapted to the user's needs. The main capabilities of the developed VIP software, which implements the presented visualization methodology, are also highlighted and discussed. Conclusions By using this visualization and the associated VIP software, researchers can explore a complex heterogeneous proteomics dataset from different perspectives in order to address visually important biological queries and formulate new hypotheses for further investigation. VIP is freely available at http://pelopas.uop.gr/~egian/VIP/index.html.

  18. Declarative and Scalable Selection for Map Visualizations

    DEFF Research Database (Denmark)

    Kefaloukos, Pimin Konstantin Balic

    supports the PostgreSQL dialect of SQL. The prototype implementation is a compiler that translates CVL into SQL and stored procedures. (c) TileHeat is a framework and basic algorithm for partial materialization of hot tile sets for scalable map distribution. The framework predicts future map workloads......, there are indications that the method is scalable for databases that contain millions of records, especially if the target language of the compiler is substituted by a cluster-ready variant of SQL. While several realistic use cases for maps have been implemented in CVL, additional non-geographic data visualization uses...... goal. The results for Tileheat show that the prediction method offers a substantial improvement over the current method used by the Danish Geodata Agency. Thus, a large amount of computations can potentially be saved by this public institution, who is responsible for the distribution of government...

  19. Visual Tools for Quantum Mechanics Education

    OpenAIRE

    Bernd Thaller

    2006-01-01

    We present the project Visual Quantum Mechanics, which uses computer-generated visualizations and animations to redefine content and quality of quantum-mechanical education at all levels. Main target group have been students of theoretical physics at universities, but more recently, we have developed learning objects for use at high schools. We describe the reasons for a visual approach to quantum mechanics and some specific methods for the visualization of quantum-mechanical objects.

  20. Visual Tools for Quantum Mechanics Education

    Directory of Open Access Journals (Sweden)

    Bernd Thaller

    2006-07-01

    Full Text Available We present the project Visual Quantum Mechanics, which uses computer-generated visualizations and animations to redefine content and quality of quantum-mechanical education at all levels. Main target group have been students of theoretical physics at universities, but more recently, we have developed learning objects for use at high schools. We describe the reasons for a visual approach to quantum mechanics and some specific methods for the visualization of quantum-mechanical objects.

  1. Visually-driven maps in area 3b.

    Science.gov (United States)

    Kuehn, Esther; Haggard, Patrick; Villringer, Arno; Pleger, Burkhard; Sereno, Martin I

    2018-01-04

    Sensory perception relies on the precise neuronal encoding of modality-specific environmental features in primary sensory cortices. Some studies have reported the penetration of signals from other modalities even into early sensory areas. So far, no comprehensive account of maps induced by "foreign sources" exists. We addressed this question using surface-based topographic mapping techniques applied to ultra-high resolution fMRI neuroimaging data, measured in female participants. We show that fine-grained finger maps in human primary somatosensory cortex, area 3b, are somatotopically activated not only during tactile mechanical stimulation, but also when viewing the same fingers being touched. Visually-induced maps were weak in amplitude, but overlapped with the stronger tactile maps tangential to the cortical sheet when finger touches were observed in both first- and third-person perspectives. However, visually-induced maps did not overlap tactile maps when the observed fingers were only approached by an object but not actually touched. Our data provide evidence that "foreign source maps" in early sensory cortices are present in the healthy human brain, that their arrangement is precise, and that their induction is feature-selective. The computations required to generate such specific responses suggest that counterflow (feedback) processing may be much more spatially specific than has been often assumed.SIGNIFICANCE STATEMENTUsing ultra-high field fMRI, we provide empirical evidence that viewing touches activates topographically aligned single finger maps in human primary somatosensory cortical area 3b. This shows that "foreign source maps" in early sensory cortices are topographic, precise, and feature-selective in healthy human participants with intact sensory pathways. Copyright © 2018 the authors.

  2. Probing the Feature Map for Faces in Visual Search

    Directory of Open Access Journals (Sweden)

    Hua Yang

    2011-05-01

    Full Text Available Controversy surrounds the mechanisms underlying the pop-out effect for faces in visual search. Is there a feature map for faces? If so, does it rely on the categorical distinction between faces and nonfaces, or on image-level face semblance? To probe the feature map, we compared search efficiency for faces, and nonface stimuli with high, low, and no face semblance. First, subjects performed a visual search task with objects as distractors. Only faces popped-out. Moreover, search efficiency for nonfaces correlated with image-level face semblance of the target. In a second experiment, faces were used as distractors but nonfaces did not pop-out. Interestingly, search efficiency for nonfaces was not modulated by face semblance, although searching for a face among faces was particularly difficult, reflecting a categorical boundary between nonfaces and faces. Finally, inversion and contrast negation significantly interacted with the effect of face semblance, ruling out the possibility that search efficiency solely depends on low-level features. Our study supports a parallel search for faces that is perhaps preattentive. Like other features (color, orientation etc., there appears to be a continuous face feature map for visual search. Our results also suggest that this map may include both image-level face semblance and face categoricity.

  3. Intrathalamic mechanisms of visual attention.

    Science.gov (United States)

    Mayo, J Patrick

    2009-03-01

    The classical model of visual processing emphasizes the lateral geniculate nucleus (LGN) as the major intermediary between the retina and visual cortex. Yet, anatomical findings inspired Francis Crick to suggest an alternative model in which the thalamic reticular nucleus, which envelops the LGN, acts as the "guardian" of visual cortex by modulating LGN activity. Recent work by McAlonan and colleagues supports Crick's hypothesis, thereby enhancing our understanding of the early stages of visual processing.

  4. Toward Lifelong Visual Localization and Mapping

    Science.gov (United States)

    2013-06-01

    estimation there are nodes for communicating to the vehicle and the DIDSON sonar. An architecture diagram is shown in Figure 3-9. The mapping server...for pose graph optimization, which also includes an incremental implementation of the Powell’s Dog Leg algorithm [89] allowing the use of robust...scan matching algorithm using a mechan- ical scanned imaging sonar. In OCEANS 2009- EUROPE , 2009. OCEANS ’09., pages 1–6, May 2009. [70] J. McDonald, M

  5. Visualization of nonlinear kernel models in neuroimaging by sensitivity maps

    DEFF Research Database (Denmark)

    Rasmussen, Peter Mondrup; Hansen, Lars Kai; Madsen, Kristoffer Hougaard

    on visualization of such nonlinear kernel models. Specifically, we investigate the sensitivity map as a technique for generation of global summary maps of kernel classification methods. We illustrate the performance of the sensitivity map on functional magnetic resonance (fMRI) data based on visual stimuli. We...... show that the performance of linear models is reduced for certain scan labelings/categorizations in this data set, while the nonlinear models provide more flexibility. We show that the sensitivity map can be used to visualize nonlinear versions of kernel logistic regression, the kernel Fisher...

  6. Visual explorations of dynamics: The standard map

    Indian Academy of Sciences (India)

    The Macintosh application StdMap allows easy exploration of many of the phenomena of area-preserving mappings. This tutorial explains some of these phenomena and presents a number of simple experiments centered on the use of this program.

  7. Mapping as a visual health communication tool: promises and dilemmas.

    Science.gov (United States)

    Parrott, Roxanne; Hopfer, Suellen; Ghetian, Christie; Lengerich, Eugene

    2007-01-01

    In the era of evidence-based public health promotion and planning, the use of maps as a form of evidence to communicate about the multiple determinants of cancer is on the rise. Geographic information systems and mapping technologies make future proliferation of this strategy likely. Yet disease maps as a communication form remain largely unexamined. This content analysis considers the presence of multivariate information, credibility cues, and the communication function of publicly accessible maps for cancer control activities. Thirty-six state comprehensive cancer control plans were publicly available in July 2005 and were reviewed for the presence of maps. Fourteen of the 36 state cancer plans (39%) contained map images (N = 59 static maps). A continuum of map inter activity was observed, with 10 states having interactive mapping tools available to query and map cancer information. Four states had both cancer plans with map images and interactive mapping tools available to the public on their Web sites. Of the 14 state cancer plans that depicted map images, two displayed multivariate data in a single map. Nine of the 10 states with interactive mapping capability offered the option to display multivariate health risk messages. The most frequent content category mapped was cancer incidence and mortality, with stage at diagnosis infrequently available. The most frequent communication function served by the maps reviewed was redundancy, as maps repeated information contained in textual forms. The social and ethical implications for communicating about cancer through the use of visual geographic representations are discussed.

  8. Multi-Layer Visualization of Mobile Mapping Data

    Directory of Open Access Journals (Sweden)

    D. Eggert

    2013-10-01

    Full Text Available application various different visualization schemes are conceivable. This paper presents a multi-layer based visualization method, enabling fast data browsing of mobile mapping data. In contrast to systems like Google Street View the proposed visualization does not base on 360° panoramas, but on colored point clouds projected on partially translucent images. Those images are rendered as overlapping textures, preserving the depth of the recorded data and still enabling fast rendering on any kind of platform. Furthermore the proposed visualization allows the user to inspect the mobile mapping data in a panoramic fashion with an immersive depth illusion using the parallax scrolling technic.

  9. Declarative and Scalable Selection for Map Visualizations

    DEFF Research Database (Denmark)

    Kefaloukos, Pimin Konstantin Balic

    foreground layers is merited. (2) The typical map making professional has changed from a GIS specialist to a busy person with map making as a secondary skill. Today, thematic maps are produced by journalists, aid workers, amateur data enth siasts, and scientists alike. Therefore it is crucial...... that this diverse group of map makers is provided with easy-to-use and expressible thematic map design tools. Such tools should support customized selection of data for maps in scenarios where developer time is a scarce resource. (3) The Web provides access to massive data repositories for thematic maps...... based on an access log of recent requests. The results show that Glossy SQL og CVL can be used to compute cartographic selection by processing one or more complex queries in a relational database. The scalability of the approach has been verified up to half a million objects in the database. Furthermore...

  10. Visualizing the Logistic Map with a Microcontroller

    Science.gov (United States)

    Serna, Juan D.; Joshi, Amitabh

    2012-01-01

    The logistic map is one of the simplest nonlinear dynamical systems that clearly exhibits the route to chaos. In this paper, we explore the evolution of the logistic map using an open-source microcontroller connected to an array of light-emitting diodes (LEDs). We divide the one-dimensional domain interval [0,1] into ten equal parts, an associate…

  11. Visual explorations of dynamics: The standard map

    Indian Academy of Sciences (India)

    StdMap and demonstrate some of the basic phenomena of conservative dynamical .... k = 2.0 (right pane). proven [9,10]. How long do you have to iterate until the trace of the orbit settles down and no new pixels are filled? If you have a monitor with many pixels, this ... For the standard map, τ = 1, and so it twists to the right.

  12. Visualization of nonlinear kernel models in neuroimaging by sensitivity maps

    DEFF Research Database (Denmark)

    Rasmussen, P.M.; Madsen, Kristoffer H; Lund, T.E.

    There is significant current interest in decoding mental states from neuroimages. In this context kernel methods, e.g., support vector machines (SVM) are frequently adopted to learn statistical relations between patterns of brain activation and experimental conditions. In this paper we focus...... on visualization of such nonlinear kernel models. Specifically, we investigate the sensitivity map as a technique for generation of global summary maps of kernel classification methods. We illustrate the performance of the sensitivity map on functional magnetic resonance (fMRI) data based on visual stimuli. We...

  13. Visualization of nonlinear kernel models in neuroimaging by sensitivity maps

    DEFF Research Database (Denmark)

    Rasmussen, P.M.; Madsen, Kristoffer H; Lund, T.E.

    There is significant current interest in decoding mental states from neuroimages. In this context kernel methods, e.g., support vector machines (SVM) are frequently adopted to learn statistical relations between patterns of brain activation and experimental conditions. In this paper we focus...... on visualization of such nonlinear kernel models. Specifically, we investigate the sensitivity map as a technique for generation of global summary maps of kernel classification methods. We illustrate the performance of the sensitivity map on functional magnetic resonance (fMRI) data based on visual stimuli. We...... discriminant, and the SVM, and conclude that the sensitivity map is a versatile and computationally efficient tool for visualization of nonlinear kernel models in neuroimaging...

  14. Mapping the route to visual awareness.

    Science.gov (United States)

    Hogendoorn, Hinze; Carlson, Thomas A; Verstraten, Frans A J

    2011-11-03

    The "neural correlate" of perceptual awareness is much sought-after. Here, we present an novel approach to the identification of possible neural correlates, in which we exploit the temporal connection that inevitably links the selection process that determines what we become aware of, and the development of awareness itself. Because the speed of selection determines when downstream processes can first become involved in generating awareness, the latency of neural processes provides a way to isolate the neural correlates of awareness. We recorded event-related potentials (ERPs) while observers carried out a visual behavioral task designed to estimate attentional selection latency. We show that within-task trial-by-trial behavioral variability in attentional selection latency correlates to trial-by-trial variability in ERP latency. This was true in a posterior contralateral region, and in central and frontal areas, thereby implicating these as waypoints along which visual information flows on the way to visual awareness.

  15. The Fungible Audio-Visual Mapping and its Experience

    Directory of Open Access Journals (Sweden)

    Adriana Sa

    2014-12-01

    Full Text Available This article draws a perceptual approach to audio-visual mapping. Clearly perceivable cause and effect relationships can be problematic if one desires the audience to experience the music. Indeed perception would bias those sonic qualities that fit previous concepts of causation, subordinating other sonic qualities, which may form the relations between the sounds themselves. The question is, how can an audio-visual mapping produce a sense of causation, and simultaneously confound the actual cause-effect relationships. We call this a fungible audio-visual mapping. Our aim here is to glean its constitution and aspect. We will report a study, which draws upon methods from experimental psychology to inform audio-visual instrument design and composition. The participants are shown several audio-visual mapping prototypes, after which we pose quantitative and qualitative questions regarding their sense of causation, and their sense of understanding the cause-effect relationships. The study shows that a fungible mapping requires both synchronized and seemingly non-related components – sufficient complexity to be confusing. As the specific cause-effect concepts remain inconclusive, the sense of causation embraces the whole. 

  16. Topomap: Topological Mapping and Navigation Based on Visual SLAM Maps

    OpenAIRE

    Blöchliger, Fabian; Fehr, Marius; Dymczyk, Marcin; Schneider, Thomas; Siegwart, Roland

    2017-01-01

    Visual robot navigation within large-scale, semistructured environments deals with various challenges such as computation intensive path planning algorithms or insufficient knowledge about traversable spaces. Moreover, many stateof-the-art navigation approaches only operate locally instead of gaining a more conceptual understanding of the planning objective. This limits the complexity of tasks a robot can accomplish and makes it harder to deal with uncertainties that are present in the contex...

  17. Visualizing infections and immune mechanisms in zebrafish

    DEFF Research Database (Denmark)

    Jørgensen, Louise von Gersdorff; Korbut, Rozalia; Mehrdana, Foojan

    , brain, internal organs), embryos are simple to genetically manipulate, the genome has been mapped, thousands of transgenic lines exist and a pair of breeders are able to produce up to 300 eggs per week making it a high-throughput but low-cost model organism. Unique tools for non-invasive in vivo imaging...... has been developed and high quality intravital microscopy can be conducted without comparison. A transparent line has also been developed where transparency is maintained throughout the lifespan of the fish facilitating in vivo visualization of e.g. the spread of fluorescence-tagged cancer cells......, immunological reactions during e.g. transplant rejections or the spread and pathogenicity of pathogens. We have, in our laboratory, used the zebrafish as a model for aquacultured fish species and their pathogens. We have 1) visualized antigen uptake in vivo following a bath in a soup containing fluorescent...

  18. Visualization of Disciplinary Profiles: Enhanced Science Overlay Maps

    Directory of Open Access Journals (Sweden)

    Stephen Carley

    2017-08-01

    Full Text Available Purpose: The purpose of this study is to modernize previous work on science overlay maps by updating the underlying citation matrix, generating new clusters of scientific disciplines, enhancing visualizations, and providing more accessible means for analysts to generate their own maps. Design/methodology/approach: We use the combined set of 2015 Journal Citation Reports for the Science Citation Index (n of journals = 8,778 and the Social Sciences Citation Index (n = 3,212 for a total of 11,365 journals. The set of Web of Science Categories in the Science Citation Index and the Social Sciences Citation Index increased from 224 in 2010 to 227 in 2015. Using dedicated software, a matrix of 227 × 227 cells is generated on the basis of whole-number citation counting. We normalize this matrix using the cosine function. We first develop the citing-side, cosine-normalized map using 2015 data and VOSviewer visualization with default parameter values. A routine for making overlays on the basis of the map (“wc15.exe” is available at http://www.leydesdorff.net/wc15/index.htm. Findings: Findings appear in the form of visuals throughout the manuscript. In Figures 1–9 we provide basemaps of science and science overlay maps for a number of companies, universities, and technologies. Research limitations: As Web of Science Categories change and/or are updated so is the need to update the routine we provide. Also, to apply the routine we provide users need access to the Web of Science. Practical implications: Visualization of science overlay maps is now more accurate and true to the 2015 Journal Citation Reports than was the case with the previous version of the routine advanced in our paper. Originality/value: The routine we advance allows users to visualize science overlay maps in VOSviewer using data from more recent Journal Citation Reports.

  19. ReconMap: an interactive visualization of human metabolism.

    Science.gov (United States)

    Noronha, Alberto; Daníelsdóttir, Anna Dröfn; Gawron, Piotr; Jóhannsson, Freyr; Jónsdóttir, Soffía; Jarlsson, Sindri; Gunnarsson, Jón Pétur; Brynjólfsson, Sigurður; Schneider, Reinhard; Thiele, Ines; Fleming, Ronan M T

    2017-02-15

    A genome-scale reconstruction of human metabolism, Recon 2, is available but no interface exists to interactively visualize its content integrated with omics data and simulation results. We manually drew a comprehensive map, ReconMap 2.0, that is consistent with the content of Recon 2. We present it within a web interface that allows content query, visualization of custom datasets and submission of feedback to manual curators. ReconMap can be accessed via http://vmh.uni.lu , with network export in a Systems Biology Graphical Notation compliant format released under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. A Constraint-Based Reconstruction and Analysis (COBRA) Toolbox extension to interact with ReconMap is available via https://github.com/opencobra/cobratoolbox . ronan.mt.fleming@gmail.com.

  20. Iterative fragmentation of cognitive maps in a visual imagery task.

    Science.gov (United States)

    Fourtassi, Maryam; Hajjioui, Abderrazak; Urquizar, Christian; Rossetti, Yves; Rode, Gilles; Pisella, Laure

    2013-01-01

    It remains unclear whether spontaneous eye movements during visual imagery reflect the mental generation of a visual image (i.e. the arrangement of the component parts of a mental representation). To address this specificity, we recorded eye movements in an imagery task and in a phonological fluency (non-imagery) task, both consisting in naming French towns from long-term memory. Only in the condition of visual imagery the spontaneous eye positions reflected the geographic position of the towns evoked by the subjects. This demonstrates that eye positions closely reflect the mapping of mental images. Advanced analysis of gaze positions using the bi-dimensional regression model confirmed the spatial correlation of gaze and towns' locations in every single individual in the visual imagery task and in none of the individuals when no imagery accompanied memory retrieval. In addition, the evolution of the bi-dimensional regression's coefficient of determination revealed, in each individual, a process of generating several iterative series of a limited number of towns mapped with the same spatial distortion, despite different individual order of towns' evocation and different individual mappings. Such consistency across subjects revealed by gaze (the mind's eye) gives empirical support to theories postulating that visual imagery, like visual sampling, is an iterative fragmented processing.

  1. Iterative fragmentation of cognitive maps in a visual imagery task.

    Directory of Open Access Journals (Sweden)

    Maryam Fourtassi

    Full Text Available It remains unclear whether spontaneous eye movements during visual imagery reflect the mental generation of a visual image (i.e. the arrangement of the component parts of a mental representation. To address this specificity, we recorded eye movements in an imagery task and in a phonological fluency (non-imagery task, both consisting in naming French towns from long-term memory. Only in the condition of visual imagery the spontaneous eye positions reflected the geographic position of the towns evoked by the subjects. This demonstrates that eye positions closely reflect the mapping of mental images. Advanced analysis of gaze positions using the bi-dimensional regression model confirmed the spatial correlation of gaze and towns' locations in every single individual in the visual imagery task and in none of the individuals when no imagery accompanied memory retrieval. In addition, the evolution of the bi-dimensional regression's coefficient of determination revealed, in each individual, a process of generating several iterative series of a limited number of towns mapped with the same spatial distortion, despite different individual order of towns' evocation and different individual mappings. Such consistency across subjects revealed by gaze (the mind's eye gives empirical support to theories postulating that visual imagery, like visual sampling, is an iterative fragmented processing.

  2. Mapping Design Students' Aesthetic and Visual Preference

    DEFF Research Database (Denmark)

    Raahauge, Kirsten Marie; Ohrt, Ann Merete

    2016-01-01

    is to compare and map cultural differences, similarities and preferences in young designers design approach in order to understand how globalization and localization influence design. It is also the purpose to investigate how different teaching methods influence the way the young designers understand......The overall purpose of our research is to investigate young designers design processes and methods on a global scale, by conducting a series of workshops at selected design universities in among others Taiwan, China, Brazil, South Africa, India and Russia. The focus of the research project......, identity, and cultural codes. The workshops are documented, analysed and compared in order to get a better understanding of how, and if, different universities’ learning methods and cultural backgrounds influence the students’ design approaches, practices and conceptions. In this way we hope to broaden...

  3. Concept Maps as Cognitive Visualizations of Writing Assignments

    Science.gov (United States)

    Villalon, Jorge; Calvo, Rafael A.

    2011-01-01

    Writing assignments are ubiquitous in higher education. Writing develops not only communication skills, but also higher-level cognitive processes that facilitate deep learning. Cognitive visualizations, such as concept maps, can also be used as part of learning activities including as a form of scaffolding, or to trigger reflection by making…

  4. Visualization of nonlinear kernel models in neuroimaging by sensitivity maps

    DEFF Research Database (Denmark)

    Rasmussen, Peter Mondrup; Madsen, Kristoffer Hougaard; Lund, Torben Ellegaard

    2011-01-01

    that the performance of linear models is reduced for certain scan labelings/categorizations in this data set, while the nonlinear models provide more flexibility. We show that the sensitivity map can be used to visualize nonlinear versions of kernel logistic regression, the kernel Fisher discriminant, and the SVM...

  5. A General Framework for Dimensionality-Reducing Data Visualization Mapping

    NARCIS (Netherlands)

    Bunte, Kerstin; Biehl, Michael; Hammer, Barbara

    In recent years, a wealth of dimension-reduction techniques for data visualization and preprocessing has been established. Nonparametric methods require additional effort for out-of-sample extensions, because they provide only a mapping of a given finite set of points. In this letter, we propose a

  6. Learning indoor robot navigation using visual and sensorimotor map information

    Science.gov (United States)

    Yan, Wenjie; Weber, Cornelius; Wermter, Stefan

    2013-01-01

    As a fundamental research topic, autonomous indoor robot navigation continues to be a challenge in unconstrained real-world indoor environments. Although many models for map-building and planning exist, it is difficult to integrate them due to the high amount of noise, dynamics, and complexity. Addressing this challenge, this paper describes a neural model for environment mapping and robot navigation based on learning spatial knowledge. Considering that a person typically moves within a room without colliding with objects, this model learns the spatial knowledge by observing the person's movement using a ceiling-mounted camera. A robot can plan and navigate to any given position in the room based on the acquired map, and adapt it based on having identified possible obstacles. In addition, salient visual features are learned and stored in the map during navigation. This anchoring of visual features in the map enables the robot to find and navigate to a target object by showing an image of it. We implement this model on a humanoid robot and tests are conducted in a home-like environment. Results of our experiments show that the learned sensorimotor map masters complex navigation tasks. PMID:24109451

  7. Facial motion engages predictive visual mechanisms.

    Directory of Open Access Journals (Sweden)

    Jordy Kaufman

    Full Text Available We employed a novel cuing paradigm to assess whether dynamically versus statically presented facial expressions differentially engaged predictive visual mechanisms. Participants were presented with a cueing stimulus that was either the static depiction of a low intensity expressed emotion; or a dynamic sequence evolving from a neutral expression to the low intensity expressed emotion. Following this cue and a backwards mask, participants were presented with a probe face that displayed either the same emotion (congruent or a different emotion (incongruent with respect to that displayed by the cue although expressed at a high intensity. The probe face had either the same or different identity from the cued face. The participants' task was to indicate whether or not the probe face showed the same emotion as the cue. Dynamic cues and same identity cues both led to a greater tendency towards congruent responding, although these factors did not interact. Facial motion also led to faster responding when the probe face was emotionally congruent to the cue. We interpret these results as indicating that dynamic facial displays preferentially invoke predictive visual mechanisms, and suggest that motoric simulation may provide an important basis for the generation of predictions in the visual system.

  8. Modeling and visualizing uncertainty in digital thematic maps

    Science.gov (United States)

    Prasad, M. S. Ganesh; Arora, M. K.; Sajith, V. K.

    2006-12-01

    Spatial data in the form of thematic maps produced from remote sensing images are widely used in many application areas such as hydrology, geology, disaster management, forestry etc. These maps inherently contain uncertainties due to various reasons. The presence of uncertainty in thematic maps degrades the quality of maps and subsequently affects the decisions based on these data. Traditional way of quantifying quality is to compute the overall accuracy of the map, which however does not depict the spatial distribution of quality of whole map. It would be more expedient to use pixel-wise uncertainty as a means of quality indicator of a thematic map. This can be achieved through a number of mathematical tools based on well known theories of probability, geo-statistics, fuzzy sets and rough sets. Information theory and theory of evidence may also be adopted in this context. Nevertheless, there are several challenges involved in characterizing and providing uncertainty information to the users through these theories. The aim of this paper is to apprise the users of remote sensing about the uncertainties present in the thematic maps and to suggest ways to adequately deal with these uncertainties through proper modeling and visualization. Quantification and proper representation of uncertainty to the users may lead to increase in their confidence in using remote sensing derived products.

  9. LOD map--A visual interface for navigating multiresolution volume visualization.

    Science.gov (United States)

    Wang, Chaoli; Shen, Han-Wei

    2006-01-01

    In multiresolution volume visualization, a visual representation of level-of-detail (LOD) quality is important for us to examine, compare, and validate different LOD selection algorithms. While traditional methods rely on ultimate images for quality measurement, we introduce the LOD map--an alternative representation of LOD quality and a visual interface for navigating multiresolution data exploration. Our measure for LOD quality is based on the formulation of entropy from information theory. The measure takes into account the distortion and contribution of multiresolution data blocks. A LOD map is generated through the mapping of key LOD ingredients to a treemap representation. The ordered treemap layout is used for relative stable update of the LOD map when the view or LOD changes. This visual interface not only indicates the quality of LODs in an intuitive way, but also provides immediate suggestions for possible LOD improvement through visually-striking features. It also allows us to compare different views and perform rendering budget control. A set of interactive techniques is proposed to make the LOD adjustment a simple and easy task. We demonstrate the effectiveness and efficiency of our approach on large scientific and medical data sets.

  10. Data visualization in interactive maps and time series

    Science.gov (United States)

    Maigne, Vanessa; Evano, Pascal; Brockmann, Patrick; Peylin, Philippe; Ciais, Philippe

    2014-05-01

    State-of-the-art data visualization has nothing to do with plots and maps we used few years ago. Many opensource tools are now available to provide access to scientific data and implement accessible, interactive, and flexible web applications. Here we will present a web site opened November 2013 to create custom global and regional maps and time series from research models and datasets. For maps, we explore and get access to data sources from a THREDDS Data Server (TDS) with the OGC WMS protocol (using the ncWMS implementation) then create interactive maps with the OpenLayers javascript library and extra information layers from a GeoServer. Maps become dynamic, zoomable, synchroneaously connected to each other, and exportable to Google Earth. For time series, we extract data from a TDS with the Netcdf Subset Service (NCSS) then display interactive graphs with a custom library based on the Data Driven Documents javascript library (D3.js). This time series application provides dynamic functionalities such as interpolation, interactive zoom on different axes, display of point values, and export to different formats. These tools were implemented for the Global Carbon Atlas (http://www.globalcarbonatlas.org): a web portal to explore, visualize, and interpret global and regional carbon fluxes from various model simulations arising from both human activities and natural processes, a work led by the Global Carbon Project.

  11. Computer-Assisted Concept Mapping: Visual Aids for Knowledge Construction.

    Science.gov (United States)

    Mammen, Jennifer R

    2016-07-01

    Concept mapping is a visual representation of ideas that facilitates critical thinking and is applicable to many areas of nursing education. Computer-assisted concept maps are more flexible and less constrained than traditional paper methods, allowing for analysis and synthesis of complex topics and larger amounts of data. Ability to iteratively revise and collaboratively create computerized maps can contribute to enhanced interpersonal learning. However, there is limited awareness of free software that can support these types of applications. This educational brief examines affordances and limitations of computer-assisted concept maps and reviews free software for development of complex, collaborative malleable maps. Free software, such as VUE, XMind, MindMaple, and others, can substantially contribute to the utility of concept mapping for nursing education. Computerized concept-mapping is an important tool for nursing and is likely to hold greater benefit for students and faculty than traditional pen-and-paper methods alone. [J Nurs Educ. 2016;55(7):403-406.]. Copyright 2016, SLACK Incorporated.

  12. Researchermap: a tool for visualizing author locations using Google maps.

    Science.gov (United States)

    Rastegar-Mojarad, Majid; Bales, Michael E; Yu, Hong

    2013-01-01

    We hereby present ResearcherMap, a tool to visualize locations of authors of scholarly papers. In response to a query, the system returns a map of author locations. To develop the system we first populated a database of author locations, geocoding institution locations for all available institutional affiliation data in our database. The database includes all authors of Medline papers from 1990 to 2012. We conducted a formative heuristic usability evaluation of the system and measured the system's accuracy and performance. The accuracy of finding the accurate address is 97.5% in our system.

  13. Flattening maps for the visualization of multibranched vessels.

    Science.gov (United States)

    Zhu, Lei; Haker, Steven; Tannenbaum, Allen

    2005-02-01

    In this paper, we present two novel algorithms which produce flattened visualizations of branched physiological surfaces, such as vessels. The first approach is a conformal mapping algorithm based on the minimization of two Dirichlet functionals. From a triangulated representation of vessel surfaces, we show how the algorithm can be implemented using a finite element technique. The second method is an algorithm which adjusts the conformal mapping to produce a flattened representation of the original surface while preserving areas. This approach employs the theory of optimal mass transport. Furthermore, a new way of extracting center lines for vessel fly-throughs is provided.

  14. Mapping scientific frontiers : the quest for knowledge visualization.

    Energy Technology Data Exchange (ETDEWEB)

    Boyack, Kevin W.

    2003-08-01

    Visualization of scientific frontiers is a relatively new field, yet it has a long history and many predecessors. The application of science to science itself has been undertaken for decades with notable early contributions by Derek Price, Thomas Kuhn, Diana Crane, Eugene Garfield, and many others. What is new is the field of information visualization and application of its techniques to help us understand the process of science in the making. In his new book, Chaomei Chen takes us on a journey through this history, touching on predecessors, and then leading us firmly into the new world of Mapping Scientific Frontiers. Building on the foundation of his earlier book, Information Visualization and Virtual Environments, Chen's new offering is much less a tutorial in how to do information visualization, and much more a conceptual exploration of why and how the visualization of science can change the way we do science, amplified by real examples. Chen's stated intents for the book are: (1) to focus on principles of visual thinking that enable the identification of scientific frontiers; (2) to introduce a way to systematize the identification of scientific frontiers (or paradigms) through visualization techniques; and (3) to stimulate interdisciplinary research between information visualization and information science researchers. On all these counts, he succeeds. Chen's book can be broken into two parts which focus on the first two purposes stated above. The first, consisting of the initial four chapters, covers history and predecessors. Kuhn's theory of normal science punctuated by periods of revolution, now commonly known as paradigm shifts, motivates the work. Relevant predecessors outside the traditional field of information science such as cartography (both terrestrial and celestial), mapping the mind, and principles of visual association and communication, are given ample coverage. Chen also describes enabling techniques known to information

  15. Fiber Visualization with LIC Maps Using Multidirectional Anisotropic Glyph Samples

    Directory of Open Access Journals (Sweden)

    Mark Höller

    2014-01-01

    Full Text Available Line integral convolution (LIC is used as a texture-based technique in computer graphics for flow field visualization. In diffusion tensor imaging (DTI, LIC bridges the gap between local approaches, for example directionally encoded fractional anisotropy mapping and techniques analyzing global relationships between brain regions, such as streamline tracking. In this paper an advancement of a previously published multikernel LIC approach for high angular resolution diffusion imaging visualization is proposed: a novel sampling scheme is developed to generate anisotropic glyph samples that can be used as an input pattern to the LIC algorithm. Multicylindrical glyph samples, derived from fiber orientation distribution (FOD functions, are used, which provide a method for anisotropic packing along integrated fiber lines controlled by a uniform random algorithm. This allows two- and three-dimensional LIC maps to be generated, depicting fiber structures with excellent contrast, even in regions of crossing and branching fibers. Furthermore, a color-coding model for the fused visualization of slices from T1 datasets together with directionally encoded LIC maps is proposed. The methodology is evaluated by a simulation study with a synthetic dataset, representing crossing and bending fibers. In addition, results from in vivo studies with a healthy volunteer and a brain tumor patient are presented to demonstrate the method's practicality.

  16. Visualization of Nonlinear Classification Models in Neuroimaging - Signed Sensitivity Maps

    DEFF Research Database (Denmark)

    Rasmussen, Peter Mondrup; Schmah, Tanya; Madsen, Kristoffer H

    2012-01-01

    visualization. Specifically we focus on the generation of summary maps of a nonlinear classifier, that reveal how the classifier works in different parts of the input domain. Each of the maps includes sign information, unlike earlier related methods. The sign information allows the researcher to assess in which......Classification models are becoming increasing popular tools in the analysis of neuroimaging data sets. Besides obtaining good prediction accuracy, a competing goal is to interpret how the classifier works. From a neuroscientific perspective, we are interested in the brain pattern reflecting...... the underlying neural encoding of an experiment defining multiple brain states. In this relation there is a great desire for the researcher to generate brain maps, that highlight brain locations of importance to the classifiers decisions. Based on sensitivity analysis, we develop further procedures for model...

  17. Venus Quadrangle Geological Mapping: Use of Geoscience Data Visualization Systems in Mapping and Training

    Science.gov (United States)

    Head, James W.; Huffman, J. N.; Forsberg, A. S.; Hurwitz, D. M.; Basilevsky, A. T.; Ivanov, M. A.; Dickson, J. L.; Kumar, P. Senthil

    2008-01-01

    We are currently investigating new technological developments in computer visualization and analysis in order to assess their importance and utility in planetary geological analysis and mapping [1,2]. Last year we reported on the range of technologies available and on our application of these to various problems in planetary mapping [3]. In this contribution we focus on the application of these techniques and tools to Venus geological mapping at the 1:5M quadrangle scale. In our current Venus mapping projects we have utilized and tested the various platforms to understand their capabilities and assess their usefulness in defining units, establishing stratigraphic relationships, mapping structures, reaching consensus on interpretations and producing map products. We are specifically assessing how computer visualization display qualities (e.g., level of immersion, stereoscopic vs. monoscopic viewing, field of view, large vs. small display size, etc.) influence performance on scientific analysis and geological mapping. We have been exploring four different environments: 1) conventional desktops (DT), 2) semi-immersive Fishtank VR (FT) (i.e., a conventional desktop with head-tracked stereo and 6DOF input), 3) tiled wall displays (TW), and 4) fully immersive virtual reality (IVR) (e.g., "Cave Automatic Virtual Environment," or Cave system). Formal studies demonstrate that fully immersive Cave environments are superior to desktop systems for many tasks [e.g., 4].

  18. Visual Fast Mapping in School-Aged Children with Specific Language Impairment

    Science.gov (United States)

    Alt, Mary

    2013-01-01

    Purpose: To determine whether children with specific language impairment (SLI) demonstrate impaired visual fast mapping skills compared with unimpaired peers and to test components of visual working memory that may contribute to a visual working memory deficit. Methods: Fifty children (25 SLI) played 2 computer-based visual fast mapping games…

  19. Choropleth map legend design for visualizing community health disparities

    Directory of Open Access Journals (Sweden)

    Cromley Ellen K

    2009-09-01

    Full Text Available Abstract Background Disparities in health outcomes across communities are a central concern in public health and epidemiology. Health disparities research often links differences in health outcomes to other social factors like income. Choropleth maps of health outcome rates show the geographical distribution of health outcomes. This paper illustrates the use of cumulative frequency map legends for visualizing how the health events are distributed in relation to social characteristics of community populations. The approach uses two graphs in the cumulative frequency legend to highlight the difference between the raw count of the health events and the raw count of the social characteristic like low income in the geographical areas of the map. The approach is applied to mapping publicly available data on low birth weight by town in Connecticut and Lyme disease incidence by town in Connecticut in relation to income. The steps involved in creating these legends are described in detail so that health analysts can adopt this approach. Results The different health problems, low birth weight and Lyme disease, have different cumulative frequency signatures. Graphing poverty population on the cumulative frequency legends revealed that the poverty population is distributed differently with respect to the two different health problems mapped here. Conclusion Cumulative frequency legends can be useful supplements for choropleth maps. These legends can be constructed using readily available software. They contain all of the information found in standard choropleth map legends, and they can be used with any choropleth map classification scheme. Cumulative frequency legends effectively communicate the proportion of areas, the proportion of health events, and/or the proportion of the denominator population in which the health events occurred that falls within each class interval. They illuminate the context of disease through graphing associations with other

  20. Visual cortex in aging and Alzheimer's disease: changes in visual field maps and population receptive fields

    Science.gov (United States)

    Brewer, Alyssa A.; Barton, Brian

    2012-01-01

    Although several studies have suggested that cortical alterations underlie such age-related visual deficits as decreased acuity, little is known about what changes actually occur in visual cortex during healthy aging. Two recent studies showed changes in primary visual cortex (V1) during normal aging; however, no studies have characterized the effects of aging on visual cortex beyond V1, important measurements both for understanding the aging process and for comparison to changes in age-related diseases. Similarly, there is almost no information about changes in visual cortex in Alzheimer's disease (AD), the most common form of dementia. Because visual deficits are often reported as one of the first symptoms of AD, measurements of such changes in the visual cortex of AD patients might improve our understanding of how the visual system is affected by neurodegeneration as well as aid early detection, accurate diagnosis and timely treatment of AD. Here we use fMRI to first compare the visual field map (VFM) organization and population receptive fields (pRFs) between young adults and healthy aging subjects for occipital VFMs V1, V2, V3, and hV4. Healthy aging subjects do not show major VFM organizational deficits, but do have reduced surface area and increased pRF sizes in the foveal representations of V1, V2, and hV4 relative to healthy young control subjects. These measurements are consistent with behavioral deficits seen in healthy aging. We then demonstrate the feasibility and first characterization of these measurements in two patients with mild AD, which reveal potential changes in visual cortex as part of the pathophysiology of AD. Our data aid in our understanding of the changes in the visual processing pathways in normal aging and provide the foundation for future research into earlier and more definitive detection of AD. PMID:24570669

  1. Mapping the mosaic sequence of primate visual cortical development

    Directory of Open Access Journals (Sweden)

    Inaki-Carril eMundinano

    2015-10-01

    Full Text Available Traditional ‘textbook’ theory suggests that the development and maturation of visual cortical areas occur as a wave from V1. However, more recent evidence would suggest that this is not the case, and the emergence of extrastriate areas occurs in a non-hierarchical fashion. This proposition comes from both physiological and anatomical studies but the actual developmental sequence of extrastriate areas remains unknown. In the current study, we examined the development and maturation of the visual cortex of the marmoset monkey, a New World simian, from embryonic day 130 (15 days prior to birth through to adulthood. Utilizing the well-described expression characteristics of the calcium-binding proteins calbindin and parvalbumin, and nonphosphorylated neurofilament for the pyramidal neurons, we were able to accurately map the sequence of development and maturation of the visual cortex. To this end, we demonstrated that both V1 and middle temporal area (MT emerge first and that MT likely supports dorsal stream development while V1 supports ventral stream development. Furthermore, the emergence of the dorsal stream-associated areas was significantly earlier than ventral stream areas. The difference in the temporal development of the visual streams is likely driven by a teleological requirement for specific visual behavior in early life.

  2. Visual Experience Is Required for the Development of Eye Movement Maps in the Mouse Superior Colliculus.

    Science.gov (United States)

    Wang, Lupeng; Liu, Mingna; Segraves, Mark A; Cang, Jianhua

    2015-09-02

    Topographic maps are a fundamental feature of the brain's representations of the sensory environment as well as an efficient way to organize motor control networks. Although great progress has been made in our understanding of sensory map development, very little is known about how topographic representations for motor control develop and interface with sensory maps. Here we map the representation for eye movements in the superior colliculus (SC) in awake mice. As stimulation sites were sampled along the anterior-posterior axis, small amplitude, nasally directed (ipsiversive) saccadic eye movements were evoked by microstimulation in anterior SC, followed by a smooth progression to large, temporally directed (contraversive) movements in posterior SC. This progressive change of movement amplitude and direction is consistent with the global polarity of the retinotopic map in the superficial SC, just as in primates and cats. We then investigated the role of visual experience in the development of eye movement map by studying mice reared in complete darkness. Saccades evoked by SC stimulation as well as spontaneous saccadic eye movements were larger in the dark-reared mice, indicating that visual experience is required to fine-tune the gain of saccades and to establish normal eye movement maps in the SC. Our experiments provide a foundation for future studies to investigate the synaptic organization and developmental mechanisms of sensorimotor transformations in mice. The superior colliculus (SC) is a midbrain structure important for multisensory integration and sensorimotor transformation. Here we have studied eye movement representations in the SC of mice, a species that has become a popular model in vision research because of available genetic tools. Our studies show mice make saccadic eye movements spontaneously and in response to SC stimulation. The mouse SC contains an eye movement map that has the same global polarity as the overlaying visual map, just like in

  3. [Digital administrative maps - a tool for visualization of epidemiological data].

    Science.gov (United States)

    Niewiadomska, Ewa; Kowalska, Malgorzata; Czech, Elibieta; Skrzypek, Michal

    2013-01-01

    The aim of the study is to present the methods for visualization of epidemiological data using digital contour maps that take into account administrative division of Poland. The possibility of epidemiological data visualization in a geographical order, limited to the administrative level of the country, voivodeships and poviats (countics), are presented. They are crucial for the process of identifying and undertaking adequate prophylactic activities directed towards decreasing the risk and improving the population's health. This paper presents tools and techniques available in Geographic Information System ArcGIS and statistical software package R. The work includes our own data reflecting: 1) the values of specific mortality rates due to respiratory diseases, Poland, 2010, based on the Central Statistical Office data, using the R statistical software package; 2) the averaged registered incidence rates of sarcoidosis in 2006-2010 for the population aged 19+ in the Silesian voivodeship, using G(eographic Information System ArcGIS; and 3) the number of children with diagnosed respiratory diseases in the city of L.egnica in 2009, taking into account their place of residence, using layered maps in Geographic Information System ArcGIS. The tools presented and described in this paper make it possible to visualize the results of research, to increase attractiveness of courses for students, as well as to enhance the skills and competence of students and participants of courses.

  4. A Visual-Aided Inertial Navigation and Mapping System

    Directory of Open Access Journals (Sweden)

    Rodrigo Munguía

    2016-05-01

    Full Text Available State estimation is a fundamental necessity for any application involving autonomous robots. This paper describes a visual-aided inertial navigation and mapping system for application to autonomous robots. The system, which relies on Kalman filtering, is designed to fuse the measurements obtained from a monocular camera, an inertial measurement unit (IMU and a position sensor (GPS. The estimated state consists of the full state of the vehicle: the position, orientation, their first derivatives and the parameter errors of the inertial sensors (i.e., the bias of gyroscopes and accelerometers. The system also provides the spatial locations of the visual features observed by the camera. The proposed scheme was designed by considering the limited resources commonly available in small mobile robots, while it is intended to be applied to cluttered environments in order to perform fully vision-based navigation in periods where the position sensor is not available. Moreover, the estimated map of visual features would be suitable for multiple tasks: i terrain analysis; ii three-dimensional (3D scene reconstruction; iii localization, detection or perception of obstacles and generating trajectories to navigate around these obstacles; and iv autonomous exploration. In this work, simulations and experiments with real data are presented in order to validate and demonstrate the performance of the proposal.

  5. Functional implications of orientation maps in primary visual cortex

    Science.gov (United States)

    Koch, Erin; Jin, Jianzhong; Alonso, Jose M.; Zaidi, Qasim

    2016-11-01

    Stimulus orientation in the primary visual cortex of primates and carnivores is mapped as iso-orientation domains radiating from pinwheel centres, where orientation preferences of neighbouring cells change circularly. Whether this orientation map has a function is currently debated, because many mammals, such as rodents, do not have such maps. Here we show that two fundamental properties of visual cortical responses, contrast saturation and cross-orientation suppression, are stronger within cat iso-orientation domains than at pinwheel centres. These differences develop when excitation (not normalization) from neighbouring oriented neurons is applied to different cortical orientation domains and then balanced by inhibition from un-oriented neurons. The functions of the pinwheel mosaic emerge from these local intra-cortical computations: Narrower tuning, greater cross-orientation suppression and higher contrast gain of iso-orientation cells facilitate extraction of object contours from images, whereas broader tuning, greater linearity and less suppression of pinwheel cells generate selectivity for surface patterns and textures.

  6. Evolution of attention mechanisms for early visual processing

    Science.gov (United States)

    Müller, Thomas; Knoll, Alois

    2011-03-01

    Early visual processing as a method to speed up computations on visual input data has long been discussed in the computer vision community. The general target of a such approaches is to filter nonrelevant information from the costly higher-level visual processing algorithms. By insertion of this additional filter layer the overall approach can be speeded up without actually changing the visual processing methodology. Being inspired by the layered architecture of the human visual processing apparatus, several approaches for early visual processing have been recently proposed. Most promising in this field is the extraction of a saliency map to determine regions of current attention in the visual field. Such saliency can be computed in a bottom-up manner, i.e. the theory claims that static regions of attention emerge from a certain color footprint, and dynamic regions of attention emerge from connected blobs of textures moving in a uniform way in the visual field. Top-down saliency effects are either unconscious through inherent mechanisms like inhibition-of-return, i.e. within a period of time the attention level paid to a certain region automatically decreases if the properties of that region do not change, or volitional through cognitive feedback, e.g. if an object moves consistently in the visual field. These bottom-up and top-down saliency effects have been implemented and evaluated in a previous computer vision system for the project JAST. In this paper an extension applying evolutionary processes is proposed. The prior vision system utilized multiple threads to analyze the regions of attention delivered from the early processing mechanism. Here, in addition, multiple saliency units are used to produce these regions of attention. All of these saliency units have different parameter-sets. The idea is to let the population of saliency units create regions of attention, then evaluate the results with cognitive feedback and finally apply the genetic mechanism

  7. Mapping arealisation of the visual cortex of non-primate species: lessons for development and evolution

    Directory of Open Access Journals (Sweden)

    Jihane eHomman-Ludiye

    2014-07-01

    Full Text Available In order to integrate and interpret visual stimuli and build a representation of the surrounding environment, the visual cortex is organised in anatomically distinct and functionally unique areas. Each area processes a particular aspect of the visual scene, with the signal flowing from one area to the next in a bottom-up processing sequence. Areal borders can be demarcated both functionally by systematic electrophysiology mapping, and anatomically by sharp changes in cellular distribution and molecular expression profiles. Primates, including humans, are heavily dependent on vision, with approximately 50% of their neocortical surface dedicated to visual processing and possess many more visual areas than any other mammal, making them often the model of choice to study visual arealisation. However, the recent identification of differential gene expression profiles between cortices in a number of species has allowed for the introduction of non-primate animal models in the field to better understand development and evolution. Profiling the mosaic of visual areas in less complex species was pivotal in understanding the mechanisms responsible for patterning the developing neocortex, specifying area identity as well as the evolutionary events that have allowed for primates to develop more areas. In addition, species with fewer areas provide a simpler system in which to study and map cortical connectivity. In this review we focus on non-primate species that have contributed to elucidating the evolution and development of the visual cortex, including small nocturnal species and carnivores. We present the current understanding of the mechanisms supporting the establishment of areal borders during development and the limitations of the predominant mouse model and the need for alternate species.

  8. A proto-architecture for innate directionally selective visual maps.

    Directory of Open Access Journals (Sweden)

    Samantha V Adams

    Full Text Available Self-organizing artificial neural networks are a popular tool for studying visual system development, in particular the cortical feature maps present in real systems that represent properties such as ocular dominance (OD, orientation-selectivity (OR and direction selectivity (DS. They are also potentially useful in artificial systems, for example robotics, where the ability to extract and learn features from the environment in an unsupervised way is important. In this computational study we explore a DS map that is already latent in a simple artificial network. This latent selectivity arises purely from the cortical architecture without any explicit coding for DS and prior to any self-organising process facilitated by spontaneous activity or training. We find DS maps with local patchy regions that exhibit features similar to maps derived experimentally and from previous modeling studies. We explore the consequences of changes to the afferent and lateral connectivity to establish the key features of this proto-architecture that support DS.

  9. Research and development productivity map: visualization of industry status.

    Science.gov (United States)

    Shimura, H; Masuda, S; Kimura, H

    2014-04-01

    Decline in research and development (R&D) productivity and changes in the business environment have led to pharmaceutical company management to strive to improve R&D productivity. This decline is widely considered to be a major cause of industry consolidation and has received increased scholarly attention. This study aims to construct an R&D productivity map to visualize the industry's R&D productivity and to identify similarity in corporate actions with a view to investigate whether there is a relationship between deterioration in R&D productivity and industry consolidation. Research and development productivity is decomposed into two subprocesses to measure productivity: R&D efficiency and R&D effectiveness, and scores were calculated using a two-stage data envelopment analysis (DEA). The map is then constructed by projecting outputs. To identify any relationship between DEA scores and merger and acquisition transactions, a multiple regression model is employed. Data on 21 global pharmaceutical companies, statistical results indicated that companies with lower R&D efficiency scores were more likely to engage in consolidation. Three US companies that were least successful in terms of R&D effectiveness, as measured by our indicators, were either acquired or changed their business model. The R&D productivity map is a useful means for visualizing productivity among companies. By grouping companies into four groups, behavioural commonalities can be observed. The R&D productivity map should be useful for monitor the industry's productivity and help to improve it. © 2014 John Wiley & Sons Ltd.

  10. Mechanisms for Visual Detection of Small Targets in Insects

    Science.gov (United States)

    2009-12-01

    AOARD-09-4058 / FA2386-09-1-4058 Mechanisms for Visual Detection of Small Targets in Insects Final Performance Report December 1, 2009...SUBTITLE Mechanisms for Visual Detection of Small Targets in Insects 5a. CONTRACT NUMBER FA23860914058 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...grantee investigated insect visual detection of small targets against a cluttered, moving background. The work focused on deducing neural mechanisms

  11. Testing geoscience data visualization systems for geological mapping and training

    Science.gov (United States)

    Head, J. W.; Huffman, J. N.; Forsberg, A. S.; Hurwitz, D. M.; Basilevsky, A. T.; Ivanov, M. A.; Dickson, J. L.; Senthil Kumar, P.

    2008-09-01

    Traditional methods of planetary geological mapping have relied on photographic hard copy and light-table tracing and mapping. In the last several decades this has given way to the availability and analysis of multiple digital data sets, and programs and platforms that permit the viewing and manipulation of multiple annotated layers of relevant information. This has revolutionized the ability to incorporate important new data into the planetary mapping process at all scales. Information on these developments and approaches can be obtained at http://astrogeology.usgs. gov/ Technology/. The processes is aided by Geographic Information Systems (GIS) (see http://astrogeology. usgs.gov/Technology/) and excellent analysis packages (such as ArcGIS) that permit co-registration, rapid viewing, and analysis of multiple data sets on desktop displays (see http://astrogeology.usgs.gov/Projects/ webgis/). We are currently investigating new technological developments in computer visualization and analysis in order to assess their importance and utility in planetary geological analysis and mapping. Last year we reported on the range of technologies available and on our application of these to various problems in planetary mapping. In this contribution we focus on the application of these techniques and tools to Venus geological mapping at the 1:5M quadrangle scale. In our current Venus mapping projects we have utilized and tested the various platforms to understand their capabilities and assess their usefulness in defining units, establishing stratigraphic relationships, mapping structures, reaching consensus on interpretations and producing map products. We are specifically assessing how computer visualization display qualities (e.g., level of immersion, stereoscopic vs. monoscopic viewing, field of view, large vs. small display size, etc.) influence performance on scientific analysis and geological mapping. We have been exploring four different environments: 1) conventional

  12. Satellite Data Visualization, Processing and Mapping using VIIRS Imager Data

    Science.gov (United States)

    Phyu, A. N.

    2016-12-01

    A satellite is a manmade machine that is launched into space and orbits the Earth. These satellites are used for various purposes for examples: Environmental satellites help us monitor and protect our environment; Navigation (GPS) satellites provides accurate time and position information: and Communication satellites allows us the interact with each other over long distances. Suomi NPP is part of the constellation of Joint Polar Satellite System (JPSS) fleet of satellites which is an Environmental satellite that carries the Visual Infrared Imaging Radiometer Suite (VIIRS) instrument. VIIRS is a scanning radiometer that takes high resolution images of the Earth. VIIRS takes visible, infrared and radiometric measurements of the land, oceans, atmosphere and cryosphere. These high resolution images provide information that helps weather prediction and environmental forecasting of extreme events such as forest fires, ice jams, thunder storms and hurricane. This project will describe how VIIRS instrument data is processed, mapped, and visualized using variety of software and application. It will focus on extreme events like Hurricane Sandy and demonstrate how to use the satellite to map the extent of a storm. Data from environmental satellites such as Suomi NPP-VIIRS is important for monitoring climate change, sea level rise, land surface temperature changes as well as extreme weather events.

  13. Semantic Data And Visualization Techniques Applied To Geologic Field Mapping

    Science.gov (United States)

    Houser, P. I. Q.; Royo-Leon, M.; Munoz, R.; Estrada, E.; Villanueva-Rosales, N.; Pennington, D. D.

    2015-12-01

    Geologic field mapping involves the use of technology before, during, and after visiting a site. Geologists utilize hardware such as Global Positioning Systems (GPS) connected to mobile computing platforms such as tablets that include software such as ESRI's ArcPad and other software to produce maps and figures for a final analysis and report. Hand written field notes contain important information and drawings or sketches of specific areas within the field study. Our goal is to collect and geo-tag final and raw field data into a cyber-infrastructure environment with an ontology that allows for large data processing, visualization, sharing, and searching, aiding in connecting field research with prior research in the same area and/or aid with experiment replication. Online searches of a specific field area return results such as weather data from NOAA and QuakeML seismic data from USGS. These results that can then be saved to a field mobile device and searched while in the field where there is no Internet connection. To accomplish this we created the GeoField ontology service using the Web Ontology Language (OWL) and Protégé software. Advanced queries on the dataset can be made using reasoning capabilities can be supported that go beyond a standard database service. These improvements include the automated discovery of data relevant to a specific field site and visualization techniques aimed at enhancing analysis and collaboration while in the field by draping data over mobile views of the site using augmented reality. A case study is being performed at University of Texas at El Paso's Indio Mountains Research Station located near Van Horn, Texas, an active multi-disciplinary field study site. The user can interactively move the camera around the study site and view their data digitally. Geologist's can check their data against the site in real-time and improve collaboration with another person as both parties have the same interactive view of the data.

  14. The Classical and Quantum Mechanics of lazy baker Maps

    CERN Document Server

    Lakshminarayan, A

    1993-01-01

    We introduce and study the classical and quantum mechanics of certain non hyperbolic maps on the unit square. These maps are modifications of the usual baker's map and their behaviour ranges from chaotic motion on the whole measure to chaos on a set of measure zero. Thus we have called these maps ``lazy baker maps.'' The aim of introducing these maps is to provide the simplest models of systems with a mixed phase space, in which there are both regular and chaotic motions. We find that despite the obviously contrived nature of these maps they provide a good model for the study of the quantum mechanics of such systems. We notice the effect of a classically chaotic fractal set of measure zero on the corresponding quantum maps, which leads to a transition in the spectral statistics. Some periodic orbits belonging to this fractal set are seen to scar several eigenfunctions.

  15. Mechanism for Visual Detection of Small Targets in Insects

    Science.gov (United States)

    2013-06-14

    1 Final Report for AOARD Grant FA2386-10-1-4114 AOARD 104114 “Mechanisms for Visual Detection of Small Targets in Insects ” 14 June...Final 3. DATES COVERED 15-06-2010 to 15-12-2012 4. TITLE AND SUBTITLE Mechanism for visual detection of small targets in insects 5a. CONTRACT...unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Specialized Small Target Motion Detector Neurons (STMDs) in the optic lobes of the insect brain

  16. Visualizing sediment dynamics through repeated high-resolution multibeam mapping

    Science.gov (United States)

    de Vries, J. J.; Greinert, J.; Maierhofer, T.

    2013-12-01

    Multibeam mapping has become a common method for mapping the seafloor in shallow and great water depths with different spatial resolutions depending on the system platform (ship-based, AUV- or ROV-based), the beam angle of the system itself, the survey speed, and the distance to the seafloor. Significant advances in system accuracy, processing power and new software make multibeam mapping a powerful tool for studying sediment dynamics in 4D through repeated surveys that are ideally linked to additional studies on currents and sediment load in the water column. The Texelstroom channel, which is part of the Marsdiep between the city of Den Helder and the island of Texel (North Holland, the Netherlands), has been investigated in such a way for many years using water depth estimates from an ADCP installed on a ferry shuttling 24 times a day between the mainland and the island. Since 2009, repeated multibeam surveys have been undertaken up to three times per year as part of a student course, revealing sediment dynamics in much more detail than could be previously seen with the water depth estimates from the ferry-based ADCP. In the Texelstroom channel, the water depth ranges from a few meters to 45 meters. In the highly variable bathymetry, a series of large, bended sand waves exist mainly perpendicular to the direction of the main current. The shape of the sand waves changes from asymmetrical to symmetrical depending on the time of year, with more symmetrical shapes in spring and summer. Perpendicular to the large sand waves, smaller ripples develop during autumn. In addition to these changes in sand wave characteristics, sand wave crests sometimes migrate more than 30m in two months with an average movement of half a meter per day. The migration direction changes during the year resulting in a non-constant back-and-forth movement of the large sand waves. These intra-annual variations are characterized by changes in the slope of the sand waves, variations in the

  17. CASMI—A visualization tool for the World Stress Map database

    Science.gov (United States)

    Heidbach, Oliver; Höhne, Jens

    2008-07-01

    The World Stress Map (WSM) project has compiled a global database of quality-ranked data records on the contemporary tectonic stresses in the Earth's crust. The WSM 2005 database release contains approximately 16 000 data records from different types of stress indicators such as earthquake focal mechanisms solutions, well bore breakouts, hydraulic fracturing and overcoring measurements, as well as quaternary fault-slip data and volcanic alignments. To provide a software tool for database visualization, analysis and interpretation of stress data as well its integration with other data records, we developed the program CASMI. This public domain software tool for Unix-like operating systems enables the selection of stress data records from the WSM database according to location, data quality, type of stress indicator, and depth. Each selected data record is visualized by a symbol that represents the type of stress indicator and the orientation of the maximum horizontal compressive stress. Symbol size is proportional to the quality of the data record, and the colour indicates different tectonic regimes. Stress maps can be produced in different geographical projections and high-quality output formats. CASMI also allows the integration of user-defined stress data sets and a wide range of other data such as topography, Harvard centroid moment tensors, polygons, text data, and plate motion trajectories. CASMI, including the WSM 2005 database release, can be requested free of charge from the project's website at http://www.world-stress-map.org/casmi. We present two stress map examples generated with CASMI ranging from plate-wide to regional scale: (1) A stress map of central Europe, that reveals the correlation of stress field orientation and relative plate motion. (2) The fan-shape stress pattern in North Germany.

  18. Mapping a Difference: The Power of Geospatial Visualization

    Science.gov (United States)

    Kolvoord, B.

    2015-12-01

    Geospatial Technologies (GST), such as GIS, GPS and remote sensing, offer students and teachers the opportunity to study the "why" of where. By making maps and collecting location-based data, students can pursue authentic problems using sophisticated tools. The proliferation of web- and cloud-based tools has made these technologies broadly accessible to schools. In addition, strong spatial thinking skills have been shown to be a key factor in supporting students that want to study science, technology, engineering, and mathematics (STEM) disciplines (Wai, Lubinski and Benbow) and pursue STEM careers. Geospatial technologies strongly scaffold the development of these spatial thinking skills. For the last ten years, the Geospatial Semester, a unique dual-enrollment partnership between James Madison University and Virginia high schools, has provided students with the opportunity to use GST's to hone their spatial thinking skills and to do extended projects of local interest, including environmental, geological and ecological studies. Along with strong spatial thinking skills, these students have also shown strong problem solving skills, often beyond those of fellow students in AP classes. Programs like the Geospatial Semester are scalable and within the reach of many college and university departments, allowing strong engagement with K-12 schools. In this presentation, we'll share details of the Geospatial Semester and research results on the impact of the use of these technologies on students' spatial thinking skills, and discuss the success and challenges of developing K-12 partnerships centered on geospatial visualization.

  19. Probabilistic Mapping of Human Visual Attention from Head Pose Estimation

    Directory of Open Access Journals (Sweden)

    Andrea Veronese

    2017-10-01

    Full Text Available Effective interaction between a human and a robot requires the bidirectional perception and interpretation of actions and behavior. While actions can be identified as a directly observable activity, this might not be sufficient to deduce actions in a scene. For example, orienting our face toward a book might suggest the action toward “reading.” For a human observer, this deduction requires the direction of gaze, the object identified as a book and the intersection between gaze and book. With this in mind, we aim to estimate and map human visual attention as directed to a scene, and assess how this relates to the detection of objects and their related actions. In particular, we consider human head pose as measurement to infer the attention of a human engaged in a task and study which prior knowledge should be included in such a detection system. In a user study, we show the successful detection of attention to objects in a typical office task scenario (i.e., reading, working with a computer, studying an object. Our system requires a single external RGB camera for head pose measurements and a pre-recorded 3D point cloud of the environment.

  20. A Visual Interface Diagram For Mapping Functions In Integrated Products

    DEFF Research Database (Denmark)

    Ingerslev, Mattias; Oliver Jespersen, Mikkel; Göhler, Simon Moritz

    2015-01-01

    In product development there is a recognized tendency towards increased functionality for each new product generation. This leads to more integrated and complex products, with the risk of development delays and quality issues as a consequence of lacking overview and transparency. The work described...... in this article has been conducted in collaboration with Novo Nordisk on the insulin injection device FlexTouch® as case product. The FlexTouch® reflects the characteristics of an integrated product with several functions shared between a relatively low number of parts. In this article we present a novel way...... of visualizing relations between parts and functions in highly integrated mechanical products. The result is an interface diagram that supports design teams in communication, decision making and design management. The diagram gives the designer an overview of the couplings and dependencies within a product...

  1. Visual map and instruction-based bicycle navigation: a comparison of effects on behaviour

    NARCIS (Netherlands)

    de Waard, Dick; Westerhuis, Frank; Joling, Danielle; Weiland, Stella; Stadtbäumer, Ronja; Kaltofen, Leonie

    2017-01-01

    Cycling with a classic paper map was compared with navigating with a moving map displayed on a smartphone, and with auditory, and visual turn-by-turn route guidance. Spatial skills were found to be related to navigation performance, however only when navigating from a paper or electronic map, not

  2. Origin of the Dutch coastal landscape. Long-term landscape evolution of the Netherlands during the Holocene, described and visualized in national, regional and local palaeogeographical map series

    NARCIS (Netherlands)

    Vos, P.C.

    2015-01-01

    The topic of this thesis is the Origin of the Dutch coastal landscapes during the Holocene. The landscape evolution is visualized in a series of palaeogeographical maps, and the driving mechanisms behind the environmental changes are discussed. The practice to make palaeogeographical map

  3. Mapping scientific frontiers the quest for knowledge visualization

    CERN Document Server

    Chen, Chaomei

    2013-01-01

    In its revised edition, this book examines the history and current developments in knowledge visualization from an interdisciplinary perspective, from theories of invisible colleges and competing paradigms to practical applications of visualization techniques.

  4. Verbal vs. visual coding in modified mental imagery map exploration task

    Directory of Open Access Journals (Sweden)

    Ćirović Ivana

    2011-01-01

    Full Text Available We modified classical mental exploration task introducing verbal modality. Consequently, we could test robust effects from lexical processing in an attempt to understand whether the underlying mental representation is strictly propositional. In our three experiments, in addition to map modality (visual or verbal, lexical frequency, concreteness and visual frequency were also varied. The symbolic distance effect was replicated, regardless of map modality. Exploration of distances was regularly faster on pictorial maps. Effects of lexical frequency and concreteness were not significant for verbal maps. However, when visual frequency was introduced on pictorial maps both type of frequencies generated measurable effects. Our findings directly contradict the assumptions of propositional theories (1 subjects were faster in the visual modality, which would be difficult to explain if the perceptual code had to be transformed into propositional, (2 word frequency and concreteness did not contribute as would be expected if propositional code were a default.

