Chest CT window settings with multiscale adaptive histogram equalization: pilot study.

PubMed

Fayad, Laura M; Jin, Yinpeng; Laine, Andrew F; Berkmen, Yahya M; Pearson, Gregory D; Freedman, Benjamin; Van Heertum, Ronald

2002-06-01

Multiscale adaptive histogram equalization (MAHE), a wavelet-based algorithm, was investigated as a method of automatic simultaneous display of the full dynamic contrast range of a computed tomographic image. Interpretation times were significantly lower for MAHE-enhanced images compared with those for conventionally displayed images. Diagnostic accuracy, however, was insufficient in this pilot study to allow recommendation of MAHE as a replacement for conventional window display.

Display of high dynamic range images under varying viewing conditions

NASA Astrophysics Data System (ADS)

Borer, Tim

2017-09-01

Recent demonstrations of high dynamic range (HDR) television have shown that superb images are possible. With the emergence of an HDR television production standard (ITU-R Recommendation BT.2100) last year, HDR television production is poised to take off. However research to date has focused principally on HDR image display only under "dark" viewing conditions. HDR television will need to be displayed at varying brightness and under varying illumination (for example to view sport in daytime or on mobile devices). We know, from common practice with conventional TV, that the rendering intent (gamma) should change under brighter conditions, although this is poorly quantified. For HDR the need to render images under varying conditions is all the more acute. This paper seeks to explore the issues surrounding image display under varying conditions. It also describes how visual adaptation is affected by display brightness, surround illumination, screen size and viewing distance. Existing experimental results are presented and extended to try to quantify these effects. Using the experimental results it is described how HDR images may be displayed so that they are perceptually equivalent under different viewing conditions. A new interpretation of the experimental results is reported, yielding a new, luminance invariant model for the appropriate display "gamma". In this way the consistency of HDR image reproduction should be improved, thereby better maintaining "creative intent" in television.

High dynamic range coding imaging system

NASA Astrophysics Data System (ADS)

Wu, Renfan; Huang, Yifan; Hou, Guangqi

2014-10-01

We present a high dynamic range (HDR) imaging system design scheme based on coded aperture technique. This scheme can help us obtain HDR images which have extended depth of field. We adopt Sparse coding algorithm to design coded patterns. Then we utilize the sensor unit to acquire coded images under different exposure settings. With the guide of the multiple exposure parameters, a series of low dynamic range (LDR) coded images are reconstructed. We use some existing algorithms to fuse and display a HDR image by those LDR images. We build an optical simulation model and get some simulation images to verify the novel system.

Multiple-viewing-zone integral imaging using a dynamic barrier array for three-dimensional displays.

PubMed

Choi, Heejin; Min, Sung-Wook; Jung, Sungyong; Park, Jae-Hyeung; Lee, Byoungho

2003-04-21

In spite of many advantages of integral imaging, the viewing zone in which an observer can see three-dimensional images is limited within a narrow range. Here, we propose a novel method to increase the number of viewing zones by using a dynamic barrier array. We prove our idea by fabricating and locating the dynamic barrier array between a lens array and a display panel. By tilting the barrier array, it is possible to distribute images for each viewing zone. Thus, the number of viewing zones can be increased with an increment of the states of the barrier array tilt.

Evaluation of SMART sensor displays for multidimensional precision control of Space Shuttle remote manipulator

NASA Technical Reports Server (NTRS)

Bejczy, A. K.; Brown, J. W.; Lewis, J. L.

1982-01-01

An enhanced proximity sensor and display system was developed at the Jet Propulsion Laboratory (JPL) and tested on the full scale Space Shuttle Remote Manipulator at the Johnson Space Center (JSC) Manipulator Development Facility (MDF). The sensor system, integrated with a four-claw end effector, measures range error up to 6 inches, and pitch and yaw alignment errors within + or 15 deg., and displays error data on both graphic and numeric displays. The errors are referenced to the end effector control axes through appropriate data processing by a dedicated microcomputer acting on the sensor data in real time. Both display boxes contain a green lamp which indicates whether the combination of range, pitch and yaw errors will assure a successful grapple. More than 200 test runs were completed in early 1980 by three operators at JSC for grasping static and capturing slowly moving targets. The tests have indicated that the use of graphic/numeric displays of proximity sensor information improves precision control of grasp/capture range by more than a factor of two for both static and dynamic grapple conditions.

Far-IR transparency and dynamic infrared signature control with novel conducting polymer systems

NASA Astrophysics Data System (ADS)

Chandrasekhar, Prasanna; Dooley, T. J.

1995-09-01

Materials which possess transparency, coupled with active controllability of this transparency in the infrared (IR), are today an increasingly important requirement, for varied applications. These applications include windows for IR sensors, IR-region flat panel displays used in camouflage as well as in communication and sight through night-vision goggles, coatings with dynamically controllable IR-emissivity, and thermal conservation coatings. Among stringent requirements for these applications are large dynamic ranges (color contrast), 'multi-color' or broad-band characteristics, extended cyclability, long memory retention, matrix addressability, small area fabricability, low power consumption, and environmental stability. Among materials possessing the requirements for variation of IR signature, conducting polymers (CPs) appear to be the only materials with dynamic, actively controllable signature and acceptable dynamic range. Conventional CPs such as poly(alkyl thiophene), poly(pyrrole) or poly(aniline) show very limited dynamic range, especially in the far-IR, while also showing poor transparency. We have developed a number of novel CP systems ('system' implying the CP, the selected dopant, the synthesis method, and the electrolyte) with very wide dynamic range (up to 90% in both important IR regions, 3 - 5 (mu) and 8 - 12 (mu) ), high cyclability (to 105 cycles with less than 10% optical degradation), nearly indefinite optical memory retention, matrix addressability of multi-pixel displays, very wide operating temperature and excellent environmental stability, low charge capacity, and processability into areas from less than 1 mm2 to more than 100 cm2. The criteria used to design and arrive at these CP systems, together with representative IR signature data, are presented in this paper.

Virtual acoustics displays

NASA Technical Reports Server (NTRS)

Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

1991-01-01

The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

Virtual acoustics displays

NASA Astrophysics Data System (ADS)

Wenzel, Elizabeth M.; Fisher, Scott S.; Stone, Philip K.; Foster, Scott H.

1991-03-01

The real time acoustic display capabilities are described which were developed for the Virtual Environment Workstation (VIEW) Project at NASA-Ames. The acoustic display is capable of generating localized acoustic cues in real time over headphones. An auditory symbology, a related collection of representational auditory 'objects' or 'icons', can be designed using ACE (Auditory Cue Editor), which links both discrete and continuously varying acoustic parameters with information or events in the display. During a given display scenario, the symbology can be dynamically coordinated in real time with 3-D visual objects, speech, and gestural displays. The types of displays feasible with the system range from simple warnings and alarms to the acoustic representation of multidimensional data or events.

Real-time high dynamic range laser scanning microscopy

NASA Astrophysics Data System (ADS)

Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.

2016-04-01

In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging.

Fluctuations of global energy release and crackling in nominally brittle heterogeneous fracture.

PubMed

Barés, J; Hattali, M L; Dalmas, D; Bonamy, D

2014-12-31

The temporal evolution of mechanical energy and spatially averaged crack speed are both monitored in slowly fracturing artificial rocks. Both signals display an irregular burstlike dynamics, with power-law distributed fluctuations spanning a broad range of scales. Yet, the elastic power released at each time step is proportional to the global velocity all along the process, which enables defining a material-constant fracture energy. We characterize the intermittent dynamics by computing the burst statistics. This latter displays the scale-free features signature of crackling dynamics, in qualitative but not quantitative agreement with the depinning interface models derived for fracture problems. The possible sources of discrepancies are pointed out and discussed.

Electrophoresis Gel Quantification with a Flatbed Scanner and Versatile Lighting from a Screen Scavenged from a Liquid Crystal Display (LCD) Monitor

ERIC Educational Resources Information Center

Yeung, Brendan; Ng, Tuck Wah; Tan, Han Yen; Liew, Oi Wah

2012-01-01

The use of different types of stains in the quantification of proteins separated on gels using electrophoresis offers the capability of deriving good outcomes in terms of linear dynamic range, sensitivity, and compatibility with specific proteins. An inexpensive, simple, and versatile lighting system based on liquid crystal display backlighting is…

Effect of color on pilot performance and transfer functions using a full-spectrum, calligraphic, color display system

NASA Technical Reports Server (NTRS)

Chase, W. D.

1976-01-01

The use of blue and red color in out-of-window cockpit displays, in full-spectrum calligraphic computer-generated display systems, is studied with attention given to pilot stereographic depth perception and response to visual cues. Displays for vertical approach, with dynamic and frozen-range landing approach and perspective arrays, are analyzed. Pilot transfer function and the transfer function associated with the contrasted approach and perspective arrays are discussed. Out-of-window blue lights are perceived by pilots as indicating greater distance depth, red lights as indicating proximity. The computer-generated chromatic display was adapted to flight simulators for the tests.

High dynamic range adaptive real-time smart camera: an overview of the HDR-ARTiST project

NASA Astrophysics Data System (ADS)

Lapray, Pierre-Jean; Heyrman, Barthélémy; Ginhac, Dominique

2015-04-01

Standard cameras capture only a fraction of the information that is visible to the human visual system. This is specifically true for natural scenes including areas of low and high illumination due to transitions between sunlit and shaded areas. When capturing such a scene, many cameras are unable to store the full Dynamic Range (DR) resulting in low quality video where details are concealed in shadows or washed out by sunlight. The imaging technique that can overcome this problem is called HDR (High Dynamic Range) imaging. This paper describes a complete smart camera built around a standard off-the-shelf LDR (Low Dynamic Range) sensor and a Virtex-6 FPGA board. This smart camera called HDR-ARtiSt (High Dynamic Range Adaptive Real-time Smart camera) is able to produce a real-time HDR live video color stream by recording and combining multiple acquisitions of the same scene while varying the exposure time. This technique appears as one of the most appropriate and cheapest solution to enhance the dynamic range of real-life environments. HDR-ARtiSt embeds real-time multiple captures, HDR processing, data display and transfer of a HDR color video for a full sensor resolution (1280 1024 pixels) at 60 frames per second. The main contributions of this work are: (1) Multiple Exposure Control (MEC) dedicated to the smart image capture with alternating three exposure times that are dynamically evaluated from frame to frame, (2) Multi-streaming Memory Management Unit (MMMU) dedicated to the memory read/write operations of the three parallel video streams, corresponding to the different exposure times, (3) HRD creating by combining the video streams using a specific hardware version of the Devebecs technique, and (4) Global Tone Mapping (GTM) of the HDR scene for display on a standard LCD monitor.

Towards a robust HDR imaging system

NASA Astrophysics Data System (ADS)

Long, Xin; Zeng, Xiangrong; Huangpeng, Qizi; Zhou, Jinglun; Feng, Jing

2016-07-01

High dynamic range (HDR) images can show more details and luminance information in general display device than low dynamic image (LDR) images. We present a robust HDR imaging system which can deal with blurry LDR images, overcoming the limitations of most existing HDR methods. Experiments on real images show the effectiveness and competitiveness of the proposed method.

Real-time high dynamic range laser scanning microscopy

PubMed Central

Vinegoni, C.; Leon Swisher, C.; Fumene Feruglio, P.; Giedt, R. J.; Rousso, D. L.; Stapleton, S.; Weissleder, R.

2016-01-01

In conventional confocal/multiphoton fluorescence microscopy, images are typically acquired under ideal settings and after extensive optimization of parameters for a given structure or feature, often resulting in information loss from other image attributes. To overcome the problem of selective data display, we developed a new method that extends the imaging dynamic range in optical microscopy and improves the signal-to-noise ratio. Here we demonstrate how real-time and sequential high dynamic range microscopy facilitates automated three-dimensional neural segmentation. We address reconstruction and segmentation performance on samples with different size, anatomy and complexity. Finally, in vivo real-time high dynamic range imaging is also demonstrated, making the technique particularly relevant for longitudinal imaging in the presence of physiological motion and/or for quantification of in vivo fast tracer kinetics during functional imaging. PMID:27032979

Autostereoscopic 3D display system with dynamic fusion of the viewing zone under eye tracking: principles, setup, and evaluation [Invited].

PubMed

Yoon, Ki-Hyuk; Kang, Min-Koo; Lee, Hwasun; Kim, Sung-Kyu

2018-01-01

We study optical technologies for viewer-tracked autostereoscopic 3D display (VTA3D), which provides improved 3D image quality and extended viewing range. In particular, we utilize a technique-the so-called dynamic fusion of viewing zone (DFVZ)-for each 3D optical line to realize image quality equivalent to that achievable at optimal viewing distance, even when a viewer is moving in a depth direction. In addition, we examine quantitative properties of viewing zones provided by the VTA3D system that adopted DFVZ, revealing that the optimal viewing zone can be formed at viewer position. Last, we show that the comfort zone is extended due to DFVZ. This is demonstrated by a viewer's subjective evaluation of the 3D display system that employs both multiview autostereoscopic 3D display and DFVZ.

Evaluation of detector dynamic range in the x-ray exposure domain in mammography: a comparison between film-screen and flat panel detector systems.

PubMed

Cooper, Virgil N; Oshiro, Thomas; Cagnon, Christopher H; Bassett, Lawrence W; McLeod-Stockmann, Tyler M; Bezrukiy, Nikita V

2003-10-01

Digital detectors in mammography have wide dynamic range in addition to the benefit of decoupled acquisition and display. How wide the dynamic range is and how it compares to film-screen systems in the clinical x-ray exposure domain are unclear. In this work, we compare the effective dynamic ranges of film-screen and flat panel mammography systems, along with the dynamic ranges of their component image receptors in the clinical x-ray exposure domain. An ACR mammography phantom was imaged using variable mAs (exposure) values for both systems. The dynamic range of the contrast-limited film-screen system was defined as that ratio of mAs (exposure) values for a 26 kVp Mo/Mo (HVL=0.34 mm Al) beam that yielded passing phantom scores. The same approach was done for the noise-limited digital system. Data from three independent observers delineated a useful phantom background optical density range of 1.27 to 2.63, which corresponded to a dynamic range of 2.3 +/- 0.53. The digital system had a dynamic range of 9.9 +/- 1.8, which was wider than the film-screen system (p<0.02). The dynamic range of the film-screen system was limited by the dynamic range of the film. The digital detector, on the other hand, had an estimated dynamic range of 42, which was wider than the dynamic range of the digital system in its entirety by a factor of 4. The generator/tube combination was the limiting factor in determining the digital system's dynamic range.

A variable-collimation display system

NASA Astrophysics Data System (ADS)

Batchko, Robert; Robinson, Sam; Schmidt, Jack; Graniela, Benito

2014-03-01

Two important human depth cues are accommodation and vergence. Normally, the eyes accommodate and converge or diverge in tandem; changes in viewing distance cause the eyes to simultaneously adjust both focus and orientation. However, ambiguity between accommodation and vergence cues is a well-known limitation in many stereoscopic display technologies. This limitation also arises in state-of-the-art full-flight simulator displays. In current full-flight simulators, the out-the-window (OTW) display (i.e., the front cockpit window display) employs a fixed collimated display technology which allows the pilot and copilot to perceive the OTW training scene without angular errors or distortions; however, accommodation and vergence cues are limited to fixed ranges (e.g., ~ 20 m). While this approach works well for long-range, the ambiguity of depth cues at shorter range hinders the pilot's ability to gauge distances in critical maneuvers such as vertical take-off and landing (VTOL). This is the first in a series of papers on a novel, variable-collimation display (VCD) technology that is being developed under NAVY SBIR Topic N121-041 funding. The proposed VCD will integrate with rotary-wing and vertical take-off and landing simulators and provide accurate accommodation and vergence cues for distances ranging from approximately 3 m outside the chin window to ~ 20 m. A display that offers dynamic accommodation and vergence could improve pilot safety and training, and impact other applications presently limited by lack of these depth cues.

Event-Based Tone Mapping for Asynchronous Time-Based Image Sensor

PubMed Central

Simon Chane, Camille; Ieng, Sio-Hoi; Posch, Christoph; Benosman, Ryad B.

2016-01-01

The asynchronous time-based neuromorphic image sensor ATIS is an array of autonomously operating pixels able to encode luminance information with an exceptionally high dynamic range (>143 dB). This paper introduces an event-based methodology to display data from this type of event-based imagers, taking into account the large dynamic range and high temporal accuracy that go beyond available mainstream display technologies. We introduce an event-based tone mapping methodology for asynchronously acquired time encoded gray-level data. A global and a local tone mapping operator are proposed. Both are designed to operate on a stream of incoming events rather than on time frame windows. Experimental results on real outdoor scenes are presented to evaluate the performance of the tone mapping operators in terms of quality, temporal stability, adaptation capability, and computational time. PMID:27642275

Context-dependent JPEG backward-compatible high-dynamic range image compression

NASA Astrophysics Data System (ADS)

Korshunov, Pavel; Ebrahimi, Touradj

2013-10-01

High-dynamic range (HDR) imaging is expected, together with ultrahigh definition and high-frame rate video, to become a technology that may change photo, TV, and film industries. Many cameras and displays capable of capturing and rendering both HDR images and video are already available in the market. The popularity and full-public adoption of HDR content is, however, hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of low-dynamic range (LDR) displays that are unable to render HDR. To facilitate the wide spread of HDR usage, the backward compatibility of HDR with commonly used legacy technologies for storage, rendering, and compression of video and images are necessary. Although many tone-mapping algorithms are developed for generating viewable LDR content from HDR, there is no consensus of which algorithm to use and under which conditions. We, via a series of subjective evaluations, demonstrate the dependency of the perceptual quality of the tone-mapped LDR images on the context: environmental factors, display parameters, and image content itself. Based on the results of subjective tests, it proposes to extend JPEG file format, the most popular image format, in a backward compatible manner to deal with HDR images also. An architecture to achieve such backward compatibility with JPEG is proposed. A simple implementation of lossy compression demonstrates the efficiency of the proposed architecture compared with the state-of-the-art HDR image compression.

Biomechanics of the Peacock’s Display: How Feather Structure and Resonance Influence Multimodal Signaling

PubMed Central

Dakin, Roslyn; McCrossan, Owen; Hare, James F.; Montgomerie, Robert; Amador Kane, Suzanne

2016-01-01

Courtship displays may serve as signals of the quality of motor performance, but little is known about the underlying biomechanics that determines both their signal content and costs. Peacocks (Pavo cristatus) perform a complex, multimodal “train-rattling” display in which they court females by vibrating the iridescent feathers in their elaborate train ornament. Here we study how feather biomechanics influences the performance of this display using a combination of field recordings and laboratory experiments. Using high-speed video, we find that train-rattling peacocks stridulate their tail feathers against the train at 25.6 Hz, on average, generating a broadband, pulsating mechanical sound at that frequency. Laboratory measurements demonstrate that arrays of peacock tail and train feathers have a broad resonant peak in their vibrational spectra at the range of frequencies used for train-rattling during the display, and the motion of feathers is just as expected for feathers shaking near resonance. This indicates that peacocks are able to drive feather vibrations energetically efficiently over a relatively broad range of frequencies, enabling them to modulate the feather vibration frequency of their displays. Using our field data, we show that peacocks with longer trains use slightly higher vibration frequencies on average, even though longer train feathers are heavier and have lower resonant frequencies. Based on these results, we propose hypotheses for future studies of the function and energetics of this display that ask why its dynamic elements might attract and maintain female attention. Finally, we demonstrate how the mechanical structure of the train feathers affects the peacock’s visual display by allowing the colorful iridescent eyespots–which strongly influence female mate choice–to remain nearly stationary against a dynamic iridescent background. PMID:27119380

Biomechanics of the Peacock's Display: How Feather Structure and Resonance Influence Multimodal Signaling.

PubMed

Dakin, Roslyn; McCrossan, Owen; Hare, James F; Montgomerie, Robert; Amador Kane, Suzanne

2016-01-01

Courtship displays may serve as signals of the quality of motor performance, but little is known about the underlying biomechanics that determines both their signal content and costs. Peacocks (Pavo cristatus) perform a complex, multimodal "train-rattling" display in which they court females by vibrating the iridescent feathers in their elaborate train ornament. Here we study how feather biomechanics influences the performance of this display using a combination of field recordings and laboratory experiments. Using high-speed video, we find that train-rattling peacocks stridulate their tail feathers against the train at 25.6 Hz, on average, generating a broadband, pulsating mechanical sound at that frequency. Laboratory measurements demonstrate that arrays of peacock tail and train feathers have a broad resonant peak in their vibrational spectra at the range of frequencies used for train-rattling during the display, and the motion of feathers is just as expected for feathers shaking near resonance. This indicates that peacocks are able to drive feather vibrations energetically efficiently over a relatively broad range of frequencies, enabling them to modulate the feather vibration frequency of their displays. Using our field data, we show that peacocks with longer trains use slightly higher vibration frequencies on average, even though longer train feathers are heavier and have lower resonant frequencies. Based on these results, we propose hypotheses for future studies of the function and energetics of this display that ask why its dynamic elements might attract and maintain female attention. Finally, we demonstrate how the mechanical structure of the train feathers affects the peacock's visual display by allowing the colorful iridescent eyespots-which strongly influence female mate choice-to remain nearly stationary against a dynamic iridescent background.

High Dynamic Range Imaging Using Multiple Exposures

NASA Astrophysics Data System (ADS)

Hou, Xinglin; Luo, Haibo; Zhou, Peipei; Zhou, Wei

2017-06-01

It is challenging to capture a high-dynamic range (HDR) scene using a low-dynamic range (LDR) camera. This paper presents an approach for improving the dynamic range of cameras by using multiple exposure images of same scene taken under different exposure times. First, the camera response function (CRF) is recovered by solving a high-order polynomial in which only the ratios of the exposures are used. Then, the HDR radiance image is reconstructed by weighted summation of the each radiance maps. After that, a novel local tone mapping (TM) operator is proposed for the display of the HDR radiance image. By solving the high-order polynomial, the CRF can be recovered quickly and easily. Taken the local image feature and characteristic of histogram statics into consideration, the proposed TM operator could preserve the local details efficiently. Experimental result demonstrates the effectiveness of our method. By comparison, the method outperforms other methods in terms of imaging quality.

Review of fluorescence guided surgery visualization and overlay techniques

PubMed Central

Elliott, Jonathan T.; Dsouza, Alisha V.; Davis, Scott C.; Olson, Jonathan D.; Paulsen, Keith D.; Roberts, David W.; Pogue, Brian W.

2015-01-01

In fluorescence guided surgery, data visualization represents a critical step between signal capture and display needed for clinical decisions informed by that signal. The diversity of methods for displaying surgical images are reviewed, and a particular focus is placed on electronically detected and visualized signals, as required for near-infrared or low concentration tracers. Factors driving the choices such as human perception, the need for rapid decision making in a surgical environment, and biases induced by display choices are outlined. Five practical suggestions are outlined for optimal display orientation, color map, transparency/alpha function, dynamic range compression, and color perception check. PMID:26504628

Epidemic Dynamics in Open Quantum Spin Systems

NASA Astrophysics Data System (ADS)

Pérez-Espigares, Carlos; Marcuzzi, Matteo; Gutiérrez, Ricardo; Lesanovsky, Igor

2017-10-01

We explore the nonequilibrium evolution and stationary states of an open many-body system that displays epidemic spreading dynamics in a classical and a quantum regime. Our study is motivated by recent experiments conducted in strongly interacting gases of highly excited Rydberg atoms where the facilitated excitation of Rydberg states competes with radiative decay. These systems approximately implement open quantum versions of models for population dynamics or disease spreading where species can be in a healthy, infected or immune state. We show that in a two-dimensional lattice, depending on the dominance of either classical or quantum effects, the system may display a different kind of nonequilibrium phase transition. We moreover discuss the observability of our findings in laser driven Rydberg gases with particular focus on the role of long-range interactions.

Role of five-fold symmetry in undercooled Al-Cu binary alloys

NASA Astrophysics Data System (ADS)

Pasturel, A.; Jakse, N.

2018-04-01

We investigate the role of five-fold symmetry (FFS) in undercooled Al1-xCux liquids (x = 0.3 and 0.4) using ab initio molecular dynamics simulations. We show that the structure factors and pair-correlation functions display characteristic features which are compatible with the occurrence of FFS and the emergence of a medium range order (MRO) below a temperature TX located close to the liquidus temperature. Then, we demonstrate that the formation of MRO is associated with a strong increase in local FFS-motifs which become more and more connected with decreasing temperature. From the temperature dependence of dynamic properties, we find that TX corresponds also to the onset of dynamic phenomena, like the non-Arrhenius temperature dependence of transport properties and the emergence of dynamical heterogeneities (DHs). Finally, we clearly identify a relationship between the fivefold topology at the medium-range scale (IMRO) and the spatial distribution of DHs using isoconfigurational ensemble simulations. This questions the direct role of the connectivity of five-fold-based motifs found in IMRO in nucleation of the parent crystalline ground states, namely, Al2Cu and Al3Cu2, which also display local ordering with a significant degree of FFS.

Effect of tone mapping operators on visual attention deployment

NASA Astrophysics Data System (ADS)

Narwaria, Manish; Perreira Da Silva, Matthieu; Le Callet, Patrick; Pepion, Romuald

2012-10-01

High Dynamic Range (HDR) images/videos require the use of a tone mapping operator (TMO) when visualized on Low Dynamic Range (LDR) displays. From an artistic intention point of view, TMOs are not necessarily transparent and might induce different behavior to view the content. In this paper, we investigate and quantify how TMOs modify visual attention (VA). To that end both objective and subjective tests in the form of eye-tracking experiments have been conducted on several still image content that have been processed by 11 different TMOs. Our studies confirm that TMOs can indeed modify human attention and fixation behavior significantly. Therefore our studies suggest that VA needs consideration for evaluating the overall perceptual impact of TMOs on HDR content. Since the existing studies so far have only considered the quality or aesthetic appeal angle, this study brings in a new perspective regarding the importance of VA in HDR content processing for visualization on LDR displays.

Dynamic and static fatigue behavior of sintered silicon nitrides

NASA Technical Reports Server (NTRS)

Chang, J.; Khandelwal, P.; Heitman, P. W.

1987-01-01

The dynamic and static fatigue behavior of Kyocera SN220M sintered silicon nitride at 1000 C was studied. Fractographic analysis of the material failing in dynamic fatigue revealed the presence of slow crack growth (SCG) at stressing rates below 41 MPa/min. Under conditions of static fatigue this material also displayed SCG at stresses below 345 MPa. SCG appears to be controlled by microcracking of the grain boundaries. The crack velocity exponent (n) determined from both dynamic and static fatigue tests ranged from 11 to 16.

Enhanced visual perception through tone mapping

NASA Astrophysics Data System (ADS)

Harrison, Andre; Mullins, Linda L.; Raglin, Adrienne; Etienne-Cummings, Ralph

2016-05-01

Tone mapping operators compress high dynamic range images to improve the picture quality on a digital display when the dynamic range of the display is lower than that of the image. However, tone mapping operators have been largely designed and evaluated based on the aesthetic quality of the resulting displayed image or how perceptually similar the compressed image appears relative to the original scene. They also often require per image tuning of parameters depending on the content of the image. In military operations, however, the amount of information that can be perceived is more important than the aesthetic quality of the image and any parameter adjustment needs to be as automated as possible regardless of the content of the image. We have conducted two studies to evaluate the perceivable detail of a set of tone mapping algorithms, and we apply our findings to develop and test an automated tone mapping algorithm that demonstrates a consistent improvement in the amount of perceived detail. An automated, and thereby predictable, tone mapping method enables a consistent presentation of perceivable features, can reduce the bandwidth required to transmit the imagery, and can improve the accessibility of the data by reducing the needed expertise of the analyst(s) viewing the imagery.

Fast exposure time decision in multi-exposure HDR imaging

NASA Astrophysics Data System (ADS)

Piao, Yongjie; Jin, Guang

2012-10-01

Currently available imaging and display system exists the problem of insufficient dynamic range, and the system cannot restore all the information for an high dynamic range (HDR) scene. The number of low dynamic range(LDR) image samples and fastness of exposure time decision impacts the real-time performance of the system dramatically. In order to realize a real-time HDR video acquisition system, this paper proposed a fast and robust method for exposure time selection in under and over exposure area which is based on system response function. The method utilized the monotony of the imaging system. According to this characteristic the exposure time is adjusted to an initial value to make the median value of the image equals to the middle value of the system output range; then adjust the exposure time to make the pixel value on two sides of histogram be the middle value of the system output range. Thus three low dynamic range images are acquired. Experiments show that the proposed method for adjusting the initial exposure time can converge in two iterations which is more fast and stable than average gray control method. As to the exposure time adjusting in under and over exposed area, the proposed method can use the dynamic range of the system more efficiently than fixed exposure time method.

Evaluation of color encodings for high dynamic range pixels

NASA Astrophysics Data System (ADS)

Boitard, Ronan; Mantiuk, Rafal K.; Pouli, Tania

2015-03-01

Traditional Low Dynamic Range (LDR) color spaces encode a small fraction of the visible color gamut, which does not encompass the range of colors produced on upcoming High Dynamic Range (HDR) displays. Future imaging systems will require encoding much wider color gamut and luminance range. Such wide color gamut can be represented using floating point HDR pixel values but those are inefficient to encode. They also lack perceptual uniformity of the luminance and color distribution, which is provided (in approximation) by most LDR color spaces. Therefore, there is a need to devise an efficient, perceptually uniform and integer valued representation for high dynamic range pixel values. In this paper we evaluate several methods for encoding colour HDR pixel values, in particular for use in image and video compression. Unlike other studies we test both luminance and color difference encoding in a rigorous 4AFC threshold experiments to determine the minimum bit-depth required. Results show that the Perceptual Quantizer (PQ) encoding provides the best perceptual uniformity in the considered luminance range, however the gain in bit-depth is rather modest. More significant difference can be observed between color difference encoding schemes, from which YDuDv encoding seems to be the most efficient.

Design of the control system for full-color LED display based on MSP430 MCU

NASA Astrophysics Data System (ADS)

Li, Xue; Xu, Hui-juan; Qin, Ling-ling; Zheng, Long-jiang

2013-08-01

The LED display incorporate the micro electronic technique, computer technology and information processing as a whole, it becomes the most preponderant of a new generation of display media with the advantages of bright in color, high dynamic range, high brightness and long operating life, etc. The LED display has been widely used in the bank, securities trading, highway signs, airport and advertising, etc. According to the display color, the LED display screen is divided into monochrome screen, double color display and full color display. With the diversification of the LED display's color and the ceaseless rise of the display demands, the LED display's drive circuit and control technology also get the corresponding progress and development. The earliest monochrome screen just displaying Chinese characters, simple character or digital, so the requirements of the controller are relatively low. With the widely used of the double color LED display, the performance of its controller will also increase. In recent years, the full color LED display with three primary colors of red, green, blue and grayscale display effect has been highly attention with its rich and colorful display effect. Every true color pixel includes three son pixels of red, green, blue, using the space colour mixture to realize the multicolor. The dynamic scanning control system of LED full-color display is designed based on MSP430 microcontroller technology of the low power consumption. The gray control technology of this system used the new method of pulse width modulation (PWM) and 19 games show principle are combining. This method in meet 256 level grayscale display conditions, improves the efficiency of the LED light device, and enhances the administrative levels feels of the image. Drive circuit used 1/8 scanning constant current drive mode, and make full use of the single chip microcomputer I/O mouth resources to complete the control. The system supports text, pictures display of 256 grayscale full-color LED screen.

Image gathering and digital restoration for fidelity and visual quality

NASA Technical Reports Server (NTRS)

Huck, Friedrich O.; Alter-Gartenberg, Rachel; Rahman, Zia-Ur

1991-01-01

The fidelity and resolution of the traditional Wiener restorations given in the prevalent digital processing literature can be significantly improved when the transformations between the continuous and discrete representations in image gathering and display are accounted for. However, the visual quality of these improved restorations also is more sensitive to the defects caused by aliasing artifacts, colored noise, and ringing near sharp edges. In this paper, these visual defects are characterized, and methods for suppressing them are presented. It is demonstrated how the visual quality of fidelity-maximized images can be improved when (1) the image-gathering system is specifically designed to enhance the performance of the image-restoration algorithm, and (2) the Wiener filter is combined with interactive Gaussian smoothing, synthetic high edge enhancement, and nonlinear tone-scale transformation. The nonlinear transformation is used primarily to enhance the spatial details that are often obscurred when the normally wide dynamic range of natural radiance fields is compressed into the relatively narrow dynamic range of film and other displays.

Evaluation of a HDR image sensor with logarithmic response for mobile video-based applications

NASA Astrophysics Data System (ADS)

Tektonidis, Marco; Pietrzak, Mateusz; Monnin, David

2017-10-01

The performance of mobile video-based applications using conventional LDR (Low Dynamic Range) image sensors highly depends on the illumination conditions. As an alternative, HDR (High Dynamic Range) image sensors with logarithmic response are capable to acquire illumination-invariant HDR images in a single shot. We have implemented a complete image processing framework for a HDR sensor, including preprocessing methods (nonuniformity correction (NUC), cross-talk correction (CTC), and demosaicing) as well as tone mapping (TM). We have evaluated the HDR sensor for video-based applications w.r.t. the display of images and w.r.t. image analysis techniques. Regarding the display we have investigated the image intensity statistics over time, and regarding image analysis we assessed the number of feature correspondences between consecutive frames of temporal image sequences. For the evaluation we used HDR image data recorded from a vehicle on outdoor or combined outdoor/indoor itineraries, and we performed a comparison with corresponding conventional LDR image data.

Long-range interactions, wobbles, and phase defects in chains of model cilia

NASA Astrophysics Data System (ADS)

Brumley, Douglas R.; Bruot, Nicolas; Kotar, Jurij; Goldstein, Raymond E.; Cicuta, Pietro; Polin, Marco

2016-12-01

Eukaryotic cilia and flagella are chemo-mechanical oscillators capable of generating long-range coordinated motions known as metachronal waves. Pair synchronization is a fundamental requirement for these collective dynamics, but it is generally not sufficient for collective phase-locking, chiefly due to the effect of long-range interactions. Here we explore experimentally and numerically a minimal model for a ciliated surface: hydrodynamically coupled oscillators rotating above a no-slip plane. Increasing their distance from the wall profoundly affects the global dynamics, due to variations in hydrodynamic interaction range. The array undergoes a transition from a traveling wave to either a steady chevron pattern or one punctuated by periodic phase defects. Within the transition between these regimes the system displays behavior reminiscent of chimera states.

Backwards compatible high dynamic range video compression

NASA Astrophysics Data System (ADS)

Dolzhenko, Vladimir; Chesnokov, Vyacheslav; Edirisinghe, Eran A.

2014-02-01

This paper presents a two layer CODEC architecture for high dynamic range video compression. The base layer contains the tone mapped video stream encoded with 8 bits per component which can be decoded using conventional equipment. The base layer content is optimized for rendering on low dynamic range displays. The enhancement layer contains the image difference, in perceptually uniform color space, between the result of inverse tone mapped base layer content and the original video stream. Prediction of the high dynamic range content reduces the redundancy in the transmitted data while still preserves highlights and out-of-gamut colors. Perceptually uniform colorspace enables using standard ratedistortion optimization algorithms. We present techniques for efficient implementation and encoding of non-uniform tone mapping operators with low overhead in terms of bitstream size and number of operations. The transform representation is based on human vision system model and suitable for global and local tone mapping operators. The compression techniques include predicting the transform parameters from previously decoded frames and from already decoded data for current frame. Different video compression techniques are compared: backwards compatible and non-backwards compatible using AVC and HEVC codecs.

Gamut mapping in a high-dynamic-range color space

NASA Astrophysics Data System (ADS)

Preiss, Jens; Fairchild, Mark D.; Ferwerda, James A.; Urban, Philipp

2014-01-01

In this paper, we present a novel approach of tone mapping as gamut mapping in a high-dynamic-range (HDR) color space. High- and low-dynamic-range (LDR) images as well as device gamut boundaries can simultaneously be represented within such a color space. This enables a unified transformation of the HDR image into the gamut of an output device (in this paper called HDR gamut mapping). An additional aim of this paper is to investigate the suitability of a specific HDR color space to serve as a working color space for the proposed HDR gamut mapping. For the HDR gamut mapping, we use a recent approach that iteratively minimizes an image-difference metric subject to in-gamut images. A psychophysical experiment on an HDR display shows that the standard reproduction workflow of two subsequent transformations - tone mapping and then gamut mapping - may be improved by HDR gamut mapping.

Introducing a Public Stereoscopic 3D High Dynamic Range (SHDR) Video Database

NASA Astrophysics Data System (ADS)

Banitalebi-Dehkordi, Amin

2017-03-01

High dynamic range (HDR) displays and cameras are paving their ways through the consumer market at a rapid growth rate. Thanks to TV and camera manufacturers, HDR systems are now becoming available commercially to end users. This is taking place only a few years after the blooming of 3D video technologies. MPEG/ITU are also actively working towards the standardization of these technologies. However, preliminary research efforts in these video technologies are hammered by the lack of sufficient experimental data. In this paper, we introduce a Stereoscopic 3D HDR database of videos that is made publicly available to the research community. We explain the procedure taken to capture, calibrate, and post-process the videos. In addition, we provide insights on potential use-cases, challenges, and research opportunities, implied by the combination of higher dynamic range of the HDR aspect, and depth impression of the 3D aspect.

Co-evolution of payoff strategy and interaction strategy in prisoner's dilemma game

NASA Astrophysics Data System (ADS)

Zhang, Kangjie; Cheng, Hongyan

2016-11-01

Co-evolutionary dynamical models, providing a realistic paradigm for investigating complex system, have been extensively studied. In this paper, the co-evolution of payoff strategy and interaction strategy is studied. Starting with an initial Gaussian distribution of payoff strategy r with the mean u and the variance q, we focus on the final distribution of the payoff strategy. We find that final distribution of the payoff strategy may display different structures depending on parameters. In the ranges u < - 1 and u > 3, the distribution displays a single-peak structure which is symmetric about r = u. The distribution manifests itself as a double-peak structure in the range - 1 < u < 3 although a fake three-peak structure shows up in range 1 < u < 2. The explanations on the formation of different types of payoff strategy distributions are presented.

Monitoring dynamic loads on wind tunnel force balances

NASA Technical Reports Server (NTRS)

Ferris, Alice T.; White, William C.

1989-01-01

Two devices have been developed at NASA Langley to monitor the dynamic loads incurred during wind-tunnel testing. The Balance Dynamic Display Unit (BDDU), displays and monitors the combined static and dynamic forces and moments in the orthogonal axes. The Balance Critical Point Analyzer scales and sums each normalized signal from the BDDU to obtain combined dynamic and static signals that represent the dynamic loads at predefined high-stress points. The display of each instrument is a multiplex of six analog signals in a way that each channel is displayed sequentially as one-sixth of the horizontal axis on a single oscilloscope trace. Thus this display format permits the operator to quickly and easily monitor the combined static and dynamic level of up to six channels at the same time.

Scaling theory of temporal correlations and size-dependent fluctuations in the traded value of stocks

NASA Astrophysics Data System (ADS)

Eisler, Zoltán; Kertész, János

2006-04-01

Records of the traded value fi of stocks display fluctuation scaling, a proportionality between the standard deviation σi and the average ⟨fi⟩ : σi∝⟨fi⟩α , with a strong time scale dependence α(Δt) . The nontrivial (i.e., neither 0.5 nor 1) value of α may have different origins and provides information about the microscopic dynamics. We present a set of stylized facts and then show their connection to such behavior. The functional form α(Δt) originates from two aspects of the dynamics: Stocks of larger companies both tend to be traded in larger packages and also display stronger correlations of traded value. The results are integrated into a general framework that can be applied to a wide range of complex systems.

Design and testing of artifact-suppressed adaptive histogram equalization: a contrast-enhancement technique for display of digital chest radiographs.

PubMed

Rehm, K; Seeley, G W; Dallas, W J; Ovitt, T W; Seeger, J F

1990-01-01

One of the goals of our research in the field of digital radiography has been to develop contrast-enhancement algorithms for eventual use in the display of chest images on video devices with the aim of preserving the diagnostic information presently available with film, some of which would normally be lost because of the smaller dynamic range of video monitors. The ASAHE algorithm discussed in this article has been tested by investigating observer performance in a difficult detection task involving phantoms and simulated lung nodules, using film as the output medium. The results of the experiment showed that the algorithm is successful in providing contrast-enhanced, natural-looking chest images while maintaining diagnostic information. The algorithm did not effect an increase in nodule detectability, but this was not unexpected because film is a medium capable of displaying a wide range of gray levels. It is sufficient at this stage to show that there is no degradation in observer performance. Future tests will evaluate the performance of the ASAHE algorithm in preparing chest images for video display.

Force-Balance Dynamic Display

NASA Technical Reports Server (NTRS)

Ferris, Alice T.; White, William C.

1988-01-01

Balance dynamic display unit (BDDU) is compact system conditioning six dynamic analog signals so they are monitored simultaneously in real time on single-trace oscilloscope. Typical BDDU oscilloscope display in scan mode shows each channel occupying one-sixth of total trace. System features two display modes usable with conventional, single-channel oscilloscope: multiplexed six-channel "bar-graph" format and single-channel display. Two-stage visual and audible limit alarm provided for each channel.

Understanding balance differences in individuals with multiple sclerosis with mild disability: An investigation of differences in sensory feedback on postural and dynamic balance control

NASA Astrophysics Data System (ADS)

Denomme, Luke T.

Multiple sclerosis (MS) is an autoimmune disease that affects the central nervous system (CNS) and causes a broad range of neurological symptoms. One of the most common symptoms experienced by individuals with MS is poor balance control during standing and walking. The main mechanism underlying impaired balance control in MS appears to result from slowed somatosensory conduction and impaired central integration. The current thesis assessed postural and dynamic control of balance of 'individuals with MS with mild disability' (IwMS). IwMS were compared to 'healthy age-matched individuals' (HAMI) and community-dwelling 'older adults' (OA). The purpose of this thesis was to quantify differences in postural and dynamic control of balance in IwMS to the two populations who display balance control differences across the lifespan and represent two extreme ends of the balance control continuum due to natural aging. IwMS (n = 12, x¯age: 44 +/- 9.4 years), HAMI (n = 12, x¯age: 45 +/- 9.9 years) and community-dwelling OA (n = 12, x¯ age: 68.1 +/- 4.5 years) postural and dynamic balance control were evaluated during a Romberg task as well as a dynamic steering task. The Romberg task required participants to stand with their feet together and hands by their sides for 45 seconds with either their eyes open or closed. The dynamic steering task required participants to walk and change direction along the M-L plane towards a visual goal. Results from these two tasks reveal that IwMS display differences in postural control when compared to HAMI when vision was removed as well as differences in dynamic stability margin during steering situations. During the postural control task IwMS displayed faster A-P and M-L COP velocities when vision was removed and their COP position was closer to their self-selected maximum stability limits compared to HAMI. Assessment of dynamic stability during the steering task revealed that IwMS displayed reduced walking speed and cadence during the straight walking portion of the task in addition to a smaller DSM range (i.e., COM remained close to lateral BOS) during the entire steering task. These results suggest that IwMS adopt postural and dynamic control strategies (i.e., increased COP velocity, smaller self-selected maximal sway comfort zones and reduced walking speed) in order to maintain stability and complete the tasks. Results further revealed that IwMS display similar levels of postural and dynamic stability to OA despite differences in the type of sensory impairment possessed by each group. The findings also provide insights into the comparison of IwMS to two populations who represent the two extreme ends of the balance control continuum: HAMI and OA. Our data indicates that the level of postural and dynamic balance control in IwMS appears to express similar characteristics and may be located closer to the OA population on this continuum. Future research should evaluate the level of somatosensory impairment (i.e., monofilament testing and tuning fork tendon tap testing) between IwMS and OA in order to better differentiate levels of postural and dynamic balance control between groups and to gain a better understanding of where each group may be specifically located on the age-related balance control continuum.

Augmenting digital displays with computation

NASA Astrophysics Data System (ADS)

Liu, Jing

As we inevitably step deeper and deeper into a world connected via the Internet, more and more information will be exchanged digitally. Displays are the interface between digital information and each individual. Naturally, one fundamental goal of displays is to reproduce information as realistically as possible since humans still care a lot about what happens in the real world. Human eyes are the receiving end of such information exchange; therefore it is impossible to study displays without studying the human visual system. In fact, the design of displays is rather closely coupled with what human eyes are capable of perceiving. For example, we are less interested in building displays that emit light in the invisible spectrum. This dissertation explores how we can augment displays with computation, which takes both display hardware and the human visual system into consideration. Four novel projects on display technologies are included in this dissertation: First, we propose a software-based approach to driving multiview autostereoscopic displays. Our display algorithm can dynamically assign views to hardware display zones based on multiple observers' current head positions, substantially reducing crosstalk and stereo inversion. Second, we present a dense projector array that creates a seamless 3D viewing experience for multiple viewers. We smoothly interpolate the set of viewer heights and distances on a per-vertex basis across the arrays field of view, reducing image distortion, crosstalk, and artifacts from tracking errors. Third, we propose a method for high dynamic range display calibration that takes into account the variation of the chrominance error over luminance. We propose a data structure for enabling efficient representation and querying of the calibration function, which also allows user-guided balancing between memory consumption and the amount of computation. Fourth, we present user studies that demonstrate that the ˜ 60 Hz critical flicker fusion rate for traditional displays is not enough for some computational displays that show complex image patterns. The study focuses on displays with hidden channels, and their application to 3D+2D TV. By taking advantage of the fast growing power of computation and sensors, these four novel display setups - in combination with display algorithms - advance the frontier of computational display research.

HEVC for high dynamic range services

NASA Astrophysics Data System (ADS)

Kim, Seung-Hwan; Zhao, Jie; Misra, Kiran; Segall, Andrew

2015-09-01

Displays capable of showing a greater range of luminance values can render content containing high dynamic range information in a way such that the viewers have a more immersive experience. This paper introduces the design aspects of a high dynamic range (HDR) system, and examines the performance of the HDR processing chain in terms of compression efficiency. Specifically it examines the relation between recently introduced Society of Motion Picture and Television Engineers (SMPTE) ST 2084 transfer function and the High Efficiency Video Coding (HEVC) standard. SMPTE ST 2084 is designed to cover the full range of an HDR signal from 0 to 10,000 nits, however in many situations the valid signal range of actual video might be smaller than SMPTE ST 2084 supported range. The above restricted signal range results in restricted range of code values for input video data and adversely impacts compression efficiency. In this paper, we propose a code value remapping method that extends the restricted range code values into the full range code values so that the existing standards such as HEVC may better compress the video content. The paper also identifies related non-normative encoder-only changes that are required for remapping method for a fair comparison with anchor. Results are presented comparing the efficiency of the current approach versus the proposed remapping method for HM-16.2.

Strategies used by individuals with multiple sclerosis and with mild disability to maintain dynamic stability during a steering task.

PubMed

Denommé, Luke T; Mandalfino, Patricia; Cinelli, Michael E

2014-06-01

Changing direction during walking is a common task humans encounter every day. This destabilizing event requires the central nervous system (CNS) to quickly produce an appropriate response, maintain stability, and propel the body in the intended direction. Previous research has demonstrated that 'individuals with multiple sclerosis' (IwMS) with mild balance impairment display differences in gait characteristics during clinical tests compared with controls. The current study used dynamic stability margin [DSM, difference between COM (i.e. the weighted average of the central point of an individual's total body mass) and lateral BOS (i.e. the most lateral border of the foot that is in contact with the ground)] calculations in addition to gait kinematics to determine whether dynamic stability differences during a steering task were present between IwMS with mild balance impairment and 'healthy age-matched individuals' (HAMI) as well as between IwMS with mild balance impairment and 'community-dwelling older adults' (OA). All IwMS reported mild balance impairment with expanded disability status scale scores ranging between 1.0 and 3.0. The steering task required participants to walk 3 m towards a pressure sensitive trigger mat that would illuminate one of five lights to indicate the future direction of travel (i.e. straight, 45° or 60° to the left or right of the midline). Results revealed that IwMS displayed reduced walking speed and cadence during the approach phase in addition to a smaller DSM range (i.e. COM remained close to lateral BOS) during the entire steering task when compared with HAMI. However, when compared to OAs, IwMS did not display differences in any of the gait kinematics or DSM calculations. Findings suggest that the IwMS displayed a conservative gait strategy in order to maintain stability during the steering task. Lack of dynamic stability differences between IwMS and OAs indicate that both groups use similar strategies to adapt locomotion as a result of impaired somatosensory quality and/or processing.

Pseudo-color coding method for high-dynamic single-polarization SAR images

NASA Astrophysics Data System (ADS)

Feng, Zicheng; Liu, Xiaolin; Pei, Bingzhi

2018-04-01

A raw synthetic aperture radar (SAR) image usually has a 16-bit or higher bit depth, which cannot be directly visualized on 8-bit displays. In this study, we propose a pseudo-color coding method for high-dynamic singlepolarization SAR images. The method considers the characteristics of both SAR images and human perception. In HSI (hue, saturation and intensity) color space, the method carries out high-dynamic range tone mapping and pseudo-color processing simultaneously in order to avoid loss of details and to improve object identifiability. It is a highly efficient global algorithm.

Phase transitions and dynamics of bulk and interfacial water.

PubMed

Franzese, G; Hernando-Martínez, A; Kumar, P; Mazza, M G; Stokely, K; Strekalova, E G; de los Santos, F; Stanley, H E

2010-07-21

New experiments on water at the surface of proteins at very low temperature display intriguing dynamic behaviors. The extreme conditions of these experiments make it difficult to explore the wide range of thermodynamic state points needed to offer a suitable interpretation. Detailed simulations suffer from the same problem, where equilibration times at low temperature become extremely long. We show how Monte Carlo simulations and mean field calculations using a tractable model of water help interpret the experimental results. Here we summarize the results for bulk water and investigate the thermodynamic and dynamic properties of supercooled water at an interface.

Maneuvering in the Complex Path from Genotype to Phenotype

NASA Astrophysics Data System (ADS)

Strohman, Richard

2002-04-01

Human disease phenotypes are controlled not only by genes but by lawful self-organizing networks that display system-wide dynamics. These networks range from metabolic pathways to signaling pathways that regulate hormone action. When perturbed, networks alter their output of matter and energy which, depending on the environmental context, can produce either a pathological or a normal phenotype. Study of the dynamics of these networks by approaches such as metabolic control analysis may provide new insights into the pathogenesis and treatment of complex diseases.

Structure and dynamics of propylammonium nitrate-acetonitrile mixtures: An intricate multi-scale system probed with experimental and theoretical techniques.

PubMed

Campetella, Marco; Mariani, Alessandro; Sadun, Claudia; Wu, Boning; Castner, Edward W; Gontrani, Lorenzo

2018-04-07

In this article, we report the study of structural and dynamical properties for a series of acetonitrile/propylammonium nitrate mixtures as a function of their composition. These systems display an unusual increase in intensity in their X-ray diffraction patterns in the low-q regime, and their 1 H-NMR diffusion-ordered NMR spectroscopy (DOSY) spectra display unusual diffusivities. However, the magnitude of both phenomena for mixtures of propylammonium nitrate is smaller than those observed for ethylammonium nitrate mixtures with the same cosolvent, suggesting that the cation alkyl tail plays an important role in these observations. The experimental X-ray scattering data are compared with the results of molecular dynamics simulations, including both ab initio studies used to interpret short-range interactions and classical simulations to describe longer range interactions. The higher level calculations highlight the presence of a strong hydrogen bond network within the ionic liquid, only slightly perturbed even at high acetonitrile concentration. These strong interactions lead to the symmetry breaking of the NO 3 - vibrations, with a splitting of about 88 cm -1 in the ν 3 antisymmetric stretch. The classical force field simulations use a greater number of ion pairs, but are not capable of fully describing the longest range interactions, although they do successfully account for the observed concentration trend, and the analysis of the models confirms the nano-inhomogeneity of these kinds of samples.

Structure and dynamics of propylammonium nitrate-acetonitrile mixtures: An intricate multi-scale system probed with experimental and theoretical techniques

NASA Astrophysics Data System (ADS)

Campetella, Marco; Mariani, Alessandro; Sadun, Claudia; Wu, Boning; Castner, Edward W.; Gontrani, Lorenzo

2018-04-01

In this article, we report the study of structural and dynamical properties for a series of acetonitrile/propylammonium nitrate mixtures as a function of their composition. These systems display an unusual increase in intensity in their X-ray diffraction patterns in the low-q regime, and their 1H-NMR diffusion-ordered NMR spectroscopy (DOSY) spectra display unusual diffusivities. However, the magnitude of both phenomena for mixtures of propylammonium nitrate is smaller than those observed for ethylammonium nitrate mixtures with the same cosolvent, suggesting that the cation alkyl tail plays an important role in these observations. The experimental X-ray scattering data are compared with the results of molecular dynamics simulations, including both ab initio studies used to interpret short-range interactions and classical simulations to describe longer range interactions. The higher level calculations highlight the presence of a strong hydrogen bond network within the ionic liquid, only slightly perturbed even at high acetonitrile concentration. These strong interactions lead to the symmetry breaking of the NO3 - vibrations, with a splitting of about 88 cm-1 in the ν3 antisymmetric stretch. The classical force field simulations use a greater number of ion pairs, but are not capable of fully describing the longest range interactions, although they do successfully account for the observed concentration trend, and the analysis of the models confirms the nano-inhomogeneity of these kinds of samples.

Evaluating methods for controlling depth perception in stereoscopic cinematography

NASA Astrophysics Data System (ADS)

Sun, Geng; Holliman, Nick

2009-02-01

Existing stereoscopic imaging algorithms can create static stereoscopic images with perceived depth control function to ensure a compelling 3D viewing experience without visual discomfort. However, current algorithms do not normally support standard Cinematic Storytelling techniques. These techniques, such as object movement, camera motion, and zooming, can result in dynamic scene depth change within and between a series of frames (shots) in stereoscopic cinematography. In this study, we empirically evaluate the following three types of stereoscopic imaging approaches that aim to address this problem. (1) Real-Eye Configuration: set camera separation equal to the nominal human eye interpupillary distance. The perceived depth on the display is identical to the scene depth without any distortion. (2) Mapping Algorithm: map the scene depth to a predefined range on the display to avoid excessive perceived depth. A new method that dynamically adjusts the depth mapping from scene space to display space is presented in addition to an existing fixed depth mapping method. (3) Depth of Field Simulation: apply Depth of Field (DOF) blur effect to stereoscopic images. Only objects that are inside the DOF are viewed in full sharpness. Objects that are far away from the focus plane are blurred. We performed a human-based trial using the ITU-R BT.500-11 Recommendation to compare the depth quality of stereoscopic video sequences generated by the above-mentioned imaging methods. Our results indicate that viewers' practical 3D viewing volumes are different for individual stereoscopic displays and viewers can cope with much larger perceived depth range in viewing stereoscopic cinematography in comparison to static stereoscopic images. Our new dynamic depth mapping method does have an advantage over the fixed depth mapping method in controlling stereo depth perception. The DOF blur effect does not provide the expected improvement for perceived depth quality control in 3D cinematography. We anticipate the results will be of particular interest to 3D filmmaking and real time computer games.

Long-range anticorrelations and non-Gaussian behavior of the heartbeat

NASA Technical Reports Server (NTRS)

Peng, C.-K.; Mietus, J.; Hausdorff, J. M.; Havlin, S.; Stanley, H. E.; Goldberger, A. L.

1993-01-01

We find that the successive increments in the cardiac beat-to-beat intervals of healthy subjects display scale-invariant, long-range anticorrelations (up to 10 exp 4 heart beats). Furthermore, we find that the histogram for the heartbeat intervals increments is well described by a Levy (1991) stable distribution. For a group of subjects with severe heart disease, we find that the distribution is unchanged, but the long-range correlations vanish. Therefore, the different scaling behavior in health and disease must relate to the underlying dynamics of the heartbeat.

Visual Acuity Using Head-fixed Displays During Passive Self and Surround Motion

NASA Technical Reports Server (NTRS)

Wood, Scott J.; Black, F. Owen; Stallings, Valerie; Peters, Brian

2007-01-01

The ability to read head-fixed displays on various motion platforms requires the suppression of vestibulo-ocular reflexes. This study examined dynamic visual acuity while viewing a head-fixed display during different self and surround rotation conditions. Twelve healthy subjects were asked to report the orientation of Landolt C optotypes presented on a micro-display fixed to a rotating chair at 50 cm distance. Acuity thresholds were determined by the lowest size at which the subjects correctly identified 3 of 5 optotype orientations at peak velocity. Visual acuity was compared across four different conditions, each tested at 0.05 and 0.4 Hz (peak amplitude of 57 deg/s). The four conditions included: subject rotated in semi-darkness (i.e., limited to background illumination of the display), subject stationary while visual scene rotated, subject rotated around a stationary visual background, and both subject and visual scene rotated together. Visual acuity performance was greatest when the subject rotated around a stationary visual background; i.e., when both vestibular and visual inputs provided concordant information about the motion. Visual acuity performance was most reduced when the subject and visual scene rotated together; i.e., when the visual scene provided discordant information about the motion. Ranges of 4-5 logMAR step sizes across the conditions indicated the acuity task was sufficient to discriminate visual performance levels. The background visual scene can influence the ability to read head-fixed displays during passive motion disturbances. Dynamic visual acuity using head-fixed displays can provide an operationally relevant screening tool for visual performance during exposure to novel acceleration environments.

Dynamic Skin Patterns in Cephalopods

PubMed Central

How, Martin J.; Norman, Mark D.; Finn, Julian; Chung, Wen-Sung; Marshall, N. Justin

2017-01-01

Cephalopods are unrivaled in the natural world in their ability to alter their visual appearance. These mollusks have evolved a complex system of dermal units under neural, hormonal, and muscular control to produce an astonishing variety of body patterns. With parallels to the pixels on a television screen, cephalopod chromatophores can be coordinated to produce dramatic, dynamic, and rhythmic displays, defined collectively here as “dynamic patterns.” This study examines the nature, context, and potential functions of dynamic patterns across diverse cephalopod taxa. Examples are presented for 21 species, including 11 previously unreported in the scientific literature. These range from simple flashing or flickering patterns, to highly complex passing wave patterns involving multiple skin fields. PMID:28674500

Micromachined mirrors for raster-scanning displays and optical fiber switches

NASA Astrophysics Data System (ADS)

Hagelin, Paul Merritt

Micromachines and micro-optics have the potential to shrink the size and cost of free-space optical systems, enabling a new generation of high-performance, compact projection displays and telecommunications equipment. In raster-scanning displays and optical fiber switches, a free-space optical beam can interact with multiple tilt- up micromirrors fabricated on a single substrate. The size, rotation angle, and flatness of the mirror surfaces determine the number of pixels in a raster-display or ports in an optical switch. Single-chip and two-chip optical raster display systems demonstrate static mirror curvature correction, an integrated electronic driver board, and dynamic micromirror performance. Correction for curvature caused by a stress gradient in the micromirror leads to resolution of 102 by 119 pixels in the single-chip display. The optical design of the two-chip display features in-situ mirror curvature measurement and adjustable image magnification with a single output lens. An electronic driver board synchronizes modulation of the optical source with micromirror actuation for the display of images. Dynamic off-axis mirror motion is shown to have minimal influence on resolution. The confocal switch, a free-space optical fiber cross- connect, incorporates micromirrors having a design similar to the image-refresh scanner. Two micromirror arrays redirect optical beams from an input fiber array to the output fibers. The switch architecture supports simultaneous switching of multiple wavelength channels. A 2x2 switch configuration, using single-mode optical fiber at 1550 mn, is demonstrated with insertion loss of -4.2 dB and cross-talk of -50.5 dB. The micromirrors have sufficient size and angular range for scaling to a 32x32 cross-connect switch that has low insertion-loss and low cross-talk.

Effects of pressure on the dynamics of a hyperthermophilic protein revealed by quasielastic neutron scattering

NASA Astrophysics Data System (ADS)

Shrestha, U. R.; Bhowmik, D.; Copley, J. R. D.; Tyagi, M.; Leao, J. B.; Chu, X.-Q.

Inorganic pyrophosphatase (IPPase) from Thermococcus thioreducens is a large oligomeric protein derived from hyperthermophilic microorganism that is found near hydrothermal vents deep under the sea, where the pressure is nearly 100 MPa. Here we study the effects of pressure on the conformational flexibility and relaxation dynamics of IPPase over a wide temperature range using quasielastic neutron scattering (QENS) technique. Two spectrometers were used to investigate the β-relaxation dynamics of proteins in time ranges from 2 to 25 ps, and from 100 ps to 2 ns. Our results reveal that, under the pressure of 100 MPa, IPPase displays much faster relaxation dynamics than a mesophilic model protein, hen egg white lysozyme (HEWL), opposite to what we observed previously under the ambient pressure. These contradictory observations imply that high pressure affects the dynamical properties of proteins by distorting their energy landscapes. Accordingly, we derived a general schematic denaturation phase diagram that can be used as a general picture to understand the effects of pressure on protein dynamics and activities Wayne State Univ Startup Fund.

Merging constitutional and motional covalent dynamics in reversible imine formation and exchange processes.

PubMed

Kovaříček, Petr; Lehn, Jean-Marie

2012-06-06

The formation and exchange processes of imines of salicylaldehyde, pyridine-2-carboxaldehyde, and benzaldehyde have been studied, showing that the former has features of particular interest for dynamic covalent chemistry, displaying high efficiency and fast rates. The monoimines formed with aliphatic α,ω-diamines display an internal exchange process of self-transimination type, inducing a local motion of either "stepping-in-place" or "single-step" type by bond interchange, whose rate decreases rapidly with the distance of the terminal amino groups. Control of the speed of the process over a wide range may be achieved by substituents, solvent composition, and temperature. These monoimines also undergo intermolecular exchange, thus merging motional and constitutional covalent behavior within the same molecule. With polyamines, the monoimines formed execute internal motions that have been characterized by extensive one-dimensional, two-dimensional, and EXSY proton NMR studies. In particular, with linear polyamines, nondirectional displacement occurs by shifting of the aldehyde residue along the polyamine chain serving as molecular track. Imines thus behave as simple prototypes of systems displaying relative motions of molecular moieties, a subject of high current interest in the investigation of synthetic and biological molecular motors. The motional processes described are of dynamic covalent nature and take place without change in molecular constitution. They thus represent a category of dynamic covalent motions, resulting from reversible covalent bond formation and dissociation. They extend dynamic covalent chemistry into the area of molecular motions. A major further step will be to achieve control of directionality. The results reported here for imines open wide perspectives, together with other chemical groups, for the implementation of such features in multifunctional molecules toward the design of molecular devices presenting a complex combination of motional and constitutional dynamic behaviors.

Does Mckuer's Law Hold for Heart Rate Control via Biofeedback Display?

NASA Technical Reports Server (NTRS)

Courter, B. J.; Jex, H. R.

1984-01-01

Some persons can control their pulse rate with the aid of a biofeedback display. If the biofeedback display is modified to show the error between a command pulse-rate and the measured rate, a compensatory (error correcting) heart rate tracking control loop can be created. The dynamic response characteristics of this control loop when subjected to step and quasi-random disturbances were measured. The control loop includes a beat-to-beat cardiotachmeter differenced with a forcing function from a quasi-random input generator; the resulting error pulse-rate is displayed as feedback. The subject acts to null the displayed pulse-rate error, thereby closing a compensatory control loop. McRuer's Law should hold for this case. A few subjects already skilled in voluntary pulse-rate control were tested for heart-rate control response. Control-law properties are derived, such as: crossover frequency, stability margins, and closed-loop bandwidth. These are evaluated for a range of forcing functions and for step as well as random disturbances.

Improvements in hover display dynamics for a combat helicopter

NASA Technical Reports Server (NTRS)

Eshow, Michelle M.; Schroeder, Jeffery A.

1993-01-01

This paper describes a piloted simulation conducted on the NASA Ames Vertical Motion Simulator. The objective of the experiment was to investigate the handling qualities benefits attainable using new display law design methods for hover displays. The new display laws provide improved methods to specify the behavior of the display symbol that predicts the vehicle's ground velocity in the horizontal plane; it is the primary symbol that the pilot uses to control aircraft horizontal position. The display law design was applied to the Apache helmet-mounted display format, using the Apache vehicle dynamics to tailor the dynamics of the velocity predictor symbol. The representations of the Apache vehicle used in the display design process and in the simulation were derived from flight data. During the simulation, the new symbol dynamics were seen to improve the pilots' ability to maneuver about hover in poor visual cuing environments. The improvements were manifested in pilot handling qualities ratings and in measured task performance. The paper details the display design techniques, the experiment design and conduct, and the results.

An experimental study of dynamic stall on advanced airfoil section. Volume 2: Pressure and force data

NASA Technical Reports Server (NTRS)

Mcalister, K. W.; Pucci, S. L.; Mccroskey, W. J.; Carr, L. W.

1982-01-01

Experimentally derived force and moment data are presented for eight airfoil sections that were tested at fixed and varying incidence in a subsonic two dimensional stream. Airfoil incidence was varied through sinusoidal oscillations in pitch over a wide range of amplitude and frequency. The surface pressure distribution, as well as the lift, drag, and pitching moment derived therefrom, are displayed in a uniform fashion to delineate the static and dynamic characteristics of each airfoil both in and out of stall.

Tangible display systems: direct interfaces for computer-based studies of surface appearance

NASA Astrophysics Data System (ADS)

Darling, Benjamin A.; Ferwerda, James A.

2010-02-01

When evaluating the surface appearance of real objects, observers engage in complex behaviors involving active manipulation and dynamic viewpoint changes that allow them to observe the changing patterns of surface reflections. We are developing a class of tangible display systems to provide these natural modes of interaction in computer-based studies of material perception. A first-generation tangible display was created from an off-the-shelf laptop computer containing an accelerometer and webcam as standard components. Using these devices, custom software estimated the orientation of the display and the user's viewing position. This information was integrated with a 3D rendering module so that rotating the display or moving in front of the screen would produce realistic changes in the appearance of virtual objects. In this paper, we consider the design of a second-generation system to improve the fidelity of the virtual surfaces rendered to the screen. With a high-quality display screen and enhanced tracking and rendering capabilities, a secondgeneration system will be better able to support a range of appearance perception applications.

Human-display interactions: Context-specific biases

NASA Technical Reports Server (NTRS)

Kaiser, Mary Kister; Proffitt, Dennis R.

1987-01-01

Recent developments in computer engineering have greatly enhanced the capabilities of display technology. As displays are no longer limited to simple alphanumeric output, they can present a wide variety of graphic information, using either static or dynamic presentation modes. At the same time that interface designers exploit the increased capabilities of these displays, they must be aware of the inherent limitation of these displays. Generally, these limitations can be divided into those that reflect limitations of the medium (e.g., reducing three-dimensional representations onto a two-dimensional projection) and those reflecting the perceptual and conceptual biases of the operator. The advantages and limitations of static and dynamic graphic displays are considered. Rather than enter into the discussion of whether dynamic or static displays are superior, general advantages and limitations are explored which are contextually specific to each type of display.

Active confocal imaging for visual prostheses

PubMed Central

Jung, Jae-Hyun; Aloni, Doron; Yitzhaky, Yitzhak; Peli, Eli

2014-01-01

There are encouraging advances in prosthetic vision for the blind, including retinal and cortical implants, and other “sensory substitution devices” that use tactile or electrical stimulation. However, they all have low resolution, limited visual field, and can display only few gray levels (limited dynamic range), severely restricting their utility. To overcome these limitations, image processing or the imaging system could emphasize objects of interest and suppress the background clutter. We propose an active confocal imaging system based on light-field technology that will enable a blind user of any visual prosthesis to efficiently scan, focus on, and “see” only an object of interest while suppressing interference from background clutter. The system captures three-dimensional scene information using a light-field sensor and displays only an in-focused plane with objects in it. After capturing a confocal image, a de-cluttering process removes the clutter based on blur difference. In preliminary experiments we verified the positive impact of confocal-based background clutter removal on recognition of objects in low resolution and limited dynamic range simulated phosphene images. Using a custom-made multiple-camera system, we confirmed that the concept of a confocal de-cluttered image can be realized effectively using light field imaging. PMID:25448710

Elevated temperature tensile properties of P9 steel towards ferritic steel wrapper development for sodium cooled fast reactors

NASA Astrophysics Data System (ADS)

Choudhary, B. K.; Mathew, M. D.; Isaac Samuel, E.; Christopher, J.; Jayakumar, T.

2013-11-01

Tensile deformation and fracture behaviour of the three developmental heats of P9 steel for wrapper applications containing varying silicon in the range 0.24-0.60% have been examined in the temperature range 300-873 K. Yield and ultimate tensile strengths in all the three heats exhibited gradual decrease with increase in temperature from room to intermediate temperatures followed by rapid decrease at high temperatures. A gradual decrease in ductility to a minimum at intermediate temperatures followed by an increase at high temperatures has been observed. The fracture mode remained transgranular ductile. The steel displayed signatures of dynamic strain ageing at intermediate temperatures and dominance of recovery at high temperatures. No significant difference in the strength and ductility values was observed for varying silicon in the range 0.24-0.60% in P9 steel. P9 steel for wrapper application displayed strength and ductility values comparable to those reported in the literature.

Effect of Display Color on Pilot Performance and Describing Functions

NASA Technical Reports Server (NTRS)

Chase, Wendell D.

1997-01-01

A study has been conducted with the full-spectrum, calligraphic, computer-generated display system to determine the effect of chromatic content of the visual display upon pilot performance during the landing approach maneuver. This study utilizes a new digital chromatic display system, which has previously been shown to improve the perceived fidelity of out-the-window display scenes, and presents the results of an experiment designed to determine the effects of display color content by the measurement of both vertical approach performance and pilot-describing functions. This method was selected to more fully explore the effects of visual color cues used by the pilot. Two types of landing approaches were made: dynamic and frozen range, with either a landing approach scene or a perspective array display. The landing approach scene was presented with either red runway lights and blue taxiway lights or with the colors reversed, and the perspective array with red lights, blue lights, or red and blue lights combined. The vertical performance measures obtained in this experiment indicated that the pilots performed best with the blue and red/blue displays. and worst with the red displays. The describing-function system analysis showed more variation with the red displays. The crossover frequencies were lowest with the red displays and highest with the combined red/blue displays, which provided the best overall tracking, performance. Describing-function performance measures, vertical performance measures, and pilot opinion support the hypothesis that specific colors in displays can influence the pilots' control characteristics during the final approach.

The nonlinear wave equation for higher harmonics in free-electron lasers

NASA Technical Reports Server (NTRS)

Colson, W. B.

1981-01-01

The nonlinear wave equation and self-consistent pendulum equation are generalized to describe free-electron laser operation in higher harmonics; this can significantly extend their tunable range to shorter wavelengths. The dynamics of the laser field's amplitude and phase are explored for a wide range of parameters using families of normalized gain curves applicable to both the fundamental and harmonics. The electron phase-space displays the fundamental physics driving the wave, and this picture is used to distinguish between the effects of high gain and Coulomb forces.

New segmentation-based tone mapping algorithm for high dynamic range image

NASA Astrophysics Data System (ADS)

Duan, Weiwei; Guo, Huinan; Zhou, Zuofeng; Huang, Huimin; Cao, Jianzhong

2017-07-01

The traditional tone mapping algorithm for the display of high dynamic range (HDR) image has the drawback of losing the impression of brightness, contrast and color information. To overcome this phenomenon, we propose a new tone mapping algorithm based on dividing the image into different exposure regions in this paper. Firstly, the over-exposure region is determined using the Local Binary Pattern information of HDR image. Then, based on the peak and average gray of the histogram, the under-exposure and normal-exposure region of HDR image are selected separately. Finally, the different exposure regions are mapped by differentiated tone mapping methods to get the final result. The experiment results show that the proposed algorithm achieve the better performance both in visual quality and objective contrast criterion than other algorithms.

Beyond harmonic sounds in a simple model for birdsong production.

PubMed

Amador, Ana; Mindlin, Gabriel B

2008-12-01

In this work we present an analysis of the dynamics displayed by a simple bidimensional model of labial oscillations during birdsong production. We show that the same model capable of generating tonal sounds can present, for a wide range of parameters, solutions which are spectrally rich. The role of physiologically sensible parameters is discussed in each oscillatory regime, allowing us to interpret previously reported data.

Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces

PubMed Central

Franklin, Daniel; Chen, Yuan; Vazquez-Guardado, Abraham; Modak, Sushrut; Boroumand, Javaneh; Xu, Daming; Wu, Shin-Tson; Chanda, Debashis

2015-01-01

Structural colour arising from nanostructured metallic surfaces offers many benefits compared to conventional pigmentation based display technologies, such as increased resolution and scalability of their optical response with structure dimensions. However, once these structures are fabricated their optical characteristics remain static, limiting their potential application. Here, by using a specially designed nanostructured plasmonic surface in conjunction with high birefringence liquid crystals, we demonstrate a tunable polarization-independent reflective surface where the colour of the surface is changed as a function of applied voltage. A large range of colour tunability is achieved over previous reports by utilizing an engineered surface which allows full liquid crystal reorientation while maximizing the overlap between plasmonic fields and liquid crystal. In combination with imprinted structures of varying periods, a full range of colours spanning the entire visible spectrum is achieved, paving the way towards dynamic pixels for reflective displays. PMID:26066375

Dynamic Displays Enhance the Ability to Discriminate Genuine and Posed Facial Expressions of Emotion

PubMed Central

Namba, Shushi; Kabir, Russell S.; Miyatani, Makoto; Nakao, Takashi

2018-01-01

Accurately gauging the emotional experience of another person is important for navigating interpersonal interactions. This study investigated whether perceivers are capable of distinguishing between unintentionally expressed (genuine) and intentionally manipulated (posed) facial expressions attributed to four major emotions: amusement, disgust, sadness, and surprise. Sensitivity to this discrimination was explored by comparing unstaged dynamic and static facial stimuli and analyzing the results with signal detection theory. Participants indicated whether facial stimuli presented on a screen depicted a person showing a given emotion and whether that person was feeling a given emotion. The results showed that genuine displays were evaluated more as felt expressions than posed displays for all target emotions presented. In addition, sensitivity to the perception of emotional experience, or discriminability, was enhanced in dynamic facial displays, but was less pronounced in the case of static displays. This finding indicates that dynamic information in facial displays contributes to the ability to accurately infer the emotional experiences of another person. PMID:29896135

Symmetric linear systems - An application of algebraic systems theory

NASA Technical Reports Server (NTRS)

Hazewinkel, M.; Martin, C.

1983-01-01

Dynamical systems which contain several identical subsystems occur in a variety of applications ranging from command and control systems and discretization of partial differential equations, to the stability augmentation of pairs of helicopters lifting a large mass. Linear models for such systems display certain obvious symmetries. In this paper, we discuss how these symmetries can be incorporated into a mathematical model that utilizes the modern theory of algebraic systems. Such systems are inherently related to the representation theory of algebras over fields. We will show that any control scheme which respects the dynamical structure either implicitly or explicitly uses the underlying algebra.

Cropland land surface phenology and seasonality in East Africa: Ethiopia, Tanzania, and South Sudan

NASA Astrophysics Data System (ADS)

Alemu, W. G.; Henebry, G. M.

2015-12-01

Most people in East Africa depend on rainfed agriculture. Rainfall in the region has been decreasing recently and is highly variable in space and time leading to high food insecurity. A comprehensive understanding of the regional cropland dynamics is therefore needed. Land surface phenology and land surface seasonality have important roles in monitoring cropland dynamics in a region with sparse coverage of in situ climatic and biophysical observations. However, commonly used optical satellite data are often degraded by cloud cover, aerosols, and dust and they are restricted to daytime observations. Here we used near-daily passive microwave (PM) data at 25 km spatial resolution from a series of microwave radiometers—AMSR-E, FengYun3B/MWRI, AMSR2—to study cropland dynamics for 2003-2013 in three important grain production areas of East Africa: Ethiopia, Tanzania, and South Sudan. PM data can be collected through clouds and at night. Based on Google Earth imagery, we identified several cropland areas corresponding to PM grid cells. Rainfall from TRMM and atmospheric water vapor (V) from PM data displayed temporal patterns that were unimodal in Ethiopia and South Sudan, but bimodal in Tanzania. We fitted convex quadratic models to link growing season increments of V and vegetation optical depth (VOD) to accumulated V (AV). The models yielded high coefficients of determination (r2 ≥0.8) and phenometrics calculated from the parameter coefficients. Peak rainfall lagged peak V, but preceded peak VOD. Growing degree-days (GDD), calculated from the PM air temperature data, displayed a weaker bimodal seasonality in which the lowest values occurred during the peak rainy season, due to the cooling effect of latent heat flux and coupled with higher reflection of insolation by the cloud deck. V as a function of GDD displays quasi-periodic behavior. Drier sites in the region displayed larger (smaller) intra-annual dynamic range of V (GDD) compared to the moister sites.

Development of a multipurpose scaffold for the display of peptide loops

PubMed Central

Rossmann, Maxim; J. Greive, Sandra; Moschetti, Tommaso; Dinan, Michael

2017-01-01

Abstract Protein–protein interactions (PPIs) determine a wide range of biological processes and analysis of these dynamic networks is increasingly becoming a mandatory tool for studying protein function. Using the globular ATPase domain of recombinase RadA as a scaffold, we have developed a peptide display system (RAD display), which allows for the presentation of target peptides, protein domains or full-length proteins and their rapid recombinant production in bacteria. The design of the RAD display system includes differently tagged versions of the scaffold, which allows for flexibility in the protein purification method, and chemical coupling for small molecule labeling or surface immobilization. When combined with the significant thermal stability of the RadA protein, these features create a versatile multipurpose scaffold system. Using various orthogonal biophysical techniques, we show that peptides displayed on the scaffold bind to their natural targets in a fashion similar to linear parent peptides. We use the examples of CK2β/CK2α kinase and TPX2/Aurora A kinase protein complexes to demonstrate that the peptide displayed by the RAD scaffold can be used in PPI studies with the same binding efficacy but at lower costs compared with their linear synthetic counterparts. PMID:28444399

In situ two-dimensional imaging quick-scanning XAFS with pixel array detector.

PubMed

Tanida, Hajime; Yamashige, Hisao; Orikasa, Yuki; Oishi, Masatsugu; Takanashi, Yu; Fujimoto, Takahiro; Sato, Kenji; Takamatsu, Daiko; Murayama, Haruno; Arai, Hajime; Matsubara, Eiichiro; Uchimoto, Yoshiharu; Ogumi, Zempachi

2011-11-01

Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2 mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10 s to 1 min per spectrum depending on the energy range. The PAD has a wide dynamic range and low noise, so the obtained spectra have a good signal-to-noise ratio.

Dynamic plasmonic colour display

NASA Astrophysics Data System (ADS)

Duan, Xiaoyang; Kamin, Simon; Liu, Na

2017-02-01

Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications.

Dynamic plasmonic colour display.

PubMed

Duan, Xiaoyang; Kamin, Simon; Liu, Na

2017-02-24

Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications.

Dynamic plasmonic colour display

PubMed Central

Duan, Xiaoyang; Kamin, Simon; Liu, Na

2017-01-01

Plasmonic colour printing based on engineered metasurfaces has revolutionized colour display science due to its unprecedented subwavelength resolution and high-density optical data storage. However, advanced plasmonic displays with novel functionalities including dynamic multicolour printing, animations, and highly secure encryption have remained in their infancy. Here we demonstrate a dynamic plasmonic colour display technique that enables all the aforementioned functionalities using catalytic magnesium metasurfaces. Controlled hydrogenation and dehydrogenation of the constituent magnesium nanoparticles, which serve as dynamic pixels, allow for plasmonic colour printing, tuning, erasing and restoration of colour. Different dynamic pixels feature distinct colour transformation kinetics, enabling plasmonic animations. Through smart material processing, information encoded on selected pixels, which are indiscernible to both optical and scanning electron microscopies, can only be read out using hydrogen as a decoding key, suggesting a new generation of information encryption and anti-counterfeiting applications. PMID:28232722

Advanced Plasmonic Materials for Dynamic Color Display.

PubMed

Shao, Lei; Zhuo, Xiaolu; Wang, Jianfang

2018-04-01

Plasmonic structures exhibit promising applications in high-resolution and durable color generation. Research on advanced hybrid plasmonic materials that allow dynamically reconfigurable color control has developed rapidly in recent years. Some of these results may give rise to practically applicable reflective displays in living colors with high performance and low power consumption. They will attract broad interest from display markets, compared with static plasmonic color printing, for example, in applications such as digital signage, full-color electronic paper, and electronic device screens. In this progress report, the most promising recent examples of utilizing advanced plasmonic materials for the realization of dynamic color display are highlighted and put into perspective. The performances, advantages, and disadvantages of different technologies are discussed, with emphasis placed on both the potential and possible limitations of various hybrid materials for dynamic plasmonic color display. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Conformational analysis of processivity clamps in solution demonstrates that tertiary structure does not correlate with protein dynamics.

PubMed

Fang, Jing; Nevin, Philip; Kairys, Visvaldas; Venclovas, Česlovas; Engen, John R; Beuning, Penny J

2014-04-08

The relationship between protein sequence, structure, and dynamics has been elusive. Here, we report a comprehensive analysis using an in-solution experimental approach to study how the conservation of tertiary structure correlates with protein dynamics. Hydrogen exchange measurements of eight processivity clamp proteins from different species revealed that, despite highly similar three-dimensional structures, clamp proteins display a wide range of dynamic behavior. Differences were apparent both for structurally similar domains within proteins and for corresponding domains of different proteins. Several of the clamps contained regions that underwent local unfolding with different half-lives. We also observed a conserved pattern of alternating dynamics of the α helices lining the inner pore of the clamps as well as a correlation between dynamics and the number of salt bridges in these α helices. Our observations reveal that tertiary structure and dynamics are not directly correlated and that primary structure plays an important role in dynamics. Copyright © 2014 Elsevier Ltd. All rights reserved.

Color transfer between high-dynamic-range images

NASA Astrophysics Data System (ADS)

Hristova, Hristina; Cozot, Rémi; Le Meur, Olivier; Bouatouch, Kadi

2015-09-01

Color transfer methods alter the look of a source image with regards to a reference image. So far, the proposed color transfer methods have been limited to low-dynamic-range (LDR) images. Unlike LDR images, which are display-dependent, high-dynamic-range (HDR) images contain real physical values of the world luminance and are able to capture high luminance variations and finest details of real world scenes. Therefore, there exists a strong discrepancy between the two types of images. In this paper, we bridge the gap between the color transfer domain and the HDR imagery by introducing HDR extensions to LDR color transfer methods. We tackle the main issues of applying a color transfer between two HDR images. First, to address the nature of light and color distributions in the context of HDR imagery, we carry out modifications of traditional color spaces. Furthermore, we ensure high precision in the quantization of the dynamic range for histogram computations. As image clustering (based on light and colors) proved to be an important aspect of color transfer, we analyze it and adapt it to the HDR domain. Our framework has been applied to several state-of-the-art color transfer methods. Qualitative experiments have shown that results obtained with the proposed adaptation approach exhibit less artifacts and are visually more pleasing than results obtained when straightforwardly applying existing color transfer methods to HDR images.

Lessons from Jurassic Park: patients as complex adaptive systems.

PubMed

Katerndahl, David A

2009-08-01

With realization that non-linearity is generally the rule rather than the exception in nature, viewing patients and families as complex adaptive systems may lead to a better understanding of health and illness. Doctors who successfully practise the 'art' of medicine may recognize non-linear principles at work without having the jargon needed to label them. Complex adaptive systems are systems composed of multiple components that display complexity and adaptation to input. These systems consist of self-organized components, which display complex dynamics, ranging from simple periodicity to chaotic and random patterns showing trends over time. Understanding the non-linear dynamics of phenomena both internal and external to our patients can (1) improve our definition of 'health'; (2) improve our understanding of patients, disease and the systems in which they converge; (3) be applied to future monitoring systems; and (4) be used to possibly engineer change. Such a non-linear view of the world is quite congruent with the generalist perspective.

Dynamic message sign message design and display manual training : participant notebook, two-day course.

DOT National Transportation Integrated Search

2009-03-01

This Dynamic Message Sign Message Design and Display Manual was written for use by Texas Department of : Transportation (TxDOT) personnel who have responsibility for the operation of and/or message design for large : permanent dynamic message signs (...

Self-diffusion and microscopic dynamics in a gold-silicon liquid investigated with quasielastic neutron scattering

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

Evenson, Zach, E-mail: Zachary.Evenson@frm2.tum.de; Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt; Yang, Fan

2016-03-21

We use incoherent quasielastic neutron scattering to study the atomic dynamics of gold in a eutectic Au{sub 81}Si{sub 19} melt. Despite the glass-forming nature of this system, the gold self-diffusivity displays an Arrhenius behavior with a low activation energy characteristic of simple liquids. At high temperatures, long-range transport of gold atoms is well described by hydrodynamic theory with a simple exponential decay of the self-correlation function. On cooling towards the melting temperature, structural relaxation crosses over to a highly stretched exponential behavior. This suggests the onset of a heterogeneous dynamics, even in the equilibrium melt, and is indicative of amore » very fragile liquid.« less

Atomic switch networks as complex adaptive systems

NASA Astrophysics Data System (ADS)

Scharnhorst, Kelsey S.; Carbajal, Juan P.; Aguilera, Renato C.; Sandouk, Eric J.; Aono, Masakazu; Stieg, Adam Z.; Gimzewski, James K.

2018-03-01

Complexity is an increasingly crucial aspect of societal, environmental and biological phenomena. Using a dense unorganized network of synthetic synapses it is shown that a complex adaptive system can be physically created on a microchip built especially for complex problems. These neuro-inspired atomic switch networks (ASNs) are a dynamic system with inherent and distributed memory, recurrent pathways, and up to a billion interacting elements. We demonstrate key parameters describing self-organized behavior such as non-linearity, power law dynamics, and multistate switching regimes. Device dynamics are then investigated using a feedback loop which provides control over current and voltage power-law behavior. Wide ranging prospective applications include understanding and eventually predicting future events that display complex emergent behavior in the critical regime.

An evaluation of dynamic lip-tooth characteristics during speech and smile in adolescents.

PubMed

Ackerman, Marc B; Brensinger, Colleen; Landis, J Richard

2004-02-01

This retrospective study was conducted to measure lip-tooth characteristics of adolescents. Pretreatment video clips of 1242 consecutive patients were screened for Class-I skeletal and dental patterns. After all inclusion criteria were applied, the final sample consisted of 50 patients (27 boys, 23 girls) with a mean age of 12.5 years. The raw digital video stream of each patient was edited to select a single image frame representing the patient saying the syllable "chee" and a second single image representing the patient's posed social smile and saved as part of a 12-frame image sequence. Each animation image was analyzed using a SmileMesh computer application to measure the smile index (the ratio of the intercommissure width divided by the interlabial gap), intercommissure width (mm), interlabial gap (mm), percent incisor below the intercommissure line, and maximum incisor exposure (mm). The data were analyzed using SAS (version 8.1). All recorded differences in linear measures had to be > or = 2 mm. The results suggest that anterior tooth display at speech and smile should be recorded independently but evaluated as part of a dynamic range. Asking patients to say "cheese" and then smile is no longer a valid method to elicit the parameters of anterior tooth display. When planning the vertical positions of incisors during orthodontic treatment, the orthodontist should view the dynamics of anterior tooth display as a continuum delineated by the time points of rest, speech, posed social smile, and a Duchenne smile.

A potential non-invasive approach to evaluating blastocyst quality using biodynamic imaging

NASA Astrophysics Data System (ADS)

Li, Zhe; Ehmke, Natalie; Machaty, Zoltan; Nolte, David

2018-02-01

Biodynamic imaging (BDI) is capable of capturing the intracellular dynamics of blastocysts within a relatively short time. Spectroscopic signatures of embryos in the 0.01 Hz - 1 Hz range display responses to external factors before morphology changes take place. Viability evaluation is consistent with results from other non-invasive methods. Biodynamic imaging is a potential tool for selecting high quality embryos in clinical IVF practices.

Effects of Scene Modulation Image Blur and Noise Upon Human Target Acquisition Performance.

DTIC Science & Technology

1997-06-01

AFRL-HE-WP-TR-1998-0012 UNITED STATES AIR FORCE RESEARCH LABORATORY EFFECTS OF SCENE MODULATION IMAGE BLUR AND NOISE UPON HUMAN TARGET...COVERED INTERIM (July 1996 - August 1996) TITLE AND SUBTITLE Effects of Scene Modulation Image Blur and Noise Upon Human Target Acquisition...dilemma in image transmission and display is that we must compromise between die conflicting constraints of dynamic range and noise . Three target

A JPEG backward-compatible HDR image compression

NASA Astrophysics Data System (ADS)

Korshunov, Pavel; Ebrahimi, Touradj

2012-10-01

High Dynamic Range (HDR) imaging is expected to become one of the technologies that could shape next generation of consumer digital photography. Manufacturers are rolling out cameras and displays capable of capturing and rendering HDR images. The popularity and full public adoption of HDR content is however hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of Low Dynamic Range (LDR) displays that are unable to render HDR. To facilitate wide spread of HDR usage, the backward compatibility of HDR technology with commonly used legacy image storage, rendering, and compression is necessary. Although many tone-mapping algorithms were developed for generating viewable LDR images from HDR content, there is no consensus on which algorithm to use and under which conditions. This paper, via a series of subjective evaluations, demonstrates the dependency of perceived quality of the tone-mapped LDR images on environmental parameters and image content. Based on the results of subjective tests, it proposes to extend JPEG file format, as the most popular image format, in a backward compatible manner to also deal with HDR pictures. To this end, the paper provides an architecture to achieve such backward compatibility with JPEG and demonstrates efficiency of a simple implementation of this framework when compared to the state of the art HDR image compression.

Undifferentiated Facial Electromyography Responses to Dynamic, Audio-Visual Emotion Displays in Individuals with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Rozga, Agata; King, Tricia Z.; Vuduc, Richard W.; Robins, Diana L.

2013-01-01

We examined facial electromyography (fEMG) activity to dynamic, audio-visual emotional displays in individuals with autism spectrum disorders (ASD) and typically developing (TD) individuals. Participants viewed clips of happy, angry, and fearful displays that contained both facial expression and affective prosody while surface electrodes measured…

Lightweight genome viewer: portable software for browsing genomics data in its chromosomal context

PubMed Central

Faith, Jeremiah J; Olson, Andrew J; Gardner, Timothy S; Sachidanandam, Ravi

2007-01-01

Background Lightweight genome viewer (lwgv) is a web-based tool for visualization of sequence annotations in their chromosomal context. It performs most of the functions of larger genome browsers, while relying on standard flat-file formats and bypassing the database needs of most visualization tools. Visualization as an aide to discovery requires display of novel data in conjunction with static annotations in their chromosomal context. With database-based systems, displaying dynamic results requires temporary tables that need to be tracked for removal. Results lwgv simplifies the visualization of user-generated results on a local computer. The dynamic results of these analyses are written to transient files, which can import static content from a more permanent file. lwgv is currently used in many different applications, from whole genome browsers to single-gene RNAi design visualization, demonstrating its applicability in a large variety of contexts and scales. Conclusion lwgv provides a lightweight alternative to large genome browsers for visualizing biological annotations and dynamic analyses in their chromosomal context. It is particularly suited for applications ranging from short sequences to medium-sized genomes when the creation and maintenance of a large software and database infrastructure is not necessary or desired. PMID:17877794

Lightweight genome viewer: portable software for browsing genomics data in its chromosomal context.

PubMed

Faith, Jeremiah J; Olson, Andrew J; Gardner, Timothy S; Sachidanandam, Ravi

2007-09-18

Lightweight genome viewer (lwgv) is a web-based tool for visualization of sequence annotations in their chromosomal context. It performs most of the functions of larger genome browsers, while relying on standard flat-file formats and bypassing the database needs of most visualization tools. Visualization as an aide to discovery requires display of novel data in conjunction with static annotations in their chromosomal context. With database-based systems, displaying dynamic results requires temporary tables that need to be tracked for removal. lwgv simplifies the visualization of user-generated results on a local computer. The dynamic results of these analyses are written to transient files, which can import static content from a more permanent file. lwgv is currently used in many different applications, from whole genome browsers to single-gene RNAi design visualization, demonstrating its applicability in a large variety of contexts and scales. lwgv provides a lightweight alternative to large genome browsers for visualizing biological annotations and dynamic analyses in their chromosomal context. It is particularly suited for applications ranging from short sequences to medium-sized genomes when the creation and maintenance of a large software and database infrastructure is not necessary or desired.

A fast and automatic fusion algorithm for unregistered multi-exposure image sequence

NASA Astrophysics Data System (ADS)

Liu, Yan; Yu, Feihong

2014-09-01

Human visual system (HVS) can visualize all the brightness levels of the scene through visual adaptation. However, the dynamic range of most commercial digital cameras and display devices are smaller than the dynamic range of human eye. This implies low dynamic range (LDR) images captured by normal digital camera may lose image details. We propose an efficient approach to high dynamic (HDR) image fusion that copes with image displacement and image blur degradation in a computationally efficient manner, which is suitable for implementation on mobile devices. The various image registration algorithms proposed in the previous literatures are unable to meet the efficiency and performance requirements in the application of mobile devices. In this paper, we selected Oriented Brief (ORB) detector to extract local image structures. The descriptor selected in multi-exposure image fusion algorithm has to be fast and robust to illumination variations and geometric deformations. ORB descriptor is the best candidate in our algorithm. Further, we perform an improved RANdom Sample Consensus (RANSAC) algorithm to reject incorrect matches. For the fusion of images, a new approach based on Stationary Wavelet Transform (SWT) is used. The experimental results demonstrate that the proposed algorithm generates high quality images at low computational cost. Comparisons with a number of other feature matching methods show that our method gets better performance.

Dynamic message sign message design and display manual training : participant notebook, one-day "core" course.

DOT National Transportation Integrated Search

2009-03-01

This Dynamic Message Sign Message Design and Display Manual was written for use by Texas Department of Transportation (TxDOT) personnel who have responsibility for the operation of and/or message design for large permanent dynamic message signs (DMSs...

Comparative study of thiophilic functionalised matrices for polyclonal F(ab')2 purification.

PubMed

Kumpalume, Peter; Slater, Nigel K H

2004-01-02

Thiophilic adsorbents have been developed using divinyl sulfone or epoxy activated Streamline quartz base matrix. Their capacity and selectivity for binding polyclonal F(ab')2 fragments generated by whole serum proteolysis was tested. Except for epoxy activated guanidine, all the adsorbents displayed high selectivity for F(ab')2 with dynamic binding capacities ranging from 3 to 10 mg/ml of adsorbent. Thiol immobilised ligands adsorbed more F(ab')2 and the recovery was equal to or more than that from amino immobilised ligands. All adsorbents showed good selectivity for IgG and the dynamic binding capacities were better than for F(ab')2.

Identification of the low-energy excitations in a quantum critical system

NASA Astrophysics Data System (ADS)

Heitmann, Tom; Lamsal, Jagat; Watson, Shannon; Erwin, Ross; Chen, Wangchun; Zhao, Yang; Montfrooij, Wouter

2017-05-01

We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Ce(Fe0.76Ru0.24)2Ge2 displays dynamical scaling in the absence of local critical behavior or long-range spin-density wave criticality. The low-energy excitations are associated with the reorientations of the superspins of fully ordered, isolated magnetic clusters that form spontaneously upon lowering the temperature. The system houses both frozen clusters and dynamic clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401(R) (2006)].

A human factors approach to range scheduling for satellite control

NASA Technical Reports Server (NTRS)

Wright, Cameron H. G.; Aitken, Donald J.

1991-01-01

Range scheduling for satellite control presents a classical problem: supervisory control of a large-scale dynamic system, with unwieldy amounts of interrelated data used as inputs to the decision process. Increased automation of the task, with the appropriate human-computer interface, is highly desirable. The development and user evaluation of a semi-automated network range scheduling system is described. The system incorporates a synergistic human-computer interface consisting of a large screen color display, voice input/output, a 'sonic pen' pointing device, a touchscreen color CRT, and a standard keyboard. From a human factors standpoint, this development represents the first major improvement in almost 30 years to the satellite control network scheduling task.

Ab initio molecular dynamic study of solid-state transitions of ammonium nitrate

PubMed Central

Yu, Hongyu; Duan, Defang; Liu, Hanyu; Yang, Ting; Tian, Fubo; Bao, Kuo; Li, Da; Zhao, Zhonglong; Liu, Bingbing; Cui, Tian

2016-01-01

High-pressure polymorphism and phase transitions have wide ranging consequences on the basic properties of ammonium nitrate. However, the phase diagram of ammonium nitrate at high pressure and high temperature is still under debate. This study systematically investigates the phase transitions and structural properties of ammonium nitrate at a pressure range of 5–60 GPa and temperature range of 250–400 K by ab initio molecular dynamics simulations. Two new phases are identified: one corresponds to the experimentally observed phase IV’ and the other is named AN-X. Simultaneously, the lattice strains play a significant role in the formation and stabilization of phase IV’, providing a reasonable explanation for experimental observation of phase IV-IV’ transition which only appears under nonhydrostatic pressure. In addition, 12 O atoms neighboring the NH (N atom in ammonium cation) atom are selected as reference system to clearly display the tanglesome rotation of ammonium cation. PMID:26754622

Modeling a color-rendering operator for high dynamic range images using a cone-response function

NASA Astrophysics Data System (ADS)

Choi, Ho-Hyoung; Kim, Gi-Seok; Yun, Byoung-Ju

2015-09-01

Tone-mapping operators are the typical algorithms designed to produce visibility and the overall impression of brightness, contrast, and color of high dynamic range (HDR) images on low dynamic range (LDR) display devices. Although several new tone-mapping operators have been proposed in recent years, the results of these operators have not matched those of the psychophysical experiments based on the human visual system. A color-rendering model that is a combination of tone-mapping and cone-response functions using an XYZ tristimulus color space is presented. In the proposed method, the tone-mapping operator produces visibility and the overall impression of brightness, contrast, and color in HDR images when mapped onto relatively LDR devices. The tone-mapping resultant image is obtained using chromatic and achromatic colors to avoid well-known color distortions shown in the conventional methods. The resulting image is then processed with a cone-response function wherein emphasis is placed on human visual perception (HVP). The proposed method covers the mismatch between the actual scene and the rendered image based on HVP. The experimental results show that the proposed method yields an improved color-rendering performance compared to conventional methods.

Direct Integration of Dynamic Emissive Displays into Knitted Fabric Structures

NASA Astrophysics Data System (ADS)

Bellingham, Alyssa

Smart textiles are revolutionizing the textile industry by combining technology into fabric to give clothing new abilities including communication, transformation, and energy conduction. The advent of electroluminescent fibers, which emit light in response to an applied electric field, has opened the door for fabric-integrated emissive displays in textiles. This thesis focuses on the development of a flexible and scalable emissive fabric display with individually addressable pixels disposed within a fabric matrix. The pixels are formed in areas where a fiber supporting the dielectric and phosphor layers of an electroluminescent structure contacts a conductive surface. This conductive surface can be an external conductive fiber, yarn or wire, or a translucent conductive material layer deposited at set points along the electroluminescent fibers. Different contacting methods are introduced and the different ways the EL yarns can be incorporated into the knitted fabric are discussed. EL fibers were fabricated using a single yarn coating system with a custom, adjustable 3D printed slot die coater for even distribution of material onto the supporting fiber substrates. These fibers are mechanically characterized inside of and outside of a knitted fabric matrix to determine their potential for various applications, including wearables. A 4-pixel dynamic emissive display prototype is fabricated and characterized. This is the first demonstration of an all-knit emissive display with individually controllable pixels. The prototype is composed of a grid of fibers supporting the dielectric and phosphor layers of an electroluminescent (EL) device structure, called EL fibers, and conductive fibers acting as the top electrode. This grid is integrated into a biaxial weft knit structure where the EL fibers make up the rows and conductive fibers make up the columns of the reinforcement yarns inside the supporting weft knit. The pixels exist as individual segments of electroluminescence that occur where the conductive fibers contact the EL fibers. A passive matrix addressing scheme was used to apply a voltage to each pixel individually, creating a display capable of dynamically communicating information. Optical measurements of the intensity and color of emitted light were used to quantify the performance of the display and compare it to state-of-the-art display technologies. The charge-voltage (Q-V) electrical characterization technique is used to gain information about the ACPEL fiber device operation, and mechanical tests were performed to determine the effect everyday wear and tear would have on the performance of the display. The presented textile display structure and method of producing fibers with individual sections of electroluminescence addresses the shortcomings in existing textile display technology and provides a route to directly integrated communicative textiles for applications ranging from biomedical research and monitoring to fashion. An extensive discussion of the materials and methods of production needed to scale this textile display technology and incorporate it into wearable applications is presented.

Dynamic stiffness of chemically and physically ageing rubber vibration isolators in the audible frequency range: Part 2—waveguide solution

NASA Astrophysics Data System (ADS)

Kari, Leif

2017-09-01

The dynamic stiffness of a chemically and physically ageing rubber vibration isolator in the audible frequency range is modelled as a function of ageing temperature, ageing time, actual temperature, time, frequency and isolator dimension. In particular, the dynamic stiffness for an axially symmetric, homogeneously aged rubber vibration isolator is derived by waveguides where the eigenmodes given by the dispersion relation for an infinite cylinder satisfying traction free radial surface boundary condition are matched to satisfy the displacement boundary conditions at the lateral surface ends of the finite rubber cylinder. The constitutive equations are derived in a companion paper (Part 1). The dynamic stiffness is calculated over the whole audible frequency range 20-20,000 Hz at several physical ageing times for a temperature history starting at thermodynamic equilibrium at +25°C and exposed by a sudden temperature step down to -60°C and at several chemical ageing times at temperature +25°C with simultaneous molecular network scission and reformation. The dynamic stiffness results are displaying a strong frequency dependence at a short physical ageing time, showing stiffness magnitude peaks and troughs, and a strong physical ageing time dependence, showing a large stiffness magnitude increase with the increased physical ageing time, while the peaks and troughs are smoothed out. Likewise, stiffness magnitude peaks and troughs are frequency-shifted with increased chemical ageing time. The developed model is possible to apply for dynamic stiffness prediction of rubber vibration isolator over a broad audible frequency range under realistic environmental condition of chemical ageing, mainly attributed to oxygen exposure from outside and of physical ageing, primarily perceived at low-temperature steps.

Long Range Plan for Embedded Computer Systems Support. Volume II

DTIC Science & Technology

1981-10-01

interface (pilot displays and controls plus visual system), and data collection (CMAC data, bus data and simulation data). Non-real time functions include...unless adequate upfront planning is implemented, the command will be controlled by the dynamics rather than controll - ing them. The upfront planning should...or should they be called manually? What amount and type of data should the various tools pass between each other? Under what conditions and controls

Sustaining Pinus flexilis ecosystems of the southern Rocky Mountains (USA) in the presence of Cronartium ribicola and Dendroctonus ponderosae in a changing climate

Treesearch

Anna W. Schoettle; Richard A. Sniezko; Kelly S. Burns

2009-01-01

Limber pine, Pinus flexilis James, is characterized by a patchy distribution that displays metapopulation dynamics and spans a broad latitudinal and elevational range in North America (Webster and Johnson 2000). In the southern Rocky Mountains limber pine grows from below the forest-grassland ecotone up to the forest-alpine ecotone, from ~1600 m above sea level in the...

Hard copies for digital medical images: an overview

NASA Astrophysics Data System (ADS)

Blume, Hartwig R.; Muka, Edward

1995-04-01

This paper is a condensed version of an invited overview on the technology of film hard-copies used in radiology. Because the overview was given to an essentially nonmedical audience, the reliance on film hard-copies in radiology is outlined in greater detail. The overview is concerned with laser image recorders generating monochrome prints on silver-halide films. The basic components of laser image recorders are sketched. The paper concentrates on the physical parameters - characteristic function, dynamic range, digitization resolution, modulation transfer function, and noise power spectrum - which define image quality and information transfer capability of the printed image. A preliminary approach is presented to compare the printed image quality with noise in the acquired image as well as with the noise of state-of- the-art cathode-ray-tube display systems. High-performance laser-image- recorder/silver-halide-film/light-box systems are well capable of reproducing acquired radiologic information. Most recently development was begun toward a display function standard for soft-copy display systems to facilitate similarity of image presentation between different soft-copy displays as well as between soft- and hard-copy displays. The standard display function is based on perceptional linearization. The standard is briefly reviewed to encourage the printer industry to adopt it, too.

DMS message design workshops.

DOT National Transportation Integrated Search

2009-03-01

This report summarizes the training conducted statewide regarding the design and display of messages on : dynamic message signs. The training is based on the Dynamic Message Sign Message Design and Display : Manual (0-4023-P3). Researchers developed ...

IViPP: A Tool for Visualization in Particle Physics

NASA Astrophysics Data System (ADS)

Tran, Hieu; Skiba, Elizabeth; Baldwin, Doug

2011-10-01

Experiments and simulations in physics generate a lot of data; visualization is helpful to prepare that data for analysis. IViPP (Interactive Visualizations in Particle Physics) is an interactive computer program that visualizes results of particle physics simulations or experiments. IViPP can handle data from different simulators, such as SRIM or MCNP. It can display relevant geometry and measured scalar data; it can do simple selection from the visualized data. In order to be an effective visualization tool, IViPP must have a software architecture that can flexibly adapt to new data sources and display styles. It must be able to display complicated geometry and measured data with a high dynamic range. We therefore organize it in a highly modular structure, we develop libraries to describe geometry algorithmically, use rendering algorithms running on the powerful GPU to display 3-D geometry at interactive rates, and we represent scalar values in a visual form of scientific notation that shows both mantissa and exponent. This work was supported in part by the US Department of Energy through the Laboratory for Laser Energetics (LLE), with special thanks to Craig Sangster at LLE.

Evaluation of image quality

NASA Technical Reports Server (NTRS)

Pavel, M.