  5. Mapping innovation processes: Visual techniques for opening and presenting the black box of service innovation processes

    DEFF Research Database (Denmark)

    Olesen, Anne Rørbæk

    2017-01-01

    This chapter argues for the usefulness of visual mapping techniques for performing qualitative analysis of complex service innovation processes. Different mapping formats are presented, namely, matrices, networks, process maps, situational analysis maps and temporal situational analysis maps....... For the purpose of researching service innovation processes, the three latter formats are argued to be particularly interesting. Process maps can give an overview of different periods and milestones in a process in one carefully organized location. Situational analysis maps and temporal situational analysis maps...... can open up complexities of service innovation processes, as well as close them down for presentational purposes. The mapping formats presented are illustrated by displaying maps from an exemplary research project, and the chapter is concluded with a brief discussion of the limitations and pitfalls...

  6. From digital mapping to GIS-based 3D visualization of geological maps: example from the Western Alps geological units

    Science.gov (United States)

    Balestro, Gianni; Cassulo, Roberto; Festa, Andrea; Fioraso, Gianfranco; Nicolò, Gabriele; Perotti, Luigi

    2015-04-01

    Collection of field geological data and sharing of geological maps are nowadays greatly enhanced by using digital tools and IT (Information Technology) applications. Portable hardware allows accurate GPS localization of data and homogeneous storing of information in field databases, whereas GIS (Geographic Information Systems) applications enable generalization of field data and realization of geological map databases. A further step in the digital processing of geological map information consists of building virtual visualization by means of GIS-based 3D viewers, that allow projection and draping of significant geological features over photo-realistic terrain models. Digital fieldwork activities carried out by the Authors in the Western Alps, together with building of geological map databases and related 3D visualizations, are an example of application of the above described digital technologies. Digital geological mapping was performed by means of a GIS mobile software loaded on a rugged handheld device, and lithological, structural and geomorphological features with their attributes were stored in different layers that form the field database. The latter was then generalized through usual map processing steps such as outcrops interpolation, characterization of geological boundaries and selection of meaningful punctual observations. This map databases was used for building virtual visualizations through a GIS-based 3D-viewer that loaded detailed DTM (resolution of 5 meters) and aerial images. 3D visualizations were focused on projection and draping of significant stratigraphic contacts (e.g. contacts that separate different Quaternary deposits) and tectonic contacts (i.e. exhumation-related contacts that dismembered original ophiolite sequences). In our experience digital geological mapping and related databases ensured homogeneous data storing and effective sharing of information, and allowed subsequent building of 3D GIS-based visualizations. The latters gave

  7. YouGenMap: a web platform for dynamic multi-comparative mapping and visualization of genetic maps

    Science.gov (United States)

    Keith Batesole; Kokulapalan Wimalanathan; Lin Liu; Fan Zhang; Craig S. Echt; Chun Liang

    2014-01-01

    Comparative genetic maps are used in examination of genome organization, detection of conserved gene order, and exploration of marker order variations. YouGenMap is an open-source web tool that offers dynamic comparative mapping capability of users' own genetic mapping between 2 or more map sets. Users' genetic map data and optional gene annotations are...

  8. Visualizing the semantic content of large text databases using text maps

    Science.gov (United States)

    Combs, Nathan

    1993-01-01

    A methodology for generating text map representations of the semantic content of text databases is presented. Text maps provide a graphical metaphor for conceptualizing and visualizing the contents and data interrelationships of large text databases. Described are a set of experiments conducted against the TIPSTER corpora of Wall Street Journal articles. These experiments provide an introduction to current work in the representation and visualization of documents by way of their semantic content.

  9. Areas activated during naturalistic reading comprehension overlap topological visual, auditory, and somatotomotor maps.

    Science.gov (United States)

    Sood, Mariam R; Sereno, Martin I

    2016-08-01

    Cortical mapping techniques using fMRI have been instrumental in identifying the boundaries of topological (neighbor-preserving) maps in early sensory areas. The presence of topological maps beyond early sensory areas raises the possibility that they might play a significant role in other cognitive systems, and that topological mapping might help to delineate areas involved in higher cognitive processes. In this study, we combine surface-based visual, auditory, and somatomotor mapping methods with a naturalistic reading comprehension task in the same group of subjects to provide a qualitative and quantitative assessment of the cortical overlap between sensory-motor maps in all major sensory modalities, and reading processing regions. Our results suggest that cortical activation during naturalistic reading comprehension overlaps more extensively with topological sensory-motor maps than has been heretofore appreciated. Reading activation in regions adjacent to occipital lobe and inferior parietal lobe almost completely overlaps visual maps, whereas a significant portion of frontal activation for reading in dorsolateral and ventral prefrontal cortex overlaps both visual and auditory maps. Even classical language regions in superior temporal cortex are partially overlapped by topological visual and auditory maps. By contrast, the main overlap with somatomotor maps is restricted to a small region on the anterior bank of the central sulcus near the border between the face and hand representations of M-I. Hum Brain Mapp 37:2784-2810, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  10. TRAFFIC SIGN DETECTION BASED ON BIOLOGICALLY VISUAL MECHANISM

    Directory of Open Access Journals (Sweden)

    X. Hu

    2012-07-01

    Full Text Available TSR (Traffic sign recognition is an important problem in ITS (intelligent traffic system, which is being paid more and more attention for realizing drivers assisting system and unmanned vehicle etc. TSR consists of two steps: detection and recognition, and this paper describe a new traffic sign detection method. The design principle of the traffic sign is comply with the visual attention mechanism of human, so we propose a method using visual attention mechanism to detect traffic sign ,which is reasonable. In our method, the whole scene will firstly be analyzed by visual attention model to acquire the area where traffic signs might be placed. And then, these candidate areas will be analyzed according to the shape characteristics of the traffic sign to detect traffic signs. In traffic sign detection experiments, the result shows the proposed method is effectively and robust than other existing saliency detection method.

  11. Constellation Map: Downstream visualization and interpretation of gene set enrichment results.

    Science.gov (United States)

    Tan, Yan; Wu, Felix; Tamayo, Pablo; Haining, W Nicholas; Mesirov, Jill P

    2015-01-01

    Gene set enrichment analysis (GSEA) approaches are widely used to identify coordinately regulated genes associated with phenotypes of interest. Here, we present Constellation Map, a tool to visualize and interpret the results when enrichment analyses yield a long list of significantly enriched gene sets. Constellation Map identifies commonalities that explain the enrichment of multiple top-scoring gene sets and maps the relationships between them. Constellation Map can help investigators take full advantage of GSEA and facilitates the biological interpretation of enrichment results. Constellation Map is freely available as a GenePattern module at http://www.genepattern.org.

  12. Attention Priority Map of Face Images in Human Early Visual Cortex.

    Science.gov (United States)

    Mo, Ce; He, Dongjun; Fang, Fang

    2018-01-03

    Attention priority maps are topographic representations that are used for attention selection and guidance of task-related behavior during visual processing. Previous studies have identified attention priority maps of simple artificial stimuli in multiple cortical and subcortical areas, but investigating neural correlates of priority maps of natural stimuli is complicated by the complexity of their spatial structure and the difficulty of behaviorally characterizing their priority map. To overcome these challenges, we reconstructed the topographic representations of upright/inverted face images from fMRI BOLD signals in human early visual areas primary visual cortex (V1) and the extrastriate cortex (V2 and V3) based on a voxelwise population receptive field model. We characterized the priority map behaviorally as the first saccadic eye movement pattern when subjects performed a face-matching task relative to the condition in which subjects performed a phase-scrambled face-matching task. We found that the differential first saccadic eye movement pattern between upright/inverted and scrambled faces could be predicted from the reconstructed topographic representations in V1-V3 in humans of either sex. The coupling between the reconstructed representation and the eye movement pattern increased from V1 to V2/3 for the upright faces, whereas no such effect was found for the inverted faces. Moreover, face inversion modulated the coupling in V2/3, but not in V1. Our findings provide new evidence for priority maps of natural stimuli in early visual areas and extend traditional attention priority map theories by revealing another critical factor that affects priority maps in extrastriate cortex in addition to physical salience and task goal relevance: image configuration. SIGNIFICANCE STATEMENT Prominent theories of attention posit that attention sampling of visual information is mediated by a series of interacting topographic representations of visual space known as

  13. Adaptive visual and auditory map alignment in barn owl superior colliculus and its neuromorphic implementation.

    Science.gov (United States)

    Huo, Juan; Murray, Alan; Wei, Dongqing

    2012-09-01

    Adaptation is one of the most important phenomena in biology. A young barn owl can adapt to imposed environmental changes, such as artificial visual distortion caused by wearing a prism. This adjustment process has been modeled mathematically and the model replicates the sensory map realignment of barn owl superior colliculus (SC) through axonogenesis and synaptogenesis. This allows the biological mechanism to be transferred to an artificial computing system and thereby imbue it with a new form of adaptability to the environment. The model is demonstrated in a real-time robot environment. Results of the experiments are compared with and without prism distortion of vision, and show improved adaptability for the robot. However, the computation speed of the embedded system in the robot is slow. A digital and analog mixed signal very-large-scale integration (VLSI) circuit has been fabricated to implement adaptive sensory pathway changes derived from the SC model at higher speed. VLSI experimental results are consistent with simulation results.

  14. A Visual Framework for Digital Reconstruction of Topographic Maps

    KAUST Repository

    Thabet, Ali Kassem

    2014-09-30

    We present a framework for reconstructing Digital Elevation Maps (DEM) from scanned topographic maps. We first rectify the images to ensure that maps fit together without distortion. To segment iso-contours, we have developed a novel semi-automated method based on mean-shifts that requires only minimal user interaction. Contour labels are automatically read using an OCR module. To reconstruct the output DEM from scattered data, we generalize natural neighbor interpolation to handle the transfinite case (contours and points). To this end, we use parallel vector propagation to compute a discrete Voronoi diagram of the constraints, and a modified floodfill to compute virtual Voronoi tiles. Our framework is able to handle tens of thousands of contours and points and can generate DEMs comprising more than 100 million samples. We provide quantitative comparison to commercial software and show the benefits of our approach. We furthermore show the robustness of our method on a massive set of old maps predating satellite acquisition. Compared to other methods, our framework is able to accurately and efficiently generate a final DEM despite inconsistencies, sparse or missing contours even for highly complex and cluttered maps. Therefore, this method has broad applicability for digitization and reconstruction of the world\\'s old topographic maps that are often the only record of past landscapess and cultural heritage before their destruction under modern development.

  15. Distinctive neural mechanisms supporting visual object individuation and identification.

    Science.gov (United States)

    Xu, Yaoda

    2009-03-01

    Many everyday activities, such as driving on a busy street, require the encoding of distinctive visual objects from crowded scenes. Given resource limitations of our visual system, one solution to this difficult and challenging task is to first select individual objects from a crowded scene (object individuation) and then encode their details (object identification). Using functional magnetic resonance imaging, two distinctive brain mechanisms were recently identified that support these two stages of visual object processing. While the inferior intraparietal sulcus (IPS) selects a fixed number of about four objects via their spatial locations, the superior IPS and the lateral occipital complex (LOC) encode the features of a subset of the selected objects in great detail (object shapes in this case). Thus, the inferior IPS individuates visual objects from a crowded display and the superior IPS and higher visual areas participate in subsequent object identification. Consistent with the prediction of this theory, even when only object shape identity but not its location is task relevant, this study shows that object individuation in the inferior IPS treats four identical objects similarly as four objects that are all different, whereas object shape identification in the superior IPS and the LOC treat four identical objects as a single unique object. These results provide independent confirmation supporting the dissociation between visual object individuation and identification in the brain.

  16. Functional MRI mapping of visual function and selective attention for performance assessment and presurgical planning using conjunctive visual search.

    Science.gov (United States)

    Parker, Jason G; Zalusky, Eric J; Kirbas, Cemil

    2014-03-01

    Accurate mapping of visual function and selective attention using fMRI is important in the study of human performance as well as in presurgical treatment planning of lesions in or near visual centers of the brain. Conjunctive visual search (CVS) is a useful tool for mapping visual function during fMRI because of its greater activation extent compared with high-capacity parallel search processes. The purpose of this work was to develop and evaluate a CVS that was capable of generating consistent activation in the basic and higher level visual areas of the brain by using a high number of distractors as well as an optimized contrast condition. Images from 10 healthy volunteers were analyzed and brain regions of greatest activation and deactivation were determined using a nonbiased decomposition of the results at the hemisphere, lobe, and gyrus levels. The results were quantified in terms of activation and deactivation extent and mean z-statistic. The proposed CVS was found to generate robust activation of the occipital lobe, as well as regions in the middle frontal gyrus associated with coordinating eye movements and in regions of the insula associated with task-level control and focal attention. As expected, the task demonstrated deactivation patterns commonly implicated in the default-mode network. Further deactivation was noted in the posterior region of the cerebellum, most likely associated with the formation of optimal search strategy. We believe the task will be useful in studies of visual and selective attention in the neuroscience community as well as in mapping visual function in clinical fMRI.

  17. Visual cortex in aging and Alzheimer’s disease: Changes in visual field maps and population receptive fields

    Directory of Open Access Journals (Sweden)

    Alyssa A. Brewer

    2014-02-01

    Full Text Available Although several studies have suggested that cortical alterations underlie such age-related visual deficits as decreased acuity, little is known about what changes actually occur in visual cortex during healthy aging. Two recent studies showed changes in primary visual cortex (V1 during normal aging; however, no studies have characterized the effects of aging on visual cortex beyond V1, important measurements both for understanding the aging process and for comparison to changes in age-related diseases. Similarly, there is almost no information about changes in visual cortex in Alzheimer’s disease (AD, the most common form of dementia. Because visual deficits are often reported as one of the first symptoms of AD, measurements of such changes in the visual cortex of AD patients might improve our understanding of how the visual system is affected by neurodegeneration as well as aid early detection, accurate diagnosis and timely treatment of AD. Here we use fMRI to first compare the visual field map (VFM organization and population receptive fields (pRFs between young adults and healthy aging subjects for occipital VFMs V1, V2, V3, and hV4. Healthy aging subjects do not show major VFM organizational deficits, but do have reduced surface area and increased pRF sizes in the foveal representations of V1, V2, and hV4 relative to healthy young control subjects. These measurements are consistent with behavioral deficits seen in healthy aging. We then demonstrate the feasibility and first characterization of these measurements in two patients with mild AD, which reveal potential changes in visual cortex as part of the pathophysiology of AD. Our data aid in our understanding of the changes in the visual processing pathways in normal aging and provide the foundation for future research into earlier and more definitive detection of AD.

  18. Retinotopic mapping of the human visual cortex at a magnetic field strength of 7T.

    Science.gov (United States)

    Hoffmann, Michael B; Stadler, Jörg; Kanowski, Martin; Speck, Oliver

    2009-01-01

    fMRI-based retinotopic mapping data obtained at a magnetic field strength of 7T are evaluated and compared to 3T acquisitions. With established techniques retinotopic mapping data were obtained in four subjects for 25 slices parallel to the calcarine sulcus at 7 and 3T for three voxel sizes (2.5(3), 1.4(3), and 1.1(3)mm(3)) and in two subjects for 49 slices at 7T for 2.5(3)mm(3) voxels. The data were projected to the flattened representation of T1 weighted images acquired at 3T. The obtained retinotopic maps allowed for the identification of visual areas in the occipito-parietal cortex. The mean coherence increased with magnetic field strength and with voxel size. At 7T, the occipital cortex could be sampled with high sensitivity in a short single session at high resolution. Alternatively, at lower resolution simultaneous mapping of a great expanse of occipito-parietal cortex was possible. Retinotopic mapping at 7T aids a detailed description of the visual areas. Here, recent findings of multiple stimulus-driven retinotopic maps along the intraparietal sulcus are supported. Retinotopic mapping at 7T opens the possibility to detail our understanding of the cortical visual field representations in general and of their plasticity in visual system pathologies.

  19. Genome contact map explorer: a platform for the comparison, interactive visualization and analysis of genome contact maps

    Science.gov (United States)

    Kumar, Rajendra; Sobhy, Haitham

    2017-01-01

    Abstract Hi-C experiments generate data in form of large genome contact maps (Hi-C maps). These show that chromosomes are arranged in a hierarchy of three-dimensional compartments. But to understand how these compartments form and by how much they affect genetic processes such as gene regulation, biologists and bioinformaticians need efficient tools to visualize and analyze Hi-C data. However, this is technically challenging because these maps are big. In this paper, we remedied this problem, partly by implementing an efficient file format and developed the genome contact map explorer platform. Apart from tools to process Hi-C data, such as normalization methods and a programmable interface, we made a graphical interface that let users browse, scroll and zoom Hi-C maps to visually search for patterns in the Hi-C data. In the software, it is also possible to browse several maps simultaneously and plot related genomic data. The software is openly accessible to the scientific community. PMID:28973466

  20. Two distinct neural mechanisms in early visual cortex determine subsequent visual processing.

    Science.gov (United States)

    Jacobs, Christianne; de Graaf, Tom A; Sack, Alexander T

    2014-10-01

    Neuroscience research has conventionally focused on how the brain processes sensory information, after the information has been received. Recently, increased interest focuses on how the state of the brain upon receiving inputs determines and biases their subsequent processing and interpretation. Here, we investigated such 'pre-stimulus' brain mechanisms and their relevance for objective and subjective visual processing. Using non-invasive focal brain stimulation [transcranial magnetic stimulation (TMS)] we disrupted spontaneous brain state activity within early visual cortex (EVC) before onset of visual stimulation, at two different pre-stimulus-onset-asynchronies (pSOAs). We found that TMS pulses applied to EVC at either 20 msec or 50 msec before onset of a simple orientation stimulus both prevented this stimulus from reaching visual awareness. Interestingly, only the TMS-induced visual suppression following TMS at a pSOA of ?20 msec was retinotopically specific, while TMS at a pSOA of ?50 msec was not. In a second experiment, we used more complex symbolic arrow stimuli, and found TMS-induced suppression only when disrupting EVC at a pSOA of ? ?60 msec, which, in line with Experiment 1, was not retinotopically specific. Despite this topographic unspecificity of the ?50 msec effect, the additional control measurements as well as tracking and removal of eye blinks, suggested that also this effect was not the result of an unspecific artifact, and thus neural in origin. We therefore obtained evidence of two distinct neural mechanisms taking place in EVC, both determining whether or not subsequent visual inputs are successfully processed by the human visual system.

  1. Visualizing Proportions and Dissimilarities by Space-filling Maps

    DEFF Research Database (Denmark)

    Carrizosa, Emilio; Guerrero, Vanesa; Morales, Dolores Romero

    2017-01-01

    In this paper we address the problem of visualizing a set of individuals, which have attached a statistical value given as a proportion, and a dissimilarity measure. Each individual is represented as a region within the unit square, in such a way that the area of the regions represent the proport...

  2. Wearable Gaze Trackers: Mapping Visual Attention in 3D

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Stets, Jonathan Dyssel; Suurmets, Seidi

    2017-01-01

    The study of visual attention in humans relates to a wide range of areas such as: psychology, cognition, usability, and marketing. These studies have been limited to fixed setups with respondents sitting in front of a monitor mounted with a gaze tracking device. The introduction of wearable mobile...

  3. Algebra of the Visual: The London Underground Map and the Art It Has Inspired

    Directory of Open Access Journals (Sweden)

    Alan Ashton-Smith

    2011-01-01

    Full Text Available "Algebra of the Visual: The London Underground Map and the Art It Has Inspired" by Alan Ashton-Smith. The London Underground symbolizes London, and the London Underground map, designed by Harry Beck in 1931, symbolizes the London Underground. Accordingly, Beck’s map has in itself come to be a recognizable signifier of London. Its impact resonates beyond this city though: it is also the prototype for metro maps worldwide, with its basic topological structure having been adopted for use on the subways of many other cities. (NANO: New American Notes Online

  4. Visual map and instruction-based bicycle navigation: a comparison of effects on behaviour.

    Science.gov (United States)

    de Waard, Dick; Westerhuis, Frank; Joling, Danielle; Weiland, Stella; Stadtbäumer, Ronja; Kaltofen, Leonie

    2017-09-01

    Cycling with a classic paper map was compared with navigating with a moving map displayed on a smartphone, and with auditory, and visual turn-by-turn route guidance. Spatial skills were found to be related to navigation performance, however only when navigating from a paper or electronic map, not with turn-by-turn (instruction based) navigation. While navigating, 25% of the time cyclists fixated at the devices that present visual information. Navigating from a paper map required most mental effort and both young and older cyclists preferred electronic over paper map navigation. In particular a turn-by-turn dedicated guidance device was favoured. Visual maps are in particular useful for cyclists with higher spatial skills. Turn-by-turn information is used by all cyclists, and it is useful to make these directions available in all devices. Practitioner Summary: Electronic navigation devices are preferred over a paper map. People with lower spatial skills benefit most from turn-by-turn guidance information, presented either auditory or on a dedicated device. People with higher spatial skills perform well with all devices. It is advised to keep in mind that all users benefit from turn-by-turn information when developing a navigation device for cyclists.

  5. Fracture mechanisms in biopolymer films using coupling of mechanical analysis and high speed visualization technique

    NARCIS (Netherlands)

    Paes, S.S.; Yakimets, I.; Wellner, N.; Hill, S.E.; Wilson, R.H.; Mitchell, J.R.

    2010-01-01

    The aim of this study was to provide a detailed description of the fracture mechanisms in three different biopolymer thin materials: gelatin, hydroxypropyl cellulose (HPC) and cassava starch films. That was achieved by using a combination of fracture mechanics methodology and in situ visualization

  6. Visualizing Article Similarities via Sparsified Article Network and Map Projection for Systematic Reviews.

    Science.gov (United States)

    Ji, Xiaonan; Machiraju, Raghu; Ritter, Alan; Yen, Po-Yin

    2017-01-01

    Systematic Reviews (SRs) of biomedical literature summarize evidence from high-quality studies to inform clinical decisions, but are time and labor intensive due to the large number of article collections. Article similarities established from textual features have been shown to assist in the identification of relevant articles, thus facilitating the article screening process efficiently. In this study, we visualized article similarities to extend its utilization in practical settings for SR researchers, aiming to promote human comprehension of article distributions and hidden patterns. To prompt an effective visualization in an interpretable, intuitive, and scalable way, we implemented a graph-based network visualization with three network sparsification approaches and a distance-based map projection via dimensionality reduction. We evaluated and compared three network sparsification approaches and the visualization types (article network vs. article map). We demonstrated the effectiveness in revealing article distribution and exhibiting clustering patterns of relevant articles with practical meanings for SRs.

  7. Visualizing the Quality of Vectur Features - a Proposal for Cadastral Maps

    Science.gov (United States)

    Navratil, G.; Leopoldseder, V.

    2017-09-01

    A well-known problem of geographical information is the communication of the quality level. It can be either done verbally / numerically or it can be done graphically. The graphical form is especially useful if the quality has a spatial variation because the spatial distribution is visualized as well. The problem of spatial variation of quality is an issue for cadastral maps. Non-experts cannot determine the quality at a specific location. Therefore a visual representation was tested for the Austrian cadastre. A map sheet was redesigned to give some indication of cadastral quality and presented to both experts and non-experts. The paper presents the result of the interviews.

  8. Self-Organizing Hidden Markov Model Map (SOHMMM): Biological Sequence Clustering and Cluster Visualization.

    Science.gov (United States)

    Ferles, Christos; Beaufort, William-Scott; Ferle, Vanessa

    2017-01-01

    The present study devises mapping methodologies and projection techniques that visualize and demonstrate biological sequence data clustering results. The Sequence Data Density Display (SDDD) and Sequence Likelihood Projection (SLP) visualizations represent the input symbolical sequences in a lower-dimensional space in such a way that the clusters and relations of data elements are depicted graphically. Both operate in combination/synergy with the Self-Organizing Hidden Markov Model Map (SOHMMM). The resulting unified framework is in position to analyze automatically and directly raw sequence data. This analysis is carried out with little, or even complete absence of, prior information/domain knowledge.

  9. Visualization of Nonlinear Classification Models in Neuroimaging - Signed Sensitivity Maps

    DEFF Research Database (Denmark)

    Rasmussen, Peter Mondrup; Schmah, Tanya; Madsen, Kristoffer Hougaard

    2012-01-01

    Classification models are becoming increasing popular tools in the analysis of neuroimaging data sets. Besides obtaining good prediction accuracy, a competing goal is to interpret how the classifier works. From a neuroscientific perspective, we are interested in the brain pattern reflecting...... the underlying neural encoding of an experiment defining multiple brain states. In this relation there is a great desire for the researcher to generate brain maps, that highlight brain locations of importance to the classifiers decisions. Based on sensitivity analysis, we develop further procedures for model...

  10. Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

    KAUST Repository

    Bhatia, H.

    2012-09-01

    Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures. © 2012 IEEE.

  11. Will it Blend? Visualization and Accuracy Evaluation of High-Resolution Fuzzy Vegetation Maps

    Science.gov (United States)

    Zlinszky, A.; Kania, A.

    2016-06-01

    Instead of assigning every map pixel to a single class, fuzzy classification includes information on the class assigned to each pixel but also the certainty of this class and the alternative possible classes based on fuzzy set theory. The advantages of fuzzy classification for vegetation mapping are well recognized, but the accuracy and uncertainty of fuzzy maps cannot be directly quantified with indices developed for hard-boundary categorizations. The rich information in such a map is impossible to convey with a single map product or accuracy figure. Here we introduce a suite of evaluation indices and visualization products for fuzzy maps generated with ensemble classifiers. We also propose a way of evaluating classwise prediction certainty with "dominance profiles" visualizing the number of pixels in bins according to the probability of the dominant class, also showing the probability of all the other classes. Together, these data products allow a quantitative understanding of the rich information in a fuzzy raster map both for individual classes and in terms of variability in space, and also establish the connection between spatially explicit class certainty and traditional accuracy metrics. These map products are directly comparable to widely used hard boundary evaluation procedures, support active learning-based iterative classification and can be applied for operational use.

  12. Probability Maps for the Visualization of Assimilation Ensemble Flow Data

    KAUST Repository

    Hollt, Thomas

    2015-05-25

    Ocean forecasts nowadays are created by running ensemble simulations in combination with data assimilation techniques. Most of these techniques resample the ensemble members after each assimilation cycle. This means that in a time series, after resampling, every member can follow up on any of the members before resampling. Tracking behavior over time, such as all possible paths of a particle in an ensemble vector field, becomes very difficult, as the number of combinations rises exponentially with the number of assimilation cycles. In general a single possible path is not of interest but only the probabilities that any point in space might be reached by a particle at some point in time. In this work we present an approach using probability-weighted piecewise particle trajectories to allow such a mapping interactively, instead of tracing quadrillions of individual particles. We achieve interactive rates by binning the domain and splitting up the tracing process into the individual assimilation cycles, so that particles that fall into the same bin after a cycle can be treated as a single particle with a larger probability as input for the next time step. As a result we loose the possibility to track individual particles, but can create probability maps for any desired seed at interactive rates.

  13. VISUAL UAV TRAJECTORY PLAN SYSTEM BASED ON NETWORK MAP

    Directory of Open Access Journals (Sweden)

    X. L. Li

    2012-07-01

    Full Text Available The base map of the current software UP-30 using in trajectory plan for Unmanned Aircraft Vehicle is vector diagram. UP-30 draws navigation points manually. But in the field of operation process, the efficiency and the quality of work is influenced because of insufficient information, screen reflection, calculate inconveniently and other factors. If we do this work in indoor, the effect of external factors on the results would be eliminated, the network earth users can browse the free world high definition satellite images through downloading a client software, and can export the high resolution image by standard file format. This brings unprecedented convenient of trajectory plan. But the images must be disposed by coordinate transformation, geometric correction. In addition, according to the requirement of mapping scale ,camera parameters and overlap degree we can calculate exposure hole interval and trajectory distance between the adjacent trajectory automatically . This will improve the degree of automation of data collection. Software will judge the position of next point according to the intersection of the trajectory and the survey area and ensure the position of point according to trajectory distance. We can undertake the points artificially. So the trajectory plan is automatic and flexible. Considering safety, the date can be used in flying after simulating flight. Finally we can export all of the date using a key

  14. The integrity of visual-proprioceptive mapping in cerebral palsy.

    Science.gov (United States)

    Wann, J P

    1991-01-01

    Existing data on the ability of normal children to make intra-modal and cross-modal judgements about limb position are reviewed. A pattern of results emerges which suggests that although young children have difficulty with proprioceptive judgements, their performance is significantly enhanced if the task involves matching vision against proprioception. Some preliminary findings with cerebral palsied children suggest that this advantage may sometimes be lost. It is suggested, however, that the tasks used in previous studies do not allow the precise appraisal of this ability. This study examined intra- and cross-modal judgements in eight normal adults and eight severely cerebral palsied adolescents. In addition to the usual measures of spatial accuracy, joint angle measurements were recorded which allow some appraisal of the information strategy used for respective tasks. The results suggest that the cerebral palsied students had specific problems with mapping between vision and proprioception. This is discussed from a perspective of whether such mapping requires adaptive behaviour within a stable explorative environment, which is disrupted in cases of severe cerebral palsy.

  15. Daily Goals Formulation and Enhanced Visualization of Mechanical Ventilation Variance Improves Mechanical Ventilation Score.

    Science.gov (United States)

    Walsh, Brian K; Smallwood, Craig; Rettig, Jordan; Kacmarek, Robert M; Thompson, John; Arnold, John H

    2017-03-01

    The systematic implementation of evidence-based practice through the use of guidelines, checklists, and protocols mitigates the risks associated with mechanical ventilation, yet variation in practice remains prevalent. Recent advances in software and hardware have allowed for the development and deployment of an enhanced visualization tool that identifies mechanical ventilation goal variance. Our aim was to assess the utility of daily goal establishment and a computer-aided visualization of variance. This study was composed of 3 phases: a retrospective observational phase (baseline) followed by 2 prospective sequential interventions. Phase I intervention comprised daily goal establishment of mechanical ventilation. Phase II intervention was the setting and monitoring of daily goals of mechanical ventilation with a web-based data visualization system (T3). A single score of mechanical ventilation was developed to evaluate the outcome. The baseline phase evaluated 130 subjects, phase I enrolled 31 subjects, and phase II enrolled 36 subjects. There were no differences in demographic characteristics between cohorts. A total of 171 verbalizations of goals of mechanical ventilation were completed in phase I. The use of T3 increased by 87% from phase I. Mechanical ventilation score improved by 8.4% in phase I and 11.3% in phase II from baseline ( P = .032). The largest effect was in the low risk V T category, with a 40.3% improvement from baseline in phase I, which was maintained at 39% improvement from baseline in phase II ( P = .01). mechanical ventilation score was 9% higher on average in those who survived. Daily goal formation and computer-enhanced visualization of mechanical ventilation variance were associated with an improvement in goal attainment by evidence of an improved mechanical ventilation score. Further research is needed to determine whether improvements in mechanical ventilation score through a targeted, process-oriented intervention will lead to

  16. Maps of cone opsin input to mouse V1 and higher visual areas.

    Science.gov (United States)

    Rhim, Issac; Coello-Reyes, Gabriela; Ko, Hee-Kyoung; Nauhaus, Ian

    2017-04-01

    Studies in the mouse retina have characterized the spatial distribution of an anisotropic ganglion cell and photoreceptor mosaic, which provides a solid foundation to study how the cortex pools from afferent parallel color channels. In particular, the mouse's retinal mosaic exhibits a gradient of wavelength sensitivity along its dorsoventral axis. Cones at the ventral extreme mainly express S opsin, which is sensitive to ultraviolet (UV) wavelengths. Then, moving toward the retina's dorsal extreme, there is a transition to M-opsin dominance. Here, we tested the hypothesis that the retina's opsin gradient is recapitulated in cortical visual areas as a functional map of wavelength sensitivity. We first identified visual areas in each mouse by mapping retinotopy with intrinsic signal imaging (ISI). Next, we measured ISI responses to stimuli along different directions of the S- and M-color plane to quantify the magnitude of S and M input to each location of the retinotopic maps in five visual cortical areas (V1, AL, LM, PM, and RL). The results illustrate a significant change in the S:M-opsin input ratio along the axis of vertical retinotopy that is consistent with the gradient along the dorsoventral axis of the retina. In particular, V1 populations encoding the upper visual field responded to S-opsin contrast with 6.1-fold greater amplitude than to M-opsin contrast. V1 neurons encoding lower fields responded with 4.6-fold greater amplitude to M- than S-opsin contrast. The maps in V1 and higher visual areas (HVAs) underscore the significance of a wavelength sensitivity gradient for guiding the mouse's behavior.NEW & NOTEWORTHY Two elements of this study are particularly novel. For one, it is the first to quantify cone inputs to mouse visual cortex; we have measured cone input in five visual areas. Next, it is the first study to identify a feature map in the mouse visual cortex that is based on well-characterized anisotropy of cones in the retina; we have identified

  17. StreamMap: Smooth Dynamic Visualization of High-Density Streaming Points.

    Science.gov (United States)

    Li, Chenhui; Baciu, George; Yu, Han

    2017-02-13

    Interactive visualization of streaming points for real-time scatterplots and linear blending of correlation patterns is increasingly becoming the dominant mode of visual analytics for both big data and streaming data from active sensors and broadcasting media. To better visualize and interact with inter-stream patterns, it is generally necessary to smooth out gaps or distortions in the streaming data. Previous approaches either animate the points directly or present a sampled static heatmap. We propose a new approach, called StreamMap, to smoothly blend high-density streaming points and create a visual flow that emphasizes the density pattern distributions. In essence, we present three new contributions for the visualization of high-density streaming points. The first contribution is a density-based method called super kernel density estimation that aggregates streaming points using an adaptive kernel to solve the overlapping problem. The second contribution is a robust density morphing algorithm that generates several smooth intermediate frames for a given pair of frames. The third contribution is a trend representation design that can help convey the flow directions of the streaming points. The experimental results on three datasets demonstrate the effectiveness of StreamMap when dynamic visualization and visual analysis of trend patterns on streaming points are required.

  18. Visualizing the topical structure of the medical sciences: a self-organizing map approach.

    Science.gov (United States)

    Skupin, André; Biberstine, Joseph R; Börner, Katy

    2013-01-01

    We implement a high-resolution visualization of the medical knowledge domain using the self-organizing map (SOM) method, based on a corpus of over two million publications. While self-organizing maps have been used for document visualization for some time, (1) little is known about how to deal with truly large document collections in conjunction with a large number of SOM neurons, (2) post-training geometric and semiotic transformations of the SOM tend to be limited, and (3) no user studies have been conducted with domain experts to validate the utility and readability of the resulting visualizations. Our study makes key contributions to all of these issues. Documents extracted from Medline and Scopus are analyzed on the basis of indexer-assigned MeSH terms. Initial dimensionality is reduced to include only the top 10% most frequent terms and the resulting document vectors are then used to train a large SOM consisting of over 75,000 neurons. The resulting two-dimensional model of the high-dimensional input space is then transformed into a large-format map by using geographic information system (GIS) techniques and cartographic design principles. This map is then annotated and evaluated by ten experts stemming from the biomedical and other domains. Study results demonstrate that it is possible to transform a very large document corpus into a map that is visually engaging and conceptually stimulating to subject experts from both inside and outside of the particular knowledge domain. The challenges of dealing with a truly large corpus come to the fore and require embracing parallelization and use of supercomputing resources to solve otherwise intractable computational tasks. Among the envisaged future efforts are the creation of a highly interactive interface and the elaboration of the notion of this map of medicine acting as a base map, onto which other knowledge artifacts could be overlaid.

  19. Visualizing the topical structure of the medical sciences: a self-organizing map approach.

    Directory of Open Access Journals (Sweden)

    André Skupin

    Full Text Available We implement a high-resolution visualization of the medical knowledge domain using the self-organizing map (SOM method, based on a corpus of over two million publications. While self-organizing maps have been used for document visualization for some time, (1 little is known about how to deal with truly large document collections in conjunction with a large number of SOM neurons, (2 post-training geometric and semiotic transformations of the SOM tend to be limited, and (3 no user studies have been conducted with domain experts to validate the utility and readability of the resulting visualizations. Our study makes key contributions to all of these issues.Documents extracted from Medline and Scopus are analyzed on the basis of indexer-assigned MeSH terms. Initial dimensionality is reduced to include only the top 10% most frequent terms and the resulting document vectors are then used to train a large SOM consisting of over 75,000 neurons. The resulting two-dimensional model of the high-dimensional input space is then transformed into a large-format map by using geographic information system (GIS techniques and cartographic design principles. This map is then annotated and evaluated by ten experts stemming from the biomedical and other domains.Study results demonstrate that it is possible to transform a very large document corpus into a map that is visually engaging and conceptually stimulating to subject experts from both inside and outside of the particular knowledge domain. The challenges of dealing with a truly large corpus come to the fore and require embracing parallelization and use of supercomputing resources to solve otherwise intractable computational tasks. Among the envisaged future efforts are the creation of a highly interactive interface and the elaboration of the notion of this map of medicine acting as a base map, onto which other knowledge artifacts could be overlaid.

  20. Retinotopic Mapping of the Human Visual System with Magnetoencephalography.

    Science.gov (United States)

    1987-12-01

    optic fibers from the eye to the brain. Lettvin and Maturana along with other scientists cut optic fibers from the frog brain and watched them...Physics. 3rd ed. New York: John Wiley and Sons, 1966. 11. Liboff, R.L. Introductory Quantum Mechanics. Oakland CA: Holden Day inc., 1980. * 12. Maturana

  1. Map of Life: Measuring and Visualizing Species' Relatedness with "Molecular Distance Maps"

    OpenAIRE

    Kari, Lila; Hill, Kathleen A.; Sayem, Abu Sadat; Bryans, Nathaniel; Davis, Katelyn; Dattani, Nikesh S.

    2013-01-01

    We propose a novel combination of methods that (i) portrays quantitative characteristics of a DNA sequence as an image, (ii) computes distances between these images, and (iii) uses these distances to output a map wherein each sequence is a point in a common Euclidean space. In the resulting "Molecular Distance Map" each point signifies a DNA sequence, and the geometric distance between any two points reflects the degree of relatedness between the corresponding sequences and species. Molecular...

  2. Signaling of mechanical stretch in human keratinocytes via MAP kinases.

    Science.gov (United States)

    Kippenberger, S; Bernd, A; Loitsch, S; Guschel, M; Müller, J; Bereiter-Hahn, J; Kaufmann, R

    2000-03-01

    Cells within human skin are permanently exposed to mechanical stretching. Here we present evidence that alterations in cell shape trigger biochemical signaling via MAP kinases in human keratinocytes. In an in vitro attempt we demonstrate a fast but transient activation of extracellular signal-regulated kinases 1/2 in response to cell stretch. This activation is reversed by preincubation with functional blocking antibodies directed towards beta1-integrins. As a second member of MAP kinases, stress-activated protein kinase/c-JUN NH2-terminal kinase was activated in a slower fashion, peaking at 1 h after the initial stimulus. The delay in signal transmission suggests that extracellular signal-regulated kinases 1/2 and stress-activated protein kinase/c-JUN NH2-terminal kinase do not share the same signaling pathway. p38 was not activated by cell stretching. The contribution of cytoskeletal elements in signal perception and transduction was evaluated by selective disruption of either actin filaments, microtubules, or keratin filaments but showed no clear effect on stretch-induced activation of extracellular signal-regulated kinases 1/2 and stress-activated protein kinase/c-JUN NH2-terminal kinase. In conclusion we found evidence of a cell-shape-dependent activation of MAP kinases in human keratinocytes disclosing beta1-integrins as putative mechano-transducers. It is likely that alterations of skin mechanics in vivo underlying pathogenic processes like wound formation and healing trigger physiologic responses via the MAP kinase pathway.

  3. A Multi-Objective Approach to Visualize Proportions and Similarities Between Individuals by Rectangular Maps

    DEFF Research Database (Denmark)

    Carrizosa, Emilio; Guerrero, Vanesa; Morales, Dolores Romero

    In this paper we address the problem of visualizing the proportions and the similarities attached to a set of individuals. We represent this information using a rectangular map, i.e., a subdivision of a rectangle into rectangular portions so that each portion is associated with one individual, th...

  4. On Mathematical Optimization for the Visualization of Frequencies and Adjacencies as Rectangular Maps

    DEFF Research Database (Denmark)

    Carrizosa, Emilio; Guerrero, Vanesa; Morales, Dolores Romero

    2018-01-01

    In this paper we address the problem of visualizing a frequency distribution and an adjacency relation attached to a set of individuals. We represent this information using a rectangular map, i.e., a subdivision of a rectangle into rectangular portions so that each portion is associated with one ...

  5. Visual acuity and microperimetric mapping of lesion area in eyes with inflammatory cystoid macular oedema

    DEFF Research Database (Denmark)

    Munk, Marion R; Kiss, Christopher G; Huf, Wolfgang

    2014-01-01

    PURPOSE:   To evaluate the effect of fluid accumulation on local visual function in inflammatory cystoid-macular-edema (ICME). METHODS:   This cross-sectional study applied optical-coherence-tomography over a 12×12 fovea-centered field in 50 patients with ICME and mapped the extent of fluid-fille...

  6. Using Saliency Maps to Separate Competing Processes in Infant Visual Cognition

    Science.gov (United States)

    Althaus, Nadja; Mareschal, Denis

    2012-01-01

    This article presents an eye-tracking study using a novel combination of visual saliency maps and "area-of-interest" analyses to explore online feature extraction during category learning in infants. Category learning in 12-month-olds (N = 22) involved a transition from looking at high-saliency image regions to looking at more…

  7. Spatio-temporal flow maps for visualizing movement and contact patterns

    Directory of Open Access Journals (Sweden)

    Bing Ni

    2017-03-01

    Full Text Available The advanced telecom technologies and massive volumes of intelligent mobile phone users have yielded a huge amount of real-time data of people’s all-in-one telecommunication records, which we call telco big data. With telco data and the domain knowledge of an urban city, we are now able to analyze the movement and contact patterns of humans in an unprecedented scale. Flow map is widely used to display the movements of humans from one single source to multiple destinations by representing locations as nodes and movements as edges. However, it fails the task of visualizing both movement and contact data. In addition, analysts often need to compare and examine the patterns side by side, and do various quantitative analysis. In this work, we propose a novel spatio-temporal flow map layout to visualize when and where people from different locations move into the same places and make contact. We also propose integrating the spatiotemporal flow maps into existing spatiotemporal visualization techniques to form a suite of techniques for visualizing the movement and contact patterns. We report a potential application the proposed techniques can be applied to. The results show that our design and techniques properly unveil hidden information, while analysis can be achieved efficiently. Keywords: Spatio-temporal data, Flow map, Urban mobility

  8. Visualizing the Past: The Design of a Temporally Enabled Map for Presentation (TEMPO

    Directory of Open Access Journals (Sweden)

    Nathan Prestopnik

    2012-01-01

    Full Text Available We present a design case for a prototype visualization tool called the Temporally Enabled Map for Presentation (TEMPO. Designed for use in the lecture classroom, TEMPO is an interactive animated map that addressed a common problem in military history: the shortcomings of traditional static (non-interactive, non-animated maps. Static maps show spatial elements well, but cannot do more than approximate temporal events using multiple views, movement arrows, and the like. TEMPO provides a more complete view of past historical events by showing them from start to finish. In our design case we describe our development process, which included consultation with military history domain experts, classroom observations, application of techniques derived from visualization and Human-Computer Interaction (HCI literature and theory. Our design case shows how the design of an educational tool can motivate scholarly evaluation, and we describe how some theories were first embraced and then rejected as design circumstances required. Finally, we explore a future direction for TEMPO, tools to support creative interactions with visualizations where students or instructors can learn by visualizing historical events for themselves. A working version of the finished TEMPO artifact is included as an interactive element in this document.

  9. Estimation of Visual Maps with a Robot Network Equipped with Vision Sensors

    Directory of Open Access Journals (Sweden)

    Arturo Gil

    2010-05-01

    Full Text Available In this paper we present an approach to the Simultaneous Localization and Mapping (SLAM problem using a team of autonomous vehicles equipped with vision sensors. The SLAM problem considers the case in which a mobile robot is equipped with a particular sensor, moves along the environment, obtains measurements with its sensors and uses them to construct a model of the space where it evolves. In this paper we focus on the case where several robots, each equipped with its own sensor, are distributed in a network and view the space from different vantage points. In particular, each robot is equipped with a stereo camera that allow the robots to extract visual landmarks and obtain relative measurements to them. We propose an algorithm that uses the measurements obtained by the robots to build a single accurate map of the environment. The map is represented by the three-dimensional position of the visual landmarks. In addition, we consider that each landmark is accompanied by a visual descriptor that encodes its visual appearance. The solution is based on a Rao-Blackwellized particle filter that estimates the paths of the robots and the position of the visual landmarks. The validity of our proposal is demonstrated by means of experiments with a team of real robots in a office-like indoor environment.

  10. Retinotopic mapping of categorical and coordinate spatial relation processing in early visual cortex.

    Directory of Open Access Journals (Sweden)

    Ineke J M van der Ham

    Full Text Available Spatial relations are commonly divided in two global classes. Categorical relations concern abstract relations which define areas of spatial equivalence, whereas coordinate relations are metric and concern exact distances. Categorical and coordinate relation processing are thought to rely on at least partially separate neurocognitive mechanisms, as reflected by differential lateralization patterns, in particular in the parietal cortex. In this study we address this textbook principle from a new angle. We studied retinotopic activation in early visual cortex, as a reflection of attentional distribution, in a spatial working memory task with either a categorical or a coordinate instruction. Participants were asked to memorize a dot position, with regard to a central cross, and to indicate whether a subsequent dot position matched the first dot position, either categorically (opposite quadrant of the cross or coordinately (same distance to the centre of the cross. BOLD responses across the retinotopic maps of V1, V2, and V3 indicate that the spatial distribution of cortical activity was different for categorical and coordinate instructions throughout the retention interval; a more local focus was found during categorical processing, whereas focus was more global for coordinate processing. This effect was strongest for V3, approached significance in V2 and was absent in V1. Furthermore, during stimulus presentation the two instructions led to different levels of activation in V3 during stimulus encoding; a stronger increase in activity was found for categorical processing. Together this is the first demonstration that instructions for specific types of spatial relations may yield distinct attentional patterns which are already reflected in activity early in the visual cortex.

  11. Cognitive mechanisms underlying instructed choice exploration of small city maps

    Directory of Open Access Journals (Sweden)

    Sofia eSakellaridi

    2015-03-01

    Full Text Available We investigated the cognitive mechanisms underlying the exploration and decision-making in realistic and novel environments. Twelve human subjects were shown small circular U.S. city maps with two locations highlighted on the circumference, as possible choices for a post office (targets. At the beginning of a trial, subjects fixated a spot at the center of the map and ultimately chose one of the two locations. A space syntax analysis of the map paths (from the center to each target revealed that the chosen location was associated with the less convoluted path, as if subjects navigated mentally the paths in an ant’s way, i.e. by staying within street boundaries, and ultimately choosing the target that could be reached from the center in the shortest way, and the fewest turns and intersections. The subjects’ strategy for map exploration and decision making was investigated by monitoring eye position during the task. This revealed a restricted exploration of the map delimited by the location of the two alternative options and the center of the map. Specifically, subjects explored the areas around the two target options by repeatedly looking at them before deciding which one to choose, presumably implementing an evaluation and decision-making process. The ultimate selection of a specific target was significantly associated with the time spent exploring the area around that target. Finally, an analysis of the sequence of eye fixations revealed that subjects tended to look systematically towards the target ultimately chosen even from the beginning of the trial. This finding indicates an early cognitive selection bias for the ensuing decision process.

  12. Cognitive mechanisms underlying instructed choice exploration of small city maps.

    Science.gov (United States)

    Sakellaridi, Sofia; Christova, Peka; Christopoulos, Vassilios N; Vialard, Alice; Peponis, John; Georgopoulos, Apostolos P

    2015-01-01

    We investigated the cognitive mechanisms underlying the exploration and decision-making in realistic and novel environments. Twelve human subjects were shown small circular U.S. city maps with two locations highlighted on the circumference, as possible choices for a post office ("targets"). At the beginning of a trial, subjects fixated a spot at the center of the map and ultimately chose one of the two locations. A space syntax analysis of the map paths (from the center to each target) revealed that the chosen location was associated with the less convoluted path, as if subjects navigated mentally the paths in an "ant's way," i.e., by staying within street boundaries, and ultimately choosing the target that could be reached from the center in the shortest way, and the fewest turns and intersections. The subjects' strategy for map exploration and decision making was investigated by monitoring eye position during the task. This revealed a restricted exploration of the map delimited by the location of the two alternative options and the center of the map. Specifically, subjects explored the areas around the two target options by repeatedly looking at them before deciding which one to choose, presumably implementing an evaluation and decision-making process. The ultimate selection of a specific target was significantly associated with the time spent exploring the area around that target. Finally, an analysis of the sequence of eye fixations revealed that subjects tended to look systematically toward the target ultimately chosen even from the beginning of the trial. This finding indicates an early cognitive selection bias for the ensuing decision process.

  13. Non-uniform phase sensitivity in spatial frequency maps of the human visual cortex.

    Science.gov (United States)

    Farivar, Reza; Clavagnier, Simon; Hansen, Bruce C; Thompson, Ben; Hess, Robert F

    2017-02-15

    Just as a portrait painting can come from a collection of coarse and fine details, natural vision can be decomposed into coarse and fine components. Previous studies have shown that the early visual areas in the brain represent these components in a map-like fashion. Other studies have shown that these same visual areas can be sensitive to how coarse and fine features line up in space. We found that the brain actually jointly represents both the scale of the feature (fine, medium, or coarse) and the alignment of these features in space. The results suggest that the visual cortex has an optimized representation particularly for the alignment of fine details, which are crucial in understanding the visual scene. Complex natural scenes can be decomposed into their oriented spatial frequency (SF) and phase relationships, both of which are represented locally at the earliest stages of cortical visual processing. The SF preference map in the human cortex, obtained using synthetic stimuli, is orderly and correlates strongly with eccentricity. In addition, early visual areas show sensitivity to the phase information that describes the relationship between SFs and thereby dictates the structure of the image. Taken together, two possibilities arise for the joint representation of SF and phase: either the entirety of the cortical SF map is uniformly sensitive to phase, or a particular set of SFs is selectively phase sensitive - for example, greater phase sensitivity for higher SFs that define fine-scale edges in a complex scene. To test between these two possibilities, we constructed a novel continuous natural scene video whereby phase information was maintained in one SF band but scrambled elsewhere. By shifting the central frequency of the phase-aligned band in time, we mapped the phase-sensitive SF preference of the visual cortex. Using functional magnetic resonance imaging, we found that phase sensitivity in early visual areas is biased toward higher SFs. Compared to a SF

  14. Mapping the Isotropic Component of Focal Mechanisms in Hydraulic Fractures

    Science.gov (United States)

    Baig, A. M.; Urbancic, T. I.

    2009-12-01

    We present the results of a hydraulic fracture monitoring study where the events induced by the treatment are recorded with a three-dimensional sensor distribution. The fact that the microseismicity is recorded over multiple azimuths allows not only for better convergence of the location algorithm, but also acheives sufficient coverage of the focal sphere to reliably invert for the full moment tensor. Unlike in tectonic settings, many of these focal mechanisms have very strong non-double-couple components, due to the intrusion of proppants into the surrounding rock, and are thus characterized by mechanisms consistant with tensile cracks opening or closing. Mapping these mechanisms in time and space offers insight into both the processes responsible for the fracturing, but also how effectively the treatment propped open the rock and identifying which areas may have opened and subsequently closed.

  15. Neural mechanisms underlying temporal modulation of visual perception

    NARCIS (Netherlands)

    Jong, M.C. de

    2015-01-01

    However confident we feel about the way we perceive the visual world around us, there is not a one-to-one relation between visual stimulation and visual perception. Our eyes register reflections of the visual environment and our brain has the difficult task of constructing ‘reality’ from this

  16. A Visual-Based Approach for Indoor Radio Map Construction Using Smartphones.

    Science.gov (United States)

    Liu, Tao; Zhang, Xing; Li, Qingquan; Fang, Zhixiang

    2017-08-04

    Localization of users in indoor spaces is a common issue in many applications. Among various technologies, a Wi-Fi fingerprinting based localization solution has attracted much attention, since it can be easily deployed using the existing off-the-shelf mobile devices and wireless networks. However, the collection of the Wi-Fi radio map is quite labor-intensive, which limits its potential for large-scale application. In this paper, a visual-based approach is proposed for the construction of a radio map in anonymous indoor environments. This approach collects multi-sensor data, e.g., Wi-Fi signals, video frames, inertial readings, when people are walking in indoor environments with smartphones in their hands. Then, it spatially recovers the trajectories of people by using both visual and inertial information. Finally, it estimates the location of fingerprints from the trajectories and constructs a Wi-Fi radio map. Experiment results show that the average location error of the fingerprints is about 0.53 m. A weighted k-nearest neighbor method is also used to evaluate the constructed radio map. The average localization error is about 3.2 m, indicating that the quality of the constructed radio map is at the same level as those constructed by site surveying. However, this approach can greatly reduce the human labor cost, which increases the potential for applying it to large indoor environments.

  17. Visual indication of mechanical damage using core-shell microcapsules.

    Science.gov (United States)

    Odom, Susan A; Jackson, Aaron C; Prokup, Alex M; Chayanupatkul, Sarut; Sottos, Nancy R; White, Scott R; Moore, Jeffrey S

    2011-12-01

    We report a new core-shell microcapsule system for the visual detection of mechanical damage. The core material, 1,3,5,7-cyclooctatetraene, is a conjugated cyclic olefin and a precursor to intensely colored polyacetylene. A combination of poly(urea-formaldehyde) and polyurethane is required to effectively encapsulate the volatile core material. Increasing the outer shell wall thickness and including a core-side prepolymer improves the thermal stability and free-flowing nature of these capsules, which tend to leach and rupture with thinner shell walls. Capsules ruptured in the presence of the Grubbs-Love ruthenium catalyst show immediate color change from nearly colorless to red-orange and dark purple over time, and color change in thin films resulted from scratch damage. © 2011 American Chemical Society

  18. Personal sleep pattern visualization using sequence-based kernel self-organizing map on sound data.

    Science.gov (United States)

    Wu, Hongle; Kato, Takafumi; Yamada, Tomomi; Numao, Masayuki; Fukui, Ken-Ichi

    2017-07-01

    We propose a method to discover sleep patterns via clustering of sound events recorded during sleep. The proposed method extends the conventional self-organizing map algorithm by kernelization and sequence-based technologies to obtain a fine-grained map that visualizes the distribution and changes of sleep-related events. We introduced features widely applied in sound processing and popular kernel functions to the proposed method to evaluate and compare performance. The proposed method provides a new aspect of sleep monitoring because the results demonstrate that sound events can be directly correlated to an individual's sleep patterns. In addition, by visualizing the transition of cluster dynamics, sleep-related sound events were found to relate to the various stages of sleep. Therefore, these results empirically warrant future study into the assessment of personal sleep quality using sound data. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Preclinical medical students' understandings of academic and medical professionalism: visual analysis of mind maps.

    Science.gov (United States)

    Janczukowicz, Janusz; Rees, Charlotte E

    2017-08-18

    Several studies have begun to explore medical students' understandings of professionalism generally and medical professionalism specifically. Despite espoused relationships between academic (AP) and medical professionalism (MP), previous research has not yet investigated students' conceptualisations of AP and MP and the relationships between the two. The current study, based on innovative visual analysis of mind maps, therefore aims to contribute to the developing literature on how professionalism is understood. We performed a multilayered analysis of 98 mind maps from 262 first-year medical students, including analysing textual and graphical elements of AP, MP and the relationships between AP and MP. The most common textual attributes of AP were learning, lifestyle and personality, while attributes of MP were knowledge, ethics and patient-doctor relations. Images of books, academic caps and teachers were used most often to represent AP, while images of the stethoscope, doctor and red cross were used to symbolise MP. While AP-MP relations were sometimes indicated through co-occurring text, visual connections and higher-order visual metaphors, many students struggled to articulate the relationships between AP and MP. While the mind maps' textual attributes shared similarities with those found in previous research, suggesting the universality of some professionalism attributes, our study provides new insights into students' conceptualisations of AP, MP and AP-MP relationships. We encourage medical educators to help students develop their understandings of AP, MP and AP-MP relationships, plus consider the feasibility and value of mind maps as a source of visual data for medical education research. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. A studyforrest extension, retinotopic mapping and localization of higher visual areas

    OpenAIRE

    Sengupta, Ayan; Kaule, Falko R.; Guntupalli, J. Swaroop; Hoffmann, Michael B.; Häusler, Christian; Stadler, Jörg; Hanke, Michael

    2016-01-01

    The studyforrest (http://studyforrest.org) dataset is likely the largest neuroimaging dataset on natural language and story processing publicly available today. In this article, along with a companion publication, we present an update of this dataset that extends its scope to vision and multi-sensory research. 15 participants of the original cohort volunteered for a series of additional studies: a clinical examination of visual function, a standard retinotopic mapping procedure, and a localiz...

  1. Auditory and visual space maps in the cholinergic nucleus isthmi pars parvocellularis of the barn owl.

    Science.gov (United States)

    Maczko, Kristin A; Knudsen, Phyllis F; Knudsen, Eric I

    2006-12-06

    The nucleus isthmi pars parvocellularis (Ipc) is a midbrain cholinergic nucleus that shares reciprocal, topographic connections with the optic tectum (OT). Ipc neurons project to spatially restricted columns in the OT, contacting essentially all OT layers in a given column. Previous research characterizes the Ipc as a visual processor. We found that, in the barn owl, the Ipc responds to auditory as well as to visual stimuli. Auditory responses were tuned broadly for frequency, but sharply for spatial cues. We measured the tuning of Ipc units to binaural sound localization cues, including interaural timing differences (ITDs) and interaural level differences (ILDs). Units in the Ipc were tuned to specific values of both ITD and ILD and were organized systematically according to their ITD and ILD tuning, forming a map of space. The auditory space map aligned with the visual space map in the Ipc. These results demonstrate that the Ipc encodes the spatial location of objects, independent of stimulus modality. These findings, combined with the precise pattern of projections from the Ipc to the OT, suggest that the role of the Ipc is to regulate the sensitivity of OT neurons in a space-specific manner.

  2. Mapping language to visual referents: Does the degree of image realism matter?

    Science.gov (United States)

    Saryazdi, Raheleh; Chambers, Craig G

    2017-11-15

    Studies of real-time spoken language comprehension have shown that listeners rapidly map unfolding speech to available referents in the immediate visual environment. This has been explored using various kinds of 2-dimensional (2D) stimuli, with convenience or availability typically motivating the choice of a particular image type. However, work in other areas has suggested that certain cognitive processes are sensitive to the level of realism in 2D representations. The present study examined the process of mapping language to depictions of objects that are more or less realistic, namely photographs versus clipart images. A custom stimulus set was first created by generating clipart images directly from photographs of real objects. Two visual world experiments were then conducted, varying whether referent identification was driven by noun or verb information. A modest benefit for clipart stimuli was observed during real-time processing, but only for noun-driving mappings. The results are discussed in terms of their implications for studies of visually situated language processing. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  3. Model-based Real-time Visualization of Realistic Three-Dimensional Heat Maps for Mobile Eye Tracking and Eye Tracking in Virtual Reality

    OpenAIRE

    Pfeiffer, Thies; Memili, Cem

    2016-01-01

    Heat maps, or more generally, attention maps or saliency maps are an often used technique to visualize eye-tracking data. With heat maps qualitative information about visual processing can be easily visualized and communicated between experts and laymen. They are thus a versatile tool for many disciplines, in particular for usability engineering, and are often used to get a first overview about recorded eye-tracking data. Today, heat maps are typically generated for 2D stimuli that have b...

  4. Visual maps in the adult primate cerebral cortex: some implications for brain development and evolution

    Directory of Open Access Journals (Sweden)

    M.G.P. Rosa

    2002-12-01

    Full Text Available In this paper, the topology of cortical visuotopic maps in adult primates is reviewed, with emphasis on recent studies. The observed visuotopic organisation can be summarised with reference to two basic rules. First, adjacent radial columns in the cortex represent partially overlapping regions of the visual field, irrespective of whether these columns are part of the same or different cortical areas. This primary rule is seldom, if ever, violated. Second, adjacent regions of the visual field tend to be represented in adjacent radial columns of a same area. This rule is not as rigid as the first, as many cortical areas form discontinuous, second-order representations of the visual field. A developmental model based on these physiological observations, and on comparative studies of cortical organisation, is then proposed, in order to explain how a combination of molecular specification steps and activity-driven processes can generate the variety of visuotopic organisations observed in adult cortex.

  5. Pairwise-Distance-Analysis-Driven Dimensionality Reduction Model with Double Mappings for Hyperspectral Image Visualization

    Directory of Open Access Journals (Sweden)

    Yi Long

    2015-06-01

    Full Text Available This paper describes a novel strategy for the visualization of hyperspectral imagery based on the analysis of image pixel pairwise distances. The goal of this approach is to generate a final color image with excellent interpretability and high contrast at the cost of distorting a few pairwise distances. Specifically, the principle of equal variance is introduced to divide all hyperspectral bands into three subgroups and to ensure the energy is distributed uniformly between them, as in natural color images. Then, after detecting both normal and outlier pixels, these three subgroups are mapped into three color components of the output visualization using two different mapping (i.e., dimensionality reduction schemes for the two types of pixels. The widely-used multidimensional scaling (MDS is used for normal pixels and a new objective function, taking into account the weighting of pairwise distances, is presented for the outlier pixels. The pairwise distance weighting is designed such that small pairwise distances between the outliers and their respective neighbors are emphasized and large deviations are suppressed. This produces an image with high contrast and good interpretability while retaining the detailed information content. The proposed algorithm is compared with several state-of-the-art visualization techniques and evaluated on the well-known AVIRIS hyperspectral images. The effectiveness of the proposed strategy is substantiated both visually and quantitatively.

  6. Mapping of Mechanical Strains and Stresses around Quiescent Engineered Three-Dimensional Epithelial Tissues

    Science.gov (United States)

    Gjorevski, Nikolce; Nelson, Celeste M.

    2012-01-01

    Understanding how physical signals guide biological processes requires qualitative and quantitative knowledge of the mechanical forces generated and sensed by cells in a physiologically realistic three-dimensional (3D) context. Here, we used computational modeling and engineered epithelial tissues of precise geometry to define the experimental parameters that are required to measure directly the mechanical stress profile of 3D tissues embedded within native type I collagen. We found that to calculate the stresses accurately in these settings, we had to account for mechanical heterogeneities within the matrix, which we visualized and quantified using confocal reflectance and atomic force microscopy. Using this technique, we were able to obtain traction forces at the epithelium-matrix interface, and to resolve and quantify patterns of mechanical stress throughout the surrounding matrix. We discovered that whereas single cells generate tension by contracting and pulling on the matrix, the contraction of multicellular tissues can also push against the matrix, causing emergent compression. Furthermore, tissue geometry defines the spatial distribution of mechanical stress across the epithelium, which communicates mechanically over distances spanning hundreds of micrometers. Spatially resolved mechanical maps can provide insight into the types and magnitudes of physical parameters that are sensed and interpreted by multicellular tissues during normal and pathological processes. PMID:22828342

  7. A tone mapping operator based on neural and psychophysical models of visual perception

    Science.gov (United States)

    Cyriac, Praveen; Bertalmio, Marcelo; Kane, David; Vazquez-Corral, Javier

    2015-03-01

    High dynamic range imaging techniques involve capturing and storing real world radiance values that span many orders of magnitude. However, common display devices can usually reproduce intensity ranges only up to two to three orders of magnitude. Therefore, in order to display a high dynamic range image on a low dynamic range screen, the dynamic range of the image needs to be compressed without losing details or introducing artefacts, and this process is called tone mapping. A good tone mapping operator must be able to produce a low dynamic range image that matches as much as possible the perception of the real world scene. We propose a two stage tone mapping approach, in which the first stage is a global method for range compression based on a gamma curve that equalizes the lightness histogram the best, and the second stage performs local contrast enhancement and color induction using neural activity models for the visual cortex.