1993-01-01

This presentation outlines in viewgraph format a general approach to the evaluation of display system quality for aviation applications. This approach is based on the assumption that it is possible to develop a model of the display which captures most of the significant properties of the display. The display characteristics should include spatial and temporal resolution, intensity quantizing effects, spatial sampling, delays, etc. The model must be sufficiently well specified to permit generation of stimuli that simulate the output of the display system. The first step in the evaluation of display quality is an analysis of the tasks to be performed using the display. Thus, for example, if a display is used by a pilot during a final approach, the aesthetic aspects of the display may be less relevant than its dynamic characteristics. The opposite task requirements may apply to imaging systems used for displaying navigation charts. Thus, display quality is defined with regard to one or more tasks. Given a set of relevant tasks, there are many ways to approach display evaluation. The range of evaluation approaches includes visual inspection, rapid evaluation, part-task simulation, and full mission simulation. The work described is focused on two complementary approaches to rapid evaluation. The first approach is based on a model of the human visual system. A model of the human visual system is used to predict the performance of the selected tasks. The model-based evaluation approach permits very rapid and inexpensive evaluation of various design decisions. The second rapid evaluation approach employs specifically designed critical tests that embody many important characteristics of actual tasks. These are used in situations where a validated model is not available. These rapid evaluation tests are being implemented in a workstation environment.

Evaluating the Effectiveness of Dynamic Speed Display Signs

DOT National Transportation Integrated Search

2012-09-01

This study investigates the impact of dynamic speed display signs (DSDSs) on drivers speed-related : behavior. A survey questionnaire regarding attitudes and reactions to DSDSs on different road : classes was distributed to Maryland drivers of dif...

Stabilization of Model Membrane Systems by Disaccharides. Quasielastic Neutron Scattering Experiments and Atomistic Simulations

NASA Astrophysics Data System (ADS)

Doxastakis, Emmanouil; Garcia Sakai, Victoria; Ohtake, Satoshi; Maranas, Janna K.; de Pablo, Juan J.

2006-03-01

Trehalose, a disaccharide of glucose, is often used for the stabilization of cell membranes in the absence of water. This work studies the effects of trehalose on model membrane systems as they undergo a melting transition using a combination of experimental methods and atomistic molecular simulations. Quasielastic neutron scattering experiments on selectively deuterated samples provide the incoherent dynamic structure over a wide time range. Elastic scans probing the lipid tail dynamics display clear evidence of a main melting transition that is significantly lowered in the presence of trehalose. Lipid headgroup mobility is considerably restricted at high temperatures and directly associated with the dynamics of the sugar in the mixture. Molecular simulations provide a detailed overview of the dynamics and their spatial and time dependence. The combined simulation and experimental methodology offers a unique, molecular view of the physics of systems commonly employed in cryopreservation and lyophilization processes.

Quantitative imaging of heterogeneous dynamics in drying and aging paints

PubMed Central

van der Kooij, Hanne M.; Fokkink, Remco; van der Gucht, Jasper; Sprakel, Joris

2016-01-01

Drying and aging paint dispersions display a wealth of complex phenomena that make their study fascinating yet challenging. To meet the growing demand for sustainable, high-quality paints, it is essential to unravel the microscopic mechanisms underlying these phenomena. Visualising the governing dynamics is, however, intrinsically difficult because the dynamics are typically heterogeneous and span a wide range of time scales. Moreover, the high turbidity of paints precludes conventional imaging techniques from reaching deep inside the paint. To address these challenges, we apply a scattering technique, Laser Speckle Imaging, as a versatile and quantitative tool to elucidate the internal dynamics, with microscopic resolution and spanning seven decades of time. We present a toolbox of data analysis and image processing methods that allows a tailored investigation of virtually any turbid dispersion, regardless of the geometry and substrate. Using these tools we watch a variety of paints dry and age with unprecedented detail. PMID:27682840

Static, dynamic and electronic properties of expanded fluid mercury in the metal-nonmetal transition range. An ab initio study.

PubMed

Calderín, L; González, L E; González, D J

2011-09-21

Fluid Hg undergoes a metal-nonmetal (M-NM) transition when expanded toward a density of around 9 g cm(-3). We have performed ab initio molecular dynamics simulations for several thermodynamic states around the M-NM transition range and the associated static, dynamic and electronic properties have been analyzed. The calculated static structure shows a good agreement with the available experimental data. It is found that the volume expansion decreases the number of nearest neighbors from 10 (near the triple point) to around 8 at the M-NM transition region. Moreover, these neighbors are arranged into two subshells and the decrease in the number of neighbors occurs in the inner subshell. The calculated dynamic structure factors agree fairly well with their experimental counterparts obtained by inelastic x-ray scattering experiments, which display inelastic side peaks. The derived dispersion relation exhibits some positive dispersion for all the states, although its value around the M-NM transition region is not as marked as suggested by the experiment. We have also calculated the electronic density of states, which shows the appearance of a gap at a density of around 8.3 g cm(-3).

Pathway concepts experiment for head-down synthetic vision displays

NASA Astrophysics Data System (ADS)

Prinzel, Lawrence J., III; Arthur, Jarvis J., III; Kramer, Lynda J.; Bailey, Randall E.

2004-08-01

Eight 757 commercial airline captains flew 22 approaches using the Reno Sparks 16R Visual Arrival under simulated Category I conditions. Approaches were flown using a head-down synthetic vision display to evaluate four tunnel ("minimal", "box", "dynamic pathway", "dynamic crow's feet") and three guidance ("ball", "tadpole", "follow-me aircraft") concepts and compare their efficacy to a baseline condition (i.e., no tunnel, ball guidance). The results showed that the tunnel concepts significantly improved pilot performance and situation awareness and lowered workload compared to the baseline condition. The dynamic crow's feet tunnel and follow-me aircraft guidance concepts were found to be the best candidates for future synthetic vision head-down displays. These results are discussed with implications for synthetic vision display design and future research.

Displaying R spatial statistics on Google dynamic maps with web applications created by Rwui

PubMed Central

2012-01-01

Background The R project includes a large variety of packages designed for spatial statistics. Google dynamic maps provide web based access to global maps and satellite imagery. We describe a method for displaying directly the spatial output from an R script on to a Google dynamic map. Methods This is achieved by creating a Java based web application which runs the R script and then displays the results on the dynamic map. In order to make this method easy to implement by those unfamiliar with programming Java based web applications, we have added the method to the options available in the R Web User Interface (Rwui) application. Rwui is an established web application for creating web applications for running R scripts. A feature of Rwui is that all the code for the web application being created is generated automatically so that someone with no knowledge of web programming can make a fully functional web application for running an R script in a matter of minutes. Results Rwui can now be used to create web applications that will display the results from an R script on a Google dynamic map. Results may be displayed as discrete markers and/or as continuous overlays. In addition, users of the web application may select regions of interest on the dynamic map with mouse clicks and the coordinates of the region of interest will automatically be made available for use by the R script. Conclusions This method of displaying R output on dynamic maps is designed to be of use in a number of areas. Firstly it allows statisticians, working in R and developing methods in spatial statistics, to easily visualise the results of applying their methods to real world data. Secondly, it allows researchers who are using R to study health geographics data, to display their results directly onto dynamic maps. Thirdly, by creating a web application for running an R script, a statistician can enable users entirely unfamiliar with R to run R coded statistical analyses of health geographics data. Fourthly, we envisage an educational role for such applications. PMID:22998945

Displaying R spatial statistics on Google dynamic maps with web applications created by Rwui.

PubMed

Newton, Richard; Deonarine, Andrew; Wernisch, Lorenz

2012-09-24

The R project includes a large variety of packages designed for spatial statistics. Google dynamic maps provide web based access to global maps and satellite imagery. We describe a method for displaying directly the spatial output from an R script on to a Google dynamic map. This is achieved by creating a Java based web application which runs the R script and then displays the results on the dynamic map. In order to make this method easy to implement by those unfamiliar with programming Java based web applications, we have added the method to the options available in the R Web User Interface (Rwui) application. Rwui is an established web application for creating web applications for running R scripts. A feature of Rwui is that all the code for the web application being created is generated automatically so that someone with no knowledge of web programming can make a fully functional web application for running an R script in a matter of minutes. Rwui can now be used to create web applications that will display the results from an R script on a Google dynamic map. Results may be displayed as discrete markers and/or as continuous overlays. In addition, users of the web application may select regions of interest on the dynamic map with mouse clicks and the coordinates of the region of interest will automatically be made available for use by the R script. This method of displaying R output on dynamic maps is designed to be of use in a number of areas. Firstly it allows statisticians, working in R and developing methods in spatial statistics, to easily visualise the results of applying their methods to real world data. Secondly, it allows researchers who are using R to study health geographics data, to display their results directly onto dynamic maps. Thirdly, by creating a web application for running an R script, a statistician can enable users entirely unfamiliar with R to run R coded statistical analyses of health geographics data. Fourthly, we envisage an educational role for such applications.

Three-dimensional (3D) GIS-based coastline change analysis and display using LIDAR series data

NASA Astrophysics Data System (ADS)

Zhou, G.

This paper presents a method to visualize and analyze topography and topographic changes on coastline area. The study area, Assantage Island Nation Seashore (AINS), is located along a 37-mile stretch of Assateague Island National Seashore in Eastern Shore, VA. The DEMS data sets from 1996 through 2000 for various time intervals, e.g., year-to-year, season-to-season, date-to-date, and a four year (1996-2000) are created. The spatial patterns and volumetric amounts of erosion and deposition of each part on a cell-by-cell basis were calculated. A 3D dynamic display system using ArcView Avenue for visualizing dynamic coastal landforms has been developed. The system was developed into five functional modules: Dynamic Display, Analysis, Chart analysis, Output, and Help. The Display module includes five types of displays: Shoreline display, Shore Topographic Profile, Shore Erosion Display, Surface TIN Display, and 3D Scene Display. Visualized data include rectified and co-registered multispectral Landsat digital image and NOAA/NASA ATM LIDAR data. The system is demonstrated using multitemporal digital satellite and LIDAR data for displaying changes on the Assateague Island National Seashore, Virginia. The analyzed results demonstrated that a further understanding to the study and comparison of the complex morphological changes that occur naturally or human-induced on barrier islands is required.

Knob manager (KM) operators guide

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

NONE

1993-10-08

KM, Knob Manager, is a tool which enables the user to use the SUNDIALS knob box to adjust the settings of the control system. The followings are some features of KM: dynamic knob assignments with the user friendly interface; user-defined gain for individual knob; graphical displays for operating range and status of each process variable is assigned; backup and restore one or multiple process variable; save current settings to a file and recall the settings from that file in future.

Dynamic beam steering at submm- and mm-wave frequencies using an optically controlled lens antenna

NASA Astrophysics Data System (ADS)

Gallacher, T. F.; Søndenâ, R.; Robertson, D. A.; Smith, G. M.

2013-05-01

We present details of our work which has been focused on improving the efficiency and scan rate of the photo-injected Fresnel zone plate antenna (piFZPA) technique which utilizes commercially available visible display technologies. This approach presents a viable low-cost solution for non-mechanical beam steering, suitable for many applications at (sub) mm-wave frequencies that require rapid beam steering capabilities in order to meet their technological goals, such as imaging, surveillance, and remote sensing. This method has the advantage of being comparatively low-cost, is based on a simple and flexible architecture, enabling rapid and precise arbitrary beam forming, and which is scalable to higher frame-rates and higher submm-wave frequencies. We discuss the various optimization stages of a range of piFZPA designs that implement fast visible projection displays, enabling up to 30,000 beams per second. We also outline the suitability of this technology across mm-wave and submm-wave frequencies as a low-cost and simple solution for dynamic optoelectronic beam steering.

Effects of controlled element dynamics on human feedforward behavior in ramp-tracking tasks.

PubMed

Laurense, Vincent A; Pool, Daan M; Damveld, Herman J; van Paassen, Marinus René M; Mulder, Max

2015-02-01

In real-life manual control tasks, human controllers are often required to follow a visible and predictable reference signal, enabling them to use feedforward control actions in conjunction with feedback actions that compensate for errors. Little is known about human control behavior in these situations. This paper investigates how humans adapt their feedforward control dynamics to the controlled element dynamics in a combined ramp-tracking and disturbance-rejection task. A human-in-the-loop experiment is performed with a pursuit display and vehicle-like controlled elements, ranging from a single integrator through second-order systems with a break frequency at either 3, 2, or 1 rad/s, to a double integrator. Because the potential benefits of feedforward control increase with steeper ramp segments in the target signal, three steepness levels are tested to investigate their possible effect on feedforward control with the various controlled elements. Analyses with four novel models of the operator, fitted to time-domain data, reveal feedforward control for all tested controlled elements and both (nonzero) tested levels of ramp steepness. For the range of controlled element dynamics investigated, it is found that humans adapt to these dynamics in their feedforward response, with a close to perfect inversion of the controlled element dynamics. No significant effects of ramp steepness on the feedforward model parameters are found.

Scaling Behavior in Mitochondrial Redox Fluctuations

PubMed Central

Ramanujan, V. Krishnan; Biener, Gabriel; Herman, Brian A.

2006-01-01

Scale-invariant long-range correlations have been reported in fluctuations of time-series signals originating from diverse processes such as heart beat dynamics, earthquakes, and stock market data. The common denominator of these apparently different processes is a highly nonlinear dynamics with competing forces and distinct feedback species. We report for the first time an experimental evidence for scaling behavior in NAD(P)H signal fluctuations in isolated mitochondria and intact cells isolated from the liver of a young (5-month-old) mouse. Time-series data were collected by two-photon imaging of mitochondrial NAD(P)H fluorescence and signal fluctuations were quantitatively analyzed for statistical correlations by detrended fluctuation analysis and spectral power analysis. Redox [NAD(P)H / NAD(P)+] fluctuations in isolated mitochondria and intact liver cells were found to display nonrandom, long-range correlations. These correlations are interpreted as arising due to the regulatory dynamics operative in Krebs' cycle enzyme network and electron transport chain in the mitochondria. This finding may provide a novel basis for understanding similar regulatory networks that govern the nonequilibrium properties of living cells. PMID:16565066

Thermal fluctuations and elastic relaxation in the compressed exponential dynamics of colloidal gels

NASA Astrophysics Data System (ADS)

Bouzid, Mehdi; Colombo, Jader; Del Gado, Emanuela

Colloidal gels belong to the class of amorphous systems, they are disordered elastic solids that can form at very low volume fraction, via aggregation into a rich variety of networks. They exhibit a slow relaxation process in the aging regime similar to the glassy dynamics. A wide range of experiments on colloidal gels show unusual compressed exponential of the relaxation dynamical properties. We use molecular dynamics simulation to investigate how the dynamic change with the age of the system. Upon breaking and reorganization of the network structure, the system may display stretched or compressed exponential relaxation. We show that the transition between these two regimes is associated to the interplay between thermally activated rearrangements and the elastic relaxation of internal stresses. In particular, ballistic-like displacements emerge from the non local relaxation of internal stresses mediated by a series of ''micro-collapses''. When thermal fluctuations dominate, the gel restructuring involves instead more homogeneous displacements across the heterogeneous gel network, leading to a stretched exponential type of relaxation.

Edge Singularities and Quasilong-Range Order in Nonequilibrium Steady States.

PubMed

De Nardis, Jacopo; Panfil, Miłosz

2018-05-25

The singularities of the dynamical response function are one of the most remarkable effects in many-body interacting systems. However in one dimension these divergences only exist strictly at zero temperature, making their observation very difficult in most cold atomic experimental settings. Moreover the presence of a finite temperature destroys another feature of one-dimensional quantum liquids: the real space quasilong-range order in which the spatial correlation functions exhibit power-law decay. We consider a nonequilibrium protocol where two interacting Bose gases are prepared either at different temperatures or chemical potentials and then joined. We show that the nonequilibrium steady state emerging at large times around the junction displays edge singularities in the response function and quasilong-range order.

Edge Singularities and Quasilong-Range Order in Nonequilibrium Steady States

NASA Astrophysics Data System (ADS)

De Nardis, Jacopo; Panfil, Miłosz

2018-05-01

The singularities of the dynamical response function are one of the most remarkable effects in many-body interacting systems. However in one dimension these divergences only exist strictly at zero temperature, making their observation very difficult in most cold atomic experimental settings. Moreover the presence of a finite temperature destroys another feature of one-dimensional quantum liquids: the real space quasilong-range order in which the spatial correlation functions exhibit power-law decay. We consider a nonequilibrium protocol where two interacting Bose gases are prepared either at different temperatures or chemical potentials and then joined. We show that the nonequilibrium steady state emerging at large times around the junction displays edge singularities in the response function and quasilong-range order.

OLED microdisplay design and materials

NASA Astrophysics Data System (ADS)

Wacyk, Ihor; Prache, Olivier; Ali, Tariq; Khayrullin, Ilyas; Ghosh, Amalkumar

2010-04-01

AMOLED microdisplays from eMagin Corporation are finding growing acceptance within the military display market as a result of their excellent power efficiency, wide operating temperature range, small size and weight, good system flexibility, and ease of use. The latest designs have also demonstrated improved optical performance including better uniformity, contrast, MTF, and color gamut. eMagin's largest format display is currently the SXGA design, which includes features such as a 30-bit wide RGB digital interface, automatic luminance regulation from -45 to +70°C, variable gamma control, and a dynamic range exceeding 50:000 to 1. This paper will highlight the benefits of eMagin's latest microdisplay designs and review the roadmap for next generation devices. The ongoing development of reduced size pixels and larger format displays (up to WUXGA) as well as new OLED device architecture (e.g. high-brightness yellow) will be discussed. Approaches being explored for improved performance in next generation designs such as lowpower serial interfaces, high frame rate operation, and new operational modes for reduction of motion artifacts will also be described. These developments should continue to enhance the appeal of AMOLED microdisplays for a broad spectrum of near-to-the-eye applications such as night vision, simulation and training, situational awareness, augmented reality, medical imaging, and mobile video entertainment and gaming.

Sensitive detection of maltose and glucose based on dual enzyme-displayed bacteria electrochemical biosensor.

PubMed

Liu, Aihua; Lang, Qiaolin; Liang, Bo; Shi, Jianguo

2017-01-15

Glucoamylase-displayed bacteria (GA-bacteria) and glucose dehydrogenase-displayed bacteria (GDH-bacteria) were co-immobilized on multi-walled carbon nanotubes (MWNTs) modified glassy carbon electrode (GCE) to construct GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor. The biosensor was developed by optimizing the loading amount and the ratio of GA-bacteria to GDH-bacteria. The as-prepared biosensor exhibited a wide dynamic range of 0.2-10mM and a low detection limit of 0.1mM maltose (S/N=3). The biosensor also had a linear response to glucose in the range of 0.1-2.0mM and a low detection limit of 0.04mM glucose (S/N=3). Interestingly, at the same concentration, glucose was 3.75-fold sensitive than that of maltose at the proposed biosensor. No interferences were observed for other possible mono- and disaccharides. The biosensor also demonstrated good long-term storage stability and repeatability. Further, using both GDH-bacteria/MWNTs/GCE biosensor and GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor, glucose and maltose in real samples can be detected. Therefore, the proposed biosensor is capable of monitoring the food manufacturing and fermentation process. Copyright © 2016 Elsevier B.V. All rights reserved.

Pathway Concepts Experiment for Head-Down Synthetic Vision Displays

NASA Technical Reports Server (NTRS)

Prinzel, Lawrence J., III; Arthur, Jarvis J., III; Kramer, Lynda J.; Bailey, Randall E.

2004-01-01

Eight 757 commercial airline captains flew 22 approaches using the Reno Sparks 16R Visual Arrival under simulated Category I conditions. Approaches were flown using a head-down synthetic vision display to evaluate four tunnel ("minimal", "box", "dynamic pathway", "dynamic crow s feet") and three guidance ("ball", "tadpole", "follow-me aircraft") concepts and compare their efficacy to a baseline condition (i.e., no tunnel, ball guidance). The results showed that the tunnel concepts significantly improved pilot performance and situation awareness and lowered workload compared to the baseline condition. The dynamic crow s feet tunnel and follow-me aircraft guidance concepts were found to be the best candidates for future synthetic vision head-down displays. These results are discussed with implications for synthetic vision display design and future research.

Image Geometric Corrections for a New EMCCD-based Dual Modular X-ray Imager

PubMed Central

Qu, Bin; Huang, Ying; Wang, Weiyuan; Cartwright, Alexander N.; Titus, Albert H.; Bednarek, Daniel R.; Rudin, Stephen

2012-01-01

An EMCCD-based dual modular x-ray imager was recently designed and developed from the component level, providing a high dynamic range of 53 dB and an effective pixel size of 26 μm for angiography and fluoroscopy. The unique 2×1 array design efficiently increased the clinical field of view, and also can be readily expanded to an M×N array implementation. Due to the alignment mismatches between the EMCCD sensors and the fiber optic tapers in each module, the output images or video sequences result in a misaligned 2048×1024 digital display if uncorrected. In this paper, we present a method for correcting display registration using a custom-designed two layer printed circuit board. This board was designed with grid lines to serve as the calibration pattern, and provides an accurate reference and sufficient contrast to enable proper display registration. Results show an accurate and fine stitching of the two outputs from the two modules. PMID:22254882

The relationship between ambient illumination and psychological factors in viewing of display Images

NASA Astrophysics Data System (ADS)

Iwanami, Takuya; Kikuchi, Ayano; Kaneko, Takashi; Hirai, Keita; Yano, Natsumi; Nakaguchi, Toshiya; Tsumura, Norimichi; Yoshida, Yasuhiro; Miyake, Yoichi

2009-01-01

In this paper, we have clarified the relationship between ambient illumination and psychological factors in viewing of display images. Psychological factors were obtained by the factor analysis with the results of the semantic differential (SD) method. In the psychological experiments, subjects evaluated the impressions of displayed images with changing ambient illuminating conditions. The illumination conditions were controlled by a fluorescent ceiling light and a color LED illumination which was located behind the display. We experimented under two kinds of conditions. One was the experiment with changing brightness of the ambient illumination. The other was the experiment with changing the colors of the background illumination. In the results of the experiment, two factors "realistic sensation, dynamism" and "comfortable," were extracted under different brightness of the ambient illumination of the display surroundings. It was shown that the "comfortable" was improved by the brightness of display surroundings. On the other hand, when the illumination color of surroundings was changed, three factors "comfortable," "realistic sensation, dynamism" and "activity" were extracted. It was also shown that the value of "comfortable" and "realistic sensation, dynamism" increased when the display surroundings were illuminated by the average color of the image contents.

Method and apparatus for reflection mode imaging

NASA Technical Reports Server (NTRS)

Heyser, Richard C. (Inventor); Rooney, James A. (Inventor)

1989-01-01

A volume is scanned with a raster scan about a center of rotation using a transmitter/receiver at a selected range while gating a range window on the receiver with a selected range differential. The received signals are then demodulated to obtain signals representative of a property within the volume being scanned such as the density of a tumor. The range is varied until the entire volume has been scanned at all ranges to be displayed. An imaging display is synchronously scanned together with the raster scan to display variations of the property on the display. A second transmitter/receiver with associated equipment may be offset from the first and variations displayed from each of the transmitter/receivers on its separate display. The displays may then be combined stereoscopically to provide a three-dimensional image representative of variations of the property.

Statistical mechanical approach to secondary processes and structural relaxation in glasses and glass formers: a leading model to describe the onset of Johari-Goldstein processes and their relationship with fully cooperative processes.

PubMed

Crisanti, A; Leuzzi, L; Paoluzzi, M

2011-09-01

The interrelation of dynamic processes active on separated time-scales in glasses and viscous liquids is investigated using a model displaying two time-scale bifurcations both between fast and secondary relaxation and between secondary and structural relaxation. The study of the dynamics allows for predictions on the system relaxation above the temperature of dynamic arrest in the mean-field approximation, that are compared with the outcomes of the equations of motion directly derived within the Mode Coupling Theory (MCT) for under-cooled viscous liquids. By varying the external thermodynamic parameters, a wide range of phenomenology can be represented, from a very clear separation of structural and secondary peak in the susceptibility loss to excess wing structures.

Parallel search for conjunctions with stimuli in apparent motion.

PubMed

Casco, C; Ganis, G

1999-01-01

A series of experiments was conducted to determine whether apparent motion tends to follow the similarity rule (i.e. is attribute-specific) and to investigate the underlying mechanism. Stimulus duration thresholds were measured during a two-alternative forced-choice task in which observers detected either the location or the motion direction of target groups defined by the conjunction of size and orientation. Target element positions were randomly chosen within a nominally defined rectangular subregion of the display (target region). The target region was presented either statically (followed by a 250 ms duration mask) or dynamically, displaced by a small distance (18 min of arc) from frame to frame. In the motion display, the position of both target and background elements was changed randomly from frame to frame within the respective areas to abolish spatial correspondence over time. Stimulus duration thresholds were lower in the motion than in the static task, indicating that target detection in the dynamic condition does not rely on the explicit identification of target elements in each static frame. Increasing the distractor-to-target ratio was found to reduce detectability in the static, but not in the motion task. This indicates that the perceptual segregation of the target is effortless and parallel with motion but not with static displays. The pattern of results holds regardless of the task or search paradigm employed. The detectability in the motion condition can be improved by increasing the number of frames and/or by reducing the width of the target area. Furthermore, parallel search in the dynamic condition can be conducted with both short-range and long-range motion stimuli. Finally, apparent motion of conjunctions is insufficient on its own to support location decision and is disrupted by random visual noise. Overall, these findings show that (i) the mechanism underlying apparent motion is attribute-specific; (ii) the motion system mediates temporal integration of feature conjunctions before they are identified by the static system; and (iii) target detectability in these stimuli relies upon a nonattentive, cooperative, directionally selective motion mechanism that responds to high-level attributes (conjunction of size and orientation).

New Evidence for Strategic Differences between Static and Dynamic Search Tasks: An Individual Observer Analysis of Eye Movements

PubMed Central

Dickinson, Christopher A.; Zelinsky, Gregory J.

2013-01-01

Two experiments are reported that further explore the processes underlying dynamic search. In Experiment 1, observers’ oculomotor behavior was monitored while they searched for a randomly oriented T among oriented L distractors under static and dynamic viewing conditions. Despite similar search slopes, eye movements were less frequent and more spatially constrained under dynamic viewing relative to static, with misses also increasing more with target eccentricity in the dynamic condition. These patterns suggest that dynamic search involves a form of sit-and-wait strategy in which search is restricted to a small group of items surrounding fixation. To evaluate this interpretation, we developed a computational model of a sit-and-wait process hypothesized to underlie dynamic search. In Experiment 2 we tested this model by varying fixation position in the display and found that display positions optimized for a sit-and-wait strategy resulted in higher d′ values relative to a less optimal location. We conclude that different strategies, and therefore underlying processes, are used to search static and dynamic displays. PMID:23372555

Performance characterization of a single bi-axial scanning MEMS mirror-based head-worn display

NASA Astrophysics Data System (ADS)

Liang, Minhua

2002-06-01

The NomadTM Personal Display System is a head-worn display (HWD) with a see-through, high-resolution, high-luminance display capability. It is based on a single bi-axial scanning MEMS mirror. In the Nomad HWD system, a red laser diode emits a beam of light that is scanned bi-axially by a single MEMS mirror. A diffractive beam diffuser and an ocular expand the beam to form a 12mm exit pupil for comfortable viewing. The Nomad display has an SVGA (800x600) resolution, 60Hz frame rate, 23-degree horizontal field of view (FOV) and 3:4 vertical to horizontal aspect ratio, a luminance of 800~900 foot-Lamberts, see-through capability, 30mm eye-relief distance, and 1-foot to infinity focusing adjustment. We have characterized the performance parameters, such as field of view, distortion, contrast ratio (4x4 black and white checker board), modulation depth, exit pupil size, eye relief distance, maximum luminance, dynamic range ratio (full-on-to-full-off ratio), dimming ratio, and luminance uniformity at image plane. The Class-1 eye-safety requirements per IEC 60825-1 Amendment 2 (CDRH Laser Notice No. 50) are analyzed and verified by experiments. The paper describes all of the testing methods and set-ups as well as the representative test results. The test results demonstrate that the Nomad display is an eye-safe display product with good image quality and good user ergonomics.

A high gain wide dynamic range transimpedance amplifier for optical receivers

NASA Astrophysics Data System (ADS)

Lianxi, Liu; Jiao, Zou; Yunfei, En; Shubin, Liu; Yue, Niu; Zhangming, Zhu; Yintang, Yang

2014-01-01

As the front-end preamplifiers in optical receivers, transimpedance amplifiers (TIAs) are commonly required to have a high gain and low input noise to amplify the weak and susceptible input signal. At the same time, the TIAs should possess a wide dynamic range (DR) to prevent the circuit from becoming saturated by high input currents. Based on the above, this paper presents a CMOS transimpedance amplifier with high gain and a wide DR for 2.5 Gbit/s communications. The TIA proposed consists of a three-stage cascade pull push inverter, an automatic gain control circuit, and a shunt transistor controlled by the resistive divider. The inductive-series peaking technique is used to further extend the bandwidth. The TIA proposed displays a maximum transimpedance gain of 88.3 dBΩ with the -3 dB bandwidth of 1.8 GHz, exhibits an input current dynamic range from 100 nA to 10 mA. The output voltage noise is less than 48.23 nV/√Hz within the -3 dB bandwidth. The circuit is fabricated using an SMIC 0.18 μm 1P6M RFCMOS process and dissipates a dc power of 9.4 mW with 1.8 V supply voltage.

Relative phase asynchrony and long-range correlation of long-term solar magnetic activity

NASA Astrophysics Data System (ADS)

Deng, Linhua

2017-07-01

Statistical signal processing is one of the most important tasks in a large amount of areas of scientific studies, such as astrophysics, geophysics, and space physics. Phase recurrence analysis and long-range persistence are the two dynamical structures of the underlying processes for the given natural phenomenon. Linear and nonlinear time series analysis approaches (cross-correlation analysis, cross-recurrence plot, wavelet coherent transform, and Hurst analysis) are combined to investigate the relative phase interconnection and long-range correlation between solar activity and geomagnetic activity for the time interval from 1932 January to 2017 January. The following prominent results are found: (1) geomagnetic activity lags behind sunspot numbers with a phase shift of 21 months, and they have a high level of asynchronous behavior; (2) their relative phase interconnections are in phase for the periodic scales during 8-16 years, but have a mixing behavior for the periodic belts below 8 years; (3) both sunspot numbers and geomagnetic activity can not be regarded as a stochastic phenomenon because their dynamical behaviors display a long-term correlation and a fractal nature. We believe that the presented conclusions could provide further information on understanding the dynamical coupling of solar dynamo process with geomagnetic activity variation, and the crucial role of solar and geomagnetic activity in the long-term climate change.

Complex Systems

PubMed Central

Goldberger, Ary L.

2006-01-01

Physiologic systems in health and disease display an extraordinary range of temporal behaviors and structural patterns that defy understanding based on linear constructs, reductionist strategies, and classical homeostasis. Application of concepts and computational tools derived from the contemporary study of complex systems, including nonlinear dynamics, fractals and “chaos theory,” is having an increasing impact on biology and medicine. This presentation provides a brief overview of an emerging area of biomedical research, including recent applications to cardiopulmonary medicine and chronic obstructive lung disease. PMID:16921107

Heterogeneous distributional responses to climate warming: evidence from rodents along a subtropical elevational gradient.

PubMed

Wen, Zhixin; Wu, Yi; Ge, Deyan; Cheng, Jilong; Chang, Yongbin; Yang, Zhisong; Xia, Lin; Yang, Qisen

2017-04-20

Understanding whether species' elevational range is shifting in response to directional changes in climate and whether there is a predictable pattern in that response is one of the major challenges in ecology. However, so far very little is known about the distributional responses of subtropical species to climate change, especially for small mammals. In this study, we examined the elevational range shifts at three range points (upper and lower range limits and abundance-weighted range centre) of rodents over a 30-year period (1986 to 2014-2015), in a subtropical forest of Southwest China. We also examined the influences of four ecological traits (body mass, habitat breadth, diet and daily activity pattern) on the upslope shifts in species' abundance-weighted range centres. Despite the warming trend between 1986 and 2015, the 11 rodent species in analysis displayed heterogeneous dynamics at each of the three range points. Species which have larger body sizes and narrower habitat breadths, show both diurnal and nocturnal activities and more specialized dietary requirements, are more likely to exhibit upslope shifts in abundance-weighted range centres. Species' distributional responses can be heterogeneous even though there are directional changes in climate. Our study indicates that climate-induced alleviation of competition and lag in response may potentially drive species' range shift, which may not conform to the expectation from climate change. Difference in traits can lead to different range dynamics. Our study also illustrates the merit of multi-faceted assessment in studying elevational range shifts.

Long-range correlations and fractal dynamics in C. elegans: Changes with aging and stress

NASA Astrophysics Data System (ADS)

Alves, Luiz G. A.; Winter, Peter B.; Ferreira, Leonardo N.; Brielmann, Renée M.; Morimoto, Richard I.; Amaral, Luís A. N.

2017-08-01

Reduced motor control is one of the most frequent features associated with aging and disease. Nonlinear and fractal analyses have proved to be useful in investigating human physiological alterations with age and disease. Similar findings have not been established for any of the model organisms typically studied by biologists, though. If the physiology of a simpler model organism displays the same characteristics, this fact would open a new research window on the control mechanisms that organisms use to regulate physiological processes during aging and stress. Here, we use a recently introduced animal-tracking technology to simultaneously follow tens of Caenorhabdits elegans for several hours and use tools from fractal physiology to quantitatively evaluate the effects of aging and temperature stress on nematode motility. Similar to human physiological signals, scaling analysis reveals long-range correlations in numerous motility variables, fractal properties in behavioral shifts, and fluctuation dynamics over a wide range of timescales. These properties change as a result of a superposition of age and stress-related adaptive mechanisms that regulate motility.

Single-layer HDR video coding with SDR backward compatibility

NASA Astrophysics Data System (ADS)

Lasserre, S.; François, E.; Le Léannec, F.; Touzé, D.

2016-09-01

The migration from High Definition (HD) TV to Ultra High Definition (UHD) is already underway. In addition to an increase of picture spatial resolution, UHD will bring more color and higher contrast by introducing Wide Color Gamut (WCG) and High Dynamic Range (HDR) video. As both Standard Dynamic Range (SDR) and HDR devices will coexist in the ecosystem, the transition from Standard Dynamic Range (SDR) to HDR will require distribution solutions supporting some level of backward compatibility. This paper presents a new HDR content distribution scheme, named SL-HDR1, using a single layer codec design and providing SDR compatibility. The solution is based on a pre-encoding HDR-to-SDR conversion, generating a backward compatible SDR video, with side dynamic metadata. The resulting SDR video is then compressed, distributed and decoded using standard-compliant decoders (e.g. HEVC Main 10 compliant). The decoded SDR video can be directly rendered on SDR displays without adaptation. Dynamic metadata of limited size are generated by the pre-processing and used to reconstruct the HDR signal from the decoded SDR video, using a post-processing that is the functional inverse of the pre-processing. Both HDR quality and artistic intent are preserved. Pre- and post-processing are applied independently per picture, do not involve any inter-pixel dependency, and are codec agnostic. Compression performance, and SDR quality are shown to be solidly improved compared to the non-backward and backward-compatible approaches, respectively using the Perceptual Quantization (PQ) and Hybrid Log Gamma (HLG) Opto-Electronic Transfer Functions (OETF).

Movements, Home Range and Site Fidelity of Snapper (Chrysophrys auratus) within a Temperate Marine Protected Area

PubMed Central

Harasti, David; Lee, Kate A.; Gallen, Christopher; Hughes, Julian M.; Stewart, John

2015-01-01

Understanding the movement dynamics of marine fish provides valuable information that can assist with species management, particularly regarding protection within marine protected areas (MPAs). We performed an acoustic tagging study implemented within the Port Stephens-Great Lakes Marine Park on the mid-north coast of New South Wales, Australia, to assess the movement patterns, home range and diel activity of snapper (Chrysophrys auratus; Sparidae); a species of significant recreational and commercial fishing importance in Australia. The study focused on C. auratus movements around Cabbage Tree Island, which is predominantly a no-take sanctuary zone (no fishing), with an array of acoustic stations deployed around the island and adjacent reefs and islands. Thirty C. auratus were tagged with internal acoustic tags in November 2010 with their movements recorded until September 2014. Both adult and juvenile C. auratus were observed to display strong site fidelity to Cabbage Tree Island with a mean 12-month residency index of 0.83 (range = 0 low to 1 high). Only three fish were detected on acoustic receivers away from Cabbage Tree Island, with one fish moving a considerable distance of ~ 290 kms over a short time frame (46 days). The longest period of residency recorded at the island was for three fish occurring regularly at the site for a period of 1249 days. Chrysophrys auratus displayed strong diurnal behaviour and detection frequency was significantly higher during the day than at night; however, there was no significant difference in detection frequency between different hours. This study demonstrates that even small-scale protected areas can benefit C. auratus during multiple life-history stages as it maintains a small home range and displays strong site fidelity over a period of 3 years. PMID:26544185

Prospective Memory and Task Interference in a Continuous Monitoring Dynamic Display Task

ERIC Educational Resources Information Center

Loft, Shayne; Remington, Roger W.

2010-01-01

Theories and methods from the prospective memory literature were used to anticipate how individuals would maintain and retrieve intentions in a continuous monitoring dynamic display task. Participants accepted aircraft into sectors and detected aircraft conflicts during an air traffic control simulation. They were sometimes required to substitute…

Trend Motif: A Graph Mining Approach for Analysis of Dynamic Complex Networks

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

Jin, R; McCallen, S; Almaas, E

2007-05-28

Complex networks have been used successfully in scientific disciplines ranging from sociology to microbiology to describe systems of interacting units. Until recently, studies of complex networks have mainly focused on their network topology. However, in many real world applications, the edges and vertices have associated attributes that are frequently represented as vertex or edge weights. Furthermore, these weights are often not static, instead changing with time and forming a time series. Hence, to fully understand the dynamics of the complex network, we have to consider both network topology and related time series data. In this work, we propose a motifmore » mining approach to identify trend motifs for such purposes. Simply stated, a trend motif describes a recurring subgraph where each of its vertices or edges displays similar dynamics over a userdefined period. Given this, each trend motif occurrence can help reveal significant events in a complex system; frequent trend motifs may aid in uncovering dynamic rules of change for the system, and the distribution of trend motifs may characterize the global dynamics of the system. Here, we have developed efficient mining algorithms to extract trend motifs. Our experimental validation using three disparate empirical datasets, ranging from the stock market, world trade, to a protein interaction network, has demonstrated the efficiency and effectiveness of our approach.« less

Research and test facilities

NASA Technical Reports Server (NTRS)

1993-01-01

A description is given of each of the following Langley research and test facilities: 0.3-Meter Transonic Cryogenic Tunnel, 7-by 10-Foot High Speed Tunnel, 8-Foot Transonic Pressure Tunnel, 13-Inch Magnetic Suspension & Balance System, 14-by 22-Foot Subsonic Tunnel, 16-Foot Transonic Tunnel, 16-by 24-Inch Water Tunnel, 20-Foot Vertical Spin Tunnel, 30-by 60-Foot Wind Tunnel, Advanced Civil Transport Simulator (ACTS), Advanced Technology Research Laboratory, Aerospace Controls Research Laboratory (ACRL), Aerothermal Loads Complex, Aircraft Landing Dynamics Facility (ALDF), Avionics Integration Research Laboratory, Basic Aerodynamics Research Tunnel (BART), Compact Range Test Facility, Differential Maneuvering Simulator (DMS), Enhanced/Synthetic Vision & Spatial Displays Laboratory, Experimental Test Range (ETR) Flight Research Facility, General Aviation Simulator (GAS), High Intensity Radiated Fields Facility, Human Engineering Methods Laboratory, Hypersonic Facilities Complex, Impact Dynamics Research Facility, Jet Noise Laboratory & Anechoic Jet Facility, Light Alloy Laboratory, Low Frequency Antenna Test Facility, Low Turbulence Pressure Tunnel, Mechanics of Metals Laboratory, National Transonic Facility (NTF), NDE Research Laboratory, Polymers & Composites Laboratory, Pyrotechnic Test Facility, Quiet Flow Facility, Robotics Facilities, Scientific Visualization System, Scramjet Test Complex, Space Materials Research Laboratory, Space Simulation & Environmental Test Complex, Structural Dynamics Research Laboratory, Structural Dynamics Test Beds, Structures & Materials Research Laboratory, Supersonic Low Disturbance Pilot Tunnel, Thermal Acoustic Fatigue Apparatus (TAFA), Transonic Dynamics Tunnel (TDT), Transport Systems Research Vehicle, Unitary Plan Wind Tunnel, and the Visual Motion Simulator (VMS).

Issues in symbol design for electronic displays of navigation information

DOT National Transportation Integrated Search

2004-10-24

An increasing number of electronic displays, ranging from small hand-held displays for general aviation to installed displays for air transport, are showing navigation information, such as symbols representing navigational aids. The wide range of dis...

Linear and nonlinear spectroscopy from quantum master equations.

PubMed

Fetherolf, Jonathan H; Berkelbach, Timothy C

2017-12-28

We investigate the accuracy of the second-order time-convolutionless (TCL2) quantum master equation for the calculation of linear and nonlinear spectroscopies of multichromophore systems. We show that even for systems with non-adiabatic coupling, the TCL2 master equation predicts linear absorption spectra that are accurate over an extremely broad range of parameters and well beyond what would be expected based on the perturbative nature of the approach; non-equilibrium population dynamics calculated with TCL2 for identical parameters are significantly less accurate. For third-order (two-dimensional) spectroscopy, the importance of population dynamics and the violation of the so-called quantum regression theorem degrade the accuracy of TCL2 dynamics. To correct these failures, we combine the TCL2 approach with a classical ensemble sampling of slow microscopic bath degrees of freedom, leading to an efficient hybrid quantum-classical scheme that displays excellent accuracy over a wide range of parameters. In the spectroscopic setting, the success of such a hybrid scheme can be understood through its separate treatment of homogeneous and inhomogeneous broadening. Importantly, the presented approach has the computational scaling of TCL2, with the modest addition of an embarrassingly parallel prefactor associated with ensemble sampling. The presented approach can be understood as a generalized inhomogeneous cumulant expansion technique, capable of treating multilevel systems with non-adiabatic dynamics.

Linear and nonlinear spectroscopy from quantum master equations

NASA Astrophysics Data System (ADS)

Fetherolf, Jonathan H.; Berkelbach, Timothy C.

2017-12-01

We investigate the accuracy of the second-order time-convolutionless (TCL2) quantum master equation for the calculation of linear and nonlinear spectroscopies of multichromophore systems. We show that even for systems with non-adiabatic coupling, the TCL2 master equation predicts linear absorption spectra that are accurate over an extremely broad range of parameters and well beyond what would be expected based on the perturbative nature of the approach; non-equilibrium population dynamics calculated with TCL2 for identical parameters are significantly less accurate. For third-order (two-dimensional) spectroscopy, the importance of population dynamics and the violation of the so-called quantum regression theorem degrade the accuracy of TCL2 dynamics. To correct these failures, we combine the TCL2 approach with a classical ensemble sampling of slow microscopic bath degrees of freedom, leading to an efficient hybrid quantum-classical scheme that displays excellent accuracy over a wide range of parameters. In the spectroscopic setting, the success of such a hybrid scheme can be understood through its separate treatment of homogeneous and inhomogeneous broadening. Importantly, the presented approach has the computational scaling of TCL2, with the modest addition of an embarrassingly parallel prefactor associated with ensemble sampling. The presented approach can be understood as a generalized inhomogeneous cumulant expansion technique, capable of treating multilevel systems with non-adiabatic dynamics.

Contrast Transmission In Medical Image Display

NASA Astrophysics Data System (ADS)

Pizer, Stephen M.; Zimmerman, John B.; Johnston, R. Eugene

1982-11-01

The display of medical images involves transforming recorded intensities such at CT numbers into perceivable intensities such as combinations of color and luminance. For the viewer to extract the most information about patterns of decreasing and increasing recorded intensity, the display designer must pay attention to three issues: 1) choice of display scale, including its discretization; 2) correction for variations in contrast sensitivity across the display scale due to the observer and the display device (producing an honest display); and 3) contrast enhancement based on the information in the recorded image and its importance, determined by viewing objectives. This paper will present concepts and approaches in all three of these areas. In choosing display scales three properties are important: sensitivity, associability, and naturalness of order. The unit of just noticeable difference (jnd) will be carefully defined. An observer experiment to measure the jnd values across a display scale will be specified. The overall sensitivity provided by a scale as measured in jnd's gives a measure of sensitivity called the perceived dynamic range (PDR). Methods for determining the PDR fran the aforementioned PDR values, and PDR's for various grey and pseudocolor scales will be presented. Methods of achieving sensitivity while retaining associability and naturalness of order with pseudocolor scales will be suggested. For any display device and scale it is useful to compensate for the device and observer by preceding the device with an intensity mapping (lookup table) chosen so that perceived intensity is linear with display-driving intensity. This mapping can be determined from the aforementioned jnd values. With a linearized display it is possible to standardize display devices so that the same image displayed on different devices or scales (e.g. video and hard copy) will be in sane sense perceptually equivalent. Furthermore, with a linearized display, it is possible to design contrast enhancement mappings that optimize the transmission of information from the recorded image to the display-driving signal with the assurance that this information will not then be lost by a -further nonlinear relation between display-driving and perceived intensity. It is suggested that optimal contrast enhancement mappings are adaptive to the local distribution of recorded intensities.

Optimal guidance for the space shuttle transition

NASA Technical Reports Server (NTRS)

Stengel, R. F.

1972-01-01

A guidance method for the space shuttle's transition from hypersonic entry to subsonic cruising flight is presented. The method evolves from a numerical trajectory optimization technique in which kinetic energy and total energy (per unit weight) replace velocity and time in the dynamic equations. This allows the open end-time problem to be transformed to one of fixed terminal energy. In its ultimate form, E-Guidance obtains energy balance (including dynamic-pressure-rate damping) and path length control by angle-of-attack modulation and cross-range control by roll angle modulation. The guidance functions also form the basis for a pilot display of instantaneous maneuver limits and destination. Numerical results illustrate the E-Guidance concept and the optimal trajectories on which it is based.

Designing Websites for Displaying Large Data Sets and Images on Multiple Platforms

NASA Astrophysics Data System (ADS)

Anderson, A.; Wolf, V. G.; Garron, J.; Kirschner, M.

2012-12-01

The desire to build websites to analyze and display ever increasing amounts of scientific data and images pushes for web site designs which utilize large displays, and to use the display area as efficiently as possible. Yet, scientists and users of their data are increasingly wishing to access these websites in the field and on mobile devices. This results in the need to develop websites that can support a wide range of devices and screen sizes, and to optimally use whatever display area is available. Historically, designers have addressed this issue by building two websites; one for mobile devices, and one for desktop environments, resulting in increased cost, duplicity of work, and longer development times. Recent advancements in web design technology and techniques have evolved which allow for the development of a single website that dynamically adjusts to the type of device being used to browse the website (smartphone, tablet, desktop). In addition they provide the opportunity to truly optimize whatever display area is available. HTML5 and CSS3 give web designers media query statements which allow design style sheets to be aware of the size of the display being used, and to format web content differently based upon the queried response. Web elements can be rendered in a different size, position, or even removed from the display entirely, based upon the size of the display area. Using HTML5/CSS3 media queries in this manner is referred to as "Responsive Web Design" (RWD). RWD in combination with technologies such as LESS and Twitter Bootstrap allow the web designer to build web sites which not only dynamically respond to the browser display size being used, but to do so in very controlled and intelligent ways, ensuring that good layout and graphic design principles are followed while doing so. At the University of Alaska Fairbanks, the Alaska Satellite Facility SAR Data Center (ASF) recently redesigned their popular Vertex application and converted it from a traditional, fixed-layout website into a RWD site built on HTML5, LESS and Twitter Bootstrap. Vertex is a data portal for remotely sensed imagery of the earth, offering Synthetic Aperture Radar (SAR) data products from the global ASF archive. By using Responsive Web Design, ASF is able to provide access to a massive collection of SAR imagery and allow the user to use mobile devices and desktops to maximum advantage. ASF's Vertex web site demonstrates that with increased interface flexibility, scientists, managers and users can increase their personal effectiveness by accessing data portals from their preferred device as their science dictates.

Selection dynamic of Escherichia coli host in M13 combinatorial peptide phage display libraries.

PubMed

Zanconato, Stefano; Minervini, Giovanni; Poli, Irene; De Lucrezia, Davide

2011-01-01

Phage display relies on an iterative cycle of selection and amplification of random combinatorial libraries to enrich the initial population of those peptides that satisfy a priori chosen criteria. The effectiveness of any phage display protocol depends directly on library amino acid sequence diversity and the strength of the selection procedure. In this study we monitored the dynamics of the selective pressure exerted by the host organism on a random peptide library in the absence of any additional selection pressure. The results indicate that sequence censorship exerted by Escherichia coli dramatically reduces library diversity and can significantly impair phage display effectiveness.

INFORM: An interactive data collection and display program with debugging capability

NASA Technical Reports Server (NTRS)

Cwynar, D. S.

1980-01-01

A computer program was developed to aid ASSEMBLY language programmers of mini and micro computers in solving the man machine communications problems that exist when scaled integers are involved. In addition to producing displays of quasi-steady state values, INFORM provides an interactive mode for debugging programs, making program patches, and modifying the displays. Auxiliary routines SAMPLE and DATAO add dynamic data acquisition and high speed dynamic display capability to the program. Programming information and flow charts to aid in implementing INFORM on various machines together with descriptions of all supportive software are provided. Program modifications to satisfy the individual user's needs are considered.

Formation and field-driven dynamics of nematic spheroids.

PubMed

Fu, Fred; Abukhdeir, Nasser Mohieddin

2017-07-19

Unlike the canonical application of liquid crystals (LCs), LC displays, emerging technologies based on LC materials are increasingly leveraging the presence of nanoscale defects. The inherent nanoscale characteristics of LC defects present both significant opportunities as well as barriers for the application of this fascinating class of materials. Simulation-based approaches to the study of the effects of confinement and interface anchoring conditions on LC domains has resulted in significant progress over the past decade, where simulations are now able to access experimentally-relevant length scales while simultaneously capturing nanoscale defect structures. In this work, continuum simulations were performed in order to study the dynamics of micron-scale nematic LC spheroids of varying shape. Nematic spheroids are one of the simplest inherently defect-containing LC structures and are relevant to polymer-dispersed LC-based "smart" window technology. Simulation results include nematic phase formation and external field-switching dynamics of nematic spheroids ranging in shape from oblate to prolate. Results include both qualitative and quantitative insight into the complex coupling of nanoscale defect dynamics and structure transitions to micron-scale reorientation. Dynamic mechanisms are presented and related to structural transitions in LC defects present in the nematic domain. Domain-averaged metrics including order parameters and response times are determined for a range of experimentally-accessible electric field strengths. These results have both fundamental and technological relevance, in that increased understanding of LC dynamics in the presence of defects is a key barrier to continued advancement in the field.

Dynamic Yielding and Spall Behavior of Commercially Pure Grade 4 Titanium

NASA Astrophysics Data System (ADS)

Thadhani, Naresh; Whelchel, R. L.; Sanders, Tom; Mehkote, D. S.; Iyer, K. A.; Georgia Instiutute of Technology Collaboration; Johns Hopkins University, Applied Physics Labortaory Collaboration

2015-06-01

The dynamic yielding and fracture (spalling) of commercially pure (grade 4) titanium are investigated using symmetric plate impact experiments over a peak stress range of 5.6 GPa to 12.5 GPa, using the 80-mm single-stage gas-gun. VISAR rear free surface velocity profiles display both a Hugoniot elastic limit (HEL) and a velocity pullback, which are indicative of dynamic compressive yielding and tensile fracture (spalling), respectively. The HEL values appear to show a slight decrease with peak stress from 2.2 GPa to 2.0 GPa along with a corresponding increase in twinning observed in recovered impacted samples. The spall strength on the other hand increases with peak stress from a value of 3.3 GPa to 3.8 GPa and shows a good power law fit with the decompression strain rate. The differing responses in dynamic yield and fracture behavior suggest that void nucleation may be the dominant mechanism affecting the spall strength of grade 4 titanium.

The gravity model of labor migration behavior

NASA Astrophysics Data System (ADS)

Alexandr, Tarasyev; Alexandr, Tarasyev

2017-07-01

In this article, we present a dynamic inter-regional model, that is based on the gravity approach to migration and describes in continuous time the labor force dynamics between a number of conjugate regions. Our modification of the gravity migration model allows to explain the migration processes and to display the impact of migration on the regional economic development both for regions of origin and attraction. The application of our model allows to trace the dependency between salaries levels, total workforce, the number of vacancies and the number unemployed people in simulated regions. Due to the gravity component in our model the accuracy of prediction for migration flows is limited by the distance range between analyzed regions, so this model is tested on a number of conjugate neighbor regions. Future studies will be aimed at development of a multi-level dynamic model, which allows to construct a forecast for unemployment and vacancies trends on the first modeling level and to use these identified parameters on the second level for describing dynamic trajectories of migration flows.

Orientational order of motile defects in active nematics

DOE PAGES

DeCamp, Stephen J.; Redner, Gabriel S.; Baskaran, Aparna; ...

2015-08-17

The study of equilibrium liquid crystals has led to fundamental insights into the nature of ordered materials, as well as many practical applications such as display technologies. Active nematics are a fundamentally different class of liquid crystals, which are driven away from equilibrium by the autonomous motion of their constituent rodlike particles. This internally-generated activity powers the continuous creation and annihilation of topological defects, leading to complex streaming flows whose chaotic dynamics appear to destroy long-range order. Here, we study these dynamics in experimental and computational realizations of active nematics. By tracking thousands of defects over centimeter distances in microtubule-basedmore » active nematics, we identify a non-equilibrium phase characterized by system-spanning orientational order of defects. This emergent order persists over hours despite defect lifetimes of only seconds. Lastly, similar dynamical structures are observed in coarse-grained simulations, suggesting that defect-ordered phases are a generic feature of active nematics.« less

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

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

Nonexplicit change detection in complex dynamic settings: what eye movements reveal.

PubMed

Vachon, François; Vallières, Benoît R; Jones, Dylan M; Tremblay, Sébastien

2012-12-01

We employed a computer-controlled command-and-control (C2) simulation and recorded eye movements to examine the extent and nature of the inability to detect critical changes in dynamic displays when change detection is implicit (i.e., requires no explicit report) to the operator's task. Change blindness-the failure to notice significant changes to a visual scene-may have dire consequences on performance in C2 and surveillance operations. Participants performed a radar-based risk-assessment task involving multiple subtasks. Although participants were not required to explicitly report critical changes to the operational display, change detection was critical in informing decision making. Participants' eye movements were used as an index of visual attention across the display. Nonfixated (i.e., unattended) changes were more likely to be missed than were fixated (i.e., attended) changes, supporting the idea that focused attention is necessary for conscious change detection. The finding of significant pupil dilation for changes undetected but fixated suggests that attended changes can nonetheless be missed because of a failure of attentional processes. Change blindness in complex dynamic displays takes the form of failures in establishing task-appropriate patterns of attentional allocation. These findings have implications in the design of change-detection support tools for dynamic displays and work procedure in C2 and surveillance.

Epitaxial Ge2Sb2Te5 probed by single cycle THz pulses of coherent synchrotron radiation

NASA Astrophysics Data System (ADS)

Bragaglia, V.; Schnegg, A.; Calarco, R.; Holldack, K.

2016-10-01

A THz-probe spectroscopy scheme with laser-induced single cycle pulses of coherent synchrotron radiation is devised and adapted to reveal the dynamic THz transmittance response in epitaxially grown phase change materials upon 800 nm fs-laser excitation. Amorphous (a-) and crystalline (c-) films of the prototypical Ge2Sb2Te5 (GST) alloy are probed with single cycle THz pulses tuned to the spectral range of the highest absorption contrast at 2 THz. After an initial instantaneous sub-picosecond (ps) dynamic THz transmittance drop, the response of a-GST in that range is dominated only by a short recovery time τshort = 2 ps of the excited carriers. On the contrary, the behavior of the c-GST response displays a short decay of 0.85 ps followed by a long one τlong = 90 ps, suggesting that vacancy layers in an ordered c-GST play a role as dissipation channel for photo-induced free carriers.

Thermally-Driven Mantle Plumes Reconcile Hot-spot Observations

NASA Astrophysics Data System (ADS)

Davies, D.; Davies, J.

2008-12-01

Hot-spots are anomalous regions of magmatism that cannot be directly associated with plate tectonic processes (e.g. Morgan, 1972). They are widely regarded as the surface expression of upwelling mantle plumes. Hot-spots exhibit variable life-spans, magmatic productivity and fixity (e.g. Ito and van Keken, 2007). This suggests that a wide-range of upwelling structures coexist within Earth's mantle, a view supported by geochemical and seismic evidence, but, thus far, not reproduced by numerical models. Here, results from a new, global, 3-D spherical, mantle convection model are presented, which better reconcile hot-spot observations, the key modification from previous models being increased convective vigor. Model upwellings show broad-ranging dynamics; some drift slowly, while others are more mobile, displaying variable life-spans, intensities and migration velocities. Such behavior is consistent with hot-spot observations, indicating that the mantle must be simulated at the correct vigor and in the appropriate geometry to reproduce Earth-like dynamics. Thermally-driven mantle plumes can explain the principal features of hot-spot volcanism on Earth.

Computational model of lightness perception in high dynamic range imaging

NASA Astrophysics Data System (ADS)

Krawczyk, Grzegorz; Myszkowski, Karol; Seidel, Hans-Peter

2006-02-01

An anchoring theory of lightness perception by Gilchrist et al. [1999] explains many characteristics of human visual system such as lightness constancy and its spectacular failures which are important in the perception of images. The principal concept of this theory is the perception of complex scenes in terms of groups of consistent areas (frameworks). Such areas, following the gestalt theorists, are defined by the regions of common illumination. The key aspect of the image perception is the estimation of lightness within each framework through the anchoring to the luminance perceived as white, followed by the computation of the global lightness. In this paper we provide a computational model for automatic decomposition of HDR images into frameworks. We derive a tone mapping operator which predicts lightness perception of the real world scenes and aims at its accurate reproduction on low dynamic range displays. Furthermore, such a decomposition into frameworks opens new grounds for local image analysis in view of human perception.

Dynamic Hurricane Data Analysis Tool

NASA Technical Reports Server (NTRS)

Knosp, Brian W.; Li, Peggy; Vu, Quoc A.

2009-01-01

A dynamic hurricane data analysis tool allows users of the JPL Tropical Cyclone Information System (TCIS) to analyze data over a Web medium. The TCIS software is described in the previous article, Tropical Cyclone Information System (TCIS) (NPO-45748). This tool interfaces with the TCIS database to pull in data from several different atmospheric and oceanic data sets, both observed by instruments. Users can use this information to generate histograms, maps, and profile plots for specific storms. The tool also displays statistical values for the user-selected parameter for the mean, standard deviation, median, minimum, and maximum values. There is little wait time, allowing for fast data plots over date and spatial ranges. Users may also zoom-in for a closer look at a particular spatial range. This is version 1 of the software. Researchers will use the data and tools on the TCIS to understand hurricane processes, improve hurricane forecast models and identify what types of measurements the next generation of instruments will need to collect.

Dual-Responsive SPMA-Modified Polymer Photonic Crystals and Their Dynamic Display Patterns.

PubMed

Gao, Zewen; Gao, Dongsheng; Huang, Chao; Zhang, Hanbing; Guo, Jinbao; Wei, Jie

2018-05-28

Light and electrothermal responsive polymer photonic crystals (PCs) modified with 1'-acryloyl chloride-3',3'-dimethyl-6-nitro-spiro(2H-1-benzopyran-2,2'-indoline) (SPMA) are proposed, and their dynamic display patterns are achieved through the combination of the SPMA-modified PCs and a patterned graphite layer. These PCs exhibit fluorescence under UV light irradiation because of the isomerization of the SPMA, which is restricted in the shell of the polymer colloidal spheres. After a voltage is applied to the patterned graphite layer, the fluorescence of PCs in the specific area disappears, and dynamic display patterns are obtained. Under UV light irradiation, the PCs change from the "partial-fluorescence" state to the initial "fluorescence" state, and the patterns disappear. Using this technique, the PC pattern "M L N" on the glass substrate and PC patterns from "0" to "9" on the paper substrate are fabricated. Thus, these dual-responsive PCs have potential applications in information recording, anticounterfeiting, dynamic display, and photoelectric devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Skidmore Clips of Neutral and Expressive Scenarios (SCENES): Novel dynamic stimuli for social cognition research.

PubMed

Schofield, Casey A; Weeks, Justin W; Taylor, Lea; Karnedy, Colten

2015-12-30

Social cognition research has relied primarily on photographic emotional stimuli. Such stimuli likely have limited ecological validity in terms of representing real world social interactions. The current study presents evidence for the validity of a new stimuli set of dynamic social SCENES (Skidmore Clips of Emotional and Neutral Expressive Scenarios). To develop these stimuli, ten undergraduate theater students were recruited to portray members of an audience. This audience was configured to display (seven) varying configurations of social feedback, ranging from unequivocally approving to unequivocally disapproving (including three different versions of balanced/neutral scenes). Validity data were obtained from 383 adult participants recruited from Amazon's Mechanical Turk. Each participant viewed three randomly assigned scenes and provided a rating of the perceived criticalness of each scene. Results indicate that the SCENES reflect the intended range of emotionality, and pairwise comparisons suggest that the SCENES capture distinct levels of critical feedback. Overall, the SCENES stimuli set represents a publicly available (www.scenesstimuli.com) resource for researchers interested in measuring social cognition in the presence of dynamic and naturalistic social stimuli. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Ghost detection and removal based on super-pixel grouping in exposure fusion

NASA Astrophysics Data System (ADS)

Jiang, Shenyu; Xu, Zhihai; Li, Qi; Chen, Yueting; Feng, Huajun

2014-09-01

A novel multi-exposure images fusion method for dynamic scenes is proposed. The commonly used techniques for high dynamic range (HDR) imaging are based on the combination of multiple differently exposed images of the same scene. The drawback of these methods is that ghosting artifacts will be introduced into the final HDR image if the scene is not static. In this paper, a super-pixel grouping based method is proposed to detect the ghost in the image sequences. We introduce the zero mean normalized cross correlation (ZNCC) as a measure of similarity between a given exposure image and the reference. The calculation of ZNCC is implemented in super-pixel level, and the super-pixels which have low correlation with the reference are excluded by adjusting the weight maps for fusion. Without any prior information on camera response function or exposure settings, the proposed method generates low dynamic range (LDR) images which can be shown on conventional display devices directly with details preserving and ghost effects reduced. Experimental results show that the proposed method generates high quality images which have less ghost artifacts and provide a better visual quality than previous approaches.

Supersonic Flight Dynamics Test: Trajectory, Atmosphere, and Aerodynamics Reconstruction

NASA Technical Reports Server (NTRS)

Kutty, Prasad; Karlgaard, Christopher D.; Blood, Eric M.; O'Farrell, Clara; Ginn, Jason M.; Shoenenberger, Mark; Dutta, Soumyo

2015-01-01

The Supersonic Flight Dynamics Test is a full-scale flight test of a Supersonic Inflatable Aerodynamic Decelerator, which is part of the Low Density Supersonic Decelerator technology development project. The purpose of the project is to develop and mature aerodynamic decelerator technologies for landing large mass payloads on the surface of Mars. The technologies include a Supersonic Inflatable Aerodynamic Decelerator and Supersonic Parachutes. The first Supersonic Flight Dynamics Test occurred on June 28th, 2014 at the Pacific Missile Range Facility. This test was used to validate the test architecture for future missions. The flight was a success and, in addition, was able to acquire data on the aerodynamic performance of the supersonic inflatable decelerator. This paper describes the instrumentation, analysis techniques, and acquired flight test data utilized to reconstruct the vehicle trajectory, atmosphere, and aerodynamics. The results of the reconstruction show significantly higher lofting of the trajectory, which can partially be explained by off-nominal booster motor performance. The reconstructed vehicle force and moment coefficients fall well within pre-flight predictions. A parameter identification analysis indicates that the vehicle displayed greater aerodynamic static stability than seen in pre-flight computational predictions and ballistic range tests.

Experimental characterization of the transition to coherence collapse in a semiconductor laser with optical feedback

NASA Astrophysics Data System (ADS)

Panozzo, M.; Quintero-Quiroz, C.; Tiana-Alsina, J.; Torrent, M. C.; Masoller, C.

2017-11-01

Semiconductor lasers with time-delayed optical feedback display a wide range of dynamical regimes, which have found various practical applications. They also provide excellent testbeds for data analysis tools for characterizing complex signals. Recently, several of us have analyzed experimental intensity time-traces and quantitatively identified the onset of different dynamical regimes, as the laser current increases. Specifically, we identified the onset of low-frequency fluctuations (LFFs), where the laser intensity displays abrupt dropouts, and the onset of coherence collapse (CC), where the intensity fluctuations are highly irregular. Here we map these regimes when both, the laser current and the feedback strength vary. We show that the shape of the distribution of intensity fluctuations (characterized by the standard deviation, the skewness, and the kurtosis) allows to distinguish among noise, LFFs and CC, and to quantitatively determine (in spite of the gradual nature of the transitions) the boundaries of the three regimes. Ordinal analysis of the inter-dropout time intervals consistently identifies the three regimes occurring in the same parameter regions as the analysis of the intensity distribution. Simulations of the well-known time-delayed Lang-Kobayashi model are in good qualitative agreement with the observations.

Color Imaging management in film processing

NASA Astrophysics Data System (ADS)

Tremeau, Alain; Konik, Hubert; Colantoni, Philippe

2003-12-01

The latest research projects in the laboratory LIGIV concerns capture, processing, archiving and display of color images considering the trichromatic nature of the Human Vision System (HSV). Among these projects one addresses digital cinematographic film sequences of high resolution and dynamic range. This project aims to optimize the use of content for the post-production operators and for the end user. The studies presented in this paper address the use of metadata to optimise the consumption of video content on a device of user's choice independent of the nature of the equipment that captured the content. Optimising consumption includes enhancing the quality of image reconstruction on a display. Another part of this project addresses the content-based adaptation of image display. Main focus is on Regions of Interest (ROI) operations, based on the ROI concepts of MPEG-7. The aim of this second part is to characterize and ensure the conditions of display even if display device or display media changes. This requires firstly the definition of a reference color space and the definition of bi-directional color transformations for each peripheral device (camera, display, film recorder, etc.). The complicating factor is that different devices have different color gamuts, depending on the chromaticity of their primaries and the ambient illumination under which they are viewed. To match the displayed image to the aimed appearance, all kind of production metadata (camera specification, camera colour primaries, lighting conditions) should be associated to the film material. Metadata and content build together rich content. The author is assumed to specify conditions as known from digital graphics arts. To control image pre-processing and image post-processing, these specifications should be contained in the film's metadata. The specifications are related to the ICC profiles but need additionally consider mesopic viewing conditions.

Programmer's Reference Manual for Dynamic Display Software System

DOT National Transportation Integrated Search

1971-01-01

In 1968, the display sysems group of the Systems Laboratory of the NASA/Electronics Research Center undertook a research task in the area of computer controlled flight information systems for aerospace application. The display laboratory of the Trans...

Effects of expected-value information and display format on recognition of aircraft subsystem abnormalities

NASA Technical Reports Server (NTRS)

Palmer, Michael T.; Abbott, Kathy H.

1994-01-01

This study identifies improved methods to present system parameter information for detecting abnormal conditions and to identify system status. Two workstation experiments were conducted. The first experiment determined if including expected-value-range information in traditional parameter display formats affected subject performance. The second experiment determined if using a nontraditional parameter display format, which presented relative deviation from expected value, was better than traditional formats with expected-value ranges included. The inclusion of expected-value-range information onto traditional parameter formats was found to have essentially no effect. However, subjective results indicated support for including this information. The nontraditional column deviation parameter display format resulted in significantly fewer errors compared with traditional formats with expected-value-ranges included. In addition, error rates for the column deviation parameter display format remained stable as the scenario complexity increased, whereas error rates for the traditional parameter display formats with expected-value ranges increased. Subjective results also indicated that the subjects preferred this new format and thought that their performance was better with it. The column deviation parameter display format is recommended for display applications that require rapid recognition of out-of-tolerance conditions, especially for a large number of parameters.

Restoration of moving binary images degraded owing to phosphor persistence.

PubMed

Cherri, A K; Awwal, A A; Karim, M A; Moon, D L

1991-09-10

The degraded images of dynamic objects obtained by using a phosphor-based electro-optical display are analyzed in terms of dynamic modulation transfer function (DMTF) and temporal characteristics of the display system. The direct correspondence between the DMTF and image smear is used in developing real-time techniques for the restoration of degraded images.

Compensation for time delay in flight simulator visual-display systems

NASA Technical Reports Server (NTRS)

Crane, D. F.

1983-01-01

A piloted aircraft can be viewed as a closed-loop, man-machine control system. When a simulator pilot is performing a precision maneuver, a delay in the visual display of aircraft response to pilot-control input decreases the stability of the pilot-aircraft system. The less stable system is more difficult to control precisely. Pilot dynamic response and performance change as the pilot attempts to compensate for the decrease in system stability, and these changes bias the simulation results by influencing the pilot's rating of the handling qualities of the simulated aircraft. Delay compensation, designed to restore pilot-aircraft system stability, was evaluated in several studies which are reported here. The studies range from single-axis, tracking-task experiments (with sufficient subjects and trials to establish statistical significance of the results) to a brief evaluation of compensation of a computer-generated-imagery (CGI) visual display system in a full six-degree-of-freedom simulation. The compensation was effective - improvements in pilot performance and workload or aircraft handling-qualities rating (HQR) were observed. Results from recent aircraft handling-qualities research literature which support the compensation design approach are also reviewed.

An automated approach for tone mapping operator parameter adjustment in security applications

NASA Astrophysics Data System (ADS)

Krasula, LukáÅ.¡; Narwaria, Manish; Le Callet, Patrick

2014-05-01

High Dynamic Range (HDR) imaging has been gaining popularity in recent years. Different from the traditional low dynamic range (LDR), HDR content tends to be visually more appealing and realistic as it can represent the dynamic range of the visual stimuli present in the real world. As a result, more scene details can be faithfully reproduced. As a direct consequence, the visual quality tends to improve. HDR can be also directly exploited for new applications such as video surveillance and other security tasks. Since more scene details are available in HDR, it can help in identifying/tracking visual information which otherwise might be difficult with typical LDR content due to factors such as lack/excess of illumination, extreme contrast in the scene, etc. On the other hand, with HDR, there might be issues related to increased privacy intrusion. To display the HDR content on the regular screen, tone-mapping operators (TMO) are used. In this paper, we present the universal method for TMO parameters tuning, in order to maintain as many details as possible, which is desirable in security applications. The method's performance is verified on several TMOs by comparing the outcomes from tone-mapping with default and optimized parameters. The results suggest that the proposed approach preserves more information which could be of advantage for security surveillance but, on the other hand, makes us consider possible increase in privacy intrusion.

Nuclei and the Unitary Limit

NASA Astrophysics Data System (ADS)

Hammer, H.-W.

2018-07-01

Few-body systems with large scattering length display universal properties which are independent of the details of short-distance dynamics. These features include universal correlations between few-body observables and a geometric spectrum of three- and higher-body bound states. They can be observed in a wide range of systems from ultracold atoms to hadrons and nuclei. In this contribution, we review universality in nuclei dominated by few-body physics. In particular, we discuss halo nuclei and the description of light nuclei in a strict expansion around the unitary limit of infinite scattering length.

Management and display of four-dimensional environmental data sets using McIDAS

NASA Technical Reports Server (NTRS)

Hibbard, William L.; Santek, David; Suomi, Verner E.

1990-01-01

Over the past four years, great strides have been made in the areas of data management and display of 4-D meteorological data sets. A survey was conducted of available and planned 4-D meteorological data sources. The data types were evaluated for their impact on the data management and display system. The requirements were analyzed for data base management generated by the 4-D data display system. The suitability of the existing data base management procedures and file structure were evaluated in light of the new requirements. Where needed, new data base management tools and file procedures were designed and implemented. The quality of the basic 4-D data sets was assured. The interpolation and extrapolation techniques of the 4-D data were investigated. The 4-D data from various sources were combined to make a uniform and consistent data set for display purposes. Data display software was designed to create abstract line graphic 3-D displays. Realistic shaded 3-D displays were created. Animation routines for these displays were developed in order to produce a dynamic 4-D presentation. A prototype dynamic color stereo workstation was implemented. A computer functional design specification was produced based on interactive studies and user feedback.

A Low-Cost PC-Based Image Workstation for Dynamic Interactive Display of Three-Dimensional Anatomy

NASA Astrophysics Data System (ADS)

Barrett, William A.; Raya, Sai P.; Udupa, Jayaram K.

1989-05-01

A system for interactive definition, automated extraction, and dynamic interactive display of three-dimensional anatomy has been developed and implemented on a low-cost PC-based image workstation. An iconic display is used for staging predefined image sequences through specified increments of tilt and rotation over a solid viewing angle. Use of a fast processor facilitates rapid extraction and rendering of the anatomy into predefined image views. These views are formatted into a display matrix in a large image memory for rapid interactive selection and display of arbitrary spatially adjacent images within the viewing angle, thereby providing motion parallax depth cueing for efficient and accurate perception of true three-dimensional shape, size, structure, and spatial interrelationships of the imaged anatomy. The visual effect is that of holding and rotating the anatomy in the hand.

Nonlinear dynamics of solitary and optically injected two-element laser arrays with four different waveguide structures: a numerical study.

PubMed

Li, Nianqiang; Susanto, H; Cemlyn, B R; Henning, I D; Adams, M J

2018-02-19

We study the nonlinear dynamics of solitary and optically injected two-element laser arrays with a range of waveguide structures. The analysis is performed with a detailed direct numerical simulation, where high-resolution dynamic maps are generated to identify regions of dynamic instability in the parameter space of interest. Our combined one- and two-parameter bifurcation analysis uncovers globally diverse dynamical regimes (steady-state, oscillation, and chaos) in the solitary laser arrays, which are greatly influenced by static design waveguiding structures, the amplitude-phase coupling factor of the electric field, i.e. the linewidth-enhancement factor, as well as the control parameter, e.g. the pump rate. When external optical injection is introduced to one element of the arrays, we show that the whole system can be either injection-locked simultaneously or display rich, different dynamics outside the locking region. The effect of optical injection is to significantly modify the nature and the regions of nonlinear dynamics from those found in the solitary case. We also show similarities and differences (asymmetry) between the oscillation amplitude of the two elements of the array in specific well-defined regions, which hold for all the waveguiding structures considered. Our findings pave the way to a better understanding of dynamic instability in large arrays of lasers.

Neural Computations in a Dynamical System with Multiple Time Scales.

PubMed

Mi, Yuanyuan; Lin, Xiaohan; Wu, Si

2016-01-01

Neural systems display rich short-term dynamics at various levels, e.g., spike-frequency adaptation (SFA) at the single-neuron level, and short-term facilitation (STF) and depression (STD) at the synapse level. These dynamical features typically cover a broad range of time scales and exhibit large diversity in different brain regions. It remains unclear what is the computational benefit for the brain to have such variability in short-term dynamics. In this study, we propose that the brain can exploit such dynamical features to implement multiple seemingly contradictory computations in a single neural circuit. To demonstrate this idea, we use continuous attractor neural network (CANN) as a working model and include STF, SFA and STD with increasing time constants in its dynamics. Three computational tasks are considered, which are persistent activity, adaptation, and anticipative tracking. These tasks require conflicting neural mechanisms, and hence cannot be implemented by a single dynamical feature or any combination with similar time constants. However, with properly coordinated STF, SFA and STD, we show that the network is able to implement the three computational tasks concurrently. We hope this study will shed light on the understanding of how the brain orchestrates its rich dynamics at various levels to realize diverse cognitive functions.

Longitudinal control effectiveness and entry dynamics of a single-stage-to-orbit vehicle

NASA Technical Reports Server (NTRS)

Vinh, N. X.; Lin, C. F.

1982-01-01

The classical theory of flight dynamics for airplane longitudinal stability and control analysis was extended to the case of a hypervelocity reentry vehicle. This includes the elements inherent in supersonic and hypersonic flight such as the influence of the Mach number on aerodynamic characteristics, and the effect of the reaction control system and aerodynamic controls on the trim condition through a wide range of speed. Phugoid motion and angle of attack oscillation for typical cases of cruising flight, ballistic entry, and glide entry are investigated. In each case, closed form solutions for the variations in altitude, flight path angle, speed and angle of attack are obtained. The solutions explicitly display the influence of different regions design parameters and trajectory variables on the stability of the motion.

Actin Filaments and Myosin I Alpha Cooperate with Microtubules for the Movement of LysosomesV⃞

PubMed Central

Cordonnier, Marie-Neige; Dauzonne, Daniel; Louvard, Daniel; Coudrier, Evelyne

2001-01-01

An earlier report suggested that actin and myosin I alpha (MMIα), a myosin associated with endosomes and lysosomes, were involved in the delivery of internalized molecules to lysosomes. To determine whether actin and MMIα were involved in the movement of lysosomes, we analyzed by time-lapse video microscopy the dynamic of lysosomes in living mouse hepatoma cells (BWTG3 cells), producing green fluorescent protein actin or a nonfunctional domain of MMIα. In GFP-actin cells, lysosomes displayed a combination of rapid long-range directional movements dependent on microtubules, short random movements, and pauses, sometimes on actin filaments. We showed that the inhibition of the dynamics of actin filaments by cytochalasin D increased pauses of lysosomes on actin structures, while depolymerization of actin filaments using latrunculin A increased the mobility of lysosomes but impaired the directionality of their long-range movements. The production of a nonfunctional domain of MMIα impaired the intracellular distribution of lysosomes and the directionality of their long-range movements. Altogether, our observations indicate for the first time that both actin filaments and MMIα contribute to the movement of lysosomes in cooperation with microtubules and their associated molecular motors. PMID:11739797

Distinct collective states due to trade-off between attractive and repulsive couplings

NASA Astrophysics Data System (ADS)

Sathiyadevi, K.; Chandrasekar, V. K.; Senthilkumar, D. V.; Lakshmanan, M.

2018-03-01

We investigate the effect of repulsive coupling together with an attractive coupling in a network of nonlocally coupled oscillators. To understand the complex interaction between these two couplings we introduce a control parameter in the repulsive coupling which plays a crucial role in inducing distinct complex collective patterns. In particular, we show the emergence of various cluster chimera death states through a dynamically distinct transition route, namely the oscillatory cluster state and coherent oscillation death state as a function of the repulsive coupling in the presence of the attractive coupling. In the oscillatory cluster state, the oscillators in the network are grouped into two distinct dynamical states of homogeneous and inhomogeneous oscillatory states. Further, the network of coupled oscillators follow the same transition route in the entire coupling range. Depending upon distinct coupling ranges, the system displays different number of clusters in the death state and oscillatory state. We also observe that the number of coherent domains in the oscillatory cluster state exponentially decreases with increase in coupling range and obeys a power-law decay. Additionally, we show analytical stability for observed solitary state, synchronized state, and incoherent oscillation death state.

Functional supramolecular polymers for biomedical applications.

PubMed

Dong, Ruijiao; Zhou, Yongfeng; Huang, Xiaohua; Zhu, Xinyuan; Lu, Yunfeng; Shen, Jian

2015-01-21

As a novel class of dynamic and non-covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide-ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bio-imaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplin-ary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Automatic dynamic range adjustment for ultrasound B-mode imaging.

PubMed

Lee, Yeonhwa; Kang, Jinbum; Yoo, Yangmo

2015-02-01

In medical ultrasound imaging, dynamic range (DR) is defined as the difference between the maximum and minimum values of the displayed signal to display and it is one of the most essential parameters that determine its image quality. Typically, DR is given with a fixed value and adjusted manually by operators, which leads to low clinical productivity and high user dependency. Furthermore, in 3D ultrasound imaging, DR values are unable to be adjusted during 3D data acquisition. A histogram matching method, which equalizes the histogram of an input image based on that from a reference image, can be applied to determine the DR value. However, it could be lead to an over contrasted image. In this paper, a new Automatic Dynamic Range Adjustment (ADRA) method is presented that adaptively adjusts the DR value by manipulating input images similar to a reference image. The proposed ADRA method uses the distance ratio between the log average and each extreme value of a reference image. To evaluate the performance of the ADRA method, the similarity between the reference and input images was measured by computing a correlation coefficient (CC). In in vivo experiments, the CC values were increased by applying the ADRA method from 0.6872 to 0.9870 and from 0.9274 to 0.9939 for kidney and liver data, respectively, compared to the fixed DR case. In addition, the proposed ADRA method showed to outperform the histogram matching method with in vivo liver and kidney data. When using 3D abdominal data with 70 frames, while the CC value from the ADRA method is slightly increased (i.e., 0.6%), the proposed method showed improved image quality in the c-plane compared to its fixed counterpart, which suffered from a shadow artifact. These results indicate that the proposed method can enhance image quality in 2D and 3D ultrasound B-mode imaging by improving the similarity between the reference and input images while eliminating unnecessary manual interaction by the user. Copyright © 2014 Elsevier B.V. All rights reserved.

Infant brain activity while viewing facial movement of point-light displays as measured by near-infrared spectroscopy (NIRS).

PubMed

Ichikawa, Hiroko; Kanazawa, So; Yamaguchi, Masami K; Kakigi, Ryusuke

2010-09-27

Adult observers can quickly identify specific actions performed by an invisible actor from the points of lights attached to the actor's head and major joints. Infants are also sensitive to biological motion and prefer to see it depicted by a dynamic point-light display. In detecting biological motion such as whole body and facial movements, neuroimaging studies have demonstrated the involvement of the occipitotemporal cortex, including the superior temporal sulcus (STS). In the present study, we used the point-light display technique and near-infrared spectroscopy (NIRS) to examine infant brain activity while viewing facial biological motion depicted in a point-light display. Dynamic facial point-light displays (PLD) were made from video recordings of three actors making a facial expression of surprise in a dark room. As in Bassili's study, about 80 luminous markers were scattered over the surface of the actor's faces. In the experiment, we measured infant's hemodynamic responses to these displays using NIRS. We hypothesized that infants would show different neural activity for upright and inverted PLD. The responses were compared to the baseline activation during the presentation of individual still images, which were frames extracted from the dynamic PLD. We found that the concentration of oxy-Hb increased in the right temporal area during the presentation of the upright PLD compared to that of the baseline period. This is the first study to demonstrate that infant's brain activity in face processing is induced only by the motion cue of facial movement depicted by dynamic PLD. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Bioluminescent Antibodies for Point‐of‐Care Diagnostics

PubMed Central

Xue, Lin; Yu, Qiuliyang; Griss, Rudolf; Schena, Alberto

2017-01-01

Abstract We introduce a general method to transform antibodies into ratiometric, bioluminescent sensor proteins for the no‐wash quantification of analytes. Our approach is based on the genetic fusion of antibody fragments to NanoLuc luciferase and SNAP‐tag, the latter being labeled with a synthetic fluorescent competitor of the antigen. Binding of the antigen, here synthetic drugs, by the sensor displaces the tethered fluorescent competitor from the antibody and disrupts bioluminescent resonance energy transfer (BRET) between the luciferase and fluorophore. The semisynthetic sensors display a tunable response range (submicromolar to submillimolar) and large dynamic range (ΔR max>500 %), and they permit the quantification of analytes through spotting of the samples onto paper followed by analysis with a digital camera. PMID:28510347

Dynamic crystallization of silicate melts

NASA Technical Reports Server (NTRS)

Russell, W. J.

1984-01-01

Two types of furnaces with differing temperature range capabilities were used to provide variations in melt temperatures and cooling rates in a study of the effects of heterogeneous nucleation on crystallization. Materials of chondrule composition were used to further understanding of how the disequilibrium features displayed by minerals in rocks are formed. Results show that the textures of natural chondrules were duplicated. It is concluded that the melt history is dominant over cooling rate and composition in controlling texture. The importance of nuclei, which are most readily derived from preexisting crystalline material, support an origin for natural chondrules based on remelting of crystalline material. This would be compatible with a simple, uniform chondrule forming process having only slight variations in thermal histories resulting in the wide range of textures.

The design of a tactical situation display

NASA Astrophysics Data System (ADS)

Kuperman, Gilbert G.; Wilson, Denise L.

The design and demonstration of a dynamic tactical situation display applicable to an advanced conceptual bomber crew system is discussed. The display is the primary source of mission pacing and situational awareness information in the Strategic Avionics Battle-Management Evaluation and Research (SABER) simulator. Aspects of the display design are described, including primary data items, horizontal situation display, point of interest indication, terrain data, graphics overlay, text window, and presentation modes.

A dynamic response and eye scanning data base useful in the development of theories and methods for the description of control/display relationships

NASA Technical Reports Server (NTRS)

Klein, R.

1972-01-01

A set of specially prepared digital tapes is reported which contain synchronized measurements of pilot scanning behavior, control response, and vehicle response obtained during instrument landing system approaches made in a fixed-base DC-8 transport simulator. The objective of the master tape is to provide a common data base which can be used by the research community to test theories, models, and methods for describing and analyzing control/display relations and interactions. The experimental conditions and tasks used to obtain the data and the detailed format of the tapes are described. Conventional instrument panel and controls were used, with simulated vertical gust and glide slope beam bend forcing functions. Continuous pilot eye fixations and scan traffic on the panel were measured. Both flight director and standard localizer/glide slope types of approaches were made, with both fixed and variable instrument range sensitivities.

Reconfigurable and responsive droplet-based compound micro-lenses.

PubMed

Nagelberg, Sara; Zarzar, Lauren D; Nicolas, Natalie; Subramanian, Kaushikaram; Kalow, Julia A; Sresht, Vishnu; Blankschtein, Daniel; Barbastathis, George; Kreysing, Moritz; Swager, Timothy M; Kolle, Mathias

2017-03-07

Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications-integral micro-scale imaging devices and light field display technology-thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses.

Reconfigurable and responsive droplet-based compound micro-lenses

PubMed Central

Nagelberg, Sara; Zarzar, Lauren D.; Nicolas, Natalie; Subramanian, Kaushikaram; Kalow, Julia A.; Sresht, Vishnu; Blankschtein, Daniel; Barbastathis, George; Kreysing, Moritz; Swager, Timothy M.; Kolle, Mathias

2017-01-01

Micro-scale optical components play a crucial role in imaging and display technology, biosensing, beam shaping, optical switching, wavefront-analysis, and device miniaturization. Herein, we demonstrate liquid compound micro-lenses with dynamically tunable focal lengths. We employ bi-phase emulsion droplets fabricated from immiscible hydrocarbon and fluorocarbon liquids to form responsive micro-lenses that can be reconfigured to focus or scatter light, form real or virtual images, and display variable focal lengths. Experimental demonstrations of dynamic refractive control are complemented by theoretical analysis and wave-optical modelling. Additionally, we provide evidence of the micro-lenses' functionality for two potential applications—integral micro-scale imaging devices and light field display technology—thereby demonstrating both the fundamental characteristics and the promising opportunities for fluid-based dynamic refractive micro-scale compound lenses. PMID:28266505

Vision-based calibration of parallax barrier displays

NASA Astrophysics Data System (ADS)

Ranieri, Nicola; Gross, Markus

2014-03-01

Static and dynamic parallax barrier displays became very popular over the past years. Especially for single viewer applications like tablets, phones and other hand-held devices, parallax barriers provide a convenient solution to render stereoscopic content. In our work we present a computer vision based calibration approach to relate image layer and barrier layer of parallax barrier displays with unknown display geometry for static or dynamic viewer positions using homographies. We provide the math and methods to compose the required homographies on the fly and present a way to compute the barrier without the need of any iteration. Our GPU implementation is stable and general and can be used to reduce latency and increase refresh rate of existing and upcoming barrier methods.

Perceptual response to visual noise and display media

NASA Technical Reports Server (NTRS)

Durgin, Frank H.; Proffitt, Dennis R.

1993-01-01

The present project was designed to follow up an earlier investigation in which perceptual adaptation in response to the use of Night Vision Goggles, or image intensification (I squared) systems, such as those employed in the military were studied. Our chief concern in the earlier studies was with the dynamic visual noise that is a byproduct of the I(sup 2) technology: under low light conditions, there is a great deal of 'snow' or sporadic 'twinkling' of pixels in the I(sup 2) display which is more salient as the ambient light levels are lower. Because prolonged exposure to static visual noise produces strong adaptation responses, we reasoned that the dynamic visual noise of I(sup 2) displays might have a similar effect, which could have implications for their long term use. However, in the series of experiments reported last year, no evidence at all of such aftereffects following extended exposure to I(sup 2) displays were found. This finding surprised us, and led us to propose the following studies: (1) an investigation of dynamic visual noise and its capacity to produce after effects; and (2) an investigation of the perceptual consequences of characteristics of the display media.

Evaluation of a computer-generated perspective tunnel display for flight path following

NASA Technical Reports Server (NTRS)

Grunwald, A. J.; Robertson, J. B.; Hatfield, J. J.

1980-01-01

The display was evaluated by monitoring pilot performance in a fixed base simulator with the vehicle dynamics of a CH-47 tandem rotor helicopter. Superposition of the predicted future vehicle position on the tunnel image was also investigated to determine whether, and to what extent, it contributes to better system performance (the best predicted future vehicle position was sought). Three types of simulator experiments were conducted: following a desired trajectory in the presence of disturbances; entering the trajectory from a random position, outside the trajectory; detecting and correcting failures in automatic flight. The tunnel display with superimposed predictor/director symbols was shown to be a very successful combination, which outperformed the other two displays in all three experiments. A prediction time of 4 to 7 sec. was found to optimize trajectory tracking for the given vehicle dynamics and flight condition. Pilot acceptance of the tunnel plus predictor/director display was found to be favorable and the time the pilot needed for familiarization with the display was found to be relatively short.

Carbon Nanotube Driver Circuit for 6 × 6 Organic Light Emitting Diode Display

NASA Astrophysics Data System (ADS)

Zou, Jianping; Zhang, Kang; Li, Jingqi; Zhao, Yongbiao; Wang, Yilei; Pillai, Suresh Kumar Raman; Volkan Demir, Hilmi; Sun, Xiaowei; Chan-Park, Mary B.; Zhang, Qing

2015-06-01

Single-walled carbon nanotube (SWNT) is expected to be a very promising material for flexible and transparent driver circuits for active matrix organic light emitting diode (AM OLED) displays due to its high field-effect mobility, excellent current carrying capacity, optical transparency and mechanical flexibility. Although there have been several publications about SWNT driver circuits, none of them have shown static and dynamic images with the AM OLED displays. Here we report on the first successful chemical vapor deposition (CVD)-grown SWNT network thin film transistor (TFT) driver circuits for static and dynamic AM OLED displays with 6 × 6 pixels. The high device mobility of ~45 cm2V-1s-1 and the high channel current on/off ratio of ~105 of the SWNT-TFTs fully guarantee the control capability to the OLED pixels. Our results suggest that SWNT-TFTs are promising backplane building blocks for future OLED displays.

Carbon Nanotube Driver Circuit for 6 × 6 Organic Light Emitting Diode Display.

PubMed

Zou, Jianping; Zhang, Kang; Li, Jingqi; Zhao, Yongbiao; Wang, Yilei; Pillai, Suresh Kumar Raman; Volkan Demir, Hilmi; Sun, Xiaowei; Chan-Park, Mary B; Zhang, Qing

2015-06-29

Single-walled carbon nanotube (SWNT) is expected to be a very promising material for flexible and transparent driver circuits for active matrix organic light emitting diode (AM OLED) displays due to its high field-effect mobility, excellent current carrying capacity, optical transparency and mechanical flexibility. Although there have been several publications about SWNT driver circuits, none of them have shown static and dynamic images with the AM OLED displays. Here we report on the first successful chemical vapor deposition (CVD)-grown SWNT network thin film transistor (TFT) driver circuits for static and dynamic AM OLED displays with 6 × 6 pixels. The high device mobility of ~45 cm(2)V(-1)s(-1) and the high channel current on/off ratio of ~10(5) of the SWNT-TFTs fully guarantee the control capability to the OLED pixels. Our results suggest that SWNT-TFTs are promising backplane building blocks for future OLED displays.

Time-dependent Increase in the Network Response to the Stimulation of Neuronal Cell Cultures on Micro-electrode Arrays.

PubMed

Gertz, Monica L; Baker, Zachary; Jose, Sharon; Peixoto, Nathalia

2017-05-29

Micro-electrode arrays (MEAs) can be used to investigate drug toxicity, design paradigms for next-generation personalized medicine, and study network dynamics in neuronal cultures. In contrast with more traditional methods, such as patch-clamping, which can only record activity from a single cell, MEAs can record simultaneously from multiple sites in a network, without requiring the arduous task of placing each electrode individually. Moreover, numerous control and stimulation configurations can be easily applied within the same experimental setup, allowing for a broad range of dynamics to be explored. One of the key dynamics of interest in these in vitro studies has been the extent to which cultured networks display properties indicative of learning. Mouse neuronal cells cultured on MEAs display an increase in response following training induced by electrical stimulation. This protocol demonstrates how to culture neuronal cells on MEAs; successfully record from over 95% of the plated dishes; establish a protocol to train the networks to respond to patterns of stimulation; and sort, plot, and interpret the results from such experiments. The use of a proprietary system for stimulating and recording neuronal cultures is demonstrated. Software packages are also used to sort neuronal units. A custom-designed graphical user interface is used to visualize post-stimulus time histograms, inter-burst intervals, and burst duration, as well as to compare the cellular response to stimulation before and after a training protocol. Finally, representative results and future directions of this research effort are discussed.

Polymorphic nuclear markers for coastal plant species with dynamic geographic distributions, the rock samphire (Crithmum maritimum) and the vulnerable dune pansy (Viola tricolor subsp. curtisii).

PubMed

Latron, Mathilde; Arnaud, Jean-François; Ferla, Héloïse; Godé, Cécile; Duputié, Anne

2018-06-01

Identifying spatial patterns of genetic differentiation across a species range is critical to set up conservation and restoration decision-making. This is especially timely, since global change triggers shifts in species' geographic distribution and in the geographical variation of mating system and patterns of genetic differentiation, with varying consequences at the trailing and leading edges of a species' distribution. Using 454 pyrosequencing, we developed nuclear microsatellite loci for two plant species showing a strictly coastal geographical distribution and contrasting range dynamics: the expanding rock samphire (Crithmum maritimum, 21 loci) and the highly endangered and receding dune pansy (Viola tricolor subsp. curtisii, 12 loci). Population genetic structure was then assessed by genotyping more than 100 individuals from four populations of each of the two target species. Rock samphire displayed high levels of genetic differentiation (F ST  = 0.38), and a genetic structure typical of a mostly selfing species (F IS ranging from 0.16 to 0.58). Populations of dune pansy showed a less pronounced level of population structuring (F ST  = 0.25) and a genotypic structure more suggestive of a mixed-mating system when excluding two loci with heterozygote excess. These results demonstrate that the genetic markers developed here are useful to assess the mating system of populations of these two species. They will be tools of choice to investigate phylogeographical patterns and variation in mating system over the geographical distribution ranges for two coastal plant species that are subject to dynamic evolution due to rapid contemporary global change.

Enhanced visualization of abnormalities in digital-mammographic images

NASA Astrophysics Data System (ADS)

Young, Susan S.; Moore, William E.

2002-05-01

This paper describes two new presentation methods that are intended to improve the ability of radiologists to visualize abnormalities in mammograms by enhancing the appearance of the breast parenchyma pattern relative to the fatty-tissue surroundings. The first method, referred to as mountain- view, is obtained via multiscale edge decomposition through filter banks. The image is displayed in a multiscale edge domain that causes the image to have a topographic-like appearance. The second method displays the image in the intensity domain and is referred to as contrast-enhancement presentation. The input image is first passed through a decomposition filter bank to produce a filtered output (Id). The image at the lowest resolution is processed using a LUT (look-up table) to produce a tone scaled image (I'). The LUT is designed to optimally map the code value range corresponding to the parenchyma pattern in the mammographic image into the dynamic range of the output medium. The algorithm uses a contrast weight control mechanism to produce the desired weight factors to enhance the edge information corresponding to the parenchyma pattern. The output image is formed using a reconstruction filter bank through I' and enhanced Id.

Novel computer-based endoscopic camera

NASA Astrophysics Data System (ADS)

Rabinovitz, R.; Hai, N.; Abraham, Martin D.; Adler, Doron; Nissani, M.; Fridental, Ron; Vitsnudel, Ilia

1995-05-01

We have introduced a computer-based endoscopic camera which includes (a) unique real-time digital image processing to optimize image visualization by reducing over exposed glared areas and brightening dark areas, and by accentuating sharpness and fine structures, and (b) patient data documentation and management. The image processing is based on i Sight's iSP1000TM digital video processor chip and Adaptive SensitivityTM patented scheme for capturing and displaying images with wide dynamic range of light, taking into account local neighborhood image conditions and global image statistics. It provides the medical user with the ability to view images under difficult lighting conditions, without losing details `in the dark' or in completely saturated areas. The patient data documentation and management allows storage of images (approximately 1 MB per image for a full 24 bit color image) to any storage device installed into the camera, or to an external host media via network. The patient data which is included with every image described essential information on the patient and procedure. The operator can assign custom data descriptors, and can search for the stored image/data by typing any image descriptor. The camera optics has extended zoom range of f equals 20 - 45 mm allowing control of the diameter of the field which is displayed on the monitor such that the complete field of view of the endoscope can be displayed on all the area of the screen. All these features provide versatile endoscopic camera with excellent image quality and documentation capabilities.

A Preliminary Data Model for Orbital Flight Dynamics in Shuttle Mission Control

NASA Technical Reports Server (NTRS)

ONeill, John; Shalin, Valerie L.

2000-01-01

The Orbital Flight Dynamics group in Shuttle Mission Control is investigating new user interfaces in a project called RIOTS [RIOTS 2000]. Traditionally, the individual functions of hardware and software guide the design of displays, which results in an aggregated, if not integrated interface. The human work system has then been designed and trained to navigate, operate and integrate the processors and displays. The aim of RIOTS is to reduce the cognitive demands of the flight controllers by redesigning the user interface to support the work of the flight controller. This document supports the RIOTS project by defining a preliminary data model for Orbital Flight Dynamics. Section 2 defines an information-centric perspective. An information-centric approach aims to reduce the cognitive workload of the flight controllers by reducing the need for manual integration of information across processors and displays. Section 3 describes the Orbital Flight Dynamics domain. Section 4 defines the preliminary data model for Orbital Flight Dynamics. Section 5 examines the implications of mapping the data model to Orbital Flight Dynamics current information systems. Two recurring patterns are identified in the Orbital Flight Dynamics work the iteration/rework cycle and the decision-making/information integration/mirroring role relationship. Section 6 identifies new requirements on Orbital Flight Dynamics work and makes recommendations based on changing the information environment, changing the implementation of the data model, and changing the two recurring patterns.

Fast dynamics in glass-forming polymers revisited

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

Colmenero, J.; Arbe, A.; Mijangos, C.

1997-12-31

The so called fast-dynamics of glass-forming systems as observed by time of flight (TOF) neutron scattering techniques is revisited. TOF-results corresponding to several glass-forming polymers with different chemical microstructure and glass-transition temperature are presented together with the theoretical framework proposed by the authors to interpret these results. The main conclusion is that the TOF-data can be explained in terms of quasiharmonic vibrations and the particular short time behavior of the segmental dynamics. The segmental dynamics display in the very short time range (t {approx} 2 ps) a crossover from a simple exponential behavior towards a non-exponential regime. The first exponentialmore » decay, which is controlled by C-C rotational barriers, can be understood as a trace of the behavior of the system in absence of the effects (correlations, cooperativity, memory effects {hor_ellipsis}) which characterize the dense supercooled liquid like state against the normal liquid state. The non-exponential regime at t > 2 ps corresponds to what is usually understood as {alpha} and {beta} relaxations. Some implications of these results are also discussed.« less

Effect of color visualization and display hardware on the visual assessment of pseudocolor medical images

PubMed Central

Zabala-Travers, Silvina; Choi, Mina; Cheng, Wei-Chung

2015-01-01

Purpose: Even though the use of color in the interpretation of medical images has increased significantly in recent years, the ad hoc manner in which color is handled and the lack of standard approaches have been associated with suboptimal and inconsistent diagnostic decisions with a negative impact on patient treatment and prognosis. The purpose of this study is to determine if the choice of color scale and display device hardware affects the visual assessment of patterns that have the characteristics of functional medical images. Methods: Perfusion magnetic resonance imaging (MRI) was the basis for designing and performing experiments. Synthetic images resembling brain dynamic-contrast enhanced MRI consisting of scaled mixtures of white, lumpy, and clustered backgrounds were used to assess the performance of a rainbow (“jet”), a heated black-body (“hot”), and a gray (“gray”) color scale with display devices of different quality on the detection of small changes in color intensity. The authors used a two-alternative, forced-choice design where readers were presented with 600 pairs of images. Each pair consisted of two images of the same pattern flipped along the vertical axis with a small difference in intensity. Readers were asked to select the image with the highest intensity. Three differences in intensity were tested on four display devices: a medical-grade three-million-pixel display, a consumer-grade monitor, a tablet device, and a phone. Results: The estimates of percent correct show that jet outperformed hot and gray in the high and low range of the color scales for all devices with a maximum difference in performance of 18% (confidence intervals: 6%, 30%). Performance with hot was different for high and low intensity, comparable to jet for the high range, and worse than gray for lower intensity values. Similar performance was seen between devices using jet and hot, while gray performance was better for handheld devices. Time of performance was shorter with jet. Conclusions: Our findings demonstrate that the choice of color scale and display hardware affects the visual comparative analysis of pseudocolor images. Follow-up studies in clinical settings are being considered to confirm the results with patient images. PMID:26127048

Novel approaches to helicopter obstacle warning

NASA Astrophysics Data System (ADS)

Seidel, Christian; Samuelis, Christian; Wegner, Matthias; Münsterer, Thomas; Rumpf, Thomas; Schwartz, Ingo

2006-05-01

EADS Germany is the world market leader in commercial Helicopter Laser Radar (HELLAS) Obstacle Warning Systems. The HELLAS-Warning System has been introduced into the market in 2000, is in service at German Border Control (Bundespolizei) and Royal Thai Airforce and is successfully evaluated by the Foreign Comparative Test Program (FCT) of the USSOCOM. Currently the successor system HELLAS-Awareness is in development. It will have extended sensor performance, enhanced realtime data processing capabilities and advanced HMI features. We will give an outline of the new sensor unit concerning detection technology and helicopter integration aspects. The system provides a widespread field of view with additional dynamic line of sight steering and a large detection range in combination with a high frame rate of 3Hz. The workflow of the data processing will be presented with focus on novel filter techniques and obstacle classification methods. As commonly known the former are indispensable due to unavoidable statistical measuring errors and solarisation. The amount of information in the filtered raw data is further reduced by ground segmentation. The remaining raised objects are extracted and classified in several stages into different obstacle classes. We will show the prioritization function which orders the obstacles concerning to their threat potential to the helicopter taking into account the actual flight dynamics. The priority of an object determines the display and provision of warnings to the pilot. Possible HMI representation includes video or FLIR overlay on multifunction displays, audio warnings and visualization of information on helmet mounted displays and digital maps. Different concepts will be presented.

Effects of Retinal Eccentricity on Human Manual Control

NASA Technical Reports Server (NTRS)

Popovici, Alexandru; Zaal, Peter M. T.

2017-01-01

This study investigated the effects of viewing a primary flight display at different retinal eccentricities on human manual control behavior and performance. Ten participants performed a pitch tracking task while looking at a simplified primary flight display at different horizontal and vertical retinal eccentricities, and with two different controlled dynamics. Tracking performance declined at higher eccentricity angles and participants behaved more nonlinearly. The visual error rate gain increased with eccentricity for single-integrator-like controlled dynamics, but decreased for double-integrator-like dynamics. Participants' visual time delay was up to 100 ms higher at the highest horizontal eccentricity compared to foveal viewing. Overall, vertical eccentricity had a larger impact than horizontal eccentricity on most of the human manual control parameters and performance. Results might be useful in the design of displays and procedures for critical flight conditions such as in an aerodynamic stall.

Operating scheme for the light-emitting diode array of a volumetric display that exhibits multiple full-color dynamic images

NASA Astrophysics Data System (ADS)

Hirayama, Ryuji; Shiraki, Atsushi; Nakayama, Hirotaka; Kakue, Takashi; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

2017-07-01

We designed and developed a control circuit for a three-dimensional (3-D) light-emitting diode (LED) array to be used in volumetric displays exhibiting full-color dynamic 3-D images. The circuit was implemented on a field-programmable gate array; therefore, pulse-width modulation, which requires high-speed processing, could be operated in real time. We experimentally evaluated the developed system by measuring the luminance of an LED with varying input and confirmed that the system works appropriately. In addition, we demonstrated that the volumetric display exhibits different full-color dynamic two-dimensional images in two orthogonal directions. Each of the exhibited images could be obtained only from the prescribed viewpoint. Such directional characteristics of the system are beneficial for applications, including digital signage, security systems, art, and amusement.

The F-BAR domains from srGAP1, srGAP2 and srGAP3 regulate membrane deformation differently

PubMed Central

Coutinho-Budd, Jaeda; Ghukasyan, Vladimir; Zylka, Mark J.; Polleux, Franck

2012-01-01

Summary Coordination of membrane deformation and cytoskeletal dynamics lies at the heart of many biological processes critical for cell polarity, motility and morphogenesis. We have recently shown that Slit-Robo GTPase-activating protein 2 (srGAP2) regulates neuronal morphogenesis through the ability of its F-BAR domain to regulate membrane deformation and induce filopodia formation. Here, we demonstrate that the F-BAR domains of two closely related family members, srGAP1 and srGAP3 [designated F-BAR(1) and F-BAR(3), respectively] display significantly different membrane deformation properties in non-neuronal COS7 cells and in cortical neurons. F-BAR(3) induces filopodia in both cell types, though less potently than F-BAR(2), whereas F-BAR(1) prevents filopodia formation in cortical neurons and reduces plasma membrane dynamics. These three F-BAR domains can heterodimerize, and they act synergistically towards filopodia induction in COS7 cells. As measured by fluorescence recovery after photobleaching, F-BAR(2) displays faster molecular dynamics than F-BAR(3) and F-BAR(1) at the plasma membrane, which correlates well with its increased potency to induce filopodia. We also show that the molecular dynamic properties of F-BAR(2) at the membrane are partially dependent on F-Actin. Interestingly, acute phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] depletion in cells does not interfere with plasma membrane localization of F-BAR(2), which is compatible with our result showing that F-BAR(2) binds to a broad range of negatively-charged phospholipids present at the plasma membrane, including phosphatidylserine (PtdSer). Overall, our results provide novel insights into the functional diversity of the membrane deformation properties of this subclass of F-BAR-domains required for cell morphogenesis. PMID:22467852

Dynamic laser beam shaping for material processing using hybrid holograms

NASA Astrophysics Data System (ADS)

Liu, Dun; Wang, Yutao; Zhai, Zhongsheng; Fang, Zheng; Tao, Qing; Perrie, Walter; Edwarson, Stuart P.; Dearden, Geoff

2018-06-01

A high quality, dynamic laser beam shaping method is demonstrated by displaying a series of hybrid holograms onto a spatial light modulator (SLM), while each one of the holograms consists of a binary grating and a geometric mask. A diffraction effect around the shaped beam has been significantly reduced. Beam profiles of arbitrary shape, such as square, ring, triangle, pentagon and hexagon, can be conveniently obtained by loading the corresponding holograms on the SLM. The shaped beam can be reconstructed in the range of 0.5 mm at the image plane. Ablation on a polished stainless steel sample at the image plane are consistent with the beam shape at the diffraction near-field. The ±1st order and higher order beams can be completely removed when the grating period is smaller than 160 μm. The local energy ratio of the shaped beam observed by the CCD camera is up to 77.67%. Dynamic processing at 25 Hz using different shapes has also been achieved.