  8. Limb position drift results from misalignment of proprioceptive and visual maps.

    Science.gov (United States)

    Patterson, Jacqueline R; Brown, Liana E; Wagstaff, David A; Sainburg, Robert L

    2017-03-27

    Previous work (Brown et al., 2003a,b) has shown that limb position drifts when individuals make repetitive movements in the absence of visual feedback. The purpose of this study was to examine whether limb position drift might reflect a misalignment in visual and proprioceptive maps by examining the nature of information used to specify new movements from a drifted limb position. In a virtual reality (VR) environment, participants made continuous movements with their dominant right hand between two targets positioned 15cm apart, paced by a 0.625-Hz metronome. After 5 cycles, cursor feedback of the hand was removed for the next 44 cycles, which induced an average drift in hand position of roughly 5cm. On the 50th cycle, participants were required to move to one of 6 new targets from the drifted hand position. Kinematic analysis indicated that movement direction was unambiguously determined by the visual input marked by the original start position, or the last-seen hand position. Forward dynamics analysis revealed that current limb configuration was used to inform joint torques to produce this parallel direction. For new movement specification, accurate proprioceptive information about the drifted limb position was used, even though it was apparently not available for detecting drift in the first place. Movement distance varied directly with the extent of limb drift, although the differentiation of visual and proprioceptive control of distance could not be analyzed, as our control conditions were not significantly different for this measure. We suggest that movement drift, in the absence of visual feedback during cyclic repetitive movements, reflects a misalignment between largely accurate visual and proprioceptive maps, rather than a weighted fusion of the two modalities. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. An Information-Theoretic-Cluster Visualization for Self-Organizing Maps.

    Science.gov (United States)

    Brito da Silva, Leonardo Enzo; Wunsch, Donald C

    2017-05-17

    Improved data visualization will be a significant tool to enhance cluster analysis. In this paper, an information-theoretic-based method for cluster visualization using self-organizing maps (SOMs) is presented. The information-theoretic visualization (IT-vis) has the same structure as the unified distance matrix, but instead of depicting Euclidean distances between adjacent neurons, it displays the similarity between the distributions associated with adjacent neurons. Each SOM neuron has an associated subset of the data set whose cardinality controls the granularity of the IT-vis and with which the first- and second-order statistics are computed and used to estimate their probability density functions. These are used to calculate the similarity measure, based on Renyi's quadratic cross entropy and cross information potential (CIP). The introduced visualizations combine the low computational cost and kernel estimation properties of the representative CIP and the data structure representation of a single-linkage-based grouping algorithm to generate an enhanced SOM-based visualization. The visual quality of the IT-vis is assessed by comparing it with other visualization methods for several real-world and synthetic benchmark data sets. Thus, this paper also contains a significant literature survey. The experiments demonstrate the IT-vis cluster revealing capabilities, in which cluster boundaries are sharply captured. Additionally, the information-theoretic visualizations are used to perform clustering of the SOM. Compared with other methods, IT-vis of large SOMs yielded the best results in this paper, for which the quality of the final partitions was evaluated using external validity indices.

  10. Preclinical medical students’ understandings of academic and medical professionalism: visual analysis of mind maps

    Science.gov (United States)

    Rees, Charlotte E

    2017-01-01

    Introduction Several studies have begun to explore medical students’ understandings of professionalism generally and medical professionalism specifically. Despite espoused relationships between academic (AP) and medical professionalism (MP), previous research has not yet investigated students’ conceptualisations of AP and MP and the relationships between the two. Objectives The current study, based on innovative visual analysis of mind maps, therefore aims to contribute to the developing literature on how professionalism is understood. Methods We performed a multilayered analysis of 98 mind maps from 262 first-year medical students, including analysing textual and graphical elements of AP, MP and the relationships between AP and MP. Results The most common textual attributes of AP were learning, lifestyle and personality, while attributes of MP were knowledge, ethics and patient-doctor relations. Images of books, academic caps and teachers were used most often to represent AP, while images of the stethoscope, doctor and red cross were used to symbolise MP. While AP-MP relations were sometimes indicated through co-occurring text, visual connections and higher-order visual metaphors, many students struggled to articulate the relationships between AP and MP. Conclusions While the mind maps’ textual attributes shared similarities with those found in previous research, suggesting the universality of some professionalism attributes, our study provides new insights into students’ conceptualisations of AP, MP and AP-MP relationships. We encourage medical educators to help students develop their understandings of AP, MP and AP-MP relationships, plus consider the feasibility and value of mind maps as a source of visual data for medical education research. PMID:28821520

  11. See what we say: using concept mapping to visualize Latino immigrant's strategies for health interventions.

    Science.gov (United States)

    Vaughn, Lisa M; Jacquez, Farrah; Marschner, Daniel; McLinden, Daniel

    2016-09-01

    Researchers need specific tools to engage community members in health intervention development to ensure that efforts are contextually appropriate for immigrant populations. The purpose of the study was to generate and prioritize strategies to address obesity, stress and coping, and healthcare navigation that are contextually appropriate and applicable to the Latino immigrant community in Cincinnati, Ohio, and then use the results to develop specific interventions to improve Latino health in our area. A community-academic research team used concept mapping methodology with over 200 Latino immigrants and Latino-serving providers. A community intervention planning session was held to share the final concept maps and vote on strategies. The concept maps and results from the intervention planning session emphasized a community lay health worker model to connect the Latino immigrant community with resources to address obesity, stress and coping, and healthcare navigation. Concept maps allowed for the visualization of health intervention strategies prioritized by the larger Latino immigrant community. Concept maps revealed the appropriate content for health interventions as well as the process community members preferred for intervention delivery.

  12. Quantitative Mapping of Mechanisms for Photoinitiated Coating Degradation

    DEFF Research Database (Denmark)

    Kiil, Søren

    2015-01-01

    This work concerns the mathematical modeling of photoinitiated coating degradation. Using experimental evidence available, some of the most importantassumptions underlying existing models for the rmoset coatings are analyzed and suggestions for further work provided. A modeling approach that can...... be used toimplement the various effects of water on the degradation mechanisms of cross-linked coatings is also presented and experiments to test the approach are suggested. Additionally, simulations with an existing degradation model for an epoxy–amine coating are used to map the influence of model...... parameters on the lag time (i.e., the time passing prior to the onset of erosion) and the stable erosion rate. The simulation results can be used in the optimization of UV radiation-induced intercoat adhesion losses, which are often observed in multilayer coating systems based on top coated epoxy coatings...

  13. The feasibility of an infrared system for real-time visualization and mapping of ultrasound fields

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Adam; Nunn, John, E-mail: adam.shaw@npl.co.u [National Physical Laboratory, Teddington, Middlesex, TW11 0LW (United Kingdom)

    2010-06-07

    In treatment planning for ultrasound therapy, it is desirable to know the 3D structure of the ultrasound field. However, mapping an ultrasound field in 3D is very slow, with even a single planar raster scan taking typically several hours. Additionally, hydrophones that are used for field mapping are expensive and can be damaged in some therapy fields. So there is value in rapid methods which enable visualization and mapping of the ultrasound field in about 1 min. In this note we explore the feasibility of mapping the intensity distribution by measuring the temperature distribution produced in a thin sheet of absorbing material. A 0.2 mm thick acetate sheet forms a window in the wall of a water tank containing the transducer. The window is oriented at 45{sup 0} to the beam axis, and the distance from the transducer to the window can be varied. The temperature distribution is measured with an infrared camera; thermal images of the inclined plane could be viewed in real time or images could be captured for later analysis and 3D field reconstruction. We conclude that infrared thermography can be used to gain qualitative information about ultrasound fields. Thermal images are easily visualized with good spatial and thermal resolutions (0.044 mm and 0.05 {sup 0}C in our system). The focus and field structure such as side lobes can be identified in real time from the direct video output. 3D maps and image planes at arbitrary orientations to the beam axis can be obtained and reconstructed within a few minutes. In this note we are primarily interested in the technique for characterization of high intensity focused ultrasound (HIFU) fields, but other applications such as physiotherapy fields are also possible. (note)

  14. Mapping and Visualization of the Distribution of Scientific Wealth in Iran

    Directory of Open Access Journals (Sweden)

    Saeid Asadi

    2014-02-01

    Full Text Available This research addresses the issues of measuring the geographic distribution of scientific wealth in Iranian provinces. It focuses on mapping and visualization of scientific production and use in the country. The share of each province in the national scientific wealth of Iran has been measured through counting the documents indexed and retrieved from IRANDOC bibliographic databases. The seven specialized databases of IRANDOC include journal articles, conference articles, theses, governmental reports and so on consisting over half a million bibliographic records. Dividing the provinces in three classes of poor, average and rich according to their contribution in Iranian scientific wealth, Tehran and Isfahan provinces were tagged as the richest. A comprehensive description on developing a GIS model to visualize the distribution of scientific wealth in Iran is given in the paper and results are interpreted. In each case, the search results have analyzed more via a post-query spatial analysis for extraction of locations and comparing the extracted locations with a national gazetteer in order to find the proper province(s for each single retrieved record. Using an interactive map, the share of each province in the retrieved results was illustrated on map and compared with the other provinces. It has been noticed that a combination of online or offline interactive maps e.g. Google Maps and Google Earth and geographically tagged bibliographic data can result in a location-aware search and retrieval tool where in-depth analysis of search results will be possible. The outcomes of this research can be used in planning for sustainable and balanced development of the country.

  15. Digital administrative maps – A tool for visualization of epidemiological data

    Directory of Open Access Journals (Sweden)

    Ewa Niewiadomska

    2013-08-01

    Full Text Available Background: The aim of the study is to present the methods for visualization of epidemiological data using digital contour maps that take into account administrative division of Poland. Materials and Methods: The possibility of epidemiological data visualization in a geographical order, limited to the administrative level of the country, voivodeships and poviats (counties, are presented. They are crucial for the process of identifying and undertaking adequate prophylactic activities directed towards decreasing the risk and improving the population's health. This paper presents tools and techniques available in Geographic Information System ArcGIS and statistical software package R. Results: The work includes our own data reflecting: 1 the values of specific mortality rates due to respiratory diseases, Poland, 2010, based on the Central Statistical Office data, using the R statistical software package; 2 the averaged registered incidence rates of sarcoidosis in 2006-2010 for the population aged 19+ in the Silesian voivodeship, using Geographic Information System ArcGIS; and 3 the number of children with diagnosed respiratory diseases in the city of Legnica in 2009, taking into account their place of residence, using layered maps in Geographic Information System ArcGIS. Conclusions: The tools presented and described in this paper make it possible to visualize the results of research, to increase attractiveness of courses for students, as well as to enhance the skills and competence of students and participants of courses. Med Pr 2013;64(4:533–539

  16. Visual Overlay on OpenStreetMap Data to Support Spatial Exploration of Urban Environments

    Directory of Open Access Journals (Sweden)

    Chandan Kumar

    2015-01-01

    Full Text Available Increasing volumes of spatial data about urban areas are captured and made available via volunteered geographic information (VGI sources, such as OpenStreetMap (OSM. Hence, new opportunities arise for regional exploration that can lead to improvements in the lives of citizens through spatial decision support. We believe that the VGI data of the urban environment could be used to present a constructive overview of the regional infrastructure with the advent of web technologies. Current location-based services provide general map-based information for the end users with conventional local search functionality, and hence, the presentation of the rich urban information is limited. In this work, we analyze the OSM data to classify the geo entities into consequential categories with facilities, landscape and land use distribution. We employ a visual overlay of heat map and interactive visualizations to present the regional characterization on OSM data classification. In the proposed interface, users are allowed to express a variety of spatial queries to exemplify their geographic interests. They can compare the characterization of urban areas with respect to multiple spatial dimensions of interest and can search for the most suitable region. The search experience is further enhanced via efficient optimization and interaction methods to support the decision making of end users. We report the end user acceptability and efficiency of the proposed system via usability studies and performance analysis comparison.

  17. A visualization environment for supercomputing-based applications in computational mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Pavlakos, C.J.; Schoof, L.A.; Mareda, J.F.

    1993-06-01

    In this paper, we characterize a visualization environment that has been designed and prototyped for a large community of scientists and engineers, with an emphasis in superconducting-based computational mechanics. The proposed environment makes use of a visualization server concept to provide effective, interactive visualization to the user`s desktop. Benefits of using the visualization server approach are discussed. Some thoughts regarding desirable features for visualization server hardware architectures are also addressed. A brief discussion of the software environment is included. The paper concludes by summarizing certain observations which we have made regarding the implementation of such visualization environments.

  18. Using Route and Survey Information to Generate Cognitive Maps : Differences Between Normally Sighted and Visually Impaired Individuals

    NARCIS (Netherlands)

    Steyvers, Frank J. J. M.; Kooijman, Aart C.

    Visually impaired people (VIP) have to rely on different information to generate a cognitive map of their environment than normally sighted people. This study explored the extent to which a cognitive map could be generated by auditory information of route-type and survey-type descriptions of a

  19. An interactive mapping tool for visualizing lacunarity of laser scanned point clouds

    Science.gov (United States)

    Kania, Adam; Székely, Balázs

    2016-04-01

    Lacunarity, a measure of the spatial distribution of the empty space in a certain model or real space over large spatial scales, is found to be a useful descriptive quantity in many fields using imagery, including, among others, geology, dentistry, neurology. Its application in ecology was suggested more than 20 years ago. The main problem of its application was the lack of appropriate high resolution data. Nowadays, full-waveform laser scanning, also known as FWF LiDAR, provides the tool for mapping the vegetation in unprecedented details and accuracy. Consequently, the lacunarity concept can be revitalized, in order to study the structure of the vegetation in this sense as well. Calculation of lacunarity, even if it is done in two dimensions (2D), is still has its problems: on one hand it is a number-crunching procedure, on the other hand, it produces 4D results: at each 3D point it returns a set of data that are function of scale. These data sets are difficult to visualize, to evaluate, and to compare. In order to solve this problem, an interactive mapping tool has been conceptualized that is designed to manipulate and visualize the data, lets the user set parameters for best visualization or comparison results. The system is able to load large amounts of data, visualize them as lacunarity curves, or map view as horizontal slices or in 3D point clouds coloured according to the user's choice. Lacunarity maps are presented as a series of (usually) horizontal profiles, e.g. rasters, which cells contain color-mapped values of selected lacunarity of the point cloud. As lacunarity is usually analysed in a series of successive windows sizes, the tool can show a series of rasters with sequentially animated lacunarity maps calculated for various window sizes. A very fast switching of colour schemes is possible to facilitate rapid visual feedback to better understand underlying data patterns exposed by lacunarity functions. In the comparison mode, two sites (or two areas

  20. SBGNViz: A Tool for Visualization and Complexity Management of SBGN Process Description Maps.

    Directory of Open Access Journals (Sweden)

    Mecit Sari

    Full Text Available Information about cellular processes and pathways is becoming increasingly available in detailed, computable standard formats such as BioPAX and SBGN. Effective visualization of this information is a key recurring requirement for biological data analysis, especially for -omic data. Biological data analysis is rapidly migrating to web based platforms; thus there is a substantial need for sophisticated web based pathway viewers that support these platforms and other use cases.Towards this goal, we developed a web based viewer named SBGNViz for process description maps in SBGN (SBGN-PD. SBGNViz can visualize both BioPAX and SBGN formats. Unique features of SBGNViz include the ability to nest nodes to arbitrary depths to represent molecular complexes and cellular locations, automatic pathway layout, editing and highlighting facilities to enable focus on sub-maps, and the ability to inspect pathway members for detailed information from EntrezGene. SBGNViz can be used within a web browser without any installation and can be readily embedded into web pages. SBGNViz has two editions built with ActionScript and JavaScript. The JavaScript edition, which also works on touch enabled devices, introduces novel methods for managing and reducing complexity of large SBGN-PD maps for more effective analysis.SBGNViz fills an important gap by making the large and fast-growing corpus of rich pathway information accessible to web based platforms. SBGNViz can be used in a variety of contexts and in multiple scenarios ranging from visualization of the results of a single study in a web page to building data analysis platforms.

  1. SBGNViz: A Tool for Visualization and Complexity Management of SBGN Process Description Maps.

    Science.gov (United States)

    Sari, Mecit; Bahceci, Istemi; Dogrusoz, Ugur; Sumer, Selcuk Onur; Aksoy, Bülent Arman; Babur, Özgün; Demir, Emek

    2015-01-01

    Information about cellular processes and pathways is becoming increasingly available in detailed, computable standard formats such as BioPAX and SBGN. Effective visualization of this information is a key recurring requirement for biological data analysis, especially for -omic data. Biological data analysis is rapidly migrating to web based platforms; thus there is a substantial need for sophisticated web based pathway viewers that support these platforms and other use cases. Towards this goal, we developed a web based viewer named SBGNViz for process description maps in SBGN (SBGN-PD). SBGNViz can visualize both BioPAX and SBGN formats. Unique features of SBGNViz include the ability to nest nodes to arbitrary depths to represent molecular complexes and cellular locations, automatic pathway layout, editing and highlighting facilities to enable focus on sub-maps, and the ability to inspect pathway members for detailed information from EntrezGene. SBGNViz can be used within a web browser without any installation and can be readily embedded into web pages. SBGNViz has two editions built with ActionScript and JavaScript. The JavaScript edition, which also works on touch enabled devices, introduces novel methods for managing and reducing complexity of large SBGN-PD maps for more effective analysis. SBGNViz fills an important gap by making the large and fast-growing corpus of rich pathway information accessible to web based platforms. SBGNViz can be used in a variety of contexts and in multiple scenarios ranging from visualization of the results of a single study in a web page to building data analysis platforms.

  2. Vector model for mapping of visual space to subjective 4-D sphere

    Science.gov (United States)

    Matuzevicius, Dalius; Vaitkevicius, Henrikas

    2014-03-01

    Here we present a mathematical model of binocular vision that maps a visible physical world to a subjective perception of it. The subjective space is a set of 4-D vectors whose components are outputs of four monocular neurons from each of the two eyes. Monocular neurons have one of the four types of concentric receptive fields with Gabor-like weighting coefficients. Next this vector representation of binocular vision is implemented as a pool of neurons where each of them is selective to the object's particular location in a 3-D visual space. Formally each point of the visual space is being projected onto a 4-D sphere. Proposed model allows determination of subjective distances in depth and direction, provides computational means for determination of Panum's area and explains diplopia and allelotropia.

  3. Eph receptor tyrosine kinase-mediated formation of a topographic map in the Drosophila visual system.

    Science.gov (United States)

    Dearborn, Richard; He, Qi; Kunes, Sam; Dai, Yong

    2002-02-15

    Roles for Eph receptor tyrosine kinase signaling in the formation of topographic patterns of axonal connectivity have been well established in vertebrate visual systems. Here we describe a role for a Drosophila Eph receptor tyrosine kinase (EPH) in the control of photoreceptor axon and cortical axon topography in the developing visual system. Although uniform across the developing eye, EPH is expressed in a concentration gradient appropriate for conveying positional information during cortical axon guidance in the second-order optic ganglion, the medulla. Disruption of this graded pattern of EPH activity by double-stranded RNA interference or by ectopic expression of wild-type or dominant-negative transgenes perturbed the establishment of medulla cortical axon topography. In addition, abnormal midline fasciculation of photoreceptor axons resulted from the eye-specific expression of the dominant-negative EPH transgene. These observations reveal a conserved role for Eph kinases as determinants of topographic map formation in vertebrates and invertebrates.

  4. Exploiting data topology in visualization and clustering of self-organizing maps.

    Science.gov (United States)

    Taşdemir, Kadim; Merényi, Erzsébet

    2009-04-01

    The self-organizing map (SOM) is a powerful method for visualization, cluster extraction, and data mining. It has been used successfully for data of high dimensionality and complexity where traditional methods may often be insufficient. In order to analyze data structure and capture cluster boundaries from the SOM, one common approach is to represent the SOM's knowledge by visualization methods. Different aspects of the information learned by the SOM are presented by existing methods, but data topology, which is present in the SOM's knowledge, is greatly underutilized. We show in this paper that data topology can be integrated into the visualization of the SOM and thereby provide a more elaborate view of the cluster structure than existing schemes. We achieve this by introducing a weighted Delaunay triangulation (a connectivity matrix) and draping it over the SOM. This new visualization, CONNvis, also shows both forward and backward topology violations along with the severity of forward ones, which indicate the quality of the SOM learning and the data complexity. CONNvis greatly assists in detailed identification of cluster boundaries. We demonstrate the capabilities on synthetic data sets and on a real 8-D remote sensing spectral image.

  5. NeuroLines: A Subway Map Metaphor for Visualizing Nanoscale Neuronal Connectivity

    KAUST Repository

    Al-Awami, Ali K.

    2014-12-31

    We present NeuroLines, a novel visualization technique designed for scalable detailed analysis of neuronal connectivity at the nanoscale level. The topology of 3D brain tissue data is abstracted into a multi-scale, relative distance-preserving subway map visualization that allows domain scientists to conduct an interactive analysis of neurons and their connectivity. Nanoscale connectomics aims at reverse-engineering the wiring of the brain. Reconstructing and analyzing the detailed connectivity of neurons and neurites (axons, dendrites) will be crucial for understanding the brain and its development and diseases. However, the enormous scale and complexity of nanoscale neuronal connectivity pose big challenges to existing visualization techniques in terms of scalability. NeuroLines offers a scalable visualization framework that can interactively render thousands of neurites, and that supports the detailed analysis of neuronal structures and their connectivity. We describe and analyze the design of NeuroLines based on two real-world use-cases of our collaborators in developmental neuroscience, and investigate its scalability to large-scale neuronal connectivity data.

  6. Visual assessment of BIPV retrofit design proposals for selected historical buildings using the saliency map method

    Directory of Open Access Journals (Sweden)

    Ran Xu

    2015-06-01

    Full Text Available With the increasing awareness of energy efficiency, many old buildings have to undergo a massive facade energy retrofit. How to predict the visual impact which solar installations on the aesthetic cultural value of these buildings has been a heated debate in Switzerland (and throughout the world. The usual evaluation method to describe the visual impact of BIPV is based on semantic and qualitative descriptors, and strongly dependent on personal preferences. The evaluation scale is therefore relative, flexible and imprecise. This paper proposes a new method to accurately measure the visual impact which BIPV installations have on a historical building by using the saliency map method. By imitating working principles of the human eye, it is measured how much the BIPV design proposals differ from the original building facade in the aspect of attracting human visual attention. The result is directly presented in a quantitative manner, and can be used to compare the fitness of different BIPV design proposals. The measuring process is numeric, objective and more precise.  

  7. Infrared and visible image fusion based on visual saliency map and weighted least square optimization

    Science.gov (United States)

    Ma, Jinlei; Zhou, Zhiqiang; Wang, Bo; Zong, Hua

    2017-05-01

    The goal of infrared (IR) and visible image fusion is to produce a more informative image for human observation or some other computer vision tasks. In this paper, we propose a novel multi-scale fusion method based on visual saliency map (VSM) and weighted least square (WLS) optimization, aiming to overcome some common deficiencies of conventional methods. Firstly, we introduce a multi-scale decomposition (MSD) using the rolling guidance filter (RGF) and Gaussian filter to decompose input images into base and detail layers. Compared with conventional MSDs, this MSD can achieve the unique property of preserving the information of specific scales and reducing halos near edges. Secondly, we argue that the base layers obtained by most MSDs would contain a certain amount of residual low-frequency information, which is important for controlling the contrast and overall visual appearance of the fused image, and the conventional "averaging" fusion scheme is unable to achieve desired effects. To address this problem, an improved VSM-based technique is proposed to fuse the base layers. Lastly, a novel WLS optimization scheme is proposed to fuse the detail layers. This optimization aims to transfer more visual details and less irrelevant IR details or noise into the fused image. As a result, the fused image details would appear more naturally and be suitable for human visual perception. Experimental results demonstrate that our method can achieve a superior performance compared with other fusion methods in both subjective and objective assessments.

  8. High impact data visualization with Power View, Power Map, and Power BI

    CERN Document Server

    Aspin, Adam

    2014-01-01

    High Impact Data Visualization with Power View, Power Map, and Power BI helps you take business intelligence delivery to a new level that is interactive, engaging, even fun, all while driving commercial success through sound decision-making. Learn to harness the power of Microsoft's flagship, self-service business intelligence suite to deliver compelling and interactive insight with remarkable ease. Learn the essential techniques needed to enhance the look and feel of reports and dashboards so that you can seize your audience's attention and provide them with clear and accurate information. Al

  9. HealthMap: global infectious disease monitoring through automated classification and visualization of Internet media reports.

    Science.gov (United States)

    Freifeld, Clark C; Mandl, Kenneth D; Reis, Ben Y; Brownstein, John S

    2008-01-01

    Unstructured electronic information sources, such as news reports, are proving to be valuable inputs for public health surveillance. However, staying abreast of current disease outbreaks requires scouring a continually growing number of disparate news sources and alert services, resulting in information overload. Our objective is to address this challenge through the HealthMap.org Web application, an automated system for querying, filtering, integrating and visualizing unstructured reports on disease outbreaks. This report describes the design principles, software architecture and implementation of HealthMap and discusses key challenges and future plans. We describe the process by which HealthMap collects and integrates outbreak data from a variety of sources, including news media (e.g., Google News), expert-curated accounts (e.g., ProMED Mail), and validated official alerts. Through the use of text processing algorithms, the system classifies alerts by location and disease and then overlays them on an interactive geographic map. We measure the accuracy of the classification algorithms based on the level of human curation necessary to correct misclassifications, and examine geographic coverage. As part of the evaluation of the system, we analyzed 778 reports with HealthMap, representing 87 disease categories and 89 countries. The automated classifier performed with 84% accuracy, demonstrating significant usefulness in managing the large volume of information processed by the system. Accuracy for ProMED alerts is 91% compared to Google News reports at 81%, as ProMED messages follow a more regular structure. HealthMap is a useful free and open resource employing text-processing algorithms to identify important disease outbreak information through a user-friendly interface.

  10. Fast and robust generation of feature maps for region-based visual attention.

    Science.gov (United States)

    Aziz, Muhammad Zaheer; Mertsching, Bärbel

    2008-05-01

    Visual attention is one of the important phenomena in biological vision which can be followed to achieve more efficiency, intelligence, and robustness in artificial vision systems. This paper investigates a region-based approach that performs pixel clustering prior to the processes of attention in contrast to late clustering as done by contemporary methods. The foundation steps of feature map construction for the region-based attention model are proposed here. The color contrast map is generated based upon the extended findings from the color theory, the symmetry map is constructed using a novel scanning-based method, and a new algorithm is proposed to compute a size contrast map as a formal feature channel. Eccentricity and orientation are computed using the moments of obtained regions and then saliency is evaluated using the rarity criteria. The efficient design of the proposed algorithms allows incorporating five feature channels while maintaining a processing rate of multiple frames per second. Another salient advantage over the existing techniques is the reusability of the salient regions in the high-level machine vision procedures due to preservation of their shapes and precise locations. The results indicate that the proposed model has the potential to efficiently integrate the phenomenon of attention into the main stream of machine vision and systems with restricted computing resources such as mobile robots can benefit from its advantages.

  11. Model Interpretation of Topological Spatial Analysis for the Visually Impaired (Blind Implemented in Google Maps

    Directory of Open Access Journals (Sweden)

    Marcelo Franco Porto

    2013-06-01

    Full Text Available The technological innovations promote the availability of geographic information on the Internet through Web GIS such as Google Earth and Google Maps. These systems contribute to the teaching and diffusion of geographical knowledge that instigates the recognition of the space we live in, leading to the creation of a spatial identity. In these products available on the Web, the interpretation and analysis of spatial information gives priority to one of the human senses: vision. Due to the fact that this representation of information is transmitted visually (image and vectors, a portion of the population is excluded from part of this knowledge because categories of analysis of geographic data such as borders, territory, and space can only be understood by people who can see. This paper deals with the development of a model of interpretation of topological spatial analysis based on the synthesis of voice and sounds that can be used by the visually impaired (blind.The implementation of a prototype in Google Maps and the usability tests performed are also examined. For the development work it was necessary to define the model of topological spatial analysis, focusing on computational implementation, which allows users to interpret the spatial relationships of regions (countries, states and municipalities, recognizing its limits, neighborhoods and extension beyond their own spatial relationships . With this goal in mind, several interface and usability guidelines were drawn up to be used by the visually impaired (blind. We conducted a detailed study of the Google Maps API (Application Programming Interface, which was the environment selected for prototype development, and studied the information available for the users of that system. The prototype was developed based on the synthesis of voice and sounds that implement the proposed model in C # language and in .NET environment. To measure the efficiency and effectiveness of the prototype, usability

  12. Development of the visual system of the chick. II. Mechanisms of axonal guidance.

    Science.gov (United States)

    Thanos, S; Mey, J

    2001-07-01

    The quest to understand axonal guidance mechanisms requires exact and multidisciplinary analyses of axon navigation. This review is the second part of an attempt to synthesise experimental data with theoretical models of the development of the topographic connection of the chick retina with the tectum. The first part included classic ideas from developmental biology and recent achievements on the molecular level in understanding cytodifferentiation and histogenesis [J. Mey, S. Thanos, Development of the visual system of the chick. (I) Cell differentiation and histogenesis, Brain Res. Rev. 32 (2000) 343-379]. The present part deals with the question of how millions of fibres exit from the eye, traverse over several millimetres and spread over the optic tectum to assemble a topographic map, whose precision accounts for the sensory performance of the visual system. The following topics gained special attention in this review. (i) A remarkable conceptual continuity between classic embryology and recent molecular biology has revealed that positional cellular specification precedes and determines the formation of the retinotectal map. (ii) Graded expression of asymmetric genes, transcriptional factors and receptors for signal transduction during early development seem to play a crucial role in determining the spatial identity of neurons within surface areas of retina and optic tectum. (iii) The chemoaffinity hypothesis constitutes the conceptual framework for development of the retinotopic organisation of the primary visual pathway. Studies of repulsive factors in vitro developed the original hypothesis from a theoretical postulate of chemoattraction to an empirically supported concept based on chemorepulsion. (iv) The independent but synchronous development of retina and optic tectum in topo-chronologically corresponding patterns ensures that ingrowing retinal axons encounter receptive target tissue at appropriate locations, and at the time when connections are due to

  13. Unsupervised spatiotemporal analysis of fMRI data using graph-based visualizations of self-organizing maps.

    Science.gov (United States)

    Katwal, Santosh B; Gore, John C; Marois, Rene; Rogers, Baxter P

    2013-09-01

    We present novel graph-based visualizations of self-organizing maps for unsupervised functional magnetic resonance imaging (fMRI) analysis. A self-organizing map is an artificial neural network model that transforms high-dimensional data into a low-dimensional (often a 2-D) map using unsupervised learning. However, a postprocessing scheme is necessary to correctly interpret similarity between neighboring node prototypes (feature vectors) on the output map and delineate clusters and features of interest in the data. In this paper, we used graph-based visualizations to capture fMRI data features based upon 1) the distribution of data across the receptive fields of the prototypes (density-based connectivity); and 2) temporal similarities (correlations) between the prototypes (correlation-based connectivity). We applied this approach to identify task-related brain areas in an fMRI reaction time experiment involving a visuo-manual response task, and we correlated the time-to-peak of the fMRI responses in these areas with reaction time. Visualization of self-organizing maps outperformed independent component analysis and voxelwise univariate linear regression analysis in identifying and classifying relevant brain regions. We conclude that the graph-based visualizations of self-organizing maps help in advanced visualization of cluster boundaries in fMRI data enabling the separation of regions with small differences in the timings of their brain responses.

  14. Geo-Mapping and Visual Stitching to Support Landmine Detection Using a Low-Cost UAV

    Directory of Open Access Journals (Sweden)

    Julian Colorado

    2015-09-01

    Full Text Available This paper describes the development of an aerial system applied for the terrain mapping and geo-detection of explosive landmine-like objects. In practice in Colombia, a large percentage of the anti-personnel mines that still remain across the country are hand-crafted and partially exposed on the terrain's surface so that they can be triggered. This scenario facilitates the use of a vision-based approach for the detection of these artifacts. Our goal is to integrate computer vision algorithms within a low-cost UAV robot suited for the Colombian scenario. The aerial system enables: (i terrain mapping based on a visual stitching method to generate a mosaic image of the covered terrain, and (ii the visual detection of landmine-like objects in real-time. Despite the hardware drawbacks and the camera limitations of the used UAV, we demonstrate that our low-cost platform could be used as a complementary tool for demining missions in Colombia. After briefly reviewing the state of the art regarding the use of robots for mine clearance, we present a field report that confirms the feasibility of our aerial-based system featuring in approximate scenarios.

  15. Visualization maps for the evolution of research hotspots in the field of regional health information networks.

    Science.gov (United States)

    Wang, Yanjun; Zheng, Jianzhong; Zhang, Ailian; Zhou, Wei; Dong, Haiyuan

    2017-04-11

    The aim of this study was to reveal research hotspots in the field of regional health information networks (RHINs) and use visualization techniques to explore their evolution over time and differences between countries. We conducted a literature review for a 50-year period and compared the prevalence of certain index terms during the periods 1963-1993 and 1994-2014 and in six countries. We applied keyword frequency analysis, keyword co-occurrence analysis, multidimensional scaling analysis, and network visualization technology. The total number of keywords was found to increase with time. From 1994 to 2014, the research priorities shifted from hospital planning to community health planning. The number of keywords reflecting information-based research increased. The density of the knowledge network increased significantly, and partial keywords condensed into knowledge groups. All six countries focus on keywords including Information Systems; Telemedicine; Information Service; Medical Records Systems, Computerized; Internet; etc.; however, the level of development and some research priorities are different. RHIN research has generally increased in popularity over the past 50 years. The research hotspots are evolving and are at different levels of development in different countries. Knowledge network mapping and perceptual maps provide useful information for scholars, managers, and policy-makers.

  16. Velocity Mapping Toolbox (VMT): a processing and visualization suite for moving-vessel ADCP measurements

    Science.gov (United States)

    Parsons, D.R.; Jackson, P.R.; Czuba, J.A.; Engel, F.L.; Rhoads, B.L.; Oberg, K.A.; Best, J.L.; Mueller, D.S.; Johnson, K.K.; Riley, J.D.

    2013-01-01

    The use of acoustic Doppler current profilers (ADCP) for discharge measurements and three-dimensional flow mapping has increased rapidly in recent years and has been primarily driven by advances in acoustic technology and signal processing. Recent research has developed a variety of methods for processing data obtained from a range of ADCP deployments and this paper builds on this progress by describing new software for processing and visualizing ADCP data collected along transects in rivers or other bodies of water. The new utility, the Velocity Mapping Toolbox (VMT), allows rapid processing (vector rotation, projection, averaging and smoothing), visualization (planform and cross-section vector and contouring), and analysis of a range of ADCP-derived datasets. The paper documents the data processing routines in the toolbox and presents a set of diverse examples that demonstrate its capabilities. The toolbox is applicable to the analysis of ADCP data collected in a wide range of aquatic environments and is made available as open-source code along with this publication.

  17. Usage of Data-Encoded Web Maps with Client Side Color Rendering for Combined Data Access, Visualization and Modeling Purposes

    Science.gov (United States)

    Pliutau, Denis; Prasad, Narashimha S.

    2013-01-01

    Current approaches to satellite observation data storage and distribution implement separate visualization and data access methodologies which often leads to the need in time consuming data ordering and coding for applications requiring both visual representation as well as data handling and modeling capabilities. We describe an approach we implemented for a data-encoded web map service based on storing numerical data within server map tiles and subsequent client side data manipulation and map color rendering. The approach relies on storing data using the lossless compression Portable Network Graphics (PNG) image data format which is natively supported by web-browsers allowing on-the-fly browser rendering and modification of the map tiles. The method is easy to implement using existing software libraries and has the advantage of easy client side map color modifications, as well as spatial subsetting with physical parameter range filtering. This method is demonstrated for the ASTER-GDEM elevation model and selected MODIS data products and represents an alternative to the currently used storage and data access methods. One additional benefit includes providing multiple levels of averaging due to the need in generating map tiles at varying resolutions for various map magnification levels. We suggest that such merged data and mapping approach may be a viable alternative to existing static storage and data access methods for a wide array of combined simulation, data access and visualization purposes.

  18. From Agents to Continuous Change via Aesthetics: Learning Mechanics with Visual Agentbased Computational Modeling

    CERN Document Server

    Sengupta, Pratim; Wright, Mason

    2013-01-01

    Novice learners find motion as a continuous process of change challenging to understand. In this paper, we present a pedagogical approach based on agent-based, visual programming to address this issue. Integrating Logo programming with curricular science has been shown to be challenging in previous research on educational computing. We present a new Logo-based visual programming language - ViMAP - and, a sequence of learning activities involving programming and modeling, designed specifically to support seamless integration between programming and learning kinematics. We describe relevant affordances of the ViMAP environment that supports such seamless integration. We then present ViMAP-MoMo, a curricular unit designed in ViMAP for modeling kinematics, for a wide range of students (elementary - high school). The main contribution of this paper is that we describe in detail a sequence of learning activities in three phases, discuss the underlying rationale for each phase, and where relevant, report results in ...

  19. Web mapping system for complex processing and visualization of environmental geospatial datasets

    Science.gov (United States)

    Titov, Alexander; Gordov, Evgeny; Okladnikov, Igor

    2016-04-01

    Environmental geospatial datasets (meteorological observations, modeling and reanalysis results, etc.) are used in numerous research applications. Due to a number of objective reasons such as inherent heterogeneity of environmental datasets, big dataset volume, complexity of data models used, syntactic and semantic differences that complicate creation and use of unified terminology, the development of environmental geodata access, processing and visualization services as well as client applications turns out to be quite a sophisticated task. According to general INSPIRE requirements to data visualization geoportal web applications have to provide such standard functionality as data overview, image navigation, scrolling, scaling and graphical overlay, displaying map legends and corresponding metadata information. It should be noted that modern web mapping systems as integrated geoportal applications are developed based on the SOA and might be considered as complexes of interconnected software tools for working with geospatial data. In the report a complex web mapping system including GIS web client and corresponding OGC services for working with geospatial (NetCDF, PostGIS) dataset archive is presented. There are three basic tiers of the GIS web client in it: 1. Tier of geospatial metadata retrieved from central MySQL repository and represented in JSON format 2. Tier of JavaScript objects implementing methods handling: --- NetCDF metadata --- Task XML object for configuring user calculations, input and output formats --- OGC WMS/WFS cartographical services 3. Graphical user interface (GUI) tier representing JavaScript objects realizing web application business logic Metadata tier consists of a number of JSON objects containing technical information describing geospatial datasets (such as spatio-temporal resolution, meteorological parameters, valid processing methods, etc). The middleware tier of JavaScript objects implementing methods for handling geospatial

  20. Personalized Map Symbol Design Mechanism Based on Linguistics

    Directory of Open Access Journals (Sweden)

    LI Wei

    2015-03-01

    Full Text Available The personalization and intelligence of map service ultimately reflects in their symbol design. By establishing conceptual models of personalized map symbols, a theoretical discussion of the symbols is launched from a perspective which both human perceptions and logistic comprehension are considered in this paper, thus to help analyzing the relationship among geographic objects, map symbols and the interpretation of users and exploring the design basis of personalized map symbol. According to some key points such as relevant linguistic theories, the interpretation of the symbol contexts and symbolic statement syntax, design strategies of personalized map symbols is parsed. Thus, methods and processes of personalized map symbol design are proposed accordingly, following by experiments which could verify the hypothesis.

  1. Visualization of Near-Infrared Spectral Data of Eros Using the Small Body Mapping Tool

    Science.gov (United States)

    Klima, Rachel L.; Ernst, Carolyn

    2016-10-01

    One of the primary drivers for many missions visiting asteroids is to advance our understanding of their composition beyond what can be (and is) already measured by telescopes. Without sample return or lander missions, this task relies primarily on resolved near-infrared spectroscopic measurements. Scientific analysis using spectral data collected by point spectrometers is not as straightforward as for imaging spectrometers, where the local spatial context is immediately available. In the case of Eros and other highly non-spherical bodies, this problem becomes even more severe when trying to locate spectra that cross a mapped feature that bends over an irregularly shaped surface. Thus, it is often the case that outside of the mission teams, few from the community at large delve into these data sets, as they lack the tools necessary to incorporate the spectral information into geological analyses of the asteroids. Ultimately, we seek to make such spectral datasets, which NASA has invested significant amounts of money to obtain, more widely accessible and user-friendly. The Small Bodies Mapping Tool (SBMT) is a Java-based, interactive, three-dimensional visualization tool written and developed at APL to map and analyze features on irregularly shaped solar system bodies. The SBMT can be used to locate and then "drape" spacecraft images, spectra, and laser altimetry around the shape model of such bodies. It provides a means for rapid identification of available data in a region of interest and allows features to be mapped directly onto the shape model. The program allows the free rotation of a shape model (including any overlain data) in all directions, so that the correlation and distribution of mapped features can be easily and globally observed.We will present the results of our work on the NEAR/Near-Infrared Spectrograph (NIS) data, including improvements to the calibration made by using the geometric information provided by the SBMT and improvements to the SMBT

  2. MAP_CHANNELS: a computation tool to aid in the visualization and characterization of solvent channels in macromolecular crystals.

    Science.gov (United States)

    Juers, Douglas H; Ruffin, Jon

    2014-12-01

    A computation tool is described that facilitates visualization and characterization of solvent channels or pores within macromolecular crystals. A scalar field mapping the shortest distance to protein surfaces is calculated on a grid covering the unit cell and is written as a map file. The map provides a multiscale representation of the solvent channels, which when viewed in standard macromolecular crystallographic software packages gives an intuitive sense of the solvent channel architecture. The map is analysed to yield descriptors of the topology and the morphology of the solvent channels, including bottleneck radii, tortuosity, width variation and anisotropy.

  3. INTEGRATION ASPECTS OF THE LANGUAGE OF THE MAP IN THE VISUALIZATION OF INFORMATION IN THE INTERNET ERA

    Directory of Open Access Journals (Sweden)

    A. K. Suvorov

    2014-01-01

    Full Text Available Development of new principles of the language maps associated with the use of the Internet, computers and mobile devices. It is shown that the mapping in the modern society with the use of the Internet is based on ready-made visual images of reality, realization of creative opportunities of people by manipulating these images, posting on the Internet of personal information, implementation of project, mapping and other works on the remote services using Web connection. Describes the developed by the author hermeneutic principles of mapping.

  4. Glocalized New Age Spirituality: A Mental Map of the New Central Bus Station in Tel Aviv, Deciphered through Its Visual Codes and Based on Ethno-Visual Research

    Science.gov (United States)

    Ben-Peshat, Malka; Sitton, Shoshana

    2011-01-01

    We present here the findings of an ethno-visual research study involving the creation of a mental map of images, artifacts and practices in Tel Aviv's New Central Bus Station. This huge and complex building, part bus station, part shopping mall, has become a stage for multicultural encounters and interactions among diverse communities of users.…

  5. visualization of reaction mechanism by cg based on quantum

    African Journals Online (AJOL)

    IICBA01

    esterification of acetic acid and ethyl alcohol were visualized by the quantum chemical calculation ... to produce computer graphics (CG) teaching material based on quantum chemical calculations, which provides ..... Weast, R. C., “CRC Handbookof Chemistry and Physics” 63rd ed., CRC Press, Inc, Boca. Raton, Florida ...

  6. Visualization of reaction mechanism by CG based on quantum ...

    African Journals Online (AJOL)

    Visualization by computer graphics is great help for students to have images in the molecular level. In this work, the change in the molecular configuration in fundamental chemical reactions such as, F + HCl ¨ HF + Cl, I + H2¨ HI + H, OH- + CH3Cl ¨ CH3OH + Cl-, and esterification of acetic acid and ethyl alcohol were ...

  7. Neural mechanisms of context-driven conscious visual perception

    NARCIS (Netherlands)

    Klink, P.C.

    2011-01-01

    There is an extensive neural puzzle to be solved between the moment that patterns of light first excite the photoreceptors in our retinas and the moment that we become aware of a visual scene. The effortlessness with which the brain usually solves this puzzle indicates that there must be an

  8. Impact of visual impairment on the lives of young adults in the Netherlands: a concept-mapping approach.

    Science.gov (United States)

    Elsman, Ellen Bernadette Maria; van Rens, Gerardus Hermanus Maria Bartholomeus; van Nispen, Ruth Marie Antoinette

    2017-12-01

    While the impact of visual impairments on specific aspects of young adults' lives is well recognised, a systematic understanding of its impact on all life aspects is lacking. This study aims to provide an overview of life aspects affected by visual impairment in young adults (aged 18-25 years) using a concept-mapping approach. Visually impaired young adults (n = 22) and rehabilitation professionals (n = 16) participated in online concept-mapping workshops (brainstorm procedure), to explore how having a visual impairment influences the lives of young adults. Statements were categorised based on similarity and importance. Using multidimensional scaling, concept maps were produced and interpreted. A total of 59 and 260 statements were generated by young adults and professionals, respectively, resulting in 99 individual statements after checking and deduplication. The combined concept map revealed 11 clusters: work, study, information and regulations, social skills, living independently, computer, social relationships, sport and activities, mobility, leisure time, and hobby. The concept maps provided useful insight into activities influenced by visual impairments in young adults, which can be used by rehabilitation centres to improve their services. This might help in goal setting, rehabilitation referral and successful transition to adult life, ultimately increasing participation and quality of life. Implications for rehabilitation Having a visual impairment affects various life-aspects related to participation, including activities related to work, study, social skills and relationships, activities of daily living, leisure time and mobility. Concept-mapping helped to identify the life aspects affected by low vision, and quantify these aspects in terms of importance according to young adults and low vision rehabilitation professionals. Low vision rehabilitation centres should focus on all life aspects found in this study when identifying the needs of young

  9. Mapping injustice, visualizing equity: why theory, metaphors and images matter in tackling inequalities.

    Science.gov (United States)

    Krieger, N; Dorling, D; McCartney, G

    2012-03-01

    This symposia discussed "Mapping injustice, visualizing equity: why theory, metaphors and images matter in tackling inequalities". It sought to provoke critical thinking about the current theories used to analyze the health impact of injustice, variously referred to as "health inequalities" in the UK, "social inequalities in health" in the US, and "health inequities" more globally. Our focus was the types of explanations, images, and metaphors these theories employ. Building on frameworks that emphasize politics, agency, and accountability, we suggested that it was essential to engage the general public in the politics of health inequities if progress is to be made. We showcased some examples of such engagement before inviting the audience to consider how this might apply in their own areas of responsibility. Copyright © 2012 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  10. Visual interpretation of ASTER satellite data, Part II: Land use mapping in Mpumalanga,South Africa

    Directory of Open Access Journals (Sweden)

    Elna van Niekerk

    2007-09-01

    Full Text Available Since the initiation in 1960 of the era of satellite remote sensing to detect the different characteristics of the earth, a powerful tool was created to aid researchers. Many land-use studies were undertaken using Landsat MSS, Landsat TM and ETM, as well as SPOT satellite data. The application of these data to the mapping of land use and land cover at smaller scales was constrained by the limited spectral and/or spatial resolution of the data provided by these satellite sensors. In view of the relatively high cost of SPOT data, and uncertainty regarding the future continuation of the Landsat series, alternative data sources need to be investigated. In the absence of published previous research on this issue in South Africa, the purpose of this article is to investigate the value of visual interpretation of ASTER satellite images for the identification and mapping of land-use in an area in South Africa. The study area is situated in Mpumalanga, in the area of Witbank, around the Witbank and Doorndraai dams. This area is characterised by a variety of urban, rural and industrial land uses. Digital image processing of one Landsat 5 TM, one Landsat 7 ETM and one ASTER satellite image was undertaken, including atmospheric correction and georeferencing, natural colour composites, photo infrared colour composites (or false colour satellite images, band ratios, Normalised Difference Indices, as well as the Brightness, Greenness and Wetness Indices. The efficacy with which land use could be identified through the visual interpretation of the processed Landsat 5 TM, Landsat 7 TM and ASTER satellite images was compared. The published 1:50 000 topographical maps of the area were used for the purpose of initial verification. Findings of the visual interpretation process were verified by field visits to the study area. The study found that the ASTER satellite data produced clearer results and therefore have a higher mapping ability and capacity than the

  11. Visualization in Mechanics: The Dynamics of an Unbalanced Roller

    Science.gov (United States)

    Cumber, Peter S.

    2017-01-01

    It is well known that mechanical engineering students often find mechanics a difficult area to grasp. This article describes a system of equations describing the motion of a balanced and an unbalanced roller constrained by a pivot arm. A wide range of dynamics can be simulated with the model. The equations of motion are embedded in a graphical…

  12. Visualizing the spatiotemporal map of Rac activation in bovine aortic endothelial cells under laminar and disturbed flows.

    Directory of Open Access Journals (Sweden)

    Shuai Shao

    Full Text Available Disturbed flow can eliminate the alignment of endothelial cells in the direction of laminar flow, and significantly impacts on atherosclerosis in collateral arteries near the bifurcation and high curvature regions. While shear stress induced Rac polarity has been shown to play crucial roles in cell polarity and migration, little is known about the spatiotemporal map of Rac under disturbed flow, and the mechanism of flow-induced cell polarity still needs to be elucidated. In this paper, disturbed flow or laminar flow with 15 dyn/cm2 of average shear stress was applied on bovine aortic endothelial cells (BAECs for 30 minutes. A genetically-encoded PAK-PBD-GFP reporter was transfected into BAECs to visualize the real-time activation of Rac in living cell under fluorescence microscope. The imaging of the fluorescence intensity was analyzed by Matlab and the normalized data was converted into 3D spatiotemporal map. Then the changes of data upon chemical interference were fitted with logistic curve to explore the rule and mechanism of Rac polarity under laminar or disturbed flow. A polarized Rac activation was observed at the downstream edge along the laminar flow, which was enhanced by benzol alcohol-enhanced membrane fluidity but inhibited by nocodazole-disrupted microtubules or cholesterol-inhibited membrane fluidity, while no obvious polarized Rac activation could be found upon disturbed flow application. It is concluded that disturbed flow inhibits the flow-induced Rac polarized activation, which is related to the interaction of cell membrane and cytoskeleton, especially the microtubules.

  13. Web Maps and Services at NOAA for Bathymetric Data Discovery, Visualization, and Access

    Science.gov (United States)

    Varner, J. D.; Cartwright, J.

    2016-12-01

    NOAA's National Centers for Environmental Information (NCEI) ensures the security and widespread availability of marine geophysical data through long-term stewardship. NCEI stewards bathymetric data and products from numerous sources, including near-shore hydrographic survey data from NOAA's National Ocean Service, deep-water multibeam and single-beam echosounder data collected by U.S. and non-U.S. institutions, as well as digital elevation models (DEMs) that integrate ocean bathymetry and land topography. These data can be discovered, visualized, and accessed via a suite of ArcGIS web services and by using a web map which integrates these component services: the Bathymetric Data Viewer. The services provide data coverage (e.g. survey tracklines, DEM footprints), color shaded relief visualizations of bathymetry, and seamless mosaics of elevation data. These services are usable in web applications (both within and outside NOAA), and in desktop GIS software. Users can utilize the Bathymetric Data Viewer to narrow down data of interest, identify datasets, then submit an order to NCEI's extract system for data retrieval.

  14. Visual data mining with self-organising maps for ventricular fibrillation analysis.

    Science.gov (United States)

    Rosado-Muñoz, Alfredo; Martínez-Martínez, José M; Escandell-Montero, Pablo; Soria-Olivas, Emilio

    2013-08-01

    Detection of ventricular fibrillation (VF) at an early stage is being deeply studied in order to lower the risk of sudden death and allows the specialist to have greater reaction time to give the patient a good recovering therapy. Some works are focusing on detecting VF based on numerical analysis of time-frequency distributions, but in general the methods used do not provide insight into the problem. However, this study proposes a new methodology in order to obtain information about this problem. This work uses a supervised self-organising map (SOM) to obtain visually information among four important groups of patients: VF (ventricular fibrillation), VT (ventricular tachycardia), HP (healthy patients) and AHR (other anomalous heart rates and noise). A total number of 27 variables were obtained from continuous surface ECG recordings in standard databases (MIT and AHA), providing information in the time, frequency, and time-frequency domains. self-organising maps (SOMs), trained with 11 of the 27 variables, were used to extract knowledge about the variable values for each group of patients. Results show that the SOM technique allows to determine the profile of each group of patients, assisting in gaining a deeper understanding of this clinical problem. Additionally, information about the most relevant variables is given by the SOM analysis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  15. Constructivist-Visual Mind Map Teaching Approach and the Quality of Students' Cognitive Structures

    Science.gov (United States)

    Dhindsa, Harkirat S.; Makarimi-Kasim; Roger Anderson, O.

    2011-04-01

    This study compared the effects of a constructivist-visual mind map teaching approach (CMA) and of a traditional teaching approach (TTA) on (a) the quality and richness of students' knowledge structures and (b) TTA and CMA students' perceptions of the extent that a constructivist learning environment (CLE) was created in their classes. The sample of the study consisted of six classes (140 Form 3 students of 13-15 years old) selected from a typical coeducational school in Brunei. Three classes (40 boys and 30 girls) were taught using the TTA while three other classes (41 boys and 29 girls) used the CMA, enriched with PowerPoint presentations. After the interventions (lessons on magnetism), the students in both groups were asked to describe in writing their understanding of magnetism accrued from the lessons. Their written descriptions were analyzed using flow map analyses to assess their content knowledge and its organisation in memory as evidence of cognitive structure. The extent of CLE was measured using a published CLE survey. The results showed that the cognitive structures of the CMA students were more extensive, thematically organised and richer in interconnectedness of thoughts than those of TTA students. Moreover, CMA students also perceived their classroom learning environment to be more constructivist than their counterparts. It is, therefore, recommended that teachers consider using the CMA teaching technique to help students enrich their understanding, especially for more complex or abstract scientific content.

  16. Neuroanatomical Dissections of Unilateral Visual Neglect Symptoms: ALE Meta-Analysis of Lesion-Symptom Mapping

    Science.gov (United States)

    Chechlacz, Magdalena; Rotshtein, Pia; Humphreys, Glyn W.

    2012-01-01

    Unilateral visual neglect is commonly defined as impaired ability to attend to stimuli presented on the side of visual space contralateral to the brain lesion. However, behavioral analyses indicate that different neglect symptoms can dissociate. The neuroanatomy of the syndrome has been hotly debated. Some groups have argued that the syndrome is linked to posterior parietal cortex lesions, while others report damage within regions including the superior temporal gyrus, insula, and basal ganglia. Several recent neuroimaging studies provide evidence that heterogeneity in the behavioral symptoms of neglect can be matched by variations in the brain lesions, and that some of the discrepancies across earlier findings might have resulted from the use of different neuropsychological tests and/or varied measures within the same task for diagnosing neglect. In this paper, we review the evidence for dissociations between both the symptoms and the neural substrates of unilateral visual neglect, drawing on ALE (anatomic likelihood estimation) meta-analyses of lesion-symptom mapping studies. Specifically, we examine dissociations between neglect symptoms associated with impaired control of attention across space (in an egocentric frame of reference) and within objects (in an allocentric frame of reference). Results of ALE meta-analyses indicated that, while egocentric symptoms are associated with damage within perisylvian network (pre- and postcentral, supramarginal, and superior temporal gyri) and damage within sub-cortical structures, more posterior lesions including the angular, middle temporal, and middle occipital gyri are associated with allocentric symptoms. Furthermore, there was high concurrence in deficits associated with white matter lesions within long association (superior longitudinal, inferior fronto-occipital, and inferior longitudinal fasciculi) and projection (corona radiata and thalamic radiation) pathways, supporting a disconnection account of the syndrome

  17. Visualization Beyond the Map: The Challenges of Managing Data for Re-Use

    Science.gov (United States)

    Allison, M. D.; Groman, R. C.; Chandler, C. L.; Galvarino, C. R.; Wiebe, P. H.; Glover, D. M.

    2012-12-01

    The Biological and Chemical Oceanography Data Management Office (BCO-DMO) makes data publicly accessible via both a text-based and a geospatial interface, the latter using the Open Geospatial Consortium (OGC) compliant open-source MapServer software originally from the University of Minnesota. Making data available for reuse by the widest variety of users is one of the overriding goals of BCO-DMO and one of our greatest challenges. The biogeochemical, ecological and physical data we manage are extremely heterogeneous. Although it is not possible to be all things to all people, we are actively working on ways to make the data re-usable by the most people. Looking at data in a different way is one of the underpinnings of data re-use and the easier we can make data accessible, the more the community of users will benefit. We can help the user determine usefulness by providing some specific tools. Sufficiently well-informed metadata can often be enough to determine fitness for purpose, but many times our geospatial interface to the data and metadata is more compelling. Displaying the data visually in as many ways as possible enables the scientist, teacher or manager to decide if the data are useful and then being able to download the data right away with no login required is very attractive. We will present ways of visualizing different kinds of data and discuss using metadata to drive the visualization tools. We will also discuss our attempts to work with data providers to organize their data in ways to make them reusable to the largest audience and to solicit input from data users about the effectiveness of our solutions.

  18. Airport object extraction based on visual attention mechanism and parallel line detection

    Science.gov (United States)

    Lv, Jing; Lv, Wen; Zhang, Libao

    2017-10-01

    Target extraction is one of the important aspects in remote sensing image analysis and processing, which has wide applications in images compression, target tracking, target recognition and change detection. Among different targets, airport has attracted more and more attention due to its significance in military and civilian. In this paper, we propose a novel and reliable airport object extraction model combining visual attention mechanism and parallel line detection algorithm. First, a novel saliency analysis model for remote sensing images with airport region is proposed to complete statistical saliency feature analysis. The proposed model can precisely extract the most salient region and preferably suppress the background interference. Then, the prior geometric knowledge is analyzed and airport runways contained two parallel lines with similar length are detected efficiently. Finally, we use the improved Otsu threshold segmentation method to segment and extract the airport regions from the salient map of remote sensing images. The experimental results demonstrate that the proposed model outperforms existing saliency analysis models and shows good performance in the detection of the airport.

  19. Neural mechanisms underlying sound-induced visual motion perception: An fMRI study.

    Science.gov (United States)

    Hidaka, Souta; Higuchi, Satomi; Teramoto, Wataru; Sugita, Yoichi

    2017-07-01

    Studies of crossmodal interactions in motion perception have reported activation in several brain areas, including those related to motion processing and/or sensory association, in response to multimodal (e.g., visual and auditory) stimuli that were both in motion. Recent studies have demonstrated that sounds can trigger illusory visual apparent motion to static visual stimuli (sound-induced visual motion: SIVM): A visual stimulus blinking at a fixed location is perceived to be moving laterally when an alternating left-right sound is also present. Here, we investigated brain activity related to the perception of SIVM using a 7T functional magnetic resonance imaging technique. Specifically, we focused on the patterns of neural activities in SIVM and visually induced visual apparent motion (VIVM). We observed shared activations in the middle occipital area (V5/hMT), which is thought to be involved in visual motion processing, for SIVM and VIVM. Moreover, as compared to VIVM, SIVM resulted in greater activation in the superior temporal area and dominant functional connectivity between the V5/hMT area and the areas related to auditory and crossmodal motion processing. These findings indicate that similar but partially different neural mechanisms could be involved in auditory-induced and visually-induced motion perception, and neural signals in auditory, visual, and, crossmodal motion processing areas closely and directly interact in the perception of SIVM. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Self-Organizing Neural Network Map for the Purpose of Visualizing the Concept Images of Students on Angles

    Science.gov (United States)

    Kaya, Deniz

    2017-01-01

    The purpose of the study is to perform a less-dimensional thorough visualization process for the purpose of determining the images of the students on the concept of angle. The Ward clustering analysis combined with Self-Organizing Neural Network Map (SOM) has been used for the dimension process. The Conceptual Understanding Tool, which consisted…

  1. Rapid mapping of compound eye visual sampling parameters with FACETS, a highly automated wide-field goniometer.

    Science.gov (United States)

    Douglass, John K; Wehling, Martin F

    2016-12-01

    A highly automated goniometer instrument (called FACETS) has been developed to facilitate rapid mapping of compound eye parameters for investigating regional visual field specializations. The instrument demonstrates the feasibility of analyzing the complete field of view of an insect eye in a fraction of the time required if using non-motorized, non-computerized methods. Faster eye mapping makes it practical for the first time to employ sample sizes appropriate for testing hypotheses about the visual significance of interspecific differences in regional specializations. Example maps of facet sizes are presented from four dipteran insects representing the Asilidae, Calliphoridae, and Stratiomyidae. These maps provide the first quantitative documentation of the frontal enlarged-facet zones (EFZs) that typify asilid eyes, which, together with the EFZs in male Calliphoridae, are likely to be correlated with high-spatial-resolution acute zones. The presence of EFZs contrasts sharply with the almost homogeneous distribution of facet sizes in the stratiomyid. Moreover, the shapes of EFZs differ among species, suggesting functional specializations that may reflect differences in visual ecology. Surveys of this nature can help identify species that should be targeted for additional studies, which will elucidate fundamental principles and constraints that govern visual field specializations and their evolution.

  2. Feature-expression heat maps - A new visual method to explore complex associations between two variable sets

    NARCIS (Netherlands)

    Haarman, Bartholomeus C. M. (Benno); Riemersma-Van der Lek, Rixt F.; Nolen, Willem A.; Mendes, R.; Drexhage, Hemmo A.; Burger, Huibert

    Introduction: Existing methods such as correlation plots and cluster heat maps are insufficient in the visual exploration of multiple associations between genetics and phenotype, which is of importance to achieve a better understanding of the pathophysiology of psychiatric and other illnesses. The

  3. Circuits and Mechanisms for Surround Modulation in Visual Cortex.

    Science.gov (United States)

    Angelucci, Alessandra; Bijanzadeh, Maryam; Nurminen, Lauri; Federer, Frederick; Merlin, Sam; Bressloff, Paul C

    2017-07-25

    Surround modulation (SM) is a fundamental property of sensory neurons in many species and sensory modalities. SM is the ability of stimuli in the surround of a neuron's receptive field (RF) to modulate (typically suppress) the neuron's response to stimuli simultaneously presented inside the RF, a property thought to underlie optimal coding of sensory information and important perceptual functions. Understanding the circuit and mechanisms for SM can reveal fundamental principles of computations in sensory cortices, from mouse to human. Current debate is centered over whether feedforward or intracortical circuits generate SM, and whether this results from increased inhibition or reduced excitation. Here we present a working hypothesis, based on theoretical and experimental evidence, that SM results from feedforward, horizontal, and feedback interactions with local recurrent connections, via synaptic mechanisms involving both increased inhibition and reduced recurrent excitation. In particular, strong and balanced recurrent excitatory and inhibitory circuits play a crucial role in the computation of SM.

  4. Helical Nanomachines for Fast Mechanical Mapping of Heterogeneous Environments

    CERN Document Server

    Ghosh, Arijit

    2016-01-01

    Artificial micro and nano machines have been envisioned and demonstrated as potential candidates for variety of applications, ranging from targeted drug or gene delivery, cell manipulation, environmental sensing and many more. Here, we demonstrate the application of helical nanomachines that can measure and map the local rheological properties of a complex heterogeneous environment. The position of the helical nanomachine was controlled precisely using magnetic fields, while the instantaneous orientation provided an estimation of the viscosity of the surrounding medium with high spatial and temporal accuracy. Apart from providing viscosity estimates in purely viscous and viscoelastic media with shear rate independent viscosity (Boger fluids), their motion was also found to be extremely sensitive to fluid elasticity. Taken together we report a promising new technique of mapping the rheological properties of a complex fluidic environment by helical nanomachines with high spatial and temporal resolutions, a func...

  5. Mapping and Visualization of Storm-Surge Dynamics for Hurricane Katrina and Hurricane Rita

    Science.gov (United States)

    Gesch, Dean B.

    2009-01-01

    The damages caused by the storm surges from Hurricane Katrina and Hurricane Rita were significant and occurred over broad areas. Storm-surge maps are among the most useful geospatial datasets for hurricane recovery, impact assessments, and mitigation planning for future storms. Surveyed high-water marks were used to generate a maximum storm-surge surface for Hurricane Katrina extending from eastern Louisiana to Mobile Bay, Alabama. The interpolated surface was intersected with high-resolution lidar elevation data covering the study area to produce a highly detailed digital storm-surge inundation map. The storm-surge dataset and related data are available for display and query in a Web-based viewer application. A unique water-level dataset from a network of portable pressure sensors deployed in the days just prior to Hurricane Rita's landfall captured the hurricane's storm surge. The recorded sensor data provided water-level measurements with a very high temporal resolution at surveyed point locations. The resulting dataset was used to generate a time series of storm-surge surfaces that documents the surge dynamics in a new, spatially explicit way. The temporal information contained in the multiple storm-surge surfaces can be visualized in a number of ways to portray how the surge interacted with and was affected by land surface features. Spatially explicit storm-surge products can be useful for a variety of hurricane impact assessments, especially studies of wetland and land changes where knowledge of the extent and magnitude of storm-surge flooding is critical.

  6. Use of Concept Maps as an Assessment Tool in Mechanical Engineering Education

    Science.gov (United States)

    Tembe, B. L.; Kamble, S. K.