Extraordinary variability and sharp transitions in a maximally frustrated dynamic network

NASA Astrophysics Data System (ADS)

Liu, Wenjia; Schmittmann, Beate; Zia, R. K. P.

2013-03-01

Most previous studies of complex networks have focused on single, static networks. However, in the real world, networks are dynamic and interconnected. Inspired by the presence of extroverts and introverts in the general population, we investigate a highly simplified model of a social network, involving two types of nodes: one preferring the highest degree possible, and one preferring no connections whatsoever. There are only two control parameters in the model: the number of ``introvert'' and ``extrovert'' nodes, NI and NE. Our key findings are as follows: As a function of NI and NE, the system exhibits a highly unusual transition, displaying extraordinary fluctuations (as in 2nd order transitions) and discontinuous jumps (characteristic of 1st order transitions). Most remarkably, the system can be described by an Ising-like Hamiltonian with long-range multi-spin interactions and some of its properties can be obtained analytically. This is in stark contrast with other dynamic network models which rely almost exclusively on simulations. NSF-DMR-1005417/1244666 and and ICTAS Virginia Tech

Dynamics of a grain-filled ball on a vibrating plate.

PubMed

Pacheco-Vázquez, F; Ludewig, F; Dorbolo, S

2014-09-12

We study experimentally how the bouncing dynamics of a hollow ball on a vibrating plate is modified when it is partially filled with liquid or grains. Whereas empty and liquid-filled balls display a dominant chaotic dynamics, a ball with grains exhibits a rich variety of stationary states, determined by the grain size and filling volume. In the collisional regime, i.e., when the energy injected to the system is mainly dissipated by interparticle collisions, an unexpected period-1 orbit appears independently of the vibration conditions, over a wide range. This is a self-regulated state driven by the formation and collapse of a granular gas within the ball during one cycle. In the frictional regime (dissipation dominated by friction), the grains move collectively and generate different patterns and steady modes: oscillons, waves, period doubling, etc. From a phase diagram and a geometrical analysis, we deduce that these modes are the result of a coupling (synchronization) between the vibrating plate frequency and the trajectory followed by the particles inside the cavity.

Dynamics of a Grain-Filled Ball on a Vibrating Plate

NASA Astrophysics Data System (ADS)

Pacheco-Vázquez, F.; Ludewig, F.; Dorbolo, S.

2014-09-01

We study experimentally how the bouncing dynamics of a hollow ball on a vibrating plate is modified when it is partially filled with liquid or grains. Whereas empty and liquid-filled balls display a dominant chaotic dynamics, a ball with grains exhibits a rich variety of stationary states, determined by the grain size and filling volume. In the collisional regime, i.e., when the energy injected to the system is mainly dissipated by interparticle collisions, an unexpected period-1 orbit appears independently of the vibration conditions, over a wide range. This is a self-regulated state driven by the formation and collapse of a granular gas within the ball during one cycle. In the frictional regime (dissipation dominated by friction), the grains move collectively and generate different patterns and steady modes: oscillons, waves, period doubling, etc. From a phase diagram and a geometrical analysis, we deduce that these modes are the result of a coupling (synchronization) between the vibrating plate frequency and the trajectory followed by the particles inside the cavity.

Asynchronous spatial evolutionary games.

PubMed

Newth, David; Cornforth, David

2009-02-01

Over the past 50 years, much attention has been given to the Prisoner's Dilemma as a metaphor for problems surrounding the evolution and maintenance of cooperative and altruistic behavior. The bulk of this work has dealt with the successfulness and robustness of various strategies. Nowak and May (1992) considered an alternative approach to studying evolutionary games. They assumed that players were distributed across a two-dimensional (2D) lattice, interactions between players occurred locally, rather than at long range as in the well mixed situation. The resulting spatial evolutionary games display dynamics not seen in their well-mixed counterparts. An assumption underlying much of the work on spatial evolutionary games is that the state of all players is updated in unison or in synchrony. Using the framework outlined in Nowak and May (1992), we examine the effect of various asynchronous updating schemes on the dynamics of spatial evolutionary games. There are potential implications for the dynamics of a wide variety of spatially extended systems in biology, physics and chemistry.

Random Evolution of Idiotypic Networks: Dynamics and Architecture

NASA Astrophysics Data System (ADS)

Brede, Markus; Behn, Ulrich

The paper deals with modelling a subsystem of the immune system, the so-called idiotypic network (INW). INWs, conceived by N.K. Jerne in 1974, are functional networks of interacting antibodies and B cells. In principle, Jernes' framework provides solutions to many issues in immunology, such as immunological memory, mechanisms for antigen recognition and self/non-self discrimination. Explaining the interconnection between the elementary components, local dynamics, network formation and architecture, and possible modes of global system function appears to be an ideal playground of statistical mechanics. We present a simple cellular automaton model, based on a graph representation of the system. From a simplified description of idiotypic interactions, rules for the random evolution of networks of occupied and empty sites on these graphs are derived. In certain biologically relevant parameter ranges the resultant dynamics leads to stationary states. A stationary state is found to correspond to a specific pattern of network organization. It turns out that even these very simple rules give rise to a multitude of different kinds of patterns. We characterize these networks by classifying `static' and `dynamic' network-patterns. A type of `dynamic' network is found to display many features of real INWs.

Tensile stress-strain and work hardening behaviour of P9 steel for wrapper application in sodium cooled fast reactors

NASA Astrophysics Data System (ADS)

Christopher, J.; Choudhary, B. K.; Isaac Samuel, E.; Mathew, M. D.; Jayakumar, T.

2012-01-01

Tensile flow behaviour of P9 steel with different silicon content has been examined in the framework of Hollomon, Ludwik, Swift, Ludwigson and Voce relationships for a wide temperature range (300-873 K) at a strain rate of 1.3 × 10 -3 s -1. Ludwigson equation described true stress ( σ)-true plastic strain ( ɛ) data most accurately in the range 300-723 K. At high temperatures (773-873 K), Ludwigson equation reduces to Hollomon equation. The variations of instantaneous work hardening rate ( θ = dσ/ dɛ) and θσ with stress indicated two-stage work hardening behaviour. True stress-true plastic strain, flow parameters, θ vs. σ and θσ vs. σ with respect to temperature exhibited three distinct temperature regimes and displayed anomalous behaviour due to dynamic strain ageing at intermediate temperatures. Rapid decrease in flow stress and flow parameters, and rapid shift in θ- σ and θσ- σ towards lower stresses with increase in temperature indicated dominance of dynamic recovery at high temperatures.

Acousto-optic RF signal acquisition system

NASA Astrophysics Data System (ADS)

Bloxham, Laurence H.

1990-09-01

This paper describes the architecture and performance of a prototype Acousto-Optic RF Signal Acquisition System designed to intercept, automatically identify, and track communication signals in the VHF band. The system covers 28.0 to 92.0 MHz with five manually selectable, dual conversion; 12.8 MHZ bandwidth front ends. An acousto-optic spectrum analyzer (AOSA) implemented using a tellurium dioxide (Te02) Bragg cell is used to channelize the 12.8 MHz pass band into 512 25 KHz channels. Polarization switching is used to suppress optical noise. Excellent isolation and dynamic range are achieved by using a linear array of 512 custom 40/50 micron fiber optic cables to collect the light at the focal plane of the AOSA and route the light to individual photodetectors. The photodetectors are operated in the photovoltaic mode to compress the greater than 60 dB input optical dynamic range into an easily processed electrical signal. The 512 signals are multiplexed and processed as a line in a video image by a customized digital image processing system. The image processor simultaneously analyzes the channelized signal data and produces a classical waterfall display.

Non-equlibrium relaxation of vortex lines in disordered type-II superconductors

NASA Astrophysics Data System (ADS)

Dobramysl, Ulrich; Assi, Hiba; Pleimling, Michel; T&äUber, Uwe C.

2013-03-01

Vortex matter in disordered type-II superconductors display a remarkable wealth of behavior, ranging from hexagonally arranged crystals and a vortex liquid to glassy phases. The type and strength of the disorder has a profound influence on the structural properties of the vortex matter: Randomly distributed weak point pinning sites lead to the destruction of long range order and a Bragg glass phase; correlated, columnar disorder can yield a Bose glass phase with infinite tilt modulus. We employ a three-dimensional elastic line model and apply a Langevin molecular dynamics algorithm to simulate the dynamics of vortex lines in a dissipative medium. We investigate the relaxation of a system of lines that were initially prepared in an out-of-equilibrium state and characterize the transient behavior via two-time quantities. We vary the disorder type and strength and compare our results for random and columnar disorder. Research supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-09ER46613.

Objective quality assessment of tone-mapped images.

PubMed

Yeganeh, Hojatollah; Wang, Zhou

2013-02-01

Tone-mapping operators (TMOs) that convert high dynamic range (HDR) to low dynamic range (LDR) images provide practically useful tools for the visualization of HDR images on standard LDR displays. Different TMOs create different tone-mapped images, and a natural question is which one has the best quality. Without an appropriate quality measure, different TMOs cannot be compared, and further improvement is directionless. Subjective rating may be a reliable evaluation method, but it is expensive and time consuming, and more importantly, is difficult to be embedded into optimization frameworks. Here we propose an objective quality assessment algorithm for tone-mapped images by combining: 1) a multiscale signal fidelity measure on the basis of a modified structural similarity index and 2) a naturalness measure on the basis of intensity statistics of natural images. Validations using independent subject-rated image databases show good correlations between subjective ranking score and the proposed tone-mapped image quality index (TMQI). Furthermore, we demonstrate the extended applications of TMQI using two examples-parameter tuning for TMOs and adaptive fusion of multiple tone-mapped images.

Highly Sensitive and Long Term Stable Electrochemical Microelectrodes for Implantable Glucose Monitoring Devices

NASA Astrophysics Data System (ADS)

Qiang, Liangliang

A miniature wireless implantable electrochemical glucose system for continuous glucose monitoring with good selectivity, sensitivity, linearity and long term stability was developed. First, highly sensitive, long-term stable and reusable planar H2O2 microelectrodes have been fabricated by microlithography. These electrodes composed of a 300 nm Pt black layer situated on a 5 um thick Au layer, provide effective protection to the underlying chromium adhesion layer. Using repeated cyclic voltammetric sweeps in flowing buffer solution, highly sensitive Pt black working electrodes were realized with five-decade linear dynamic range and low detection limit (10 nM) for H2O2 at low oxidation potentials. Second, a highly sensitive, low cost and flexible microwire biosensor was described using 25-mum thick gold wire as working electrode together with 125-mum thick Pt/Ir and Ag wires as counter and reference electrode, embedded within a PDMS-filled polyethylene tube. Surface area and activity of sensor was enhanced by converting gold electrode to nanoporous configuration followed by electrodeposition of platinum black. Glucose oxidase based biosensors by electrodeposition of poly(o-phenylenediamine) and glucose oxidase on the working electrode, displayed a higher glucose sensitivity (1.2 mA mM-1 cm-2) than highest literature reported. In addition it exhibits wide detection range (up to 20 mM) and selectivity (>95%). Third, novel miniaturized and flexible microelectrode arrays with 8 of 25 mum electrodes displayed the much needed 3D diffusion profiles similar to a single 25 mum microelectrode, but with one order increase in current levels. These microelectrode arrays displayed a H2O2 sensitivity of 13 mA mM-1 cm-2, a wide dynamic range of 100 nM to 10 mM, limit of detection of 10 nM. These microwire based edge plane microsensors incorporated flexibility, miniaturization and low operation potential are an promising approach for continuous in vivo metabolic monitoring. Fourth, homemade miniature wireless potentisotat was fabricated based on low power consumption integrated circuits and surface mount parts. The miniature wireless potentisotat with up to two week life-time for continuous glucose sensing has a size less than 9x22x10 mm and weight ˜3.4 grams. Primary in vivo experiment showed homemade system has the exactly same respond and trend as commercial glucose meter.

Single Particle Dynamic Imaging and Fe3+ Sensing with Bright Carbon Dots Derived from Bovine Serum Albumin Proteins

NASA Astrophysics Data System (ADS)

Yang, Qingxiu; Wei, Lin; Zheng, Xuanfang; Xiao, Lehui

2015-12-01

In this work, we demonstrated a convenient and green strategy for the synthesis of highly luminescent and water-soluble carbon dots (Cdots) by carbonizing carbon precursors, i.e., Bovine serum albumin (BSA) nanoparticles, in water solution. Without post surface modification, the as-synthesized Cdots exhibit fluorescence quantum yield (Q.Y.) as high as 34.8% and display superior colloidal stability not only in concentrated salt solutions (e.g. 2 M KCl) but also in a wide range of pH solutions. According to the FT-IR measurements, the Cdots contain many carboxyl groups, providing a versatile route for further chemical and biological functionalization. Through conjugation of Cdots with the transacting activator of transcription (TAT) peptide (a kind of cell penetration peptide (CPP)) derived from human immunodeficiency virus (HIV), it is possible to directly monitor the dynamic interactions of CPP with living cell membrane at single particle level. Furthermore, these Cdots also exhibit a dosage-dependent selectivity toward Fe3+ among other metal ions, including K+, Na+, Mg2+, Hg2+, Co2+, Cu2+, Pb2+ and Al3+. We believed that the Cdots prepared by this strategy would display promising applications in various areas, including analytical chemistry, nanomedicine, biochemistry and so on.

Color changing plasmonic surfaces utilizing liquid crystal (Conference Presentation)

NASA Astrophysics Data System (ADS)

Franklin, Daniel; Wu, Shin-Tson; Chanda, Debashis

2016-09-01

Plasmonic structural color has recently garnered significant interest as an alternative to the organic dyes standard in print media and liquid crystal displays. These nanostructured metallic systems can produce diffraction limited images, be made polarization dependent, and exhibit resistance to color bleaching. Perhaps even more advantageous, their optical characteristics can also be tuned, post-fabrication, by altering the surrounding media's refractive index parallel to the local plasmonic fields. A common material with which to achieve this is liquid crystal. By reorienting the liquid crystal molecules through external electric fields, the optical resonances of the plasmonic filters can be dynamically controlled. Demonstrations of this phenomenon, however, have been limited to modest shifts in plasmon resonance. Here, we report a liquid crystal-plasmonic system with an enhanced tuning range through the use of a shallow array of nano-wells and high birefringent liquid crystal. The continuous metallic nanostructure maximizes the overlap between plasmonic fields and liquid crystal while also allowing full reorientation of the liquid crystal upon an applied electric field. Sweeping over structural dimensions and voltages results in a color palette for these dynamic reflective pixels that can further be exploited to create color tunable images. These advances make plasmonic-liquid crystal systems more attractive candidates for filter, display, and other tunable optical technologies.

Polymeric assembly of gluten proteins in an aqueous ethanol solvent.

PubMed

Dahesh, Mohsen; Banc, Amélie; Duri, Agnès; Morel, Marie-Hélène; Ramos, Laurence

2014-09-25

The supramolecular organization of wheat gluten proteins is largely unknown due to the intrinsic complexity of this family of proteins and their insolubility in water. We fractionate gluten in a water/ethanol mixture (50/50 v/v) and obtain a protein extract which is depleted in gliadin, the monomeric part of wheat gluten proteins, and enriched in glutenin, the polymeric part of wheat gluten proteins. We investigate the structure of the proteins in the solvent used for extraction over a wide range of concentration, by combining X-ray scattering and multiangle static and dynamic light scattering. Our data show that, in the ethanol/water mixture, the proteins display features characteristic of flexible polymer chains in a good solvent. In the dilute regime, the proteins form very loose structures of characteristic size 150 nm, with an internal dynamics which is quantitatively similar to that of branched polymer coils. In more concentrated regimes, data highlight a hierarchical structure with one characteristic length scale of the order of a few nm, which displays the scaling with concentration expected for a semidilute polymer in good solvent, and a fractal arrangement at a much larger length scale. This structure is strikingly similar to that of polymeric gels, thus providing some factual knowledge to rationalize the viscoelastic properties of wheat gluten proteins and their assemblies.

Proceedings of the 8th Annual Conference on Manual Control

NASA Technical Reports Server (NTRS)

Pew, R. W.

1972-01-01

The volume presents recent developments in the field of manual control theory and applications. The papers give analytical methods as well as examples of the important interplay between man and machine, such as how man controls and stabilizes machine dynamics, and how machines extend man's capability. Included in the broad range of subjects are procedures to evaluate and identify display systems, controllers, manipulators, human operators, aircraft, and non-flying vehicles. Of particular interest is the continuing trend of applying control theory to problems in medicine and psychology, as well as to problems in vehicle control.

Physiological Costs of Repetitive Courtship Displays in Cockroaches Handicap Locomotor Performance

PubMed Central

Mowles, Sophie L.; Jepson, Natalie M.

2015-01-01

Courtship displays are typically thought to have evolved via female choice, whereby females select mates based on the characteristics of a display that is expected to honestly reflect some aspect of the male’s quality. Honesty is typically enforced by mechanistic costs and constraints that limit the level at which a display can be performed. It is becoming increasingly apparent that these costs may be energetic costs involved in the production of dynamic, often repetitive displays. A female attending to such a display may thus be assessing the physical fitness of a male as an index of his quality. Such assessment would provide information on his current physical quality as well as his ability to carry out other demanding activities, qualities with which a choosy female should want to provision her offspring. In the current study we use courtship interactions in the Cuban burrowing cockroach, Byrsotria fumigata to directly test whether courtship is associated with a signaler’s performance capacity. Males that had produced courtship displays achieved significantly lower speeds and distances in locomotor trials than non-courting control males. We also found that females mated more readily with males that produced a more vigorous display. Thus, males of this species have developed a strategy where they produce a demanding courtship display, while females choose males based on their ability to produce this display. Courtship displays in many taxa often involve dynamic repetitive actions and as such, signals of stamina in courtship may be more widespread than previously thought. PMID:26606147

Breeding biology and the evolution of dynamic sexual dichromatism in frogs.

PubMed

Bell, R C; Webster, G N; Whiting, M J

2017-12-01

Dynamic sexual dichromatism is a temporary colour change between the sexes and has evolved independently in a wide range of anurans, many of which are explosive breeders wherein males physically compete for access to females. Behavioural studies in a few species indicate that dynamic dichromatism functions as a visual signal in large breeding aggregations; however, the prevalence of this trait and the social and environmental factors underlying its expression are poorly understood. We compiled a database of 178 anurans with dynamic dichromatism that include representatives from 15 families and subfamilies. Dynamic dichromatism is common in two of the three subfamilies of hylid treefrogs. Phylogenetic comparative analyses of 355 hylid species (of which 95 display dynamic dichromatism) reveal high transition rates between dynamic dichromatism, ontogenetic (permanent) dichromatism and monochromatism reflecting the high evolutionary lability of this trait. Correlated evolution in hylids between dynamic dichromatism and forming large breeding aggregations indicates that the evolution of large breeding aggregations precedes the evolution of dynamic dichromatism. Multivariate phylogenetic logistic regression recovers the interaction between biogeographic distribution and forming breeding aggregations as a significant predictor of dynamic dichromatism in hylids. Accounting for macroecological differences between temperate and tropical regions, such as seasonality and the availability of breeding sites, may improve our understanding of ecological contexts in which dynamic dichromatism is likely to arise in tropical lineages and why it is retained in some temperate species and lost in others. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Bioluminescent Antibodies for Point-of-Care Diagnostics.

PubMed

Xue, Lin; Yu, Qiuliyang; Griss, Rudolf; Schena, Alberto; Johnsson, Kai

2017-06-12

We introduce a general method to transform antibodies into ratiometric, bioluminescent sensor proteins for the no-wash quantification of analytes. Our approach is based on the genetic fusion of antibody fragments to NanoLuc luciferase and SNAP-tag, the latter being labeled with a synthetic fluorescent competitor of the antigen. Binding of the antigen, here synthetic drugs, by the sensor displaces the tethered fluorescent competitor from the antibody and disrupts bioluminescent resonance energy transfer (BRET) between the luciferase and fluorophore. The semisynthetic sensors display a tunable response range (submicromolar to submillimolar) and large dynamic range (ΔR max >500 %), and they permit the quantification of analytes through spotting of the samples onto paper followed by analysis with a digital camera. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Method and apparatus for monitoring dynamic cardiovascular function using n-dimensional representatives of critical functions

NASA Technical Reports Server (NTRS)

Syroid, Noah (Inventor); Westinskow, Dwayne (Inventor); Agutter, James (Inventor); Albert, Robert (Inventor); Strayer, David (Inventor); Wachter, S. Blake (Inventor); Drews, Frank (Inventor)

2010-01-01

A method, system, apparatus and device for the monitoring, diagnosis and evaluation of the state of a dynamic pulmonary system is disclosed. This method and system provides the processing means for receiving sensed and/or simulated data, converting such data into a displayable object format and displaying such objects in a manner such that the interrelationships between the respective variables can be correlated and identified by a user. This invention provides for the rapid cognitive grasp of the overall state of a pulmonary critical function with respect to a dynamic system.

A characterization of low luminance static and dynamic modulation transfer function curves for P-1, P-43, and P-53 phosphorus

NASA Astrophysics Data System (ADS)

Beasley, Howard H.; Martin, John S.; Klymenko, Victor; Harding, Thomas H.; Verona, Robert W.; Rash, Clarence E.

1995-07-01

A counterphase modulation technique is used to measure the static and dynamic modulation transfer functions for three phosphorus of current interest to U.S. Army aviation helmet-mounted displays (P-1, P-43, and P-53). A family of modulation transfer curves, one for each temporal frequency, is presented for each phosphorus. The measured MFT curves generally support the supposition that phosphorus persistence is a critical parameter in the ability of a CRT display to accurately reproduce contrast modulation transfer in dynamic environments.

Persistence and stochastic periodicity in the intensity dynamics of a fiber laser during the transition to optical turbulence

NASA Astrophysics Data System (ADS)

Carpi, Laura; Masoller, Cristina

2018-02-01

Many natural systems display transitions among different dynamical regimes, which are difficult to identify when the data are noisy and high dimensional. A technologically relevant example is a fiber laser, which can display complex dynamical behaviors that involve nonlinear interactions of millions of cavity modes. Here we study the laminar-turbulence transition that occurs when the laser pump power is increased. By applying various data analysis tools to empirical intensity time series we characterize their persistence and demonstrate that at the transition temporal correlations can be precisely represented by a surprisingly simple model.

Sleep: An Open-Source Python Software for Visualization, Analysis, and Staging of Sleep Data

PubMed Central

Combrisson, Etienne; Vallat, Raphael; Eichenlaub, Jean-Baptiste; O'Reilly, Christian; Lajnef, Tarek; Guillot, Aymeric; Ruby, Perrine M.; Jerbi, Karim

2017-01-01

We introduce Sleep, a new Python open-source graphical user interface (GUI) dedicated to visualization, scoring and analyses of sleep data. Among its most prominent features are: (1) Dynamic display of polysomnographic data, spectrogram, hypnogram and topographic maps with several customizable parameters, (2) Implementation of several automatic detection of sleep features such as spindles, K-complexes, slow waves, and rapid eye movements (REM), (3) Implementation of practical signal processing tools such as re-referencing or filtering, and (4) Display of main descriptive statistics including publication-ready tables and figures. The software package supports loading and reading raw EEG data from standard file formats such as European Data Format, in addition to a range of commercial data formats. Most importantly, Sleep is built on top of the VisPy library, which provides GPU-based fast and high-level visualization. As a result, it is capable of efficiently handling and displaying large sleep datasets. Sleep is freely available (http://visbrain.org/sleep) and comes with sample datasets and an extensive documentation. Novel functionalities will continue to be added and open-science community efforts are expected to enhance the capacities of this module. PMID:28983246

Sleep: An Open-Source Python Software for Visualization, Analysis, and Staging of Sleep Data.

PubMed

Combrisson, Etienne; Vallat, Raphael; Eichenlaub, Jean-Baptiste; O'Reilly, Christian; Lajnef, Tarek; Guillot, Aymeric; Ruby, Perrine M; Jerbi, Karim

2017-01-01

We introduce Sleep, a new Python open-source graphical user interface (GUI) dedicated to visualization, scoring and analyses of sleep data. Among its most prominent features are: (1) Dynamic display of polysomnographic data, spectrogram, hypnogram and topographic maps with several customizable parameters, (2) Implementation of several automatic detection of sleep features such as spindles, K-complexes, slow waves, and rapid eye movements (REM), (3) Implementation of practical signal processing tools such as re-referencing or filtering, and (4) Display of main descriptive statistics including publication-ready tables and figures. The software package supports loading and reading raw EEG data from standard file formats such as European Data Format, in addition to a range of commercial data formats. Most importantly, Sleep is built on top of the VisPy library, which provides GPU-based fast and high-level visualization. As a result, it is capable of efficiently handling and displaying large sleep datasets. Sleep is freely available (http://visbrain.org/sleep) and comes with sample datasets and an extensive documentation. Novel functionalities will continue to be added and open-science community efforts are expected to enhance the capacities of this module.

The effects of time delay in man-machine control systems: Implications for design of flight simulator Visual-Display-Delay compensation

NASA Technical Reports Server (NTRS)

Crane, D. F.

1984-01-01

When human operators are performing precision tracking tasks, their dynamic response can often be modeled by quasilinear describing functions. That fact permits analysis of the effects of delay in certain man machine control systems using linear control system analysis techniques. The analysis indicates that a reduction in system stability is the immediate effect of additional control system delay, and that system characteristics moderate or exaggerate the importance of the delay. A selection of data (simulator and flight test) consistent with the analysis is reviewed. Flight simulator visual-display delay compensation, designed to restore pilot aircraft system stability, was evaluated in several studies which are reviewed here. The studies range from single-axis, tracking-task experiments (with sufficient subjects and trials to establish the statistical significance of the results) to a brief evaluation of compensation of a computer generated imagery (CGI) visual display system in a full six degree of freedom simulation. The compensation was effective, improvements in pilot performance and workload or aircraft handling qualities rating (HQR) were observed. Results from recent aircraft handling qualities research literature, which support the compensation design approach, are also reviewed.

Research on Chinese characters display of airborne MFD based on GL studio

NASA Astrophysics Data System (ADS)

Wang, Zhile; Dong, Junyu; Hu, Wenting; Cui, Yipeng

2018-04-01

GL Studio cannot display Chinese characters during developing the airborne MFD, this paper propose a method of establishing a Chinese character font with GB2312 encoding, establish the font table and the display unit of Chinese characters based on GL Studio. Abstract the storage and display data model of Chinese characters, parse the GB encoding of the corresponding Chinese characters that MFD received, find the coordinates of the Chinese characters in the font table, establish the dynamic control model and the dynamic display model of Chinese characters based on the display unit of Chinese characters. In GL Studio and VC ++.NET environment, this model has been successfully applied to develop the airborne MFD in a variety of mission simulators. This method has successfully solved the problem that GL Studio software cannot develop MFD software of Chinese domestic aircraft and can also be used for other professional airborne MFD development tools such as IDATA. It has been proved by experiments that this is a fast effective scalable and reconfigurable method of developing both actual equipment and simulators.

Design of virtual display and testing system for moving mass electromechanical actuator

NASA Astrophysics Data System (ADS)

Gao, Zhigang; Geng, Keda; Zhou, Jun; Li, Peng

2015-12-01

Aiming at the problem of control, measurement and movement virtual display of moving mass electromechanical actuator(MMEA), the virtual testing system of MMEA was developed based on the PC-DAQ architecture and the software platform of LabVIEW, and the comprehensive test task such as drive control of MMEA, tests of kinematic parameter, measurement of centroid position and virtual display of movement could be accomplished. The system could solve the alignment for acquisition time between multiple measurement channels in different DAQ cards, then on this basis, the researches were focused on the dynamic 3D virtual display by the LabVIEW, and the virtual display of MMEA were realized by the method of calling DLL and the method of 3D graph drawing controls. Considering the collaboration with the virtual testing system, including the hardware drive, the measurement software of data acquisition, and the 3D graph drawing controls method was selected, which could obtained the synchronization measurement, control and display. The system can measure dynamic centroid position and kinematic position of movable mass block while controlling the MMEA, and the interface of 3D virtual display has realistic effect and motion smooth, which can solve the problem of display and playback about MMEA in the closed shell.

Lunar laser ranging data processing in a Unix/X windows environment

NASA Technical Reports Server (NTRS)

Ricklefs, Randall L.; Ries, Judit G.

1993-01-01

In cooperation with the NASA Crustal Dynamics Project initiative placing workstation computers at each of its laser ranging stations to handle data filtering and normalpointing, MLRS personnel have developed a new generation of software to provide the same services for the lunar laser ranging data type. The Unix operating system and X windows/Motif provides an environment for both batch and interactive filtering and normalpointing as well as prediction calculations. The goal is to provide a transportable and maintainable data reduction environment. This software and some sample displays are presented. that the lunar (or satellite) datacould be processed on one computer while data was taken on the other. The reduction of the data was totally interactive and in no way automated. In addition, lunar predictions were produced on-site, another first in the effort to down-size historically mainframe-based applications. Extraction of earth rotation parameters was at one time attempted on site in near-realtime. In 1988, the Crustal Dynamics Project SLR Computer Panel mandated the installation of Hewlett-Packard 9000/360 Unix workstations at each NASA-operated laser ranging station to relieve the aging controller computers of much of their data and communications handling responsibility and to provide on-site data filtering and normal pointing for a growing list of artificial satellite targets. This was seen by MLRS staff as an opportunity to provide a better lunar data processing environment as well.

Lunar laser ranging data processing in a Unix/X windows environment

NASA Astrophysics Data System (ADS)

Ricklefs, Randall L.; Ries, Judit G.

1993-06-01

In cooperation with the NASA Crustal Dynamics Project initiative placing workstation computers at each of its laser ranging stations to handle data filtering and normalpointing, MLRS personnel have developed a new generation of software to provide the same services for the lunar laser ranging data type. The Unix operating system and X windows/Motif provides an environment for both batch and interactive filtering and normalpointing as well as prediction calculations. The goal is to provide a transportable and maintainable data reduction environment. This software and some sample displays are presented. that the lunar (or satellite) datacould be processed on one computer while data was taken on the other. The reduction of the data was totally interactive and in no way automated. In addition, lunar predictions were produced on-site, another first in the effort to down-size historically mainframe-based applications. Extraction of earth rotation parameters was at one time attempted on site in near-realtime. In 1988, the Crustal Dynamics Project SLR Computer Panel mandated the installation of Hewlett-Packard 9000/360 Unix workstations at each NASA-operated laser ranging station to relieve the aging controller computers of much of their data and communications handling responsibility and to provide on-site data filtering and normal pointing for a growing list of artificial satellite targets. This was seen by MLRS staff as an opportunity to provide a better lunar data processing environment as well.

Parallel replica dynamics with a heterogeneous distribution of barriers: Application to n-hexadecane pyrolysis

NASA Astrophysics Data System (ADS)

Kum, Oyeon; Dickson, Brad M.; Stuart, Steven J.; Uberuaga, Blas P.; Voter, Arthur F.

2004-11-01

Parallel replica dynamics simulation methods appropriate for the simulation of chemical reactions in molecular systems with many conformational degrees of freedom have been developed and applied to study the microsecond-scale pyrolysis of n-hexadecane in the temperature range of 2100-2500 K. The algorithm uses a transition detection scheme that is based on molecular topology, rather than energetic basins. This algorithm allows efficient parallelization of small systems even when using more processors than particles (in contrast to more traditional parallelization algorithms), and even when there are frequent conformational transitions (in contrast to previous implementations of the parallel replica algorithm). The parallel efficiency for pyrolysis initiation reactions was over 90% on 61 processors for this 50-atom system. The parallel replica dynamics technique results in reaction probabilities that are statistically indistinguishable from those obtained from direct molecular dynamics, under conditions where both are feasible, but allows simulations at temperatures as much as 1000 K lower than direct molecular dynamics simulations. The rate of initiation displayed Arrhenius behavior over the entire temperature range, with an activation energy and frequency factor of Ea=79.7 kcal/mol and log A/s-1=14.8, respectively, in reasonable agreement with experiment and empirical kinetic models. Several interesting unimolecular reaction mechanisms were observed in simulations of the chain propagation reactions above 2000 K, which are not included in most coarse-grained kinetic models. More studies are needed in order to determine whether these mechanisms are experimentally relevant, or specific to the potential energy surface used.

Two New Aircraft Traffic Surveillance Symbology Concepts: Range Filter and Inboard Field-of-View Symbology

NASA Technical Reports Server (NTRS)

Wong, Douglas T.; Kramer, Lynda J.; Norman, R. Michael

2001-01-01

The objective of this preliminary experiment was to investigate two head-up surveillance symbology (HUSS) display issues. The first issue was concerned with the benefits of adding a range filter to the current HUSS concept. A range filter limits the amount of traffic symbols displayed head-up by setting a range boundary (e.g., 7-nmi) around the ownship. The second issue was concerned with the need to incorporate HUSS in the inboard field-of-view (IFOV) display of the eXternal Visibility System (XVS) concept. The hypothesis tested was that adding a range filter to the XVS display and HUSS to the IFOV display would enhance the pilot's effectiveness in traffic surveillance tasks. Using a high-resolution graphics flight simulator, each of three pilots flew departure and arrival scenarios under visual meteorological conditions. The pilots' main tasks, while managing flight path, were to detect and assess potential airborne traffic hazards and to maintain overall situation awareness. Upon completing all the runs, each pilot completed a subjective questionnaire. Results showed that having both the HUSS on the IFOV and the range filter on each of the XVS displays enhanced the effectiveness of the XVS surveillance display concept. This configuration had the least head down time and the lowest mental workload. Combining both features gave the best target detection and, the earliest threat recognition performances, and enabled the pilots to create a better strategy for evasive action when it became necessary.

Carbon Nanotube Driver Circuit for 6 × 6 Organic Light Emitting Diode Display

PubMed Central

Zou, Jianping; Zhang, Kang; Li, Jingqi; Zhao, Yongbiao; Wang, Yilei; Pillai, Suresh Kumar Raman; Volkan Demir, Hilmi; Sun, Xiaowei; Chan-Park, Mary B.; Zhang, Qing

2015-01-01

Single-walled carbon nanotube (SWNT) is expected to be a very promising material for flexible and transparent driver circuits for active matrix organic light emitting diode (AM OLED) displays due to its high field-effect mobility, excellent current carrying capacity, optical transparency and mechanical flexibility. Although there have been several publications about SWNT driver circuits, none of them have shown static and dynamic images with the AM OLED displays. Here we report on the first successful chemical vapor deposition (CVD)-grown SWNT network thin film transistor (TFT) driver circuits for static and dynamic AM OLED displays with 6 × 6 pixels. The high device mobility of ~45 cm2V−1s−1 and the high channel current on/off ratio of ~105 of the SWNT-TFTs fully guarantee the control capability to the OLED pixels. Our results suggest that SWNT-TFTs are promising backplane building blocks for future OLED displays. PMID:26119218

Comparative community-level associations of helminth infections and microparasite shedding in wild long-tailed macaques in Bali, Indonesia.

PubMed

Wilcox, Justin J S; Lane-Degraaf, Kelly E; Fuentes, Agustin; Hollocher, Hope

2015-03-01

Helminthes have the capacity to modulate host immunity, leading to positive interactions with coinfecting microparasites. This phenomenon has been primarily studied during coinfections with a narrow range of geo-helminthes and intracellular microparasites in human populations or under laboratory conditions. Far less is known regarding differences in coinfection dynamics between helminth types, the range of microparasites that might be affected or the overall community-level effects of helminth infections on microparasites in wild systems. Here, we analysed the presence/absence and abundance patterns of enteric parasites in long-tailed macaques (Macaca fascicularis) on the island of Bali, Indonesia, to assess whether naturally occurring helminth infections were associated with increased shedding of the most common intracellular (Cryptosporidium spp., Isospora spp.) and extracellular (Entamoeba spp., Giardia spp.) microparasites. We also comparatively assessed the statistical correlations of different helminth taxa with microparasite shedding to determine if there were consistent relationships between the specific helminth taxa and microparasites. Helminth infections were associated with increased shedding of both intracellular and extracellular microparasites. Platyhelminthes repeatedly displayed strong positive correlations with several microparasites; while nematodes did not. Our results indicate that helminthes can influence microparasite community shedding dynamics under wild conditions, but that trends may be driven by a narrow range of helminthes.

Cross-Cultural Patterns in Dynamic Ratings of Positive and Negative Natural Emotional Behaviour

PubMed Central

Sneddon, Ian; McKeown, Gary; McRorie, Margaret; Vukicevic, Tijana

2011-01-01

Background Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli. Methodology/Principal Findings Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips. Conclusions/Significance The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both ‘in-group advantage’ and ‘display rules’ approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion. PMID:21364739

Cross-cultural patterns in dynamic ratings of positive and negative natural emotional behaviour.

PubMed

Sneddon, Ian; McKeown, Gary; McRorie, Margaret; Vukicevic, Tijana

2011-02-18

Studies of cross-cultural variations in the perception of emotion have typically compared rates of recognition of static posed stimulus photographs. That research has provided evidence for universality in the recognition of a range of emotions but also for some systematic cross-cultural variation in the interpretation of emotional expression. However, questions remain about how widely such findings can be generalised to real life emotional situations. The present study provides the first evidence that the previously reported interplay between universal and cultural influences extends to ratings of natural, dynamic emotional stimuli. Participants from Northern Ireland, Serbia, Guatemala and Peru used a computer based tool to continuously rate the strength of positive and negative emotion being displayed in twelve short video sequences by people from the United Kingdom engaged in emotional conversations. Generalized additive mixed models were developed to assess the differences in perception of emotion between countries and sexes. Our results indicate that the temporal pattern of ratings is similar across cultures for a range of emotions and social contexts. However, there are systematic differences in intensity ratings between the countries, with participants from Northern Ireland making the most extreme ratings in the majority of the clips. The results indicate that there is strong agreement across cultures in the valence and patterns of ratings of natural emotional situations but that participants from different cultures show systematic variation in the intensity with which they rate emotion. Results are discussed in terms of both 'in-group advantage' and 'display rules' approaches. This study indicates that examples of natural spontaneous emotional behaviour can be used to study cross-cultural variations in the perception of emotion.

Commemorative Displays: Bridging the Gap Between Past and Present.

ERIC Educational Resources Information Center

Stock, John T.

1984-01-01

Suggests preparing displays which include both dynamic and static items to attract observers' attention and hold their interest. Includes instructions for making exhibits related to phenomena associated with Joseph Priestley and Michael Faraday. (DH)

Thermal and Denaturation Studies of the Time-Resolved Fluorescence Decay of Human Superoxide Dismutase

NASA Astrophysics Data System (ADS)

Silva, Norberto De Jesus

Previous studies have shown that time-resolved fluorescence decay of various single tryptophan proteins is best described by a distribution of fluorescence lifetimes rather than one or two lifetimes. The thermal dependence of the lifetime distributions is consistent with the hypothesis that proteins fluctuate between a hierarchy of many conformational substates. With this scenario as a theoretical framework, the correlations between protein dynamic and structure are investigated by studying the time-resolved fluorescence and anisotropy decay of the single tryptophan (Trp) residue of human superoxide dismutase (HSOD) over a wide range of temperatures and at different denaturant concentrations. First, it is demonstrated that the center of the lifetime distribution can characterize the average deactivation environment of the excited Trp-protein system. A qualitative model is introduced to explain the time-resolved fluorescence decay of HSOD in 80% glycerol over a wide range of temperatures. The dynamical model features isoenergetic conformational substates separated by a hierarchy of energy barriers. The HSOD system is also investigated as a function of denaturant concentration in aqueous solution. As a function of guanidine hydrochloride (GdHCl), the width of the fluorescence lifetime distribution of HSOD displays a maximum which is not coincident with the fully denatured form of HSOD at 6.5M GdHCl. Furthermore, the width for the fully denatured form of HSOD is greater than that of the native form. This is consistent with the scenario that more conformational substates are being created upon denaturation of HSOD. HSOD is a dimeric protein and it was observed that the width of the lifetime distribution of HSOD at intermediate GdHCl concentrations increased with decreasing protein concentration. In addition, the secondary structure of HSOD at intermediate GdHCl concentration does not change with protein concentration. These results suggest that HSOD display structural microheterogeneity which is consistent with the hypothesis of conformational substates. Further analysis show that, during denaturation, the monomeric form of HSOD is an intermediate which displays native-like secondary structure and fluctuating tertiary structure; i.e., the monomeric form of HSOD is a molten globule.

Intelligent Weather Agent

NASA Technical Reports Server (NTRS)

Spirkovska, Liljana (Inventor)

2006-01-01

Method and system for automatically displaying, visually and/or audibly and/or by an audible alarm signal, relevant weather data for an identified aircraft pilot, when each of a selected subset of measured or estimated aviation situation parameters, corresponding to a given aviation situation, has a value lying in a selected range. Each range for a particular pilot may be a default range, may be entered by the pilot and/or may be automatically determined from experience and may be subsequently edited by the pilot to change a range and to add or delete parameters describing a situation for which a display should be provided. The pilot can also verbally activate an audible display or visual display of selected information by verbal entry of a first command or a second command, respectively, that specifies the information required.

Display interface concepts for automated fault diagnosis

NASA Technical Reports Server (NTRS)

Palmer, Michael T.

1989-01-01

An effort which investigated concepts for displaying dynamic system status and fault history (propagation) information to the flight crew is described. This investigation was performed by developing several candidate display formats and then conducting comprehension tests to determine those characteristics that made one format preferable to another for presenting this type of information. Twelve subjects participated. Flash tests, or limited time exposure tests, were used to determine the subjects' comprehension of the information presented in the display formats. It was concluded from the results of the comprehension tests that pictographs were more comprehensible than both block diagrams and text for presenting dynamic system status and fault history information, and that pictographs were preferred over both block diagrams and text. It was also concluded that the addition of this type of information in the cockpit would help the crew remain aware of the status of their aircraft.

Distribution of chaos and periodic spikes in a three-cell population model of cancer. Auto-organization of oscillatory phases in parameter planes

NASA Astrophysics Data System (ADS)

Gallas, Michelle R.; Gallas, Marcia R.; Gallas, Jason A. C.

2014-10-01

We study complex oscillations generated by the de Pillis-Radunskaya model of cancer growth, a model including interactions between tumor cells, healthy cells, and activated immune system cells. We report a wide-ranging systematic numerical classification of the oscillatory states and of their relative abundance. The dynamical states of the cell populations are characterized here by two independent and complementary types of stability diagrams: Lyapunov and isospike diagrams. The model is found to display stability phases organized regularly in old and new ways: Apart from the familiar spirals of stability, it displays exceptionally long zig-zag networks and intermixed cascades of two- and three-doubling flanked stability islands previously detected only in feedback systems with delay. In addition, we also characterize the interplay between continuous spike-adding and spike-doubling mechanisms responsible for the unbounded complexification of periodic wave patterns. This article is dedicated to Prof. Hans Jürgen Herrmann on the occasion of his 60th birthday.

Rendering of HDR content on LDR displays: an objective approach

NASA Astrophysics Data System (ADS)

Krasula, Lukáš; Narwaria, Manish; Fliegel, Karel; Le Callet, Patrick

2015-09-01

Dynamic range compression (or tone mapping) of HDR content is an essential step towards rendering it on traditional LDR displays in a meaningful way. This is however non-trivial and one of the reasons is that tone mapping operators (TMOs) usually need content-specific parameters to achieve the said goal. While subjective TMO parameter adjustment is the most accurate, it may not be easily deployable in many practical applications. Its subjective nature can also influence the comparison of different operators. Thus, there is a need for objective TMO parameter selection to automate the rendering process. To that end, we investigate into a new objective method for TMO parameters optimization. Our method is based on quantification of contrast reversal and naturalness. As an important advantage, it does not require any prior knowledge about the input HDR image and works independently on the used TMO. Experimental results using a variety of HDR images and several popular TMOs demonstrate the value of our method in comparison to default TMO parameter settings.

Non-identical multiplexing promotes chimera states

NASA Astrophysics Data System (ADS)

Ghosh, Saptarshi; Zakharova, Anna; Jalan, Sarika

2018-01-01

We present the emergence of chimeras, a state referring to coexistence of partly coherent, partly incoherent dynamics in networks of identical oscillators, in a multiplex network consisting of two non-identical layers which are interconnected. We demonstrate that the parameter range displaying the chimera state in the homogeneous first layer of the multiplex networks can be tuned by changing the link density or connection architecture of the same nodes in the second layer. We focus on the impact of the interconnected second layer on the enlargement or shrinking of the coupling regime for which chimeras are displayed in the homogeneous first layer. We find that a denser homogeneous second layer promotes chimera in a sparse first layer, where chimeras do not occur in isolation. Furthermore, while a dense connection density is required for the second layer if it is homogeneous, this is not true if the second layer is inhomogeneous. We demonstrate that a sparse inhomogeneous second layer which is common in real-world complex systems can promote chimera states in a sparse homogeneous first layer.

Solid-liquid and liquid-solid transitions in metal nanoparticles.

PubMed

Hou, M

2017-02-22

The melting and solidification temperatures of nanosystems may differ by several hundred Kelvin. To understand the origin of this difference, transitions in small metallic nanoparticles on the atomic scale were analyzed using molecular dynamics (MD). Palladium was used as a case study, which was then extended to a range of other elemental metals. It was argued that in realistic environments, such as gases at low pressure (of the order of 1 mbar), heat transfers allow the microcanonical thermal equilibrium evolution of the nanoparticles between successive collisions with gas atoms. This is shown to have no significant influence on the mechanism of melting, whereas in an isolated nanoparticle, solidification triggers a huge and rapid increase in temperature. A simple relationship between the melting and solidification temperatures was found, indicating that the magnitude of the latent heat of melting governs undercooling. Whereas melting occurs via heterogeneous nucleation, solidification displays characteristics of spinodal decomposition. Consistently, the melting temperature scales with the surface-to-volume ratio, whereas the solidification temperature displays no significant dependence on the particle size.

Relating Standardized Visual Perception Measures to Simulator Visual System Performance

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.; Sweet, Barbara T.

2013-01-01

Human vision is quantified through the use of standardized clinical vision measurements. These measurements typically include visual acuity (near and far), contrast sensitivity, color vision, stereopsis (a.k.a. stereo acuity), and visual field periphery. Simulator visual system performance is specified in terms such as brightness, contrast, color depth, color gamut, gamma, resolution, and field-of-view. How do these simulator performance characteristics relate to the perceptual experience of the pilot in the simulator? In this paper, visual acuity and contrast sensitivity will be related to simulator visual system resolution, contrast, and dynamic range; similarly, color vision will be related to color depth/color gamut. Finally, we will consider how some characteristics of human vision not typically included in current clinical assessments could be used to better inform simulator requirements (e.g., relating dynamic characteristics of human vision to update rate and other temporal display characteristics).

Cluster adsorption on amorphous and crystalline surfaces - A molecular dynamics study of model Pt on Cu and model Pd on Pt

NASA Technical Reports Server (NTRS)

Garofalini, S. H.; Halicioglu, T.; Pound, G. M.

1981-01-01

Molecular dynamics was used to study the structure, dispersion and short-time behavior of ten-atom clusters adsorbed onto amorphous and crystalline substrates, in which the cluster atoms differed from the substrate atoms. Two adatom-substrate model systems were chosen; one, in which the interaction energy between adatom pairs was greater than that between substrate pairs, and the other, in which the reverse was true. At relatively low temperature ranges, increased dispersion of cluster atoms occurred: (a) on the amorphous substrate as compared to the FCC(100) surface, (b) with increasing reduced temperature, and (c) with adatom-substrate interaction energy stronger than adatom-adatom interaction. Two-dimensional clusters (rafts) on the FCC(100) surface displayed migration of edge atoms only, indicating a mechanism for the cluster rotation and shape changes found in experimental studies.

Molecular Dynamics Simulations of Carbon Nanotubes in Water

NASA Technical Reports Server (NTRS)

Walther, J. H.; Jaffe, R.; Halicioglu, T.; Koumoutsakos, P.

2000-01-01

We study the hydrophobic/hydrophilic behavior of carbon nanotubes using molecular dynamics simulations. The energetics of the carbon-water interface are mainly dispersive but in the present study augmented with a carbon quadrupole term acting on the charge sites of the water. The simulations indicate that this contribution is negligible in terms of modifying the structural properties of water at the interface. Simulations of two carbon nanotubes in water display a wetting and drying of the interface between the nanotubes depending on their initial spacing. Thus, initial tube spacings of 7 and 8 A resulted in a drying of the interface whereas spacing of > 9 A remain wet during the course of the simulation. Finally, we present a novel particle-particle-particle-mesh algorithm for long range potentials which allows for general (curvilinear) meshes and "black-box" fast solvers by adopting an influence matrix technique.

Modeling the structural, dynamical, and magnetic properties of liquid Al1-xMnx ( x=0.14 , 0.2, and 0.4): A first-principles investigation

NASA Astrophysics Data System (ADS)

Jakse, N.; Pasturel, A.

2007-07-01

We report the results of first-principles molecular dynamics simulations of liquid Al1-xMnx alloys at three different compositions. The local structure as defined by the Bhatia-Thornton partial structure factors is found to display significant changes at x=0.4 . In addition, a structural analysis using three-dimensional pair-analysis techniques evidences a fivefold symmetry around x=0.14 , in agreement with the experimental quasicrystal-forming range, and an increasing complexity of the Frank-Kasper polytetrahedral symmetry around Mn atoms at x=0.4 . We also examine the time evolution of the configurations at the three compositions in terms of the mean-square displacements and self-diffusion coefficients. Finally, we show a strong interplay between the structural changes and the evolution of the magnetic properties of the Mn atoms as a function of composition.

Classical simulation of quantum error correction in a Fibonacci anyon code

NASA Astrophysics Data System (ADS)

Burton, Simon; Brell, Courtney G.; Flammia, Steven T.

2017-02-01

Classically simulating the dynamics of anyonic excitations in two-dimensional quantum systems is likely intractable in general because such dynamics are sufficient to implement universal quantum computation. However, processes of interest for the study of quantum error correction in anyon systems are typically drawn from a restricted class that displays significant structure over a wide range of system parameters. We exploit this structure to classically simulate, and thereby demonstrate the success of, an error-correction protocol for a quantum memory based on the universal Fibonacci anyon model. We numerically simulate a phenomenological model of the system and noise processes on lattice sizes of up to 128 ×128 sites, and find a lower bound on the error-correction threshold of approximately 0.125 errors per edge, which is comparable to those previously known for Abelian and (nonuniversal) non-Abelian anyon models.

A Flight Dynamics Perspective of the Orion Pad Abort One Flight Test

NASA Technical Reports Server (NTRS)

Idicula, Jinu; Williams-Hayes, Peggy S.; Stillwater, Ryan; Yates, Max

2009-01-01

The Orion Crew Exploration Vehicle is America s next generation of human rated spacecraft. The Orion Launch Abort System will take the astronauts away from the exploration vehicle in the event of an aborted launch. The pad abort mode of the Launch Abort System will be flight-tested in 2009 from the White Sands Missile Range in New Mexico. This paper examines some of the efforts currently underway at the NASA Dryden Flight Research Center by the Controls & Dynamics group in preparation for the flight test. The concept of operation for the pad abort flight is presented along with an overview of the guidance, control and navigation systems. Preparations for the flight test, such as hardware testing and development of the real-time displays, are examined. The results from the validation and verification efforts for the aerodynamic and atmospheric models are shown along with Monte Carlo analysis results.

Interactive information processing for NASA's mesoscale analysis and space sensor program

NASA Technical Reports Server (NTRS)

Parker, K. G.; Maclean, L.; Reavis, N.; Wilson, G.; Hickey, J. S.; Dickerson, M.; Karitani, S.; Keller, D.

1985-01-01

The Atmospheric Sciences Division (ASD) of the Systems Dynamics Laboratory at NASA's Marshall Space Flight Center (MSFC) is currently involved in interactive information processing for the Mesoscale Analysis and Space Sensor (MASS) program. Specifically, the ASD is engaged in the development and implementation of new space-borne remote sensing technology to observe and measure mesoscale atmospheric processes. These space measurements and conventional observational data are being processed together to gain an improved understanding of the mesoscale structure and the dynamical evolution of the atmosphere relative to cloud development and precipitation processes. To satisfy its vast data processing requirements, the ASD has developed a Researcher Computer System consiting of three primary computer systems which provides over 20 scientists with a wide range of capabilities for processing and displaying a large volumes of remote sensing data. Each of the computers performs a specific function according to its unique capabilities.

Fiber-optic three axis magnetometer prototype development

NASA Technical Reports Server (NTRS)

Wang, Thomas D.; Mccomb, David G.; Kingston, Bradley R.; Dube, C. Michael; Poehls, Kenneth A.; Wanser, Keith

1989-01-01

The goal of this research program was to develop a high sensitivity, fiber optic, interferometric, three-axis magnetometer for interplanetary spacecraft applications. Dynamics Technology, Inc. (DTI) has successfully integrated a low noise, high bandwidth interferometer with high sensitivity metallic glass transducers. Also, DTI has developed sophisticated signal processing electronics and complete data acquisition, filtering, and display software. The sensor was packaged in a compact, low power and weight unit which facilitates deployment. The magnetic field sensor had subgamma sensitivity and a dynamic range of 10(exp 5) gamma in a 10 Hz bandwidth. Furthermore, the vector instrument exhibited the lowest noise level when only one axis was in operation. A system noise level of 1 gamma rms was observed in a 1 Hz bandwidth. However, with the other two channels operating, the noise level increased by about one order of magnitude. Higher system noise was attributed to cross-channel interference among the dither fields.

Dynamic traffic assignment based trailblazing guide signing for major traffic generator.

DOT National Transportation Integrated Search

2009-11-01

The placement of guide signs and the display of dynamic massage signs greatly affect drivers : understanding of the network and therefore their route choices. Most existing dynamic traffic assignment : models assume that drivers heading to a Major...

Seeing the Song: Left Auditory Structures May Track Auditory-Visual Dynamic Alignment

PubMed Central

Mossbridge, Julia A.; Grabowecky, Marcia; Suzuki, Satoru

2013-01-01

Auditory and visual signals generated by a single source tend to be temporally correlated, such as the synchronous sounds of footsteps and the limb movements of a walker. Continuous tracking and comparison of the dynamics of auditory-visual streams is thus useful for the perceptual binding of information arising from a common source. Although language-related mechanisms have been implicated in the tracking of speech-related auditory-visual signals (e.g., speech sounds and lip movements), it is not well known what sensory mechanisms generally track ongoing auditory-visual synchrony for non-speech signals in a complex auditory-visual environment. To begin to address this question, we used music and visual displays that varied in the dynamics of multiple features (e.g., auditory loudness and pitch; visual luminance, color, size, motion, and organization) across multiple time scales. Auditory activity (monitored using auditory steady-state responses, ASSR) was selectively reduced in the left hemisphere when the music and dynamic visual displays were temporally misaligned. Importantly, ASSR was not affected when attentional engagement with the music was reduced, or when visual displays presented dynamics clearly dissimilar to the music. These results appear to suggest that left-lateralized auditory mechanisms are sensitive to auditory-visual temporal alignment, but perhaps only when the dynamics of auditory and visual streams are similar. These mechanisms may contribute to correct auditory-visual binding in a busy sensory environment. PMID:24194873

Case study: the introduction of stereoscopic games on the Sony PlayStation 3

NASA Astrophysics Data System (ADS)

Bickerstaff, Ian

2012-03-01

A free stereoscopic firmware update on Sony Computer Entertainment's PlayStation® 3 console provides the potential to increase enormously the popularity of stereoscopic 3D in the home. For this to succeed though, a large selection of content has to become available that exploits 3D in the best way possible. In addition to the existing challenges found in creating 3D movies and television programmes, the stereography must compensate for the dynamic and unpredictable environments found in games. Automatically, the software must map the depth range of the scene into the display's comfort zone, while minimising depth compression. This paper presents a range of techniques developed to solve this problem and the challenge of creating twice as many images as the 2D version without excessively compromising the frame rate or image quality. At the time of writing, over 80 stereoscopic PlayStation 3 games have been released and notable titles are used as examples to illustrate how the techniques have been adapted for different game genres. Since the firmware's introduction in 2010, the industry has matured with a large number of developers now producing increasingly sophisticated 3D content. New technologies such as viewer head tracking and head-mounted displays should increase the appeal of 3D in the home still further.

Prediction and measurement of human pilot dynamic characteristics

NASA Technical Reports Server (NTRS)

Hess, Ronald A.; Reedy, James T.

1988-01-01

An analytical and experimental study of human pilot control strategies in a manned rotorcraft simulation is described. The task simulated involves a low-speed, constant-altitude maneuvering task in which a head-down display is utilized to allow the pilot to track a moving hover point. The efficacy of the display law driving an 'acceleration symbol' is determined and the manner in which the prediction and measurement of pilot/vehicle dynamics can be made part of man/machine system evaluations is demonstrated.

ASSESSING THE EFFECTS OF PULMONARY EXPOSURE TO NANOMATERIALS

EPA Science Inventory

Nanotechnology is a dynamic and enabling technology capable of producing a wide diversity of nano-scale (<100 nm) materials displaying unique physicochemical properties for a variety of applications. Nanomaterials may also display unique toxicological properties and routes of exp...

Structural and dynamic changes associated with beneficial engineered single-amino-acid deletion mutations in enhanced green fluorescent protein

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

Arpino, James A. J.; Rizkallah, Pierre J., E-mail: rizkallahp@cardiff.ac.uk; Jones, D. Dafydd, E-mail: rizkallahp@cardiff.ac.uk

2014-08-01

The beneficial engineered single-amino-acid deletion variants EGFP{sup D190Δ} and EGFP{sup A227Δ} have been studied. Single-amino-acid deletions are a common part of the natural evolutionary landscape but are rarely sampled during protein engineering owing to limited and prejudiced molecular understanding of mutations that shorten the protein backbone. Single-amino-acid deletion variants of enhanced green fluorescent protein (EGFP) have been identified by directed evolution with the beneficial effect of imparting increased cellular fluorescence. Biophysical characterization revealed that increased functional protein production and not changes to the fluorescence parameters was the mechanism that was likely to be responsible. The structure EGFP{sup D190Δ} containing amore » deletion within a loop revealed propagated changes only after the deleted residue. The structure of EGFP{sup A227Δ} revealed that a ‘flipping’ mechanism was used to adjust for residue deletion at the end of a β-strand, with amino acids C-terminal to the deletion site repositioning to take the place of the deleted amino acid. In both variants new networks of short-range and long-range interactions are generated while maintaining the integrity of the hydrophobic core. Both deletion variants also displayed significant local and long-range changes in dynamics, as evident by changes in B factors compared with EGFP. Rather than being detrimental, deletion mutations can introduce beneficial structural effects through altering core protein properties, folding and dynamics, as well as function.« less

Nonlinear coherent optical image processing using logarithmic transmittance of bacteriorhodopsin films

NASA Astrophysics Data System (ADS)

Downie, John D.

1995-08-01

The transmission properties of some bacteriorhodopsin-film spatial light modulators are uniquely suited to allow nonlinear optical image-processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude-transmission characteristic of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. I present experimental results demonstrating the principle and the capability for several different image and noise situations, including deterministic noise and speckle. The bacteriorhodopsin film studied here displays the logarithmic transmission response for write intensities spanning a dynamic range greater than 2 orders of magnitude.

Acoustic emission study of deformation behavior of nacre

NASA Astrophysics Data System (ADS)

Luo, Shunfei; Luo, Hongyun; Han, Zhiyuan

2016-02-01

A study on the acoustic emission (AE) characteristics during deformation of nacre material was performed. We found that intermittent AE events are generated during nacre deformation. These avalanches may be attributed to microfracture events of the aragonite (CaCO3) nano-asperities and bridges during tablet sliding. These events show several critical features, such as the power-law distributions of the avalanche sizes and interval. These results suggest that the underlying fracture dynamics during nacre deformation display a self-organized criticality (SOC). The results also imply that the disorder and long-range correlation between local microfracture events may play important roles in nacre deformation.

Nonlinear Coherent Optical Image Processing Using Logarithmic Transmittance of Bacteriorhodopsin Films

NASA Technical Reports Server (NTRS)

Downie, John D.

1995-01-01

The transmission properties of some bacteriorhodopsin-film spatial light modulators are uniquely suited to allow nonlinear optical image-processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude-transmission characteristic of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. I present experimental results demonstrating the principle and the capability for several different image and noise situations, including deterministic noise and speckle. The bacteriorhodopsin film studied here displays the logarithmic transmission response for write intensities spanning a dynamic range greater than 2 orders of magnitude.

Chimera Type Behavior in Nonlocal Coupling System with Two Different Inherent Frequencies

NASA Astrophysics Data System (ADS)

Lin, Larry; Li, Ping-Cheng; Tseng, Hseng-Che

2014-03-01

From the research of Kuramoto and Strogatz, arrays of identical oscillators can display a remarkable pattern, named chimera state, in which phase-locked oscillators coexist with drifting ones in nonlocal coupling oscillator system. We consider further in this study, two groups of oscillators with different inherent frequencies and arrange them in a ring. When the difference of the inherent frequencies is within some specific parameter range, oscillators of nonlocal coupling system show two distinct chimera states. When the parameter value exceeds some threshold value, two chimera states disappear. They show different features. The statistical dynamic behavior of the system can be described by Kuramoto theory.

Crossover transition in the fluctuation of Internet

NASA Astrophysics Data System (ADS)

Qian, Jiang-Hai

2018-06-01

The inconsistent fluctuation behavior of Internet predicted by preferential attachment(PA) and Gibrat's law requires empirical investigations on the actual system. By using the interval-tunable Gibrat's law statistics, we find the actual fluctuation, characterized by the conditional standard deviation of the degree growth rate, changes with the interval length and displays a crossover transition from PA type to Gibrat's law type, which has not yet been captured by any previous models. We characterize the transition dynamics quantitatively and determine the applicative range of PA and Gibrat's law. The correlation analysis indicates the crossover transition may be attributed to the accumulative correlation between the internal links.

The robot's eyes - Stereo vision system for automated scene analysis

NASA Technical Reports Server (NTRS)

Williams, D. S.

1977-01-01

Attention is given to the robot stereo vision system which maintains the image produced by solid-state detector television cameras in a dynamic random access memory called RAPID. The imaging hardware consists of sensors (two solid-state image arrays using a charge injection technique), a video-rate analog-to-digital converter, the RAPID memory, and various types of computer-controlled displays, and preprocessing equipment (for reflexive actions, processing aids, and object detection). The software is aimed at locating objects and transversibility. An object-tracking algorithm is discussed and it is noted that tracking speed is in the 50-75 pixels/s range.

Molecular dynamics simulations through GPU video games technologies

PubMed Central

Loukatou, Styliani; Papageorgiou, Louis; Fakourelis, Paraskevas; Filntisi, Arianna; Polychronidou, Eleftheria; Bassis, Ioannis; Megalooikonomou, Vasileios; Makałowski, Wojciech; Vlachakis, Dimitrios; Kossida, Sophia

2016-01-01

Bioinformatics is the scientific field that focuses on the application of computer technology to the management of biological information. Over the years, bioinformatics applications have been used to store, process and integrate biological and genetic information, using a wide range of methodologies. One of the most de novo techniques used to understand the physical movements of atoms and molecules is molecular dynamics (MD). MD is an in silico method to simulate the physical motions of atoms and molecules under certain conditions. This has become a state strategic technique and now plays a key role in many areas of exact sciences, such as chemistry, biology, physics and medicine. Due to their complexity, MD calculations could require enormous amounts of computer memory and time and therefore their execution has been a big problem. Despite the huge computational cost, molecular dynamics have been implemented using traditional computers with a central memory unit (CPU). A graphics processing unit (GPU) computing technology was first designed with the goal to improve video games, by rapidly creating and displaying images in a frame buffer such as screens. The hybrid GPU-CPU implementation, combined with parallel computing is a novel technology to perform a wide range of calculations. GPUs have been proposed and used to accelerate many scientific computations including MD simulations. Herein, we describe the new methodologies developed initially as video games and how they are now applied in MD simulations. PMID:27525251

Effect of Harm Anchors in Visual Displays of Test Results on Patient Perceptions of Urgency About Near-Normal Values: Experimental Study.

PubMed

Zikmund-Fisher, Brian J; Scherer, Aaron M; Witteman, Holly O; Solomon, Jacob B; Exe, Nicole L; Fagerlin, Angela

2018-03-26

Patient-facing displays of laboratory test results typically provide patients with one reference point (the "standard range"). To test the effect of including an additional harm anchor reference point in visual displays of laboratory test results, which indicates how far outside of the standard range values would need to be in order to suggest substantial patient risk. Using a demographically diverse, online sample, we compared the reactions of 1618 adults in the United States who viewed visual line displays that included both standard range and harm anchor reference points ("Many doctors are not concerned until here") to displays that included either (1) only a standard range, (2) standard range plus evaluative categories (eg, "borderline high"), or (3) a color gradient showing degree of deviation from the standard range. Providing the harm anchor reference point significantly reduced perceived urgency of close-to-normal alanine aminotransferase and creatinine results (P values <.001) but not generally for platelet count results. Notably, display type did not significantly alter perceptions of more extreme results in potentially harmful ranges. Harm anchors also substantially reduced the number of participants who wanted to contact their doctor urgently or go to the hospital about these test results. Presenting patients with evaluative cues regarding when test results become clinically concerning can reduce the perceived urgency of out-of-range results that do not require immediate clinical action. ©Brian J Zikmund-Fisher, Aaron M Scherer, Holly O Witteman, Jacob B Solomon, Nicole L Exe, Angela Fagerlin. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 26.03.2018.

DDML Schema Validation

DTIC Science & Technology

2016-02-08

Data Display Markup Language HUD heads-up display IRIG Inter-Range Instrumentation Group RCC Range Commanders Council SVG Scalable Vector Graphics...T&E test and evaluation TMATS Telemetry Attributes Transfer Standard XML eXtensible Markup Language DDML Schema Validation, RCC 126-16, February...2016 viii This page intentionally left blank. DDML Schema Validation, RCC 126-16, February 2016 1 1. Introduction This Data Display Markup

Time scale of dynamic heterogeneity in model ionic liquids and its relation to static length scale and charge distribution.

PubMed

Park, Sang-Won; Kim, Soree; Jung, YounJoon

2015-11-21

We study how dynamic heterogeneity in ionic liquids is affected by the length scale of structural relaxation and the ionic charge distribution by the molecular dynamics simulations performed on two differently charged models of ionic liquid and their uncharged counterpart. In one model of ionic liquid, the charge distribution in the cation is asymmetric, and in the other it is symmetric, while their neutral counterpart has no charge with the ions. It is found that all the models display heterogeneous dynamics, exhibiting subdiffusive dynamics and a nonexponential decay of structural relaxation. We investigate the lifetime of dynamic heterogeneity, τ(dh), in these systems by calculating the three-time correlation functions to find that τ(dh) has in general a power-law behavior with respect to the structural relaxation time, τ(α), i.e., τ(dh) ∝ τ(α)(ζ(dh)). Although the dynamics of the asymmetric-charge model is seemingly more heterogeneous than that of the symmetric-charge model, the exponent is found to be similar, ζ(dh) ≈ 1.2, for all the models studied in this work. The same scaling relation is found regardless of interactions, i.e., with or without Coulomb interaction, and it holds even when the length scale of structural relaxation is long enough to become the Fickian diffusion. This fact indicates that τ(dh) is a distinctive time scale from τ(α), and the dynamic heterogeneity is mainly affected by the short-range interaction and the molecular structure.

Two Aircraft Head-Up Traffic Surveillance Symbology Issues: Range Filter and Inboard Field-of-View Symbology

NASA Technical Reports Server (NTRS)

Wong, Douglas T.; Kramer, Lynda J.; Norman, R. Michael

2004-01-01

The purpose of the eXternal Visibility System (XVS) effort for NASA s High-Speed Research Program was to determine and to provide required pilot visual information for a High Speed Civil Transport vehicle concept to allow safe and efficient operation in the absence of forward windows. The objective of this preliminary experiment conducted at NASA Langley Research Center was to investigate two head-up surveillance symbology (HUSS) display issues. The first issue was concerned with the benefits of adding a range filter to the current HUSS concept. A range filter limits the amount of traffic symbols displayed head-up by setting a range boundary (e.g. 7-nmi) around the ownship. The second issue was concerned with the need to incorporate HUSS in the inboard field-of-view (IFOV) display of the XVS concept. The hypothesis tested was that adding a range filter to the XVS display and HUSS to the IFOV display would enhance the pilot s effectiveness of traffic surveillance tasks. Using a high-resolution graphics flight simulator, each of three pilots flew departure and arrival scenarios under visual meteorological conditions. The pilots main tasks, while managing flight path, were to detect and assess potential airborne traffic hazards and to maintain overall situation awareness. Upon completing all the runs, each pilot completed a subjective questionnaire. Results showed that having both the HUSS on the IFOV and the range filter on each of the XVS displays enhanced the effectiveness of the XVS surveillance display concept. This configuration had the least head down time and the lowest mental workload. Combining both features gave the best target detection, the earliest threat recognition, and enabled the pilots to create a better strategy for evasive action when it became necessary.

From global scaling to the dynamics of individual cities

NASA Astrophysics Data System (ADS)

Depersin, Jules; Barthelemy, Marc

2018-03-01

Scaling has been proposed as a powerful tool to analyze the properties of complex systems and in particular for cities where it describes how various properties change with population. The empirical study of scaling on a wide range of urban datasets displays apparent nonlinear behaviors whose statistical validity and meaning were recently the focus of many debates. We discuss here another aspect, which is the implication of such scaling forms on individual cities and how they can be used for predicting the behavior of a city when its population changes. We illustrate this discussion in the case of delay due to traffic congestion with a dataset of 101 US cities in the years 1982–2014. We show that the scaling form obtained by agglomerating all of the available data for different cities and for different years does display a nonlinear behavior, but which appears to be unrelated to the dynamics of individual cities when their population grows. In other words, the congestion-induced delay in a given city does not depend on its population only, but also on its previous history. This strong path dependency prohibits the existence of a simple scaling form valid for all cities and shows that we cannot always agglomerate the data for many different systems. More generally, these results also challenge the use of transversal data for understanding longitudinal series for cities.

Pilot stereotypes for navigation symbols on electronic displays

DOT National Transportation Integrated Search

2006-09-20

There is currently no common symbology standard for the : electronic display of navigation information. The wide : range of display technologies and the different functions : these displays support make it difficult to design symbols : that are easil...

Courtship display dynamics, iridescent structural color and nanostructural pattern formation in ocellated pheasants

NASA Astrophysics Data System (ADS)

Kane, Suzanne Amador; Dakin, Roslyn; Fang, Rui; Lu, Yabin

Peacocks court females by tilting a fan-like array of feathers decorated with multicolored eyespots (ocelli). Previous research has shown that half of the variation in peacock mating success can be attributed to eyespot iridescence. Several closely-related pheasant species perform similar, but less complex, courtship displays using ocellated feathers with less complex coloration, patterns and underlying nanostructures. This study explores the relationship between the dynamics of male courtship behavior and optical properties and nanostructure of each species' iridescent feather ornaments. In particular, we examined videos of courting males and of individual feathers to measure how the angles used during displays compared to those corresponding to optimal eyespot reflected intensity and iridescent contrast. Bidirectional reflectance spectroscopy was used to measure how the spectrum of reflected light depends on the characteristic angles used during displays, and hence how displays stimulate the four classes of cones found in the color vision systems of these birds. This work reveals a close correlation between the complexity of the angular dependence of iridescent feather reflectance properties and that of the motions used by males of each species.

Nutrient dynamics as indicators of karst processes: Comparison of the Chalk aquifer (Normandy, France) and the Edwards aquifer (Texas, U.S.A.)

USGS Publications Warehouse

Mahler, B.J.; Valdes, D.; Musgrove, M.; Massei, N.

2008-01-01

Karst aquifers display a range of geologic and geomorphic characteristics in a wide range of climatic and land-use settings; identification of transport dynamics representative of karst aquifers in general could help advance our understanding of these complex systems. To this end, nutrient, turbidity, and major ion dynamics in response to storms were compared at multiple sites in two karst aquifers with contrasting characteristics and settings: the Chalk aquifer (Eure Department, Normandy, France) and the Barton Springs segment of the Edwards Aquifer (Texas, U.S.A.). The Chalk aquifer is typified by high matrix porosity, thick surficial deposits (up to 30??m thick), and agricultural land use; the Barton Springs segment is typified by low matrix porosity, outcropping limestone, and urban land use. Following one to three storms, from 5 to 16 samples from springs and wells were analyzed for major ions, and specific conductance and turbidity were monitored continuously. Comparison of the chemographs indicated some generalized responses, including an increase in turbidity and potassium concentrations and a decrease in major ion and nitrate concentrations with infiltrating storm runoff. Factor analysis of major ions and turbidity revealed strikingly similar behavior of the chemical variables for the two aquifers: The first two factors, explaining more than 75% of the variability, illustrate that dynamics of most major ions (including nitrate) are opposed to those of turbidity and of potassium. The results demonstrate that potassium and nitrate are effective tracers of infiltrating storm runoff and resident ground water, respectively, and the similar results for these two highly contrasting aquifers suggest that the dynamics identified might be applicable to karst systems in general. ?? 2008 Elsevier B.V. All rights reserved.

Nutrient dynamics as indicators of karst processes: comparison of the Chalk aquifer (Normandy, France) and the Edwards aquifer (Texas, U.S.A.).

PubMed

Mahler, B J; Valdes, D; Musgrove, M; Massei, N

2008-05-26

Karst aquifers display a range of geologic and geomorphic characteristics in a wide range of climatic and land-use settings; identification of transport dynamics representative of karst aquifers in general could help advance our understanding of these complex systems. To this end, nutrient, turbidity, and major ion dynamics in response to storms were compared at multiple sites in two karst aquifers with contrasting characteristics and settings: the Chalk aquifer (Eure Department, Normandy, France) and the Barton Springs segment of the Edwards Aquifer (Texas, U.S.A.). The Chalk aquifer is typified by high matrix porosity, thick surficial deposits (up to 30 m thick), and agricultural land use; the Barton Springs segment is typified by low matrix porosity, outcropping limestone, and urban land use. Following one to three storms, from 5 to 16 samples from springs and wells were analyzed for major ions, and specific conductance and turbidity were monitored continuously. Comparison of the chemographs indicated some generalized responses, including an increase in turbidity and potassium concentrations and a decrease in major ion and nitrate concentrations with infiltrating storm runoff. Factor analysis of major ions and turbidity revealed strikingly similar behavior of the chemical variables for the two aquifers: The first two factors, explaining more than 75% of the variability, illustrate that dynamics of most major ions (including nitrate) are opposed to those of turbidity and of potassium. The results demonstrate that potassium and nitrate are effective tracers of infiltrating storm runoff and resident ground water, respectively, and the similar results for these two highly contrasting aquifers suggest that the dynamics identified might be applicable to karst systems in general.

The impact of ultra-low amounts of amino-modified MMT on dynamics and properties of densely cross-linked cyanate ester resins

NASA Astrophysics Data System (ADS)

Bershtein, Vladimir; Fainleib, Alexander; Egorova, Larisa; Gusakova, Kristina; Grigoryeva, Olga; Kirilenko, Demid; Konnikov, Semen; Ryzhov, Valery; Yakushev, Pavel; Lavrenyuk, Natalia

2015-04-01

Thermostable nanocomposites based on densely cross-linked cyanate ester resins (CER), derived from bisphenol E and doped by 0.01 to 5 wt. % amino-functionalized 2D montmorillonite (MMT) nanoparticles, were synthesized and characterized using Fourier transform infrared (FTIR), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), wide-angle X-ray diffraction (WAXD), dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), far-infrared (Far-IR), and creep rate spectroscopy (CRS) techniques. It was revealed that ultra-low additives, e.g., 0.025 to 0.1 wt. %, of amino-MMT nanolayers covalently embedded into CER network exerted an anomalously large impact on its dynamics and properties resulting, in particular, in some suppression of dynamics, increasing the onset of glass transition temperature by 30° to 40° and twofold rise of modulus in temperature range from 20°C to 200°C. Contrarily, the effects became negligibly small or even negative at increased amino-MMT contents, especially at 2 and 5 wt. %. That could be explained by TEM/EDXS data displaying predominance of individual amino-MMT nanolayers and their thin (2 to 3 nanolayers) stacks over more thick tactoids (5 to 10 nanolayers) and the large amino-MMT aggregates (100 to 500 nm in thickness) reversing the composite structure produced with increasing of amino-MMT content within CER matrix. The revealed effect of ultra-low amino-MMT content testifies in favor of the idea about the extraordinarily enhanced long-range action of the `constrained dynamics' effect in the case of densely cross-linked polymer networks.

Study of time-lapse processing for dynamic hydrologic conditions. [electronic satellite image analysis console for Earth Resources Technology Satellites imagery

NASA Technical Reports Server (NTRS)

Serebreny, S. M.; Evans, W. E.; Wiegman, E. J.

1974-01-01

The usefulness of dynamic display techniques in exploiting the repetitive nature of ERTS imagery was investigated. A specially designed Electronic Satellite Image Analysis Console (ESIAC) was developed and employed to process data for seven ERTS principal investigators studying dynamic hydrological conditions for diverse applications. These applications include measurement of snowfield extent and sediment plumes from estuary discharge, Playa Lake inventory, and monitoring of phreatophyte and other vegetation changes. The ESIAC provides facilities for storing registered image sequences in a magnetic video disc memory for subsequent recall, enhancement, and animated display in monochrome or color. The most unique feature of the system is the capability to time lapse the imagery and analytic displays of the imagery. Data products included quantitative measurements of distances and areas, binary thematic maps based on monospectral or multispectral decisions, radiance profiles, and movie loops. Applications of animation for uses other than creating time-lapse sequences are identified. Input to the ESIAC can be either digital or via photographic transparencies.

Global Low Frequency Protein Motions in Long-Range Allosteric Signaling

NASA Astrophysics Data System (ADS)

McLeish, Tom; Rogers, Thomas; Townsend, Philip; Burnell, David; Pohl, Ehmke; Wilson, Mark; Cann, Martin; Richards, Shane; Jones, Matthew

2015-03-01

We present a foundational theory for how allostery can occur as a function of low frequency dynamics without a change in protein structure. Elastic inhomogeneities allow entropic ``signalling at a distance.'' Remarkably, many globular proteins display just this class of elastic structure, in particular those that support allosteric binding of substrates (long-range co-operative effects between the binding sites of small molecules). Through multi-scale modelling of global normal modes we demonstrate negative co-operativity between the two cAMP ligands without change to the mean structure. Crucially, the value of the co-operativity is itself controlled by the interactions around a set of third allosteric ``control sites.'' The theory makes key experimental predictions, validated by analysis of variant proteins by a combination of structural biology and isothermal calorimetry. A quantitative description of allostery as a free energy landscape revealed a protein ``design space'' that identified the key inter- and intramolecular regulatory parameters that frame CRP/FNR family allostery. Furthermore, by analyzing naturally occurring CAP variants from diverse species, we demonstrate an evolutionary selection pressure to conserve residues crucial for allosteric control. The methodology establishes the means to engineer allosteric mechanisms that are driven by low frequency dynamics.

Is there a preference for linearity when viewing natural images?

NASA Astrophysics Data System (ADS)

Kane, David; Bertamío, Marcelo

2015-01-01

The system gamma of the imaging pipeline, defined as the product of the encoding and decoding gammas, is typically greater than one and is stronger for images viewed with a dark background (e.g. cinema) than those viewed in lighter conditions (e.g. office displays).1-3 However, for high dynamic range (HDR) images reproduced on a low dynamic range (LDR) monitor, subjects often prefer a system gamma of less than one,4 presumably reflecting the greater need for histogram equalization in HDR images. In this study we ask subjects to rate the perceived quality of images presented on a LDR monitor using various levels of system gamma. We reveal that the optimal system gamma is below one for images with a HDR and approaches or exceeds one for images with a LDR. Additionally, the highest quality scores occur for images where a system gamma of one is optimal, suggesting a preference for linearity (where possible). We find that subjective image quality scores can be predicted by computing the degree of histogram equalization of the lightness distribution. Accordingly, an optimal, image dependent system gamma can be computed that maximizes perceived image quality.

Prediction-guided quantization for video tone mapping

NASA Astrophysics Data System (ADS)

Le Dauphin, Agnès.; Boitard, Ronan; Thoreau, Dominique; Olivier, Yannick; Francois, Edouard; LeLéannec, Fabrice

2014-09-01

Tone Mapping Operators (TMOs) compress High Dynamic Range (HDR) content to address Low Dynamic Range (LDR) displays. However, before reaching the end-user, this tone mapped content is usually compressed for broadcasting or storage purposes. Any TMO includes a quantization step to convert floating point values to integer ones. In this work, we propose to adapt this quantization, in the loop of an encoder, to reduce the entropy of the tone mapped video content. Our technique provides an appropriate quantization for each mode of both the Intra and Inter-prediction that is performed in the loop of a block-based encoder. The mode that minimizes a rate-distortion criterion uses its associated quantization to provide integer values for the rest of the encoding process. The method has been implemented in HEVC and was tested over two different scenarios: the compression of tone mapped LDR video content (using the HM10.0) and the compression of perceptually encoded HDR content (HM14.0). Results show an average bit-rate reduction under the same PSNR for all the sequences and TMO considered of 20.3% and 27.3% for tone mapped content and 2.4% and 2.7% for HDR content.

Investigation of Oxygen Diffusion in Irradiated UO2 with MD Simulation

NASA Astrophysics Data System (ADS)

Günay, Seçkin D.

2016-11-01

In this study, irradiated UO2 is analyzed by atomistic simulation method to obtain diffusion coefficient of oxygen ions. For this purpose, a couple of molecular dynamics (MD) supercells containing Frenkel, Schottky, vacancy and interstitial types for both anion and cation defects is constructed individually. Each of their contribution is used to calculate the total oxygen diffusion for both intrinsic and extrinsic ranges. The results display that irradiation-induced defects contribute the most to the overall oxygen diffusion at temperatures below 800-1,200 K. This result is quite sensible because experimental data shows that, from room temperature to about 1,500 K, irradiation-induced swelling decreases and irradiated UO2 lattice parameter is gradually recovered because defects annihilate each other. Another point is that, concentration of defects enhances the irradiation-induced oxygen diffusion. Irradiation type also has the similar effect, namely oxygen diffusion in crystals irradiated with α-particles is more than the crystals irradiated with neutrons. Dynamic Frenkel defects dominate the oxygen diffusion data above 1,500—1,800 K. In all these temperature ranges, thermally induced Frenkel defects make no significant contribution to overall oxygen diffusion.

Cooperation dynamics of generalized reciprocity in state-based social dilemmas

NASA Astrophysics Data System (ADS)

Stojkoski, Viktor; Utkovski, Zoran; Basnarkov, Lasko; Kocarev, Ljupco

2018-05-01

We introduce a framework for studying social dilemmas in networked societies where individuals follow a simple state-based behavioral mechanism based on generalized reciprocity, which is rooted in the principle "help anyone if helped by someone." Within this general framework, which applies to a wide range of social dilemmas including, among others, public goods, donation, and snowdrift games, we study the cooperation dynamics on a variety of complex network examples. By interpreting the studied model through the lenses of nonlinear dynamical systems, we show that cooperation through generalized reciprocity always emerges as the unique attractor in which the overall level of cooperation is maximized, while simultaneously exploitation of the participating individuals is prevented. The analysis elucidates the role of the network structure, here captured by a local centrality measure which uniquely quantifies the propensity of the network structure to cooperation by dictating the degree of cooperation displayed both at the microscopic and macroscopic level. We demonstrate the applicability of the analysis on a practical example by considering an interaction structure that couples a donation process with a public goods game.

Quantum correlation dynamics in photosynthetic processes assisted by molecular vibrations

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

Giorgi, G.L., E-mail: g.giorgi@inrim.it; Roncaglia, M.; Raffa, F.A.

2015-10-15

During the long course of evolution, nature has learnt how to exploit quantum effects. In fact, recent experiments reveal the existence of quantum processes whose coherence extends over unexpectedly long time and space ranges. In particular, photosynthetic processes in light-harvesting complexes display a typical oscillatory dynamics ascribed to quantum coherence. Here, we consider the simple model where a dimer made of two chromophores is strongly coupled with a quasi-resonant vibrational mode. We observe the occurrence of wide oscillations of genuine quantum correlations, between electronic excitations and the environment, represented by vibrational bosonic modes. Such a quantum dynamics has been unveiledmore » through the calculation of the negativity of entanglement and the discord, indicators widely used in quantum information for quantifying the resources needed to realize quantum technologies. We also discuss the possibility of approximating additional weakly-coupled off-resonant vibrational modes, simulating the disturbances induced by the rest of the environment, by a single vibrational mode. Within this approximation, one can show that the off-resonant bath behaves like a classical source of noise.« less

Displaying Data As Movies

NASA Technical Reports Server (NTRS)

Moore, Judith G.

1992-01-01

NMSB Movie computer program displays large sets of data (more than million individual values). Presentation dynamic, rapidly displaying sequential image "frames" in main "movie" window. Any sequence of two-dimensional sets of data scaled between 0 and 255 (1-byte resolution) displayed as movie. Time- or slice-wise progression of data illustrated. Originally written to present data from three-dimensional ultrasonic scans of damaged aerospace composite materials, illustrates data acquired by thermal-analysis systems measuring rates of heating and cooling of various materials. Developed on Macintosh IIx computer with 8-bit color display adapter and 8 megabytes of memory using Symantec Corporation's Think C, version 4.0.

Range expansion promotes cooperation in an experimental microbial metapopulation

PubMed Central

Datta, Manoshi Sen; Korolev, Kirill S.; Cvijovic, Ivana; Dudley, Carmel; Gore, Jeff

2013-01-01

Natural populations throughout the tree of life undergo range expansions in response to changes in the environment. Recent theoretical work suggests that range expansions can have a strong effect on evolution, even leading to the fixation of deleterious alleles that would normally be outcompeted in the absence of migration. However, little is known about how range expansions might influence alleles under frequency- or density-dependent selection. Moreover, there is very little experimental evidence to complement existing theory, since expanding populations are difficult to study in the natural environment. In this study, we have used a yeast experimental system to explore the effect of range expansions on the maintenance of cooperative behaviors, which commonly display frequency- and density-dependent selection and are widespread in nature. We found that range expansions favor the maintenance of cooperation in two ways: (i) through the enrichment of cooperators at the front of the expanding population and (ii) by allowing cooperators to “outrun” an invading wave of defectors. In this system, cooperation is enhanced through the coupling of population ecology and evolutionary dynamics in expanding populations, thus providing experimental evidence for a unique mechanism through which cooperative behaviors could be maintained in nature. PMID:23569263

Attention and apparent motion.

PubMed

Horowitz, T; Treisman, A

1994-01-01

Two dissociations between short- and long-range motion in visual search are reported. Previous research has shown parallel processing for short-range motion and apparently serial processing for long-range motion. This finding has been replicated and it has also been found that search for short-range targets can be impaired both by using bicontrast stimuli, and by prior adaptation to the target direction of motion. Neither factor impaired search in long-range motion displays. Adaptation actually facilitated search with long-range displays, which is attributed to response-level effects. A feature-integration account of apparent motion is proposed. In this theory, short-range motion depends on specialized motion feature detectors operating in parallel across the display, but subject to selective adaptation, whereas attention is needed to link successive elements when they appear at greater separations, or across opposite contrasts.

Moving base simulation of an ASTOVL lift-fan aircraft

NASA Technical Reports Server (NTRS)

Chung, William W. Y.; Borchers, Paul F.; Franklin, James A.

1995-01-01

Using a generalized simulation model, a moving-base simulation of a lift-fan short takeoff/vertical landing fighter aircraft was conducted on the Vertical Motion Simulator at Ames Research Center. Objectives of the experiment were to (1) assess the effects of lift-fan propulsion system design features on aircraft control during transition and vertical flight including integration of lift fan/lift/cruise engine/aerodynamic controls and lift fan/lift/cruise engine dynamic response, (2) evaluate pilot-vehicle interface with the control system and head-up display including control modes for low-speed operational tasks and control mode/display integration, and (3) conduct operational evaluations of this configuration during takeoff, transition, and landing similar to those carried out previously by the Ames team for the mixed-flow, vectored thrust, and augmentor-ejector concepts. Based on results of the simulation, preliminary assessments of acceptable and borderline lift-fan and lift/cruise engine thrust response characteristics were obtained. Maximum pitch, roll, and yaw control power used during transition, hover, and vertical landing were documented. Control and display mode options were assessed for their compatibility with a range of land-based and shipboard operations from takeoff to cruise through transition back to hover and vertical landing. Flying qualities were established for candidate control modes and displays for instrument approaches and vertical landings aboard an LPH assault ship and DD-963 destroyer. Test pilot and engineer teams from the Naval Air Warfare Center, Boeing, Lockheed, McDonnell Douglas, and the British Defence Research Agency participated in the program.

[A novel protein equalizer based on single chain variable fragment display M13 phage library for nephropathy patient urine study].

PubMed

Zhao, Peng; Tao, Dingyin; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2009-05-01

A novel protein equalizer was developed with single chain variable fragment (scFv) library displaying M13 phage covalently bonded on monolithic cryogel. Due to the great number and various kinds of displayed scFv fragments, as well as strong and specific binding capacity between scFv fragments and proteins, a new protein equalizer technology is preferable in the pretreatment of complex protein samples. After the sample dissolved in phosphate buffer solution (PBS), it was repeatedly loaded onto the equalizer for five times, the bound proteins were in sequence eluted by 2 mol/L NaCl and 50 mmol/L Gly-HC1 (pH 2.5) solution, followed by digestion with thrombin. All proteins or peptides collected from each fraction were further analyzed by high performance liquid chromatography-electrospray tandem mass spectrometry (RPLC-ESI-MS/MS) with a serially coupled long microcolumn. Compared with the untreated samples, the identified protein number was increased from 142 to 396. Furthermore, from sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis results, it was found that the protein concentration difference was reduced obviously in the eluant of direct sample loading, and most high abundance proteins were identified in the eluant of NaCl. All these results demonstrate that the novel protein equalizer with scFv display M13 phage library immobilized on cyrogel could effectively reduce the dynamic range of proteins in complex samples, enabling the identification of more low abundance proteins.

Single-image hard-copy display of the spine utilizing digital radiography

NASA Astrophysics Data System (ADS)

Artz, Dorothy S.; Janchar, Timothy; Milzman, David; Freedman, Matthew T.; Mun, Seong K.

1997-04-01

Regions of the entire spine contain a wide latitude of tissue densities within the imaged field of view presenting a problem for adequate radiological evaluation. With screen/film technology, the optimal technique for one area of the radiograph is sub-optimal for another area. Computed radiography (CR) with its inherent wide dynamic range, has been shown to be better than screen/film for lateral cervical spine imaging, but limitations are still present with standard image processing. By utilizing a dynamic range control (DRC) algorithm based on unsharp masking and signal transformation prior to gradation and frequency processing within the CR system, more vertebral bodies can be seen on a single hard copy display of the lateral cervical, thoracic, and thoracolumbar examinations. Examinations of the trauma cross-table lateral cervical spine, lateral thoracic spine, and lateral thoracolumbar spine were collected on live patient using photostimulable storage phosphor plates, the Fuji FCR 9000 reader, and the Fuji AC-3 computed radiography reader. Two images were produced from a single exposure; one with standard image processing and the second image with the standard process and the additional DRC algorithm. Both sets were printed from a Fuji LP 414 laser printer. Two different DRC algorithms were applied depending on which portion of the spine was not well visualized. One algorithm increased optical density and the second algorithm decreased optical density. The resultant image pairs were then reviewed by a panel of radiologists. Images produced with the additional DRC algorithm demonstrated improved visualization of previously 'under exposed' and 'over exposed' regions within the same image. Where lung field had previously obscured bony detail of the lateral thoracolumbar spine due to 'over exposure,' the image with the DRC applied to decrease the optical density allowed for easy visualization of the entire area of interest. For areas of the lateral cervical spine and lateral thoracic spine that typically have a low optical density value, the DRC algorithm used increased the optical density over that region improving visualization of C7-T2 and T11-L2 vertebral bodies; critical in trauma radiography. Emergency medicine physicians also reviewing the lateral cervical spine images were able to clear 37% of the DRC images compared to 30% of the non-DRC images for removal of the cervical collar. The DRC processed images reviewed by the physicians do not have a typical screen/film appearance; however, these different images were preferred for the three examinations in this study. This method of image processing after being tested and accepted, is in use clinically at Georgetown University Medical Center Department of Radiology for the following examinations: cervical spine, lateral thoracic spine, lateral thoracolumbar examinations, facial bones, shoulder, sternum, feet and portable chest. Computed radiography imaging of the spine is improved with the addition of histogram equalization known as dynamic range control (DRC). More anatomical structures are visualized on a single hard copy display.

Sequentially allocated clinical trial of rhythmic stabilization exercises and TENS in women with chronic low back pain.

PubMed

Kofotolis, Nikolaos D; Vlachopoulos, Symeon P; Kellis, Eleftherios

2008-02-01

To examine the effectiveness of rhythmic stabilization exercises and transcutaneous electrical nerve stimulation (TENS) and their combination in treating women with chronic low back pain. Sequentially allocated, single-blinded and controlled study, with a two-month follow-up. The data were collected in a patient rehabilitation setting. A total of 92 women (34-46 years old) with chronic low back pain were studied. Sequential allocation was undertaken into four groups: ;rhythmic stabilization' (n=23), ;rhythmic stabilization - TENS' (n=23), TENS (n=23), and a placebo group (n = 23). Each programme lasted for four weeks. All outcome measures were assessed prior to, immediately after, four weeks and eight weeks post intervention. Data were obtained on functional disability, pain intensity, trunk extension range of motion, dynamic endurance of trunk flexion and static endurance of trunk extension. A total of 88 patients provided two-month follow-up data. The ;rhythmic stabilization' and the ;rhythmic stabilization - TENS' groups displayed statistically significant (P<0.05) improvements in functional disability and pain intensity (ranging from 21.2 to 42.8%), trunk extension range of motion (ranging from 6.5 to 25.5%), dynamic endurance of trunk flexion and static endurance of trunk extension (ranging from 13.5 to 74.3%) compared with the remaining groups. The rhythmic stabilization programmes resulted in more gains in women with chronic low back pain regarding the present outcome variables compared with the other groups; therefore, its application in female chronic low back pain patients aged 34-46 years is recommended.

A manual control theory analysis of vertical situation displays for STOL aircraft

NASA Technical Reports Server (NTRS)

Baron, S.; Levison, W. H.

1973-01-01

Pilot-vehicle-display systems theory is applied to the analysis of proposed vertical situation displays for manual control in approach-to-landing of a STOL aircraft. The effects of display variables on pilot workload and on total closed-loop system performance was calculated using an optimal-control model for the human operator. The steep approach of an augmentor wing jet STOL aircraft was analyzed. Both random turbulence and mean-wind shears were considered. Linearized perturbation equations were used to describe longitudinal and lateral dynamics of the aircraft. The basic display configuration was one that abstracted the essential status information (including glide-slope and localizer errors) of an EADI display. Proposed flight director displays for both longitudinal and lateral control were also investigated.

An improved instantaneous frequency meter for use with a multi-trace CRO: re-examination of the principles involved.

PubMed

Obara, S; Nagai, T

1983-01-01

The instantaneous frequency display of single unit discharges provides a useful measure of neuronal activities. Such a device must produce voltage outputs proportional to the reciprocal of each inter-spike interval by on-line computation of the hyperbola of V = a/t. Segment approximation of the required hyperbola can be made by a series of exponential functions which increase in time constants by a factor of m. Numerical analysis of a normalized function indicates possible error maxima of 3.4, 2.4 and 1.1% for m of 2, 1.8 and 1.5, respectively. This prediction is fully confirmed by the actual performance where m of 1.5 is adopted. The test circuit combines only readily available ICs and other components, to give a linear F-V conversion over a dynamic range of 4-600 Hz with error maxima of approximately 1%. The outputs are square pulses of approximately 1.5 ms in duration through the use of a flexible sample-hold circuit. Compared with that of earlier models, this display mode gives better photographic records with the base-line in simultaneous multi-trace display. Simple and systematic methods are described for designing a circuit to one's own specifications, and also for compensating for component variations.

Public Health Effects of Restricting Retail Tobacco Product Displays and Ads

PubMed Central

Levy, David T.; Lindblom, Eric N.; Fleischer, Nancy L.; Thrasher, James; Mohlman, Mary Kate; Zhang, Yian; Monshouwer, Karin; Nagelhout, Gera E.

2015-01-01

Objectives To estimate the public health impact from restricting US retail point-of-sale (POS) tobacco product displays and advertising. Methods Based on existing research, this paper estimates the effects on initiation and cessation rates from restricting POS tobacco product displays and ads in the US and uses the SimSmoke simulation model to project related smoking declines and health benefits. Results New comprehensive POS restrictions are projected to reduce smoking prevalence by approximately 16% [range=3%–31%] relative to the status quo by 2065, preventing about 630,000 smoking-attributable deaths [range=108,000–1,225,000], 215,000 low birth weight births [range=33,000–421,000], 140,000 preterm births [range=22,000–271,000], and 1900 infant deaths from SIDSs [range=300–3800]. Conclusions Federal, state, or local action to restrict POS tobacco product displays and ads would contribute to a substantial reduction in smoking-attributed death and disease. PMID:26191538

Dynamic Calorimetry for Students

ERIC Educational Resources Information Center

Kraftmakher, Yaakov

2007-01-01

A student experiment on dynamic calorimetry is described. Dynamic calorimetry is a powerful technique for calorimetric studies, especially at high temperatures and pressures. A low-power incandescent lamp serves as the sample. The ScienceWorkshop data-acquisition system with DataStudio software from PASCO Scientific displays the results of the…

Measuring emotional and cognitive empathy using dynamic, naturalistic, and spontaneous emotion displays.

PubMed

Buck, Ross; Powers, Stacie R; Hull, Kyle S

2017-10-01

Most measures of nonverbal receiving ability use posed expressions as stimuli. As empathy measures, such stimuli lack ecological validity, as the participant is not actually experiencing emotion. An alternative approach uses natural and dynamic displays of spontaneous expressions. The Communication of Affect Receiving Ability Test (CARAT) uses as stimuli spontaneous facial expressions and gestures filmed by an unobtrusive camera of solitary participants responding to emotional images. This article reports the development and initial validation of the CARAT-Spontaneous, Posed, Regulated (CARAT-SPR), which measures both abilities to detect emotion from spontaneous displays (emotion communication accuracy) and to differentiate spontaneous, posed, and regulated displays (expression categorization ability). Although spontaneous displays are natural responses to emotional images, posed displays involve asking the sender to display "as if" responding to a particular sort of image when no image is in fact present (simulation), while Regulated displays involve asking the sender to display "as if" responding to a particular sort of image when an image of opposite valence is in fact present (masking). Expression categorization ability involves judging deception-simulation and masking-and conceptually involves a kind of perspective-taking or cognitive empathy. Emotion communication using spontaneous clips achieved a high level of accuracy and was strongly correlated with ratings of sender expressivity. Expression categorization ability was not significantly correlated with expressivity ratings and was modestly negatively correlated with emotion communication accuracy. In a brief version of the CARAT-SPR, women showed evidence of greater emotion signal detection, whereas men reported greater confidence in expression categorization. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Fractional-order leaky integrate-and-fire model with long-term memory and power law dynamics.

PubMed

Teka, Wondimu W; Upadhyay, Ranjit Kumar; Mondal, Argha

2017-09-01

Pyramidal neurons produce different spiking patterns to process information, communicate with each other and transform information. These spiking patterns have complex and multiple time scale dynamics that have been described with the fractional-order leaky integrate-and-Fire (FLIF) model. Models with fractional (non-integer) order differentiation that generalize power law dynamics can be used to describe complex temporal voltage dynamics. The main characteristic of FLIF model is that it depends on all past values of the voltage that causes long-term memory. The model produces spikes with high interspike interval variability and displays several spiking properties such as upward spike-frequency adaptation and long spike latency in response to a constant stimulus. We show that the subthreshold voltage and the firing rate of the fractional-order model make transitions from exponential to power law dynamics when the fractional order α decreases from 1 to smaller values. The firing rate displays different types of spike timing adaptation caused by changes on initial values. We also show that the voltage-memory trace and fractional coefficient are the causes of these different types of spiking properties. The voltage-memory trace that represents the long-term memory has a feedback regulatory mechanism and affects spiking activity. The results suggest that fractional-order models might be appropriate for understanding multiple time scale neuronal dynamics. Overall, a neuron with fractional dynamics displays history dependent activities that might be very useful and powerful for effective information processing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dynamic three-dimensional display of common congenital cardiac defects from reconstruction of two-dimensional echocardiographic images.

PubMed

Hsieh, K S; Lin, C C; Liu, W S; Chen, F L

1996-01-01

Two-dimensional echocardiography had long been a standard diagnostic modality for congenital heart disease. Further attempts of three-dimensional reconstruction using two-dimensional echocardiographic images to visualize stereotypic structure of cardiac lesions have been successful only recently. So far only very few studies have been done to display three-dimensional anatomy of the heart through two-dimensional image acquisition because such complex procedures were involved. This study introduced a recently developed image acquisition and processing system for dynamic three-dimensional visualization of various congenital cardiac lesions. From December 1994 to April 1995, 35 cases were selected in the Echo Laboratory here from about 3000 Echo examinations completed. Each image was acquired on-line with specially designed high resolution image grazmber with EKG and respiratory gating technique. Off-line image processing using a window-architectured interactive software package includes construction of 2-D ehcocardiographic pixel to 3-D "voxel" with conversion of orthogonal to rotatory axial system, interpolation, extraction of region of interest, segmentation, shading and, finally, 3D rendering. Three-dimensional anatomy of various congenital cardiac defects was shown, including four cases with ventricular septal defects, two cases with atrial septal defects, and two cases with aortic stenosis. Dynamic reconstruction of a "beating heart" is recorded as vedio tape with video interface. The potential application of 3D display of the reconstruction from 2D echocardiographic images for the diagnosis of various congenital heart defects has been shown. The 3D display was able to improve the diagnostic ability of echocardiography, and clear-cut display of the various congenital cardiac defects and vavular stenosis could be demonstrated. Reinforcement of current techniques will expand future application of 3D display of conventional 2D images.

Spatial constraints of stereopsis in video displays

NASA Technical Reports Server (NTRS)

Schor, Clifton

1989-01-01

Recent development in video technology, such as the liquid crystal displays and shutters, have made it feasible to incorporate stereoscopic depth into the 3-D representations on 2-D displays. However, depth has already been vividly portrayed in video displays without stereopsis using the classical artists' depth cues described by Helmholtz (1866) and the dynamic depth cues described in detail by Ittleson (1952). Successful static depth cues include overlap, size, linear perspective, texture gradients, and shading. Effective dynamic cues include looming (Regan and Beverly, 1979) and motion parallax (Rogers and Graham, 1982). Stereoscopic depth is superior to the monocular distance cues under certain circumstances. It is most useful at portraying depth intervals as small as 5 to 10 arc secs. For this reason it is extremely useful in user-video interactions such as telepresence. Objects can be manipulated in 3-D space, for example, while a person who controls the operations views a virtual image of the manipulated object on a remote 2-D video display. Stereopsis also provides structure and form information in camouflaged surfaces such as tree foliage. Motion parallax also reveals form; however, without other monocular cues such as overlap, motion parallax can yield an ambiguous perception. For example, a turning sphere, portrayed as solid by parallax can appear to rotate either leftward or rightward. However, only one direction of rotation is perceived when stereo-depth is included. If the scene is static, then stereopsis is the principal cue for revealing the camouflaged surface structure. Finally, dynamic stereopsis provides information about the direction of motion in depth (Regan and Beverly, 1979). Clearly there are many spatial constraints, including spatial frequency content, retinal eccentricity, exposure duration, target spacing, and disparity gradient, which - when properly adjusted - can greatly enhance stereodepth in video displays.

Very long transients, irregular firing, and chaotic dynamics in networks of randomly connected inhibitory integrate-and-fire neurons.

PubMed

Zillmer, Rüdiger; Brunel, Nicolas; Hansel, David

2009-03-01

We present results of an extensive numerical study of the dynamics of networks of integrate-and-fire neurons connected randomly through inhibitory interactions. We first consider delayed interactions with infinitely fast rise and decay. Depending on the parameters, the network displays transients which are short or exponentially long in the network size. At the end of these transients, the dynamics settle on a periodic attractor. If the number of connections per neuron is large ( approximately 1000) , this attractor is a cluster state with a short period. In contrast, if the number of connections per neuron is small ( approximately 100) , the attractor has complex dynamics and very long period. During the long transients the neurons fire in a highly irregular manner. They can be viewed as quasistationary states in which, depending on the coupling strength, the pattern of activity is asynchronous or displays population oscillations. In the first case, the average firing rates and the variability of the single-neuron activity are well described by a mean-field theory valid in the thermodynamic limit. Bifurcations of the long transient dynamics from asynchronous to synchronous activity are also well predicted by this theory. The transient dynamics display features reminiscent of stable chaos. In particular, despite being linearly stable, the trajectories of the transient dynamics are destabilized by finite perturbations as small as O(1/N) . We further show that stable chaos is also observed for postsynaptic currents with finite decay time. However, we report in this type of network that chaotic dynamics characterized by positive Lyapunov exponents can also be observed. We show in fact that chaos occurs when the decay time of the synaptic currents is long compared to the synaptic delay, provided that the network is sufficiently large.