    2013-01-01

    The purpose of this study to investigate, how third year mechanical engineering students are able to use their knowledge of concept maps in their study of the topic of "Introduction to the Internal Combustion Engines (IICE)". 41 students participated in this study. Firstly, the students were taught about concept maps and then asked to…

  7. An electrophysiological insight into visual attention mechanisms underlying schizotypy.

    Science.gov (United States)

    Fuggetta, Giorgio; Bennett, Matthew A; Duke, Philip A

    2015-07-01

    A theoretical framework has been put forward to understand attention deficits in schizophrenia (Luck SJ & Gold JM. Biological Psychiatry. 2008; 64:34-39). We adopted this framework to evaluate any deficits in attentional processes in schizotypy. Sixteen low schizotypal (LoS) and 16 high schizotypal (HiS) individuals performed a novel paradigm combining a match-to-sample task, with inhibition of return (using spatially uninformative cues) and memory-guided efficient visual-search within one trial sequence. Behavioural measures and event-related potentials (ERPs) were recorded. Behaviourally, HiS individuals exhibited a spatial cueing effect while LoS individuals showed the more typical inhibition of return effect. These results suggest HiS individuals have a relative deficit in rule selection - the endogenous control process involved in disengaging attention from the uninformative location cue. ERP results showed that the late-phase of N2pc evoked by the target stimulus had greater peak latency and amplitude in HiS individuals. This suggests a relative deficit in the implementation of selection - the process of focusing attention onto target features that enhances relevant/suppresses irrelevant inputs. This is a different conclusion than when the same theoretical framework has been applied to schizophrenia, which argues little or no deficit in implementation of selection amongst patients. Also, HiS individuals exhibited earlier onset and greater amplitude of the mismatch-triggered negativity component. In summary, our results indicate deficits of both control and implementation of selection in HiS individuals. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Interlayer Repulsion of Retinal Ganglion Cell Mosaics Regulates Spatial Organization of Functional Maps in the Visual Cortex.

    Science.gov (United States)

    Jang, Jaeson; Paik, Se-Bum

    2017-12-13

    In higher mammals, orientation tuning of neurons is organized into a quasi-periodic pattern in the primary visual cortex. Our previous model studies suggested that the topography of cortical orientation maps may originate from moiré interference of ON and OFF retinal ganglion cell (RGC) mosaics, but did not account for how the consistent spatial period of maps could be achieved. Here we address this issue with two crucial findings on the development of RGC mosaics: first, homotypic local repulsion between RGCs can develop a long-range hexagonal periodicity. Second, heterotypic interaction restrains the alignment of ON and OFF mosaics, and generates a periodic interference pattern map with consistent spatial frequency. To validate our model, we quantitatively analyzed the RGC mosaics in cat data, and confirmed that the observed retinal mosaics showed evidence of heterotypic interactions, contrary to the previous view that ON and OFF mosaics are developed independently.SIGNIFICANCE STATEMENT Orientation map is one of the most studied functional maps in the brain, but it has remained unanswered how the consistent spatial periodicity of maps could be developed. In the current study, we address this issue with our developmental model for the retinal origin of orientation map. We showed that local repulsive interactions between retinal ganglion cells (RGCs) can develop a hexagonal periodicity in the RGC mosaics and restrict the alignment between ON and OFF mosaics, so that they generate a periodic pattern with consistent spatial frequency for both the RGC mosaics and the cortical orientation maps. Our results demonstrate that the organization of functional maps in visual cortex, including its structural consistency, may be constrained by a retinal blueprint. Copyright © 2017 the authors 0270-6474/17/3712141-12$15.00/0.

  9. Integrating Spherical Panoramas and Maps for Visualization of Cultural Heritage Objects Using Virtual Reality Technology.

    Science.gov (United States)

    Koeva, Mila; Luleva, Mila; Maldjanski, Plamen

    2017-04-11

    Development and virtual representation of 3D models of Cultural Heritage (CH) objects has triggered great interest over the past decade. The main reason for this is the rapid development in the fields of photogrammetry and remote sensing, laser scanning, and computer vision. The advantages of using 3D models for restoration, preservation, and documentation of valuable historical and architectural objects have been numerously demonstrated by scientists in the field. Moreover, 3D model visualization in virtual reality has been recognized as an efficient, fast, and easy way of representing a variety of objects worldwide for present-day users, who have stringent requirements and high expectations. However, the main focus of recent research is the visual, geometric, and textural characteristics of a single concrete object, while integration of large numbers of models with additional information-such as historical overview, detailed description, and location-are missing. Such integrated information can be beneficial, not only for tourism but also for accurate documentation. For that reason, we demonstrate in this paper an integration of high-resolution spherical panoramas, a variety of maps, GNSS, sound, video, and text information for representation of numerous cultural heritage objects. These are then displayed in a web-based portal with an intuitive interface. The users have the opportunity to choose freely from the provided information, and decide for themselves what is interesting to visit. Based on the created web application, we provide suggestions and guidelines for similar studies. We selected objects, which are located in Bulgaria-a country with thousands of years of history and cultural heritage dating back to ancient civilizations. The methods used in this research are applicable for any type of spherical or cylindrical images and can be easily followed and applied in various domains. After a visual and metric assessment of the panoramas and the evaluation of

  10. Social Identity Mapping: A procedure for visual representation and assessment of subjective multiple group memberships.

    Science.gov (United States)

    Cruwys, Tegan; Steffens, Niklas K; Haslam, S Alexander; Haslam, Catherine; Jetten, Jolanda; Dingle, Genevieve A

    2016-12-01

    In this research, we introduce Social Identity Mapping (SIM) as a method for visually representing and assessing a person's subjective network of group memberships. To provide evidence of its utility, we report validating data from three studies (two longitudinal), involving student, community, and clinical samples, together comprising over 400 participants. Results indicate that SIM is easy to use, internally consistent, with good convergent and discriminant validity. Each study also illustrates the ways that SIM can be used to address a range of novel research questions. Study 1 shows that multiple positive group memberships are a particularly powerful predictor of well-being. Study 2 shows that social support is primarily given and received within social groups and that only in-group support is beneficial for well-being. Study 3 shows that improved mental health following a social group intervention is attributable to an increase in group compatibility. In this way, the studies demonstrate the capacity for SIM to make a contribution both to the development of social-psychological theory and to its practical application. © 2016 The British Psychological Society.

  11. Modeling eye movements in visual agnosia with a saliency map approach: bottom-up guidance or top-down strategy?

    Science.gov (United States)

    Foulsham, Tom; Barton, Jason J S; Kingstone, Alan; Dewhurst, Richard; Underwood, Geoffrey

    2011-08-01

    Two recent papers (Foulsham, Barton, Kingstone, Dewhurst, & Underwood, 2009; Mannan, Kennard, & Husain, 2009) report that neuropsychological patients with a profound object recognition problem (visual agnosic subjects) show differences from healthy observers in the way their eye movements are controlled when looking at images. The interpretation of these papers is that eye movements can be modeled as the selection of points on a saliency map, and that agnosic subjects show an increased reliance on visual saliency, i.e., brightness and contrast in low-level stimulus features. Here we review this approach and present new data from our own experiments with an agnosic patient that quantifies the relationship between saliency and fixation location. In addition, we consider whether the perceptual difficulties of individual patients might be modeled by selectively weighting the different features involved in a saliency map. Our data indicate that saliency is not always a good predictor of fixation in agnosia: even for our agnosic subject, as for normal observers, the saliency-fixation relationship varied as a function of the task. This means that top-down processes still have a significant effect on the earliest stages of scanning in the setting of visual agnosia, indicating severe limitations for the saliency map model. Top-down, active strategies-which are the hallmark of our human visual system-play a vital role in eye movement control, whether we know what we are looking at or not. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Cortical and white matter mapping in the visual system- more than meets theeye: on the importance of functional imaging to understand visual systempathologies

    Directory of Open Access Journals (Sweden)

    Noa eRaz

    2014-08-01

    Full Text Available Information transmission within the visual system is highly organized with the ultimate goal of accomplishing higher-order, complex visuo-spatial and object identity processing. Perception is dependent on the intactness of the entire system and damage at each stage – in the eye itself, the visual pathways, or within cortical processing - might result in perception disturbance.Herein we will review several examples of lesions along the visual system, from the retina, via the optic nerve and chiasm and through the occipital cortex. We will address their clinical manifestation and their cortical substrate. The latter will be studied via functional magnetic resonance imaging (fMRI and Diffusion Tensor Imaging (DTI, enabling cortical and white matter mapping of the human brain. In contrast to traditional signal recording, these procedures enable simultaneous evaluation of the entire brain network engaged when subjects undertake a particular task or evaluate the entirety of associated white matter pathways.These examples provided will highlight the importance of using advanced imaging methods to better understand visual pathologies. We will argue that clinical manifestation cannot always be explained solely by structural damage and a functional view is required to understand the clinical symptom. In such cases we recommend using advanced imaging methods to better understand the neurological basis of visual phenomena.

  13. Visualizing spatio-temporal war casualty data in Google Earth - A case study of Map the Fallen (Invited)

    Science.gov (United States)

    Askay, S.

    2009-12-01

    Published on Memorial Day 2009, Map the Fallen is a Google Earth visualization of the 5500+ US and international soldiers that have died in Iraq and Afghanistan since 2001. In addition to providing photos, stories and links for each solider, the time-animated map visually connects hometowns to places of death. This novel way of representing casualty data brings the geographic reach and magnitude of the issue into focus together with the very personal nature of individual stories. Innovative visualizations techniques were used that illustrate the spatio-temporal nature of this information and to show the global reach and interconnectivity of this issue. Several of advanced KML techniques employed to create this engaging and performance-conscious map will be discussed during this session. These include: 1) the use of HTML iframes and javascript to minimize the KML size, and extensive cross-linking throughout content; 2) the creation of a time-animated, on-screen casualty counter; 3) the use of parabolic arcs to connect each hometown to place of death; 4) the use of concentric spirals to represent chronological data; and 5) numerous performance optimizations to ensure the 23K placemarks, 2500 screen overlays and nearly 250k line vertices performed well in Google Earth. This session will include a demonstration of the map, conceptual discussions of the techniques used, and some in-depth technical explanation of the KML code.

  14. COMPARING IMAGE-BASED METHODS FOR ASSESSING VISUAL CLUTTER IN GENERALIZED MAPS

    Directory of Open Access Journals (Sweden)

    G. Touya

    2015-08-01

    Full Text Available Map generalization abstracts and simplifies geographic information to derive maps at smaller scales. The automation of map generalization requires techniques to evaluate the global quality of a generalized map. The quality and legibility of a generalized map is related to the complexity of the map, or the amount of clutter in the map, i.e. the excessive amount of information and its disorganization. Computer vision research is highly interested in measuring clutter in images, and this paper proposes to compare some of the existing techniques from computer vision, applied to generalized maps evaluation. Four techniques from the literature are described and tested on a large set of maps, generalized at different scales: edge density, subband entropy, quad tree complexity, and segmentation clutter. The results are analyzed against several criteria related to generalized maps, the identification of cluttered areas, the preservation of the global amount of information, the handling of occlusions and overlaps, foreground vs background, and blank space reduction.

  15. Visualizing vowel-production mechanism using simple educational tools

    Science.gov (United States)

    Arai, Takayuki

    2005-09-01

    To develop intuitive and effective methods for educating Acoustics to students of different ages and from varied backgrounds, Arai [J. Phonetic Soc. Jpn. 5, 31-38, (2001)] replicated Chiba and Kajiyama's physical models of the human vocal tract as educational tools and verified that the physical models and sound sources, such as an artificial larynx, yield a simple but powerful demonstration of vowel production in the classroom. We have also started exhibiting our models at the Science Museum ``Ru-Ku-Ru'' in Shizuoka City, Japan. We further extended our model to a lung model as well as several head-shaped models with visible vocal tract to demonstrate the total vowel-production mechanism from phonation to articulation. The lung model imitates the human respiratory system with a diaphragm. In the head-shaped model, the midsaggital cross section is visible from the outside. To adjust the degree of nasopharyngeal coupling, the velum may be rotated. Another head-shaped model with the manipulable tongue position was also developed. Two test results were compared before and after using these physical models, and the educational effectiveness of the models was confirmed. The homepage of the vocal-tract models is available at http://www.splab.ee.sophia.ac.jp/Vocal-Tract-Model/index-e.htm. [Work supported by KAKENHI (17500603).

  16. Compressive deformation and yielding mechanisms in cellular Al alloys determined using X-ray tomography and surface strain mapping

    Energy Technology Data Exchange (ETDEWEB)

    Bart-Smith, H.; Bastawros, A.F.; Mumm, D.R.; Evans, A.G. [Harvard Univ., Cambridge, MA (United States). Div. of Engineering and Applied Sciences; Sypeck, D.J.; Wadley, H.N.G. [Univ. of Virginia, Charlottesville, VA (United States). School of Engineering and Applied Science

    1998-12-31

    The mechanisms of compressive deformation that occur in closed cell Al alloys have been established. This has been achieved by using x-ray computed tomography (CT) and surface strain mapping to determine the deformation modes and the cell morphologies that control the onset of yielding. The deformation is found to localize in narrow bands having width of order of a cell diameter. Outside the bands, the material remains elastic. The cells within the bands that experience large permanent strains are primarily elliptical. A group of cells work collectively to allow large localized deformation. Size does not appear to be the initiator of the deformation bands. Equiaxed cells remain elastic. The implications for manufacturing materials with superior mechanical properties are discussed. Visualization of internal deformation of a closed cell Al alloy core, as part of a sandwich panel construction, is also possible using x-ray tomography. Preliminary results for a punch indentation test are presented.

  17. Mapping Nondominant Voices into Understanding Stress-Coping Mechanisms

    Science.gov (United States)

    Iwasaki, Yoshitaka; Bartlett, Judith; MacKay, Kelly; Mactavish, Jennifer; Ristock, Janice

    2008-01-01

    This study reports key findings from a research project, which examined the stress and coping mechanisms of several nondominant groups of individuals. The groups were based in Winnipeg, Manitoba, Canada and included (a) Aboriginal individuals with diabetes, (b) individuals with disabilities, and (c) gays and lesbians. Our analyses of personal…

  18. Mapping brain activation and information during category-specific visual working memory

    National Research Council Canada - National Science Library

    Linden, David E J; Oosterhof, Nikolaas N; Klein, Christoph; Downing, Paul E

    2012-01-01

    How is working memory for different visual categories supported in the brain? Do the same principles of cortical specialization that govern the initial processing and encoding of visual stimuli also apply to their short-term maintenance...

  19. Interactions of top-down and bottom-up mechanisms in human visual cortex.

    Science.gov (United States)

    McMains, Stephanie; Kastner, Sabine

    2011-01-12

    Multiple stimuli present in the visual field at the same time compete for neural representation by mutually suppressing their evoked activity throughout visual cortex, providing a neural correlate for the limited processing capacity of the visual system. Competitive interactions among stimuli can be counteracted by top-down, goal-directed mechanisms such as attention, and by bottom-up, stimulus-driven mechanisms. Because these two processes cooperate in everyday life to bias processing toward behaviorally relevant or particularly salient stimuli, it has proven difficult to study interactions between top-down and bottom-up mechanisms. Here, we used an experimental paradigm in which we first isolated the effects of a bottom-up influence on neural competition by parametrically varying the degree of perceptual grouping in displays that were not attended. Second, we probed the effects of directed attention on the competitive interactions induced with the parametric design. We found that the amount of attentional modulation varied linearly with the degree of competition left unresolved by bottom-up processes, such that attentional modulation was greatest when neural competition was little influenced by bottom-up mechanisms and smallest when competition was strongly influenced by bottom-up mechanisms. These findings suggest that the strength of attentional modulation in the visual system is constrained by the degree to which competitive interactions have been resolved by bottom-up processes related to the segmentation of scenes into candidate objects.

  20. Keep your eyes on development - The behavioural and neurophysiological development of visual mechanisms underlying form processing

    Directory of Open Access Journals (Sweden)

    Carlijn eVan Den Boomen

    2012-03-01

    Full Text Available Visual form perception is essential for correct interpretation of, and interaction with, our environment. Form perception depends on visual acuity and processing of specific form characteristics, such as luminance contrast, spatial frequency, colour, orientation, depth and even motion information. As other cognitive processes, form perception matures with age. This paper aims at providing a concise overview of our current understanding of the typical development, from birth to adulthood, of form-characteristic processing, as measured both behaviourally and neurophysiologically. Two main conclusions can be drawn. First, the current literature conveys that for most reviewed characteristics a developmental pattern is apparent. These trajectories are discussed in relation to the organisation of the visual system. The second conclusion is that significant gaps in the literature exist for several age-ranges. To complete our understanding of the typical and, by consequence, atypical development of visual mechanisms underlying form processing, future research should uncover these missing segments.

  1. Combined visualization for noise mapping of industrial facilities based on ray-tracing and thin plate splines

    Science.gov (United States)

    Ovsiannikov, Mikhail; Ovsiannikov, Sergei

    2017-01-01

    The paper presents the combined approach to noise mapping and visualizing of industrial facilities sound pollution using forward ray tracing method and thin-plate spline interpolation. It is suggested to cauterize industrial area in separate zones with similar sound levels. Equivalent local source is defined for range computation of sanitary zones based on ray tracing algorithm. Computation of sound pressure levels within clustered zones are based on two-dimension spline interpolation of measured data on perimeter and inside the zone.

  2. Image Mapping and Visual Attention on the Sensory Ego-Sphere

    Science.gov (United States)

    Fleming, Katherine Achim; Peters, Richard Alan, II

    2012-01-01

    The Sensory Ego-Sphere (SES) is a short-term memory for a robot in the form of an egocentric, tessellated, spherical, sensory-motor map of the robot s locale. Visual attention enables fast alignment of overlapping images without warping or position optimization, since an attentional point (AP) on the composite typically corresponds to one on each of the collocated regions in the images. Such alignment speeds analysis of the multiple images of the area. Compositing and attention were performed two ways and compared: (1) APs were computed directly on the composite and not on the full-resolution images until the time of retrieval; and (2) the attentional operator was applied to all incoming imagery. It was found that although the second method was slower, it produced consistent and, thereby, more useful APs. The SES is an integral part of a control system that will enable a robot to learn new behaviors based on its previous experiences, and that will enable it to recombine its known behaviors in such a way as to solve related, but novel, task problems with apparent creativity. The approach is to combine sensory-motor data association and dimensionality reduction to learn navigation and manipulation tasks as sequences of basic behaviors that can be implemented with a small set of closed-loop controllers. Over time, the aggregate of behaviors and their transition probabilities form a stochastic network. Then given a task, the robot finds a path in the network that leads from its current state to the goal. The SES provides a short-term memory for the cognitive functions of the robot, association of sensory and motor data via spatio-temporal coincidence, direction of the attention of the robot, navigation through spatial localization with respect to known or discovered landmarks, and structured data sharing between the robot and human team members, the individuals in multi-robot teams, or with a C3 center.

  3. Design, Qualification and Lessons Learned of the Shutter Calibration Mechanism for EnMAP Mission

    Science.gov (United States)

    Schmidt, Tilo; Muller, Silvio; Bergander, Arvid; Zajac, Kai; Seifart, Klaus

    2015-09-01

    The Shutter Calibration Mechanism (SCM) Assembly is one of three mechanisms which are developed by HTS for the EnMAP instrument in subcontract to OHB System AG Munich. EnMAP is the Environmental Mapping and Analysis Program of the German Space Agency DLR.The binary rotary encoder of the SCM using hall-effect sensors was already presented during ESMATS 2011. This paper summarizes the main functions and design features of the Hardware and focuses on qualification testing which has finished successfully in 2014. Of particular interest is the functional testing of the main drive including the precise hall-effect position sensing system and the test of the fail safe mechanism. In addition to standard test campaign required for QM also a shock emission measurement of the fail safe mechanism activation was conducted.Test conduction and results will be presented with focus on deviations from the expected behaviour, mitigation measures and on lessons learned.

  4. Can Probability Maps of Swept-Source Optical Coherence Tomography Predict Visual Field Changes in Preperimetric Glaucoma?

    Science.gov (United States)

    Lee, Won June; Kim, Young Kook; Jeoung, Jin Wook; Park, Ki Ho

    2017-12-01

    To determine the usefulness of swept-source optical coherence tomography (SS-OCT) probability maps in detecting locations with significant reduction in visual field (VF) sensitivity or predicting future VF changes, in patients with classically defined preperimetric glaucoma (PPG). Of 43 PPG patients, 43 eyes were followed-up on every 6 months for at least 2 years were analyzed in this longitudinal study. The patients underwent wide-field SS-OCT scanning and standard automated perimetry (SAP) at the time of enrollment. With this wide-scan protocol, probability maps originating from the corresponding thickness map and overlapped with SAP VF test points could be generated. We evaluated the vulnerable VF points with SS-OCT probability maps as well as the prevalence of locations with significant VF reduction or subsequent VF changes observed in the corresponding damaged areas of the probability maps. The vulnerable VF points were shown in superior and inferior arcuate patterns near the central fixation. In 19 of 43 PPG eyes (44.2%), significant reduction in baseline VF was detected within the areas of structural change on the SS-OCT probability maps. In 16 of 43 PPG eyes (37.2%), subsequent VF changes within the areas of SS-OCT probability map change were observed over the course of the follow-up. Structural changes on SS-OCT probability maps could detect or predict VF changes using SAP, in a considerable number of PPG eyes. Careful comparison of probability maps with SAP results could be useful in diagnosing and monitoring PPG patients in the clinical setting.

  5. SNPexp - A web tool for calculating and visualizing correlation between HapMap genotypes and gene expression levels

    Directory of Open Access Journals (Sweden)

    Franke Andre

    2010-12-01

    Full Text Available Abstract Background Expression levels for 47294 transcripts in lymphoblastoid cell lines from all 270 HapMap phase II individuals, and genotypes (both HapMap phase II and III of 3.96 million single nucleotide polymorphisms (SNPs in the same individuals are publicly available. We aimed to generate a user-friendly web based tool for visualization of the correlation between SNP genotypes within a specified genomic region and a gene of interest, which is also well-known as an expression quantitative trait locus (eQTL analysis. Results SNPexp is implemented as a server-side script, and publicly available on this website: http://tinyurl.com/snpexp. Correlation between genotype and transcript expression levels are calculated by performing linear regression and the Wald test as implemented in PLINK and visualized using the UCSC Genome Browser. Validation of SNPexp using previously published eQTLs yielded comparable results. Conclusions SNPexp provides a convenient and platform-independent way to calculate and visualize the correlation between HapMap genotypes within a specified genetic region anywhere in the genome and gene expression levels. This allows for investigation of both cis and trans effects. The web interface and utilization of publicly available and widely used software resources makes it an attractive supplement to more advanced bioinformatic tools. For the advanced user the program can be used on a local computer on custom datasets.

  6. Disproportionate distribution of field potentials across the toad's tectal visual map in response to diffuse light ON and OFF stimulations.

    Science.gov (United States)

    Schwippert, W W; Beneke, T W; Ewert, J P

    1996-01-01

    In toads Bufo marinus and Bufo bufo spinosus, field potentials (FPs) were recorded from the surface of the optic tectum at different sites of the visual map in response to a sudden diffuse darkening (OFF) and lightening (ON) of the visual field of the contralateral eye. The OFF and ON responses were differently pronounced or even failed to occur. The latency of the former was significantly less than the one of the latter. FP amplitudes of the OFF and ON responses were strongest in the representation of a horizonto-superior anterio-lateral portion of the visual field and weakest toward the posterior field of vision. This phenomenon suggests various interpretations for subsequent experiments.

  7. Building Keypoint Mappings on Multispectral Images by a Cascade of Classifiers with a Resurrection Mechanism

    Directory of Open Access Journals (Sweden)

    Yong Li

    2015-05-01

    Full Text Available Inspired by the boosting technique for detecting objects, this paper proposes a cascade structure with a resurrection mechanism to establish keypoint mappings on multispectral images. The cascade structure is composed of four steps by utilizing best bin first (BBF, color and intensity distribution of segment (CIDS, global information and the RANSAC process to remove outlier keypoint matchings. Initial keypoint mappings are built with the descriptors associated with keypoints; then, at each step, only a small number of keypoint mappings of a high confidence are classified to be incorrect. The unclassified keypoint mappings will be passed on to subsequent steps for determining whether they are correct. Due to the drawback of a classification rule, some correct keypoint mappings may be misclassified as incorrect at a step. Observing this, we design a resurrection mechanism, so that they will be reconsidered and evaluated by the rules utilized in subsequent steps. Experimental results show that the proposed cascade structure combined with the resurrection mechanism can effectively build more reliable keypoint mappings on multispectral images than existing methods.

  8. Persistent visual impairment in multiple sclerosis: prevalence, mechanisms and resulting disability.

    Science.gov (United States)

    Jasse, Laurence; Vukusic, Sandra; Durand-Dubief, Françoise; Vartin, Cristina; Piras, Carolina; Bernard, Martine; Pélisson, Denis; Confavreux, Christian; Vighetto, Alain; Tilikete, Caroline

    2013-10-01

    The objective of this article is to evaluate in multiple sclerosis (MS) patients the prevalence of persistent complaints of visual disturbances and the mechanisms and resulting functional disability of persistent visual complaints (PVCs). Firstly, the prevalence of PVCs was calculated in 303 MS patients. MS-related data of patients with or without PVCs were compared. Secondly, 70 patients with PVCs performed an extensive neuro-ophthalmologic assessment and a vision-related quality of life questionnaire, the National Eye Institute Visual Functionary Questionnaire (NEI-VFQ-25). PVCs were reported in 105 MS patients (34.6%). Patients with PVCs had more frequently primary progressive MS (30.5% vs 13.6%) and more neuro-ophthalmologic relapses (1.97 vs 1.36) than patients without PVCs. In the mechanisms/disability study, an afferent visual and an ocular-motor pathways dysfunction were respectively diagnosed in 41 and 59 patients, mostly related to bilateral optic neuropathy and bilateral internuclear ophthalmoplegia. The NEI-VFQ 25 score was poor and significantly correlated with the number of impaired neuro-ophthalmologic tests. Our study emphasizes the high prevalence of PVC in MS patients. Regarding the nature of neuro-ophthalmologic deficit, our results suggest that persistent optic neuropathy, as part of the progressive evolution of the disease, is not rare. We also demonstrate that isolated ocular motor dysfunctions induce visual disability in daily life.

  9. High-Resolution Remotely Sensed Small Target Detection by Imitating Fly Visual Perception Mechanism

    Directory of Open Access Journals (Sweden)

    Fengchen Huang

    2012-01-01

    Full Text Available The difficulty and limitation of small target detection methods for high-resolution remote sensing data have been a recent research hot spot. Inspired by the information capture and processing theory of fly visual system, this paper endeavors to construct a characterized model of information perception and make use of the advantages of fast and accurate small target detection under complex varied nature environment. The proposed model forms a theoretical basis of small target detection for high-resolution remote sensing data. After the comparison of prevailing simulation mechanism behind fly visual systems, we propose a fly-imitated visual system method of information processing for high-resolution remote sensing data. A small target detector and corresponding detection algorithm are designed by simulating the mechanism of information acquisition, compression, and fusion of fly visual system and the function of pool cell and the character of nonlinear self-adaption. Experiments verify the feasibility and rationality of the proposed small target detection model and fly-imitated visual perception method.

  10. High-resolution remotely sensed small target detection by imitating fly visual perception mechanism.

    Science.gov (United States)

    Huang, Fengchen; Xu, Lizhong; Li, Min; Tang, Min

    2012-01-01

    The difficulty and limitation of small target detection methods for high-resolution remote sensing data have been a recent research hot spot. Inspired by the information capture and processing theory of fly visual system, this paper endeavors to construct a characterized model of information perception and make use of the advantages of fast and accurate small target detection under complex varied nature environment. The proposed model forms a theoretical basis of small target detection for high-resolution remote sensing data. After the comparison of prevailing simulation mechanism behind fly visual systems, we propose a fly-imitated visual system method of information processing for high-resolution remote sensing data. A small target detector and corresponding detection algorithm are designed by simulating the mechanism of information acquisition, compression, and fusion of fly visual system and the function of pool cell and the character of nonlinear self-adaption. Experiments verify the feasibility and rationality of the proposed small target detection model and fly-imitated visual perception method.

  11. Retinotopic Maps, Spatial Tuning, and Locations of Human Visual Areas in Surface Coordinates Characterized with Multifocal and Blocked fMRI Designs

    Science.gov (United States)

    Henriksson, Linda; Karvonen, Juha; Salminen-Vaparanta, Niina; Railo, Henry; Vanni, Simo

    2012-01-01

    The localization of visual areas in the human cortex is typically based on mapping the retinotopic organization with functional magnetic resonance imaging (fMRI). The most common approach is to encode the response phase for a slowly moving visual stimulus and to present the result on an individual's reconstructed cortical surface. The main aims of this study were to develop complementary general linear model (GLM)-based retinotopic mapping methods and to characterize the inter-individual variability of the visual area positions on the cortical surface. We studied 15 subjects with two methods: a 24-region multifocal checkerboard stimulus and a blocked presentation of object stimuli at different visual field locations. The retinotopic maps were based on weighted averaging of the GLM parameter estimates for the stimulus regions. In addition to localizing visual areas, both methods could be used to localize multiple retinotopic regions-of-interest. The two methods yielded consistent retinotopic maps in the visual areas V1, V2, V3, hV4, and V3AB. In the higher-level areas IPS0, VO1, LO1, LO2, TO1, and TO2, retinotopy could only be mapped with the blocked stimulus presentation. The gradual widening of spatial tuning and an increase in the responses to stimuli in the ipsilateral visual field along the hierarchy of visual areas likely reflected the increase in the average receptive field size. Finally, after registration to Freesurfer's surface-based atlas of the human cerebral cortex, we calculated the mean and variability of the visual area positions in the spherical surface-based coordinate system and generated probability maps of the visual areas on the average cortical surface. The inter-individual variability in the area locations decreased when the midpoints were calculated along the spherical cortical surface compared with volumetric coordinates. These results can facilitate both analysis of individual functional anatomy and comparisons of visual cortex topology

  12. MARs Tools for Interactive ANalysis (MARTIAN): Google Maps Tools for Visual Exploration of Geophysical Modeling on Mars

    Science.gov (United States)

    Dimitrova, L. L.; Haines, M.; Holt, W. E.; Schultz, R. A.; Richard, G.; Haines, A. J.

    2006-12-01

    Interactive maps of surface-breaking faults and stress models on Mars provide important tools to engage undergraduate students, educators, and scientists with current geological and geophysical research. We have developed a map based on the Google Maps API -- an Internet based tool combining DHTML and AJAX, -- which allows very large maps to be viewed over the World Wide Web. Typically, small portions of the maps are downloaded as needed, rather than the entire image at once. This set-up enables relatively fast access for users with low bandwidth. Furthermore, Google Maps provides an extensible interactive interface making it ideal for visualizing multiple data sets at the user's choice. The Google Maps API works primarily with data referenced to latitudes and longitudes, which is then mapped in Mercator projection only. We have developed utilities for general cylindrical coordinate systems by converting these coordinates into equivalent Mercator projection before including them on the map. The MARTIAN project is available at http://rock.geo.sunysb.edu/~holt/Mars/MARTIAN/. We begin with an introduction to the Martian surface using a topography model. Faults from several datasets are classified by type (extension vs. compression) and by time epoch. Deviatoric stresses due to gravitational potential energy differences, calculated from the topography and crustal thickness, can be overlain. Several quantitative measures for the fit of the stress field to the faults are also included. We provide introductory text and exercises spanning a range of topics: how are faults identified, what stress is and how it relates to faults, what gravitational potential energy is and how variations in it produce stress, how the models are created, and how these models can be evaluated and interpreted. The MARTIAN tool is used at Stony Brook University in GEO 310: Introduction to Geophysics, a class geared towards junior and senior geosciences majors. Although this project is in its

  13. Femtosecond laser versus mechanical microkeratome: a retrospective comparison of visual outcomes at 3 months.

    Science.gov (United States)

    Tanna, Mesha; Schallhorn, Steven C; Hettinger, Keith A

    2009-07-01

    To compare the visual outcomes of LASIK procedures in which flaps were created with a femtosecond laser (IntraLase FS 60Hz, Abbott Medical Optics [AMO]) to procedures in which flaps were created with a mechanical microkeratome (Moria Evo3 One Use-Plus, Moria SA). A retrospective analysis was performed on 2000 eyes treated in 2008 for low myopia and astigmatism (sphere mechanical microkeratome. All eyes received wavefront-guided LASIK treatments performed with a VISX S4 IR Advanced CustomVue excimer laser (AMO). Refractive predictability, change in mean spherical equivalent refraction, postoperative uncorrected visual acuity (UCVA), and loss of best spectacle-corrected visual acuity (BSCVA) were compared at 1 day, 1 week, 1 month, and 3 months following surgery. The refractive accuracy was the same for both groups. At all time points measured, the percentage of eyes that achieved a postoperative UCVA of 20/20 or better was significantly higher in the femtosecond laser group than in the mechanical keratome group. Also, a higher percentage of eyes in the femtosecond laser group achieved a postoperative UCVA of 20/16 at 3 months. Finally, a lower percentage of eyes in the femtosecond laser group lost two or more lines of BSCVA at 1 week and 1 month postoperative. Creating LASIK flaps with the femtosecond laser resulted in faster visual recovery and better UCVA.

  14. Impaired Letter-String Processing in Developmental Dyslexia: What Visual-to-Phonology Code Mapping Disorder?

    Science.gov (United States)

    Valdois, Sylviane; Lassus-Sangosse, Delphine; Lobier, Muriel

    2012-01-01

    Poor parallel letter-string processing in developmental dyslexia was taken as evidence of poor visual attention (VA) span, that is, a limitation of visual attentional resources that affects multi-character processing. However, the use of letter stimuli in oral report tasks was challenged on its capacity to highlight a VA span disorder. In…

  15. Mapping Disciplinary Values and Rhetorical Concerns through Language: Writing Instruction in the Performing and Visual Arts

    Science.gov (United States)

    Cox, Anicca

    2015-01-01

    Via interview data focused on instructor practices and values, this study sought to describe some of what performing and visual arts instructors do at the university level to effectively teach disciplinary values through writing. The study's research goals explored how relationships to writing process in visual and performing arts support…

  16. Visual Mapping of Sedimentary Facies Can Yield Accurate And Geomorphically Meaningful Results at Morphological Unit to River Segment Scales

    Science.gov (United States)

    Pasternack, G. B.; Wyrick, J. R.; Jackson, J. R.

    2014-12-01

    Long practiced in fisheries, visual substrate mapping of coarse-bedded rivers is eschewed by geomorphologists for inaccuracy and limited sizing data. Geomorphologists perform time-consuming measurements of surficial grains, with the few locations precluding spatially explicit mapping and analysis of sediment facies. Remote sensing works for bare land, but not vegetated or subaqueous sediments. As visual systems apply the log2 Wentworth scale made for sieving, they suffer from human inability to readily discern those classes. We hypothesized that size classes centered on the PDF of the anticipated sediment size distribution would enable field crews to accurately (i) identify presence/absence of each class in a facies patch and (ii) estimate the relative amount of each class to within 10%. We first tested 6 people using 14 measured samples with different mixtures. Next, we carried out facies mapping for ~ 37 km of the lower Yuba River in California. Finally, we tested the resulting data to see if it produced statistically significant hydraulic-sedimentary-geomorphic results. Presence/absence performance error was 0-4% for four people, 13% for one person, and 33% for one person. The last person was excluded from further effort. For the abundance estimation performance error was 1% for one person, 7-12% for three people, and 33% for one person. This last person was further trained and re-tested. We found that the samples easiest to visually quantify were unimodal and bimodal, while those most difficult had nearly equal amounts of each size. This confirms psychological studies showing that humans have a more difficult time quantifying abundances of subgroups when confronted with well-mixed groups. In the Yuba, mean grain size decreased downstream, as is typical for an alluvial river. When averaged by reach, mean grain size and bed slope were correlated with an r2 of 0.95. At the morphological unit (MU) scale, eight in-channel bed MU types had an r2 of 0.90 between mean

  17. Circuit Mechanisms Governing Local vs. Global Motion Processing in Mouse Visual Cortex

    DEFF Research Database (Denmark)

    Rasmussen, Rune; Yonehara, Keisuke

    2017-01-01

    literature on global motion processing based on works in primates and mice. Lastly, we propose what types of experiments could illuminate what circuit mechanisms are governing cortical global visual motion processing. We propose that PDS cells in mouse visual cortex appear as the perfect arena...... for delineating and solving how individual sensory features extracted by neural circuits in peripheral brain areas are integrated to build our rich cohesive sensory experiences.......A withstanding question in neuroscience is how neural circuits encode representations and perceptions of the external world. A particularly well-defined visual computation is the representation of global object motion by pattern direction-selective (PDS) cells from convergence of motion of local...

  18. Direct Visualization of Mechanical Beats by Means of an Oscillating Smartphone

    Science.gov (United States)

    Giménez, Marcos H.; Salinas, Isabel; Monsoriu, Juan A.; Castro-Palacio, Juan C.

    2017-10-01

    The resonance phenomenon is widely known in physics courses. Qualitatively speaking, resonance takes place in a driven oscillating system whenever the frequency approaches the natural frequency, resulting in maximal oscillatory amplitude. Very closely related to resonance is the phenomenon of mechanical beating, which occurs when the driving and natural frequencies of the system are slightly different. The frequency of the beat is just the difference of the natural and driving frequencies. Beats are very familiar in acoustic systems. There are several works in this journal on visualizing the beats in acoustic systems. For instance, the microphone and the speaker of two mobile devices were used in previous work to analyze the acoustic beats produced by two signals of close frequencies. The formation of beats can also be visualized in mechanical systems, such as a mass-spring system or a double-driven string. Here, the mechanical beats in a smartphone-spring system are directly visualized in a simple way. The frequency of the beats is measured by means of the acceleration sensor of a smartphone, which hangs from a spring attached to a mechanical driver. This laboratory experiment is suitable for both high school and first-year university physics courses.

  19. Stakeholder approach, Stakeholders mental model: A visualization test with cognitive mapping technique

    OpenAIRE

    Garoui Nassreddine; Jarboui Anis

    2012-01-01

    The idea of this paper is to determine the mental models of actors in the firm with respect to the stakeholder approach of corporate governance. The use of the cognitive map to view these diagrams to show the ways of thinking and conceptualization of the stakeholder approach. The paper takes a corporate governance perspective, discusses stakeholder model. It takes also a cognitive mapping technique.

  20. Participatory Mapping with Urban Youth: The Visual Elicitation of Socio-Spatial Research Data

    Science.gov (United States)

    Literat, Ioana

    2013-01-01

    Participatory mapping attempts to engage youth in the generation of personalized maps, as a way to both harness the value of individual knowledge about geographic space, and to concurrently empower the research participants by inviting them to take an active stake in the representation and explication of their spatial environment. Engagement in…

  1. A novel continuous colour mapping approach for visualization of facial skin hydration and transepidermal water loss for four ethnic groups.

    Science.gov (United States)

    Voegeli, R; Rawlings, A V; Seroul, P; Summers, B

    2015-12-01

    The aim of this exploratory study was to develop a novel colour mapping approach to visualize and interpret the complexity of facial skin hydration and barrier properties of four ethnic groups (Caucasians, Indians, Chinese and Black Africans) living in Pretoria, South Africa. We measured transepidermal water loss (TEWL) and skin capacitance on 30 pre-defined sites on the forehead, cheek, jaw and eye areas of sixteen women (four per ethnic group) and took digital images of their faces. Continuous colour maps were generated by interpolating between each measured value and superimposing the values on the digital images. The complexity of facial skin hydration and skin barrier properties is revealed by these measurements and visualized by the continuous colour maps of the digital images. Overall, the Caucasian subjects had the better barrier properties followed by the Black African subjects, Chinese subjects and Indian subjects. Nevertheless, the two more darkly pigmented ethnic groups had superior skin hydration properties. Subtle differences were seen when examining the different facial sites. There exists remarkable skin capacitance and TEWL gradients within short distances on selected areas of the face. These gradients are distinctive in the different ethnic groups. In contrast to other reports, we found that darkly pigmented skin does not always have a superior barrier function and differences in skin hydration values are complex on the different parts of the face among the different ethnic groups. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  2. Arctic Research Mapping Application (ARMAP): visualize project-level information for U.S. funded research in the Arctic

    Science.gov (United States)

    Kassin, A.; Cody, R. P.; Barba, M.; Escarzaga, S. M.; Score, R.; Dover, M.; Gaylord, A. G.; Manley, W. F.; Habermann, T.; Tweedie, C. E.

    2015-12-01

    The Arctic Research Mapping Application (ARMAP; http://armap.org/) is a suite of online applications and data services that support Arctic science by providing project tracking information (who's doing what, when and where in the region) for United States Government funded projects. In collaboration with 17 research agencies, project locations are displayed in a visually enhanced web mapping application. Key information about each project is presented along with links to web pages that provide additional information. The mapping application includes new reference data layers and an updated ship tracks layer. Visual enhancements are achieved by redeveloping the front-end from FLEX to HTML5 and JavaScript, which now provide access to mobile users utilizing tablets and cell phone devices. New tools have been added that allow users to navigate, select, draw, measure, print, use a time slider, and more. Other module additions include a back-end Apache SOLR search platform that provides users with the capability to perform advance searches throughout the ARMAP database. Furthermore, a new query builder interface has been developed in order to provide more intuitive controls to generate complex queries. These improvements have been made to increase awareness of projects funded by numerous entities in the Arctic, enhance coordination for logistics support, help identify geographic gaps in research efforts and potentially foster more collaboration amongst researchers working in the region. Additionally, ARMAP can be used to demonstrate past, present, and future research efforts supported by the U.S. Government.

  3. Using GeoMapApp as an Analytical Tool for the Journey From Data Visualization to Synthesis

    Science.gov (United States)

    Ryan, W. B.; Coplan, J. O.; Melkonian, A. K.; Carbotte, S. M.

    2008-12-01

    The potential to explore and understand our world has forever changed since the appearance of the NASA World Wind and Google Earth virtual globes. Now, in the duration of a single breath, we can zoom from the planetary scale of an orbiting spacecraft down to a roadside outcrop and expose layers of information with different and rich contents. But how do we digest all this information into new knowledge that explains the processes that have shaped the land and oceans into their present configurations and behaviors? In our opinion we need to transition beyond visualization to interactive inquiry of multiple datasets across a span of expertise - from the classroom to the research laboratory. Although the virtual globe enables an unprecedented means as revolutionary as the textural search engine to discover information, presently most data on the WEB are not adequately described with metadata to make the subsequent steps of analysis productive. We have begun to address this limitation by linking GeoMapApp to databases in the earth and ocean sciences where content has been vetted for thoroughness, accuracy and global coverage. With structure in the content, the virtual globe can then manipulate these databases in what if? exercises, compare the various attributes of a dataset with each other via graphs and symbols, and correlate results across different scientific domains. We will show examples of such data integration using the results of four decades of ocean floor drilling, the focal mechanisms from thousands of earthquakes, and the chemistry of the volcanic bedrock along the crest of the mid-ocean ridge. A synthesis of ocean drilling shows the dependency of the sediment and faunal content on bedrock age, subsidence history and plate motions relative to the past equator and deserts. A synthesis of earthquake rupture shows focal mechanism dependency on segmentation of the plate boundaries. Patterns in the chemistry of erupted lava are intricately related to the fine

  4. To be selected or not to be selected : a modeling and behavioral study of the mechanisms underlying stimulus-driven and top-down visual attention

    NARCIS (Netherlands)

    Voort van der Kleij, van der Gwendid T.

    2007-01-01

    This thesis investigates the mechanisms of stimulus-driven visual attention (global saliency), the mechanisms of top-down visual attention, and the interaction between these mechanisms, in visual search. Following the outline of an existing model of top-down visual attention, namely the Closed-Loop

  5. Comparable mechanisms of working memory interference by auditory and visual motion in youth and aging.

    Science.gov (United States)

    Mishra, Jyoti; Zanto, Theodore; Nilakantan, Aneesha; Gazzaley, Adam

    2013-08-01

    Intrasensory interference during visual working memory (WM) maintenance by object stimuli (such as faces and scenes), has been shown to negatively impact WM performance, with greater detrimental impacts of interference observed in aging. Here we assessed age-related impacts by intrasensory WM interference from lower-level stimulus features such as visual and auditory motion stimuli. We consistently found that interference in the form of ignored distractions and secondary task interruptions presented during a WM maintenance period, degraded memory accuracy in both the visual and auditory domain. However, in contrast to prior studies assessing WM for visual object stimuli, feature-based interference effects were not observed to be significantly greater in older adults. Analyses of neural oscillations in the alpha frequency band further revealed preserved mechanisms of interference processing in terms of post-stimulus alpha suppression, which was observed maximally for secondary task interruptions in visual and auditory modalities in both younger and older adults. These results suggest that age-related sensitivity of WM to interference may be limited to complex object stimuli, at least at low WM loads. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Programs for visualization, handling and quantification of PIXE maps at the AGLAE facility

    Energy Technology Data Exchange (ETDEWEB)

    Pichon, L., E-mail: laurent.pichon@culture.fr [Centre de recherche et de restauration des musées de France, C2RMF, Palais du Louvre – Porte des Lions, 14 Quai François Mitterrand, 75001 Paris (France); Fédération de recherche NewAGLAE, FR3506 CNRS, Ministère de la Culture et de la Communication, Chimie ParisTech, Palais du Louvre, 75001 Paris (France); Calligaro, T. [Centre de recherche et de restauration des musées de France, C2RMF, Palais du Louvre – Porte des Lions, 14 Quai François Mitterrand, 75001 Paris (France); Fédération de recherche NewAGLAE, FR3506 CNRS, Ministère de la Culture et de la Communication, Chimie ParisTech, Palais du Louvre, 75001 Paris (France); PSL Research University, Chimie ParisTech-CNRS, Institut de Recherche Chimie Paris, UMR8247, 75005 Paris (France); Lemasson, Q.; Moignard, B.; Pacheco, C. [Centre de recherche et de restauration des musées de France, C2RMF, Palais du Louvre – Porte des Lions, 14 Quai François Mitterrand, 75001 Paris (France); Fédération de recherche NewAGLAE, FR3506 CNRS, Ministère de la Culture et de la Communication, Chimie ParisTech, Palais du Louvre, 75001 Paris (France)

    2015-11-15

    The external beam setup of the AGLAE facility has been developed in order to combine PIXE with PIGE, EBS and recently IBIL for the analysis of cultural heritage artefacts. The upgraded external beam end-station integrates five large solid angle X-ray detectors either to reduce the risk of damage on sensitive artworks by decreasing the beam intensity or to routinely acquire elemental maps at various scales. While many programs are available to process PIXE maps acquired with nuclear microprobes, a software to process the major and trace elements PIXE maps point by point using GUPIX is not available. The present paper describes three programs developed for the AGLAE facility to process numerous maps obtained with multiple detectors. AGLAEMAP allows to handle maps and pixel groups within maps, TRAUPIXE to process quantitatively PIXE spectra of all pixels and DATAIMAGING to display the resulting quantitative elemental maps. The benefits of this software suite are demonstrated by processing a dataset acquired on a pellet of geostandard reference material and on a terre mêlée pottery shard sample created by the famous ceramist Bernard Palissy (1510–1589), highlighting chemical elements present in this polychrome ceramic.

  7. Diffusion-Based Density-Equalizing Maps: an Interdisciplinary Approach to Visualizing Homicide Rates and Other Georeferenced Statistical Data

    CERN Document Server

    Mazzitello, Karina I

    2012-01-01

    In every country, public and private agencies allocate extensive funding to collect large-scale statistical data, which in turn are studied and analyzed in order to determine local, regional, national, and international policies regarding all aspects relevant to the welfare of society. One important aspect of that process is the visualization of statistical data with embedded geographical information, which most often relies on archaic methods such as maps colored according to graded scales. In this work, we apply non-standard visualization techniques based on physical principles. We illustrate the method with recent statistics on homicide rates in Brazil and their correlation to other publicly available data. This physics-based approach provides a novel tool that can be used by interdisciplinary teams investigating statistics and model projections in a variety of fields such as economics and gross domestic product research, public health and epidemiology, socio-demographics, political science, business and m...

  8. Diffusion-Based Density-Equalizing Maps: an Interdisciplinary Approach to Visualizing Homicide Rates and Other Georeferenced Statistical Data

    Science.gov (United States)

    Mazzitello, Karina I.; Candia, Julián

    2012-12-01

    In every country, public and private agencies allocate extensive funding to collect large-scale statistical data, which in turn are studied and analyzed in order to determine local, regional, national, and international policies regarding all aspects relevant to the welfare of society. One important aspect of that process is the visualization of statistical data with embedded geographical information, which most often relies on archaic methods such as maps colored according to graded scales. In this work, we apply nonstandard visualization techniques based on physical principles. We illustrate the method with recent statistics on homicide rates in Brazil and their correlation to other publicly available data. This physics-based approach provides a novel tool that can be used by interdisciplinary teams investigating statistics and model projections in a variety of fields such as economics and gross domestic product research, public health and epidemiology, sociodemographics, political science, business and marketing, and many others.

  9. Multi-slice CT for visualization of pulmonary embolism using perfusion weighted color maps

    Energy Technology Data Exchange (ETDEWEB)

    Wildberger, J.E.; Wein, B.B.; Guenther, R.W. [Univ. of Technology, Aachen (Germany). Dept. of Diagnostic Radiology; Niethammer, M.U.; Klotz, E.; Schaller, S. [Siemens Medical Engineering, Computed Tomography, Forchheim (Germany)

    2001-04-01

    Purpose: The purpose of our preliminary study was to evaluate the feasibility of a new technique for the perfusion weighted color display of the density of lung parenchyma derived from multi-slice CT (MSCT) data sets of clinical routine examinations for visualization of pulmonary embolism (PE). Materials and Methods: Imaging of patients with suspected PE was performed on a commercially available MSCT (Somatom Volume Zoom; Siemens, Forchheim, Germany) after intravenous application of 120 cc of contrast-medium using a power injector. Scan parameters were 140 kV and 100 mAs, using a thin collimation of 4x1 mm and a table speed of 7 mm (pitch: 1.75). Derived from thin collimation axial slices (slice thickness{sub eff.} 1.25 mm, reconstruction increment 0.8 mm), a new image processing technique was deployed. Based on these source images, an automated 3D-segmentation of the lungs was performed followed by threshold based extraction of major airways and vascular structures. The filtered volume data were color encordes and finally overlayed onto the original CT images. This color encoded display of parenchymal density distribution of the lungs was shown in axial, coronal and sagittal plans orientation. In four patients with excluded PE as well as in two patients with proven PE this new technique was performed. Results: In the four patients that were considered negative regarding PE on MSCT, lung densitometry showed a homogeneous distribution of color encoded densities without circumscribed decreased or increased areas, beside the usually present gravity-dependent gradient in ventro-dorsal direction. In the two patients with proven PE, low density values on perfusion weighted color maps were found distally to the occluded pulmonary arteries. (orig.) [German] Einleitung: Ziel unserer Studie war die Erprobung einer neuen farbkodierten Darstellung des Lungenparenchyms an Patienten mit Verdacht auf Lungenembolie (LE) anhand von Mehrschicht-Spiral CT (MSCT) Datensaetzen aus der

  10. Brain SPECT in mesial temporal lobe epilepsy: comparison between visual analysis and SPM (Statistical Parametric Mapping)

    Energy Technology Data Exchange (ETDEWEB)

    Amorim, Barbara Juarez; Ramos, Celso Dario; Santos, Allan Oliveira dos; Lima, Mariana da Cunha Lopes de; Camargo, Edwaldo Eduardo; Etchebehere, Elba Cristina Sa de Camargo, E-mail: juarezbarbara@hotmail.co [State University of Campinas (UNICAMP), SP (Brazil). School of Medical Sciences. Dept. of Radiology; Min, Li Li; Cendes, Fernando [State University of Campinas (UNICAMP), SP (Brazil). School of Medical Sciences. Dept. of Neurology

    2010-04-15

    Objective: to compare the accuracy of SPM and visual analysis of brain SPECT in patients with mesial temporal lobe epilepsy (MTLE). Method: interictal and ictal SPECTs of 22 patients with MTLE were performed. Visual analysis were performed in interictal (VISUAL(inter)) and ictal (VISUAL(ictal/inter)) studies. SPM analysis consisted of comparing interictal (SPM(inter)) and ictal SPECTs (SPM(ictal)) of each patient to control group and by comparing perfusion of temporal lobes in ictal and interictal studies among themselves (SPM(ictal/inter)). Results: for detection of the epileptogenic focus, the sensitivities were as follows: VISUAL(inter)=68%; VISUAL(ictal/inter)=100%; SPM(inter)=45%; SPM(ictal)=64% and SPM(ictal/inter)=77%. SPM was able to detect more areas of hyperperfusion and hypoperfusion. Conclusion: SPM did not improve the sensitivity to detect epileptogenic focus. However, SPM detected different regions of hypoperfusion and hyperperfusion and is therefore a helpful tool for better understand pathophysiology of seizures in MTLE. (author)

  11. Visualizing fossilization using laser ablation-inductively coupled plasma-mass spectrometry maps of trace elements in Late Cretaceous bones

    Science.gov (United States)

    Koenig, A.E.; Rogers, R.R.; Trueman, C.N.

    2009-01-01

    Elemental maps generated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) provide a previously unavailable high-resolution visualization of the complex physicochemical conditions operating within individual bones during the early stages of diagenesis and fossilization. A selection of LA-ICP-MS maps of bones collected from the Late Cretaceous of Montana (United States) and Madagascar graphically illustrate diverse paths to recrystallization, and reveal unique insights into geochemical aspects of taphonomic history. Some bones show distinct gradients in concentrations of rare earth elements and uranium, with highest concentrations at external bone margins. Others exhibit more intricate patterns of trace element uptake related to bone histology and its control on the flow paths of pore waters. Patterns of element uptake as revealed by LA-ICP-MS maps can be used to guide sampling strategies, and call into question previous studies that hinge upon localized bulk samples of fossilized bone tissue. LA-ICP-MS maps also allow for comparison of recrystallization rates among fossil bones, and afford a novel approach to identifying bones or regions of bones potentially suitable for extracting intact biogeochemical signals. ?? 2009 Geological Society of America.

  12. Computer-Based Concept Mapping: Enhancing Literacy with Tools for Visual Thinking (Technology Tidbits).

    Science.gov (United States)

    Anderson-Inman, Lynne; Horney, Mark

    1997-01-01

    Shares details about two prewriting strategies (brainstorming and synthesizing information), and discusses some practical issues related to the use of computer-based concept mapping in the classroom. (SR)

  13. Stakeholder approach, Stakeholders mental model: A visualization test with cognitive mapping technique

    Directory of Open Access Journals (Sweden)

    Garoui Nassreddine

    2012-04-01

    Full Text Available The idea of this paper is to determine the mental models of actors in the firm with respect to the stakeholder approach of corporate governance. The use of the cognitive map to view these diagrams to show the ways of thinking and conceptualization of the stakeholder approach. The paper takes a corporate governance perspective, discusses stakeholder model. It takes also a cognitive mapping technique.

  14. Rapid development of cognitive maps in people with visual impairments when exploring novel geographic spaces

    OpenAIRE

    Jacobson, Dan; Lippa, Yvonne; Golledge, Reginald G.; Kitchin, Rob; Blades, Mark

    2001-01-01

    'Cognitive' map is a term that refers to a person's environmental knowledge. Anyone experiencing a new environment will, over time, develop a cognitive representation of that environment, including information derived from that environment (e.g., about places, routes and spatial relationships) and information about personal experiences (e.g. memories about events at locations and attitudes towards places). There is now a great deal of research into the cognitive maps of sighted people (see Go...

  15. a Study on Mental Representations for Realistic Visualization the Particular Case of Ski Trail Mapping

    Science.gov (United States)

    Balzarini, R.; Dalmasso, A.; Murat, M.

    2015-08-01

    This article presents preliminary results from a research project in progress that brings together geographers, cognitive scientists, historians and computer scientists. The project investigates the evolution of a particular territorial model: ski trails maps. Ski resorts, tourist and sporting innovations for mountain economies since the 1930s, have needed cartographic representations corresponding to new practices of the space.Painter artists have been involved in producing ski maps with painting techniques and panoramic views, which are by far the most common type of map, because they allow the resorts to look impressive to potential visitors. These techniques have evolved throughout the mutations of the ski resorts. Paper ski maps no longer meet the needs of a large part of the customers; the question now arises of their adaptation to digital media. In a computerized process perspective, the early stage of the project aims to identify the artist-representations, based on conceptual and technical rules, which are handled by users-skiers to perform a task (location, wayfinding, decision-making) and can be transferred to a computer system. This article presents the experimental phase that analyzes artist and user mental representations that are at stake during the making and the reading of a paper ski map. It particularly focuses on how the invention of the artist influences map reading.

  16. A STUDY ON MENTAL REPRESENTATIONS FOR REALISTIC VISUALIZATION THE PARTICULAR CASE OF SKI TRAIL MAPPING

    Directory of Open Access Journals (Sweden)

    R. Balzarini

    2015-08-01

    Full Text Available This article presents preliminary results from a research project in progress that brings together geographers, cognitive scientists, historians and computer scientists. The project investigates the evolution of a particular territorial model: ski trails maps. Ski resorts, tourist and sporting innovations for mountain economies since the 1930s, have needed cartographic representations corresponding to new practices of the space.Painter artists have been involved in producing ski maps with painting techniques and panoramic views, which are by far the most common type of map, because they allow the resorts to look impressive to potential visitors. These techniques have evolved throughout the mutations of the ski resorts. Paper ski maps no longer meet the needs of a large part of the customers; the question now arises of their adaptation to digital media. In a computerized process perspective, the early stage of the project aims to identify the artist-representations, based on conceptual and technical rules, which are handled by users-skiers to perform a task (location, wayfinding, decision-making and can be transferred to a computer system. This article presents the experimental phase that analyzes artist and user mental representations that are at stake during the making and the reading of a paper ski map. It particularly focuses on how the invention of the artist influences map reading.

  17. Visualization of hot spot formation in energetic materials under periodic mechanical excitation using phosphor thermography

    Science.gov (United States)

    Casey, Alex; Fenoglio, Gabriel; Detrinidad, Humberto

    2017-06-01

    Under mechanical excitation, energy is known to localize within an energetic material resulting in `hot spot' formation. While many formation mechanisms have been proposed, additional insight to heat generation mechanisms, the effect of binder/crystal interfaces, and predication capabilities can be gained by quantifying the initiation and growth of the hot spots. Phosphor thermography is a well established temperature sensing technique wherein an object's temperature is obtained by collecting the temperature dependent luminescence of an optically excited phosphor. Herein, the phosphor thermography technique has been applied to Dow Corning Sylgard® 184/octahydro 1,3,5,7 tetranitro 1,3,5,7 tetrazocine (HMX) composite materials under mechanical excitation in order to visualize the evolution of the temperature field, and thus hot spot formation, within the binder. Funded by AFOSR. Supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate Fellowship (NDSEG) Program.

  18. Rapid and minimum invasive functional brain mapping by real-time visualization of high gamma activity during awake craniotomy.

    Science.gov (United States)

    Ogawa, Hiroshi; Kamada, Kyousuke; Kapeller, Christoph; Hiroshima, Satoru; Prueckl, Robert; Guger, Christoph

    2014-11-01

    Electrocortical stimulation (ECS) is the gold standard for functional brain mapping during an awake craniotomy. The critical issue is to set aside enough time to identify eloquent cortices by ECS. High gamma activity (HGA) ranging between 80 and 120 Hz on electrocorticogram is assumed to reflect localized cortical processing. In this report, we used real-time HGA mapping and functional neuronavigation integrated with functional magnetic resonance imaging (fMRI) for rapid and reliable identification of motor and language functions. Four patients with intra-axial tumors in their dominant hemisphere underwent preoperative fMRI and lesion resection with an awake craniotomy. All patients showed significant fMRI activation evoked by motor and language tasks. During the craniotomy, we recorded electrocorticogram activity by placing subdural grids directly on the exposed brain surface. Each patient performed motor and language tasks and demonstrated real-time HGA dynamics in hand motor areas and parts of the inferior frontal gyrus. Sensitivity and specificity of HGA mapping were 100% compared with ECS mapping in the frontal lobe, which suggested HGA mapping precisely indicated eloquent cortices. We found different HGA dynamics of language tasks in frontal and temporal regions. Specificities of the motor and language-fMRI did not reach 85%. The results of HGA mapping was mostly consistent with those of ECS mapping, although fMRI tended to overestimate functional areas. This novel technique enables rapid and accurate identification of motor and frontal language areas. Furthermore, real-time HGA mapping sheds light on underlying physiological mechanisms related to human brain functions. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Development and validation of an achievement test in introductory quantum mechanics: The Quantum Mechanics Visualization Instrument (QMVI)

    Science.gov (United States)

    Cataloglu, Erdat

    The purpose of this study was to construct a valid and reliable multiple-choice achievement test to assess students' understanding of core concepts of introductory quantum mechanics. Development of the Quantum Mechanics Visualization Instrument (QMVI) occurred across four successive semesters in 1999--2001. During this time 213 undergraduate and graduate students attending the Pennsylvania State University (PSU) at University Park and Arizona State University (ASU) participated in this development and validation study. Participating students were enrolled in four distinct groups of courses: Modern Physics, Undergraduate Quantum Mechanics, Graduate Quantum Mechanics, and Chemistry Quantum Mechanics. Expert panels of professors of physics experienced in teaching quantum mechanics courses and graduate students in physics and science education established the core content and assisted in the validating of successive versions of the 24-question QMVI. Instrument development was guided by procedures outlined in the Standards for Educational and Psychological Testing (AERA-APA-NCME, 1999). Data gathered in this study provided information used in the development of successive versions of the QMVI. Data gathered in the final phase of administration of the QMVI also provided evidence that the intended score interpretation of the QMVI achievement test is valid and reliable. A moderate positive correlation coefficient of 0.49 was observed between the students' QMVI scores and their confidence levels. Analyses of variance indicated that students' scores in Graduate Quantum Mechanics and Undergraduate Quantum Mechanics courses were significantly higher than the mean scores of students in Modern Physics and Chemistry Quantum Mechanics courses (p < 0.05). That finding is consistent with the additional understanding and experience that should be anticipated in graduate students and junior-senior level students over sophomore physics majors and majors in another field. The moderate

  20. A Replication-Based Mechanism for Fault Tolerance in MapReduce Framework

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2015-01-01

    Full Text Available MapReduce is a programming model and an associated implementation for processing and generating large data sets with a parallel, distributed algorithm on a cluster. In cloud environment, node and task failure are no longer accidental but a common feature of large-scale systems. Current rescheduling-based fault tolerance method in MapReduce framework failed to fully consider the location of distributed data and the computation and storage overhead of rescheduling failure tasks. Thus, a single node failure will increase the completion time dramatically. In this paper, a replication-based mechanism is proposed, which takes both task and node failure into consideration. Experimental results show that, compared with default mechanism in Hadoop, our mechanism can significantly improve the performance at failure time, with more than 30% decreasing in execution time.

  1. Mapping brain activation and information during category-specific visual working memory.

    Science.gov (United States)

    Linden, David E J; Oosterhof, Nikolaas N; Klein, Christoph; Downing, Paul E

    2012-01-01

    How is working memory for different visual categories supported in the brain? Do the same principles of cortical specialization that govern the initial processing and encoding of visual stimuli also apply to their short-term maintenance? We investigated these questions with a delayed discrimination paradigm for faces, bodies, flowers, and scenes and applied both univariate and multivariate analyses to functional magnetic resonance imaging (fMRI) data. Activity during encoding followed the well-known specialization in posterior areas. During the delay interval, activity shifted to frontal and parietal regions but was not specialized for category. Conversely, activity in visual areas returned to baseline during that interval but showed some evidence of category specialization on multivariate pattern analysis (MVPA). We conclude that principles of cortical activation differ between encoding and maintenance of visual material. Whereas perceptual processes rely on specialized regions in occipitotemporal cortex, maintenance involves the activation of a frontoparietal network that seems to require little specialization at the category level. We also confirm previous findings that MVPA can extract information from fMRI signals in the absence of suprathreshold activation and that such signals from visual areas can reflect the material stored in memory.

  2. Aging of non-visual spectral sensitivity to light in humans: compensatory mechanisms?

    Directory of Open Access Journals (Sweden)

    Raymond P Najjar

    Full Text Available The deterioration of sleep in the older population is a prevalent feature that contributes to a decrease in quality of life. Inappropriate entrainment of the circadian clock by light is considered to contribute to the alteration of sleep structure and circadian rhythms in the elderly. The present study investigates the effects of aging on non-visual spectral sensitivity to light and tests the hypothesis that circadian disturbances are related to a decreased light transmittance. In a within-subject design, eight aged and five young subjects were exposed at night to 60 minute monochromatic light stimulations at 9 different wavelengths (420-620 nm. Individual sensitivity spectra were derived from measures of melatonin suppression. Lens density was assessed using a validated psychophysical technique. Although lens transmittance was decreased for short wavelength light in the older participants, melatonin suppression was not reduced. Peak of non-visual sensitivity was, however, shifted to longer wavelengths in the aged participants (494 nm compared to young (484 nm. Our results indicate that increased lens filtering does not necessarily lead to a decreased non-visual sensitivity to light. The lack of age-related decrease in non-visual sensitivity to light may involve as yet undefined adaptive mechanisms.

  3. Learning to read aligns visual analytical skills with grapheme-phoneme mapping: evidence from illiterates.

    Science.gov (United States)

    Lachmann, Thomas; Khera, Gunjan; Srinivasan, Narayanan; van Leeuwen, Cees

    2012-01-01

    Learning to read puts evolutionary established speech and visual object recognition functions to novel use. As we previously showed, this leads to particular rearrangements and differentiations in these functions, for instance the habitual preference for holistic perceptual organization in visual object recognition and its suppression in perceiving letters. We performed the experiment in which the differentiation between holistic non-letter processing and analytic letter processing in literates was originally shown (van Leeuwen and Lachmann, 2004) with illiterate adults. The original differentiation is absent in illiterates; they uniformly showed analytic perception for both letters and non-letters. The result implies that analytic visual perception is not a secondary development resulting from learning to read but, rather, a primary mode of perceptual organization on a par with holistic perception.

  4. Atomic Force Microscopy Mechanical Mapping of Micropatterned Cells Shows Adhesion Geometry-Dependent Mechanical Response on Local and Global Scales.

    Science.gov (United States)

    Rigato, Annafrancesca; Rico, Felix; Eghiaian, Frédéric; Piel, Mathieu; Scheuring, Simon

    2015-06-23

    In multicellular organisms, cell shape and organization are dictated by cell-cell or cell-extracellular matrix adhesion interactions. Adhesion complexes crosstalk with the cytoskeleton enabling cells to sense their mechanical environment. Unfortunately, most of cell biology studies, and cell mechanics studies in particular, are conducted on cultured cells adhering to a hard, homogeneous, and unconstrained substrate with nonspecific adhesion sites, thus far from physiological and reproducible conditions. Here, we grew cells on three different fibronectin patterns with identical overall dimensions but different geometries (▽, T, and Y), and investigated their topography and mechanics by atomic force microscopy (AFM). The obtained mechanical maps were reproducible for cells grown on patterns of the same geometry, revealing pattern-specific subcellular differences. We found that local Young's moduli variations are related to the cell adhesion geometry. Additionally, we detected local changes of cell mechanical properties induced by cytoskeletal drugs. We thus provide a method to quantitatively and systematically investigate cell mechanics and their variations, and present further evidence for a tight relation between cell adhesion and mechanics.

  5. Different cortical mechanisms for spatial vs. feature-based attentional selection in visual working memory

    Directory of Open Access Journals (Sweden)

    Anna Heuer

    2016-08-01

    Full Text Available The limited capacity of visual working memory necessitates attentional mechanisms that selectively update and maintain only the most task-relevant content. Psychophysical experiments have shown that the retroactive selection of memory content can be based on visual properties such as location or shape, but the neural basis for such differential selection is unknown. For example, it is not known if there are different cortical modules specialized for spatial versus feature-based mnemonic attention, in the same way that has been demonstrated for attention to perceptual input. Here, we used transcranial magnetic stimulation (TMS to identify areas in human parietal and occipital cortex involved in the selection of objects from memory based on cues to their location (spatial information or their shape (featural information. We found that TMS over the supramarginal gyrus (SMG selectively facilitated spatial selection, whereas TMS over the lateral occipital cortex selectively enhanced feature-based selection for remembered objects in the contralateral visual field. Thus, different cortical regions are responsible for spatial vs. feature-based selection of working memory representations. Since the same regions are involved in attention to external events, these new findings indicate overlapping mechanisms for attentional control over perceptual input and mnemonic representations.

  6. Use of Mechanical Turk as a MapReduce Framework for Macular OCT Segmentation

    Directory of Open Access Journals (Sweden)

    Aaron Y. Lee

    2016-01-01

    Full Text Available Purpose. To evaluate the feasibility of using Mechanical Turk as a massively parallel platform to perform manual segmentations of macular spectral domain optical coherence tomography (SD-OCT images using a MapReduce framework. Methods. A macular SD-OCT volume of 61 slice images was map-distributed to Amazon Mechanical Turk. Each Human Intelligence Task was set to $0.01 and required the user to draw five lines to outline the sublayers of the retinal OCT image after being shown example images. Each image was submitted twice for segmentation, and interrater reliability was calculated. The interface was created using custom HTML5 and JavaScript code, and data analysis was performed using R. An automated pipeline was developed to handle the map and reduce steps of the framework. Results. More than 93,500 data points were collected using this framework for the 61 images submitted. Pearson’s correlation of interrater reliability was 0.995 (p<0.0001 and coefficient of determination was 0.991. The cost of segmenting the macular volume was $1.21. A total of 22 individual Mechanical Turk users provided segmentations, each completing an average of 5.5 HITs. Each HIT was completed in an average of 4.43 minutes. Conclusions. Amazon Mechanical Turk provides a cost-effective, scalable, high-availability infrastructure for manual segmentation of OCT images.

  7. Visualizing acoustic similarities between emotions in speech: an acoustic map of emotions

    NARCIS (Netherlands)

    Truong, K.P.; Leeuwen, D.A. van

    2007-01-01

    In this paper, we introduce a visual analysis method to assess the discriminability and confusiability between emotions according to automatic emotion classifiers. The degree of acoustic similarities between emotions can be defined in terms of distances that are based on pair-wise emotion

  8. Direct visualization of the subthalamic nucleus and its iron distribution using high-resolution susceptibility mapping

    NARCIS (Netherlands)

    Schäfer, A.; Forstmann, B.U.; Neumann, J.; Wharton, S.; Mietke, A.; Bowtell, R.; Turner, R.

    2012-01-01

    Histological studies have shown a relatively high iron concentration in the subthalamic nucleus (STN). T2- and T2*-weighted sequences have previously been used to visualize the STN in vivo. The phase information of gradient-echo images reflects the magnetic tissue properties more directly, e.g.,

  9. Visualizing MR diffusion tensor fields by dynamic fiber tracking and uncertainty mapping

    NARCIS (Netherlands)

    Ehricke, HH; Klose, U; Grodd, W

    Recent advances in magnetic resonance imaging have provided methods for the acquisition of high-resolution diffusion tensor fields. Their 3D-visualization with streamline-based techniques-called fiber tracking-allow analysis of cerebral white matter tracts for diagnostic, therapeutic as well as

  10. A biomechanical evaluation of visually impaired persons' gait and long-cane mechanics.

    Science.gov (United States)

    Ramsey, V K; Blasch, B B; Kita, A; Johnson, B F

    1999-10-01

    This study was designed to compare selected kinematic components of gait and long cane mechanics between groups of visually impaired travelers. Twenty subjects were placed in Traditional or Modified technique groups according to their long cane traveling technique. Subjects were measured during the following conditions; 1) normal walking (NW), 2) walking while anticipating a simulated drop-off (AD), 3) walking while responding to an audible task (ST) and, 4) walking while anticipating a simulated drop-off and responding to an audible task (STAD). Data were analyzed using a repeated measures analysis of variance (ANOVA) and Pearson's r correlation coefficient. Analyses revealed no differences between groups of travelers. However, significant differences were noted between trials for components of gait velocity, stride length, and hip flexion velocity. These findings may indicate a potentially dangerous alteration in the normal gait cycle of visually impaired travelers when faced with additional attention-demanding tasks while walking.

  11. Visual sensory processing deficits in patients with bipolar disorder revealed through high-density electrical mapping.

    LENUS (Irish Health Repository)

    Yeap, Sherlyn

    2009-11-01

    BACKGROUND: Etiological commonalities are apparent between bipolar disorder and schizophrenia. For example, it is becoming clear that both populations show similar electrophysiological deficits in the auditory domain. Recent studies have also shown robust visual sensory processing deficits in patients with schizophrenia using the event-related potential technique, but this has not been formally tested in those with bipolar disorder. Our goal here was to assess whether early visual sensory processing in patients with bipolar disorder, as indexed by decreased amplitude of the P1 component of the visual evoked potential (VEP), would show a similar deficit to that seen in those with schizophrenia. Since the P1 deficit has already been established as an endophenotype in schizophrenia, a finding of commonality between disorders would raise the possibility that it represents a measure of common genetic liability. METHODS: We visually presented isolated-check stimuli to euthymic patients with a diagnosis of bipolar disorder and age-matched healthy controls within a simple go\\/no-go task and recorded VEPs using high-density (72-channel) electroencephalography. RESULTS: The P1 VEP amplitude was substantially reduced in patients with bipolar disorder, with an effect size of f = 0.56 (large according to Cohen\\'s criteria). LIMITATIONS: Our sample size was relatively small and as such, did not allow for an examination of potential relations between the physiologic measures and clinical measures. CONCLUSION: This reduction in P1 amplitude among patients with bipolar disorder represents a dysfunction in early visual processing that is highly similar to that found repeatedly in patients with schizophrenia and their healthy first-degree relatives. Since the P1 deficit has been related to susceptibility genes for schizophrenia, our results raise the possibility that the deficit may in fact be more broadly related to the development of psychosis and that it merits further

  12. Visual sensory processing deficits in patients with bipolar disorder revealed through high-density electrical mapping.

    Science.gov (United States)

    Yeap, Sherlyn; Kelly, Simon P; Reilly, Richard B; Thakore, Jogin H; Foxe, John J

    2009-11-01

    Etiological commonalities are apparent between bipolar disorder and schizophrenia. For example, it is becoming clear that both populations show similar electrophysiological deficits in the auditory domain. Recent studies have also shown robust visual sensory processing deficits in patients with schizophrenia using the event-related potential technique, but this has not been formally tested in those with bipolar disorder. Our goal here was to assess whether early visual sensory processing in patients with bipolar disorder, as indexed by decreased amplitude of the P1 component of the visual evoked potential (VEP), would show a similar deficit to that seen in those with schizophrenia. Since the P1 deficit has already been established as an endophenotype in schizophrenia, a finding of commonality between disorders would raise the possibility that it represents a measure of common genetic liability. We visually presented isolated-check stimuli to euthymic patients with a diagnosis of bipolar disorder and age-matched healthy controls within a simple go/no-go task and recorded VEPs using high-density (72-channel) electroencephalography. The P1 VEP amplitude was substantially reduced in patients with bipolar disorder, with an effect size of f = 0.56 (large according to Cohen's criteria). Our sample size was relatively small and as such, did not allow for an examination of potential relations between the physiologic measures and clinical measures. This reduction in P1 amplitude among patients with bipolar disorder represents a dysfunction in early visual processing that is highly similar to that found repeatedly in patients with schizophrenia and their healthy first-degree relatives. Since the P1 deficit has been related to susceptibility genes for schizophrenia, our results raise the possibility that the deficit may in fact be more broadly related to the development of psychosis and that it merits further investigation as a candidate endophenotype for bipolar disorder.

  13. Data Maps: A Hypertext Technique for Visualizing, Analyzing and Presenting Qualitative Data.

    Science.gov (United States)

    Horney, Mark

    Making diagrams of the relationships among data is not a new idea: however, the utility of computerized hypertext techniques makes the task more feasible, on a wider scale of data. Data maps using "EntryWay" (a hypertext editing program) were made based on qualitative data from eight different research projects, including: a discourse…

  14. ResistoMap-online visualization of human gut microbiota antibiotic resistome.

    Science.gov (United States)

    Yarygin, Konstantin S; Kovarsky, Boris A; Bibikova, Tatyana S; Melnikov, Damir S; Tyakht, Alexander V; Alexeev, Dmitry G

    2017-07-15

    ResistoMap was implemented using AngularJS, CoffeeScript, D3.js and TopoJSON. The tool is publicly available at http://resistomap.rcpcm.org . yarygin@phystech.edu. Supplementary data are available at Bioinformatics online.

  15. Mapping texts through dimensionality reduction and visualization techniques for interactive exploration of document collections

    Science.gov (United States)

    de Andrade Lopes, Alneu; Minghim, Rosane; Melo, Vinícius; Paulovich, Fernando V.

    2006-01-01

    The current availability of information many times impair the tasks of searching, browsing and analyzing information pertinent to a topic of interest. This paper presents a methodology to create a meaningful graphical representation of documents corpora targeted at supporting exploration of correlated documents. The purpose of such an approach is to produce a map from a document body on a research topic or field based on the analysis of their contents, and similarities amongst articles. The document map is generated, after text pre-processing, by projecting the data in two dimensions using Latent Semantic Indexing. The projection is followed by hierarchical clustering to support sub-area identification. The map can be interactively explored, helping to narrow down the search for relevant articles. Tests were performed using a collection of documents pre-classified into three research subject classes: Case-Based Reasoning, Information Retrieval, and Inductive Logic Programming. The map produced was capable of separating the main areas and approaching documents by their similarity, revealing possible topics, and identifying boundaries between them. The tool can deal with the exploration of inter-topics and intra-topic relationship and is useful in many contexts that need deciding on relevant articles to read, such as scientific research, education, and training.

  16. Images Are Not the (Only) Truth: Brain Mapping, Visual Knowledge, and Iconoclasm.

    Science.gov (United States)

    Beaulieu, Anne

    2002-01-01

    Debates the paradoxical nature of claims about the emerging contributions of functional brain mapping. Examines the various ways that images are deployed and rejected and highlights an approach that provides insight into the current demarcation of imaging. (Contains 68 references.) (DDR)

  17. Second Generation MOSAIC:A Novel Mechanism Based on Reference Database for Map Updating

    Science.gov (United States)

    Hu, G.; Bignone, F.

    2011-08-01

    A totally new automatic workflow mechanism, named Second generation Mosaic module, based on the well-known Pixel Factory system, will be introduced here, which enables existing digital orthoimages and mosaics to be quickly updated. The process extracts all required parameters from the reference database to be able to perform automatic bundle adjustment and radiometric adaptation.In this paper, two examples for both satellite data and aerial data processed based on this mechanism will be presented here and discussed. Finally, the cost reduction will also be analysed according to the real mapping updating project.In a final statement, this paper will present an integrated solution named second generation mosaic module based on the well-known Pixel Factory system which is completely dedicated to fast processing of photogrammetric products Thanks to this integrated hardware and software solution, it is even possible to manage large data volume quickly in order to have precise map updating information as soon as possible after acquisition.

  18. Depth-Resolved Mapping of Tissue Mechanical Properties Using a Novel Optical Approach

    OpenAIRE

    Hajjarian, Zeinab; Nadkarni, Seemantni K.

    2011-01-01

    Progression of most diseases, such as atherosclerosis, cancer, neurodegenerative disease and osteoarthritis is accompanied with drastic changes in biomechanics of tissue. Hence, non-contact and non-invasive technologies for 3-dimensional mapping of tissue biomechanics are invaluable for diagnostic purposes. Laser speckle Microrheology (LSM) is developed in our lab to enable high resolution mechanical evaluation of tissue. To this end, the tissue sample is illuminated by a coherent and focused...

  19. Functional mapping of the human visual cortex with intravoxel incoherent motion MRI.

    Directory of Open Access Journals (Sweden)

    Christian Federau

    Full Text Available Functional imaging with intravoxel incoherent motion (IVIM magnetic resonance imaging (MRI is demonstrated. Images were acquired at 3 Tesla using a standard Stejskal-Tanner diffusion-weighted echo-planar imaging sequence with multiple b-values. Cerebro-spinal fluid signal, which is highly incoherent, was suppressed with an inversion recovery preparation pulse. IVIM microvascular perfusion parameters were calculated according to a two-compartment (vascular and non-vascular diffusion model. The results obtained in 8 healthy human volunteers during visual stimulation are presented. The IVIM blood flow related parameter fD* increased 170% during stimulation in the visual cortex, and 70% in the underlying white matter.

  20. Virtual brain mapping: Meta-analysis and visualization in functional neuroimaging

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup

    automatically model and visualize several studies at once. We model a set of 3-dimensional coordinates by a voxelization step where flexible probability density models such as kernel density estimators produce a voxel-volume representation of a study, allowing us to represent all coordinate data in one single...... Environments or exported as VRML97 and made available on the Internet, see http://hendrix.imm.dtu.dk....

  1. Mapping the Primate Visual System with [2-14C]Deoxyglucose

    Science.gov (United States)

    Macko, Kathleen A.; Jarvis, Charlene D.; Kennedy, Charles; Miyaoka, Mikoto; Shinohara, Mami; Sokoloff, Louis; Mishkin, Mortimer

    1982-10-01

    The [2-14C]deoxyglucose method was used to identify the cerebral areas related to vision in the rhesus monkey (Macaca mulatta). This was achieved by comparing glucose utilization in a visually stimulated with that in a visually deafferented hemisphere. The cortical areas related to vision included the entire expanse of striate, prestriate, and inferior temporal cortex as far forward as the temporal pole, the posterior part of the inferior parietal lobule, and the prearcuate and inferior prefrontal cortex. Subcortically, in addition to the dorsal lateral geniculate nucleus and superficial layers of the superior colliculus, the structures related to vision included large parts of the pulvinar, caudate, putamen, claustrum, and amygdala. These results, which are consonant with a model of visual function that postulates an occipito-temporo-prefrontal pathway for object vision and an occipito-parieto-prefrontal pathway for spatial vision, reveal the full extent of those pathways and identify their points of contact with limbic, striatal, and diencephalic structures.

  2. Visualizing Neuromodulation In Vivo: TANGO-Mapping of Dopamine Signaling Reveals Appeptite Control of Sugar Sensing

    Science.gov (United States)

    Inagaki, Hidehiko K.; de-Leon, Shlomo Ben-Tabou; Wong, Allan M.; Jagadish, Smitha; Ishimoto, Hiroshi; Barnea, Gilad; Kitamoto, Toshihiro; Axel, Richard; Anderson, David J.

    2012-01-01

    SUMMARY Behavior cannot be predicted from a “connectome,” because the brain contains a chemical “map” of neuromodulation superimposed upon its synaptic connectivity map. Neuromodulation changes how neural circuits process information in different states, such as hunger or arousal. Here we describe a novel, genetically based method to map, in an unbiased and brain-wide manner, sites of neuromodulation under different conditions in the Drosophila brain. This method, and genetic perturbations, reveal that the well-known effect of hunger to enhance behavioral sensitivity to sugar is mediated, at least in part, by the release of dopamine onto primary gustatory sensory neurons, which enhances sugar-evoked calcium influx. These data reinforce the concept that sensory neurons constitute an important locus for state-dependent gain-control of behavior, and introduce a new methodology that can be extended to other neuromodulators and model organisms. PMID:22304923

  3. Asymmetrical interhemispheric connections develop in cat visual cortex after early unilateral convergent strabismus: Anatomy, physiology and mechanisms

    Directory of Open Access Journals (Sweden)

    Emmanuel eBui Quoc

    2012-01-01

    Full Text Available In the mammalian primary visual cortex, the corpus callosum contributes to the unification of the visual hemifields that project to the two hemispheres. Its development depends on visual experience. When the latter is abnormal, callosal connections must undergo dramatic anatomical and physiological changes. However, such data are sparse and incomplete. Thus, little is known about the consequences of abnormal postnatal visual experience on the development of callosal connections and their role in unifying representation of the two hemifields. Here, the effects of early unilateral convergent strabismus (a model of abnormal visual experience were fully characterized with respect to the development of the callosal connections in cat visual cortex, an experimental model for humans. Electrophysiological responses and 3D reconstruction of single callosal axons show that abnormally asymmetrical callosal connections develop after unilateral convergent strabismus, resulting from an extension of axonal branches of specific orders in the hemisphere ipsilateral to the deviated eye and a decreased number of nodes and terminals in the other (ipsilateral to the non deviated eye. Furthermore this asymmetrical organization prevents the establishment of a unifying representation of the two visual hemifields. As a general rule, we suggest that crossed and uncrossed retino-geniculo-cortical pathways contribute in succession to the development of the callosal maps in visual cortex.

  4. Comparison of visual and refractive results after transepithelial and mechanical photorefractive keratectomy in myopia.

    Science.gov (United States)

    Yildirim, Yusuf; Olcucu, Onur; Alagoz, Nese; Agca, Alper; Karakucuk, Yalcin; Demirok, Ahmet

    2017-03-27

    To compare postoperative visual outcomes and higher-order aberrations (HOAs) following transepithelial photorefractive keratectomy (t-PRK) and mechanical photorefractive keratectomy (m-PRK). The medical records of patients who underwent photorefractive keratectomy (PRK) were retrospectively evaluated. Forty-five patients were treated with m-PRK, and 45 were treated with t-PRK. Visual acuity, subjective manifest refraction, and corneal topography were analyzed before surgery and 12 months after surgery for both groups. Total HOAs, spherical, coma, and trefoil aberrations were derived from topography data over the 6-mm corneal zone. In the m-PRK group, the mean preoperative spherical equivalence (SE) changed from -3.15 ± 0.70 D preoperatively to -0.24 ± 0.70 D 1 year postoperatively. Likewise, SE decreased from -3.36 ± 0.63 to -0.25 ± 0.63 D in the t-PRK group 1 year after the surgery. The number of eyes within ± 0.50 D of the target refraction was 89% for m-PRK and 87% for t-PRK groups (p = 0.20). Eighty-four percentage of eyes in the t-PRK group and 80% of eyes in the m-PRK group showed an uncorrected distance visual acuity of 20/25 or better (p = 0.24). Total HOAs, spherical aberration, coma, and trefoil aberrations increased in both groups after surgery, but no statistically significant differences were detected postoperatively among the corneal aberrations. t-PRK and m-PRK result in comparable refractive results for the correction of low and moderate myopia. Corneal aberrations induced by t-PRK and m-PRK were similar. Epithelial removal techniques do not affect visual, refractive results, or HOAs in PRK.

  5. A simple, fast, and repeatable survey method for underwater visual 3D benthic mapping and monitoring.

    Science.gov (United States)

    Pizarro, Oscar; Friedman, Ariell; Bryson, Mitch; Williams, Stefan B; Madin, Joshua

    2017-03-01

    Visual 3D reconstruction techniques provide rich ecological and habitat structural information from underwater imagery. However, an unaided swimmer or diver struggles to navigate precisely over larger extents with consistent image overlap needed for visual reconstruction. While underwater robots have demonstrated systematic coverage of areas much larger than the footprint of a single image, access to suitable robotic systems is limited and requires specialized operators. Furthermore, robots are poor at navigating hydrodynamic habitats such as shallow coral reefs. We present a simple approach that constrains the motion of a swimmer using a line unwinding from a fixed central drum. The resulting motion is the involute of a circle, a spiral-like path with constant spacing between revolutions. We test this survey method at a broad range of habitats and hydrodynamic conditions encircling Lizard Island in the Great Barrier Reef, Australia. The approach generates fast, structured, repeatable, and large-extent surveys (~110 m2 in 15 min) that can be performed with two people and are superior to the commonly used "mow the lawn" method. The amount of image overlap is a design parameter, allowing for surveys that can then be reliably used in an automated processing pipeline to generate 3D reconstructions, orthographically projected mosaics, and structural complexity indices. The individual images or full mosaics can also be labeled for benthic diversity and cover estimates. The survey method we present can serve as a standard approach to repeatedly collecting underwater imagery for high-resolution 2D mosaics and 3D reconstructions covering spatial extents much larger than a single image footprint without requiring sophisticated robotic systems or lengthy deployment of visual guides. As such, it opens up cost-effective novel observations to inform studies relating habitat structure to ecological processes and biodiversity at scales and spatial resolutions not readily

  6. Direct visualization of glutamate transporter elevator mechanism by high-speed AFM.

    Science.gov (United States)

    Ruan, Yi; Miyagi, Atsushi; Wang, Xiaoyu; Chami, Mohamed; Boudker, Olga; Scheuring, Simon

    2017-02-14

    Glutamate transporters are essential for recovery of the neurotransmitter glutamate from the synaptic cleft. Crystal structures in the outward- and inward-facing conformations of a glutamate transporter homolog from archaebacterium Pyrococcus horikoshii, sodium/aspartate symporter GltPh, suggested the molecular basis of the transporter cycle. However, dynamic studies of the transport mechanism have been sparse and indirect. Here we present high-speed atomic force microscopy (HS-AFM) observations of membrane-reconstituted GltPh at work. HS-AFM movies provide unprecedented real-space and real-time visualization of the transport dynamics. Our results show transport mediated by large amplitude 1.85-nm "elevator" movements of the transport domains consistent with previous crystallographic and spectroscopic studies. Elevator dynamics occur in the absence and presence of sodium ions and aspartate, but stall in sodium alone, providing a direct visualization of the ion and substrate symport mechanism. We show unambiguously that individual protomers within the trimeric transporter function fully independently.

  7. Synaptic Mechanisms of Activity-Dependent Remodeling in Visual Cortex during Monocular Deprivation

    Directory of Open Access Journals (Sweden)

    Cynthia D. Rittenhouse

    2009-01-01

    Full Text Available It has long been appreciated that in the visual cortex, particularly within a postnatal critical period for experience-dependent plasticity, the closure of one eye results in a shift in the responsiveness of cortical cells toward the experienced eye. While the functional aspects of this ocular dominance shift have been studied for many decades, their cortical substrates and synaptic mechanisms remain elusive. Nonetheless, it is becoming increasingly clear that ocular dominance plasticity is a complex phenomenon that appears to have an early and a late component. Early during monocular deprivation, deprived eye cortical synapses depress, while later during the deprivation open eye synapses potentiate. Here we review current literature on the cortical mechanisms of activity-dependent plasticity in the visual system during the critical period. These studies shed light on the role of activity in shaping neuronal structure and function in general and can lead to insights regarding how learning is acquired and maintained at the neuronal level during normal and pathological brain development.

  8. From the Shadow to the Map: Visualizing Rio de Janeiro’s Favelas

    Directory of Open Access Journals (Sweden)

    Débora Póvoa

    2017-06-01

    Full Text Available Film Review Essay In the Shadow of the Hill, by Dan Jackson. Future Paradigm Pictures, 2016. Fighting for Peace, by Joost van der Valk and Mags Gavan. Red Rebel Films, 2015. City of God: 10 Years Later, by Cavi Borges and Luciano Vidigal. Brazil: Berny Filmes / Canal Brasil / Cavideo Produções / Cinema Nosso / Link Digital / Nós do Morro, 2013. Beyond the Map, https://beyondthemap.withgoogle.com/. Collaboration between Google Arts & Culture and AfroReggae, 2016.

  9. Robotic palpation-based mechanical property mapping for diagnosis of prostate cancer.

    Science.gov (United States)

    Ahn, Bummo; Lorenzo, Enrique Ian S; Rha, Koon Ho; Kim, Hyung Joo; Kim, Jung

    2011-05-01

    The aim of this study was to estimate the mechanical properties (elasticity) of normal and cancer prostate tissues and to develop a tissue elasticity map for the diagnosis and localization of prostate cancer. A total of 735 sites from 35 radical prostatectomy specimens were used in the experiments using a robotic palpation system, and the elasticities of the specimens were estimated by a tissue characterization algorithm. The estimated elasticities from 21 regions were separated into normal and cancer tissues using the pathological information, and a tissue elasticity map was developed using numerical functions and a nonlinear surface-fitting method. The mean elastic moduli of the normal and cancer tissues were 15.25 ± 5.88 and 28.80 ± 11.20 kPa, respectively. The base region had the highest elasticity, followed by the medial and apex regions. These results demonstrated the ability to separate the cancer tissue from the normal tissue based on its elastic modulus. The tissue elasticity mapping was carried out using the estimated elasticity and nonlinear surface fitting. The proposed map showed the elasticity and was used to estimate the elastic modulus of the prostate at any given region. Tissue elasticity may be an important indicator of prostate cancer because the pathologic changes alter the tissue properties, including cell integrity and intercellular matrix. This work provides quantitative and objective information for the diagnosis of prostate cancer. In addition, these results may have implications for the localization of prostate cancers.

  10. Genetic fine-mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci

    Science.gov (United States)

    Mahajan, Anubha; Locke, Adam; Rayner, N William; Robertson, Neil; Scott, Robert A; Prokopenko, Inga; Scott, Laura J; Green, Todd; Sparso, Thomas; Thuillier, Dorothee; Yengo, Loic; Grallert, Harald; Wahl, Simone; Frånberg, Mattias; Strawbridge, Rona J; Kestler, Hans; Chheda, Himanshu; Eisele, Lewin; Gustafsson, Stefan; Steinthorsdottir, Valgerdur; Thorleifsson, Gudmar; Qi, Lu; Karssen, Lennart C; van Leeuwen, Elisabeth M; Willems, Sara M; Li, Man; Chen, Han; Fuchsberger, Christian; Kwan, Phoenix; Ma, Clement; Linderman, Michael; Lu, Yingchang; Thomsen, Soren K; Rundle, Jana K; Beer, Nicola L; van de Bunt, Martijn; Chalisey, Anil; Kang, Hyun Min; Voight, Benjamin F; Abecasis, Goncalo R; Almgren, Peter; Baldassarre, Damiano; Balkau, Beverley; Benediktsson, Rafn; Blüher, Matthias; Boeing, Heiner; Bonnycastle, Lori L; Borringer, Erwin P; Burtt, Noël P; Carey, Jason; Charpentier, Guillaume; Chines, Peter S; Cornelis, Marilyn C; Couper, David J; Crenshaw, Andrew T; van Dam, Rob M; Doney, Alex SF; Dorkhan, Mozhgan; Edkins, Sarah; Eriksson, Johan G; Esko, Tonu; Eury, Elodie; Fadista, João; Flannick, Jason; Fontanillas, Pierre; Fox, Caroline; Franks, Paul W; Gertow, Karl; Gieger, Christian; Gigante, Bruna; Gottesman, Omri; Grant, George B; Grarup, Niels; Groves, Christopher J; Hassinen, Maija; Have, Christian T; Herder, Christian; Holmen, Oddgeir L; Hreidarsson, Astradur B; Humphries, Steve E; Hunter, David J; Jackson, Anne U; Jonsson, Anna; Jørgensen, Marit E; Jørgensen, Torben; Kerrison, Nicola D; Kinnunen, Leena; Klopp, Norman; Kong, Augustine; Kovacs, Peter; Kraft, Peter; Kravic, Jasmina; Langford, Cordelia; Leander, Karin; Liang, Liming; Lichtner, Peter; Lindgren, Cecilia M; Lindholm, Eero; Linneberg, Allan; Liu, Ching-Ti; Lobbens, Stéphane; Luan, Jian’an; Lyssenko, Valeriya; Männistö, Satu; McLeod, Olga; Meyer, Julia; Mihailov, Evelin; Mirza, Ghazala; Mühleisen, Thomas W; Müller-Nurasyid, Martina; Navarro, Carmen; Nöthen, Markus M; Oskolkov, Nikolay N; Owen, Katharine R; Palli, Domenico; Pechlivanis, Sonali; Perry, John RB; Platou, Carl GP; Roden, Michael; Ruderfer, Douglas; Rybin, Denis; van der Schouw, Yvonne T; Sennblad, Bengt; Sigurðsson, Gunnar; Stančáková, Alena; Steinbach, Gerald; Storm, Petter; Strauch, Konstantin; Stringham, Heather M; Sun, Qi; Thorand, Barbara; Tikkanen, Emmi; Tonjes, Anke; Trakalo, Joseph; Tremoli, Elena; Tuomi, Tiinamaija; Wennauer, Roman; Wood, Andrew R; Zeggini, Eleftheria; Dunham, Ian; Birney, Ewan; Pasquali, Lorenzo; Ferrer, Jorge; Loos, Ruth JF; Dupuis, Josée; Florez, Jose C; Boerwinkle, Eric; Pankow, James S; van Duijn, Cornelia; Sijbrands, Eric; Meigs, James B; Hu, Frank B; Thorsteinsdottir, Unnur; Stefansson, Kari; Lakka, Timo A; Rauramaa, Rainer; Stumvoll, Michael; Pedersen, Nancy L; Lind, Lars; Keinanen-Kiukaanniemi, Sirkka M; Korpi-Hyövälti, Eeva; Saaristo, Timo E; Saltevo, Juha; Kuusisto, Johanna; Laakso, Markku; Metspalu, Andres; Erbel, Raimund; Jöckel, Karl-Heinz; Moebus, Susanne; Ripatti, Samuli; Salomaa, Veikko; Ingelsson, Erik; Boehm, Bernhard O; Bergman, Richard N; Collins, Francis S; Mohlke, Karen L; Koistinen, Heikki; Tuomilehto, Jaakko; Hveem, Kristian; Njølstad, Inger; Deloukas, Panagiotis; Donnelly, Peter J; Frayling, Timothy M; Hattersley, Andrew T; de Faire, Ulf; Hamsten, Anders; Illig, Thomas; Peters, Annette; Cauchi, Stephane; Sladek, Rob; Froguel, Philippe; Hansen, Torben; Pedersen, Oluf; Morris, Andrew D; Palmer, Collin NA; Kathiresan, Sekar; Melander, Olle; Nilsson, Peter M; Groop, Leif C; Barroso, Inês; Langenberg, Claudia; Wareham, Nicholas J; O’Callaghan, Christopher A; Gloyn, Anna L; Altshuler, David; Boehnke, Michael; Teslovich, Tanya M; McCarthy, Mark I; Morris, Andrew P

    2015-01-01

    We performed fine-mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in/near KCNQ1. “Credible sets” of variants most likely to drive each distinct signal mapped predominantly to non-coding sequence, implying that T2D association is mediated through gene regulation. Credible set variants were enriched for overlap with FOXA2 chromatin immunoprecipitation binding sites in human islet and liver cells, including at MTNR1B, where fine-mapping implicated rs10830963 as driving T2D association. We confirmed that this T2D-risk allele increases FOXA2-bound enhancer activity in islet- and liver-derived cells. We observed allele-specific differences in NEUROD1 binding in islet-derived cells, consistent with evidence that the T2D-risk allele increases islet MTNR1B expression. Our study demonstrates how integration of genetic and genomic information can define molecular mechanisms through which variants underlying association signals exert their effects on disease. PMID:26551672

  11. Retrieval interval mapping: a tool to visualize the impact of the spectral retrieval range on differential optical absorption spectroscopy evaluations

    Directory of Open Access Journals (Sweden)

    L. Vogel

    2013-02-01

    Full Text Available Remote sensing via differential optical absorption spectroscopy (DOAS has become a standard technique to identify and quantify trace gases in the atmosphere. Due to the wide range of measurement conditions, atmospheric compositions and instruments used, a specific challenge of a DOAS retrieval is to optimize the retrieval parameters for each specific case and particular trace gas of interest. Of these parameters, the retrieval wavelength range is one of the most important ones. Although for many trace gases the overall dependence of common DOAS retrieval on the evaluation wavelength interval is known, a systematic approach for finding the optimal retrieval wavelength range and quantitative assessment is missing. Here we present a novel tool to visualize the effect of different evaluation wavelength ranges. It is based on mapping retrieved column densities in the retrieval wavelength space and thus visualizing the consequences of different choices of spectral retrieval ranges caused by slightly erroneous absorption cross sections, cross correlations and instrumental features. Based on the information gathered, an optimal retrieval wavelength range may be determined systematically.

    The technique is demonstrated using examples of a theoretical study of BrO retrievals for stratospheric BrO and BrO measurements in volcanic plumes. However, due to the general nature of the tool, it is applicable to any type of DOAS retrieval (active or passive.

  12. Assessment of the visual landscape impact and dominance of wind tubines in Austria using weighted viewshed maps

    Science.gov (United States)

    Schauppenlehner, Thomas; Salak, Boris; Scherhaufer, Patrick; Höltinger, Stefan; Schmidt, Johannes

    2017-04-01

    Due to efficiency reasons and broadly availability of wind, wind energy is in focus of strategies regarding the expansion of renewable energy and energy transition policies. Nevertheless, the dimensions of the wind turbines and rotating dynamics have a significant impact on the landscape scenery and recreation as well as tourism activities. This often leads to local opposition against wind energy projects and is a major criterion regarding the acceptance of wind energy. In the project TransWind, the social acceptance of wind energy is surveyed on the basis of different development scenarios for Austria. Therefore, a GIS-based viewshed indicator was developed to assess the visual impact of different development scenarios as well as the current situation using weighted - regarding distance, amount and masking - viewshed analysis. This weighted viewshed maps for Austria allows a comprehensive evaluation of existing and potential wind energy sites regarding dominance and visual impact and can contribute to the spatial development process of wind energy site. Different regions can be compared and repowering strategies can be evaluated. Due to the large project area, data resolutions, generalized assumptions (e.g. tree heights) and missing data (e.g. solitary trees, small hedges) at local level further analysis are necessary but it supports the assessment of large-scale development scenarios can be identified.

  13. Neuro-anatomical dissections of unilateral visual neglect symptoms: ALE meta-analysis of lesion-symptom mapping

    Directory of Open Access Journals (Sweden)

    Magdalena eChechlacz

    2012-08-01

    Full Text Available Unilateral visual neglect is commonly defined as impaired ability to attend to stimuli presented on the side of visual space contralateral to the brain lesion. However, behavioural analyses indicate that different neglect symptoms can dissociate. The neuroanatomy of the syndrome has been hotly debated. Some groups have argued that the syndrome is linked to posterior parietal cortex lesions, while others report damage within regions including the superior temporal gyrus, insula and basal ganglia. Several recent neuroimaging studies provide evidence that heterogeneity in the behavioural symptoms of neglect can be matched by variations in the brain lesions, and that some of the discrepancies across earlier findings might have resulted from the use of different neuropsychological tests and/or varied measures within the same task for diagnosing neglect. In this paper, we review the evidence for dissociations between both the symptoms and the neural substrates of unilateral visual neglect, drawing on ALE (anatomic likelihood estimation meta-analyses of lesion symptom mapping studies. Specifically, we examine dissociations between neglect symptoms associated with impaired control of attention across space (in an egocentric frame of reference and within objects (in an allocentric frame of reference. Results of ALE-meta analyses indicated that, while egocentric symptoms are associated with more anterior cortical damage and damage within sub-cortical structures, more posterior lesions are associated with allocentric symptoms. Furthermore, there was high concurrence in deficits associated with white matter lesions supporting a disconnection account of the syndrome. Using this evidence we argue that different forms of neglect link to both distinct and common patterns of grey and white matter lesions. The findings are discussed in terms of functional accounts of neglect and theoretical models based on computational studies of both normal and impaired

  14. Glucose Metabolic Profile by Visual Assessment Combined with Statistical Parametric Mapping Analysis in Pediatric Patients with Epilepsy.

    Science.gov (United States)

    Zhu, Yuankai; Feng, Jianhua; Wu, Shuang; Hou, Haifeng; Ji, Jianfeng; Zhang, Kai; Chen, Qing; Chen, Lin; Cheng, Haiying; Gao, Liuyan; Chen, Zexin; Zhang, Hong; Tian, Mei

    2017-08-01

    PET with 18 F-FDG has been used for presurgical localization of epileptogenic foci; however, in nonsurgical patients, the correlation between cerebral glucose metabolism and clinical severity has not been fully understood. The aim of this study was to evaluate the glucose metabolic profile using 18 F-FDG PET/CT imaging in patients with epilepsy. Methods: One hundred pediatric epilepsy patients who underwent 18 F-FDG PET/CT, MRI, and electroencephalography examinations were included. Fifteen age-matched controls were also included. 18 F-FDG PET images were analyzed by visual assessment combined with statistical parametric mapping (SPM) analysis. The absolute asymmetry index (|AI|) was calculated in patients with regional abnormal glucose metabolism. Results: Visual assessment combined with SPM analysis of 18 F-FDG PET images detected more patients with abnormal glucose metabolism than visual assessment only. The |AI| significantly positively correlated with seizure frequency ( P glucose metabolism. The only significant contributing variable to the |AI| was the time since last seizure, in patients both with hypometabolism ( P = 0.001) and with hypermetabolism ( P = 0.005). For patients with either hypometabolism ( P glucose metabolic profiles in nonsurgical epilepsy patients. |AI| might be used for evaluation of clinical severity and progress in these patients. Patients with a prolonged period of seizure freedom may have more subtle (or no) metabolic abnormalities on PET. The clinical value of PET might be enhanced by timing the scan closer to clinical seizures. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

  15. Time-to-contact maps for navigation with a low resolution visual prosthesis.

    Science.gov (United States)

    McCarthy, Chris; Barnes, Nick

    2012-01-01

    The perception of independently moving objects in the scene is an important capability for prosthetic vision, but is impeded by the limited resolution and dynamic range of current and near-term retinal prostheses. We propose a novel, biologically-inspired visual representation for prosthetic vision based on the recovery of time-to-contact (τ) with surfaces in the scene. The representation directly encodes the extent of motion towards the observer, placing greatest emphasis on objects posing an imminent threat of collision. Our results suggest the proposed τ-based representation may facilitate earlier perception of incoming objects, and provide clearer distinction between moving objects and the static structure of the scene compared with intensity and depth-based scene representations.

  16. FMRI language mapping in children: a panel of language tasks using visual and auditory stimulation without reading or metalinguistic requirements.

    Science.gov (United States)

    de Guibert, Clément; Maumet, Camille; Ferré, Jean-Christophe; Jannin, Pierre; Biraben, Arnaud; Allaire, Catherine; Barillot, Christian; Le Rumeur, Elisabeth

    2010-06-01

    In the context of presurgical mapping or investigation of neurological and developmental disorders in children, language fMRI raises the issue of the design of a tasks panel achievable by young disordered children. Most language tasks shown to be efficient with healthy children require metalinguistic or reading abilities, therefore adding attentional, cognitive and academic constraints that may be problematic in this context. This study experimented a panel of four language tasks that did not require high attentional skills, reading, or metalinguistic abilities. Two reference tasks involving auditory stimulation (words generation from category, "category"; auditory responsive naming, "definition") were compared with two new tasks involving visual stimulation. These later were designed to tap spontaneous phonological production, in which the names of pictures to be named involve a phonological difference (e.g. in French poule/boule/moule; "phon-diff") or change of segmentation (e.g. in French car/car-te/car-t-on; "phon-seg"). Eighteen healthy children participated (mean age: 12.7+/-3 years). Data processing involved normalizing the data via a matched pairs pediatric template, and inter-task and region of interest analyses with laterality assessment. The reference tasks predominantly activated the left frontal and temporal core language regions, respectively. The new tasks activated these two regions simultaneously, more strongly for the phon-seg task. The union and intersection of all tasks provided more sensitive or specific maps. The study demonstrates that both reference and new tasks highlight core language regions in children, and that the latter are useful for the mapping of spontaneous phonological processing. The use of several different tasks may improve the sensitivity and specificity of fMRI. Copyright 2010 Elsevier Inc. All rights reserved.

  17. In vivo visualization using MRI T2 mapping of induced osteochondrosis and osteochondritis dissecans lesions in goats undergoing controlled exercise.

    Science.gov (United States)

    Tóth, Ferenc; David, Frédéric H; LaFond, Elizabeth; Wang, Luning; Ellermann, Jutta M; Carlson, Cathy S

    2017-04-01

    In vivo visualization of subclinical osteochondrosis (OC) lesions, characterized by necrosis of epiphyseal growth cartilage, is necessary to clarify the pathogenesis of this disease. Hence, our objectives were to demonstrate induced necrosis of the epiphyseal cartilage in vivo using MRI and to monitor progression or resolution of resulting lesions. We also aimed to improve the goat model of OC by introducing controlled exercise. Vascular supply to the epiphyseal cartilage was surgically interrupted in four 5-day-old goats to induce ischemic cartilage necrosis in a medial femoral condyle. Starting 3 weeks postoperatively, goats underwent daily controlled exercise until euthanasia at 6, 10, 11 (n = 2) weeks postoperatively. T2 maps of operated and control femora were obtained in vivo at 3 (n = 4), 6 (n = 4), 9 (n = 3), and 11 (n = 2) weeks postoperatively using a 3 T MR scanner. In vivo MRI findings were validated against MRI results obtained ex vivo at 9.4 T in three goats and compared to histological results in all goats. Surgical interruption of the vascular supply caused ischemic cartilage necrosis in three out of four goats. T2 maps obtained in vivo at 3 T identified regions of increased relaxation time consistent with discrete areas of cartilage necrosis 3-11 weeks postoperatively and demonstrated delayed progression of the ossification front at 9 (n = 1) and 11 (n = 2) weeks postoperatively. In vivo MRI findings were confirmed by ex vivo MRI at 9.4 T and by histology. Identification of cartilage necrosis in clinical patients in the early stages of OC using T2 maps may provide valuable insight into the pathogenesis of this condition. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:868-875, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Short-term retention of visual information: Evidence in support of feature-based attention as an underlying mechanism.

    Science.gov (United States)

    Sneve, Markus H; Sreenivasan, Kartik K; Alnæs, Dag; Endestad, Tor; Magnussen, Svein

    2015-01-01

    Retention of features in visual short-term memory (VSTM) involves maintenance of sensory traces in early visual cortex. However, the mechanism through which this is accomplished is not known. Here, we formulate specific hypotheses derived from studies on feature-based attention to test the prediction that visual cortex is recruited by attentional mechanisms during VSTM of low-level features. Functional magnetic resonance imaging (fMRI) of human visual areas revealed that neural populations coding for task-irrelevant feature information are suppressed during maintenance of detailed spatial frequency memory representations. The narrow spectral extent of this suppression agrees well with known effects of feature-based attention. Additionally, analyses of effective connectivity during maintenance between retinotopic areas in visual cortex show that the observed highlighting of task-relevant parts of the feature spectrum originates in V4, a visual area strongly connected with higher-level control regions and known to convey top-down influence to earlier visual areas during attentional tasks. In line with this property of V4 during attentional operations, we demonstrate that modulations of earlier visual areas during memory maintenance have behavioral consequences, and that these modulations are a result of influences from V4. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. SMALL URBAN GREENERY: MAPPING AND VISUAL ANALYSIS IN KYŌJIMA-SANCHŌME

    Directory of Open Access Journals (Sweden)

    Jorge Almazán

    2012-03-01

    Full Text Available This paper illustrates the practice of maintaining small greenery in a typical high-density, low-rise district in Tokyo through extensive mapping and systematic photographic analysis of vertical green coverage. Overlooked by statistics based on aerial photography, this paper describes small greenery and the way in which it improves urban scenery. As more cities are planning to increase their green surface, this paper aims to bring attention to the potential role of environmental and social sustainability played by small-scale vegetation. Such greenery, spontaneously cultivated by residents, not only contributes to embellishing the streets, but also serves as a social device to personalize and subtly characterize territories, while expressing the creativity and cohesion of the community.

  20. Topographical mapping and mechanical pain sensitivity of myofascial trigger points in the infraspinatus muscle.

    Science.gov (United States)

    Ge, Hong-You; Fernández-de-Las-Peñas, César; Madeleine, Pascal; Arendt-Nielsen, Lars

    2008-10-01

    To screen for the presence of latent and active myofascial trigger points (MTrPs) in patients with unilateral shoulder and arm pain and perform topographical mapping of mechanical pain sensitivity bilaterally in the infraspinatus muscles. Nineteen patients with unilateral musculoskeletal shoulder pain participated in the study. The area overlying the infraspinatus on each side was divided into 10 adjacent sub-areas of 1cm(2), corresponding to the area of a pressure algometer probe. Pressure pain threshold (PPT) was measured in each sub-area bilaterally in the infraspinatus muscles. Following PPT measurement, an acupuncture needle was inserted into each sub-area five times in different directions in order to induce local twitch response and/or referred pain. A significantly lower PPT level in the infraspinatus muscle was detected on the painful side compared with the non-painful side (P=0.001). PPT at midfiber region of the infraspinatus muscles was lower than that at other muscle parts (Pactive MTrPs were found in the infraspinatus muscle on the painful side and there were also multiple latent MTrPs bilaterally in the infraspinatus muscles. PPT at active MTrPs was much lower than the latent MTrPs and again lower than the non-MTrPs. There exists bilateral mechanical hyperalgesia in patients with unilateral shoulder pain. Further, the association of multiple active MTrPs with unilateral shoulder pain and the heterogeneity of mechanical pain sensitivity distribution suggest a crucial role of peripheral sensitization in chronic myofascial pain conditions. Additionally, the locations of MTrPs identified with dry needling correspond well to PPT topographical mapping, suggesting that dry needling and PPT topographical mapping are sensitive techniques in the identification of MTrPs.

  1. Characterization of Aortic Valve Closure Artifact During Outflow Tract Mapping: Correlation With Hemodynamics and Mechanical Valves.

    Science.gov (United States)

    Romero, Jorge; Ajijola, Olujimi; Shivkumar, Kalyanam; Tung, Roderick

    2017-06-01

    Premature ventricular contractions originating in the left ventricle outflow tract represent a significant subgroup of patients referred for catheter ablation. Mechanical artifacts from aortic valve leaflet motion may be observed during mapping, although the incidence and characteristics have not been reported. Twenty-eight consecutive patients with left ventricle outflow tract premature ventricular contraction were included. Electric signals recorded on the ablation catheter not coincident with atrial or ventricular depolarization were analyzed on the recording system. Correlation with invasive hemodynamic aortic pressure tracings was performed. Additionally, 4 patients with mechanical aortic valves, who underwent scar-related ventricular tachycardia ablation, were analyzed to correlate the timing of the observed artifacts with native aortic valves. Aortic valve artifact was observed while mapping within the coronary cusps in 11 patients (39%; 73% men; age, 41±25 years; left ventricular ejection fraction 49±16%) with high incidence from the left coronary cusp. This artifact was consistently observed with timing coincident with the terminal portion of the T wave. The average interval between the end of the T wave and the aortic valve artifact was 19±37 ms. The duration of the aortic valve artifact was 39±8 ms with amplitude of 0.12±0.07 mV (range, 0.06-0.36 mV). In patients referred for left ventricle outflow tract premature ventricular contraction ablation, an aortic valve closure artifact is observed in up to one third of cases during mapping within the aortic cusps. The timing of this artifact correlates with invasive hemodynamics and mechanical aortic valve artifacts. Recognition of this physiological phenomenon is useful when assigning near-field activation. © 2017 American Heart Association, Inc.

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

    Science.gov (United States)

    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 eyetracking.upol.cz/scangraph"target="_blank">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).

  3. Concept Mapping.

    Science.gov (United States)

    Callison, Daniel

    2001-01-01

    Explains concept mapping as a heuristic device that is helpful in visualizing the relationships between and among ideas. Highlights include how to begin a map; brainstorming; map applications, including document or information summaries and writing composition; and mind mapping to strengthen note-taking. (LRW)

  4. Extended theory of harmonic maps connects general relativity to chaos and quantum mechanism

    Science.gov (United States)

    Ren, Gang; Duan, Yi-Shi

    2017-10-01

    General relativity and quantum mechanism are two separate rules of modern physics explaining how nature works. Both theories are accurate, but the direct connection between two theories was not yet clarified. Recently, researchers blur the line between classical and quantum physics by connecting chaos and entanglement. Here, we showed the early reported extended HM theory that included the general relativity can also be used to recover the classic chaos equations and even the Schrodinger equation in quantum physics, suggesting the extended theory of harmonic maps may act as a universal theory of physics.

  5. VISA: AN AUTOMATIC AWARE AND VISUAL AIDS MECHANISM FOR IMPROVING THE CORRECT USE OF GEOSPATIAL DATA

    Directory of Open Access Journals (Sweden)

    J. H. Hong

    2016-06-01

    Full Text Available With the fast growth of internet-based sharing mechanism and OpenGIS technology, users nowadays enjoy the luxury to quickly locate and access a variety of geospatial data for the tasks at hands. While this sharing innovation tremendously expand the possibility of application and reduce the development cost, users nevertheless have to deal with all kinds of “differences” implicitly hidden behind the acquired georesources. We argue the next generation of GIS-based environment, regardless internet-based or not, must have built-in knowledge to automatically and correctly assess the fitness of data use and present the analyzed results to users in an intuitive and meaningful way. The VISA approach proposed in this paper refer to four different types of visual aids that can be respectively used for addressing analyzed results, namely, virtual layer, informative window, symbol transformation and augmented TOC. The VISA-enabled interface works in an automatic-aware fashion, where the standardized metadata serve as the known facts about the selected geospatial resources, algorithms for analyzing the differences of temporality and quality of the geospatial resources were designed and the transformation of analyzed results into visual aids were automatically executed. It successfully presents a new way for bridging the communication gaps between systems and users. GIS has been long seen as a powerful integration tool, but its achievements would be highly restricted if it fails to provide a friendly and correct working platform.

  6. Visa: AN Automatic Aware and Visual Aids Mechanism for Improving the Correct Use of Geospatial Data

    Science.gov (United States)

    Hong, J. H.; Su, Y. T.

    2016-06-01

    With the fast growth of internet-based sharing mechanism and OpenGIS technology, users nowadays enjoy the luxury to quickly locate and access a variety of geospatial data for the tasks at hands. While this sharing innovation tremendously expand the possibility of application and reduce the development cost, users nevertheless have to deal with all kinds of "differences" implicitly hidden behind the acquired georesources. We argue the next generation of GIS-based environment, regardless internet-based or not, must have built-in knowledge to automatically and correctly assess the fitness of data use and present the analyzed results to users in an intuitive and meaningful way. The VISA approach proposed in this paper refer to four different types of visual aids that can be respectively used for addressing analyzed results, namely, virtual layer, informative window, symbol transformation and augmented TOC. The VISA-enabled interface works in an automatic-aware fashion, where the standardized metadata serve as the known facts about the selected geospatial resources, algorithms for analyzing the differences of temporality and quality of the geospatial resources were designed and the transformation of analyzed results into visual aids were automatically executed. It successfully presents a new way for bridging the communication gaps between systems and users. GIS has been long seen as a powerful integration tool, but its achievements would be highly restricted if it fails to provide a friendly and correct working platform.

  7. Visual diet versus associative learning as mechanisms of change in body size preferences.

    Directory of Open Access Journals (Sweden)

    Lynda G Boothroyd

    Full Text Available Systematic differences between populations in their preferences for body size may arise as a result of an adaptive 'prepared learning' mechanism, whereby cues to health or status in the local population are internalized and affect body preferences. Alternatively, differences between populations may reflect their 'visual diet' as a cognitive byproduct of mere exposure. Here we test the relative importance of these two explanations for variation in body preferences. Two studies were conducted where female observers were exposed to pictures of high or low BMI women which were either aspirational (healthy, attractive models in high status clothes or non-aspirational (eating disordered patients in grey leotards, or to combinations thereof, in order to manipulate their body-weight preferences which were tested at baseline and at post-test. Overall, results showed good support for visual diet effects (seeing a string of small or large bodies resulted in a change from pre- to post-test whether the bodies were aspirational or not and also some support for the associative learning explanation (exposure to aspirational images of overweight women induced a towards preferring larger bodies, even when accompanied by equal exposure to lower weight bodies in the non-aspirational category. Thus, both influences may act in parallel.

  8. Visualizing Mars Using Virtual Reality: A State of the Art Mapping Technique Used on Mars Pathfinder

    Science.gov (United States)

    Stoker, C.; Zbinden, E.; Blackmon, T.; Nguyen, L.

    1999-01-01

    We describe an interactive terrain visualization system which rapidly generates and interactively displays photorealistic three-dimensional (3-D) models produced from stereo images. This product, first demonstrated in Mars Pathfinder, is interactive, 3-D, and can be viewed in an immersive display which qualifies it for the name Virtual Reality (VR). The use of this technology on Mars Pathfinder was the first use of VR for geologic analysis. A primary benefit of using VR to display geologic information is that it provides an improved perception of depth and spatial layout of the remote site. The VR aspect of the display allows an operator to move freely in the environment, unconstrained by the physical limitations of the perspective from which the data were acquired. Virtual Reality offers a way to archive and retrieve information in a way that is intuitively obvious. Combining VR models with stereo display systems can give the user a sense of presence at the remote location. The capability, to interactively perform measurements from within the VR model offers unprecedented ease in performing operations that are normally time consuming and difficult using other techniques. Thus, Virtual Reality can be a powerful a cartographic tool. Additional information is contained in the original extended abstract.

  9. CheS-Mapper - Chemical Space Mapping and Visualization in 3D

    Directory of Open Access Journals (Sweden)

    Gütlein Martin

    2012-03-01

    Full Text Available Abstract Analyzing chemical datasets is a challenging task for scientific researchers in the field of chemoinformatics. It is important, yet difficult to understand the relationship between the structure of chemical compounds, their physico-chemical properties, and biological or toxic effects. To that respect, visualization tools can help to better comprehend the underlying correlations. Our recently developed 3D molecular viewer CheS-Mapper (Chemical Space Mapper divides large datasets into clusters of similar compounds and consequently arranges them in 3D space, such that their spatial proximity reflects their similarity. The user can indirectly determine similarity, by selecting which features to employ in the process. The tool can use and calculate different kind of features, like structural fragments as well as quantitative chemical descriptors. These features can be highlighted within CheS-Mapper, which aids the chemist to better understand patterns and regularities and relate the observations to established scientific knowledge. As a final function, the tool can also be used to select and export specific subsets of a given dataset for further analysis.

  10. A Preliminary Study on the Use of Mind Mapping as a Visual-Learning Strategy in General Education Science Classes for Arabic Speakers in the United Arab Emirates

    Science.gov (United States)

    Wilson, Kenesha; Copeland-Solas, Eddia; Guthrie-Dixon, Natalie

    2016-01-01

    Mind mapping was introduced as a culturally relevant pedagogy aimed at enhancing the teaching and learning experience in a general education, Environmental Science class for mostly Emirati English Language Learners (ELL). Anecdotal evidence suggests that the students are very artistic and visual and enjoy group-based activities. It was decided to…

  11. Velocity Mapping Toolbox (VMT): a processing and visualization suite for moving-vessel ADCP measurements

    Science.gov (United States)

    Jackson, R.; Parsons, D. R.; Czuba, J. A.; Mueller, D. S.; Rhoads, B. L.; Engel, F.; Oberg, K. A.; Best, J. L.; Johnson, K. K.; Riley, J. D.

    2011-12-01

    In addition to their common application to measurement of discharge in rivers, acoustic Doppler current profilers (ADCP) provide valuable hydrodynamic data required for understanding geomorphic and fluvial processes. The increasing use of ADCPs to explore the characteristics of complex natural flows has led to a need for standardized post-processing methods for managing, analyzing, and displaying three-dimensional velocity data. Thus far, no standard analytical technique exists for averaging velocity data from multiple ADCP transects to produce a composite depiction of three-dimensional velocity fields. A new software tool, the Velocity Mapping Toolbox (VMT), is presented herein to address this important need. VMT is a Matlab-based toolbox for processing, analyzing, and displaying velocity data collected along multiple ADCP transects. The software can be used to explore patterns of three-dimensional fluid motion through several methods for calculation of secondary flows and includes capabilities for analyzing the acoustic backscatter and bathymetric data from the ADCP. A user-friendly graphical user interface (GUI) enhances program functionality and provides ready access to two- and three- dimensional plotting functions, allowing rapid display and interrogation of velocity, backscatter, and bathymetry data. This presentation describes the basic processing methods employed by VMT and highlights the capabilities of the toolbox through some example applications.

  12. Mapping of mechanical properties of cast iron melts using non-destructive structuroscopy

    Directory of Open Access Journals (Sweden)

    J. Dočekal

    2008-07-01

    Full Text Available The contribution is focused on mapping of mechanical properties using methods of non-destructive structuroscopy of cast irons, which are a result of research at TU of Liberec and Institute of Physics of ASCR. Investigated samples become from melts of FOCAM s.r.o Olomouc Foundry shop. It compares data of mechanical properties obtained using ultrasound method with data from magnetic spot method and MAT. These are interpreted by mathematic models applicable in practice. In the following it concerns to derivation of loading tensile curve method, which can be used to obtain yield and fatigue strength limits even for cast irons with flake graphite. In spite of promising results reported by literature the experiments are bothered with error. This method can be applied to structure checking both before casting and at vendor inspection of castings.

  13. Cardiac MRI. T2-mapping versus T2-weighted dark-blood TSE imaging for myocardial edema visualization in acute myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Nassenstein, K.; Nensa, F.; Schlosser, T.; Umutlu, L.; Lauenstein, T. [University Hospital Essen (Germany). Dept. of Diagnostic and Interventional Radiology and Neuroradiology; Bruder, O. [Elisabeth Hospital, Essen (Germany). Dept. of Cardiology and Angiology; Maderwald, S.; Ladd, M.E. [Duisburg-Essen Univ., Essen (Germany). Erwin L. Hahn Institute for Magnetic Resonance Imaging

    2014-02-15

    Purpose: To assess the diagnostic accuracy of T2 mapping for the detection of myocardial edema in acute myocardial infarction (AMI), and to compare this diagnostic accuracy with that of the current standard for myocardial edema imaging, which is T2w dark-blood TSE imaging. Materials and Methods: 29 patients with AMI were examined at 1.5 T. For the visualization of myocardial edema, T2 maps, calculated from three T2w SSFP images, and T2w dark-blood TSE images were acquired in standard short- and long-axis views. Cine SSFP images were acquired for the analysis of left ventricular (LV) function and late gadolinium enhancement images (LGE) for the visualization of myocardial necrosis. The T2 maps as well as the T2w dark-blood TSE images were evaluated twice independently from the cine SSFP and LGE images. The presence or absence of myocardial edema was rated visually for each LV segment. As the standard of reference, the infarct zone was defined based on the cine SSFP and the LGE images. Results: In this segment-based analysis, T2 mapping showed a sensitivity of 82 % and a specificity of 94 % for the detection of edema in the infarct zone. T2w dark-blood TSE imaging revealed a sensitivity of 50 % and a specificity of 98 %. T2 mapping showed a higher intra-rater agreement compared to T2w dark-blood TSE imaging ({kappa}: 0.87 vs. 0.76). Conclusions: T2 mapping allows for the visualization of myocardial edema in AMI with a high sensitivity and specificity, and features better diagnostic accuracy in terms of a higher sensitivity compared to T2w dark-blood TSE imaging. (orig.)

  14. SECOND GENERATION MOSAIC:A NOVEL MECHANISM BASED ON REFERENCE DATABASE FOR MAP UPDATING

    Directory of Open Access Journals (Sweden)

    G. Hu

    2012-08-01

    Full Text Available A totally new automatic workflow mechanism, named Second generation Mosaic module, based on the well-known Pixel Factory system, will be introduced here, which enables existing digital orthoimages and mosaics to be quickly updated. The process extracts all required parameters from the reference database to be able to perform automatic bundle adjustment and radiometric adaptation.In this paper, two examples for both satellite data and aerial data processed based on this mechanism will be presented here and discussed. Finally, the cost reduction will also be analysed according to the real mapping updating project.In a final statement, this paper will present an integrated solution named second generation mosaic module based on the well-known Pixel Factory system which is completely dedicated to fast processing of photogrammetric products Thanks to this integrated hardware and software solution, it is even possible to manage large data volume quickly in order to have precise map updating information as soon as possible after acquisition.

  15. Generating Orthorectified Multi-Perspective 2.5D Maps to Facilitate Web GIS-Based Visualization and Exploitation of Massive 3D City Models

    Directory of Open Access Journals (Sweden)

    Jianming Liang

    2016-11-01

    Full Text Available 2.5D map is a convenient and efficient approach to exploiting a massive three-dimensional (3D city model in web GIS. With the rapid development of oblique airborne photogrammetry and photo-based 3D reconstruction, 3D city models are becoming more and more accessible. 3D Geographic Information System (GIS can support the interactive visualization of massive 3D city models on various platforms and devices. However, the value and accessibility of existing 3D city models can be augmented by integrating them into web-based two-dimensional (2D GIS applications. In this paper, we present a step-by-step workflow for generating orthorectified oblique images (2.5D maps from massive 3D city models. The proposed framework can produce 2.5D maps from an arbitrary perspective, defined by the elevation angle and azimuth angle of a virtual orthographic camera. We demonstrate how 2.5D maps can benefit web-based visualization and exploitation of massive 3D city models. We conclude that a 2.5D map is a compact data representation optimized for web data streaming of 3D city models and that geometric analysis of buildings can be effectively conducted on 2.5D maps.

  16. The gastrointestinal electrical mapping suite (GEMS): software for analyzing and visualizing high-resolution (multi-electrode) recordings in spatiotemporal detail.