Some Processing and Dynamic-Range Issues in Side-Scan Sonar Work

NASA Astrophysics Data System (ADS)

Asper, V. L.; Caruthers, J. W.

2007-05-01

Often side-scan sonar data are collected in such a way that they afford little opportunity to do more than simply display them as images. These images are often limited in dynamic range and stored only in an 8-bit tiff format of numbers representing less than true intensity values. Furthermore, there is little prior knowledge during a survey of the best range in which to set those eight bits. This can result in clipped strong targets and/or the depth of shadows so that the bits that can be recovered from the image are not fully representative of target or bottom backscatter strengths. Several top-of-the-line sonars do have a means of logging high-bit-rate digital data (sometimes only as an option), but only dedicated specialists pay much attention to such data, if they record them at all. Most users of side-scan sonars are interested only in the images. Discussed in this paper are issues related to storing and processing of high-bit-rate digital data to preserve their integrity for future enhanced, after- the-fact use and ability to recover actual backscatter strengths. This papers discusses issues in the use high-bit- rate, digital side-scan sonar data. This work was supported by the Office of Naval Research, Code 321OA, and the Naval Oceanographic Office, Mine Warfare Program.

Holographic three-dimensional telepresence using large-area photorefractive polymer.

PubMed

Blanche, P-A; Bablumian, A; Voorakaranam, R; Christenson, C; Lin, W; Gu, T; Flores, D; Wang, P; Hsieh, W-Y; Kathaperumal, M; Rachwal, B; Siddiqui, O; Thomas, J; Norwood, R A; Yamamoto, M; Peyghambarian, N

2010-11-04

Holography is a technique that is used to display objects or scenes in three dimensions. Such three-dimensional (3D) images, or holograms, can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. The concept of 3D telepresence, a real-time dynamic hologram depicting a scene occurring in a different location, has attracted considerable public interest since it was depicted in the original Star Wars film in 1977. However, the lack of sufficient computational power to produce realistic computer-generated holograms and the absence of large-area and dynamically updatable holographic recording media have prevented realization of the concept. Here we use a holographic stereographic technique and a photorefractive polymer material as the recording medium to demonstrate a holographic display that can refresh images every two seconds. A 50 Hz nanosecond pulsed laser is used to write the holographic pixels. Multicoloured holographic 3D images are produced by using angular multiplexing, and the full parallax display employs spatial multiplexing. 3D telepresence is demonstrated by taking multiple images from one location and transmitting the information via Ethernet to another location where the hologram is printed with the quasi-real-time dynamic 3D display. Further improvements could bring applications in telemedicine, prototyping, advertising, updatable 3D maps and entertainment.

LCoS-SLM technology based on Digital Electro-optics Platform and using in dynamic optics for application development

NASA Astrophysics Data System (ADS)

Tsai, Chun-Wei; Wang, Chen; Lyu, Bo-Han; Chu, Chen-Hsien

2017-08-01

Digital Electro-optics Platform is the main concept of Jasper Display Corp. (JDC) to develop various applications. These applications are based on our X-on-Silicon technologies, for example, X-on-Silicon technologies could be used on Liquid Crystal on Silicon (LCoS), Micro Light-Emitting Diode on Silicon (μLEDoS), Organic Light-Emitting Diode on Silicon (OLEDoS), and Cell on Silicon (CELLoS), etc. LCoS technology is applied to Spatial Light Modulator (SLM), Dynamic Optics, Wavelength Selective Switch (WSS), Holographic Display, Microscopy, Bio-tech, 3D Printing and Adaptive Optics, etc. In addition, μLEDoS technology is applied to Augmented Reality (AR), Head Up Display (HUD), Head-mounted Display (HMD), and Wearable Devices. Liquid Crystal on Silicon - Spatial Light Modulator (LCoSSLM) based on JDC's On-Silicon technology for both amplitude and phase modulation, have an expanding role in several optical areas where light control on a pixel-by-pixel basis is critical for optimum system performance. Combination of the advantage of hardware and software, we can establish a "dynamic optics" for the above applications or more. Moreover, through the software operation, we can control the light more flexible and easily as programmable light processor.

Prediction and measurement of human pilot dynamic characteristics in a manned rotorcraft simulation

NASA Technical Reports Server (NTRS)

Hess, Ronald A.; Reedy, James T.

1988-01-01

An analytical and experimental study of the human pilot control strategies in a manned rotorcraft simulation is described. The task simulated involves a low-speed, constant-altitude maneuvering task in which a head-down display is utilized to allow the pilot to track a moving hover point. The efficacy of the display law driving an acceleration symbol is determined and the manner in which the prediction and measurement of pilot/vehicle dynamics can be made part of man/machine system evaluations is demonstrated.

A Cockpit Display Designed to Enable Limited Flight Deck Separation Responsibility

NASA Technical Reports Server (NTRS)

Johnson, Walter W.; Battiste, Vernol; Bochow, Sheila Holland

2003-01-01

Cockpit displays need to be substantially improved to serve the goals of situational awareness, conflict detection, and path replanning, in Free Flight. This paper describes the design of such an advanced cockpit display, along with an initial simulation based usability evaluation. Flight crews were particularly enthusiastic about color coding for relative altitude, dynamically pulsing predictors, and the use of 3-D flight plans for alerting and situational awareness.

A Multisite Survey Study of EMR Review Habits, Information Needs, and Display Preferences among Medical ICU Clinicians Evaluating New Patients.

PubMed

Nolan, Matthew E; Cartin-Ceba, Rodrigo; Moreno-Franco, Pablo; Pickering, Brian; Herasevich, Vitaly

2017-10-01

The electronic chart review habits of intensive care unit (ICU) clinicians admitting new patients are largely unknown but necessary to inform the design of existing and future critical care information systems. We conducted a survey study to assess the electronic chart review practices, information needs, workflow, and data display preferences among medical ICU clinicians admitting new patients. We surveyed rotating residents, critical care fellows, advanced practice providers, and attending physicians at three Mayo Clinic sites (Minnesota, Florida, and Arizona) via email with a single follow-up reminder message. Of 234 clinicians invited, 156 completed the full survey (67% response rate). Ninety-two percent of medical ICU clinicians performed electronic chart review for the majority of new patients. Clinicians estimated spending a median (interquartile range (IQR)) of 15 (10-20) minutes for a typical case, and 25 (15-40) minutes for complex cases, with no difference across training levels. Chart review spans 3 or more years for two-thirds of clinicians, with the most relevant categories being imaging, laboratory studies, diagnostic studies, microbiology reports, and clinical notes, although most time is spent reviewing notes. Most clinicians (77%) worry about overlooking important information due to the volume of data (74%) and inadequate display/organization (63%). Potential solutions are chronologic ordering of disparate data types, color coding, and explicit data filtering techniques. The ability to dynamically customize information display for different users and varying clinical scenarios is paramount. Electronic chart review of historical data is an important, prevalent, and potentially time-consuming activity among medical ICU clinicians who would benefit from improved information display systems. Schattauer GmbH Stuttgart.

Computational fluid dynamics vs. inverse dynamics methods to determine passive drag in two breaststroke glide positions.

PubMed

Costa, L; Mantha, V R; Silva, A J; Fernandes, R J; Marinho, D A; Vilas-Boas, J P; Machado, L; Rouboa, A

2015-07-16

Computational fluid dynamics (CFD) plays an important role to quantify, understand and "observe" the water movements around the human body and its effects on drag (D). We aimed to investigate the flow effects around the swimmer and to compare the drag and drag coefficient (CD) values obtained from experiments (using cable velocimetry in a swimming pool) with those of CFD simulations for the two ventral gliding positions assumed during the breaststroke underwater cycle (with shoulders flexed and upper limbs extended above the head-GP1; with shoulders in neutral position and upper limbs extended along the trunk-GP2). Six well-trained breaststroke male swimmers (with reasonable homogeneity of body characteristics) participated in the experimental tests; afterwards a 3D swimmer model was created to fit within the limits of the sample body size profile. The standard k-ε turbulent model was used to simulate the fluid flow around the swimmer model. Velocity ranged from 1.30 to 1.70 m/s for GP1 and 1.10 to 1.50 m/s for GP2. Values found for GP1 and GP2 were lower for CFD than experimental ones. Nevertheless, both CFD and experimental drag/drag coefficient values displayed a tendency to jointly increase/decrease with velocity, except for GP2 CD where CFD and experimental values display opposite tendencies. Results suggest that CFD values obtained by single model approaches should be considered with caution due to small body shape and dimension differences to real swimmers. For better accuracy of CFD studies, realistic individual 3D models of swimmers are required, and specific kinematics respected. Copyright © 2015 Elsevier Ltd. All rights reserved.

Assessment and refinement of real-time travel time algorithms for use in practice : final report, October 2008.

DOT National Transportation Integrated Search

2008-10-01

The FHWA has strongly encouraged transportation departments to display travel times on their Dynamic Message Signs (DMS). The Oregon : Department of Transportation (ODOT) currently displays travel time estimates on three DMSs in the Portland metropol...

Introducing Computational Fluid Dynamics Simulation into Olfactory Display

NASA Astrophysics Data System (ADS)

Ishida, Hiroshi; Yoshida, Hitoshi; Nakamoto, Takamichi

An olfactory display is a device that delivers various odors to the user's nose. It can be used to add special effects to movies and games by releasing odors relevant to the scenes shown on the screen. In order to provide high-presence olfactory stimuli to the users, the display must be able to generate realistic odors with appropriate concentrations in a timely manner together with visual and audio playbacks. In this paper, we propose to use computational fluid dynamics (CFD) simulations in conjunction with the olfactory display. Odor molecules released from their source are transported mainly by turbulent flow, and their behavior can be extremely complicated even in a simple indoor environment. In the proposed system, a CFD solver is employed to calculate the airflow field and the odor dispersal in the given environment. An odor blender is used to generate the odor with the concentration determined based on the calculated odor distribution. Experimental results on presenting odor stimuli synchronously with movie clips show the effectiveness of the proposed system.

Characterization, Modeling, and Failure Analysis of Composite Structure Materials under Static and Dynamic Loading

NASA Astrophysics Data System (ADS)

Werner, Brian Thomas

Composite structures have long been used in many industries where it is advantageous to reduce weight while maintaining high stiffness and strength. Composites can now be found in an ever broadening range of applications: sporting equipment, automobiles, marine and aerospace structures, and energy production. These structures are typically sandwich panels composed of fiber reinforced polymer composite (FRPC) facesheets which provide the stiffness and the strength and a low density polymeric foam core that adds bending rigidity with little additional weight. The expanding use of composite structures exposes them to high energy, high velocity dynamic loadings which produce multi-axial dynamic states of stress. This circumstance can present quite a challenge to designers, as composite structures are highly anisotropic and display properties that are sensitive to loading rates. Computer codes are continually in development to assist designers in the creation of safe, efficient structures. While the design of an optimal composite structure is more complex, engineers can take advantage of the effect of enhanced energy dissipation displayed by a composite when loaded at high strain rates. In order to build and verify effective computer codes, the underlying assumptions must be verified by laboratory experiments. Many of these codes look to use a micromechanical approach to determine the response of the structure. For this, the material properties of the constituent materials must be verified, three-dimensional constitutive laws must be developed, and failure of these materials must be investigated under static and dynamic loading conditions. In this study, simple models are sought not only to ease their implementation into such codes, but to allow for efficient characterization of new materials that may be developed. Characterization of composite materials and sandwich structures is a costly, time intensive process. A constituent based design approach evaluates potential combinations of materials in a much faster and more efficient manner.

Control and Synchronization of Heteroclinic Chaos: Implications for Neurodynamics

NASA Astrophysics Data System (ADS)

Arecchi, F. Tito

2004-12-01

Heteroclinic chaos (HC) implies the recurrent return of the dynamical trajectory to a saddle focus (SF) in whose neighborhood the system response to an external perturbation is very high and hence it is very easy to lock to an external stimulus. Thus HC appears as the easiest way to encode information in time by a train of equal spikes occurring at erratic times. Implementing such a dynamics with a single mode CO2 laser with feedback, we have a heteroclinic connection between the SF and a saddle node (SN) whose role it to regularize the phase space orbit away from SF. Due to these two different fixed points, the laser intensity displays identical spikes separated by erratic ISIs (interspike intervals). Such a dynamics is highly prone to spike-synchronization, either by an external signal or by mutual interaction in a network of identical systems. Applications to communication and noise induced synchronization will be reported. In experimental neuroscience a recent finding is that feature binding ,that is, combination of external stimuli with internal memories into new coherent patterns of meaning, implies the mutual synchronization of axonal spike trains in neurons which can be far away and yet share the same sequence. Several dynamical systems have been proposed to model such a behavior. We introduce a measurable parameter, namely, the synchronization "propensity". Propensity is the amount of synchronization achieved in a chaotic system by a small sinusoidal perturbation of a control parameter. It is very low for coupled Lorenz or FitzHugh-Nagumo chains. It displays isolated peaks for the Hindmarsh-Rose model, showing that this is a convenient description of the bursting behavior typical of neurons in the CPG (central pattern generator) system. Instead, HC shows a high propensity over a wide input frequency range, demonstrating that it is the most convenient model for semantic neurons.

Spatio-temporal correlations in the Manna model in one, three and five dimensions

NASA Astrophysics Data System (ADS)

Willis, Gary; Pruessner, Gunnar

2018-02-01

Although the paradigm of criticality is centered around spatial correlations and their anomalous scaling, not many studies of self-organized criticality (SOC) focus on spatial correlations. Often, integrated observables, such as avalanche size and duration, are used, not least as to avoid complications due to the unavoidable lack of translational invariance. The present work is a survey of spatio-temporal correlation functions in the Manna Model of SOC, measured numerically in detail in d = 1,3 and 5 dimensions and compared to theoretical results, in particular relating them to “integrated” observables such as avalanche size and duration scaling, that measure them indirectly. Contrary to the notion held by some of SOC models organizing into a critical state by re-arranging their spatial structure avalanche by avalanche, which may be expected to result in large, nontrivial, system-spanning spatial correlations in the quiescent state (between avalanches), correlations of inactive particles in the quiescent state have a small amplitude that does not and cannot increase with the system size, although they display (noisy) power law scaling over a range linear in the system size. Self-organization, however, does take place as the (one-point) density of inactive particles organizes into a particular profile that is asymptotically independent of the driving location, also demonstrated analytically in one dimension. Activity and its correlations, on the other hand, display nontrivial long-ranged spatio-temporal scaling with exponents that can be related to established results, in particular avalanche size and duration exponents. The correlation length and amplitude are set by the system size (confirmed analytically for some observables), as expected in systems displaying finite size scaling. In one dimension, we find some surprising inconsistencies of the dynamical exponent. A (spatially extended) mean field theory (MFT) is recovered, with some corrections, in five dimensions.

Laser development for optimal helicopter obstacle warning system LADAR performance

NASA Astrophysics Data System (ADS)

Yaniv, A.; Krupkin, V.; Abitbol, A.; Stern, J.; Lurie, E.; German, A.; Solomonovich, S.; Lubashitz, B.; Harel, Y.; Engart, S.; Shimoni, Y.; Hezy, S.; Biltz, S.; Kaminetsky, E.; Goldberg, A.; Chocron, J.; Zuntz, N.; Zajdman, A.

2005-04-01

Low lying obstacles present immediate danger to both military and civilian helicopters performing low-altitude flight missions. A LADAR obstacle detection system is the natural solution for enhancing helicopter safety and improving the pilot situation awareness. Elop is currently developing an advanced Surveillance and Warning Obstacle Ranging and Display (SWORD) system for the Israeli Air Force. Several key factors and new concepts have contributed to system optimization. These include an adaptive FOV, data memorization, autonomous obstacle detection and warning algorithms and the use of an agile laser transmitter. In the present work we describe the laser design and performance and discuss some of the experimental results. Our eye-safe laser is characterized by its pulse energy, repetition rate and pulse length agility. By dynamically controlling these parameters, we are able to locally optimize the system"s obstacle detection range and scan density in accordance with the helicopter instantaneous maneuver.

Emergence of Alpha and Gamma Like Rhythms in a Large Scale Simulation of Interacting Neurons

NASA Astrophysics Data System (ADS)

Gaebler, Philipp; Miller, Bruce

2007-10-01

In the normal brain, at first glance the electrical activity appears very random. However, certain frequencies emerge during specific stages of sleep or between quiet wake states. This raises the question of whether current mathematical and computational models of interacting neurons can display similar behavior. A recent model developed by Eugene Izhikevich appears to succeed. However, early dynamical simulations used to detect these patterns were possibly compromised by an over-simplified initial condition and evolution algorithm. Utilizing the same model, but a more robust algorithm, here we present our initial results, showing that these patterns persist under a wide range of initial conditions. We employ spectral analysis of the firing patterns of a system of interacting excitatory and inhibitory neurons to demonstrate a bimodal spectrum centered on two frequencies in the range characteristic of alpha and gamma rhythms in the human brain.

Metastability at the Yield-Stress Transition in Soft Glasses

NASA Astrophysics Data System (ADS)

Lulli, Matteo; Benzi, Roberto; Sbragaglia, Mauro

2018-04-01

We study the solid-to-liquid transition in a two-dimensional fully periodic soft-glassy model with an imposed spatially heterogeneous stress. The model we consider consists of droplets of a dispersed phase jammed together in a continuous phase. When the peak value of the stress gets close to the yield stress of the material, we find that the whole system intermittently tunnels to a metastable "fluidized" state, which relaxes back to a metastable "solid" state by means of an elastic-wave dissipation. This macroscopic scenario is studied through the microscopic displacement field of the droplets, whose time statistics displays a remarkable bimodality. Metastability is rooted in the existence, in a given stress range, of two distinct stable rheological branches, as well as long-range correlations (e.g., large dynamic heterogeneity) developed in the system. Finally, we show that a similar behavior holds for a pressure-driven flow, thus suggesting possible experimental tests.

Experimental and numerical investigations of microwave return loss of aircraft inlets with low-pressure plasma

NASA Astrophysics Data System (ADS)

Zhang, Yachun; He, Xiang; Chen, Jianping; Chen, Hongqing; Chen, Li; Zhang, Hongchao; Ni, Xiaowu; Lu, Jian; Shen, Zhonghua

2018-03-01

The relationships between return losses of the cylindrical inlet and plasma discharge parameters are investigated experimentally and numerically. The return losses are measured using a high dynamic range measurement system and simulated by COMSOL Multiphysics when the frequency band of the microwaves is in the range 1-4 GHz. The profiles of the plasma density are estimated using Epstein and Bessel functions. Results show that the incident microwaves can be absorbed by plasma efficaciously. The maximal return loss can reach -13.84 dB when the microwave frequency is 2.3 GHz. The increase of applied power implies augmentation of the return loss, which behaves conversely for gas pressure. The experimental and numerical results display reasonable agreement on return loss, suggesting that the use of plasma is effective in the radar cross section reduction of aircraft inlets.

Three-dimensional displays for natural hazards analysis, using classified Landsat Thematic Mapper digital data and large-scale digital elevation models

NASA Technical Reports Server (NTRS)

Butler, David R.; Walsh, Stephen J.; Brown, Daniel G.

1991-01-01

Methods are described for using Landsat Thematic Mapper digital data and digital elevation models for the display of natural hazard sites in a mountainous region of northwestern Montana, USA. Hazard zones can be easily identified on the three-dimensional images. Proximity of facilities such as highways and building locations to hazard sites can also be easily displayed. A temporal sequence of Landsat TM (or similar) satellite data sets could also be used to display landscape changes associated with dynamic natural hazard processes.

A study of payload specialist station monitor size constraints. [space shuttle orbiters

NASA Technical Reports Server (NTRS)

Kirkpatrick, M., III; Shields, N. L., Jr.; Malone, T. B.

1975-01-01

Constraints on the CRT display size for the shuttle orbiter cabin are studied. The viewing requirements placed on these monitors were assumed to involve display of imaged scenes providing visual feedback during payload operations and display of alphanumeric characters. Data on target recognition/resolution, target recognition, and range rate detection by human observers were utilized to determine viewing requirements for imaged scenes. Field-of-view and acuity requirements for a variety of payload operations were obtained along with the necessary detection capability in terms of range-to-target size ratios. The monitor size necessary to meet the acuity requirements was established. An empirical test was conducted to determine required recognition sizes for displayed alphanumeric characters. The results of the test were used to determine the number of characters which could be simultaneously displayed based on the recognition size requirements using the proposed monitor size. A CRT display of 20 x 20 cm is recommended. A portion of the display area is used for displaying imaged scenes and the remaining display area is used for alphanumeric characters pertaining to the displayed scene. The entire display is used for the character alone mode.

Miniaturized LEDs for flat-panel displays

NASA Astrophysics Data System (ADS)

Radauscher, Erich J.; Meitl, Matthew; Prevatte, Carl; Bonafede, Salvatore; Rotzoll, Robert; Gomez, David; Moore, Tanya; Raymond, Brook; Cok, Ronald; Fecioru, Alin; Trindade, António Jose; Fisher, Brent; Goodwin, Scott; Hines, Paul; Melnik, George; Barnhill, Sam; Bower, Christopher A.

2017-02-01

Inorganic light emitting diodes (LEDs) serve as bright pixel-level emitters in displays, from indoor/outdoor video walls with pixel sizes ranging from one to thirty millimeters to micro displays with more than one thousand pixels per inch. Pixel sizes that fall between those ranges, roughly 50 to 500 microns, are some of the most commercially significant ones, including flat panel displays used in smart phones, tablets, and televisions. Flat panel displays that use inorganic LEDs as pixel level emitters (μILED displays) can offer levels of brightness, transparency, and functionality that are difficult to achieve with other flat panel technologies. Cost-effective production of μILED displays requires techniques for precisely arranging sparse arrays of extremely miniaturized devices on a panel substrate, such as transfer printing with an elastomer stamp. Here we present lab-scale demonstrations of transfer printed μILED displays and the processes used to make them. Demonstrations include passive matrix μILED displays that use conventional off-the shelf drive ASICs and active matrix μILED displays that use miniaturized pixel-level control circuits from CMOS wafers. We present a discussion of key considerations in the design and fabrication of highly miniaturized emitters for μILED displays.

Designing and evaluating symbols for electronic displays of navigation information : symbol stereotypes and symbol-feature rules

DOT National Transportation Integrated Search

2005-09-30

There is currently no common symbology standard for the electronic display of navigation information. The wide range of display technology and the different functions these displays support makes it difficult to design symbols that are easily recogni...

Enzyme Sequestration as a Tuning Point in Controlling Response Dynamics of Signalling Networks

PubMed Central

Ollivier, Julien F.; Soyer, Orkun S.

2016-01-01

Signalling networks result from combinatorial interactions among many enzymes and scaffolding proteins. These complex systems generate response dynamics that are often essential for correct decision-making in cells. Uncovering biochemical design principles that underpin such response dynamics is a prerequisite to understand evolved signalling networks and to design synthetic ones. Here, we use in silico evolution to explore the possible biochemical design space for signalling networks displaying ultrasensitive and adaptive response dynamics. By running evolutionary simulations mimicking different biochemical scenarios, we find that enzyme sequestration emerges as a key mechanism for enabling such dynamics. Inspired by these findings, and to test the role of sequestration, we design a generic, minimalist model of a signalling cycle, featuring two enzymes and a single scaffolding protein. We show that this simple system is capable of displaying both ultrasensitive and adaptive response dynamics. Furthermore, we find that tuning the concentration or kinetics of the sequestering protein can shift system dynamics between these two response types. These empirical results suggest that enzyme sequestration through scaffolding proteins is exploited by evolution to generate diverse response dynamics in signalling networks and could provide an engineering point in synthetic biology applications. PMID:27163612

Projection-type see-through holographic three-dimensional display

NASA Astrophysics Data System (ADS)

Wakunami, Koki; Hsieh, Po-Yuan; Oi, Ryutaro; Senoh, Takanori; Sasaki, Hisayuki; Ichihashi, Yasuyuki; Okui, Makoto; Huang, Yi-Pai; Yamamoto, Kenji

2016-10-01

Owing to the limited spatio-temporal resolution of display devices, dynamic holographic three-dimensional displays suffer from a critical trade-off between the display size and the visual angle. Here we show a projection-type holographic three-dimensional display, in which a digitally designed holographic optical element and a digital holographic projection technique are combined to increase both factors at the same time. In the experiment, the enlarged holographic image, which is twice as large as the original display device, projected on the screen of the digitally designed holographic optical element was concentrated at the target observation area so as to increase the visual angle, which is six times as large as that for a general holographic display. Because the display size and the visual angle can be designed independently, the proposed system will accelerate the adoption of holographic three-dimensional displays in industrial applications, such as digital signage, in-car head-up displays, smart-glasses and head-mounted displays.

Fractal landscapes in biological systems: long-range correlations in DNA and interbeat heart intervals

NASA Technical Reports Server (NTRS)

Stanley, H. E.; Buldyrev, S. V.; Goldberger, A. L.; Hausdorff, J. M.; Havlin, S.; Mietus, J.; Sciortino, F.; Simons, M.

1992-01-01

Here we discuss recent advances in applying ideas of fractals and disordered systems to two topics of biological interest, both topics having common the appearance of scale-free phenomena, i.e., correlations that have no characteristic length scale, typically exhibited by physical systems near a critical point and dynamical systems far from equilibrium. (i) DNA nucleotide sequences have traditionally been analyzed using models which incorporate the possibility of short-range nucleotide correlations. We found, instead, a remarkably long-range power law correlation. We found such long-range correlations in intron-containing genes and in non-transcribed regulatory DNA sequences as well as intragenomic DNA, but not in cDNA sequences or intron-less genes. We also found that the myosin heavy chain family gene evolution increases the fractal complexity of the DNA landscapes, consistent with the intron-late hypothesis of gene evolution. (ii) The healthy heartbeat is traditionally thought to be regulated according to the classical principle of homeostasis, whereby physiologic systems operate to reduce variability and achieve an equilibrium-like state. We found, however, that under normal conditions, beat-to-beat fluctuations in heart rate display long-range power law correlations.

Constraints on the properties of Pluto's nitrogen-ice rich layer from convection simulations

NASA Astrophysics Data System (ADS)

Wong, T.; McKinnon, W. B.; Schenk, P.

2016-12-01

Pluto's Sputnik Planum basin (informally named) displays regular cellular patterns strongly suggesting that solid-state convection is occurring in a several-kilometers-deep nitrogen-ice rich layer (McKinnon et al., Convection in a volatile nitrogen-ice-rich layer drives Pluto's geological vigour, Nature 534, 82-85, 2016). We investigate the behavior of thermal convection in 2-D that covers a range of parameters applicable to the nitrogen ice layer to constrain its properties such that these long-wavelength surface features can be explained. We perform a suite of numerical simulations of convection with basal heating and temperature-dependent viscosity in either exponential form or Arrhenius form. For a plausible range of Rayleigh numbers and viscosity contrasts for solid nitrogen, convection can occur in all possible regimes: sluggish lid, transitional, or stagnant lid, or the layer could be purely conducting. We suggest the range of depth and temperature difference across the layer for convection to occur. We observe that the plume dynamics can be widely different in terms of the aspect ratio of convecting cells, or the width and spacing of plumes, and also in the lateral movement of plumes. These differences depend on the regime of convection determined by the Rayleigh number and the actual viscosity contrast across the layer, but is not sensitive to whether the viscosity is in Arrhenius or exponential form. The variations in plume dynamics result in different types of dynamic topography, which can be compared with the observed horizontal and vertical scales of the cells in Sputnik Planum. Based on these simulations we suggest several different possibilities for the formation and evolution of Sputnik Planum, which may be a consequence of the time-dependent behavior of thermal convection.

Post-Traumatic Stress Constrains the Dynamic Repertoire of Neural Activity.

PubMed

Mišić, Bratislav; Dunkley, Benjamin T; Sedge, Paul A; Da Costa, Leodante; Fatima, Zainab; Berman, Marc G; Doesburg, Sam M; McIntosh, Anthony R; Grodecki, Richard; Jetly, Rakesh; Pang, Elizabeth W; Taylor, Margot J

2016-01-13

Post-traumatic stress disorder (PTSD) is an anxiety disorder arising from exposure to a traumatic event. Although primarily defined in terms of behavioral symptoms, the global neurophysiological effects of traumatic stress are increasingly recognized as a critical facet of the human PTSD phenotype. Here we use magnetoencephalographic recordings to investigate two aspects of information processing: inter-regional communication (measured by functional connectivity) and the dynamic range of neural activity (measured in terms of local signal variability). We find that both measures differentiate soldiers diagnosed with PTSD from soldiers without PTSD, from healthy civilians, and from civilians with mild traumatic brain injury, which is commonly comorbid with PTSD. Specifically, soldiers with PTSD display inter-regional hypersynchrony at high frequencies (80-150 Hz), as well as a concomitant decrease in signal variability. The two patterns are spatially correlated and most pronounced in a left temporal subnetwork, including the hippocampus and amygdala. We hypothesize that the observed hypersynchrony may effectively constrain the expression of local dynamics, resulting in less variable activity and a reduced dynamic repertoire. Thus, the re-experiencing phenomena and affective sequelae in combat-related PTSD may result from functional networks becoming "stuck" in configurations reflecting memories, emotions, and thoughts originating from the traumatizing experience. The present study investigates the effects of post-traumatic stress disorder (PTSD) in combat-exposed soldiers. We find that soldiers with PTSD exhibit hypersynchrony in a circuit of temporal lobe areas associated with learning and memory function. This rigid functional architecture is associated with a decrease in signal variability in the same areas, suggesting that the observed hypersynchrony may constrain the expression of local dynamics, resulting in a reduced dynamic range. Our findings suggest that the re-experiencing of traumatic events in PTSD may result from functional networks becoming locked in configurations that reflect memories, emotions, and thoughts associated with the traumatic experience. Copyright © 2016 the authors 0270-6474/16/360419-13$15.00/0.

A screen-printed flexible flow sensor

NASA Astrophysics Data System (ADS)

Moschos, A.; Syrovy, T.; Syrova, L.; Kaltsas, G.

2017-04-01

A thermal flow sensor was printed on a flexible plastic substrate using exclusively screen-printing techniques. The presented device was implemented with custom made screen-printed thermistors, which allows simple, cost-efficient production on a variety of flexible substrates while maintaining the typical advantages of thermal flow sensors. Evaluation was performed for both static (zero flow) and dynamic conditions using a combination of electrical measurements and IR imaging techniques in order to determine important characteristics, such as temperature response, output repeatability, etc. The flow sensor was characterized utilizing the hot-wire and calorimetric principles of operation, while the preliminary results appear to be very promising, since the sensor was successfully evaluated and displayed adequate sensitivity in a relatively wide flow range.

Discussion on Application of Space Materials and Technological Innovation in Dynamic Fashion Show

NASA Astrophysics Data System (ADS)

Huo, Meilin; Kim, Chul Soo; Zhao, Wenhan

2018-03-01

In modern dynamic fashion show, designers often use the latest ideas and technology, and spend their energy in stage effect and overall environment to make audience’s watching a fashion show like an audio-visual feast. With rapid development of China’s science and technology, it has become a design trend to strengthen the relationship between new ideas, new trends and technology in modern art. With emergence of new technology, new methods and new materials, designers for dynamic fashion show stage art can choose the materials with an increasingly large scope. Generation of new technology has also made designers constantly innovate the stage space design means, and made the stage space design innovated constantly on the original basis of experiences. The dynamic clothing display space is on design of clothing display space, layout, platform decoration style, platform models, performing colors, light arrangement, platform background, etc.

Dynamic Patterns in Mood Among Newly Diagnosed Patients With Major Depressive Episode or Panic Disorder and Normal Controls

PubMed Central

Katerndahl, David; Ferrer, Robert; Best, Rick; Wang, Chen-Pin

2007-01-01

Objective: The purpose of this pilot study was to compare the dynamic patterns of hourly mood variation among newly diagnosed primary care patients with major depressive disorder or panic disorder with patterns in patients with neither disorder. Method: Five adult patients with major depressive episode, 5 with panic disorder, and 5 with neither disorder were asked to complete hourly self-assessments of anxiety and depression (using 100-mm visual analog scales) for each hour they were awake during a 30-day period. Time series were analyzed using ARIMA (autoregression, integration, moving average) modeling (to assess periodicity), Lyapunov exponents (to assess sensitivity to initial conditions indicative of chaotic patterns), and correlation dimension saturation (to assess whether an attractor is limiting change). The study was conducted from March to June 2003. Results: Controls displayed circadian rhythms with underlying chaotic variability. Depressed patients did not display circadian rhythm, but did show chaotic dynamics. Panic disorder patients showed circadian rhythms, but 2 of the 4 patients completing the self-assessments displayed nonchaotic underlying patterns. Conclusions: Patients with major depressive disorder or panic disorder may differ from controls and from each other in their patterns of mood variability. There is a need for more research on the dynamics of mood among patients with mental disorders. PMID:17632650

Optimization of electro-optical parameters of LCD for advertising systems

NASA Astrophysics Data System (ADS)

Olifierczuk, Marek; Zielinski, Jerzy; Klosowicz, Stanislaw J.

1998-02-01

The analysis of the optimization of negative image twisted nematic LCD is presented. Theoretical considerations are confirmed by experimental results. The effect of material parameters and technology on the contrast ratio and display dynamics is given. The effect in TN display with black dye is presented.

JSXGraph--Dynamic Mathematics with JavaScript

ERIC Educational Resources Information Center

Gerhauser, Michael; Valentin, Bianca; Wassermann, Alfred

2010-01-01

Since Java applets seem to be on the retreat in web application, other approaches for displaying interactive mathematics in the web browser are needed. One such alternative could be our open-source project JSXGraph. It is a cross-browser library for displaying interactive geometry, function plotting, graphs, and data visualization in a web…

Group Mirrors to Support Interaction Regulation in Collaborative Problem Solving

ERIC Educational Resources Information Center

Jermann, Patrick; Dillenbourg, Pierre

2008-01-01

Two experimental studies test the effect of group mirrors upon quantitative and qualitative aspects of participation in collaborative problem solving. Mirroring tools consist of a graphical representation of the group's actions which is dynamically updated and displayed to the collaborators. In addition, metacognitive tools display a standard for…

Techniques for optimizing human-machine information transfer related to real-time interactive display systems

NASA Technical Reports Server (NTRS)

Granaas, Michael M.; Rhea, Donald C.

1989-01-01

The requirements for the development of real-time displays are reviewed. Of particular interest are the psychological aspects of design such as the layout, color selection, real-time response rate, and the interactivity of displays. Some existing Western Aeronautical Test Range displays are analyzed.

Color appearance for photorealistic image synthesis

NASA Astrophysics Data System (ADS)

Marini, Daniele; Rizzi, Alessandro; Rossi, Maurizio

2000-12-01

Photorealistic Image Synthesis is a relevant research and application field in computer graphics, whose aim is to produce synthetic images that are undistinguishable from real ones. Photorealism is based upon accurate computational models of light material interaction, that allow us to compute the spectral intensity light field of a geometrically described scene. The fundamental methods are ray tracing and radiosity. While radiosity allows us to compute the diffuse component of the emitted and reflected light, applying ray tracing in a two pass solution we can also cope with non diffuse properties of the model surfaces. Both methods can be implemented to generate an accurate photometric distribution of light of the simulated environment. A still open problem is the visualization phase, whose purpose is to display the final result of the simulated mode on a monitor screen or on a printed paper. The tone reproduction problem consists of finding the best solution to compress the extended dynamic range of the computed light field into the limited range of the displayable colors. Recently some scholars have addressed this problem considering the perception stage of image formation, so including a model of the human visual system in the visualization process. In this paper we present a working hypothesis to solve the tone reproduction problem of synthetic image generation, integrating Retinex perception model into the photo realistic image synthesis context.

Local adaptive tone mapping for video enhancement

NASA Astrophysics Data System (ADS)

Lachine, Vladimir; Dai, Min (.

2015-03-01

As new technologies like High Dynamic Range cameras, AMOLED and high resolution displays emerge on consumer electronics market, it becomes very important to deliver the best picture quality for mobile devices. Tone Mapping (TM) is a popular technique to enhance visual quality. However, the traditional implementation of Tone Mapping procedure is limited by pixel's value to value mapping, and the performance is restricted in terms of local sharpness and colorfulness. To overcome the drawbacks of traditional TM, we propose a spatial-frequency based framework in this paper. In the proposed solution, intensity component of an input video/image signal is split on low pass filtered (LPF) and high pass filtered (HPF) bands. Tone Mapping (TM) function is applied to LPF band to improve the global contrast/brightness, and HPF band is added back afterwards to keep the local contrast. The HPF band may be adjusted by a coring function to avoid noise boosting and signal overshooting. Colorfulness of an original image may be preserved or enhanced by chroma components correction by means of saturation function. Localized content adaptation is further improved by dividing an image to a set of non-overlapped regions and modifying each region individually. The suggested framework allows users to implement a wide range of tone mapping applications with perceptional local sharpness and colorfulness preserved or enhanced. Corresponding hardware circuit may be integrated in camera, video or display pipeline with minimal hardware budget

Computation of Cavitating Flow in a Francis Hydroturbine

NASA Astrophysics Data System (ADS)

Leonard, Daniel; Lindau, Jay

2013-11-01

In an effort to improve cavitation characteristics at off-design conditions, a steady, periodic, multiphase, RANS CFD study of an actual Francis hydroturbine was conducted and compared to experimental results. It is well-known that operating hydroturbines at off-design conditions usually results in the formation of large-scale vaporous cavities. These cavities, and their subsequent collapse, reduce efficiency and cause damage and wear to surfaces. The conventional hydro community has expressed interest in increasing their turbine's operating ranges, improving their efficiencies, and reducing damage and wear to critical turbine components. In this work, mixing planes were used to couple rotating and stationary stages of the turbine which have non-multiple periodicity, and provide a coupled solution for the stay vanes, wicket gates, runner blades, and draft tube. The mixture approach is used to simulate the multiphase flow dynamics, and cavitation models were employed to govern the mass transfer between liquid and gas phases. The solution is compared with experimental results across a range of cavitation numbers which display all the major cavitation features in the machine. Unsteady computations are necessary to capture inherently unsteady cavitation phenomena, such as the precessing vortex rope, and the shedding of bubbles from the wicket gates and their subsequent impingement upon the leading edge of the runner blades. To display these features, preliminary unsteady simulations of the full machine are also presented.

Techniques for optimizing human-machine information transfer related to real-time interactive display systems

NASA Technical Reports Server (NTRS)

Granaas, Michael M.; Rhea, Donald C.

1989-01-01

In recent years the needs of ground-based researcher-analysts to access real-time engineering data in the form of processed information has expanded rapidly. Fortunately, the capacity to deliver that information has also expanded. The development of advanced display systems is essential to the success of a research test activity. Those developed at the National Aeronautics and Space Administration (NASA), Western Aeronautical Test Range (WATR), range from simple alphanumerics to interactive mapping and graphics. These unique display systems are designed not only to meet basic information display requirements of the user, but also to take advantage of techniques for optimizing information display. Future ground-based display systems will rely heavily not only on new technologies, but also on interaction with the human user and the associated productivity with that interaction. The psychological abilities and limitations of the user will become even more important in defining the difference between a usable and a useful display system. This paper reviews the requirements for development of real-time displays; the psychological aspects of design such as the layout, color selection, real-time response rate, and interactivity of displays; and an analysis of some existing WATR displays.

Dynamic lens and monovision 3D displays to improve viewer comfort.

PubMed

Johnson, Paul V; Parnell, Jared Aq; Kim, Joohwan; Saunter, Christopher D; Love, Gordon D; Banks, Martin S

2016-05-30

Stereoscopic 3D (S3D) displays provide an additional sense of depth compared to non-stereoscopic displays by sending slightly different images to the two eyes. But conventional S3D displays do not reproduce all natural depth cues. In particular, focus cues are incorrect causing mismatches between accommodation and vergence: The eyes must accommodate to the display screen to create sharp retinal images even when binocular disparity drives the eyes to converge to other distances. This mismatch causes visual discomfort and reduces visual performance. We propose and assess two new techniques that are designed to reduce the vergence-accommodation conflict and thereby decrease discomfort and increase visual performance. These techniques are much simpler to implement than previous conflict-reducing techniques. The first proposed technique uses variable-focus lenses between the display and the viewer's eyes. The power of the lenses is yoked to the expected vergence distance thereby reducing the mismatch between vergence and accommodation. The second proposed technique uses a fixed lens in front of one eye and relies on the binocularly fused percept being determined by one eye and then the other, depending on simulated distance. We conducted performance tests and discomfort assessments with both techniques and compared the results to those of a conventional S3D display. The first proposed technique, but not the second, yielded clear improvements in performance and reductions in discomfort. This dynamic-lens technique therefore offers an easily implemented technique for reducing the vergence-accommodation conflict and thereby improving viewer experience.

Accessibility Attributes of Blood Glucose Meter and Home Blood Pressure Monitor Displays for Visually Impaired Persons

PubMed Central

Blubaugh, Morgan V.; Uslan, Mark M.

2012-01-01

The vast majority of diabetes-related self-management technology utilizes small visual displays (SVDs) that often produce a low level of contrast and suffer from high levels of reflection (glare). This is a major accessibility issue for the 3.5 million Americans with diabetes who have reduced vision. The purpose of this article is to gather comparative data on the key display attributes of the SVDs used in blood glucose meters (BGMs) and home blood pressure monitors (HBPMs) on the market today and determine which displays offer the best prospect for being accessible to people with reduced vision. Nine BGMs and eight HBPMs were identified for this study on the basis of amount of devices sold, full-functionality speech output, and advanced display technologies. An optical instrumentation system obtained contrast, reflection (glare), and font height measurements for all 17 displays. The contrast, reflection, and font-height values for the BGMs and HBPMs varied greatly between models. The Michelson contrast values for the BGMs ranged from 11% to 98% and font heights ranged 0.39–1.00 in. for the measurement results. The HBPMs had Michelson contrast values ranging 55–96% and font height ranging 0.28–0.94 in. for the measurement results. Due largely to the lack of display design standards for the technical requirements of SVDs, there is tremendous variability in the quality and readability of BGM and HBPM displays. There were two BGMs and one HBPM that exhibited high-contrast values and large font heights, but most of the devices exhibited either poor contrast or exceptionally high reflection. PMID:22538132

Accessibility attributes of blood glucose meter and home blood pressure monitor displays for visually impaired persons.

PubMed

Blubaugh, Morgan V; Uslan, Mark M

2012-03-01

The vast majority of diabetes-related self-management technology utilizes small visual displays (SVDs) that often produce a low level of contrast and suffer from high levels of reflection (glare). This is a major accessibility issue for the 3.5 million Americans with diabetes who have reduced vision. The purpose of this article is to gather comparative data on the key display attributes of the SVDs used in blood glucose meters (BGMs) and home blood pressure monitors (HBPMs) on the market today and determine which displays offer the best prospect for being accessible to people with reduced vision. Nine BGMs and eight HBPMs were identified for this study on the basis of amount of devices sold, fullfunctionality speech output, and advanced display technologies. An optical instrumentation system obtained contrast, reflection (glare), and font height measurements for all 17 displays. The contrast, reflection, and font-height values for the BGMs and HBPMs varied greatly between models. The Michelson contrast values for the BGMs ranged from 11% to 98% and font heights ranged 0.39-1.00 in. for the measurement results. The HBPMs had Michelson contrast values ranging 55-96% and font height ranging 0.28-0.94 in. for the measurement results. Due largely to the lack of display design standards for the technical requirements of SVDs, there is tremendous variability in the quality and readability of BGM and HBPM displays. There were two BGMs and one HBPM that exhibited high-contrast values and large font heights, but most of the devices exhibited either poor contrast or exceptionally high reflection. © 2012 Diabetes Technology Society.

A manned maneuvering unit proximity operations planning and flight guidance display and control system

NASA Technical Reports Server (NTRS)

Gershzohn, Gary R.; Sirko, Robert J.; Zimmerman, K.; Jones, A. D.

1990-01-01

This task concerns the design, development, testing, and evaluation of a new proximity operations planning and flight guidance display and control system for manned space operations. A forecast, derivative manned maneuvering unit (MMU) was identified as a candidate for the application of a color, highway-in-the-sky display format for the presentation of flight guidance information. A silicon graphics 4D/20-based simulation is being developed to design and test display formats and operations concepts. The simulation includes the following: (1) real-time color graphics generation to provide realistic, dynamic flight guidance displays and control characteristics; (2) real-time graphics generation of spacecraft trajectories; (3) MMU flight dynamics and control characteristics; (4) control algorithms for rotational and translational hand controllers; (5) orbital mechanics effects for rendezvous and chase spacecraft; (6) inclusion of appropriate navigation aids; and (7) measurement of subject performance. The flight planning system under development provides for: (1) selection of appropriate operational modes, including minimum cost, optimum cost, minimum time, and specified ETA; (2) automatic calculation of rendezvous trajectories, en route times, and fuel requirements; (3) and provisions for manual override. Man/machine function allocations in planning and en route flight segments are being evaluated. Planning and en route data are presented on one screen composed of two windows: (1) a map display presenting a view perpendicular to the orbital plane, depicting flight planning trajectory and time data attitude display presenting attitude and course data for use en route; and (2) an attitude display presenting local vertical-local horizontal attitude data superimposed on a highway-in-the-sky or flight channel representation of the flight planned course. Both display formats are presented while the MMU is en route. In addition to these displays, several original display elements are being developed, including a 3DOF flight detector for attitude commanding, a different flight detector for translation commands, and a pictorial representation of velocity deviations.

Ultrafast rotation in an amphidynamic crystalline metal organic framework

DOE PAGES

Vogelsberg, Cortnie S.; Uribe-Romo, Fernando J.; Lipton, Andrew S.; ...

2017-12-26

Amphidynamic crystals are an emergent class of condensed phase matter designed with a combination of lattice-forming elements linked to components that display engineered dynamics in the solid state. Here, we address the design of a crystalline array of molecular rotors with inertial diffusional rotation at the nanoscale, characterized by the absence of steric or electronic barriers. We solved this challenge with 1,4-bicyclo[2.2.2]octane dicarboxylic acid (BODCA)-MOF, a metal-organic framework (MOF) built with a high-symmetry bicyclo[2.2.2]octane dicarboxylate linker in a Zn 4O cubic lattice. Using spin-lattice relaxation 1H solid-state NMR at 29.49 and 13.87 MHz in the temperature range of 2.3–80 K,more » we showed that internal rotation occurs in a potential with energy barriers of 0.185 kcal mol -1. These results were confirmed with 2H solid-state NMR line-shape analysis and spin-lattice relaxation at 76.78 MHz obtained between 6 and 298 K, which, combined with molecular dynamics simulations, indicate that inertial diffusional rotation is characterized by a broad range of angular displacements with no residence time at any given site. Furthermore, the ambient temperature rotation of the bicyclo[2.2.2]octane (BCO) group in BODCA-MOF constitutes an example where engineered rotational dynamics in the solid state are as fast as they would be in a high-density gas or in a low-density liquid phase.« less

Ultrafast rotation in an amphidynamic crystalline metal organic framework

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

Vogelsberg, Cortnie S.; Uribe-Romo, Fernando J.; Lipton, Andrew S.

Amphidynamic crystals are an emergent class of condensed phase matter designed with a combination of lattice-forming elements linked to components that display engineered dynamics in the solid state. Here, we address the design of a crystalline array of molecular rotors with inertial diffusional rotation at the nanoscale, characterized by the absence of steric or electronic barriers. We solved this challenge with 1,4-bicyclo[2.2.2]octane dicarboxylic acid (BODCA)-MOF, a metal-organic framework (MOF) built with a high-symmetry bicyclo[2.2.2]octane dicarboxylate linker in a Zn 4O cubic lattice. Using spin-lattice relaxation 1H solid-state NMR at 29.49 and 13.87 MHz in the temperature range of 2.3–80 K,more » we showed that internal rotation occurs in a potential with energy barriers of 0.185 kcal mol -1. These results were confirmed with 2H solid-state NMR line-shape analysis and spin-lattice relaxation at 76.78 MHz obtained between 6 and 298 K, which, combined with molecular dynamics simulations, indicate that inertial diffusional rotation is characterized by a broad range of angular displacements with no residence time at any given site. Furthermore, the ambient temperature rotation of the bicyclo[2.2.2]octane (BCO) group in BODCA-MOF constitutes an example where engineered rotational dynamics in the solid state are as fast as they would be in a high-density gas or in a low-density liquid phase.« less

X-33 Telemetry Best Source Selection, Processing, Display, and Simulation Model Comparison

NASA Technical Reports Server (NTRS)

Burkes, Darryl A.

1998-01-01

The X-33 program requires the use of multiple telemetry ground stations to cover the launch, ascent, transition, descent, and approach phases for the flights from Edwards AFB to landings at Dugway Proving Grounds, UT and Malmstrom AFB, MT. This paper will discuss the X-33 telemetry requirements and design, including information on fixed and mobile telemetry systems, best source selection, and support for Range Safety Officers. A best source selection system will be utilized to automatically determine the best source based on the frame synchronization status of the incoming telemetry streams. These systems will be used to select the best source at the landing sites and at NASA Dryden Flight Research Center to determine the overall best source between the launch site, intermediate sites, and landing site sources. The best source at the landing sites will be decommutated to display critical flight safety parameters for the Range Safety Officers. The overall best source will be sent to the Lockheed Martin's Operational Control Center at Edwards AFB for performance monitoring by X-33 program personnel and for monitoring of critical flight safety parameters by the primary Range Safety Officer. The real-time telemetry data (received signal strength, etc.) from each of the primary ground stations will also be compared during each nu'ssion with simulation data generated using the Dynamic Ground Station Analysis software program. An overall assessment of the accuracy of the model will occur after each mission. Acknowledgment: The work described in this paper was NASA supported through cooperative agreement NCC8-115 with Lockheed Martin Skunk Works.

Accurate Structural Correlations from Maximum Likelihood Superpositions

PubMed Central

Theobald, Douglas L; Wuttke, Deborah S

2008-01-01

The cores of globular proteins are densely packed, resulting in complicated networks of structural interactions. These interactions in turn give rise to dynamic structural correlations over a wide range of time scales. Accurate analysis of these complex correlations is crucial for understanding biomolecular mechanisms and for relating structure to function. Here we report a highly accurate technique for inferring the major modes of structural correlation in macromolecules using likelihood-based statistical analysis of sets of structures. This method is generally applicable to any ensemble of related molecules, including families of nuclear magnetic resonance (NMR) models, different crystal forms of a protein, and structural alignments of homologous proteins, as well as molecular dynamics trajectories. Dominant modes of structural correlation are determined using principal components analysis (PCA) of the maximum likelihood estimate of the correlation matrix. The correlations we identify are inherently independent of the statistical uncertainty and dynamic heterogeneity associated with the structural coordinates. We additionally present an easily interpretable method (“PCA plots”) for displaying these positional correlations by color-coding them onto a macromolecular structure. Maximum likelihood PCA of structural superpositions, and the structural PCA plots that illustrate the results, will facilitate the accurate determination of dynamic structural correlations analyzed in diverse fields of structural biology. PMID:18282091

Dynamic feature analysis for Voyager at the Image Processing Laboratory

NASA Technical Reports Server (NTRS)

Yagi, G. M.; Lorre, J. J.; Jepsen, P. L.

1978-01-01

Voyager 1 and 2 were launched from Cape Kennedy to Jupiter, Saturn, and beyond on September 5, 1977 and August 20, 1977. The role of the Image Processing Laboratory is to provide the Voyager Imaging Team with the necessary support to identify atmospheric features (tiepoints) for Jupiter and Saturn data, and to analyze and display them in a suitable form. This support includes the software needed to acquire and store tiepoints, the hardware needed to interactively display images and tiepoints, and the general image processing environment necessary for decalibration and enhancement of the input images. The objective is an understanding of global circulation in the atmospheres of Jupiter and Saturn. Attention is given to the Voyager imaging subsystem, the Voyager imaging science objectives, hardware, software, display monitors, a dynamic feature study, decalibration, navigation, and data base.

Nonlinear oscillations in a muscle pacemaker cell model

NASA Astrophysics Data System (ADS)

González-Miranda, J. M.

2017-02-01

This article presents a numerical simulation study of the nonlinear oscillations displayed by the Morris-Lecar model [Biophys. J. 35 (1981) 193] for the oscillations experimentally observed in the transmembrane potential of a muscle fiber subject to an external electrical stimulus. We consider the model in the case when there is no external stimulation, aiming to establish the ability of the model to display biophysically reasonable pacemaker dynamics. We obtain 2D bifurcation diagrams showing that indeed the model presents oscillatory dynamics, displaying the two main types of action potentials that are observed in muscle fibers. The results obtained are shown to be structurally stable; that is, robust against changes in the values of system parameters. Moreover, it is demonstrated how the model is appropriate to analyze the action potentials observed in terms of the transmembrane currents creating them.