    Science.gov (United States)

    Yassi, Rita; O'Grady, Gregory; Paskaranandavadivel, Nira; Du, Peng; Angeli, Timothy R; Pullan, Andrew J; Cheng, Leo K; Erickson, Jonathan C

    2012-06-06

    Gastrointestinal contractions are controlled by an underlying bioelectrical activity. High-resolution spatiotemporal electrical mapping has become an important advance for investigating gastrointestinal electrical behaviors in health and motility disorders. However, research progress has been constrained by the low efficiency of the data analysis tasks. This work introduces a new efficient software package: GEMS (Gastrointestinal Electrical Mapping Suite), for analyzing and visualizing high-resolution multi-electrode gastrointestinal mapping data in spatiotemporal detail. GEMS incorporates a number of new and previously validated automated analytical and visualization methods into a coherent framework coupled to an intuitive and user-friendly graphical user interface. GEMS is implemented using MATLAB®, which combines sophisticated mathematical operations and GUI compatibility. Recorded slow wave data can be filtered via a range of inbuilt techniques, efficiently analyzed via automated event-detection and cycle clustering algorithms, and high quality isochronal activation maps, velocity field maps, amplitude maps, frequency (time interval) maps and data animations can be rapidly generated. Normal and dysrhythmic activities can be analyzed, including initiation and conduction abnormalities. The software is distributed free to academics via a community user website and forum (http://sites.google.com/site/gimappingsuite). This software allows for the rapid analysis and generation of critical results from gastrointestinal high-resolution electrical mapping data, including quantitative analysis and graphical outputs for qualitative analysis. The software is designed to be used by non-experts in data and signal processing, and is intended to be used by clinical researchers as well as physiologists and bioengineers. The use and distribution of this software package will greatly accelerate efforts to improve the understanding of the causes and clinical consequences of

  17. The gastrointestinal electrical mapping suite (GEMS: software for analyzing and visualizing high-resolution (multi-electrode recordings in spatiotemporal detail

    Directory of Open Access Journals (Sweden)

    Yassi Rita

    2012-06-01

    Full Text Available Abstract Background Gastrointestinal contractions are controlled by an underlying bioelectrical activity. High-resolution spatiotemporal electrical mapping has become an important advance for investigating gastrointestinal electrical behaviors in health and motility disorders. However, research progress has been constrained by the low efficiency of the data analysis tasks. This work introduces a new efficient software package: GEMS (Gastrointestinal Electrical Mapping Suite, for analyzing and visualizing high-resolution multi-electrode gastrointestinal mapping data in spatiotemporal detail. Results GEMS incorporates a number of new and previously validated automated analytical and visualization methods into a coherent framework coupled to an intuitive and user-friendly graphical user interface. GEMS is implemented using MATLAB®, which combines sophisticated mathematical operations and GUI compatibility. Recorded slow wave data can be filtered via a range of inbuilt techniques, efficiently analyzed via automated event-detection and cycle clustering algorithms, and high quality isochronal activation maps, velocity field maps, amplitude maps, frequency (time interval maps and data animations can be rapidly generated. Normal and dysrhythmic activities can be analyzed, including initiation and conduction abnormalities. The software is distributed free to academics via a community user website and forum (http://sites.google.com/site/gimappingsuite. Conclusions This software allows for the rapid analysis and generation of critical results from gastrointestinal high-resolution electrical mapping data, including quantitative analysis and graphical outputs for qualitative analysis. The software is designed to be used by non-experts in data and signal processing, and is intended to be used by clinical researchers as well as physiologists and bioengineers. The use and distribution of this software package will greatly accelerate efforts to improve the

  18. Mapping Large-Scale Mechanized Agriculture Across the Brazilian Cerrado Between 2001-2013

    Science.gov (United States)

    Spera, S. A.; Mustard, J. F.; VanWey, L.

    2014-12-01

    Brazil is a global commodities powerhouse. Over the last decade, dynamic changes in agricultural development and land transformations occurred within Brazil's tropical savanna region, the cerrado. This interdisciplinary study uses remote sensing tools to map land cover across more than 3.6 million km2 of cerrado and statistical methods to characterize drivers of this land-cover change. We use the MODIS Enhanced Vegetation Index 16-day data product and a decision-tree algorithm, proven highly accurate in Mato Grosso (Spera et al. 2014) and here modified for the broader cerrado region, to characterize crop type, cropping frequency, expansion, and abandonment of large-scale mechanized agriculture during the 2001-2013 period. The algorithm exploits phenological differences between forest, pasture and cerrado, and mechanized agriculture. It is parameterized to distinguish between crop rotations in Mato Grosso, Goias, and the new agricultural frontier spanning Maranhao, Tocantins, Piaui, and Bahia (MaToPiBa). Training and validation data were collected using Google's Earth Engine. We map single-cropped soy, corn, and cotton; double-cropped soy/corn and soy/cotton rotations; and irrigated agriculture across these six Brazilian cerrado states. We find that while double cropping dominates in Mato Grosso and Goias, single cropping is still the dominant form of mechanized agriculture in the burgeoning MaToPiBa region. In western Bahia alone, preliminary results show agriculture has expanded by almost 350,000 ha and double cropping has increased by almost 40,000 ha. With MaToPiBa touted as Brazil's latest and last agricultural frontier, we predict that the region will experience a transition similar to that of Mato Grosso during the 2000s—an expansion and intensification of agriculture—which may beget unprecedented ramifications on regional climate processes that can then affect ecosystem health and the economic feasibility of cultivating rain-fed export crops.

  19. Resonance Raman examination of the wavelength regulation mechanism in human visual pigments.

    Science.gov (United States)

    Kochendoerfer, G G; Wang, Z; Oprian, D D; Mathies, R A

    1997-06-03

    Resonance Raman spectra of recombinant human green and red cone pigments have been obtained to examine the molecular mechanism of color recognition by visual pigments. Spectra were acquired using a 77 K resonance Raman microprobe or preresonance Raman spectroscopy. The vibrational bands were assigned by comparison to the spectra of bovine rhodopsin and model compounds. The C=NH stretching frequencies of rhodopsin, the green cone pigment, and the red cone pigment in H2O (D2O) are found at 1656 (1623), 1640 (1618), and 1644 cm(-1), respectively. Together with previous resonance Raman studies on iodopsin [Lin, S. W., Imamoto, Y., Fukada, Y., Shichida, Y., Yoshizawa, T., & Mathies, R. A. (1994) Biochemistry 33, 2151-2160], these values suggest that red and green pigments have very similar Schiff base environments, while the Schiff base group in rhodopsin is more strongly hydrogen-bonded to its protein environment. The absence of significant frequency and intensity differences of modes in the fingerprint and the hydrogen out-of-plane wagging regions for all these pigments does not support the hypothesis that local chromophore interactions with charged protein residues and/or chromophore planarization are crucial for the absorption differences among these pigments. However, our data are consistent with the idea that the Schiff base group in blue visual pigments is stabilized by protein and water dipoles and that the removal of this dipolar field shifts the absorption maximum from blue to green. A further red shift of the lambda(max) from the green to the red pigment is successfully modeled by the addition of hydroxyl-bearing amino acids (Ser164, Tyr261, and Thr269) close to the ionone ring that lower the transition energy by interacting with the change of dipole moment of the chromophore upon excitation. The increased hydrogen bonding of the protonated Schiff base group in rhodopsin is predicted to account for the 30 nm blue shift of its absorption maximum compared to

  20. Seep Mapping: Using NOAA Ship Okeanos Explorer Data to Visualize the Physical Environments of Seeps in the Gulf of Mexico

    Science.gov (United States)

    Auner, L.; McKenna, L.; Lobecker, E.; Sowers, D.

    2014-12-01

    More than 550 possible gaseous seeps were previously identified along the continental margin in the northwestern Gulf of Mexico using water-column acoustic backscatter data collected on the NOAA Ship Okeanos Explorer in the spring of 2014. Although the presence of macro-seeps can only be verified through visual confirmation, several studies suggest that gaseous bubbles emitted by seeps are uniquely detected in sonar water-column backscatter returns (Judd and Hovland, 1992; Nikolovska et al., 2008; Weber et al., 2012). In this study, more than 200 seeps were independently identified from a subset of water-column backscatter data collected in March and April, 2014. Additional data collected aboard the Okeanos Explorer includes bathymetry, seafloor backscatter, sub-bottom seismic reflection profiles, and ROV video footage. These datasets, along with calculated geomorphic parameters such as slope, were used to develop specialized mapping products to display physical characteristics of the seafloor and subsurface surrounding a number of gaseous seeps. Preliminary results indicate that seeps occur in a wide variety of geomorphic settings, including the edges of salt domes, and at depths ranging from approximately 300 meters to 1,100 meters. Study results could be used to make predictions about where seeps are most likely to be detected along the continental margin of the northwestern Gulf of Mexico. These predictions could inform future efforts to study seeps and their associated biological communities within the study area or aid in the development of larger scale seep characterization and predictive modeling.

  1. A technique for visualization and mapping of local cartilage thickness changes in MR images of osteoarthritic knee

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Quanxu, E-mail: gequanxu@yahoo.com.cn [Department of Radiology, Weihai Municipal Hospital, Weihai City, Shandong Province, 164200 (China); Cheng, Yuanzhi, E-mail: yzcheng@hitwh.edu.cn [School of Computer Science and Technology, Harbin Institute of Technology, Harbin, 150001 (China); Bi, Kesen, E-mail: whbks@yahoo.com.cn [Department of Radiology, Weihai Municipal Hospital, Weihai City, Shandong Province, 164200 (China); Guo, Changyong, E-mail: hit_gcy@163.com [School of Computer Science and Technology, Harbin Institute of Technology, Harbin, 150001 (China); Bai, Jing, E-mail: deabj@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, China B209, Medical School Building, Tsinghua University, Beijing, 100084 (China); Tamura, Shinichi, E-mail: tamuras@nblmt.jp [Center for Advanced Medical Engineering and Informatics, Osaka University, D11, 2-2, Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2012-11-15

    Purpose: The aim of this paper is to describe a technique for the visualization and mapping of focal, local cartilage thickness changes over time in magnetic resonance images of osteoarthritic knee. Methods: Magnetic resonance imaging was performed in 25 fresh frozen pig knee joints and 15 knees of patients with borderline to mild osteoarthritis (51.2 {+-} 6.3 years). Cartilage and corresponding bone structures were extracted by semi-automatic segmentation. Each point in the bone surface which was part of the bone-cartilage interface was assigned a cartilage thickness value. Cartilage thicknesses were computed for each point in the bone-cartilage interfaces and transferred to the bone surfaces. Moreover, we developed a three dimensional registration method for the identification of anatomically corresponding points of the bone surface to quantify local cartilage thickness changes. One of the main advantages of our method compared to other studies in the field of registration is a global optimization algorithm that does not require any initialization. Results and conclusion: The registration accuracy was 0.93 {+-} 0.05 mm (less than a voxel of magnetic resonance data). Local cartilage thickness changes were seen as having follow-up clinical study for detecting local changes in cartilage thickness. Experiment results suggest that our method was sufficiently accurate and effective for monitoring knee joint diseases.

  2. CGI: Java Software for Mapping and Visualizing Data from Array-based Comparative Genomic Hybridization and Expression Profiling

    Directory of Open Access Journals (Sweden)

    Joyce Xiuweu-Xu Gu

    2007-01-01

    Full Text Available With the increasing application of various genomic technologies in biomedical research, there is a need to integrate these data to correlate candidate genes/regions that are identified by different genomic platforms. Although there are tools that can analyze data from individual platforms, essential software for integration of genomic data is still lacking. Here, we present a novel Java-based program called CGI (Cytogenetics-Genomics Integrator that matches the BAC clones from array-based comparative genomic hybridization (aCGH to genes from RNA expression profiling datasets. The matching is computed via a fast, backend MySQL database containing UCSC Genome Browser annotations. This program also provides an easy-to-use graphical user interface for visualizing and summarizing the correlation of DNA copy number changes and RNA expression patterns from a set of experiments. In addition, CGI uses a Java applet to display the copy number values of a specifi c BAC clone in aCGH experiments side by side with the expression levels of genes that are mapped back to that BAC clone from the microarray experiments. The CGI program is built on top of extensible, reusable graphic components specifically designed for biologists. It is cross-platform compatible and the source code is freely available under the General Public License.

  3. Precise Visualization Method for Cultural Heritage-The Case of High-Resolution Read Relief Image Map Used for Study of Royal City of Angkor Thom, Cambodia

    Science.gov (United States)

    Chiba, T.; Shimoda, I.; Haraguchi, T.; Shimoda, M.

    2016-06-01

    To precisely visualize the Royal City of Angkor Thom, Cambodia, we used a new method in field of cultural heritage study. Read Relief Image Map (RRIM, Chiba et al., 2008) is a powerful method which has been used for geomorphological studies. In this study, using the LiDAR data conducted at the Angkor Archaeological Park in Cambodia in April 2012 (Evans et al., 2013), we visualized the Royal City of Angkor Thom and its vicinity (Shimoda et al., 2016). The RRIM provided a new visualization method of localizing, minute topographical changes in regions with large undulations over a wide area. It has proved to be effective in mapping, on a single wide-area map, the numerous buried remains that exist as comparable height differences or minute undulations measuring less than 1 meter in height, and provides a unique aerial view of their widespread distribution. Based on the RRIM map, past archaeological studies were referenced to reconstruct the layout of the water channel network system. Past studies revealed that a large number of ponds had been dug inside Angkor Thom. The RRIM expanded the investigation and revealed the existence of many ponds outside the royal capital indicating that a residential community had flourished outside the moat surrounded capital city.

  4. Visual Field Map Clusters in High-Order Visual Processing: Organization of V3A/V3B and a New Cloverleaf Cluster in the Posterior Superior Temporal Sulcus.

    Science.gov (United States)

    Barton, Brian; Brewer, Alyssa A

    2017-01-01

    The cortical hierarchy of the human visual system has been shown to be organized around retinal spatial coordinates throughout much of low- and mid-level visual processing. These regions contain visual field maps (VFMs) that each follows the organization of the retina, with neighboring aspects of the visual field processed in neighboring cortical locations. On a larger, macrostructural scale, groups of such sensory cortical field maps (CFMs) in both the visual and auditory systems are organized into roughly circular cloverleaf clusters. CFMs within clusters tend to share properties such as receptive field distribution, cortical magnification, and processing specialization. Here we use fMRI and population receptive field (pRF) modeling to investigate the extent of VFM and cluster organization with an examination of higher-level visual processing in temporal cortex and compare these measurements to mid-level visual processing in dorsal occipital cortex. In human temporal cortex, the posterior superior temporal sulcus (pSTS) has been implicated in various neuroimaging studies as subserving higher-order vision, including face processing, biological motion perception, and multimodal audiovisual integration. In human dorsal occipital cortex, the transverse occipital sulcus (TOS) contains the V3A/B cluster, which comprises two VFMs subserving mid-level motion perception and visuospatial attention. For the first time, we present the organization of VFMs in pSTS in a cloverleaf cluster. This pSTS cluster contains four VFMs bilaterally: pSTS-1:4. We characterize these pSTS VFMs as relatively small at ∼125 mm2 with relatively large pRF sizes of ∼2-8° of visual angle across the central 10° of the visual field. V3A and V3B are ∼230 mm2 in surface area, with pRF sizes here similarly ∼1-8° of visual angle across the same region. In addition, cortical magnification measurements show that a larger extent of the pSTS VFM surface areas are devoted to the peripheral visual

  5. Cardiac MRI: T2-Mapping Versus T2-Weighted Dark-Blood TSE Imaging for Myocardial Edema Visualization in Acute Myocardial Infarction.

    Science.gov (United States)

    Naßenstein, K; Nensa, F; Schlosser, T; Bruder, O; Umutlu, L; Lauenstein, T; Maderwald, S; Ladd, M E

    2014-02-01

    To assess the diagnostic accuracy of T2 mapping for the detection of myocardial edema in acute myocardial infarction (AMI), and to compare this diagnostic accuracy with that of the current standard for myocardial edema imaging, which is T2w dark-blood TSE imaging. 29 patients with AMI were examined at 1.5 T. For the visualization of myocardial edema, T2 maps, calculated from three T2w SSFP images, and T2w dark-blood TSE images were acquired in standard short- and long-axis views. Cine SSFP images were acquired for the analysis of left ventricular (LV) function and late gadolinium enhancement images (LGE) for the visualization of myocardial necrosis. The T2 maps as well as the T2w dark-blood TSE images were evaluated twice independently from the cine SSFP and LGE images. The presence or absence of myocardial edema was rated visually for each LV segment. As the standard of reference, the infarct zone was defined based on the cine SSFP and the LGE images. In this segment-based analysis, T2 mapping showed a sensitivity of 82 % and a specificity of 94 % for the detection of edema in the infarct zone. T2w dark-blood TSE imaging revealed a sensitivity of 50 % and a specificity of 98 %. T2 mapping showed a higher intra-rater agreement compared to T2w dark-blood TSE imaging (κ: 0.87 vs. 0.76). T2 mapping allows for the visualization of myocardial edema in AMI with a high sensitivity and specificity, and features better diagnostic accuracy in terms of a higher sensitivity compared to T2w dark-blood TSE imaging. Citation Format: • Naßenstein K, Nensa F, Schlosser T et al. Cardiac MRI: T2-Mapping Versus T2-Weighted Dark-Blood TSE Imaging for Myocardial Edema Visualization in Acute Myocardial Infarction. Fortschr Röntgenstr 2014; 186: 166 - 172. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Molecular Mechanisms at the Basis of Plasticity in the Developing Visual Cortex: Epigenetic Processes and Gene Programs

    Directory of Open Access Journals (Sweden)

    José Fernando Maya-Vetencourt

    2013-01-01

    Full Text Available Neuronal circuitries in the mammalian visual system change as a function of experience. Sensory experience modifies neuronal networks connectivity via the activation of different physiological processes such as excitatory/inhibitory synaptic transmission, neurotrophins, and signaling of extracellular matrix molecules. Long-lasting phenomena of plasticity occur when intracellular signal transduction pathways promote epigenetic alterations of chromatin structure that regulate the induction of transcription factors that in turn drive the expression of downstream targets, the products of which then work via the activation of structural and functional mechanisms that modify synaptic connectivity. Here, we review recent findings in the field of visual cortical plasticity while focusing on how physiological mechanisms associated with experience promote structural changes that determine functional modifications of neural circuitries in V1. We revise the role of microRNAs as molecular transducers of environmental stimuli and the role of immediate early genes that control gene expression programs underlying plasticity in the developing visual cortex.

  7. Two different motor learning mechanisms contribute to learning reaching movements in a rotated visual environment.

    Science.gov (United States)

    Chu, Virginia Way Tong; Sanger, Terence David

    2014-01-01

    Practice of movement in virtual-reality and other artificially altered environments has been proposed as a method for rehabilitation following neurological injury and for training new skills in healthy humans.  For such training to be useful, there must be transfer of learning from the artificial environment to the performance of desired skills in the natural environment.  Therefore an important assumption of such methods is that practice in the altered environment engages the same learning and plasticity mechanisms that are required for skill performance in the natural environment.  We test the hypothesis that transfer of learning may fail because the learning and plasticity mechanism that adapts to the altered environment is different from the learning mechanism required for improvement of motor skill.  In this paper, we propose that a model that separates skill learning and environmental adaptation is necessary to explain the learning and aftereffects that are observed in virtual reality experiments.  In particular, we studied the condition where practice in the altered environment should lead to correct skill performance in the original environment. Our 2-mechanism model predicts that aftereffects will still be observed when returning to the original environment, indicating a lack of skill transfer from the artificial environment to the original environment. To illustrate the model prediction, we tested 10 healthy participants on the interaction between a simple overlearned motor skill (straight hand movements to targets in different directions) and an artificially altered visuomotor environment (rotation of visual feedback of the results of movement).  As predicted by the models, participants show adaptation to the altered environment and after-effects on return to the baseline environment even when practice in the altered environment should have led to correct skill performance.  The presence of aftereffect under all conditions that involved changes in

  8. Development of an in vivo visual robot system with a magnetic anchoring mechanism and a lens cleaning mechanism for laparoendoscopic single-site surgery (LESS).

    Science.gov (United States)

    Feng, Haibo; Dong, Dinghui; Ma, Tengfei; Zhuang, Jinlei; Fu, Yili; Lv, Yi; Li, Liyi

    2017-12-01

    Surgical robot systems which can significantly improve surgical procedures have been widely used in laparoendoscopic single-site surgery (LESS). For a relative complex surgical procedure, the development of an in vivo visual robot system for LESS can effectively improve the visualization for surgical robot systems. In this work, an in vivo visual robot system with a new mechanism for LESS was investigated. A finite element method (FEM) analysis was carried out to ensure the safety of the in vivo visual robot during the movement, which was the most important concern for surgical purposes. A master-slave control strategy was adopted, in which the control model was established by off-line experiments. The in vivo visual robot system was verified by using a phantom box. The experiment results show that the robot system can successfully realize the expected functionalities and meet the demands of LESS. The experiment results indicate that the in vivo visual robot with high manipulability has great potential in clinical application. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Visual loss in HIV-associated cryptococcal meningitis: A case series and review of the mechanisms involved

    Directory of Open Access Journals (Sweden)

    Anand Moodley

    2015-04-01

    Full Text Available Permanent visual loss is a devastating yet preventable complication of cryptococcal meningitis. Early and aggressive management of cerebrospinal fluid pressure in conjunction with antifungal therapy is required. Historically, the mechanisms of visual loss in cryptococcal meningitis have included optic neuritis and papilloedema. Hence, the basis of visual loss therapy has been steroid therapy and intracranial pressure lowering without clear guidelines. With the use of high-resolution magnetic resonance imaging of the optic nerve, an additional mechanism has emerged, namely an optic nerve sheath compartment syndrome (ONSCS caused by severely elevated intracranial pressure and fungal loading in the peri-optic space. An improved understanding of these mechanisms and recognition of the important role played by raised intracranial pressure allows for more targeted treatment measures and better outcomes. In the present case series of 90 HIV co-infected patients with cryptococcal meningitis, we present the clinical and electrophysiological manifestations of Cryptococcus-induced visual loss and review the mechanisms involved.

  10. Visual loss in HIV-associated cryptococcal meningitis: A case series and review of the mechanisms involved

    Directory of Open Access Journals (Sweden)

    Anand Moodley

    2015-10-01

    Full Text Available Permanent visual loss is a devastating yet preventable complication of cryptococcal meningitis. Early and aggressive management of cerebrospinal fluid pressure in conjunction with antifungal therapy is required. Historically, the mechanisms of visual loss in cryptococcal meningitis have included optic neuritis and papilloedema. Hence, the basis of visual loss therapy has been steroid therapy and intracranial pressure lowering without clear guidelines. With the use of high-resolution magnetic resonance imaging of the optic nerve, an additional mechanism has emerged, namely an optic nerve sheath compartment syndrome (ONSCS caused by severely elevated intracranial pressure and fungal loading in the peri-optic space. An improved understanding of these mechanisms and recognition of the important role played by raised intracranial pressure allows for more targeted treatment measures and better outcomes. In the present case series of 90 HIV co-infected patients with cryptococcal meningitis, we present the clinical and electrophysiological manifestations of Cryptococcus-induced visual loss and review the mechanisms involved.

  11. Search for and limits on plume activity on Mimas, Tethys, and Dione with the Cassini Visual Infrared Mapping Spectrometer (VIMS)

    Science.gov (United States)

    Buratti, B.J.; Faulk, S.P.; Mosher, J.; Baines, K.H.; Brown, R.H.; Clark, R.N.; Nicholson, P.D.

    2011-01-01

    Cassini Visual Infrared Mapping Spectrometer (VIMS) observations of Mimas, Tethys, and Dione obtained during the nominal and extended missions at large solar phase angles were analyzed to search for plume activity. No forward scattered peaks in the solar phase curves of these satellites were detected. The upper limit on water vapor production for Mimas and Tethys is one order of magnitude less than the production for Enceladus. For Dione, the upper limit is two orders of magnitude less, suggesting this world is as inert as Rhea (Pitman, K.M., Buratti, B.J., Mosher, J.A., Bauer, J.M., Momary, T., Brown, R.H., Nicholson, P.D., Hedman, M.M. [2008]. Astrophys. J. Lett. 680, L65-L68). Although the plumes are best seen at ???2.0. ??m, Imaging Science Subsystem (ISS) Narrow Angle Camera images obtained at the same time as the VIMS data were also inspected for these features. None of the Cassini ISS images shows evidence for plumes. The absence of evidence for any Enceladus-like plumes on the medium-sized saturnian satellites cannot absolutely rule out current geologic activity. The activity may below our threshold of detection, or it may be occurring but not captured on the handful of observations at large solar phase angles obtained for each moon. Many VIMS and ISS images of Enceladus at large solar phase angles, for example, do not contain plumes, as the active "tiger stripes" in the south pole region are pointed away from the spacecraft at these times. The 7-year Cassini Solstice Mission is scheduled to gather additional measurements at large solar phase angles that are capable of revealing activity on the saturnian moons. ?? 2011 Elsevier Inc.

  12. Top-Down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action.

    Science.gov (United States)

    Wang, Chao; Rajagovindan, Rajasimhan; Han, Sahng-Min; Ding, Mingzhou

    2016-01-01

    Alpha oscillations (8-12 Hz) are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out stimulus input to protect the information held online from sensory interference. According to the prevailing model, this goal-oriented biasing of sensory cortex is effected by top-down control signals from frontal and parietal cortices. The present study tests and substantiates this hypothesis by (a) identifying the signals that mediate the top-down biasing influence, (b) examining whether the cortical areas issuing these signals are task-specific or task-independent, and (c) establishing the possible mechanism of the biasing action. High-density human EEG data were recorded in two experimental paradigms: a trial-by-trial cued visual spatial attention task and a modified Sternberg working memory task. Applying Granger causality to both sensor-level and source-level data we report the following findings. In covert visual spatial attention, the regions exerting top-down control over visual activity are lateralized to the right hemisphere, with the dipoles located at the right frontal eye field (FEF) and the right inferior frontal gyrus (IFG) being the main sources of top-down influences. During retention of verbal working memory, the regions exerting top-down control over visual activity are lateralized to the left hemisphere, with the dipoles located at the left middle frontal gyrus (MFG) being the main source of top-down influences. In both experiments, top-down influences are mediated by alpha oscillations, and the biasing effect is likely achieved via an inhibition

  13. Top-down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action

    Directory of Open Access Journals (Sweden)

    Chao eWang

    2016-01-01

    Full Text Available Alpha oscillations (8 to 12 Hz are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out stimulus input to protect the information held online from sensory interference. According to the prevailing model, this goal-oriented biasing of sensory cortex is effected by top-down control signals from frontal and parietal cortices. The present study tests and substantiates this hypothesis by (a identifying the signals that mediate the top-down biasing influence, (b examining whether the cortical areas issuing these signals are task-specific or task-independent, and (c establishing the possible mechanism of the biasing action. High-density human EEG data were recorded in two experimental paradigms: a trial-by-trial cued visual spatial attention task and a modified Sternberg working memory task. Applying Granger causality to both sensor-level and source-level data we report the following findings. In covert visual spatial attention, the regions exerting top-down control over visual activity are lateralized to the right hemisphere, with the dipoles located at the right frontal eye field (FEF and the right inferior frontal gyrus (IFG being the main sources of top-down influences. During retention of verbal working memory, the regions exerting top-down control over visual activity are lateralized to the left hemisphere, with the dipoles located at the left middle frontal gyrus (MFG being the main source of top-down influences. In both experiments, top-down influences are mediated by alpha oscillations, and the biasing effect is likely achieved via an

  14. Arrhythmia Mechanism and Scaling Effect on the Spectral Properties of Electroanatomical Maps with Manifold Harmonics.

    Science.gov (United States)

    Sanroman-Junquera, Margarita; Mora-Jimenez, Inmaculada; Garcia-Alberola, Arcadi; Caamano, Antonio J; Trenor, Beatriz; Rojo-Alvarez, Jose Luis

    2017-06-15

    Spatial and temporal processing of intracardiac electrograms provides relevant information to support the arrhythmia ablation during electrophysiological studies. Current Cardiac Navigation Systems (CNS) and Electrocardiographic Imaging (ECGI) build detailed three-dimensional electroanatomical maps (EAM), which represent the spatial anatomical distribution of bioelectrical features, such as activation time or voltage. We present a principled methodology for spectral analysis of both EAM geometry and bioelectrical feature in CNS or ECGI, including their spectral representation, cut-off frequency, or spatial sampling rate (SSR). Existing manifold harmonic techniques for spectral mesh analysis are adapted to account for a fourth dimension, corresponding to the EAM bioelectrical feature. Appropriate scaling is required to address different magnitudes and units. With our approach, simulated and real EAM showed strong SSR dependence on both the arrhythmia mechanism and the cardiac anatomical shape. For instance, high frequencies increased significantly the SSR because of the ``early-meets-late'' in flutter EAM, compared with the sinus rhythm. Besides, higher frequency components were obtained for the left atrium (more complex anatomy) than for the right atrium in sinus rhythm. The proposed manifold harmonics methodology opens the field towards new signal processing tools for principled EAM spatio-feature analysis in CNS and ECGI, and to an improved knowledge on arrhythmia mechanisms.

  15. Exploring the Impact of Visual Complexity Levels in 3d City Models on the Accuracy of Individuals' Orientation and Cognitive Maps

    Science.gov (United States)

    Rautenbach, V.; Çöltekin, A.; Coetzee, S.

    2015-08-01

    In this paper we report results from a qualitative user experiment (n=107) designed to contribute to understanding the impact of various levels of complexity (mainly based on levels of detail, i.e., LoD) in 3D city models, specifically on the participants' orientation and cognitive (mental) maps. The experiment consisted of a number of tasks motivated by spatial cognition theory where participants (among other things) were given orientation tasks, and in one case also produced sketches of a path they `travelled' in a virtual environment. The experiments were conducted in groups, where individuals provided responses on an answer sheet. The preliminary results based on descriptive statistics and qualitative sketch analyses suggest that very little information (i.e., a low LoD model of a smaller area) might have a negative impact on the accuracy of cognitive maps constructed based on a virtual experience. Building an accurate cognitive map is an inherently desired effect of the visualizations in planning tasks, thus the findings are important for understanding how to develop better-suited 3D visualizations such as 3D city models. In this study, we specifically discuss the suitability of different levels of visual complexity for development planning (urban planning), one of the domains where 3D city models are most relevant.

  16. Orienting Attention within Visual Short-Term Memory: Development and Mechanisms

    Science.gov (United States)

    Shimi, Andria; Nobre, Anna C.; Astle, Duncan; Scerif, Gaia

    2014-01-01

    How does developing attentional control operate within visual short-term memory (VSTM)? Seven-year-olds, 11-year-olds, and adults (total n = 205) were asked to report whether probe items were part of preceding visual arrays. In Experiment 1, central or peripheral cues oriented attention to the location of to-be-probed items either prior to…

  17. Fluorescent molecular rotors : From working principles to visualization of mechanical contacts

    NARCIS (Netherlands)

    Suhina, T.

    2017-01-01

    In this thesis, we develop and characterize a method that enables us to visualize the real microscopic contact area between objects, using fluorescent molecules. Visualization and the ability to predict the real contact area between touching objects is a subject of a considerable interest, because

  18. Map Learning with a 3D Printed Interactive Small-Scale Model: Improvement of Space and Text Memorization in Visually Impaired Students

    Directory of Open Access Journals (Sweden)

    Stéphanie Giraud

    2017-06-01

    Full Text Available Special education teachers for visually impaired students rely on tools such as raised-line maps (RLMs to teach spatial knowledge. These tools do not fully and adequately meet the needs of the teachers because they are long to produce, expensive, and not versatile enough to provide rapid updating of the content. For instance, the same RLM can barely be used during different lessons. In addition, those maps do not provide any interactivity, which reduces students’ autonomy. With the emergence of 3D printing and low-cost microcontrollers, it is now easy to design affordable interactive small-scale models (SSMs which are adapted to the needs of special education teachers. However, no study has previously been conducted to evaluate non-visual learning using interactive SSMs. In collaboration with a specialized teacher, we designed a SSM and a RLM representing the evolution of the geography and history of a fictitious kingdom. The two conditions were compared in a study with 24 visually impaired students regarding the memorization of the spatial layout and historical contents. The study showed that the interactive SSM improved both space and text memorization as compared to the RLM with braille legend. In conclusion, we argue that affordable home-made interactive small scale models can improve learning for visually impaired students. Interestingly, they are adaptable to any teaching situation including students with specific needs.

  19. Map Learning with a 3D Printed Interactive Small-Scale Model: Improvement of Space and Text Memorization in Visually Impaired Students

    Science.gov (United States)

    Giraud, Stéphanie; Brock, Anke M.; Macé, Marc J.-M.; Jouffrais, Christophe

    2017-01-01

    Special education teachers for visually impaired students rely on tools such as raised-line maps (RLMs) to teach spatial knowledge. These tools do not fully and adequately meet the needs of the teachers because they are long to produce, expensive, and not versatile enough to provide rapid updating of the content. For instance, the same RLM can barely be used during different lessons. In addition, those maps do not provide any interactivity, which reduces students’ autonomy. With the emergence of 3D printing and low-cost microcontrollers, it is now easy to design affordable interactive small-scale models (SSMs) which are adapted to the needs of special education teachers. However, no study has previously been conducted to evaluate non-visual learning using interactive SSMs. In collaboration with a specialized teacher, we designed a SSM and a RLM representing the evolution of the geography and history of a fictitious kingdom. The two conditions were compared in a study with 24 visually impaired students regarding the memorization of the spatial layout and historical contents. The study showed that the interactive SSM improved both space and text memorization as compared to the RLM with braille legend. In conclusion, we argue that affordable home-made interactive small scale models can improve learning for visually impaired students. Interestingly, they are adaptable to any teaching situation including students with specific needs. PMID:28649209

  20. Surface analysis and mechanical behaviour mapping of vertically aligned CNT forest array through nanoindentation

    Energy Technology Data Exchange (ETDEWEB)

    Koumoulos, Elias P.; Charitidis, C.A., E-mail: charitidis@chemeng.ntua.gr

    2017-02-28

    Highlights: • Structure and wall numbers are identified through TEM. • Static contact angle measurements revealed a super-hydrophobic behavior. • Hysteresis was observed (loading–unloading) due to the local stress distribution. • Hardness and modulus mapping for a grid of 70 μm{sup 2} is conducted. • Resistance is clearly divided in 2 regions (MWCNT and MWCNT – MWCNT) interface. - Abstract: Carbon nanotube (CNT) based architectures have increased the scientific interest owning to their exceptional performance rendering them promising candidates for advanced industrial applications in the nanotechnology field. Despite individual CNTs being considered as one of the most known strong materials, much less is known about other CNT forms, such as CNT arrays, in terms of their mechanical performance (integrity). In this work, thermal chemical vapor deposition (CVD) method is employed to produce vertically aligned multiwall (VA-MW) CNT carpets. Their structural properties were studied by means of scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Raman spectroscopy, while their hydrophobic behavior was investigated via contact angle measurements. The resistance to indentation deformation of VA-MWCNT carpets was investigated through nanoindentation technique. The synthesized VA-MWCNTs carpets consisted of well-aligned MWCNTs. Static contact angle measurements were performed with water and glycerol, revealing a rather super-hydrophobic behavior. The structural analysis, hydrophobic behavior and indentation response of VA-MWCNTs carpets synthesized via CVD method are clearly demonstrated. Additionally, cycle indentation load-depth curve was applied and hysteresis loops were observed in the indenter loading–unloading cycle due to the local stress distribution. Hardness (as resistance to applied load) and modulus mapping, at 200 nm of displacement for a grid of 70 μm{sup 2} is presented. Through trajection, the resistance is clearly divided in 2

  1. Investigation into local cell mechanics by atomic force microscopy mapping and optical tweezer vertical indentation

    Science.gov (United States)

    Coceano, G.; Yousafzai, M. S.; Ma, W.; Ndoye, F.; Venturelli, L.; Hussain, I.; Bonin, S.; Niemela, J.; Scoles, G.; Cojoc, D.; Ferrari, E.

    2016-02-01

    Investigating the mechanical properties of cells could reveal a potential source of label-free markers of cancer progression, based on measurable viscoelastic parameters. The Young’s modulus has proved to be the most thoroughly studied so far, however, even for the same cell type, the elastic modulus reported in different studies spans a wide range of values, mainly due to the application of different experimental conditions. This complicates the reliable use of elasticity for the mechanical phenotyping of cells. Here we combine two complementary techniques, atomic force microscopy (AFM) and optical tweezer microscopy (OTM), providing a comprehensive mechanical comparison of three human breast cell lines: normal myoepithelial (HBL-100), luminal breast cancer (MCF-7) and basal breast cancer (MDA-MB-231) cells. The elastic modulus was measured locally by AFM and OTM on single cells, using similar indentation approaches but different measurement parameters. Peak force tapping AFM was employed at nanonewton forces and high loading rates to draw a viscoelastic map of each cell and the results indicated that the region on top of the nucleus provided the most meaningful results. OTM was employed at those locations at piconewton forces and low loading rates, to measure the elastic modulus in a real elastic regime and rule out the contribution of viscous forces typical of AFM. When measured by either AFM or OTM, the cell lines’ elasticity trend was similar for the aggressive MDA-MB-231 cells, which were found to be significantly softer than the other two cell types in both measurements. However, when comparing HBL-100 and MCF-7 cells, we found significant differences only when using OTM.

  2. The Arctic Research Mapping Application (ARMAP): a Geoportal for Visualizing Project-level Information About U.S. Funded Research in the Arctic

    Science.gov (United States)

    Kassin, A.; Cody, R. P.; Barba, M.; Gaylord, A. G.; Manley, W. F.; Score, R.; Escarzaga, S. M.; Tweedie, C. E.

    2016-12-01

    The Arctic Research Mapping Application (ARMAP; http://armap.org/) is a suite of online applications and data services that support Arctic science by providing project tracking information (who's doing what, when and where in the region) for United States Government funded projects. In collaboration with 17 research agencies, project locations are displayed in a visually enhanced web mapping application. Key information about each project is presented along with links to web pages that provide additional information, including links to data where possible. The latest ARMAP iteration has i) reworked the search user interface (UI) to enable multiple filters to be applied in user-driven queries and ii) implemented ArcGIS Javascript API 4.0 to allow for deployment of 3D maps directly into a users web-browser and enhanced customization of popups. Module additions include i) a dashboard UI powered by a back-end Apache SOLR engine to visualize data in intuitive and interactive charts; and ii) a printing module that allows users to customize maps and export these to different formats (pdf, ppt, gif and jpg). New reference layers and an updated ship tracks layer have also been added. These improvements have been made to improve discoverability, enhance logistics coordination, identify geographic gaps in research/observation effort, and foster enhanced collaboration among the research community. Additionally, ARMAP can be used to demonstrate past, present, and future research effort supported by the U.S. Government.

  3. PhyloMap: an algorithm for visualizing relationships of large sequence data sets and its application to the influenza A virus genome

    Directory of Open Access Journals (Sweden)

    Martinetz Thomas

    2011-06-01

    Full Text Available Abstract Background Results of phylogenetic analysis are often visualized as phylogenetic trees. Such a tree can typically only include up to a few hundred sequences. When more than a few thousand sequences are to be included, analyzing the phylogenetic relationships among them becomes a challenging task. The recent frequent outbreaks of influenza A viruses have resulted in the rapid accumulation of corresponding genome sequences. Currently, there are more than 7500 influenza A virus genomes in the database. There are no efficient ways of representing this huge data set as a whole, thus preventing a further understanding of the diversity of the influenza A virus genome. Results Here we present a new algorithm, "PhyloMap", which combines ordination, vector quantization, and phylogenetic tree construction to give an elegant representation of a large sequence data set. The use of PhyloMap on influenza A virus genome sequences reveals the phylogenetic relationships of the internal genes that cannot be seen when only a subset of sequences are analyzed. Conclusions The application of PhyloMap to influenza A virus genome data shows that it is a robust algorithm for analyzing large sequence data sets. It utilizes the entire data set, minimizes bias, and provides intuitive visualization. PhyloMap is implemented in JAVA, and the source code is freely available at http://www.biochem.uni-luebeck.de/public/software/phylomap.html

  4. Lacrimal hypofunction as a new mechanism of dry eye in visual display terminal users.

    Directory of Open Access Journals (Sweden)

    Shigeru Nakamura

    Full Text Available BACKGROUND: Dry eye has shown a marked increase due to visual display terminal (VDT use. It remains unclear whether reduced blinking while focusing can have a direct deleterious impact on the lacrimal gland function. To address this issue that potentially affects the life quality, we conducted a large-scale epidemiological study of VDT users and an animal study. METHODOLOGY/PRINCIPAL FINDINGS: Cross sectional survey carried out in Japan. A total of 1025 office workers who use VDT were enrolled. The association between VDT work duration and changes in tear film status, precorneal tear stability, lipid layer status and tear secretion were analyzed. For the animal model study, the rat VDT user model, placing rats onto a balance swing in combination with exposure to an evaporative environment was used to analyze lacrimal gland function. There was no positive relationship between VDT working duration and change in tear film stability and lipid layer status. The odds ratio for decrease in Schirmer score, index of tear secretion, were significantly increased with VDT working year (P = 0.012 and time (P = 0.005. The rat VDT user model, showed chronic reduction of tear secretion and was accompanied by an impairment of the lacrimal gland function and morphology. This dysfunction was recovered when rats were moved to resting conditions without the swing. CONCLUSIONS/SIGNIFICANCE: These data suggest that lacrimal gland hypofunction is associated with VDT use and may be a critical mechanism for VDT-associated dry eye. We believe this to be the first mechanistic link to the pathogenesis of dry eye in office workers.

  5. Comparable mechanisms of working memory interference by auditory and visual motion in youth and aging

    OpenAIRE

    Mishra, Jyoti; Zanto, Theodore; Nilakantan, Aneesha; Gazzaley, Adam

    2013-01-01

    Intrasensory interference during visual working memory (WM) maintenance by object stimuli (such as faces and scenes), has been shown to negatively impact WM performance, with greater detrimental impacts of interference observed in aging. Here we assessed age-related impacts by intrasensory WM interference from lower-level stimulus features such as visual and auditory motion stimuli. We consistently found that interference in the form of ignored distractions and secondary task i nterruptions p...

  6. Influence of flap thickness on visual and refractive outcomes after laser in situ keratomileusis performed with a mechanical keratome.

    Science.gov (United States)

    Bansal, Alok S; Doherty, Terrence; Randleman, J Bradley; Stulting, R Doyle

    2010-05-01

    To study the effect of flap thickness on visual acuity and refractive outcomes after laser in situ keratomileusis (LASIK) using 2 blade types with a mechanical microkeratome. Emory Vision, Atlanta, Georgia, USA. This retrospective analysis was of LASIK cases performed between January 2005 and June 2006 using an Amadeus I microkeratome and an ML7090 CLB blade (blade A) or a Surepass blade (blade B). Outcomes analyzed included flap thickness, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), the enhancement rate, and surgical complications 3 months postoperatively. Two hundred sixty-three eyes of 153 patients were analyzed; blade A was used in 158 eyes and blade B, in 105 eyes. The mean flap thickness was significantly thinner with blade A than with blade B (107 microm +/- 12 [SD] versus 130 +/- 20 microm) (P .10), and there was no difference in the complication rates. Flap thickness did not affect visual or refractive outcomes with a mechanical microkeratome with either blade type. (c) 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  7. Solar Village in Malaysia – A Route Map for Financing Mechanism

    Directory of Open Access Journals (Sweden)

    Ahmad Nur Azfahani

    2016-01-01

    Full Text Available Malaysia’s development has been largely financed from its fossil fuels resources that come principally from the South China Sea. This has enabled electricity to be distributed equitably throughout society and improved the quality of life for people in Malaysia. However, the depletion of fossil fuel resources and the international conflict over South China Sea territorial ownership may leads to inadequacy of supply in the future, and may give direct impact to people in the rural areas. Malaysia’s greatest potential for solar energy comes from photovoltaics (PVs and the large roofs of village houses offer significant potential to contribute electricity both nationally and to the local communities. However, this technology is still unfamiliar to the people living in local villages due to the subsidised electricity by TNB and high capital costs of PV systems. This paper investigates whether establishing a “solar village” is feasible in Malaysia. Through a cost feasibility analysis, the potential of harnessing solar electricity for local villages in Malaysia has been demonstrated. A novel mechanism has been presented that allows rural households to own PV panels, rent the grid cables and to share surplus electricity within the community through a three (3 way financing routes map.

  8. Measures and visualization methods of map projection distortions with the use of “python matplotlib library” as an example

    Directory of Open Access Journals (Sweden)

    Pędzich Paweł

    2016-09-01

    Full Text Available The aim of the author of this article is to show the users of Geographical Information Systems how to present the distortions in a simple way. The intention of the author is also to popularize the knowledge in the scope of map projections and to inform the users of the maps that, despite all the advanced modern tools, an elimination of the problem, connected with the map projections and cartographical distortions occurring in them, has failed so far.

  9. Visualizing disease associations: graphic analysis of frequency distributions as a function of age using moving average plots (MAP) with application to Alzheimer's and Parkinson's disease.

    Science.gov (United States)

    Payami, Haydeh; Kay, Denise M; Zabetian, Cyrus P; Schellenberg, Gerard D; Factor, Stewart A; McCulloch, Colin C

    2010-01-01

    Age-related variation in marker frequency can be a confounder in association studies, leading to both false-positive and false-negative findings and subsequently to inconsistent reproducibility. We have developed a simple method, based on a novel extension of moving average plots (MAP), which allows investigators to inspect the frequency data for hidden age-related variations. MAP uses the standard case-control association data and generates a birds-eye view of the frequency distributions across the age spectrum; a picture in which one can see if, how, and when the marker frequencies in cases differ from that in controls. The marker can be specified as an allele, genotype, haplotype, or environmental factor; and age can be age-at-onset, age when subject was last known to be unaffected, or duration of exposure. Signature patterns that emerge can help distinguish true disease associations from spurious associations due to age effects, age-varying associations from associations that are uniform across all ages, and associations with risk from associations with age-at-onset. Utility of MAP is illustrated by application to genetic and epidemiological association data for Alzheimer's and Parkinson's disease. MAP is intended as a descriptive method, to complement standard statistical techniques. Although originally developed for age patterns, MAP is equally useful for visualizing any quantitative trait.

  10. Visualizing the mechanism that determines the critical current density in polycrystalline superconductors using time-dependent Ginzburg-Landau theory.

    OpenAIRE

    Carty, G. J.; Hampshire, D. P.

    2008-01-01

    In polycrystalline superconducting materials optimized for high critical current density (JC) in high magnetic fields, the mechanism that determines JC has long remained uncertain because of the complicated manner in which the fluxon-fluxon and fluxon-microstructure forces combine. In this work, the time-dependent Ginzburg-Landau equations are used to produce visualizations of fluxons at JC that show the disorder in the pinned part of the flux-line lattice and the motion of those fluxons alon...

  11. Mapping of ESE-1 subdomains required to initiate mammary epithelial cell transformation via a cytoplasmic mechanism

    Directory of Open Access Journals (Sweden)

    Tentler John J

    2011-08-01

    Full Text Available Abstract Background The ETS family transcription factor ESE-1 is often overexpressed in human breast cancer. ESE-1 initiates transformation of MCF-12A cells via a non-transcriptional, cytoplasmic process that is mediated by a unique 40-amino acid serine and aspartic acid rich (SAR subdomain, whereas, ESE-1's nuclear transcriptional property is required to maintain the transformed phenotype of MCF7, ZR-75-1 and T47D breast cancer cells. Results To map the minimal functional nuclear localization (NLS and nuclear export (NES signals, we fused in-frame putative NLS and NES motifs between GFP and the SAR domain. Using these GFP constructs as reporters of subcellular localization, we mapped a single NLS to six basic amino acids (242HGKRRR247 in the AT-hook and two CRM1-dependent NES motifs, one to the pointed domain (NES1: 102LCNCALEELRL112 and another to the DNA binding domain (DBD, (NES2: 275LWEFIRDILI284. Moreover, analysis of a putative NLS located in the DBD (316GQKKKNSN323 by a similar GFP-SAR reporter or by internal deletion of the DBD, revealed this sequence to lack NLS activity. To assess the role of NES2 in regulating ESE-1 subcellular localization and subsequent transformation potency, we site-specifically mutagenized NES2, within full-length GFP-ESE-1 and GFP-NES2-SAR reporter constructs. These studies show that site-specific mutation of NES2 completely abrogates ESE-1 transforming activity. Furthermore, we show that exclusive cytoplasmic targeting of the SAR domain is sufficient to initiate transformation, and we report that an intact SAR domain is required, since block mutagenesis reveals that an intact SAR domain is necessary to maintain its full transforming potency. Finally, using a monoclonal antibody targeting the SAR domain, we demonstrate that the SAR domain contains a region accessible for protein - protein interactions. Conclusions These data highlight that ESE-1 contains NLS and NES signals that play a critical role in

  12. A visualization and data-sharing tool for ecosystem service maps : Lessons learnt, challenges and the way forward

    NARCIS (Netherlands)

    Drakou, E. G.; Crossman, N.D.; Willemen, L.; Burkhard, B.; Palomo, I.; Maes, J.; Peedell, S.

    2015-01-01

    A plurality in methods, models, terminologies is used to assess, quantify, map and communicate ecosystem services (ES). The Thematic Working Groups on Mapping (TWG4) and Modeling ES (TWG5) of the Ecosystem Service Partnership (ESP), recent literature and expert workshops, have highlighted the need

  13. Management of the Lower St. Croix riverway: the application of cognitive visual mapping and social and resource assessment methods

    Science.gov (United States)

    Robert Becker; William Gates; Bernard J. Niemann Jr.

    1979-01-01

    This paper provides an overview of methods and results obtained from an extensive social and recreational carrying capacity study conducted for a National Scenic and Recreational Riverway - the Lower St. Croix. The paper also includes preliminary results and illustrations of a cognitive mapping technique for mapping scenic beauty. Over 1000 separate polygons were...

  14. Walkable self-overlapping virtual reality maze and map visualization demo: public virtual reality setup for asymmetric collaboration

    DEFF Research Database (Denmark)

    Serubugo, Sule; Skantarova, Denisa; Evers, Nicolaj

    2017-01-01

    This paper describes our demonstration of a walkable self-overlapping maze and its corresponding map to facilitate asymmetric collaboration for room-scale virtual reality setups in public places.......This paper describes our demonstration of a walkable self-overlapping maze and its corresponding map to facilitate asymmetric collaboration for room-scale virtual reality setups in public places....

  15. Hard-wired feed-forward visual mechanisms of the brain compensate for affine variations in object recognition.

    Science.gov (United States)

    Karimi-Rouzbahani, Hamid; Bagheri, Nasour; Ebrahimpour, Reza

    2017-05-04

    Humans perform object recognition effortlessly and accurately. However, it is unknown how the visual system copes with variations in objects' appearance and the environmental conditions. Previous studies have suggested that affine variations such as size and position are compensated for in the feed-forward sweep of visual information processing while feedback signals are needed for precise recognition when encountering non-affine variations such as pose and lighting. Yet, no empirical data exist to support this suggestion. We systematically investigated the impact of the above-mentioned affine and non-affine variations on the categorization performance of the feed-forward mechanisms of the human brain. For that purpose, we designed a backward-masking behavioral categorization paradigm as well as a passive viewing EEG recording experiment. On a set of varying stimuli, we found that the feed-forward visual pathways contributed more dominantly to the compensation of variations in size and position compared to lighting and pose. This was reflected in both the amplitude and the latency of the category separability indices obtained from the EEG signals. Using a feed-forward computational model of the ventral visual stream, we also confirmed a more dominant role for the feed-forward visual mechanisms of the brain in the compensation of affine variations. Taken together, our experimental results support the theory that non-affine variations such as pose and lighting may need top-down feedback information from higher areas such as IT and PFC for precise object recognition. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. Genetic fine mapping and genomic annotation defines causal mechanisms at type 2 diabetes susceptibility loci

    DEFF Research Database (Denmark)

    Gaulton, Kyle J; Ferreira, Teresa; Lee, Yeji

    2015-01-01

    We performed fine mapping of 39 established type 2 diabetes (T2D) loci in 27,206 cases and 57,574 controls of European ancestry. We identified 49 distinct association signals at these loci, including five mapping in or near KCNQ1. 'Credible sets' of the variants most likely to drive each distinct...

  17. Neural Mechanisms of Information Storage in Visual Short-Term Memory

    Science.gov (United States)

    Serences, John T.

    2016-01-01

    The capacity to briefly memorize fleeting sensory information supports visual search and behavioral interactions with relevant stimuli in the environment. Traditionally, studies investigating the neural basis of visual short term memory (STM) have focused on the role of prefrontal cortex (PFC) in exerting executive control over what information is stored and how it is adaptively used to guide behavior. However, the neural substrates that support the actual storage of content-specific information in STM are more controversial, with some attributing this function to PFC and others to the specialized areas of early visual cortex that initially encode incoming sensory stimuli. In contrast to these traditional views, I will review evidence suggesting that content-specific information can be flexibly maintained in areas across the cortical hierarchy ranging from early visual cortex to PFC. While the factors that determine exactly where content-specific information is represented are not yet entirely clear, recognizing the importance of task-demands and better understanding the operation of non-spiking neural codes may help to constrain new theories about how memories are maintained at different resolutions, across different timescales, and in the presence of distracting information. PMID:27668990

  18. Models Provide Specificity: Testing a Proposed Mechanism of Visual Working Memory Capacity Development

    Science.gov (United States)

    Simmering, Vanessa R.; Patterson, Rebecca

    2012-01-01

    Numerous studies have established that visual working memory has a limited capacity that increases during childhood. However, debate continues over the source of capacity limits and its developmental increase. Simmering (2008) adapted a computational model of spatial cognitive development, the Dynamic Field Theory, to explain not only the source…

  19. Contributions from cognitive neuroscience to understanding functional mechanisms of visual search.

    NARCIS (Netherlands)

    Humphreys, G.W.; Hodsoll, J.; Olivers, C.N.L.; Yoon, E.Y.

    2006-01-01

    We argue that cognitive neuroscience can contribute not only information about the neural localization of processes underlying visual search, but also information about the functional nature of these processes. First we present an overview of recent work on whether search for form - colour

  20. Mapping mass movement processes using terrestrial LIDAR: a swift mechanism for hazard and disaster risk assessment

    Science.gov (United States)

    Garnica-Peña, Ricardo; Murillo-García, Franny; Alcántara-Ayala, Irasema

    2014-05-01

    The impact of disasters associated with mass movement processes has increased in the past decades. Either triggered by earthquakes, volcanic activity or rainfall, mass movement processes have affected people, infrastructure, economic activities and the environment in different parts of the world. Extensive damage is particularly linked to rainfall induced landslides due to the occurrence of tropical storms, hurricanes, and the combination of different meteorological phenomenon on exposed vulnerable communities. Therefore, landslide susceptibility analysis, hazard and risk assessments are considered as significant mechanisms to lessen the impact of disasters. Ideally, these procedures ought to be carried out before disasters take place. However, under intense or persistent periods of rainfall, the evaluation of potentially unstable slopes becomes a critical issue. Such evaluations are constrained by the availability of resources, capabilities and scientific and technological tools. Among them, remote sensing has proved to be a valuable tool to evaluate areas affected by mass movement processes during the post-disaster stage. Nonetheless, the high cost of imagery acquisition inhibits their wide use. High resolution topography field surveys consequently, turn out to be an essential approach to address landslide evaluation needs. In this work, we present the evaluation and mapping of a series of mass movement processes induced by hurricane Ingrid in September, 2013, in Teziutlán, Puebla, México, a municipality situated 265 km Northeast of Mexico City. Geologically, Teziutlán is characterised by the presence, in the North, of siltstones and conglomerates of the Middle Jurassic, whereas the central and Southern sectors consist of volcanic deposits of various types: andesitic tuffs of Tertiary age, and basalts, rhyolitic tuffs and ignimbrites from the Quaternary. Major relief structures are formed by the accumulation of volcanic material; lava domes, partially buried

  1. Using Self-Organizing Neural Network Map Combined with Ward's Clustering Algorithm for Visualization of Students' Cognitive Structural Models about Aliveness Concept.

    Science.gov (United States)

    Yorek, Nurettin; Ugulu, Ilker; Aydin, Halil

    2016-01-01

    We propose an approach to clustering and visualization of students' cognitive structural models. We use the self-organizing map (SOM) combined with Ward's clustering to conduct cluster analysis. In the study carried out on 100 subjects, a conceptual understanding test consisting of open-ended questions was used as a data collection tool. The results of analyses indicated that students constructed the aliveness concept by associating it predominantly with human. Motion appeared as the most frequently associated term with the aliveness concept. The results suggest that the aliveness concept has been constructed using anthropocentric and animistic cognitive structures. In the next step, we used the data obtained from the conceptual understanding test for training the SOM. Consequently, we propose a visualization method about cognitive structure of the aliveness concept.

  2. Benthic Habitat Type Maps of the Oahu Island 2000 - Prepared by Visual Interpretation from Remote Sensing Imagery Collected by NOAA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Twenty-four habitat and zone maps. This project is a cooperative effort between the National Ocean Service, National Centers for Coastal Ocean Science, Center for...

  3. Benthic Habitat Type Maps of the Maui Island 2000 - Prepared by Visual Interpretation from Remote Sensing Imagery Collected by NOAA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Thirteen habitat and zone maps. This project is a cooperative effort between the National Ocean Service, National Centers for Coastal Ocean Science, Center for...

  4. Benthic Habitat Type Maps of the Niihau Island 2000 - Prepared by Visual Interpretation from Remote Sensing Imagery Collected by NOAA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Four habitat and zone maps. This project is a cooperative effort between the National Ocean Service, National Centers for Coastal Ocean Science, Center for Coastal...

  5. An Efficient Interception Mechanism Against Cheating In Visual Cryptography With Non Pixel Expansion Of Images

    Directory of Open Access Journals (Sweden)

    Linju P.S

    2015-08-01

    Full Text Available Visual cryptography is a technique of cryptography in which secret images are divided into multiple shares and are distributed to different entities. Each secret can be reconstructed by superimposing these shares using different operations. Common traditional drawbacks of all existing methods are pixel expansion and noise at output. Another major issues that can occur in existing visual cryptography systems are Cheating between share holders and Share holders cheating owner. In order to overcome these limitations sealing algorithm is used with two applications of VC such as MIVC and EVC. Here two secret images can be send at the same time by converting them to halftone representations which in turn are partitioned as three shares in total.

  6. When Multimedia Doesn’t Work: An Assessment of Visualization Modules for Learning Enhancement in Mechanics

    Science.gov (United States)

    2000-06-01

    learning preference or personality type. Learning preferences were determined from an assessment method known as VARK , while the personality type...of this effort to enhance engineering education is focused in the following areas: learning styles , multimedia visualization/simulation, hands-on...Experiences to Enhance Learning of Design: Effectiveness in a Redesign Context When Correlated with MBTI and VARK Types,” Accepted for the ASEE Annual

  7. An Evolutionarily Conserved Mechanism for Activity-Dependent Visual Circuit Development

    Science.gov (United States)

    Pratt, Kara G.; Hiramoto, Masaki; Cline, Hollis T.

    2016-01-01

    Neural circuit development is an activity-dependent process. This activity can be spontaneous, such as the retinal waves that course across the mammalian embryonic retina, or it can be sensory-driven, such as the activation of retinal ganglion cells (RGCs) by visual stimuli. Whichever the source, neural activity provides essential instruction to the developing circuit. Indeed, experimentally altering activity has been shown to impact circuit development and function in many different ways and in many different model systems. In this review, we contemplate the idea that retinal waves in amniotes, the animals that develop either in ovo or utero (namely reptiles, birds and mammals) could be an evolutionary adaptation to life on land, and that the anamniotes, animals whose development is entirely external (namely the aquatic amphibians and fish), do not display retinal waves, most likely because they simply don’t need them. We then review what is known about the function of both retinal waves and visual stimuli on their respective downstream targets, and predict that the experience-dependent development of the tadpole visual system is a blueprint of what will be found in future studies of the effects of spontaneous retinal waves on instructing development of retinorecipient targets such as the superior colliculus (SC) and the lateral geniculate nucleus. PMID:27818623

  8. An Evolutionarily Conserved Mechanism for Activity-dependent Visual Circuit Development

    Directory of Open Access Journals (Sweden)

    Kara Geo Pratt

    2016-10-01

    Full Text Available Neural circuit development is an activity-dependent process. This activity can be spontaneous, such as the retinal waves that course across the mammalian embryonic retina, or it can be sensory-driven, such as the activation of retinal ganglion cells by visual stimuli. Whichever the source, neural activity provides essential instruction to the developing circuit. Indeed, experimentally altering activity has been shown to impact circuit development and function in many different ways and in many different model systems. In this review we contemplate the idea that retinal waves in amniotes, the animals that develop either in ovo or utero (namely reptiles, birds, mammals could be an evolutionary adaptation to life on land, and that the anamniotes, animals whose development is entirely external (namely the aquatic amphibians and fish, do not display retinal waves, most likely because they simply don’t need them. We then review what is known about the function of both retinal waves and visual stimuli on their respective downstream targets, and predict that the experience-dependent development of the tadpole visual system is a blueprint of what will be found in future studies of the effects of spontaneous retinal waves on instructing development of retinorecipient targets such as the superior colliculus and the lateral geniculate nucleus.

  9. Pharmacological Mechanisms of Cortical Enhancement Induced by the Repetitive Pairing of Visual/Cholinergic Stimulation.

    Directory of Open Access Journals (Sweden)

    Jun-Il Kang

    Full Text Available Repetitive visual training paired with electrical activation of cholinergic projections to the primary visual cortex (V1 induces long-term enhancement of cortical processing in response to the visual training stimulus. To better determine the receptor subtypes mediating this effect the selective pharmacological blockade of V1 nicotinic (nAChR, M1 and M2 muscarinic (mAChR or GABAergic A (GABAAR receptors was performed during the training session and visual evoked potentials (VEPs were recorded before and after training. The training session consisted of the exposure of awake, adult rats to an orientation-specific 0.12 CPD grating paired with an electrical stimulation of the basal forebrain for a duration of 1 week for 10 minutes per day. Pharmacological agents were infused intracortically during this period. The post-training VEP amplitude was significantly increased compared to the pre-training values for the trained spatial frequency and to adjacent spatial frequencies up to 0.3 CPD, suggesting a long-term increase of V1 sensitivity. This increase was totally blocked by the nAChR antagonist as well as by an M2 mAChR subtype and GABAAR antagonist. Moreover, administration of the M2 mAChR antagonist also significantly decreased the amplitude of the control VEPs, suggesting a suppressive effect on cortical responsiveness. However, the M1 mAChR antagonist blocked the increase of the VEP amplitude only for the high spatial frequency (0.3 CPD, suggesting that M1 role was limited to the spread of the enhancement effect to a higher spatial frequency. More generally, all the drugs used did block the VEP increase at 0.3 CPD. Further, use of each of the aforementioned receptor antagonists blocked training-induced changes in gamma and beta band oscillations. These findings demonstrate that visual training coupled with cholinergic stimulation improved perceptual sensitivity by enhancing cortical responsiveness in V1. This enhancement is mainly mediated by n

  10. Visualizing the mechanism that determines the critical current density in polycrystalline superconductors using time-dependent Ginzburg-Landau theory

    Science.gov (United States)

    Carty, George J.; Hampshire, Damian P.

    2008-05-01

    In polycrystalline superconducting materials optimized for high critical current density (JC) in high magnetic fields, the mechanism that determines JC has long remained uncertain because of the complicated manner in which the fluxon-fluxon and fluxon-microstructure forces combine. In this work, the time-dependent Ginzburg-Landau equations are used to produce visualizations of fluxons at JC that show the disorder in the pinned part of the flux-line lattice and the motion of those fluxons along grain boundaries that cause dissipation. Calculated values of JC are consistent with experimental data.

  11. Neural mechanisms of repetition priming of familiar and globally unfamiliar visual objects.

    Science.gov (United States)

    Soldan, Anja; Habeck, Christian; Gazes, Yunglin; Stern, Yaakov

    2010-07-09

    Functional magnetic resonance imaging (fMRI) studies have shown that repetition priming of visual objects is typically accompanied by a reduction in activity for repeated compared to new stimuli (repetition suppression). However, the spatial distribution and direction (suppression vs. enhancement) of neural repetition effects can depend on the pre-experimental familiarity of stimuli. The first goal of this study was to further probe the link between repetition priming and repetition suppression/enhancement for visual objects and how this link is affected by stimulus familiarity. A second goal was to examine whether priming of familiar and unfamiliar objects following a single stimulus repetition is supported by the same processes as priming following multiple repetitions within the same task. In this endeavor, we examined both between and within-subject correlations between priming and fMRI repetition effects for familiar and globally unfamiliar visual objects during the first and third repetitions of the stimuli. We included reaction time of individual trials as a linear regressor to identify brain regions whose repetition effects varied with response facilitation on a trial-by-trial basis. The results showed that repetition suppression in bilateral fusiform gyrus, was selectively correlated with priming of familiar objects that had been repeated once, likely reflecting facilitated perceptual processing or the sharpening of perceptual representations. Priming during the third repetition was correlated with repetition suppression in prefrontal and parietal areas for both familiar and unfamiliar stimuli, possibly reflecting a shift from top-down controlled to more automatic processing that occurs for both item types. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  12. Star Maps, Planispheres, and Celestial Calendars : Engaging Students, Educators, and Communities with Multicultural STEM/STEAM Visual Resources

    Science.gov (United States)

    Lee, Annette S.; Wilson, William; Tibbetts, Jeffrey; Gawboy, Carl

    2017-06-01

    Aim:Designed by A. Lee, the Native Skywatchers initiative seeks to remember and revitalize indigenous star and earth knowledge, promoting the native voice as the lead voice. The overarching goal of Native Skywatchers is to communicate the knowledge that indigenous people practiced a sustainable way of living and sustainable engineering through a living and participatory relationship with the above and below, sky and earth. We aim to improve current inequities in education for native young people, to inspire increased cultural pride, and promote community wellness. We hope to inspire all participants towards a rekindling of the excitement and curiosity that causes us to look up at the sky in wonder generation after generation.Results:Presented here are several Native Skywatchers initiatives under the broad categories of: 1.) star maps, 2.) planispheres, and 3.) celestial calendars. In 2012 two indigenous star maps were created: the Ojibwe Giizhig Anung Masinaaigan-Ojibwe Sky Star Map (A. Lee, W. Wilson, C. Gawboy), and the D(L)akota star map, Makoce Wicanhpi Wowapi (A. Lee, J. Rock). More recently, a collaboration with W. Buck, science educator, at the Manitoba First Nations Resource Centre (MFNRC), in Winnipeg, Manitoba produced a third indigenous star map: Ininew Achakos Masinikan-Cree Star Map Book. Having star maps that are rooted in astronomical knowledge and cultural wisdoms has allowed communities multiple and ongoing opportunities for inclusive culture-based STEM learning. Next, planispheres were created based on the indigenous star maps. A learning and teaching hands-on tool, the planispheres, help partakers understand the patterns of motion in the night sky in addition to simply identifying the constellations. Most recently, calendar-paintings of the yearly motion of the Sun, the phases of the Moon, and the Venus-year have all been added to the growing list of Native Skywatchers resources. Working collaboratively with regional schools, educators, museums

  13. A COGNITIVE APPROACH TO CORPORATE GOVERNANCE: A VISUALIZATION TEST OF MENTAL MODELS WITH THE COGNITIVE MAPPING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Garoui NASSREDDINE

    2012-01-01

    Full Text Available The idea of this paper is to determine the mental models of actors in the fi rm with respect to the cognitive approach of corporate governance. The paper takes a corporate governance perspective, discusses mental models and uses the cognitive map to view the diagrams showing the ways of thinking and the conceptualization of the cognitive approach. In addition, it employs a cognitive mapping technique. Returning to the systematic exploration of grids for each actor, it concludes that there is a balance of concepts expressing their cognitive orientation.

  14. Standardization of seismic tomographic models and earthquake focal mechanisms data sets based on web technologies, visualization with keyhole markup language

    Science.gov (United States)

    Postpischl, Luca; Danecek, Peter; Morelli, Andrea; Pondrelli, Silvia

    2011-01-01

    We present two projects in seismology that have been ported to web technologies, which provide results in Keyhole Markup Language (KML) visualization layers. These use the Google Earth geo-browser as the flexible platform that can substitute specialized graphical tools to perform qualitative visual data analyses and comparisons. The Network of Research Infrastructures for European Seismology (NERIES) Tomographic Earth Model Repository contains data sets from over 20 models from the literature. A hierarchical structure of folders that represent the sets of depths for each model is implemented in KML, and this immediately results into an intuitive interface for users to navigate freely and to compare tomographic plots. The KML layer for the European-Mediterranean Regional Centroid-Moment Tensor Catalog displays the focal mechanism solutions or moderate-magnitude Earthquakes from 1997 to the present. Our aim in both projects was to also propose standard representations of scientific data sets. Here, the general semantic approach of an XML framework has an important impact that must be further explored, although we find the KML syntax to more emphasis on aspects of detailed visualization. We have thus used, and propose the use of, Javascript Object Notation (JSON), another semantic notation that stems from the web-development community that provides a compact, general-purpose, data-exchange format.

  15. Laser Ultrasonic System for Surface Crack Visualization in Dissimilar Welds of Control Rod Drive Mechanism Assembly of Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Yun-Shil Choi

    2014-01-01

    Full Text Available In this paper, we propose a J-groove dissimilar weld crack visualization system based on ultrasonic propagation imaging (UPI technology. A full-scale control rod drive mechanism (CRDM assembly specimen was fabricated to verify the proposed system. An ultrasonic sensor was contacted at one point of the inner surface of the reactor vessel head part of the CRDM assembly. Q-switched laser beams were scanned to generate ultrasonic waves around the weld bead. The localization and sizing of the crack were possible by ultrasonic wave propagation imaging. Furthermore, ultrasonic spectral imaging unveiled frequency components of damage-induced waves, while wavelet-transformed ultrasonic propagation imaging enhanced damage visibility by generating a wave propagation video focused on the frequency component of the damage-induced waves. Dual-directional anomalous wave propagation imaging with adjacent wave subtraction was also developed to enhance the crack visibility regardless of crack orientation and wave propagation direction. In conclusion, the full-scale specimen test demonstrated that the multiple damage visualization tools are very effective in the visualization of J-groove dissimilar weld cracks.

  16. Metadata Mapper: a web service for mapping data between independent visual analysis components, guided by perceptual rules

    Science.gov (United States)

    Rogowitz, Bernice E.; Matasci, Naim

    2011-03-01

    The explosion of online scientific data from experiments, simulations, and observations has given rise to an avalanche of algorithmic, visualization and imaging methods. There has also been enormous growth in the introduction of tools that provide interactive interfaces for exploring these data dynamically. Most systems, however, do not support the realtime exploration of patterns and relationships across tools and do not provide guidance on which colors, colormaps or visual metaphors will be most effective. In this paper, we introduce a general architecture for sharing metadata between applications and a "Metadata Mapper" component that allows the analyst to decide how metadata from one component should be represented in another, guided by perceptual rules. This system is designed to support "brushing [1]," in which highlighting a region of interest in one application automatically highlights corresponding values in another, allowing the scientist to develop insights from multiple sources. Our work builds on the component-based iPlant Cyberinfrastructure [2] and provides a general approach to supporting interactive, exploration across independent visualization and visual analysis components.

  17. Google Earth Mapping Exercises for Structural Geology Students--A Promising Intervention for Improving Penetrative Visualization Ability

    Science.gov (United States)

    Giorgis, Scott

    2015-01-01

    Three-dimensional thinking skills are extremely useful for geoscientists, and at the undergraduate level, these skills are often emphasized in structural geology courses. Google Earth is a powerful tool for visualizing the three-dimensional nature of data collected on the surface of Earth. The results of a 5 y pre- and posttest study of the…

  18. Construction of Cognitive Maps to Improve E-Book Reading and Navigation

    Science.gov (United States)

    Li, Liang-Yi; Chen, Gwo-Dong; Yang, Sheng-Jie

    2013-01-01

    People have greater difficulty reading academic textbooks on screen than on paper. One notable problem is that they cannot construct an effective cognitive map because of the lack of contextual information cues and ineffective navigational mechanisms in e-books. To support the construction of cognitive maps, this paper proposes the visual cue map,…

  19. Does Visualization Enhance Complex Problem Solving? The Effect of Causal Mapping on Performance in the Computer-Based Microworld Tailorshop

    Science.gov (United States)

    Öllinger, Michael; Hammon, Stephanie; von Grundherr, Michael; Funke, Joachim

    2015-01-01

    Causal mapping is often recognized as a technique to support strategic decisions and actions in complex problem situations. Such drawing of causal structures is supposed to particularly foster the understanding of the interaction of the various system elements and to further encourage holistic thinking. It builds on the idea that humans make use…

  20. Ontology-aided annotation, visualization and generalization of geological time scale information from online geological map services

    NARCIS (Netherlands)

    Ma, Marshal; Ma, X.; Carranza, E.J.M; Wu, C.; van der Meer, F.D.

    2012-01-01

    Geological maps are increasingly published and shared online, whereas tools and services supporting information retrieval and knowledge discovery are underdeveloped. In this study, we developed an ontology of geological time scale by using a Resource Description Framework model to represent the

  1. Ontology-aided annotation, visualization and generalization of geological time-scale information from online geological map services

    NARCIS (Netherlands)

    Ma, X.; Carranza, E.J.M.; Wu, C.; Meer, F.D. van der

    2012-01-01

    Geological maps are increasingly published and shared online, whereas tools and services supporting information retrieval and knowledge discovery are underdeveloped. In this study, we developed an ontology of geological time scale by using a RDF (Resource Description Framework) model to represent

  2. [Visualizing Research Lines in Public Health: An analysis Based on Bibliometric Maps Applied to the Revista Española de Salud Pública (2006-2015)].

    Science.gov (United States)

    Gálvez, Carmen

    2016-12-01

    Identifying research lines is essential to understand the knowledge structure of a scientific domain. The aim of this study was to identify the main research topics of within the domain of public health, in the Revista Española de Saslud Pública during 2006-2015. Original articles included in the Social Sciences Citation Index (SSCI) database, available online through the Web of Science (WoS), were selected. The analysis units used were the keywords, KeyWords Plus (KW+), extracted automatically by SSCI. With KW+ obtained bibliometric, maps were created using a methodology based on the combination of co-word analysis, co-word analysis, clustering techniques and visualization techniques. We analyzed 512 documents, of which 176 KW+ were obtained with a frequency greater than or equal to 3. The results were bidimensional bibliometric maps with thematic groupings of KW+, representing the main research fronts: i) epidemiology, risk control programs disease and, in general, service organization and health policies; ii) infectious diseases, principally HIV; iii) a progressive increase in several lines interrelated with cardiovascular diseases (CVD); iv) a line multidimensional dedicated to different aspects associated to the quality of life related to health (HRQoL); and v) an emerging line linked to binge drinking. For the multidisciplinary and multidimensional nature of public health, the construction of bibliometric maps is an appropriate methodology to understand the knowledge structure of this scientific domain.

  3. The mechanical and photoelastic properties of 3D printable stress-visualized materials

    National Research Council Canada - National Science Library

    Li Wang; Yang Ju; Heping Xie; Guowei Ma; Lingtao Mao; Kexin He

    2017-01-01

    ...- or construction-related disturbances of deeply buried rock masses. However, concerns have been raised about the similitude between the mechanical behaviours of the printed model and its prototype rock mass...

  4. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.

    1985-01-01

    This book consists of essays covering issues in visual cognition presenting experimental techniques from cognitive psychology, methods of modeling cognitive processes on computers from artificial intelligence, and methods of studying brain organization from neuropsychology. Topics considered include: parts of recognition; visual routines; upward direction; mental rotation, and discrimination of left and right turns in maps; individual differences in mental imagery, computational analysis and the neurological basis of mental imagery: componental analysis.

  5. Direct visualization of mechanical beats by means of an oscillating smartphone

    CERN Document Server

    Giménez, Marcos H; Monsoriu, Juan A

    2016-01-01

    The resonance phenomenon is widely known from Physics courses. Qualitatively speaking, it takes place in a driven oscillating system whenever the driven frequency approaches the natural frequency. It is when the amplitude of the oscillations become maximal. Very closely related to this phenomenon, there is another which is very surprising too. It takes place when the driven and natural frequencies of the system are slightly different and interfere constructively and destructively, forming the so called beats. The frequency of the beats is just the difference of the interfering waves frequencies. Beats are very noticeable in acoustic systems. We all have probably perceived them in the form of periodic ups and downs in the sound intensity volume. There are several works in this journal on visualizing the beats in acoustic systems. For instance, the microphone and the speaker of two mobile devices were used in previous work to analyze the acoustic beat produced by two signals of close frequencies. The formation ...

  6. The Mechanic Eye: North American Visual Poetry in the Digital Age

    Directory of Open Access Journals (Sweden)

    Maria Goicoechea de Jorge

    2012-07-01

    Full Text Available http://dx.doi.org/10.5007/1807-9288.2012v8n1p78 This paper offers a revision of North American visual poetry from the contemporary perspective of the digital revolution. From the Native American chants to the digital poetry found on the Web, it will explore the internal drives of this sort of poetic manifestations that have endured through different time periods, aesthetic currents and cultural functions despite the various mediums employed for their production and dissemination. Digital poetry nourishes itself from previous literary traditions as well as from the multimedia convergence favored by the digital medium. We will analyze these influences, and the new reading strategies required to contextualize and make sense out of the digital work of poetry. As readers and writers reorganize their reading pacts, researchers of literature face a new challenge: the polymorphic and metamorphosing liquid text made possible by the digital language

  7. Deformation Mechanism Map of Cu/Nb Nanoscale Metallic Multilayers as a Function of Temperature and Layer Thickness

    Science.gov (United States)

    Snel, J.; Monclús, M. A.; Castillo-Rodríguez, M.; Mara, N.; Beyerlein, I. J.; Llorca, J.; Molina-Aldareguía, J. M.

    2017-11-01

    The mechanical properties and deformation mechanisms of Cu/Nb nanoscale metallic multilayers (NMMs) manufactured by accumulative roll bonding are studied at 25°C and 400°C. Cu/Nb NMMs with individual layer thicknesses between 7 nm and 63 nm were tested by in situ micropillar compression inside a scanning electron microscope. Yield strength, strain-rate sensitivities and activation volumes were obtained from the pillar compression tests. The deformed micropillars were examined under scanning and transmission electron microscopy in order to examine the deformation mechanisms active for different layer thicknesses and temperatures. The analysis suggests that room temperature deformation was determined by dislocation glide at larger layer thicknesses and interface-related mechanisms at the thinner layer thicknesses. The high-temperature compression tests, in contrast, revealed superior thermo-mechanical stability and strength retention for the NMMs with larger layer thicknesses with deformation controlled by dislocation glide. A remarkable transition in deformation mechanism occurred as the layer thickness decreased, to a deformation response controlled by diffusion processes along the interfaces, which resulted in temperature-induced softening. A deformation mechanism map, in terms of layer thickness and temperature, is proposed from the results obtained in this investigation.

  8. Microstructure and Mechanical Properties of Ti Cold-Spray Splats Determined by Electron Channeling Contrast Imaging and Nanoindentation Mapping.

    Science.gov (United States)

    Goldbaum, Dina; Chromik, Richard R; Brodusch, Nicolas; Gauvin, Raynald

    2015-06-01

    Cold spray is a thermo-mechanical process where the velocity of the sprayed particles affects the deformation, bonding, and mechanical properties of the deposited material, in the form of splats or coatings. At high strain rates, the impact stresses are converted into heat, a phenomenon known as adiabatic shear, which leads to grain re-crystallization. Grain re-crystallization and growth are shown to have a direct impact on the mechanical properties of the cold-sprayed material. The present study ties the microstructural features within the cold-sprayed Ti splats and the substrate to the bonding mechanism and mechanical properties. High-resolution electron channeling contrast imaging, electron backscatter diffraction mapping, and nanoindentation were used to correlate the microstructure to the mechanical properties distribution within the titanium cold-spray splats. The formation of nanograins was observed at the titanium splat/substrate interface and contributed to metallurgical bonding. An increase in grain re-crystallization within the splat and substrate materials was observed with pre-heating of the substrate. In the substrate material, the predominant mechanism of deformation was twinning. A good relationship was found between the hardness and distribution of the twins within the substrate and the size distribution of the re-crystallized grains within the splats.

  9. Quantum Mechanics/Molecular Mechanics Free Energy Maps and Nonadiabatic Simulations for a Photochemical Reaction in DNA: Cyclobutane Thymine Dimer.

    Science.gov (United States)

    Mendieta-Moreno, Jesús I; Trabada, Daniel G; Mendieta, Jesús; Lewis, James P; Gómez-Puertas, Paulino; Ortega, José

    2016-11-03

    The absorption of ultraviolet radiation by DNA may result in harmful genetic lesions that affect DNA replication and transcription, ultimately causing mutations, cancer, and/or cell death. We analyze the most abundant photochemical reaction in DNA, the cyclobutane thymine dimer, using hybrid quantum mechanics/molecular mechanics (QM/MM) techniques and QM/MM nonadiabatic molecular dynamics. We find that, due to its double helix structure, DNA presents a free energy barrier between nonreactive and reactive conformations leading to the photolesion. Moreover, our nonadiabatic simulations show that most of the photoexcited reactive conformations return to standard B-DNA conformations after an ultrafast nonradiative decay to the ground state. This work highlights the importance of dynamical effects (free energy, excited-state dynamics) for the study of photochemical reactions in biological systems.

  10. Visualizing and communicating climate change using the ClimateWizard: decision support and education through web-based analysis and mapping

    Science.gov (United States)

    Girvetz, E. H.; Zganjar, C.; Raber, G. T.; Maurer, E. P.; Duffy, P.

    2009-12-01

    Virtually all fields of study and parts of society—from ecological science and nature conservation, to global development, multinational corporations, and government bodies—need to know how climate change has and may impact specific locations of interest. Our ability to respond to climate change depends on having convenient tools that make past and projected climate trends available to planners, managers, scientists and the general public, at scales ranging from global to local scales. Web-mapping applications provide an effective platform for communicating climate change impacts in specific geographic areas of interest to the public. Here, we present one such application, the ClimateWizard, that allows users to analyze, visualize and explore climate change maps for specific geographic areas of interest throughout the world (http://ClimateWizard.org). Built on Web 2.0 web-services (SOAP), Google Maps mash-up, and cloud computing technologies, the ClimateWizard analyzes large databases of climate information located on remote servers to create synthesized information and useful products tailored to geographic areas of interest (e.g. maps, graphs, tables, GIS layers). We demonstrate how the ClimateWizard can be used to assess projected changes to temperature and precipitation across all states in the contiguous United States and all countries of the world using statistically downscaled general circulation models from the CMIP3 dataset. We then go on to show how ClimateWizard can be used to analyze changes to other climate related variables, such as moisture stress and water production. Finally, we discuss how this tool can be adapted to develop a wide range of web-based tools that are targeted at informing specific audiences—from scientific research and natural resource management, to K-12 and higher education—about how climate change may affect different aspects of human and natural systems.

  11. How information visualization novices construct visualizations.

    Science.gov (United States)

    Grammel, Lars; Tory, Melanie; Storey, Margaret-Anne

    2010-01-01

    It remains challenging for information visualization novices to rapidly construct visualizations during exploratory data analysis. We conducted an exploratory laboratory study in which information visualization novices explored fictitious sales data by communicating visualization specifications to a human mediator, who rapidly constructed the visualizations using commercial visualization software. We found that three activities were central to the iterative visualization construction process: data attribute selection, visual template selection, and visual mapping specification. The major barriers faced by the participants were translating questions into data attributes, designing visual mappings, and interpreting the visualizations. Partial specification was common, and the participants used simple heuristics and preferred visualizations they were already familiar with, such as bar, line and pie charts. We derived abstract models from our observations that describe barriers in the data exploration process and uncovered how information visualization novices think about visualization specifications. Our findings support the need for tools that suggest potential visualizations and support iterative refinement, that provide explanations and help with learning, and that are tightly integrated into tool support for the overall visual analytics process.

  12. Anticipatory attentional suppression of visual features indexed by oscillatory alpha-band power increases: a high-density electrical mapping study.

    Science.gov (United States)

    Snyder, Adam C; Foxe, John J

    2010-03-17

    Retinotopically specific increases in alpha-band ( approximately 10 Hz) oscillatory power have been strongly implicated in the suppression of processing for irrelevant parts of the visual field during the deployment of visuospatial attention. Here, we asked whether this alpha suppression mechanism also plays a role in the nonspatial anticipatory biasing of feature-based attention. Visual word cues informed subjects what the task-relevant feature of an upcoming visual stimulus (S2) was, while high-density electroencephalographic recordings were acquired. We examined anticipatory oscillatory activity in the Cue-to-S2 interval ( approximately 2 s). Subjects were cued on a trial-by-trial basis to attend to either the color or direction of motion of an upcoming dot field array, and to respond when they detected that a subset of the dots differed from the majority along the target feature dimension. We used the features of color and motion, expressly because they have well known, spatially separated cortical processing areas, to distinguish shifts in alpha power over areas processing each feature. Alpha power from dorsal regions increased when motion was the irrelevant feature (i.e., color was cued), and alpha power from ventral regions increased when color was irrelevant. Thus, alpha-suppression mechanisms appear to operate during feature-based selection in much the same manner as has been shown for space-based attention.

  13. Cognitive Mechanisms underlying visual perspective taking in typical and ASC children.

    Science.gov (United States)

    Pearson, Amy; Marsh, Lauren; Ropar, Danielle; Hamilton, Antonia

    2016-01-01

    Previous research has suggested that people with Autism Spectrum Conditions (ASC) may have difficulty with visual perspective taking (VPT) but it is not clear how this relates to different strategies that can be used in perspective taking tasks. The current study examined VPT in 30 children with autism and 30 verbal mental age matched typical children, in comparison to mental rotation (MR) abilities and body representation abilities. Using a similar paradigm to Hamilton, Brindley, and Frith [2009] all children completed three tasks: a VPT task in which children decided what a toy on a table would look like from a different points of view; a MR task in which the child decided what a toy would look like after it had been rotated; and a body posture matching task, in which children matched pictures of a body shown from different viewpoints. Results showed that children with ASC performed better than the typically developing children on the MR task, and at a similar level on the VPT task and body matching task. Importantly, in the typical children VPT performance was predicted by performance on the body matching task, whereas in the ASC children VPT performance was predicted by MR ability. These findings suggest that differences in VPT in ASC may be explained by the use of a spatial rotation strategy rather than the embodied egocentric transformation strategy used by typical children. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

  14. Learning to Associate Auditory and Visual Stimuli: Behavioral and Neural Mechanisms

    Science.gov (United States)

    Altieri, Nicholas; Stevenson, Ryan; Wallace, Mark T.; Wenger, Michael J.

    2014-01-01

    The ability to effectively combine sensory inputs across modalities is vital for acquiring a unified percept of events. For example, watching a hammer hit a nail while simultaneously identifying the sound as originating from the event requires the ability to identify spatio-temporal congruencies and statistical regularities. In this study, we applied a reaction time (RT) and hazard function measure known as capacity (e.g., Townsend and Ashby, 1978) to quantify the extent to which observers learn paired associations between simple auditory and visual patterns in a model theoretic manner. As expected, results showed that learning was associated with an increase in accuracy, but more significantly, an increase in capacity. The aim of this study was to associate capacity measures of multisensory learning, with neural based measures, namely mean Global Field Power (GFP). We observed a co-variation between an increase in capacity, and a decrease in GFP amplitude as learning occurred. This suggests that capacity constitutes a reliable behavioral index of efficient energy expenditure in the neural domain. PMID:24276220

  15. Accelerating Our Understanding of Supernova Explosion Mechanism via Simulations and Visualizations with GenASiS

    Energy Technology Data Exchange (ETDEWEB)

    Budiardja, R. D. [University of Tennessee, Knoxville (UTK); Cardall, Christian Y [ORNL; Endeve, Eirik [ORNL

    2015-01-01

    Core-collapse supernovae are among the most powerful explosions in the Universe, releasing about 1053 erg of energy on timescales of a few tens of seconds. These explosion events are also responsible for the production and dissemination of most of the heavy elements, making life as we know it possible. Yet exactly how they work is still unresolved. One reason for this is the sheer complexity and cost of a self-consistent, multi-physics, and multi-dimensional core-collapse supernova simulation, which is impractical, and often impossible, even on the largest supercomputers we have available today. To advance our understanding we instead must often use simplified models, teasing out the most important ingredients for successful explosions, while helping us to interpret results from higher fidelity multi-physics models. In this paper we investigate the role of instabilities in the core-collapse supernova environment. We present here simulation and visualization results produced by our code GenASiS.

  16. Implications of the visual appearance of ball lightning for luminosity mechanisms

    Science.gov (United States)

    Stephan, Karl D.

    2012-11-01

    Observations of ball lightning continue to pose one of the more difficult unsolved problems in atmospheric physics. Lack of quantitative data has frustrated attempts to explain how the objects emit light. We examine three leading theories for the immediate cause of light emission: excitation of plasma, small hot individual particles suspended in air, and hot fractal clusters of small particles. Using radiative transport theory, we find quantitative values for the ranges of particle density and temperature required to produce luminous intensities consistent with the bulk of reported observations, as well as estimates of power requirements for each mechanism. We conclude that all of these mechanisms are consistent with many ball-lightning observations, and that more than one of them may be involved in the luminosity of ball lightning.

  17. 3D Visualization of Earthquake Focal Mechanisms Using ArcScene

    Science.gov (United States)

    Labay, Keith A.; Haeussler, Peter J.

    2007-01-01

    We created a new tool, 3D Focal Mechanisms (3DFM), for viewing earthquake focal mechanism symbols three dimensionally. This tool operates within the Environmental Systems Research Institute (ESRI®) GIS software ArcScene® 9.x. The program requires as input a GIS point dataset of earthquake locations containing strike, dip, and rake values for a nodal plane of each earthquake. Other information, such as depth and magnitude of the earthquake, may also be included in the dataset. By default for each focal point, 3DFM will create a black and white sphere or “beach ball” that is oriented based on the strike, dip, and rake values. If depth values for each earthquake are included, the focal symbol will also be placed at its appropriate location beneath the Earth's surface.

  18. Mechanisms of visual memory formation in bees: About immediate early genes and synaptic plasticity

    OpenAIRE

    Sommerlandt, Frank M. J.

    2016-01-01

    Animals form perceptual associations through processes of learning, and retain that information through mechanisms of memory. Honeybees and bumblebees are classic models for insect perception and learning, and despite their small brains with about one million neurons, they are organized in highly social colonies and possess an astonishing rich behavioral repertoire including navigation, communication and cognition. Honeybees are able to harvest hundreds of morphologically divergent flower typ...

  19. Visualizing the Mechanism of Epoxide Hydrolysis by the Bacterial Virulence Enzyme Cif.

    Science.gov (United States)

    Bahl, Christopher D; Hvorecny, Kelli L; Morisseau, Christophe; Gerber, Scott A; Madden, Dean R

    2016-02-09

    The CFTR inhibitory factor (Cif) is an epoxide hydrolase (EH) virulence factor secreted by the bacterium Pseudomonas aeruginosa. Sequence alignments reveal a pattern of Cif-like substitutions that proved to be characteristic of a new subfamily of bacterial EHs. At the same time, crystallographic and mutagenetic data suggest that EH activity is required for virulence and that Cif's active site remains generally compatible with a canonical two-step EH mechanism. A hallmark of this mechanism is the formation of a covalent hydroxyalkyl-enzyme intermediate by nucleophilic attack. In several well-studied EHs, this intermediate has been captured at near stoichiometric levels, presumably reflecting rate-limiting hydrolysis. Here we show by mass spectrometry that only minimal levels of the expected intermediate can be trapped with WT Cif. In contrast, substantial amounts of intermediate are recovered from an active-site mutant (Cif-E153Q) that selectively targets the second, hydrolytic release step. Utilizing Cif-E153Q and a previously reported nucleophile mutant (Cif-D129S), we then captured Cif in the substrate-bound, hydroxyalkyl-intermediate, and product-bound states for 1,2-epoxyhexane, yielding the first crystallographic snapshots of an EH at these key stages along the reaction coordinate. Taken together, our data illuminate the proposed two-step hydrolytic mechanism of a new class of bacterial virulence factor. They also suggest that the failure of WT Cif to accumulate a covalent hydroxyalkyl-enzyme intermediate reflects an active-site chemistry in which hydrolysis is no longer the rate-limiting step, a noncanonical kinetic regime that may explain similar observations with a number of other EHs.

  20. The advanced role of computational mechanics and visualization in science and technology: analysis of the Germanwings Flight 9525 crash

    Science.gov (United States)

    Chen, Goong; Wang, Yi-Ching; Perronnet, Alain; Gu, Cong; Yao, Pengfei; Bin-Mohsin, Bandar; Hajaiej, Hichem; Scully, Marlan O.

    2017-03-01

    Computational mathematics, physics and engineering form a major constituent of modern computational science, which now stands on an equal footing with the established branches of theoretical and experimental sciences. Computational mechanics solves problems in science and engineering based upon mathematical modeling and computing, bypassing the need for expensive and time-consuming laboratory setups and experimental measurements. Furthermore, it allows the numerical simulations of large scale systems, such as the formation of galaxies that could not be done in any earth bound laboratories. This article is written as part of the 21st Century Frontiers Series to illustrate some state-of-the-art computational science. We emphasize how to do numerical modeling and visualization in the study of a contemporary event, the pulverizing crash of the Germanwings Flight 9525 on March 24, 2015, as a showcase. Such numerical modeling and the ensuing simulation of aircraft crashes into land or mountain are complex tasks as they involve both theoretical study and supercomputing of a complex physical system. The most tragic type of crash involves ‘pulverization’ such as the one suffered by this Germanwings flight. Here, we show pulverizing airliner crashes by visualization through video animations from supercomputer applications of the numerical modeling tool LS-DYNA. A sound validation process is challenging but essential for any sophisticated calculations. We achieve this by validation against the experimental data from a crash test done in 1993 of an F4 Phantom II fighter jet into a wall. We have developed a method by hybridizing two primary methods: finite element analysis and smoothed particle hydrodynamics. This hybrid method also enhances visualization by showing a ‘debris cloud’. Based on our supercomputer simulations and the visualization, we point out that prior works on this topic based on ‘hollow interior’ modeling can be quite problematic and, thus, not

  1. Compressive deformation and yielding mechanisms in cellular Al alloys determined using X-ray tomography and surface strain mapping

    Energy Technology Data Exchange (ETDEWEB)

    Bart-Smith, H.; Bastawros, A.F.; Mumm, D.R.; Evans, A.G. [Harvard Univ., Cambridge, MA (United States). Div. of Engineering and Applied Sciences; Sypeck, D.J.; Wadley, H.N.G. [Univ. of Virginia, Charlottesville, VA (United States). School of Engineering and Applied Science

    1998-06-12

    The mechanisms of compressive deformation that occur in both closed and open cell Al alloys have been established. This has been achieved by using X-ray computed tomography (CT) and surface strain mapping to determine the deformation modes and the cell morphologies that control the onset of yielding. The deformation is found to localize in narrow bands having widths of order of a cell diameter. Outside the bands, the material remains elastic. The cells within the bands that experience large permanent strains are primarily elliptical. A group of cells work collectively to allow large localized deformation. Size does not appear to be the initiator of the deformation bands. Equiaxed cells remain elastic. The implications for manufacturing materials with superior mechanical properties are discussed.

  2. Using Maps to Promote Data-Driven Decision-Making: One Library's Experience in Data Visualization Instruction.

    Science.gov (United States)

    Catalano, Michelle Malizia; Vaughn, Porcia; Been, Joshua

    2017-01-01

    Data play a crucial role in health research, education, and patient care. Initiatives such as Big Data to Knowledge (BD2K) and Precision Medicine point to the increasing focus and value of data use and reuse. As the universe of data continues to grow exponentially, health education needs to provide students with practical hands-on learning sessions that illustrate the multitude of uses for data and statistics. Giving students early exposure to data reuse provides a solid background for the more complex data they may gather later in their education. This column describes how librarians at a general academic library used data dashboards and Tableau in two library sessions to provide students with hands-on experience in data visualization and its role in decision-making.

  3. Constructing visual representations

    DEFF Research Database (Denmark)

    Huron, Samuel; Jansen, Yvonne; Carpendale, Sheelagh

    2014-01-01

    The accessibility of infovis authoring tools to a wide audience has been identified as a major research challenge. A key task in the authoring process is the development of visual mappings. While the infovis community has long been deeply interested in finding effective visual mappings......, comparatively little attention has been placed on how people construct visual mappings. In this paper, we present the results of a study designed to shed light on how people transform data into visual representations. We asked people to create, update and explain their own information visualizations using only...... tangible building blocks. We learned that all participants, most of whom had little experience in visualization authoring, were readily able to create and talk about their own visualizations. Based on our observations, we discuss participants’ actions during the development of their visual representations...

  4. Visualizing the Crowd Web-based Participatory Practices as Innovative Tools in drawing and mapping Milano Città Metropolitana

    Directory of Open Access Journals (Sweden)

    Daniele Villa

    2014-05-01

    Full Text Available Many new questions arise with regard to Web3.0- based technologies, which are more and more frequently used by non-experts to generate and share geographic information, new collective urban visions and place-based knowledge. This paper discusses the role of participatory planning and mapping practices in the context of Milan metropolitan region. In particular taking into account the collaborative use of new technologies (such as the use of microblogging and geo-social networks within the processes of social sharing of the great urban transformations. Specific attention is given to the problems of perception and definition of shared landscape quality. In this context, the role of expert knowledge in the analysis and definition of the social perception of the urban landscape is now changing rapidly and radically.

  5. Recovery Action Mapping Tool

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Recovery Action Mapping Tool is a web map that allows users to visually interact with and query actions that were developed to recover species listed under the...

  6. Electrostatic frequency maps for amide-I mode of β-peptide: Comparison of molecular mechanics force field and DFT calculations

    Science.gov (United States)

    Cai, Kaicong; Zheng, Xuan; Du, Fenfen

    2017-08-01

    The spectroscopy of amide-I vibrations has been widely utilized for the understanding of dynamical structure of polypeptides. For the modeling of amide-I spectra, two frequency maps were built for β-peptide analogue (N-ethylpropionamide, NEPA) in a number of solvents within different schemes (molecular mechanics force field based, GM map; DFT calculation based, GD map), respectively. The electrostatic potentials on the amide unit that originated from solvents and peptide backbone were correlated to the amide-I frequency shift from gas phase to solution phase during map parameterization. GM map is easier to construct with negligible computational cost since the frequency calculations for the samples are purely based on force field, while GD map utilizes sophisticated DFT calculations on the representative solute-solvent clusters and brings insight into the electronic structures of solvated NEPA and its chemical environments. The results show that the maps' predicted amide-I frequencies present solvation environmental sensitivities and exhibit their specific characters with respect to the map protocols, and the obtained vibrational parameters are in satisfactory agreement with experimental amide-I spectra of NEPA in solution phase. Although different theoretical schemes based maps have their advantages and disadvantages, the present maps show their potentials in interpreting the amide-I spectra for β-peptides, respectively.

  7. Exploring particulate retention mechanisms through visualization of E. coli transport through a single, saturated fracture

    Science.gov (United States)

    Burke, M. G.; Dickson, S. E.; Schutten, M.

    2011-12-01

    Groundwater is an extremely valuable resource; a large body of work has been conducted towards remediating, tracking and reducing its contamination. Even so, there are large gaps within the current understanding of groundwater flow and contaminant transport, particularly within fractured media. Fractured media has the ability transport contaminants over longer distances in less time relative to porous media. Furthermore, colloids display unique transport characteristics in comparison to dissolved constituents, including the fact that they typically exhibit earlier initial arrival times. Of particular concern to human health are pathogenic microorganisms, which often originate from fecal contamination. Escherichia coli is a common indicator for fecal contamination; some strains are pathogenic, causing acute illness and sometimes death, in humans. A comprehensive understanding of the transport and retention of E. coli in fractured media will improve our ability to accurately assess whether a site is at risk of becoming contaminated by pathogenic microorganisms. Therefore, the goal of this work is to expand our mechanistic understanding particulate retention, specifically E. coli, in fractures, and the influence of flow rate on these mechanisms. In order to achieve this goal, clear epoxy casts were fabricated of two dolomitic limestone fractures retrieved from a quarry in Guelph, Ontario. Each aperture field was characterized through hydraulic and tracer tests, and measured directly using the light transmission technique. E. coli RS2-GFP, which is a non-pathogenic strain of E. coli that has been tagged with a green fluorescent protein, was injected into the cast under three separate specific discharges ranging from 5 - 30 m/d. These experiments were conducted on an ultraviolet light source, and a high resolution charged-couple device (CCD) camera was employed to take photos at regular intervals in order to capture the dominant flow paths and the areas of retention

  8. Diagnosis of regional cerebral blood flow abnormalities using SPECT: agreement between individualized statistical parametric maps and visual inspection by nuclear medicine physicians with different levels of expertise in nuclear neurology

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Euclides Timoteo da, E-mail: euclidestimoteo@uol.com.b [Fundacao Pio XII, Barretos, SP (Brazil). Hospital de Cancer. Dept. de Medicina Nuclear; Buchpiguel, Carlos Alberto [Hospital do Coracao, Sao Paulo, SP (Brazil). Dept. de Medicina Nuclear; Nitrini, Ricardo [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Dept. de Neurologia; Tazima, Sergio [Hospital Alemao Oswaldo Cruz (HAOC), Sao Paulo, SP (Brazil). Dept. de Medicina Nuclear; Peres, Stela Verzinhase [Fundacao Pio XII, Barretos, SP (Brazil). Hospital de Cancer; Busatto Filho, Geraldo [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Medicina. Div. de Medicina Nuclear

    2009-07-01

    Introduction: visual analysis is widely used to interpret regional cerebral blood flow (rCBF) SPECT images in clinical practice despite its limitations. Automated methods are employed to investigate between-group rCBF differences in research studies but have rarely been explored in individual analyses. Objectives: to compare visual inspection by nuclear physicians with the automated statistical parametric mapping program using a SPECT dataset of patients with neurological disorders and normal control images. Methods: using statistical parametric mapping, 14 SPECT images from patients with various neurological disorders were compared individually with a databank of 32 normal images using a statistical threshold of p<0.05 (corrected for multiple comparisons at the level of individual voxels or clusters). Statistical parametric mapping results were compared with visual analyses by a nuclear physician highly experienced in neurology (A) as well as a nuclear physician with a general background of experience (B) who independently classified images as normal or altered, and determined the location of changes and the severity. Results: of the 32 images of the normal databank, 4 generated maps showing rCBF abnormalities (p<0.05, corrected). Among the 14 images from patients with neurological disorders, 13 showed rCBF alterations. Statistical parametric mapping and physician A completely agreed on 84.37% and 64.28% of cases from the normal databank and neurological disorders, respectively. The agreement between statistical parametric mapping and ratings of physician B were lower (71.18% and 35.71%, respectively). Conclusion: statistical parametric mapping replicated the findings described by the more experienced nuclear physician. This finding suggests that automated methods for individually analyzing rCBF SPECT images may be a valuable resource to complement visual inspection in clinical practice. (author)

  9. Visualizing the spatiotemporal map of Rac activation in bovine aortic endothelial cells under laminar and disturbed flows

    National Research Council Canada - National Science Library

    Shuai Shao; Cheng Xiang; Kairong Qin; Aziz Ur Rehman Aziz; Xiaoling Liao; Bo Liu

    ..., and the mechanism of flow-induced cell polarity still needs to be elucidated. In this paper, disturbed flow or laminar flow with 15 dyn/cm2 of average shear stress was applied on bovine aortic endothelial cells (BAECs) for 30 minutes...

  10. Visualization and quantification of deformation processes controlling the mechanical response of alloys in aggressive environments

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Ian M. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering; Univ. of Illinois, Champaign, IL (United States)

    2017-01-05

    The overall objective of this program was to develop the technique of electron tomography for studies of defects and to couple it with real time dynamic experiments such that four-dimensional (time and three spatial dimensions) characterization of dislocation interactions with defects is feasible and apply it to discovery of the fundamental unit processes of dislocation-defect interactions in metallic systems. Strategies to overcome the restrictions normally associated with electron tomography and to make it practical within the constraints of conducting a dynamic experiment in the transmission electron microscope were developed. These methods were used to determine the mechanism controlling the transfer of slip across grain boundaries in FCC and HCP metals, dislocation precipitate interactions in Al alloys, and dislocation-dislocation interactions in HCP Ti. In addition, preliminary investigations of slip transfer across cube-on-cube and incoherent twin interfaces in a multi-layered system, thermal stability of grains in nanongrained Ni and Fe, and on corrosion of Fe films were conducted.

  11. Mapping of strain mechanisms in barium titanate by three-dimensional X-ray diffraction

    DEFF Research Database (Denmark)

    Majkut, Marta

    This thesis presents an in-situ three-dimensional study of the grain-scale response of a prototypical piezoelectric ceramic, barium titanate (BT), to an exernally applied electric field. Piezoceramics take advantage of the coupling of electrical and mechanical energies for use in sensors and actu......This thesis presents an in-situ three-dimensional study of the grain-scale response of a prototypical piezoelectric ceramic, barium titanate (BT), to an exernally applied electric field. Piezoceramics take advantage of the coupling of electrical and mechanical energies for use in sensors...

  12. Mechanisms underpinning successful decision making in skilled youth soccer players: an analysis of visual search behaviors.

    Science.gov (United States)

    Vaeyens, Roel; Lenoir, Matthieu; Williams, A Mark; Philippaerts, Renaat M

    2007-09-01

    The authors examined the complex interactions between perception, cognition, and expertise by using a film-based decision-making test. They stratified 40 youth soccer players (aged 13.0-15.8 years) into groups by using a within-task criterion. They assigned the players to successful or less successful groups on the basis of their performance on a laboratory-based test of tactical skill. Using soccer-specific film simulations, movement-based response measures, and eye movement registration techniques, the authors determined the players' decision-making processes and skill level. The results showed that investigators can use film-based tests to discriminate soccer players of comparable experience and playing level on the basis of their decision-making skills. When compared with their less successful counterparts, successful decision-makers used more goal-oriented search strategies, which resulted in superior performance, as characterized by faster decision times and greater response accuracy. Successful decision-makers (a) spent more time fixating the player in possession of the ball and (b) alternated gaze more frequently between that player and other areas of the display. An earlier study in which researchers (R. Vaeyens, M. Lenoir, A. M. Williams, L. Mazyn, & R. M. Philippaerts, 2007) stratified participants into groups on the basis of playing level had not revealed those differences. The implication of the present findings is that a within-task criterion provides investigators with a more sensitive approach when they try to identify the mechanisms underlying decision-making skill. Implications for research and practice are discussed.

  13. Perceptual learning of Gabor orientation identification in visual periphery: complete inter-ocular transfer of learning mechanisms.

    Science.gov (United States)

    Lu, Zhong-Lin; Chu, Wilson; Dosher, Barbara Anne; Lee, Sophia

    2005-09-01

    We combined the external noise paradigm, the Perceptual Template Model approach, and transfer tests to investigate the mechanisms and eye-specificity of perceptual learning of Gabor orientation in visual periphery. Coupled with a fixation task, discriminating a 5 from an S in a rapid small character string at fixation, contrast thresholds were estimated for each of eight external noise levels at two performance criteria using 3/1 and 2/1 staircases. Perceptual learning in one eye was measured over 10 practice sessions, followed by five sessions of practice in the new eye to assess transfer. We found that monocular learning improved performance (reduced contrast thresholds) with virtually equal magnitude across a wide range of external noise levels with no significant change in central task performance. Based on measurements of learning effects at two performance criterion levels, we identified a mixture of stimulus enhancement and external noise exclusion as the mechanism of perceptual learning underlying the observed improvements. Perceptual learning in the trained eye generalized completely to the untrained eye. We related the transfer patterns to known physiology and psychophysics on orientation direction coding.

  14. Four-dimensional visualization of subpleural alveolar dynamics in vivo during uninterrupted mechanical ventilation of living swine.

    Science.gov (United States)

    Namati, Eman; Warger, William C; Unglert, Carolin I; Eckert, Jocelyn E; Hostens, Jeroen; Bouma, Brett E; Tearney, Guillermo J

    2013-01-01

    Pulmonary alveoli have been studied for many years, yet no unifying hypothesis exists for their dynamic mechanics during respiration due to their miniature size (100-300 μm dimater in humans) and constant motion, which prevent standard imaging techniques from visualizing four-dimensional dynamics of individual alveoli in vivo. Here we report a new platform to image the first layer of air-filled subpleural alveoli through the use of a lightweight optical frequency domain imaging (OFDI) probe that can be placed upon the pleura to move with the lung over the complete range of respiratory motion. This device enables in-vivo acquisition of four-dimensional microscopic images of alveolar airspaces (alveoli and ducts), within the same field of view, during continuous ventilation without restricting the motion or modifying the structure of the alveoli. Results from an exploratory study including three live swine suggest that subpleural alveolar air spaces are best fit with a uniform expansion (r (2) = 0.98) over a recruitment model (r (2) = 0.72). Simultaneously, however, the percentage change in volume shows heterogeneous alveolar expansion within just a 1 mm x 1 mm field of view. These results signify the importance of four-dimensional imaging tools, such as the device presented here. Quantification of the dynamic response of the lung during ventilation may help create more accurate modeling techniques and move toward a more complete understanding of alveolar mechanics.

  15. Live fate-mapping of joint-associated fibroblasts visualizes expansion of cell contributions during zebrafish fin regeneration.

    Science.gov (United States)

    Tornini, Valerie A; Thompson, John D; Allen, Raymond L; Poss, Kenneth D

    2017-08-15

    The blastema is a mass of progenitor cells responsible for regeneration of amputated salamander limbs and fish fins. Previous studies have indicated that resident cell sources producing the blastema contribute lineage-restricted progeny to regenerating tissue. However, these studies have labeled general cell types rather than granular cell subpopulations, and they do not explain the developmental transitions that must occur for distal structures to arise from cells with proximal identities in the appendage stump. Here, we find that regulatory sequences of tph1b, which encodes an enzyme that synthesizes serotonin, mark a subpopulation of fibroblast-like cells restricted to the joints of uninjured adult zebrafish fins. Amputation stimulates serotonin production in regenerating fin fibroblasts, yet targeted tph1b mutations abrogating this response do not disrupt fin regeneration. In uninjured animals, tph1b-expressing cells contribute fibroblast progeny that remain restricted to joints throughout life. By contrast, upon amputation, tph1b+ joint cells give rise to fibroblasts that distribute across the entire lengths of regenerating fin rays. Our experiments visualize and quantify how incorporation into an appendage blastema broadens the progeny contributions of a cellular subpopulation that normally has proximodistal restrictions. © 2017. Published by The Company of Biologists Ltd.

  16. Expanding Thurston maps

    CERN Document Server

    Bonk, Mario

    2017-01-01

    This monograph is devoted to the study of the dynamics of expanding Thurston maps under iteration. A Thurston map is a branched covering map on a two-dimensional topological sphere such that each critical point of the map has a finite orbit under iteration. It is called expanding if, roughly speaking, preimages of a fine open cover of the underlying sphere under iterates of the map become finer and finer as the order of the iterate increases. Every expanding Thurston map gives rise to a fractal space, called its visual sphere. Many dynamical properties of the map are encoded in the geometry of this visual sphere. For example, an expanding Thurston map is topologically conjugate to a rational map if and only if its visual sphere is quasisymmetrically equivalent to the Riemann sphere. This relation between dynamics and fractal geometry is the main focus for the investigations in this work.

  17. Scanning probe acceleration microscopy (SPAM) in fluids: mapping mechanical properties of surfaces at the nanoscale.

    Science.gov (United States)

    Legleiter, Justin; Park, Matthew; Cusick, Brian; Kowalewski, Tomasz

    2006-03-28

    One of the major thrusts in proximal probe techniques is combination of imaging capabilities with simultaneous measurements of physical properties. In tapping mode atomic force microscopy (TMAFM), the most straightforward way to accomplish this goal is to reconstruct the time-resolved force interaction between the tip and surface. These tip-sample forces can be used to detect interactions (e.g., binding sites) and map material properties with nanoscale spatial resolution. Here, we describe a previously unreported approach, which we refer to as scanning probe acceleration microscopy (SPAM), in which the TMAFM cantilever acts as an accelerometer to extract tip-sample forces during imaging. This method utilizes the second derivative of the deflection signal to recover the tip acceleration trajectory. The challenge in such an approach is that with real, noisy data, the second derivative of the signal is strongly dominated by the noise. This problem is solved by taking advantage of the fact that most of the information about the deflection trajectory is contained in the higher harmonics, making it possible to filter the signal by "comb" filtering, i.e., by taking its Fourier transform and inverting it while selectively retaining only the intensities at integer harmonic frequencies. Such a comb filtering method works particularly well in fluid TMAFM because of the highly distorted character of the deflection signal. Numerical simulations and in situ TMAFM experiments on supported lipid bilayer patches on mica are reported to demonstrate the validity of this approach.

  18. p38 MAP kinase inhibition promotes primary tumour growth via VEGF independent mechanism.

    Science.gov (United States)

    O'Sullivan, Adrian W; Wang, Jiang H; Redmond, Henry P

    2009-11-15

    The surgical insult induces an inflammatory response that activates P38 MAP kinases and solid tumours can also release cytokines. Therfore inhibition of these pathways may reduce tumour growth We set out to examine the effects of P38-MAPK inhibition on apoptosis, proliferation, VEGF release and cell cycle effects in-vitro and on primary tumour growth in-vivo. 4T-1 cells (2 x 105 cells/well) were incubated, in 24 well plates with control, 25, 50 or 100 ng/ml of SB-202190 for 24 hours. Cells were subsequently asessed for apoptosis, proliferation, VEGF release and cell cycle analysis. Balb-c mice each received 1 x 106 4T 1 cells subcutaneously in the flank and were then randomised to receive control or SB202190 (2.5 microM/kg) by intraperitoneal injection daily. Tumour size was measured alternate days and at day 24 animals were sacrificed and serum VEGF assessed. P38-MAPK inhibition in-vitro resulted in a significant reduction in proliferation (75.2 +/- 8.4% vs. 100 +/- 4.3%, p etag/ml compared to 158.6 +/- 27.1 etag/ml) These findings demonstrate that P38-MAPK inhibition in-vitro reduces proliferation and G1 cell cycle phase as well as promoting primary tumour growth in-vivo. These effects would appear to be independent of VEGF.

  19. Topography and Mechanical Property Mapping of International Simple Glass Surfaces with Atomic Force Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, Eric M [ORNL

    2014-01-01

    Quantitative Nanomechanical Peak Force (PF-QNM) TappingModeTM atomic force microscopy measurements are presented for the first time on polished glass surfaces. The PF-QNM technique allows for topography and mechanical property information to be measured simultaneously at each pixel. Results for the international simple glass which represents a simplified version of SON68 glass suggests an average Young s modulus of 78.8 15.1 GPa is within the experimental error of the modulus measured for SON68 glass (83.6 2 GPa) with conventional approaches. Application of the PF-QNM technique will be extended to in situ glass corrosion experiments with the goal of gaining atomic-scale insights into altered layer development by exploiting the mechanical property differences that exist between silica gel (e.g., altered layer) and pristine glass surface.

  20. Mapping the Indicators. An Analysis of Sustainable Development Requirements of Selected Market Mechanisms and Multilateral Institutions

    DEFF Research Database (Denmark)

    Arens, Christof; Mersmann, Florian; Beuermann, Christiane

    in achieving sustainable development based on their national development priorities and strategies. However, complying with the second objective turned out to be problematic. Registered projects appeared that had no proven sustainable development benefits, or even perceived negative impacts. Consequently....... A robust assessment of the impact of sustainable development in CDM projects is important to ensure the social and ecological integrity of the mechanism and compliance with the objectives of sustainable development as stated in the Kyoto Protocol. Research and best practice experience into how sustainable...... development issues are integrated into mitigation actions through the CDM Sustainable Development Tool and other respective standards can help inform the development of Nationally Appropriate Mitigation Actions and future mechanisms on sustainable development assessment methods. As sustainable development...

  1. Security Mechanisms and Security-Aware Mapping for Real-Time Distributed Embedded Systems

    OpenAIRE

    Lin, Chung-Wei

    2015-01-01

    Cyber-security attacks can have a critical impact on embedded systems. They may access secret information, cause system malfunction, or even endanger users in extreme circumstances. These attacks become even more threatening as systems are becoming more connected with the surrounding environment, infrastructures, and other systems. These connections provide breeding grounds for attackers to get access to or take control of the systems. Security mechanisms can be designed to protect against at...

  2. Micro-abrasion resistance of thermochemically treated steels in aqueous solutions : mechanisms, maps, materials selection

    OpenAIRE

    Mathew, M. T.; Stack, M. M.; Matijevic, B.; Rocha, L. A.; Ariza, E.

    2008-01-01

    The area of micro-abrasion is an interesting and relatively recent area in tribo-testing methodologies, where small particles of less than 10 mm are employed between interacting surfaces. It is topical for a number of reasons; its direct relation to the mechanisms of the wear process in bio-tribological applications, ease in conducting tests and the good repeatability of the test results. It has widespread applications in conditions used in the space and offshore industries to bio-en...

  3. Novel mechanisms of sildenafil in pulmonary hypertension involving cytokines/chemokines, MAP kinases and Akt.

    Directory of Open Access Journals (Sweden)

    Tamas Kiss

    Full Text Available Pulmonary arterial hypertension (PH is associated with high mortality due to right ventricular failure and hypoxia, therefore to understand the mechanism by which pulmonary vascular remodeling initiates these processes is very important. We used a well-characterized monocrotaline (MCT-induced rat PH model, and analyzed lung morphology, expression of cytokines, mitogen-activated protein kinase (MAPK phosphorylation, and phosphatidylinositol 3-kinase-Akt (PI-3k-Akt pathway and nuclear factor (NF-κB activation in order to elucidate the mechanisms by which sildenafil's protective effect in PH is exerted. Besides its protective effect on lung morphology, sildenafil suppressed multiple cytokines involved in neutrophil and mononuclear cells recruitment including cytokine-induced neutrophil chemoattractant (CINC-1, CINC-2α/β, tissue inhibitor of metalloproteinase (TIMP-1, interleukin (IL-1α, lipopolysaccharide induced CXC chemokine (LIX, monokine induced by gamma interferon (MIG, macrophage inflammatory protein (MIP-1α, and MIP-3α. NF-κB activation and phosphorylation were also attenuated by sildenafil. Furthermore, sildenafil reduced extracellular signal-regulated kinase (ERK1/2 and p38 MAPK activation while enhanced activation of the cytoprotective Akt pathway in PH. These data suggest a beneficial effect of sildenafil on inflammatory and kinase signaling mechanisms that substantially contribute to its protective effects, and may have potential implications in designing future therapeutic strategies in the treatment of pulmonary hypertension.

  4. The dynamic process of cognitive mapping in the absence of visual cues: human data compared with animal studies.

    Science.gov (United States)

    Yaski, Osnat; Portugali, Juval; Eilam, David

    2009-08-01

    The present study aimed to investigate the behavior involved in constructing spatial representation in humans. For this, blindfolded adult human subjects were introduced into an unfamiliar environment, where they were requested to move incessantly for 10 min. Analysis of the locomotor activity of the participants revealed the following exploratory behaviors: (1) ;looping'; (2) ;wall-following'; (3) ;step-counting'; (4) ;cross-cutting'; and (5) ;free traveling'. Looping is a typical exploratory mode of sightless explorers, based on returning to a recently traveled place. Wall-following is common in enclosed spaces, whereby explorers follow the perimeter of the environment. Both looping and wall-following are based on an egocentric frame of reference by which explorers obtain information about the shape, size and landmarks in the environment. Blindfolded explorers displayed step-counting in order to scale the environment and the relationships in it. Altogether, exploration by looping, wall-following and step-counting resulted in an allocentric spatial representation. The acquisition of spatial representation was manifested by cross-cutting and free travel, with subjects walking in a relatively fast and decisive manner. In light of the above modes of activity, we suggest that exploration of an unfamiliar environment is a synergetic self-organized process (synergetic inter-representation networks, SIRN model); an interplay between external and internal representations. According to this model, the interplay gives rise to an order parameter, such as the environment's dimensions or geometry, enabling progression to a subsequent exploratory behavior. This dynamic and sequential interplay reaches a steady state when a spatial representation (i.e. ;cognitive map') is established.

  5. A RAD-tag genetic map for the platyfish (Xiphophorus maculatus) reveals mechanisms of karyotype evolution among teleost fish.

    Science.gov (United States)

    Amores, Angel; Catchen, Julian; Nanda, Indrajit; Warren, Wesley; Walter, Ron; Schartl, Manfred; Postlethwait, John H

    2014-06-01

    Mammalian genomes can vary substantially in haploid chromosome number even within a small taxon (e.g., 3-40 among deer alone); in contrast, teleost fish genomes are stable (24-25 in 58% of teleosts), but we do not yet understand the mechanisms that account for differences in karyotype stability. Among perciform teleosts, platyfish (Xiphophorus maculatus) and medaka (Oryzias latipes) both have 24 chromosome pairs, but threespine stickleback (Gasterosteus aculeatus) and green pufferfish (Tetraodon nigroviridis) have just 21 pairs. To understand the evolution of teleost genomes, we made a platyfish meiotic map containing 16,114 mapped markers scored on 267 backcross fish. We tiled genomic contigs along the map to create chromosome-length genome assemblies. Genome-wide comparisons of conserved synteny showed that platyfish and medaka karyotypes remained remarkably similar with few interchromosomal translocations but with numerous intrachromosomal rearrangements (transpositions and inversions) since their lineages diverged ∼120 million years ago. Comparative genomics with platyfish shows how reduced chromosome numbers in stickleback and green pufferfish arose by fusion of pairs of ancestral chromosomes after their lineages diverged from platyfish ∼195 million years ago. Zebrafish and human genomes provide outgroups to root observed changes. These studies identify likely genome assembly errors, characterize chromosome fusion events, distinguish lineage-independent chromosome fusions, show that the teleost genome duplication does not appear to have accelerated the rate of translocations, and reveal the stability of syntenies and gene orders in teleost chromosomes over hundreds of millions of years. Copyright © 2014 by the Genetics Society of America.

  6. Toward a better understanding of the mechanisms of symbiosis: a comprehensive proteome map of a nascent insect symbiont

    Directory of Open Access Journals (Sweden)

    François Renoz

    2017-05-01

    Full Text Available Symbiotic bacteria are common in insects and can affect various aspects of their hosts’ biology. Although the effects of insect symbionts have been clarified for various insect symbiosis models, due to the difficulty of cultivating them in vitro, there is still limited knowledge available on the molecular features that drive symbiosis. Serratia symbiotica is one of the most common symbionts found in aphids. The recent findings of free-living strains that are considered as nascent partners of aphids provide the opportunity to examine the molecular mechanisms that a symbiont can deploy at the early stages of the symbiosis (i.e., symbiotic factors. In this work, a proteomic approach was used to establish a comprehensive proteome map of the free-living S. symbiotica strain CWBI-2.3T. Most of the 720 proteins identified are related to housekeeping or primary metabolism. Of these, 76 were identified as candidate proteins possibly promoting host colonization. Our results provide strong evidence that S. symbiotica CWBI-2.3T is well-armed for invading insect host tissues, and suggest that certain molecular features usually harbored by pathogenic bacteria are no longer present. This comprehensive proteome map provides a series of candidate genes for further studies to understand the molecular cross-talk between insects and symbiotic bacteria.

  7. Genome-wide maps of alkylation damage, repair, and mutagenesis in yeast reveal mechanisms of mutational heterogeneity.

    Science.gov (United States)

    Mao, Peng; Brown, Alexander J; Malc, Ewa P; Mieczkowski, Piotr A; Smerdon, Michael J; Roberts, Steven A; Wyrick, John J

    2017-10-01

    DNA base damage is an important contributor to genome instability, but how the formation and repair of these lesions is affected by the genomic landscape and contributes to mutagenesis is unknown. Here, we describe genome-wide maps of DNA base damage, repair, and mutagenesis at single nucleotide resolution in yeast treated with the alkylating agent methyl methanesulfonate (MMS). Analysis of these maps revealed that base excision repair (BER) of alkylation damage is significantly modulated by chromatin, with faster repair in nucleosome-depleted regions, and slower repair and higher mutation density within strongly positioned nucleosomes. Both the translational and rotational settings of lesions within nucleosomes significantly influence BER efficiency; moreover, this effect is asymmetric relative to the nucleosome dyad axis and is regulated by histone modifications. Our data also indicate that MMS-induced mutations at adenine nucleotides are significantly enriched on the nontranscribed strand (NTS) of yeast genes, particularly in BER-deficient strains, due to higher damage formation on the NTS and transcription-coupled repair of the transcribed strand (TS). These findings reveal the influence of chromatin on repair and mutagenesis of base lesions on a genome-wide scale and suggest a novel mechanism for transcription-associated mutation asymmetry, which is frequently observed in human cancers. © 2017 Mao et al.; Published by Cold Spring Harbor Laboratory Press.

  8. Perceptual Dependencies in Information Visualization Assessed by Complex Visual Search

    NARCIS (Netherlands)

    Berg, Ronald van den; Cornelissen, Frans W.; Roerdink, Jos B.T.M.

    A common approach for visualizing data sets is to map them to images in which distinct data dimensions are mapped to distinct visual features, such as color, size and orientation. Here, we consider visualizations in which different data dimensions should receive equal weight and attention. Many of

  9. Infrared (0.83–5.1 μm) photometry of Phoebe from the Cassini Visual Infrared Mapping Spectrometer

    Science.gov (United States)

    Buratti, B.J.; Soderlund, K.; Bauer, J.; Mosher, J.A.; Hicks, M.D.; Simonelli, D.P.; Jaumann, R.; Clark, R.N.; Brown, R.H.; Cruikshank, D.P.; Momary, T.

    2008-01-01

    Three weeks prior to the commencement of Cassini's   4 year tour of the saturnian system, the spacecraft executed a close flyby of the outer satellite Phoebe. The infrared channel of the Visual Infrared Mapping Spectrometer (VIMS) obtained images of reflected light over the 0.83–5.1 μm spectral range with an average spectral resolution of 16.5 nm, spatial resolution up to 2 km, and over a range of solar phase angles not observed before. These images have been analyzed to derive fundamental photometric parameters including the phase curve and phase integral, spectral geometric albedo, bolometric Bond albedo, and the single scattering albedo. Physical properties of the surface, including macroscopic roughness and the single particle phase function, have also been characterized. Maps of normal reflectance show the existence of two major albedo regimes in the infrared, with gradations between the two regimes and much terrain with substantially higher albedos. The phase integral of Phoebe is 0.29±0.030.29±0.03, with no significant wavelength dependence. The bolometric Bond albedo is 0.023±0070.023±007. We find that the surface of Phoebe is rough, with a mean slope angle of 33°. The satellite's surface has a substantial forward scattering component, suggesting that its surface is dusty, perhaps from a history of outgassing. The spectrum of Phoebe is best matched by a composition including water ice, amorphous carbon, iron-bearing minerals, carbon dioxide, and Triton tholin. The characteristics of Phoebe suggest that it originated outside the saturnian system, perhaps in the Kuiper Belt, and was captured on its journey inward, as suggested by Johnson and Lunine (2005).

  10. Insights into Photosystem II from Isomorphous Difference Fourier Maps of Femtosecond X-ray Diffraction Data and Quantum Mechanics/Molecular Mechanics Structural Models.

    Science.gov (United States)

    Wang, Jimin; Askerka, Mikhail; Brudvig, Gary W; Batista, Victor S

    2017-02-10

    Understanding structure-function relations in photosystem II (PSII) is important for the development of biomimetic photocatalytic systems. X-ray crystallography, computational modeling, and spectroscopy have played central roles in elucidating the structure and function of PSII. Recent breakthroughs in femtosecond X-ray crystallography offer the possibility of collecting diffraction data from the X-ray free electron laser (XFEL) before radiation damage of the sample, thereby overcoming the main challenge of conventional X-ray diffraction methods. However, the interpretation of XFEL data from PSII intermediates is challenging because of the issues regarding data-processing, uncertainty on the precise positions of light oxygen atoms next to heavy metal centers, and different kinetics of the S-state transition in microcrystals compared to solution. Here, we summarize recent advances and outstanding challenges in PSII structure-function determination with emphasis on the implementation of quantum mechanics/molecular mechanics techniques combined with isomorphous difference Fourier maps, direct methods, and high-resolution spectroscopy.

  11. Mapping the mechanical heterogeneity of the brain, and why this matters (Conference Presentation)

    Science.gov (United States)

    Guck, Jochen R.

    2017-02-01

    It is increasingly recognized that cells measure and respond to the mechanics of their environment. We are especially interested in this mechanosensing during CNS development and pathologies. Using quantitative scanning force microscopy we have shown that various neural tissues are very compliant (shear modulus root of foreign body reactions. Also oligodendrocytes are mechanosensitive as their survival, proliferation, migration, and differentiation capacity in vitro depend on substrate stiffness. This finding might be linked to the failure of remyelination in chronic demyelinating diseases such as multiple sclerosis. And finally, we have also shown retinal ganglion axon pathfinding in the early embryonic Xenopus brain development to be instructed by stiffness gradients. These results form the basis for further investigations into the mechanobiology of cell function in the CNS. Ultimately, this research could help treating previously incurable neuropathologies such as spinal cord injuries and neurodegenerative disorders.

  12. The mechanism of MAP kinase activation under acidic condition in feline esophageal smooth muscle cells.

    Science.gov (United States)

    Park, Sun Young; Lee, Young Ju; Min, Youngsil; Kim, Hak Rim; Jeong, Ji Hoon; Sohn, Uy Dong

    2011-10-01

    Reflux esophagitis results from repeated exposure of the esophagus to acidic gastric juice or bile-containing duodenal contents. In Barrett's adenocarcinoma, acid increases proliferation via ERK and p38 MAPK activation. This study was focused on determination of the mechanism(s) underlying MAPKs (ERK 1/2, p38 MAPK, and JNK) activation induced by acidic medium at pH 4 in normal feline primary cultured esophageal smooth muscle cells (FESMCs). We detected ERK 1/2 and p38 MAPK phosphorylation after exposure to pH 4 or neutral media in the presence or absence of several inhibitors and quantified the MAPK levels using western blotting analysis and densitometry. Acidic medium markedly increased the phosphorylation of ERK 1/2 and p38 MAPK within 10 min. Acid-induced ERK 1/2 and p38 MAPK activation was inhibited by pertussis toxin (PTX-sensitive G(i/o) protein inhibitor), DEDA (phospholipase (PL) A(2) inhibitor), ρCMB (PLD inhibitor), GF109203X (protein kinase C (PKC) inhibitor) and D609 (phosphatidylcholine-specific PLC inhibitor). But, genistein (tyrosine kinase inhibitor), forskolin (adenylate cyclase activator) and U73122 (phosphatidylinositol-specific PLC inhibitor) had no effect on acid-induced ERK1/2 and p38 MAPK activation. These findings indicate that the activation of ERK 1/2 and p38 MAPK pathways by acidic conditions, at least in part, may be mediated by activation of the G(i/o) protein coupled receptors, PC-PLC, PLD, PLA(2), and PKC in FESMCs.

  13. Monitoring of Structures and Mechanical Systems Using Virtual Visual Sensors for Video Analysis: Fundamental Concept and Proof of Feasibility

    Directory of Open Access Journals (Sweden)

    Thomas Schumacher

    2013-12-01

    Full Text Available Structural health monitoring (SHM has become a viable tool to provide owners of structures and mechanical systems with quantitative and objective data for maintenance and repair. Traditionally, discrete contact sensors such as strain gages or accelerometers have been used for SHM. However, distributed remote sensors could be advantageous since they don’t require cabling and can cover an area rather than a limited number of discrete points. Along this line we propose a novel monitoring methodology based on video analysis. By employing commercially available digital cameras combined with efficient signal processing methods we can measure and compute the fundamental frequency of vibration of structural systems. The basic concept is that small changes in the intensity value of a monitored pixel with fixed coordinates caused by the vibration of structures can be captured by employing techniques such as the Fast Fourier Transform (FFT. In this paper we introduce the basic concept and mathematical theory of this proposed so-called virtual visual sensor (VVS, we present a set of initial laboratory experiments to demonstrate the accuracy of this approach, and provide a practical in-service monitoring example of an in-service bridge. Finally, we discuss further work to improve the current methodology.

  14. Multinomial Logistic Regression Predicted Probability Map To Visualize The Influence Of Socio-Economic Factors On Breast Cancer Occurrence in Southern Karnataka

    Science.gov (United States)

    Madhu, B.; Ashok, N. C.; Balasubramanian, S.

    2014-11-01

    Multinomial logistic regression analysis was used to develop statistical model that can predict the probability of breast cancer in Southern Karnataka using the breast cancer occurrence data during 2007-2011. Independent socio-economic variables describing the breast cancer occurrence like age, education, occupation, parity, type of family, health insurance coverage, residential locality and socioeconomic status of each case was obtained. The models were developed as follows: i) Spatial visualization of the Urban- rural distribution of breast cancer cases that were obtained from the Bharat Hospital and Institute of Oncology. ii) Socio-economic risk factors describing the breast cancer occurrences were complied for each case. These data were then analysed using multinomial logistic regression analysis in a SPSS statistical software and relations between the occurrence of breast cancer across the socio-economic status and the influence of other socio-economic variables were evaluated and multinomial logistic regression models were constructed. iii) the model that best predicted the occurrence of breast cancer were identified. This multivariate logistic regression model has been entered into a geographic information system and maps showing the predicted probability of breast cancer occurrence in Southern Karnataka was created. This study demonstrates that Multinomial logistic regression is a valuable tool for developing models that predict the probability of breast cancer Occurrence in Southern Karnataka.

  15. Epitope mapping for monoclonal antibody reveals the activation mechanism for αVβ3 integrin.

    Directory of Open Access Journals (Sweden)

    Tetsuji Kamata

    Full Text Available Epitopes for a panel of anti-αVβ3 monoclonal antibodies (mAbs were investigated to explore the activation mechanism of αVβ3 integrin. Experiments utilizing αV/αIIb domain-swapping chimeras revealed that among the nine mAbs tested, five recognized the ligand-binding β-propeller domain and four recognized the thigh domain, which is the upper leg of the αV chain. Interestingly, the four mAbs included function-blocking as well as non-functional mAbs, although they bound at a distance from the ligand-binding site. The epitopes for these four mAbs were further determined using human-to-mouse αV chimeras. Among the four, P3G8 recognized an amino acid residue, Ser-528, located on the side of the thigh domain, while AMF-7, M9, and P2W7 all recognized a common epitope, Ser-462, that was located close to the α-genu, where integrin makes a sharp bend in the crystal structure. Fibrinogen binding studies for cells expressing wild-type αVβ3 confirmed that AMF-7, M9, and P2W7 were inhibitory, while P3G8 was non-functional. However, these mAbs were all unable to block binding when αVβ3 was constrained in its extended conformation. These results suggest that AMF-7, M9, and P2W7 block ligand binding allosterically by stabilizing the angle of the bend in the bent conformation. Thus, a switchblade-like movement of the integrin leg is indispensable for the affinity regulation of αVβ3 integrin.

  16. Mechanical characterization of sawn timber for structural use, graded visually in accordance with Spanish standard UNE 56544

    Directory of Open Access Journals (Sweden)

    Fernández-Golfín, J. I.

    1998-12-01

    Full Text Available The employment of timber in structures in Spain was hurting of the nonexistence of accepted calculation procedures. The recent adoption and publication of the Eurocode 5 compels to the employment of the characteristic values of the material in the structural calculation by the method of the finite elements. This report sets forth the results of the experiments carried out at INIA's Forest Research Centre (CIFOR-INIA regarding the mechanical characterization of sawn timber of size 150x50x3.000 mm and the structural uses of "Pinus sylvestris, P. radiata and P. pinaster" from different Spanish provenances. The characteristic values and strength classes corresponding with the grades stated in the Spanish standard UNE 56544 are also provided. The report compares and analyses the results of these experiments, and presents the conclusions drawn from the different behaviour shown by the four species. An analysis of the Spanish standard for the visual grading of structural timber is carried out on the three species.

    El empleo de la madera en la construcción en España adolecía de la inexistencia de procedimientos de cálculo normalizados. La reciente adopción y publicación del Eurocódigo 5 obliga al empleo de los valores característicos del material en el cálculo estructural de la madera por el método de los elementos finitos. Se presentan los resultados de la caracterización mecánica de la madera aserrada de tamaño (150x50x3.000 mm y usos estructurales de "Pinus sylvestris, P. radiata y P. pinaster" de diferentes procedencias, llevada a cabo en el Centro de Investigación Forestal (CIFOR del INIA. Se aportan los valores característicos y clases de resistencia que corresponden a las clases de calidad definidas en la norma UNE 56544. Se efectúa una comparación y análisis de los resultados obtenidos, extrayendo conclusiones respecto del diferente comportamiento observado para las cuatro especies. Se analiza la adecuación de la

  17. Processing of visual semantic information to concrete words : temporal dynamics and neural mechanisms indicated by event-related brain potentials

    NARCIS (Netherlands)

    van Schie, Hein T.; Wijers, Albertus A.; Mars, Rogier B.; Benjamins, Jeroen S.; Stowe, Laurie A.

    2005-01-01

    Event-related brain potentials were used to study the retrieval of visual semantic information to concrete words, and to investigate possible structural overlap between visual object working memory and concreteness effects in word processing. Subjects performed an object working memory task that

  18. Processing of visual semantic information to concrete words: temporal dynamics and neural mechanisms indicated by event-related brain potentials

    NARCIS (Netherlands)

    Schie, H.T. van; Wijers, A.A.; Mars, R.B.; Benjamins, J.S.; Stowe, L.A.

    2005-01-01

    Event-related brain potentials were used to study the retrieval of visual semantic information to concrete words, and to investigate possible structural overlap between visual object working memory and concreteness effects in word processing. Subjects performed an object working memory task that

  19. Visual cognition

    Energy Technology Data Exchange (ETDEWEB)

    Pinker, S.

    1985-01-01

    This collection of research papers on visual cognition first appeared as a special issue of Cognition: International Journal of Cognitive Science. The study of visual cognition has seen enormous progress in the past decade, bringing important advances in our understanding of shape perception, visual imagery, and mental maps. Many of these discoveries are the result of converging investigations in different areas, such as cognitive and perceptual psychology, artificial intelligence, and neuropsychology. This volume is intended to highlight a sample of work at the cutting edge of this research area for the benefit of students and researchers in a variety of disciplines. The tutorial introduction that begins the volume is designed to help the nonspecialist reader bridge the gap between the contemporary research reported here and earlier textbook introductions or literature reviews.

  20. Enridged Contour Maps

    NARCIS (Netherlands)

    Wijk, Jarke J. van; Telea, Alexandru

    2001-01-01

    The visualization of scalar functions of two variables is a classic and ubiquitous application. We present a new method to visualize such data. The method is based on a non-linear mapping of the function to a height field, followed by visualization as a shaded mountain landscape. The method is easy

  1. Conceptual size representation in ventral visual cortex.

    Science.gov (United States)

    Gabay, Shai; Kalanthroff, Eyal; Henik, Avishai; Gronau, Nurit

    2016-01-29

    Recent findings suggest that visual objects may be mapped along the ventral occipitotemporal cortex according to their real-world size (Konkle and Oliva, 2012). It has been argued that such mapping does not reflect an abstract, conceptual size representation, but rather the visual or functional properties associated with small versus big real-world objects. To determine whether a more abstract conceptual size representation may affect visual cortical activation we used meaningless geometrical shapes, devoid of semantic or functional associations, which were associated with specific size representations by virtue of extensive training. Following training, participants underwent functional magnetic resonance imaging (fMRI) scanning while performing a conceptual size comparison task on the geometrical shapes. In addition, a size comparison task was conducted for numeral digits denoting small and big numbers. A region-of-interest analysis revealed larger blood oxygenation level dependent (BOLD) responses for conceptually 'big' than for conceptually 'small' shapes, as well as for big versus small numbers, within medial (parahippocampal place area, PPA) and lateral (occipital place area, OPA) place-selective regions. Processing of the 'big' visual shapes further elicited enhanced activation in early visual cortex, possibly reflecting top-down projections from PPA. By using arbitrary shapes and numbers we minimized visual, categorical, or functional influences on fMRI measurement, providing evidence for a possible neural mechanism underlying the representation of abstract conceptual size within the ventral visual stream. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Mapping, Learning, Visualization, Classification, and Understanding of fMRI Data in the NeuCube Evolving Spatiotemporal Data Machine of Spiking Neural Networks.

    Science.gov (United States)

    Kasabov, Nikola K; Doborjeh, Maryam Gholami; Doborjeh, Zohreh Gholami

    2017-04-01

    This paper introduces a new methodology for dynamic learning, visualization, and classification of functional magnetic resonance imaging (fMRI) as spatiotemporal brain data. The method is based on an evolving spatiotemporal data machine of evolving spiking neural networks (SNNs) exemplified by the NeuCube architecture [1]. The method consists of several steps: mapping spatial coordinates of fMRI data into a 3-D SNN cube (SNNc) that represents a brain template; input data transformation into trains of spikes; deep, unsupervised learning in the 3-D SNNc of spatiotemporal patterns from data; supervised learning in an evolving SNN classifier; parameter optimization; and 3-D visualization and model interpretation. Two benchmark case study problems and data are used to illustrate the proposed methodology-fMRI data collected from subjects when reading affirmative or negative sentences and another one-on reading a sentence or seeing a picture. The learned connections in the SNNc represent dynamic spatiotemporal relationships derived from the fMRI data. They can reveal new information about the brain functions under different conditions. The proposed methodology allows for the first time to analyze dynamic functional and structural connectivity of a learned SNN model from fMRI data. This can be used for a better understanding of brain activities and also for online generation of appropriate neurofeedback to subjects for improved brain functions. For example, in this paper, tracing the 3-D SNN model connectivity enabled us for the first time to capture prominent brain functional pathways evoked in language comprehension. We found stronger spatiotemporal interaction between left dorsolateral prefrontal cortex and left temporal while reading a negated sentence. This observation is obviously distinguishable from the patterns generated by either reading affirmative sentences or seeing pictures. The proposed NeuCube-based methodology offers also a superior classification accuracy

  3. Mapping landscape corridors

    Science.gov (United States)

    Peter Vogt; Kurt H. Riitters; Marcin Iwanowski; Christine Estreguil; Jacek Kozak; Pierre Soille

    2007-01-01

    Corridors are important geographic features for biological conservation and biodiversity assessment. The identification and mapping of corridors is usually based on visual interpretations of movement patterns (functional corridors) or habitat maps (structural corridors). We present a method for automated corridor mapping with morphological image processing, and...

  4. Declarative Visualization Queries

    Science.gov (United States)

    Pinheiro da Silva, P.; Del Rio, N.; Leptoukh, G. G.

    2011-12-01

    In an ideal interaction with machines, scientists may prefer to write declarative queries saying "what" they want from a machine than to write code stating "how" the machine is going to address the user request. For example, in relational database, users have long relied on specifying queries using Structured Query Language (SQL), a declarative language to request data results from a database management system. In the context of visualizations, we see that users are still writing code based on complex visualization toolkit APIs. With the goal of improving the scientists' experience of using visualization technology, we have applied this query-answering pattern to a visualization setting, where scientists specify what visualizations they want generated using a declarative SQL-like notation. A knowledge enhanced management system ingests the query and knows the following: (1) know how to translate the query into visualization pipelines; and (2) how to execute the visualization pipelines to generate the requested visualization. We define visualization queries as declarative requests for visualizations specified in an SQL like language. Visualization queries specify what category of visualization to generate (e.g., volumes, contours, surfaces) as well as associated display attributes (e.g., color and opacity), without any regards for implementation, thus allowing scientists to remain partially unaware of a wide range of visualization toolkit (e.g., Generic Mapping Tools and Visualization Toolkit) specific implementation details. Implementation details are only a concern for our knowledge-based visualization management system, which uses both the information specified in the query and knowledge about visualization toolkit functions to construct visualization pipelines. Knowledge about the use of visualization toolkits includes what data formats the toolkit operates on, what formats they output, and what views they can generate. Visualization knowledge, which is not

  5. Geometrical and mechanical properties of the fractures and brittle deformation zones based on the ONKALO tunnel mapping, 2400 - 4390 m tunnel chainage

    Energy Technology Data Exchange (ETDEWEB)

    Moenkkoenen, H.; Rantanen, T.; Kuula, H. [WSP Finland Oy, Helsinki (Finland)

    2012-05-15

    In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO area at the Olkiluoto site, western Finland. This report is an extension of the previously published report: Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0-2400 m tunnel chainage (Kuula 2010). In this updated report, mapping data are from 2400-4390 m tunnel chainage. Defined rock mechanics parameters of the fractures are associated with the rock engineering classification quality index, Q', which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. There are no new data from laboratory joint shear and normal tests. The fracture wall compressive strength (JCS) data are available from the chainage range 1280-2400 m. Estimation of the mechanics properties of the 24 brittle deformation zones (BDZ) is based on the mapped Q' value, which is transformed to the GSI value in order to estimate strength and deformability properties. A component of the mapped Q' values is from the ONKALO and another component is from the drill cores. In this study, 24 BDZs have been parameterized. The location and size of the brittle deformation are based on the latest interpretation. New data for intact rock strength of the brittle deformation zones are not available. (orig.)

  6. TAK1 (MAP3K7 signaling regulates hematopoietic stem cells through TNF-dependent and -independent mechanisms.

    Directory of Open Access Journals (Sweden)

    Giichi Takaesu

    Full Text Available A cytokine/stress signaling kinase Tak1 (Map3k7 deficiency is known to impair hematopoietic progenitor cells. However, the role of TAK1 signaling in the stem cell function of the hematopoietic system is not yet well defined. Here we characterized hematopoietic stem cells (HSCs harboring deletion of Tak1 and its activators, Tak1 binding proteins 1 and 2 (Tab1 and Tab2 using a competitive transplantation assay in a mouse model. Tak1 single or Tab1/Tab2 double deletions completely eliminated the reconstitution activity of HSCs, whereas Tab1 or Tab2 single deletion did not cause any abnormality. Tak1 single or Tab1/Tab2 double deficient lineage-negative, Sca-1(+, c-Kit(+ (LSK cells did not proliferate and underwent cell death. We found that Tnfr1 deficiency restored the reconstitution activity of Tak1 deficient bone marrow cells for 6-18 weeks. However, the reconstitution activity of Tak1- and Tnfr1-double deficient bone marrow cells declined over the long term, and the number of phenotypically identified long-term hematopoietic stem cells were diminished. Our results indicate that TAB1- or TAB2-dependent activation of TAK1 is required for maintenance of the hematopoietic system through two mechanisms: one is prevention of TNF-dependent cell death and the other is TNF-independent maintenance of long-term HSC.

  7. Genome Sequencing and Mapping Reveal Loss of Heterozygosity as a Mechanism for Rapid Adaptation in the Vegetable Pathogen Phytophthora capsici

    Energy Technology Data Exchange (ETDEWEB)

    Lamour, Kurt H.; Mudge, Joann; Gobena, Daniel; Hurtado-Gonzales, Oscar P.; Schmutz, Jeremy; Kuo, Alan; Miller, Neil A.; Rice, Brandon J.; Raffaele, Sylvain; Cano, Liliana M.; Bharti, Arvind K.; Donahoo, Ryan S.; Finely, Sabra; Huitema, Edgar; Hulvey, Jon; Platt, Darren; Salamov, Asaf; Savidor, Alon; Sharma, Rahul; Stam, Remco; Sotrey, Dylan; Thines, Marco; Win, Joe; Haas, Brian J.; Dinwiddie, Darrell L.; Jenkins, Jerry; Knight, James R.; Affourtit, Jason P.; Han, Cliff S.; Chertkov, Olga; Lindquist, Erika A.; Detter, Chris; Grigoriev, Igor V.; Kamoun, Sophien; Kingsmore, Stephen F.

    2012-02-07

    The oomycete vegetable pathogen Phytophthora capsici has shown remarkable adaptation to fungicides and new hosts. Like other members of this destructive genus, P. capsici has an explosive epidemiology, rapidly producing massive numbers of asexual spores on infected hosts. In addition, P. capsici can remain dormant for years as sexually recombined oospores, making it difficult to produce crops at infested sites, and allowing outcrossing populations to maintain significant genetic variation. Genome sequencing, development of a high-density genetic map, and integrative genomic or genetic characterization of P. capsici field isolates and intercross progeny revealed significant mitotic loss of heterozygosity (LOH) in diverse isolates. LOH was detected in clonally propagated field isolates and sexual progeny, cumulatively affecting >30percent of the genome. LOH altered genotypes for more than 11,000 single-nucleotide variant sites and showed a strong association with changes in mating type and pathogenicity. Overall, it appears that LOH may provide a rapid mechanism for fixing alleles and may be an important component of adaptability for P. capsici.

  8. Participatory maps

    DEFF Research Database (Denmark)

    Salovaara-Moring, Inka

    towards a new political ecology. This type of digital cartographies has been highlighted as the ‘processual turn’ in critical cartography, whereas in related computational journalism it can be seen as an interactive and iterative process of mapping complex and fragile ecological developments. This paper...... looks at computer-assisted cartography as part of environmental knowledge production. It uses InfoAmazonia, the databased platform on Amazon rainforests, as an example of affective geo-visualization within information mapping that enhances embodiment in the experience of the information. Amazonia...

  9. Visualizing water

    Science.gov (United States)

    Baart, F.; van Gils, A.; Hagenaars, G.; Donchyts, G.; Eisemann, E.; van Velzen, J. W.

    2016-12-01

    A compelling visualization is captivating, beautiful and narrative. Here we show how melding the skills of computer graphics, art, statistics, and environmental modeling can be used to generate innovative, attractive and very informative visualizations. We focus on the topic of visualizing forecasts and measurements of water (water level, waves, currents, density, and salinity). For the field of computer graphics and arts, water is an important topic because it occurs in many natural scenes. For environmental modeling and statistics, water is an important topic because the water is essential for transport, a healthy environment, fruitful agriculture, and a safe environment.The different disciplines take different approaches to visualizing water. In computer graphics, one focusses on creating water as realistic looking as possible. The focus on realistic perception (versus the focus on the physical balance pursued by environmental scientists) resulted in fascinating renderings, as seen in recent games and movies. Visualization techniques for statistical results have benefited from the advancement in design and journalism, resulting in enthralling infographics. The field of environmental modeling has absorbed advances in contemporary cartography as seen in the latest interactive data-driven maps. We systematically review the design emerging types of water visualizations. The examples that we analyze range from dynamically animated forecasts, interactive paintings, infographics, modern cartography to web-based photorealistic rendering. By characterizing the intended audience, the design choices, the scales (e.g. time, space), and the explorability we provide a set of guidelines and genres. The unique contributions of the different fields show how the innovations in the current state of the art of water visualization have benefited from inter-disciplinary collaborations.

  10. Visualizing guided tours

    DEFF Research Database (Denmark)

    Poulsen, Signe Herbers; Fjord-Larsen, Mads; Hansen, Frank Allan

    This paper identifies several problems with navigating and visualizing guided tours in traditional hypermedia systems. We discuss solutions to these problems, including the representation of guided tours as 3D metro maps with content preview. Issues regarding navigation and disorientation...

  11. The Visual System

    Medline Plus

    Full Text Available ... and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and ... National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education ...

  12. The Visual System

    Medline Plus

    Full Text Available ... and other programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of ... National Eye Health Education Program (NEHEP) Diabetic Eye Disease Education Program Glaucoma Education Program Low Vision Education ...

  13. The Visual System

    Medline Plus

    Full Text Available ... programs with respect to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems ... Pressroom Contacts Dustin Hays - Chief, Science Communication dustin.hays@nih.gov Anna Harper - Media Relations ...

  14. The Visual System

    Medline Plus

    Full Text Available ... to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and requirements of ... Pressroom Contacts Dustin Hays - Chief, Science Communication dustin.hays@nih.gov Anna Harper - Media Relations ...

  15. The Visual System

    Medline Plus

    Full Text Available ... to blinding eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and requirements of the blind.” ... Health Information Frequently asked questions ...

  16. The Visual System

    Medline Plus

    Full Text Available ... eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and ... Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding Extramural Research Division of ...

  17. The Visual System

    Science.gov (United States)

    ... eye diseases, visual disorders, mechanisms of visual function, preservation of sight, and the special health problems and ... Clinical Studies Publications Catalog Photos and Images Spanish Language Information Grants and Funding Extramural Research Division of ...

  18. NaviCell Web Service for network-based data visualization.

    Science.gov (United States)

    Bonnet, Eric; Viara, Eric; Kuperstein, Inna; Calzone, Laurence; Cohen, David P A; Barillot, Emmanuel; Zinovyev, Andrei

    2015-07-01

    Data visualization is an essential element of biological research, required for obtaining insights and formulating new hypotheses on mechanisms of health and disease. NaviCell Web Service is a tool for network-based visualization of 'omics' data which implements several data visual representation methods and utilities for combining them together. NaviCell Web Service uses Google Maps and semantic zooming to browse large biological network maps, represented in various formats, together with different types of the molecular data mapped on top of them. For achieving this, the tool provides standard heatmaps, barplots and glyphs as well as the novel map staining technique for grasping large-scale trends in numerical values (such as whole transcriptome) projected onto a pathway map. The web service provides a server mode, which allows automating visualization tasks and retrieving data from maps via RESTful (standard HTTP) calls. Bindings to different programming languages are provided (Python and R). We illustrate the purpose of the tool with several case studies using pathway maps created by different research groups, in which data visualization provides new insights into molecular mechanisms involved in systemic diseases such as cancer and neurodegenerative diseases. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Mechanical stress triggers cardiomyocyte autophagy through angiotensin II type 1 receptor-mediated p38MAP kinase independently of angiotensin II.

    Directory of Open Access Journals (Sweden)

    Li Lin

    Full Text Available Angiotensin II (Ang II type 1 (AT1 receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.

  20. Fluid mechanic assessment of the total cavopulmonary connection using magnetic resonance phase velocity mapping and digital particle image velocimetry.

    Science.gov (United States)

    Ensley, A E; Ramuzat, A; Healy, T M; Chatzimavroudis, G P; Lucas, C; Sharma, S; Pettigrew, R; Yoganathan, A P

    2000-01-01

    The total cavopulmonary connection (TCPC) is currently the most promising modification of the Fontan surgical repair for single ventricle congenital heart disease. The TCPC involves a surgical connection of the superior and inferior vena cavae directly to the left and right pulmonary arteries, bypassing the right heart. In the univentricular system, the ventricle experiences a workload which may be reduced by optimizing the cavae-to-pulmonary anastomosis. The hypothesis of this study was that the energetic efficiency of the connection is a consequence of the fluid dynamics which develop as a function of connection geometry. Magnetic resonance phase velocity mapping (MRPVM) and digital particle image velocimetry (DPIV) were used to evaluate the flow patterns in vitro in three prototype glass models of the TCPC: flared zero offset, flared 14 mm offset, and straight 21 mm offset. The flow field velocity along the symmetry plane of each model was chosen to elucidate the fluid mechanics of the connection as a function of the connection geometry and pulmonary artery flow split. The steady flow experiments were conducted at a physiologic cardiac output (4 L/min) over three left/right pulmonary flow splits (70/30, 50/50, and 30/70) while keeping the superior/inferior vena cavae flow ratio constant at 40/60. MRPVM, a noninvasive clinical technique for measuring flow field velocities, was compared to DPIV, an established in vitro fluid mechanic technique. A comparison between the results from both techniques showed agreement of large scale flow features, despite some discrepancies in the detailed flow fields. The absence of caval offset in the flared zero offset model resulted in significant caval flow collision at the connection site. In contrast, offsetting the cavae reduced the flow interaction and caused a vortex-like low velocity region between the caval inlets as well as flow disturbance in the pulmonary artery with the least total flow. A positive correlation was also

  1. GIS-Based Data Structure for Geological Mapping of Ceres — One Global Map Composed of 15 Map Sheets

    Science.gov (United States)

    Naß, A.; Dawn Mapping Team

    2017-06-01

    Deriving valid statements out of interpretative geological mapping is very time intensive. Another challenge is generating one map composed of several map sheets which presents a geologically-consistent and geometrical/visual comparable content.

  2. Mapping with Drupal

    CERN Document Server

    Palazzolo, Alan

    2011-01-01

    Build beautiful interactive maps on your Drupal website, and tell engaging visual stories with your data. This concise guide shows you how to create custom geographical maps from top to bottom, using Drupal 7 tools and out-of-the-box modules. You'll learn how mapping works in Drupal, with examples on how to use intuitive interfaces to map local events, businesses, groups, and other custom data. Although building maps with Drupal can be tricky, this book helps you navigate the system's complexities for creating sophisticated maps that match your site design. Get the knowledge and tools you ne

  3. Control of the strength of visual-motor transmission as the mechanism of rapid adaptation of priors for Bayesian inference in smooth pursuit eye movements.

    Science.gov (United States)

    Darlington, Timothy R; Tokiyama, Stefanie; Lisberger, Stephen G

    2017-08-01

    Bayesian inference provides a cogent account of how the brain combines sensory information with "priors" based on past experience to guide many behaviors, including smooth pursuit eye movements. We now demonstrate very rapid adaptation of the pursuit system's priors for target direction and speed. We go on to leverage that adaptation to outline possible neural mechanisms that could cause pursuit to show features consistent with Bayesian inference. Adaptation of the prior causes changes in the eye speed and direction at the initiation of pursuit. The adaptation appears after a single trial and accumulates over repeated exposure to a given history of target speeds and directions. The influence of the priors depends on the reliability of visual motion signals: priors are more effective against the visual motion signals provided by low-contrast vs. high-contrast targets. Adaptation of the direction prior generalizes to eye speed and vice versa, suggesting that both priors could be controlled by a single neural mechanism. We conclude that the pursuit system can learn the statistics of visual motion rapidly and use those statistics to guide future behavior. Furthermore, a model that adjusts the gain of visual-motor transmission predicts the effects of recent experience on pursuit direction and speed, as well as the specifics of the generalization between the priors for speed and direction. We suggest that Bayesian inference in pursuit behavior is implemented by distinctly non-Bayesian internal mechanisms that use the smooth eye movement region of the frontal eye fields to control of the gain of visual-motor transmission.NEW & NOTEWORTHY Bayesian inference can account for the interaction between sensory data and past experience in many behaviors. Here, we show, using smooth pursuit eye movements, that the priors based on past experience can be adapted over a very short time frame. We also show that a single model based on direction-specific adaptation of the strength of

  4. Visualizing post genomics data-sets on customized pathway maps by ProMeTra – aeration-dependent gene expression and metabolism of Corynebacterium glutamicum as an example

    Directory of Open Access Journals (Sweden)

    Hüser Andrea T

    2009-08-01

    Full Text Available Abstract Background The rapid progress of post-genomic analyses, such as transcriptomics, proteomics, and metabolomics has resulted in the generation of large amounts of quantitative data covering and connecting the complete cascade from genotype to phenotype for individual organisms. Various benefits can be achieved when these "Omics" data are integrated, such as the identification of unknown gene functions or the elucidation of regulatory networks of whole organisms. In order to be able to obtain deeper insights in the generated datasets, it is of utmost importance to present the data to the researcher in an intuitive, integrated, and knowledge-based environment. Therefore, various visualization paradigms have been established during the last years. The visualization of "Omics" data using metabolic pathway maps is intuitive and has been applied in various software tools. It has become obvious that the application of web-based and user driven software tools has great potential and benefits from the use of open and standardized formats for the description of pathways. Results In order to combine datasets from heterogeneous "Omics" sources, we present the web-based ProMeTra system that visualizes and combines datasets from transcriptomics, proteomics, and metabolomics on user defined metabolic pathway maps. Therefore, structured exchange of data with our "Omics" applications Emma 2, Qupe and MeltDB is employed. Enriched SVG images or animations are generated and can be obtained via the user friendly web interface. To demonstrate the functionality of ProMeTra, we use quantitative data obtained during a fermentation experiment of the L-lysine producing strain Corynebacterium glutamicum DM1730. During fermentation, oxygen supply was switched off in order to perturb the system and observe its reaction. At six different time points, transcript abundances, intracellular metabolite pools, as well as extracellular glucose, lactate, and L-lysine levels

  5. TOXMAP®: Environmental Health Maps

    Data.gov (United States)

    U.S. Department of Health & Human Services — TOXMAP® is a Geographic Information System (GIS) that uses maps of the United States and Canada to help users visually explore data primarily from the EPA's Toxics...

  6. The Atypical MAP Kinase SWIP-13/ERK8 Regulates Dopamine Transporters through a Rho-Dependent Mechanism.

    Science.gov (United States)

    Bermingham, Daniel P; Hardaway, J Andrew; Refai, Osama; Marks, Christian R; Snider, Sam L; Sturgeon, Sarah M; Spencer, William C; Colbran, Roger J; Miller, David M; Blakely, Randy D

    2017-09-20

    The neurotransmitter dopamine (DA) regulates multiple behaviors across phylogeny, with disrupted DA signaling in humans associated with addiction, attention-deficit/ hyperactivity disorder, schizophrenia, and Parkinson's disease. The DA transporter (DAT) imposes spatial and temporal limits on DA action, and provides for presynaptic DA recycling to replenish neurotransmitter pools. Molecular mechanisms that regulate DAT expression, trafficking, and function, particularly in vivo, remain poorly understood, though recent studies have implicated rho-linked pathways in psychostimulant action. To identify genes that dictate the ability of DAT to sustain normal levels of DA clearance, we pursued a forward genetic screen in Caenorhabditis elegans based on the phenotype swimming-induced paralysis (Swip), a paralytic behavior observed in hermaphrodite worms with loss-of-function dat-1 mutations. Here, we report the identity of swip-13, which encodes a highly conserved ortholog of the human atypical MAP kinase ERK8. We present evidence that SWIP-13 acts presynaptically to insure adequate levels of surface DAT expression and DA clearance. Moreover, we provide in vitro and in vivo evidence supporting a conserved pathway involving SWIP-13/ERK8 activation of Rho GTPases that dictates DAT surface expression and function.SIGNIFICANCE STATEMENT Signaling by the neurotransmitter dopamine (DA) is tightly regulated by the DA transporter (DAT), insuring efficient DA clearance after release. Molecular networks that regulate DAT are poorly understood, particularly in vivo Using a forward genetic screen in the nematode Caenorhabditis elegans, we implicate the atypical mitogen activated protein kinase, SWIP-13, in DAT regulation. Moreover, we provide in vitro and in vivo evidence that SWIP-13, as well as its human counterpart ERK8, regulate DAT surface availability via the activation of Rho proteins. Our findings implicate a novel pathway that regulates DA synaptic availability and that may

  7. Visualization and analysis of balancing of the slider-crank mechanism on an elastic foundation in the mining tunneling machines

    Science.gov (United States)

    Skachkova, L. A.; Isaeva, E. S.; Feh, A. I.; Safyannikova, V. I.

    2017-01-01

    The research rationale aimed at development and use of the slider-crank mechanism in the mining equipment is justified. The advantages, as well as functional, engineering and technological features are determined for the feeder in the tunneling machine. The development ways of the structural design solutions of the slider-crank mechanism in the mining machines are specified. The analysis for balancing of the mechanism on an elastic foundation with special pendulums attached to the crankshaft is done. The calculations to justify balancing using the pendulum are done. Modeling of the slider-crank mechanism is realized.

  8. NEON VISUALIZATION ENVIRONMENT

    Science.gov (United States)

    2017-07-28

    INTRODUCTION .................................................................................................................. 1 3. METHODS... INTRODUCTION Neon is a novel departure from conventional information visualization: the goal was not to develop a typical visualization toolkit but instead...development philosophies . We assisted in creating a demo using Neon and VINI STTR tools as a visualization mechanism for MUSE. With Memex, we

  9. Visual stability.

    Science.gov (United States)

    Melcher, David

    2011-02-27

    Our vision remains stable even though the movements of our eyes, head and bodies create a motion pattern on the retina. One of the most important, yet basic, feats of the visual system is to correctly determine whether this retinal motion is owing to real movement in the world or rather our own self-movement. This problem has occupied many great thinkers, such as Descartes and Helmholtz, at least since the time of Alhazen. This theme issue brings together leading researchers from animal neurophysiology, clinical neurology, psychophysics and cognitive neuroscience to summarize the state of the art in the study of visual stability. Recently, there has been significant progress in understanding the limits of visual stability in humans and in identifying many of the brain circuits involved in maintaining a stable percept of the world. Clinical studies and new experimental methods, such as transcranial magnetic stimulation, now make it possible to test the causal role of different brain regions in creating visual stability and also allow us to measure the consequences when the mechanisms of visual stability break down.

  10. Visualizing Disease Associations: Graphic Analysis of Frequency Distributions as a Function of Age Using Moving Average Plots (MAP) with Application to Alzheimer's and Parkinson's Disease

    OpenAIRE

    Payami, Haydeh; Kay, Denise M.; Zabetian, Cyrus P.; Schellenberg, Gerard D.; Factor, Stewart A.; McCulloch, Colin C.

    2010-01-01

    Age-related variation in marker frequency can be a confounder in association studies, leading to both false positive and false negative findings and subsequently to inconsistent reproducibility. We have developed a simple method, based on a novel extension of moving average plots (MAP), which allows investigators to inspect the frequency data for hidden age-related variations. MAP uses the standard case-control association data and generates a birds-eye view of the frequency distributions acr...

  11. Volume Tracking: A new method for quantitative assessment and visualization of intracardiac blood flow from three-dimensional, time-resolved, three-component magnetic resonance velocity mapping

    Directory of Open Access Journals (Sweden)

    Arheden Håkan

    2011-04-01

    Full Text Available Abstract Background Functional and morphological changes of the heart influence blood flow patterns. Therefore, flow patterns may carry diagnostic and prognostic information. Three-dimensional, time-resolved, three-directional phase contrast cardiovascular magnetic resonance (4D PC-CMR can image flow patterns with unique detail, and using new flow visualization methods may lead to new insights. The aim of this study is to present and validate a novel visualization method with a quantitative potential for blood flow from 4D PC-CMR, called Volume Tracking, and investigate if Volume Tracking complements particle tracing, the most common visualization method used today. Methods Eight healthy volunteers and one patient with a large apical left ventricular aneurysm underwent 4D PC-CMR flow imaging of the whole heart. Volume Tracking and particle tracing visualizations were compared visually side-by-side in a visualization software package. To validate Volume Tracking, the number of particle traces that agreed with the Volume Tracking visualizations was counted and expressed as a percentage of total released particles in mid-diastole and end-diastole respectively. Two independent observers described blood flow patterns in the left ventricle using Volume Tracking visualizations. Results Volume Tracking was feasible in all eight healthy volunteers and in the patient. Visually, Volume Tracking and particle tracing are complementary methods, showing different aspects of the flow. When validated against particle tracing, on average 90.5% and 87.8% of the particles agreed with the Volume Tracking surface in mid-diastole and end-diastole respectively. Inflow patterns in the left ventricle varied between the subjects, with excellent agreement between observers. The left ventricular inflow pattern in the patient differed from the healthy subjects. Conclusion Volume Tracking is a new visualization method for blood flow measured by 4D PC-CMR. Volume Tracking

  12. Innovative Visualization Techniques applied to a Flood Scenario

    Science.gov (United States)

    Falcão, António; Ho, Quan; Lopes, Pedro; Malamud, Bruce D.; Ribeiro, Rita; Jern, Mikael

    2013-04-01

    The large and ever-increasing amounts of multi-dimensional, time-varying and geospatial digital information from multiple sources represent a major challenge for today's analysts. We present a set of visualization techniques that can be used for the interactive analysis of geo-referenced and time sampled data sets, providing an integrated mechanism and that aids the user to collaboratively explore, present and communicate visually complex and dynamic data. Here we present these concepts in the context of a 4 hour flood scenario from Lisbon in 2010, with data that includes measures of water column (flood height) every 10 minutes at a 4.5 m x 4.5 m resolution, topography, building damage, building information, and online base maps. Techniques we use include web-based linked views, multiple charts, map layers and storytelling. We explain two of these in more detail that are not currently in common use for visualization of data: storytelling and web-based linked views. Visual storytelling is a method for providing a guided but interactive process of visualizing data, allowing more engaging data exploration through interactive web-enabled visualizations. Within storytelling, a snapshot mechanism helps the author of a story to highlight data views of particular interest and subsequently share or guide others within the data analysis process. This allows a particular person to select relevant attributes for a snapshot, such as highlighted regions for comparisons, time step, class values for colour legend, etc. and provide a snapshot of the current application state, which can then be provided as a hyperlink and recreated by someone else. Since data can be embedded within this snapshot, it is possible to interactively visualize and manipulate it. The second technique, web-based linked views, includes multiple windows which interactively respond to the user selections, so that when selecting an object and changing it one window, it will automatically update in all the other

  13. The interaction of visual, vestibular and extra-retinal mechanisms in the control of head and gaze during head-free pursuit.

    Science.gov (United States)

    Ackerley, Rochelle; Barnes, Graham R

    2011-04-01

    The ability to co-ordinate the eyes and head when tracking moving objects is important for survival. Tracking with eyes alone is controlled by both visually dependent and extra-retinal mechanisms, the latter sustaining eye movement during target extinction. We investigated how the extra-retinal component develops at the beginning of randomised responses during head-free pursuit and how it interacts with the vestibulo-ocular reflex (VOR). Subjects viewed horizontal step-ramp stimuli which occurred in pairs of identical velocity; velocity was randomised between pairs, ranging from ±5 to 40 deg s−1. In the first of each pair (short-ramp extinction) the target was visible for only 150 ms. In the second (initial extinction), after a randomised fixation period, the target was extinguished at motion onset, remaining invisible for 750 ms before reappearing for the last 200 ms of motion. Subjects used motion information acquired in the short-ramp extinction presentation to track the target from the start of unseen motion in the initial extinction presentation, using extra-retinal drive to generate smooth gaze and head movements scaled to target velocity. Gaze velocity rose more slowly than when visually driven, but had similar temporal development in head-free and head-fixed conditions. The difference in eye-in-head velocity between head-fixed and head-free conditions was closely related to head velocity throughout its trajectory, implying that extra-retinal drive was responsible for countermanding the VOR in the absence of vision. Thus, the VOR apparently remained active during head-free pursuit with near-unity gain. Evidence also emerged that head movements are not directly controlled by visual input, but by internal estimation mechanisms similar to those controlling gaze.

  14. Once you feel it, you see it : Insula and sensory-motor contribution to visual awareness for fearful bodies in parietal extinction

    NARCIS (Netherlands)

    Tamietto, M.; Cauda, F.; Celeghin, A.; Diano, M.; Costa, T.; Cossa, F.M.; Sacco, K; Duca, S.; Germiniani, G.; de Gelder, B.

    2014-01-01

    The interplay between the neural mechanisms of visual awareness and those involved in emotion processing and the mapping of related somatic changes remains unclear. To address this issue we studied one patient with visual extinction following right parietal damage, in a combined behavioral,

  15. Study of the mapping mechanism of ferroelectric domains with the scanning force microscope; Untersuchung der Abbildungsmechanismen ferroelektrischer Domaenen mit dem Rasterkraftmikroskop

    Energy Technology Data Exchange (ETDEWEB)

    Jungk, T.

    2006-12-15

    The piezo-force microscopy (PFM) allows the mapping of ferroelectric domains until the nanometer range. In spite of its simple function principle it was hitherto not completely understood. In ordser to develop the PFM further to a quantitative analysis method its methodical aspects were analyzed. It was shown that the fundamental mapping mechanism is based on the inverse piezo-effect. Different artefacts to be found in the literature could therefore be reduced to a measurement background. Furthermore the influence of the electrode geometry was analyzed. The width of doamin walls was systematically measured and simulated with a mode, whereby a maximal resolution of 17 nm was reached. By the development of a correction procedure for the exact detection of the forces acting on the spring-beam the lateral signals measured on domain walls could by newly interpreted. So the ''Lateral Electrostatic Force Microscopy'' was developed.

  16. Deep Mapping the Biome: The Biology of Place in Don Gayton's "The Wheatgrass Mechanism" and John Janovy Jr.'s "Dunwoody Pond"

    Science.gov (United States)

    Maher, Susan Naramore

    2005-01-01

    The term "deep map" is the invention of writer William Least Heat-Moon, whose extended essay "PrairyErth (a deep map)" has given definition to this form. Deep-map writing is marked by its intertextual, interdisciplinary, and multivocal nature. It is also self-consciously cartographic, presenting maps, following maps, and redrawing maps. Deep…

  17. Modeling, analysis, and visualization of anisotropy

    CERN Document Server

    Özarslan, Evren; Hotz, Ingrid

    2017-01-01

    This book focuses on the modeling, processing and visualization of anisotropy, irrespective of the context in which it emerges, using state-of-the-art mathematical tools. As such, it differs substantially from conventional reference works, which are centered on a particular application. It covers the following topics: (i) the geometric structure of tensors, (ii) statistical methods for tensor field processing, (iii) challenges in mapping neural connectivity and structural mechanics, (iv) processing of uncertainty, and (v) visualizing higher-order representations. In addition to original research contributions, it provides insightful reviews. This multidisciplinary book is the sixth in a series that aims to foster scientific exchange between communities employing tensors and other higher-order representations of directionally dependent data. A significant number of the chapters were co-authored by the participants of the workshop titled Multidisciplinary Approaches to Multivalued Data: Modeling, Visualization,...

  18. Value Stream Mapping of Rope Manufacturing: A Case Study

    National Research Council Canada - National Science Library

    Yuvamitra, Korakot; Lee, Jim; Dong, Kanjicai

    2017-01-01

    .... One way of achieving constant process improvement is through value stream mapping. Value stream mapping is used to visualize the current processes for easier understanding and problem identification...

  19. Visual Impairment

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Visual Impairment KidsHealth / For Teens / Visual Impairment What's in ... with the brain, making vision impossible. What Is Visual Impairment? Many people have some type of visual ...

  20. Visual field

    Science.gov (United States)

    Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam ... Confrontation visual field exam. This is a quick and basic check of the visual field. The health care provider ...

  1. Mechanisms of species divergence through visual adaptation and sexual selection:Perspectives from a cichlid model system

    Directory of Open Access Journals (Sweden)

    Martine E. MAAN, Ole SEEHAUSEN

    2010-06-01

    Full Text Available The theory of ecological speciation suggests that assortative mating evolves most easily when mating preferences are directly linked to ecological traits that are subject to divergent selection. Sensory adaptation can play a major role in this process, because selective mating is often mediated by sexual signals: bright colours, complex song, pheromone blends and so on. When divergent sensory adaptation affects the perception of such signals, mating patterns may change as an immediate consequence. Alternatively, mating preferences can diverge as a result of indirect effects: assortative mating may be promoted by selection against intermediate phenotypes that are maladapted to their (sensory environment. For Lake Victoria cichlids, the visual environment constitutes an important selective force that is heterogeneous across geographical and water depth gradients. We investigate the direct and indirect effects of this heterogeneity on the evolution of female preferences for alternative male nuptial colours (red and blue in the genus Pundamilia. Here, we review the current evidence for divergent sensory drive in this system, extract general principles, and discuss future perspectives [Current Zoology 56 (3: 285–299, 2010].

  2. Mapping out Map Libraries

    Directory of Open Access Journals (Sweden)

    Ferjan Ormeling

    2008-09-01

    Full Text Available Discussing the requirements for map data quality, map users and their library/archives environment, the paper focuses on the metadata the user would need for a correct and efficient interpretation of the map data. For such a correct interpretation, knowledge of the rules and guidelines according to which the topographers/cartographers work (such as the kind of data categories to be collected, and the degree to which these rules and guidelines were indeed followed are essential. This is not only valid for the old maps stored in our libraries and archives, but perhaps even more so for the new digital files as the format in which we now have to access our geospatial data. As this would be too much to ask from map librarians/curators, some sort of web 2.0 environment is sought where comments about data quality, completeness and up-to-dateness from knowledgeable map users regarding the specific maps or map series studied can be collected and tagged to scanned versions of these maps on the web. In order not to be subject to the same disadvantages as Wikipedia, where the ‘communis opinio’ rather than scholarship, seems to be decisive, some checking by map curators of this tagged map use information would still be needed. Cooperation between map curators and the International Cartographic Association ( ICA map and spatial data use commission to this end is suggested.

  3. Journey Mapping the User Experience

    Science.gov (United States)

    Samson, Sue; Granath, Kim; Alger, Adrienne

    2017-01-01

    This journey-mapping pilot study was designed to determine whether journey mapping is an effective method to enhance the student experience of using the library by assessing our services from their point of view. Journey mapping plots a process or service to produce a visual representation of a library transaction--from the point at which the…

  4. Mapping of Force: A Process of Parametric Design from the Prototype Mechanical Mechanism to the Structural Form of a Woven HYPAR Shell

    Directory of Open Access Journals (Sweden)

    Lin Kang Qiang

    2016-01-01

    Full Text Available From a new perspective of structural engineering, with the integration of the 1st and 3rd principal stress distribution of HYPAR shell structure into the selection of texture variation zone, this paper analyzes and demonstrates the key questions of how to establish the association between the force-flow, the texture direction and the form parameters; how to develop a dynamic, performance-optimized and adaptive iteration model of HYPAR shell structural form by setting and adjusting structurally sensitive parameters; and how to realize the process of parametric design from the mechanical mechanism of the prototype to the structural form of the woven HYPAR shell.

  5. Andreas Acrivos Dissertation Prize Lecture: Quantum Mechanics meets Fluid Dynamics: Visualization of Vortex Reconnection in Superfluid Helium

    Science.gov (United States)

    Paoletti, Matthew

    2010-11-01

    Long-range quantum order underlies a number of related physical phenomena including superfluidity, superconductivity and Bose-Einstein condensation. While superfluidity in helium-4 was one of the earliest discovered, it is not the best understood, owing to the strong interactions present (making theoretical progress difficult) and the lack of local experimental probes. Quantum fluids, such as superfluid helium-4, are typically described as a mixture of two interpenetrating fluids with distinct velocity fields: a viscous normal fluid akin to water and an inviscid superfluid exhibiting long-range quantum order. In this "two-fluid model," there is no conventional viscous dissipation in the superfluid component and vorticity is confined to atomically-thin vortices with quantized circulation. Turbulence may occur in either fluid component with turbulence in the superfluid exhibiting a complex tangle of quantized vortices, as first envisioned by Feynman. Approximately five years ago, our group discovered that micron-sized hydrogen particles may be used for flow visualization in superfluid helium-4. The particles can trace the motions of the normal fluid or be trapped by the quantized vortices, which enables one to characterize the dynamics of both the normal fluid and superfluid components for the first time. By directly observing and tracking these particles, we have directly confirmed the two-fluid model, observed vortex rings and quantized vortex reconnection, characterized thermal counterflows, and observed the very peculiar nature of quantum turbulence. One of many surprising observations is the existence of power-law tails in the probability distribution of velocities in quantum turbulence, which are in stark contrast to the Gaussian distributions typical of classical fluid turbulence.

  6. A methodology for small scale rural land use mapping in semi-arid developing countries using orbital imagery. Part 6: A low-cost method for land use mapping using simple visual techniques of interpretation. [Spain

    Science.gov (United States)

    Vangenderen, J. L. (Principal Investigator); Lock, B. F.

    1976-01-01

    The author has identified the following significant results. It was found that color composite transparencies and monocular magnification provided the best base for land use interpretation. New methods for determining optimum sample sizes and analyzing interpretation accuracy levels were developed. All stages of the methodology were assessed, in the operational sense, during the production of a 1:250,000 rural land use map of Murcia Province, Southeast Spain.

  7. Fluid Mechanics Prize-Otto Laporte Lecture: The Art of Mixing with an Admixture of Art: Fluids, Solids, and Visual Imagination

    Science.gov (United States)

    Ottino, Julio Mario

    2008-11-01

    Arguably, fluid dynamics is intimately linked with visual imagination more than any other branch of physical sciences. A particular example is mixing. Fluid mixing, and under more limited circumstances, granular mixing, can be placed in the framework of dynamical systems and a geometric viewpoint. On the fluid mixing side, the physical connection can be traced back to the stretching and folding of fluid elements and possibility of representation motions in terms of transformations. This opens a wealth of possibilities --- the mathematical machinery of dynamical systems on the theory side, and the possibility of inventing devices on the practical side. There are notable differences as well: granular materials un-mix or segregate, often spectacularly so, and some aspects of segregation can also be incorporated in the mathematical framework. A technical review will highlight key points in both areas -- experiments, applications, and the many branches that have taken root since the mid-1980s. However, much of this could have taken place sooner. The basic mechanisms and key experimental results in both areas were identified early: the stretching and folding mechanism of mixing was pointed out by Osborne Reynolds in 1893-1895, and a key segregation mechanism of granular mixtures was noted by Yositisi Oyama in 1939. In what may appear surprising on a first viewing, these leads were not followed. Ideas, in order to be embraced, need to fit with the canonical knowledge of the times.

  8. Transgenic Analysis of the Leishmania MAP Kinase MPK10 Reveals an Auto-inhibitory Mechanism Crucial for Stage-Regulated Activity and Parasite Viability

    DEFF Research Database (Denmark)

    Cayla, M.; Rachidi, N.; Leclercq, O.

    2014-01-01

    though Leishmania mitogen-activated protein kinases (MAPKs) have been linked previously to environmentally induced differentiation and virulence. Here, we unravel highly unusual regulatory mechanisms for Leishmania MAP kinase 10 (MPK10). Using a transgenic approach, we demonstrate that MPK10 is stage......-specifically regulated, as its kinase activity increases during the promastigote to amastigote conversion. However, unlike canonical MAPKs that are activated by dual phosphorylation of the regulatory TxY motif in the activation loop, MPK10 activation is independent from the phosphorylation of the tyrosine residue, which...... is largely constitutive. Removal of the last 46 amino acids resulted in significantly enhanced MPK10 activity both for the recombinant and transgenic protein, revealing that MPK10 is regulated by an auto-inhibitory mechanism. Over-expression of this hyperactive mutant in transgenic parasites led...

  9. Visual Semiotics & Uncertainty Visualization: An Empirical Study.

    Science.gov (United States)

    MacEachren, A M; Roth, R E; O'Brien, J; Li, B; Swingley, D; Gahegan, M

    2012-12-01

    This paper presents two linked empirical studies focused on uncertainty visualization. The experiments are framed from two conceptual perspectives. First, a typology of uncertainty is used to delineate kinds of uncertainty matched with space, time, and attribute components of data. Second, concepts from visual semiotics are applied to characterize the kind of visual signification that is appropriate for representing those different categories of uncertainty. This framework guided the two experiments reported here. The first addresses representation intuitiveness, considering both visual variables and iconicity of representation. The second addresses relative performance of the most intuitive abstract and iconic representations of uncertainty on a map reading task. Combined results suggest initial guidelines for representing uncertainty and discussion focuses on practical applicability of results.

  10. Resistance to gray leaf spot of maize: genetic architecture and mechanisms elucidated through nested association mapping and near-isogenic line analysis.

    Directory of Open Access Journals (Sweden)

    Jacqueline M Benson

    2015-03-01

    Full Text Available Gray leaf spot (GLS, caused by Cercospora zeae-maydis and Cercospora zeina, is one of the most important diseases of maize worldwide. The pathogen has a necrotrophic lifestyle and no major genes are known for GLS. Quantitative resistance, although poorly understood, is important for GLS management. We used genetic mapping to refine understanding of the genetic architecture of GLS resistance and to develop hypotheses regarding the mechanisms underlying quantitative disease resistance (QDR loci. Nested association mapping (NAM was used to identify 16 quantitative trait loci (QTL for QDR to GLS, including seven novel QTL, each of which demonstrated allelic series with significant effects above and below the magnitude of the B73 reference allele. Alleles at three QTL, qGLS1.04, qGLS2.09, and qGLS4.05, conferred disease reductions of greater than 10%. Interactions between loci were detected for three pairs of loci, including an interaction between iqGLS4.05 and qGLS7.03. Near-isogenic lines (NILs were developed to confirm and fine-map three of the 16 QTL, and to develop hypotheses regarding mechanisms of resistance. qGLS1.04 was fine-mapped from an interval of 27.0 Mb to two intervals of 6.5 Mb and 5.2 Mb, consistent with the hypothesis that multiple genes underlie highly significant QTL identified by NAM. qGLS2.09, which was also associated with maturity (days to anthesis and with resistance to southern leaf blight, was narrowed to a 4-Mb interval. The distance between major leaf veins was strongly associated with resistance to GLS at qGLS4.05. NILs for qGLS1.04 were treated with the C. zeae-maydis toxin cercosporin to test the role of host-specific toxin in QDR. Cercosporin exposure increased expression of a putative flavin-monooxygenase (FMO gene, a candidate detoxification-related gene underlying qGLS1.04. This integrated approach to confirming QTL and characterizing the potential underlying mechanisms advances the understanding of QDR and will

  11. Co-lateralized bilingual mechanisms for reading in single and dual language contexts: evidence from visual half-field processing of action words in proficient bilinguals

    Directory of Open Access Journals (Sweden)

    Marlena eKrefta

    2015-08-01

    Full Text Available When reading, proficient bilinguals seem to engage the same cognitive circuits regardless of the language in use. Yet, whether or not such ‘bilingual’ mechanisms would be lateralized in the same way in distinct – single or dual – language contexts is a question for debate. To fill this gap, we tested 18 highly proficient Polish (L1 – English (L2 childhood bilinguals whose task was to read aloud one of the two laterally presented action verbs, one stimulus per visual half field. While in the single-language blocks only L1 or L2 words were shown, in the subsequent mixed-language blocks words from both languages were concurrently displayed. All stimuli were presented for 217 ms followed by masks in which letters were replaced with hash marks. Since in non-simultaneous bilinguals the control of language, skilled actions (including reading, and representations of action concepts are typically left lateralized, the vast majority of our participants showed the expected, significant right visual field advantage for L1 and L2, both for accuracy and response times. The observed effects were nevertheless associated with substantial variability in the strength of the lateralization of the mechanisms involved. Moreover, although it could be predicted that participants’ performance should be better in a single-language context, accuracy was significantly higher and response times were significantly shorter in a dual-language context, irrespective of the language tested. Finally, for both accuracy and response times, there were significant positive correlations between the laterality indices (LIs of both languages independent of the context, with a significantly greater left-sided advantage for L1 vs. L2 in the mixed-language blocks, based on LIs calculated for response times. Thus, despite similar representations of the two languages in the bilingual brain, these results also point to the functional separation of L1 and L2 in the dual

  12. Mechanics

    CERN Document Server

    Hartog, J P Den

    1961-01-01

    First published over 40 years ago, this work has achieved the status of a classic among introductory texts on mechanics. Den Hartog is known for his lively, discursive and often witty presentations of all the fundamental material of both statics and dynamics (and considerable more advanced material) in new, original ways that provide students with insights into mechanical relationships that other books do not always succeed in conveying. On the other hand, the work is so replete with engineering applications and actual design problems that it is as valuable as a reference to the practicing e

  13. Mapping a Better Vintage

    Science.gov (United States)

    2003-01-01

    Vineyards such as those located in California's Napa Valley tend to be subdivided into relatively large fields or blocks that often encompass heterogeneous physical conditions. Since growers typically treat the entire block as a single minimum management unit for cultivation and harvest, mapping and monitoring the variability within a block is a concern. Over the last decade, an increasing number of vineyard managers have utilized digital remote sensing and geographic information systems (GIS) to visualize the variability within their blocks. With computer software designed to overlay remotely sensed imagery with environmental and agronomic geographic data on a map, GIS helps growers recognize and explain patterns that might not have been obvious otherwise. GIS can also serve as a valuable archiving mechanism for future reference. To further develop the use of image technology and GIS for vineyard management support, NASA's Earth Science Enterprise partnered with the U.S. wine and commercial remote sensing industries for a project known as the Viticultural Integration of NASA Technologies for Assessment of the Grapevine Environment (VINTAGE). With project investigators from NASA's Ames Research Center, the California State University at Monterey Bay, and the University of Montana, several prototype products have been developed to support agricultural decisions concerning canopy management and irrigation practice. One key VINTAGE aspect involved the evaluation of satellite and airborne multispectral imagery for delineation of sub-block management zones within a vineyard.

  14. Mapping dynamical mechanical properties of osteonal bone by scanning acoustic microscopy in time-of-flight mode.

    Science.gov (United States)

    Blouin, Stéphane; Puchegger, Stephan; Roschger, Andreas; Berzlanovich, Andrea; Fratzl, Peter; Klaushofer, Klaus; Roschger, Paul

    2014-06-01

    An important determinant of mechanical properties of bone is Young's modulus and its variation in individual osteons of cortical bone tissue. Its mechanical behavior also depends on deformation rate owing to its visco- or poroelastic properties. We developed a method to measure dynamical mechanical properties of bulk bone tissue at osteonal level based on scanning acoustic microscopy (SAM) using time-of-flight (TOF) measurements in combination with quantitative backscattered electron imaging (qBEI). SAM-TOF yields local sound velocities and qBEI corresponding material densities together providing elastic properties. Osteons (n=55) were measured in three human femoral diaphyseal ground bone sections (∼ 30 µm in thickness). In addition, subchondral bone and mineralized articular cartilage were investigated. The mean mineral contents, the mean sound velocities, and the mean elastic modulus of the osteons ranged from 20 to 26 wt%, from 3,819 to 5,260 m/s, and from 21 to 44 GPa, respectively. There was a strong positive correlation between material density and sound velocity (Pearson's r=0.701; pSound velocities between cartilage and bone was similar, though material density was higher in cartilage (+4.46%, p<0.0001). These results demonstrate the power of SAM-TOF to estimate dynamic mechanical properties of the bone materials at the osteonal level.

  15. Comparison of lasers used in stapedotomy using specialized visualization techniques for mechanical and thermal effects in an inner ear model

    Science.gov (United States)

    Kamalski, Digna M. A.; Verdaasdonk, Rudolf M.; de Boorder, Tjeerd; Grolman, Wilko

    2011-03-01

    The outcome of stapedotomy depends on several surgical steps. Using laser light, the ossicular chain can be handled and the oval window can be punctured with a non-touch method. Various lasers are being used or considered, however, it is not clear which settings and characteristics will contribute to optimal or adverse effects (vestibule damage and loss hearing frequencies). Using a unique high speed thermal imaging setup based on Schlieren techniques, the mechanical and thermal effects during laser stapedotomy were studied in an inner ear model consisting of human, fresh frozen stapes positioned on a liquid filled cavity in a gel cast. The cw KTP (532 nm), cw CO2 (10.6 μm), cw Thulium (2.0 μm), pulsed Er,Cr;YSGG (2.78 μm) coupled to special fiber delivery systems were applied at typical clinical settings for comparison. The imaging techniques provided a good insight in the extent of heat conduction beneath the footplate and (explosive) vapour formation on both sides. For the pulsed laser modes, explosive vapour expansion can to be controlled with optimized pulse energies while for continuous wave lasers the thermal effects can be controlled with the pulse length and repetition rate. The fluence at the tip of the delivery system and the distance to the footplate has a major impact on the ablation effect. The pulsed IR lasers with fiber delivery show to be promising for a controlled stapedotomy.

  16. Visualization of neonatal lung injury associated with mechanical ventilation using x-ray dark-field radiography

    Science.gov (United States)

    Yaroshenko, Andre; Pritzke, Tina; Koschlig, Markus; Kamgari, Nona; Willer, Konstantin; Gromann, Lukas; Auweter, Sigrid; Hellbach, Katharina; Reiser, Maximilian; Eickelberg, Oliver; Pfeiffer, Franz; Hilgendorff, Anne

    2016-04-01

    Mechanical ventilation (MV) and supplementation of oxygen-enriched gas, often needed in postnatal resuscitation procedures, are known to be main risk factors for impaired pulmonary development in the preterm and term neonates. Unfortunately, current imaging modalities lack in sensitivity for the detection of early stage lung injury. The present study reports a new imaging approach for diagnosis and staging of early lung injury induced by MV and hyperoxia in neonatal mice. The imaging method is based on the Talbot-Lau x-ray grating interferometry that makes it possible to quantify the x-ray small-angle scattering on the air-tissue interfaces. This so-called dark-field signal revealed increasing loss of x-ray small-angle scattering when comparing images of neonatal mice undergoing hyperoxia and MV-O2 with animals kept at room air. The changes in the dark field correlated well with histologic findings and provided superior differentiation than conventional x-ray imaging and lung function testing. The results suggest that x-ray dark-field radiography is a sensitive tool for assessing structural changes in the developing lung. In the future, with further technical developments x-ray dark-field imaging could be an important tool for earlier diagnosis and sensitive monitoring of lung injury in neonates requiring postnatal oxygen or ventilator therapy.

  17. Visual imagery without visual perception: lessons from blind subjects

    Science.gov (United States)

    Bértolo, Helder

    2014-08-01

    The question regarding visual imagery and visual perception remain an open issue. Many studies have tried to understand if the two processes share the same mechanisms or if they are independent, using different neural substrates. Most research has been directed towards the need of activation of primary visual areas during imagery. Here we review some of the works providing evidence for both claims. It seems that studying visual imagery in blind subjects can be used as a way of answering some of those questions, namely if it is possible to have visual imagery without visual perception. We present results from the work of our group using visual activation in dreams and its relation with EEG's spectral components, showing that congenitally blind have visual contents in their dreams and are able to draw them; furthermore their Visual Activation Index is negatively correlated with EEG alpha power. This study supports the hypothesis that it is possible to have visual imagery without visual experience.

  18. Automatic generation of tourist maps

    OpenAIRE

    Grabler, Floraine; Agrawala, Maneesh; Sumner, Robert W.; Pauly, Mark

    2008-01-01

    Tourist maps are essential resources for visitors to an unfamiliar city because they visually highlight landmarks and other points of interest. Yet, hand-designed maps are static representations that cannot adapt to the needs and tastes of the individual tourist. In this paper we present an automated system for designing tourist maps that selects and highlights the information that is most important to tourists. Our system determines the salience of map elements using bottom-up vision-based i...

  19. Neural computation of visual imaging based on Kronecker product in the primary visual cortex

    Directory of Open Access Journals (Sweden)

    Guozheng Yao

    2010-03-01

    that the function of cortical column in cortex V1 is considered as the basic unit of visual image processing (such unit can implement basic multiplication of visual primitives, such as contour, line, and edge, rather than a set of tiled array filter. Fourier Transformation is replaced with Kronecker product, which greatly reduces the computational complexity. The neurobiological basis of this idea is that a visual image can be represented as a linear combination of orderly orthogonal primitive image containing some local feature. In the visual pathway, the image patches are topographically mapped onto cortex V1 through parallel multi-channels and then are processed independently by functional columns. Clearly, the above new perspective has some reference significance to exploring the neural mechanisms on the human visual information processing.

  20. Helicopter visual aid system

    Science.gov (United States)

    Baisley, R. L.

    1973-01-01

    The helicopter visual aid system has been built and flight tested in situations representative of actual flight missions. The mechanisms discussed contributed greatly to the successful performance of the system throughout the 160 hours of flight testing. It has demonstrated that the visual aid concept can provide improved daytime visual capability, greatly improved nighttime capability, surveillance from greater distances and/or altitudes, covert operation at night through the use of the IR searchlight, and a photographic recording at the scene being viewed.