Method of improving a digital image

NASA Technical Reports Server (NTRS)

Jobson, Daniel J. (Inventor); Woodell, Glenn A. (Inventor); Rahman, Zia-ur (Inventor)

1999-01-01

A method of improving a digital image is provided. The image is initially represented by digital data indexed to represent positions on a display. The digital data is indicative of an intensity value I.sub.i (x,y) for each position (x,y) in each i-th spectral band. The intensity value for each position in each i-th spectral band is adjusted to generate an adjusted intensity value for each position in each i-th spectral band in accordance with ##EQU1## where S is the number of unique spectral bands included in said digital data, W.sub.n is a weighting factor and * denotes the convolution operator. Each surround function F.sub.n (x,y) is uniquely scaled to improve an aspect of the digital image, e.g., dynamic range compression, color constancy, and lightness rendition. The adjusted intensity value for each position in each i-th spectral band is filtered with a common function and then presented to a display device. For color images, a novel color restoration step is added to give the image true-to-life color that closely matches human observation.

Lidar measurements of wildfire smoke aerosols in the atmosphere above Sofia, Bulgaria

NASA Astrophysics Data System (ADS)

Peshev, Zahary Y.; Deleva, Atanaska D.; Dreischuh, Tanja N.; Stoyanov, Dimitar V.

2016-01-01

Presented are results of lidar measurements and characterization of wildfire caused smoke aerosols observed in the atmosphere above the city of Sofia, Bulgaria, related to two local wildfires raging in forest areas near the city. A lidar systems based on a frequency-doubled Nd:YAG laser operated at 532 nm and 1064 nm is used in the smoke aerosol observations. It belongs to the Sofia LIDAR Station (at Laser Radars Laboratory, Institute of Electronics, Bulgarian Academy of Sciences), being a part of the European Aerosol Lidar Network. Optical, dynamical, microphysical, and geometrical properties and parameters of the observed smoke aerosol particles and layers are displayed and analyzed, such as: range/height-resolved profiles of the aerosol backscatter coefficient; integral aerosol backscattering; sets of colormaps displaying time series of the height distribution of the aerosol density; topologic, geometric, and volumetric properties of the smoke aerosol layers; time-averaged height profiles of backscatter-related Ångström exponent (BAE). Obtained results of retrieving and profiling smoke aerosols are commented in their relations to available meteorological and air-mass-transport forecasting and modelling data.

Atomic-level molybdenum oxide nanorings with full-spectrum absorption and photoresponsive properties.

PubMed

Yang, Yong; Yang, Yang; Chen, Shuangming; Lu, Qichen; Song, Li; Wei, Yen; Wang, Xun

2017-11-16

Superthin nanostructures, particularly with atomic-level thicknesses, typically display unique optical properties because of their exceptional light-matter interactions. Here, we report a facile strategy for the synthesis of sulfur-doped molybdenum oxide nanorings with an atomic-level size (thickness of 0.5 nm) and a tunable ring-in-ring architecture. These atomic-level nanorings displayed strong photo-absorption in both the visible and infrared-light ranges and acted as a photothermal agent. Under irradiation with an 808 nm laser with an intensity of 1 W/cm 2 , a composite of the nanorings embedded in polydimethylsiloxane showed an ultrafast photothermal effect, delivering a local temperature of up to 400 °C within 20 s, which to the best of our knowledge is the highest temperature by light irradiation reported to date. Meanwhile, the resulting nanorings were also employed as a photoinitiator to remotely induce a visible-light shape memory response, self-healing, reshaping performance and reversible actuation of dynamic three-dimensional structures. This study demonstrates an advancement towards controlling atomic-level-sized nanostructures and achieving greatly enhanced optical performances for optoelectronics.

A real-time electronic imaging system for solar X-ray observations from sounding rockets

NASA Technical Reports Server (NTRS)

Davis, J. M.; Ting, J. W.; Gerassimenko, M.

1979-01-01

A real-time imaging system for displaying the solar coronal soft X-ray emission, focussed by a grazing incidence telescope, is described. The design parameters of the system, which is to be used primarily as part of a real-time control system for a sounding rocket experiment, are identified. Their achievement with a system consisting of a microchannel plate, for the conversion of X-rays into visible light, and a slow-scan vidicon, for recording and transmission of the integrated images, is described in detail. The system has a quantum efficiency better than 8 deg above 8 A, a dynamic range of 1000 coupled with a sensitivity to single photoelectrons, and provides a spatial resolution of 15 arc seconds over a field of view of 40 x 40 square arc minutes. The incident radiation is filtered to eliminate wavelengths longer than 100 A. Each image contains 3.93 x 10 to the 5th bits of information and is transmitted to the ground where it is processed by a mini-computer and displayed in real-time on a standard TV monitor.

Low-cost soft-copy display accuracy in the detection of pulmonary nodules by single-exposure dual-energy subtraction: comparison with hard-copy viewing.

PubMed

Kido, S; Kuriyama, K; Hosomi, N; Inoue, E; Kuroda, C; Horai, T

2000-02-01

This study endeavored to clarify the usefulness of single-exposure dual-energy subtraction computed radiography (CR) of the chest and the ability of soft-copy images to detect low-contrast simulated pulmonary nodules. Conventional and bone-subtracted CR images of 25 chest phantom image sets with a low-contrast nylon nodule and 25 without a nodule were interpreted by 12 observers (6 radiologists, 6 chest physicians) who rated each on a continuous confidence scale and marked the position of the nodule if one was present. Hard-copy images were 7 x 7-inch laser-printed CR films, and soft-copy images were displayed on a 21-inch noninterlaced color CRT monitor with an optimized dynamic range. Soft-copy images were adjusted to the same size as hard-copy images and were viewed under darkened illumination in the reading room. No significant differences were found between hard- and soft-copy images. In conclusion, the soft-copy images were found to be useful in detecting low-contrast simulated pulmonary nodules.

Transient Dynamic Mechanical Analysis of Resilin-based Elastomeric Hydrogels

NASA Astrophysics Data System (ADS)

Li, Linqing; Kiick, Kristi

2014-04-01

The outstanding high-frequency properties of emerging resilin-like polypeptides (RLPs) have motivated their development for vocal fold tissue regeneration and other applications. Recombinant RLP hydrogels show efficient gelation, tunable mechanical properties, and display excellent extensibility, but little has been reported about their transient mechanical properties. In this manuscript, we describe the transient mechanical behavior of new RLP hydrogels investigated via both sinusoidal oscillatory shear deformation and uniaxial tensile testing. Oscillatory stress relaxation and creep experiments confirm that RLP-based hydrogels display significantly reduced stress relaxation and improved strain recovery compared to PEG-based control hydrogels. Uniaxial tensile testing confirms the negligible hysteresis, reversible elasticity and superior resilience (up to 98%) of hydrated RLP hydrogels, with Young’s modulus values that compare favorably with those previously reported for resilin and that mimic the tensile properties of the vocal fold ligament at low strain (< 15%). These studies expand our understanding of the properties of these RLP materials under a variety of conditions, and confirm the unique applicability, for mechanically demanding tissue engineering applications, of a range of RLP hydrogels.

Experimental Studies of Intent Information on Cockpit Traffic Displays

NASA Technical Reports Server (NTRS)

Barhydt, Richard; Hansman, R. John, Jr.

1997-01-01

Intent information provides knowledge of another aircraft's current and future trajectory states. Prototype traffic displays were designed for four different levels of intent: No Intent, Rate, Commanded State, and Flight Management System (FMS)-Path. The TCAS Display was used as a baseline and represents the No Intent Level. The Rate, Commanded State, and FMS-Path Displays show increasing levels of intent information using TCAS-like symbology in addition to incorporating a conflict probe and profile view display. An experiment was run on the MIT Part Task Flight Simulator in which eight airline pilots flew five traffic scenarios with each of the four displays. Results show that pilots had fewer separation violations and maneuvered earlier with the three intent displays. Separation violations were reduced when pilots maneuvered earlier. A second experiment was run to compare performance between displaying intent information directly and incorporating it into a conflict probe. A different set of eight airline pilots flew four traffic scenarios with the TCAS and Commanded State Displays with and without the conflict probe. Conflict probes with two minute and long range look-ahead times were tested. Displaying conflict bands or showing intent information directly both led to fewer separation violations and earlier avoidance maneuvers than the base TCAS Display. Performance was similar between the two minute and long range look-ahead conflict probes. Pilots preferred all intent displays over the TCAS Display.

Aging and the rate of visual information processing.

PubMed

Guest, Duncan; Howard, Christina J; Brown, Louise A; Gleeson, Harriet

2015-01-01

Multiple methods exist for measuring how age influences the rate of visual information processing. The most advanced methods model the processing dynamics in a task in order to estimate processing rates independently of other factors that might be influenced by age, such as overall performance level and the time at which processing onsets. However, such modeling techniques have produced mixed evidence for age effects. Using a time-accuracy function (TAF) analysis, Kliegl, Mayr, and Krampe (1994) showed clear evidence for age effects on processing rate. In contrast, using the diffusion model to examine the dynamics of decision processes, Ratcliff and colleagues (e.g., Ratcliff, Thapar, & McKoon, 2006) found no evidence for age effects on processing rate across a range of tasks. Examination of these studies suggests that the number of display stimuli might account for the different findings. In three experiments we measured the precision of younger and older adults' representations of target stimuli after different amounts of stimulus exposure. A TAF analysis found little evidence for age differences in processing rate when a single stimulus was presented (Experiment 1). However, adding three nontargets to the display resulted in age-related slowing of processing (Experiment 2). Similar slowing was observed when simply presenting two stimuli and using a post-cue to indicate the target (Experiment 3). Although there was some interference from distracting objects and from previous responses, these age-related effects on processing rate seem to reflect an age-related difficulty in processing multiple objects, particularly when encoding them into visual working memory.

TRPM8-Dependent Dynamic Response in a Mathematical Model of Cold Thermoreceptor

PubMed Central

Olivares, Erick; Salgado, Simón; Maidana, Jean Paul; Herrera, Gaspar; Campos, Matías; Madrid, Rodolfo; Orio, Patricio

2015-01-01

Cold-sensitive nerve terminals (CSNTs) encode steady temperatures with regular, rhythmic temperature-dependent firing patterns that range from irregular tonic firing to regular bursting (static response). During abrupt temperature changes, CSNTs show a dynamic response, transiently increasing their firing frequency as temperature decreases and silencing when the temperature increases (dynamic response). To date, mathematical models that simulate the static response are based on two depolarizing/repolarizing pairs of membrane ionic conductance (slow and fast kinetics). However, these models fail to reproduce the dynamic response of CSNTs to rapid changes in temperature and notoriously they lack a specific cold-activated conductance such as the TRPM8 channel. We developed a model that includes TRPM8 as a temperature-dependent conductance with a calcium-dependent desensitization. We show by computer simulations that it appropriately reproduces the dynamic response of CSNTs from mouse cornea, while preserving their static response behavior. In this model, the TRPM8 conductance is essential to display a dynamic response. In agreement with experimental results, TRPM8 is also needed for the ongoing activity in the absence of stimulus (i.e. neutral skin temperature). Free parameters of the model were adjusted by an evolutionary optimization algorithm, allowing us to find different solutions. We present a family of possible parameters that reproduce the behavior of CSNTs under different temperature protocols. The detection of temperature gradients is associated to a homeostatic mechanism supported by the calcium-dependent desensitization. PMID:26426259

The Stationary-Phase Cells of Saccharomyces cerevisiae Display Dynamic Actin Filaments Required for Processes Extending Chronological Life Span.

PubMed

Vasicova, Pavla; Lejskova, Renata; Malcova, Ivana; Hasek, Jiri

2015-11-01

Stationary-growth-phase Saccharomyces cerevisiae yeast cultures consist of nondividing cells that undergo chronological aging. For their successful survival, the turnover of proteins and organelles, ensured by autophagy and the activation of mitochondria, is performed. Some of these processes are engaged in by the actin cytoskeleton. In S. cerevisiae stationary-phase cells, F actin has been shown to form static aggregates named actin bodies, subsequently cited to be markers of quiescence. Our in vivo analyses revealed that stationary-phase cultures contain cells with dynamic actin filaments, besides the cells with static actin bodies. The cells with dynamic actin displayed active endocytosis and autophagy and well-developed mitochondrial networks. Even more, stationary-phase cell cultures grown under calorie restriction predominantly contained cells with actin cables, confirming that the presence of actin cables is linked to successful adaptation to stationary phase. Cells with actin bodies were inactive in endocytosis and autophagy and displayed aberrations in mitochondrial networks. Notably, cells of the respiratory activity-deficient cox4Δ strain displayed the same mitochondrial aberrations and actin bodies only. Additionally, our results indicate that mitochondrial dysfunction precedes the formation of actin bodies and the appearance of actin bodies corresponds to decreased cell fitness. We conclude that the F-actin status reflects the extent of damage that arises from exponential growth. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The Stationary-Phase Cells of Saccharomyces cerevisiae Display Dynamic Actin Filaments Required for Processes Extending Chronological Life Span

PubMed Central

Lejskova, Renata; Malcova, Ivana

2015-01-01

Stationary-growth-phase Saccharomyces cerevisiae yeast cultures consist of nondividing cells that undergo chronological aging. For their successful survival, the turnover of proteins and organelles, ensured by autophagy and the activation of mitochondria, is performed. Some of these processes are engaged in by the actin cytoskeleton. In S. cerevisiae stationary-phase cells, F actin has been shown to form static aggregates named actin bodies, subsequently cited to be markers of quiescence. Our in vivo analyses revealed that stationary-phase cultures contain cells with dynamic actin filaments, besides the cells with static actin bodies. The cells with dynamic actin displayed active endocytosis and autophagy and well-developed mitochondrial networks. Even more, stationary-phase cell cultures grown under calorie restriction predominantly contained cells with actin cables, confirming that the presence of actin cables is linked to successful adaptation to stationary phase. Cells with actin bodies were inactive in endocytosis and autophagy and displayed aberrations in mitochondrial networks. Notably, cells of the respiratory activity-deficient cox4Δ strain displayed the same mitochondrial aberrations and actin bodies only. Additionally, our results indicate that mitochondrial dysfunction precedes the formation of actin bodies and the appearance of actin bodies corresponds to decreased cell fitness. We conclude that the F-actin status reflects the extent of damage that arises from exponential growth. PMID:26351139

Overview of fast algorithm in 3D dynamic holographic display

NASA Astrophysics Data System (ADS)

Liu, Juan; Jia, Jia; Pan, Yijie; Wang, Yongtian

2013-08-01

3D dynamic holographic display is one of the most attractive techniques for achieving real 3D vision with full depth cue without any extra devices. However, huge 3D information and data should be preceded and be computed in real time for generating the hologram in 3D dynamic holographic display, and it is a challenge even for the most advanced computer. Many fast algorithms are proposed for speeding the calculation and reducing the memory usage, such as:look-up table (LUT), compressed look-up table (C-LUT), split look-up table (S-LUT), and novel look-up table (N-LUT) based on the point-based method, and full analytical polygon-based methods, one-step polygon-based method based on the polygon-based method. In this presentation, we overview various fast algorithms based on the point-based method and the polygon-based method, and focus on the fast algorithm with low memory usage, the C-LUT, and one-step polygon-based method by the 2D Fourier analysis of the 3D affine transformation. The numerical simulations and the optical experiments are presented, and several other algorithms are compared. The results show that the C-LUT algorithm and the one-step polygon-based method are efficient methods for saving calculation time. It is believed that those methods could be used in the real-time 3D holographic display in future.

Application of a minicomputer-based system in measuring intraocular fluid dynamics

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

Bronzino, J.D.; D'Amato, D.P.; O'Rourke, J.

A complete, computerized system has been developed to automate and display radionuclide clearance studies in an ophthalmology clinical laboratory. The system is based on a PDP-8E computer with a 16-k core memory and includes a dual-drive Decassette system and an interactive display terminal. The software controls the acquisition of data from an NIM scaler, times the procedures, and analyzes and simultaneously displays logarithmically converted data on a fully annotated graph. Animal studies and clinical experiments are presented to illustrate the nature of these displays and the results obtained using this automated eye physiometer.

Spatiotemporal evolution in a (2+1)-dimensional chemotaxis model

NASA Astrophysics Data System (ADS)

Banerjee, Santo; Misra, Amar P.; Rondoni, L.

2012-01-01

Simulations are performed to investigate the nonlinear dynamics of a (2+1)-dimensional chemotaxis model of Keller-Segel (KS) type, with a logistic growth term. Because of its ability to display auto-aggregation, the KS model has been widely used to simulate self-organization in many biological systems. We show that the corresponding dynamics may lead to steady-states, to divergencies in a finite time as well as to the formation of spatiotemporal irregular patterns. The latter, in particular, appears to be chaotic in part of the range of bounded solutions, as demonstrated by the analysis of wavelet power spectra. Steady-states are achieved with sufficiently large values of the chemotactic coefficient (χ) and/or with growth rates r below a critical value rc. For r>rc, the solutions of the differential equations of the model diverge in a finite time. We also report on the pattern formation regime, for different values of χ, r and of the diffusion coefficient D.

Squids old and young: Scale-free design for a simple billboard

NASA Astrophysics Data System (ADS)

Packard, Andrew

2011-03-01

Squids employ a large range of brightness-contrast spatial frequencies in their camouflage and signalling displays. The 'billboard' of coloured elements ('spots'=chromatophore organs) in the skin is built autopoietically-probably by lateral inhibitory processes-and enlarges as much as 10,000-fold during development. The resulting two-dimensional array is a fractal-like colour/size hierarchy lying in several layers of a multilayered network. Dynamic control of the array by muscles and nerves produces patterns that recall 'half-tone' processing (cf. ink-jet printer). In the more sophisticated (loliginid) squids, patterns also combine 'continuous tones' (cf. dye-sublimation printer). Physiologists and engineers can exploit the natural colour-coding of the integument to understand nerve and muscle system dynamics, examined here at the level of the ensemble. Integrative functions of the whole (H) are analysed in terms of the power spectrum within and between ensembles and of spontaneous waves travelling through the billboard. Video material may be obtained from the author at the above address.

Sunlight readable avionics displays

NASA Astrophysics Data System (ADS)

Visinski, Joseph R.

1998-09-01

The theme of the Cockpit Displays V Conference of 'Custom versus Consumer -- Grade Displays in Defense Applications' reflects the Raytheon Systems Company field emission display (FED) development effort. Raytheon chose to license commercial FED technology and subsequently participate in a commercial industry 'FED Alliance' to insert this technology into commercial and avionics defense applications. The unaffordability of custom military displays makes them an unfeasible choice to build a business upon. The major differences between consumer FEDs and those adapted for military/avionics installations are: (1) high brightness for sunlight visibility; (2) extended environmental range; (3) high resolution; (4) wider dimming range for sunlight to NVIS operation; (5) extended gray scales; (6) lifetime product support well beyond two year consumer market life. The transition to defense applications is further being accomplished via industry/government partnerships as the DARPA Technology Reinvestment Project (TRP) and BAA 97-31. FEDs combine cathode ray tube (CRT) and matrix addressed flat panel display technology, parts, manufacturing, and test equipment, plus open systems interfaces into a new display.

Bursts of activity in collective cell migration

PubMed Central

Chepizhko, Oleksandr; Giampietro, Costanza; Mastrapasqua, Eleonora; Nourazar, Mehdi; Ascagni, Miriam; Sugni, Michela; Fascio, Umberto; Leggio, Livio; Malinverno, Chiara; Scita, Giorgio; Santucci, Stéphane; Alava, Mikko J.; Zapperi, Stefano; La Porta, Caterina A. M.

2016-01-01

Dense monolayers of living cells display intriguing relaxation dynamics, reminiscent of soft and glassy materials close to the jamming transition, and migrate collectively when space is available, as in wound healing or in cancer invasion. Here we show that collective cell migration occurs in bursts that are similar to those recorded in the propagation of cracks, fluid fronts in porous media, and ferromagnetic domain walls. In analogy with these systems, the distribution of activity bursts displays scaling laws that are universal in different cell types and for cells moving on different substrates. The main features of the invasion dynamics are quantitatively captured by a model of interacting active particles moving in a disordered landscape. Our results illustrate that collective motion of living cells is analogous to the corresponding dynamics in driven, but inanimate, systems. PMID:27681632

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

Rivera-Durón, R. R., E-mail: roberto.rivera@ipicyt.edu.mx; Campos-Cantón, E., E-mail: eric.campos@ipicyt.edu.mx; Campos-Cantón, I.

We present the design of an autonomous time-delay Boolean network realized with readily available electronic components. Through simulations and experiments that account for the detailed nonlinear response of each circuit element, we demonstrate that a network with five Boolean nodes displays complex behavior. Furthermore, we show that the dynamics of two identical networks display near-instantaneous synchronization to a periodic state when forced by a common periodic Boolean signal. A theoretical analysis of the network reveals the conditions under which complex behavior is expected in an individual network and the occurrence of synchronization in the forced networks. This research will enablemore » future experiments on autonomous time-delay networks using readily available electronic components with dynamics on a slow enough time-scale so that inexpensive data collection systems can faithfully record the dynamics.« less

Studies of the effects of gravitational and inertial forces on cardiovascular and respiratory dynamics

NASA Technical Reports Server (NTRS)

Wood, E. H.

1972-01-01

Developments in the following areas are discussed: television camera in dynamic angiography, dynamic computer generated displays for study of the human left ventricle, and status report on the work statement for the sixth year. A list of publications for the period 1 October 1971 to 1 October 1972 is included.

Method and system for monitoring and displaying engine performance parameters

NASA Technical Reports Server (NTRS)

Abbott, Terence S. (Inventor); Person, Lee H., Jr. (Inventor)

1988-01-01

The invention is believed a major improvement that will have a broad application in governmental and commercial aviation. It provides a dynamic method and system for monitoring and simultaneously displaying in easily scanned form the available, predicted, and actual thrust of a jet aircraft engine under actual operating conditions. The available and predicted thrusts are based on the performance of a functional model of the aircraft engine under the same operating conditions. Other critical performance parameters of the aircraft engine and functional model are generated and compared, the differences in value being simultaneously displayed in conjunction with the displayed thrust values. Thus, the displayed information permits the pilot to make power adjustments directly while keeping him aware of total performance at a glance of a single display panel.

Lower limb biomechanics during running in individuals with achilles tendinopathy: a systematic review

PubMed Central

2011-01-01

Background Abnormal lower limb biomechanics is speculated to be a risk factor for Achilles tendinopathy. This study systematically reviewed the existing literature to identify, critique and summarise lower limb biomechanical factors associated with Achilles tendinopathy. Methods We searched electronic bibliographic databases (Medline, EMBASE, Current contents, CINAHL and SPORTDiscus) in November 2010. All prospective cohort and case-control studies that evaluated biomechanical factors (temporospatial parameters, lower limb kinematics, dynamic plantar pressures, kinetics [ground reaction forces and joint moments] and muscle activity) associated with mid-portion Achilles tendinopathy were included. Quality of included studies was evaluated using the Quality Index. The magnitude of differences (effect sizes) between cases and controls was calculated using Cohen's d (with 95% CIs). Results Nine studies were identified; two were prospective and the remaining seven case-control study designs. The quality of 9 identified studies was varied, with Quality Index scores ranging from 4 to 15 out of 17. All studies analysed running biomechanics. Cases displayed increased eversion range of motion of the rearfoot (d = 0.92 and 0.67 in two studies), reduced maximum lower leg abduction (d = -1.16), reduced ankle joint dorsiflexion velocity (d = -0.62) and reduced knee flexion during gait (d = -0.90). Cases also demonstrated a number of differences in dynamic plantar pressures (primarily the distribution of the centre of force), ground reaction forces (large effects for timing variables) and also showed reduced peak tibial external rotation moment (d = -1.29). Cases also displayed differences in the timing and amplitude of a number of lower limb muscles but many differences were equivocal. Conclusions There are differences in lower limb biomechanics between those with and without Achilles tendinopathy that may have implications for the prevention and management of the condition. However, the findings need to be interpreted with caution due to the limited quality of a number of the included studies. Future well-designed prospective studies are required to confirm these findings. PMID:21619710

New Force Field Model for Propylene Glycol: Insight to Local Structure and Dynamics.

PubMed

Ferreira, Elisabete S C; Voroshylova, Iuliia V; Koverga, Volodymyr A; Pereira, Carlos M; Cordeiro, M Natália D S

2017-12-07

In this work we developed a new force field model (FFM) for propylene glycol (PG) based on the OPLS all-atom potential. The OPLS potential was refined using quantum chemical calculations, taking into account the densities and self-diffusion coefficients. The validation of this new FFM was carried out based on a wide range of physicochemical properties, such as density, enthalpy of vaporization, self-diffusion coefficients, isothermal compressibility, surface tension, and shear viscosity. The molecular dynamics (MD) simulations were performed over a large range of temperatures (293.15-373.15 K). The comparison with other force field models, such as OPLS, CHARMM27, and GAFF, revealed a large improvement of the results, allowing a better agreement with experimental data. Specific structural properties (radial distribution functions, hydrogen bonding and spatial distribution functions) were then analyzed in order to support the adequacy of the proposed FFM. Pure propylene glycol forms a continuous phase, displaying no microstructures. It is shown that the developed FFM gives rise to suitable results not only for pure propylene glycol but also for mixtures by testing its behavior for a 50 mol % aqueous propylene glycol solution. Furthermore, it is demonstrated that the addition of water to the PG phase produces a homogeneous solution and that the hydration interactions prevail over the propylene glycol self-association interactions.

High-dynamic range imaging techniques based on both color-separation algorithms used in conventional graphic arts and the human visual perception modeling

NASA Astrophysics Data System (ADS)

Lo, Mei-Chun; Hsieh, Tsung-Hsien; Perng, Ruey-Kuen; Chen, Jiong-Qiao

2010-01-01

The aim of this research is to derive illuminant-independent type of HDR imaging modules which can optimally multispectrally reconstruct of every color concerned in high-dynamic-range of original images for preferable cross-media color reproduction applications. Each module, based on either of broadband and multispectral approach, would be incorporated models of perceptual HDR tone-mapping, device characterization. In this study, an xvYCC format of HDR digital camera was used to capture HDR scene images for test. A tone-mapping module was derived based on a multiscale representation of the human visual system and used equations similar to a photoreceptor adaptation equation, proposed by Michaelis-Menten. Additionally, an adaptive bilateral type of gamut mapping algorithm, using approach of a multiple conversing-points (previously derived), was incorporated with or without adaptive Un-sharp Masking (USM) to carry out the optimization of HDR image rendering. An LCD with standard color space of Adobe RGB (D65) was used as a soft-proofing platform to display/represent HDR original RGB images, and also evaluate both renditionquality and prediction-performance of modules derived. Also, another LCD with standard color space of sRGB was used to test gamut-mapping algorithms, used to be integrated with tone-mapping module derived.

The role of internal duplication in the evolution of multi-domain proteins.

PubMed

Nacher, J C; Hayashida, M; Akutsu, T

2010-08-01

Many proteins consist of several structural domains. These multi-domain proteins have likely been generated by selective genome growth dynamics during evolution to perform new functions as well as to create structures that fold on a biologically feasible time scale. Domain units frequently evolved through a variety of genetic shuffling mechanisms. Here we examine the protein domain statistics of more than 1000 organisms including eukaryotic, archaeal and bacterial species. The analysis extends earlier findings on asymmetric statistical laws for proteome to a wider variety of species. While proteins are composed of a wide range of domains, displaying a power-law decay, the computation of domain families for each protein reveals an exponential distribution, characterizing a protein universe composed of a thin number of unique families. Structural studies in proteomics have shown that domain repeats, or internal duplicated domains, represent a small but significant fraction of genome. In spite of its importance, this observation has been largely overlooked until recently. We model the evolutionary dynamics of proteome and demonstrate that these distinct distributions are in fact rooted in an internal duplication mechanism. This process generates the contemporary protein structural domain universe, determines its reduced thickness, and tames its growth. These findings have important implications, ranging from protein interaction network modeling to evolutionary studies based on fundamental mechanisms governing genome expansion.

Rapid evolution of regulatory element libraries for tunable transcriptional and translational control of gene expression.

PubMed

Jin, Erqing; Wong, Lynn; Jiao, Yun; Engel, Jake; Holdridge, Benjamin; Xu, Peng

2017-12-01

Engineering cell factories for producing biofuels and pharmaceuticals has spurred great interests to develop rapid and efficient synthetic biology tools customized for modular pathway engineering. Along the way, combinatorial gene expression control through modification of regulatory element offered tremendous opportunity for fine-tuning gene expression and generating digital-like genetic circuits. In this report, we present an efficient evolutionary approach to build a range of regulatory control elements. The reported method allows for rapid construction of promoter, 5'UTR, terminator and trans -activating RNA libraries. Synthetic overlapping oligos with high portion of degenerate nucleotides flanking the regulatory element could be efficiently assembled to a vector expressing fluorescence reporter. This approach combines high mutation rate of the synthetic DNA with the high assembly efficiency of Gibson Mix. Our constructed library demonstrates broad range of transcriptional or translational gene expression dynamics. Specifically, both the promoter library and 5'UTR library exhibits gene expression dynamics spanning across three order of magnitude. The terminator library and trans -activating RNA library displays relatively narrowed gene expression pattern. The reported study provides a versatile toolbox for rapidly constructing a large family of prokaryotic regulatory elements. These libraries also facilitate the implementation of combinatorial pathway engineering principles and the engineering of more efficient microbial cell factory for various biomanufacturing applications.

Wafer-level vacuum packaged resonant micro-scanning mirrors for compact laser projection displays

NASA Astrophysics Data System (ADS)

Hofmann, Ulrich; Oldsen, Marten; Quenzer, Hans-Joachim; Janes, Joachim; Heller, Martin; Weiss, Manfred; Fakas, Georgios; Ratzmann, Lars; Marchetti, Eleonora; D'Ascoli, Francesco; Melani, Massimiliano; Bacciarelli, Luca; Volpi, Emilio; Battini, Francesco; Mostardini, Luca; Sechi, Francesco; De Marinis, Marco; Wagner, Bernd

2008-02-01

Scanning laser projection using resonant actuated MEMS scanning mirrors is expected to overcome the current limitation of small display size of mobile devices like cell phones, digital cameras and PDAs. Recent progress in the development of compact modulated RGB laser sources enables to set up very small laser projection systems that become attractive not only for consumer products but also for automotive applications like head-up and dash-board displays. Within the last years continuous progress was made in increasing MEMS scanner performance. However, only little is reported on how mass-produceability of these devices and stable functionality even under harsh environmental conditions can be guaranteed. Automotive application requires stable MEMS scanner operation over a wide temperature range from -40° to +85°Celsius. Therefore, hermetic packaging of electrostatically actuated MEMS scanning mirrors becomes essential to protect the sensitive device against particle contamination and condensing moisture. This paper reports on design, fabrication and test of a resonant actuated two-dimensional micro scanning mirror that is hermetically sealed on wafer level. With resonant frequencies of 30kHz and 1kHz, an achievable Theta-D-product of 13mm.deg and low dynamic deformation <20nm RMS it targets Lissajous projection with SVGA-resolution. Inevitable reflexes at the vacuum package surface can be seperated from the projection field by permanent inclination of the micromirror.

Measurement of luminance noise and chromaticity noise of LCDs with a colorimeter and a color camera

NASA Astrophysics Data System (ADS)

Roehrig, H.; Dallas, W. J.; Krupinski, E. A.; Redford, Gary R.

2007-09-01

This communication focuses on physical evaluation of image quality of displays for applications in medical imaging. In particular we were interested in luminance noise as well as chromaticity noise of LCDs. Luminance noise has been encountered in the study of monochrome LCDs for some time, but chromaticity noise is a new type of noise which has been encountered first when monochrome and color LCDs were compared in an ROC study. In this present study one color and one monochrome 3 M-pixel LCDs were studied. Both were DICOM calibrated with equal dynamic range. We used a Konica Minolta Chroma Meter CS-200 as well as a Foveon color camera to estimate luminance and chrominance variations of the displays. We also used a simulation experiment to estimate luminance noise. The measurements with the colorimeter were consistent. The measurements with the Foveon color camera were very preliminary as color cameras had never been used for image quality measurements. However they were extremely promising. The measurements with the colorimeter and the simulation results showed that the luminance and chromaticity noise of the color LCD were larger than that of the monochrome LCD. Under the condition that an adequate calibration method and image QA/QC program for color displays are available, we expect color LCDs may be ready for radiology in very near future.

Loss estimation and damage forecast using database provided

NASA Astrophysics Data System (ADS)

Pyrchenko, V.; Byrova, V.; Petrasov, A.

2009-04-01

There is a wide spectrum of development of natural hazards is observed in Russian territory. It the necessity of investigation of numerous events of dangerous natural processes, researches of mechanisms of their development and interaction with each other (synergetic amplification or new hazards emerging) with the purpose of the forecast of possible losses. Employees of Laboratory of the analysis of geological risk IEG RAS have created a database about displays of natural hazards in territory of Russia, which contains the information on 1310 cases of their display during 1991 - 2008. The wide range of the used sources has determined certain difficulties in creation of Database and has demanded to develop a special new technique of unification of the information received at different times. One of points of this technique is classification of negative consequences of display of the natural hazards, considering a death-roll, wounded mans, victims and direct economic damage. This Database has allowed to track dynamics of natural hazards and the emergency situations caused by them (ES) for the considered period, and also to define laws of their development in territory of Russia in time and space. It gives the chance to create theoretical, methodological and methodical bases of forecasting of possible losses with a certain degree of probability for territory of Russia and for its separate regions that guarantees in the future maintenance of adequate, operative and efficient pre-emptive decision-making.

Experimental Study of Slabbing and Rockburst Induced by True-Triaxial Unloading and Local Dynamic Disturbance

NASA Astrophysics Data System (ADS)

Du, Kun; Tao, Ming; Li, Xi-bing; Zhou, Jian

2016-09-01

Slabbing/spalling and rockburst are unconventional types of failure of hard rocks under conditions of unloading and various dynamic loads in environments with high and complex initial stresses. In this study, the failure behaviors of different rock types (granite, red sandstone, and cement mortar) were investigated using a novel testing system coupled to true-triaxial static loads and local dynamic disturbances. An acoustic emission system and a high-speed camera were used to record the real-time fracturing processes. The true-triaxial unloading test results indicate that slabbing occurred in the granite and sandstone, whereas the cement mortar underwent shear failure. Under local dynamically disturbed loading, none of the specimens displayed obvious fracturing at low-amplitude local dynamic loading; however, the degree of rock failure increased as the local dynamic loading amplitude increased. The cement mortar displayed no failure during testing, showing a considerable load-carrying capacity after testing. The sandstone underwent a relatively stable fracturing process, whereas violent rockbursts occurred in the granite specimen. The fracturing process does not appear to depend on the direction of local dynamic loading, and the acoustic emission count rate during rock fragmentation shows that similar crack evolution occurred under the two test scenarios (true-triaxial unloading and local dynamically disturbed loading).

OMV mission simulator

NASA Technical Reports Server (NTRS)

Cok, Keith E.

1989-01-01

The Orbital Maneuvering Vehicle (OMV) will be remotely piloted during rendezvous, docking, or proximity operations with target spacecraft from a ground control console (GCC). The real-time mission simulator and graphics being used to design a console pilot-machine interface are discussed. A real-time orbital dynamics simulator drives the visual displays. The dynamics simulator includes a J2 oblate earth gravity model and a generalized 1962 rotating atmospheric and drag model. The simulator also provides a variable-length communication delay to represent use of the Tracking and Data Relay Satellite System (TDRSS) and NASA Communications (NASCOM). Input parameter files determine the graphics display. This feature allows rapid prototyping since displays can be easily modified from pilot recommendations. A series of pilot reviews are being held to determine an effective pilot-machine interface. Pilots fly missions with nominal to 3-sigma dispersions in translational or rotational axes. Console dimensions, switch type and layout, hand controllers, and graphic interfaces are evaluated by the pilots and the GCC simulator is modified for subsequent runs. Initial results indicate a pilot preference for analog versus digital displays and for two 3-degree-of-freedom hand controllers.

Microtubule-based nanomaterials: Exploiting nature's dynamic biopolymers

DOE PAGES

Bachand, George D.; Stevens, Mark J.; Spoerke, Erik David

2015-04-09

For more than a decade now, biomolecular systems have served as an inspiration for the development of synthetic nanomaterials and systems that are capable of reproducing many of unique and emergent behaviors of living systems. In addition, one intriguing element of such systems may be found in a specialized class of proteins known as biomolecular motors that are capable of performing useful work across multiple length scales through the efficient conversion of chemical energy. Microtubule (MT) filaments may be considered within this context as their dynamic assembly and disassembly dissipate energy, and perform work within the cell. MTs are onemore » of three cytoskeletal filaments in eukaryotic cells, and play critical roles in a range of cellular processes including mitosis and vesicular trafficking. Based on their function, physical attributes, and unique dynamics, MTs also serve as a powerful archetype of a supramolecular filament that underlies and drives multiscale emergent behaviors. In this review, we briefly summarize recent efforts to generate hybrid and composite nanomaterials using MTs as biomolecular scaffolds, as well as computational and synthetic approaches to develop synthetic one-dimensional nanostructures that display the enviable attributes of the natural filaments.« less

Contrasting patterns of nutrient dynamics during different storm events in a semi-arid catchment of northern China.

PubMed

Du, Xinzhong; Li, Xuyong; Hao, Shaonan; Wang, Huiliang; Shen, Xiao

2014-01-01

Nutrient discharge during storm events is a critical pathway for nutrient export in semi-arid catchments. We investigated nutrient dynamics during three summer storms characterized by different rainfall magnitude in 2012 in a semi-arid catchment of northern China. The results showed that, in response to storm events, nutrient dynamics displayed big variation in temporal trends of nutrient concentration and in nutrient concentration-flow discharge relationships. Nutrient concentrations had broader fluctuations during an extreme storm than during lesser storms, whereas the concentration ranges of the a moderate storm were no broader than those of a smaller one. The different concentration fluctuations were caused by storm magnitude and intensity coupled with the antecedent rainfall amount and cumulative nutrients. Correlation coefficients between nutrient concentrations and flow discharge varied from positive to negative for the three different events. There were no consistent hysteresis effects for the three different events, and no hysteresis effects were observed for any of the variables during the moderate storm (E2). Our findings provide useful information for better understanding nutrient loss mechanisms during storm events in semi-arid areas of a monsoon climate region.

Hypervelocity Impact Test Fragment Modeling: Modifications to the Fragment Rotation Analysis and Lightcurve Code

NASA Technical Reports Server (NTRS)

Gouge, Michael F.

2011-01-01

Hypervelocity impact tests on test satellites are performed by members of the orbital debris scientific community in order to understand and typify the on-orbit collision breakup process. By analysis of these test satellite fragments, the fragment size and mass distributions are derived and incorporated into various orbital debris models. These same fragments are currently being put to new use using emerging technologies. Digital models of these fragments are created using a laser scanner. A group of computer programs referred to as the Fragment Rotation Analysis and Lightcurve code uses these digital representations in a multitude of ways that describe, measure, and model on-orbit fragments and fragment behavior. The Dynamic Rotation subroutine generates all of the possible reflected intensities from a scanned fragment as if it were observed to rotate dynamically while in orbit about the Earth. This calls an additional subroutine that graphically displays the intensities and the resulting frequency of those intensities as a range of solar phase angles in a Probability Density Function plot. This document reports the additions and modifications to the subset of the Fragment Rotation Analysis and Lightcurve concerned with the Dynamic Rotation and Probability Density Function plotting subroutines.

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

Busch, Albert; Kiel, Tilman; Heupel, Wolfgang-M.

Lamins, which form the nuclear lamina, not only constitute an important determinant of nuclear architecture, but additionally play essential roles in many nuclear functions. Mutations in A-type lamins cause a wide range of human genetic disorders (laminopathies). The importance of lamin A (LaA) in the spatial arrangement of nuclear pore complexes (NPCs) prompted us to study the role of LaA mutants in nuclear protein transport. Two mutants, causing prenatal skin disease restrictive dermopathy (RD) and the premature aging disease Hutchinson Gilford progeria syndrome, were used for expression in HeLa cells to investigate their impact on the subcellular localization of NPC-associatedmore » proteins and nuclear protein import. Furthermore, dynamics of the LaA mutants within the nuclear lamina were studied. We observed affected localization of NPC-associated proteins, diminished lamina dynamics for both LaA mutants and reduced nuclear import of representative cargo molecules. Intriguingly, both LaA mutants displayed similar effects on nuclear morphology and functions, despite their differences in disease severity. Reduced nuclear protein import was also seen in RD fibroblasts and impaired lamina dynamics for the nucleoporin Nup153. Our data thus represent the first study of a direct link between LaA mutant expression and reduced nuclear protein import.« less

Structural and Dynamical Properties of Alkaline Earth Metal Halides in Supercritical Water: Effect of Ion Size and Concentration.

PubMed

Keshri, Sonanki; Tembe, B L

2017-11-22

Constant temperature-constant pressure molecular dynamics simulations have been performed for aqueous alkaline earth metal chloride [M 2+ -Cl - (M = Mg, Ca, Sr, and Ba)] solutions over a wide range of concentrations (0.27-5.55 m) in supercritical (SC) and ambient conditions to investigate their structural and dynamical properties. A strong influence of the salt concentration is observed on the ion-ion pair correlation functions in both ambient and SC conditions. In SC conditions, significant clustering is observed in the 0.27 m solution, whereas the reverse situation is observed at room temperature and this is also supported by the residence times of the clusters. The concentration and ion size (cation size) seem to have opposite effects on the average number of hydrogen bonds. The simulation results show that the self-diffusion coefficients of water, cations, and the chloride ion increase with increasing temperature, whereas they decrease with increasing salt concentration. The cluster size distribution shows a strong density dependence in both ambient and SC conditions. In SC conditions, cluster sizes display a near-Gaussian distribution, whereas the distribution decays monotonically in ambient conditions.

Drop impact on liquid film: dynamics of interfacial gas layer

NASA Astrophysics Data System (ADS)

Tang, Xiaoyu; Saha, Abhishek; Law, Chung K.; Sun, Chao

2016-11-01

Drop impacting liquid film is commonly observed in many processes including inkjet printing and thermal sprays. Owing to the resistance from the interfacial gas layer trapped between the drop and film surface, impact may not always result in coalescence; and as such investigating the behavior of the interfacial gas layer is important to understand the transition between bouncing and merging outcomes. The gas layer is, however, not easily optically accessible due to its microscopic scale and curved interfaces. We report the measurement of this critical gas layer thickness between two liquid surfaces using high-speed color interferometry capable of measuring micron and submicron thicknesses. The complete gas layer dynamics for the bouncing cases can be divided into two stages: the approaching stage when the drop squeezes the gas layer at the beginning of the impact, and the rebounding stage when the drop retracts and rebounds from the liquid film. The approaching stage is found to be similar across wide range of conditions studied. However, for the rebounding stage, with increase of liquid film thickness, the evolution of gas layer changes dramatically, displaying a non-monotonic behavior. Such dynamics is analyzed in lights of various competing timescales.

Low-energy Structural Dynamics of Multiferroic Domain Walls in Hexagonal Rare-earth Manganites

NASA Astrophysics Data System (ADS)

Wu, Xiaoyu; Petralanda, Urko; Zheng, Lu; Ren, Yuan; Hu, Rongwei; Cheong, Sang-Wook; Artyukhin, Sergey; Lai, Keji

Multiferroic domain walls (DWs), the natural interfaces between domains with different order parameters, usually exhibit unconventional functionalities. For instance, recent discovery of the ferroelectric DW conduction highlights its extraordinary electronic structure that is absent in bulk domains. The structural dynamics of individual DWs in the microwave regime, however, have not been fully explored due to the lack of spatially resolved studies. Here, we report the broadband (106-1010 Hz) scanning impedance microscopy results on the interlocked anti-phase boundaries and ferroelectric DWs in hexagonal rare-earth manganites. Surprisingly, the effective conductivity of the (001) DWs displays a 106-fold increase from dc to GHz frequencies, while the effect is absent on surfaces with in-plane polarized domains. First-principles and model calculations indicate that the frequency range and selection rules are consistent with the periodic sliding of the DW around its equilibrium position. This DW acoustic-wave-like mode, which is associated with the synchronized oscillation of local polarization and apical oxygen atoms, is localized perpendicular to the DW but free to propagate along the DW plane. Our results break the ground to understand structural DW dynamics and exploit new interfacial phenomena for novel devices.

Pilot Preferences for Information Provided and Its Format for Status, Alerts, and Controls

NASA Technical Reports Server (NTRS)

Trujillo, Anna C.

2004-01-01

With the increased use of cathode ray tubes (CRTs) in flight decks and the computing power available, it is possible to combine status screens, alerts/procedures screens, and control screens onto a single display. This report presents the results of a survey designed to assess the perceived helpfulness and need of various pieces of information that could be included on status and control screens. The results from the survey indicate that operators want parameter ranges that change depending on the current aircraft configuration shown on bow-tie or dial displays. These displays should show the current value, normal range, alert type and range, and predictive information. Respondents wanted to see system relationships to one another for both component control and menu selection. When bringing up these various displays, this information should come up with a single button push. Finally, checklists should sense when a component has changed to the desired state.

Optimizing visual comfort for stereoscopic 3D display based on color-plus-depth signals.

PubMed

Shao, Feng; Jiang, Qiuping; Fu, Randi; Yu, Mei; Jiang, Gangyi

2016-05-30

Visual comfort is a long-facing problem in stereoscopic 3D (S3D) display. In this paper, targeting to produce S3D content based on color-plus-depth signals, a general framework for depth mapping to optimize visual comfort for S3D display is proposed. The main motivation of this work is to remap the depth range of color-plus-depth signals to a new depth range that is suitable to comfortable S3D display. Towards this end, we first remap the depth range globally based on the adjusted zero disparity plane, and then present a two-stage global and local depth optimization solution to solve the visual comfort problem. The remapped depth map is used to generate the S3D output. We demonstrate the power of our approach on perceptually uncomfortable and comfortable stereoscopic images.

Adaptive Controller Adaptation Time and Available Control Authority Effects on Piloting

NASA Technical Reports Server (NTRS)

Trujillo, Anna; Gregory, Irene

2013-01-01

Adaptive control is considered for highly uncertain, and potentially unpredictable, flight dynamics characteristic of adverse conditions. This experiment looked at how adaptive controller adaptation time to recover nominal aircraft dynamics affects pilots and how pilots want information about available control authority transmitted. Results indicate that an adaptive controller that takes three seconds to adapt helped pilots when looking at lateral and longitudinal errors. The controllability ratings improved with the adaptive controller, again the most for the three seconds adaptation time while workload decreased with the adaptive controller. The effects of the displays showing the percentage amount of available safe flight envelope used in the maneuver were dominated by the adaptation time. With the displays, the altitude error increased, controllability slightly decreased, and mental demand increased. Therefore, the displays did require some of the subjects resources but these negatives may be outweighed by pilots having more situation awareness of their aircraft.

Flight Simulator Visual-Display Delay Compensation

NASA Technical Reports Server (NTRS)

Crane, D. Francis

1981-01-01

A piloted aircraft can be viewed as a closed-loop man-machine control system. When a simulator pilot is performing a precision maneuver, a delay in the visual display of aircraft response to pilot-control input decreases the stability of the pilot-aircraft system. The less stable system is more difficult to control precisely. Pilot dynamic response and performance change as the pilot attempts to compensate for the decrease in system stability. The changes in pilot dynamic response and performance bias the simulation results by influencing the pilot's rating of the handling qualities of the simulated aircraft. The study reported here evaluated an approach to visual-display delay compensation. The objective of the compensation was to minimize delay-induced change in pilot performance and workload, The compensation was effective. Because the compensation design approach is based on well-established control-system design principles, prospects are favorable for successful application of the approach in other simulations.

Organic light emitting board for dynamic interactive display

PubMed Central

Kim, Eui Hyuk; Cho, Sung Hwan; Lee, Ju Han; Jeong, Beomjin; Kim, Richard Hahnkee; Yu, Seunggun; Lee, Tae-Woo; Shim, Wooyoung; Park, Cheolmin

2017-01-01

Interactive displays involve the interfacing of a stimuli-responsive sensor with a visual human-readable response. Here, we describe a polymeric electroluminescence-based stimuli-responsive display method that simultaneously detects external stimuli and visualizes the stimulant object. This organic light-emitting board is capable of both sensing and direct visualization of a variety of conductive information. Simultaneous sensing and visualization of the conductive substance is achieved when the conductive object is coupled with the light emissive material layer on application of alternating current. A variety of conductive materials can be detected regardless of their work functions, and thus information written by a conductive pen is clearly visualized, as is a human fingerprint with natural conductivity. Furthermore, we demonstrate that integration of the organic light-emitting board with a fluidic channel readily allows for dynamic monitoring of metallic liquid flow through the channel, which may be suitable for biological detection and imaging applications. PMID:28406151

Organic light emitting board for dynamic interactive display

NASA Astrophysics Data System (ADS)

Kim, Eui Hyuk; Cho, Sung Hwan; Lee, Ju Han; Jeong, Beomjin; Kim, Richard Hahnkee; Yu, Seunggun; Lee, Tae-Woo; Shim, Wooyoung; Park, Cheolmin

2017-04-01

Interactive displays involve the interfacing of a stimuli-responsive sensor with a visual human-readable response. Here, we describe a polymeric electroluminescence-based stimuli-responsive display method that simultaneously detects external stimuli and visualizes the stimulant object. This organic light-emitting board is capable of both sensing and direct visualization of a variety of conductive information. Simultaneous sensing and visualization of the conductive substance is achieved when the conductive object is coupled with the light emissive material layer on application of alternating current. A variety of conductive materials can be detected regardless of their work functions, and thus information written by a conductive pen is clearly visualized, as is a human fingerprint with natural conductivity. Furthermore, we demonstrate that integration of the organic light-emitting board with a fluidic channel readily allows for dynamic monitoring of metallic liquid flow through the channel, which may be suitable for biological detection and imaging applications.

Bursting and critical layer frequencies in minimal turbulent dynamics and connections to exact coherent states

NASA Astrophysics Data System (ADS)

Park, Jae Sung; Shekar, Ashwin; Graham, Michael D.

2018-01-01

The dynamics of the turbulent near-wall region is known to be dominated by coherent structures. These near-wall coherent structures are observed to burst in a very intermittent fashion, exporting turbulent kinetic energy to the rest of the flow. In addition, they are closely related to invariant solutions known as exact coherent states (ECS), some of which display nonlinear critical layer dynamics (motions that are highly localized around the surface on which the streamwise velocity matches the wave speed of ECS). The present work aims to investigate temporal coherence in minimal channel flow relevant to turbulent bursting and critical layer dynamics and its connection to the instability of ECS. It is seen that the minimal channel turbulence displays frequencies very close to those displayed by an ECS family recently identified in the channel flow geometry. The frequencies of these ECS are determined by critical layer structures and thus might be described as "critical layer frequencies." While the bursting frequency is predominant near the wall, the ECS frequencies (critical layer frequencies) become predominant over the bursting frequency at larger distances from the wall, and increasingly so as Reynolds number increases. Turbulent bursts are classified into strong and relatively weak classes with respect to an intermittent approach to a lower branch ECS. This temporally intermittent approach is closely related to an intermittent low drag event, called hibernating turbulence, found in minimal and large domains. The relationship between the strong burst and the instability of the lower branch ECS is further discussed in state space. The state-space dynamics of strong bursts is very similar to that of the unstable manifolds of the lower branch ECS. In particular, strong bursting processes are always preceded by hibernation events. This precursor dynamics to strong turbulence may aid in development of more effective control schemes by a way of anticipating dynamics such as intermittent hibernating dynamics.

A flexible flight display research system using a ground-based interactive graphics terminal

NASA Technical Reports Server (NTRS)

Hatfield, J. J.; Elkins, H. C.; Batson, V. M.; Poole, W. L.

1975-01-01

Requirements and research areas for the air transportation system of the 1980 to 1990's were reviewed briefly to establish the need for a flexible flight display generation research tool. Specific display capabilities required by aeronautical researchers are listed and a conceptual system for providing these capabilities is described. The conceptual system uses a ground-based interactive graphics terminal driven by real-time radar and telemetry data to generate dynamic, experimental flight displays. These displays are scan converted to television format, processed, and transmitted to the cockpits of evaluation aircraft. The attendant advantages of a Flight Display Research System (FDRS) designed to employ this concept are presented. The detailed implementation of an FDRS is described. The basic characteristics of the interactive graphics terminal and supporting display electronic subsystems are presented and the resulting system capability is summarized. Finally, the system status and utilization are reviewed.

Eleven fetal echocardiographic planes using 4-dimensional ultrasound with spatio-temporal image correlation (STIC): a logical approach to fetal heart volume analysis.

PubMed

Jantarasaengaram, Surasak; Vairojanavong, Kittipong

2010-09-15

Theoretically, a cross-sectional image of any cardiac planes can be obtained from a STIC fetal heart volume dataset. We described a method to display 11 fetal echocardiographic planes from STIC volumes. Fetal heart volume datasets were acquired by transverse acquisition from 200 normal fetuses at 15 to 40 weeks of gestation. Analysis of the volume datasets using the described technique to display 11 echocardiographic planes in the multiplanar display mode were performed offline. Volume datasets from 18 fetuses were excluded due to poor image resolution. The mean visualization rates for all echocardiographic planes at 15-17, 18-22, 23-27, 28-32 and 33-40 weeks of gestation fetuses were 85.6% (range 45.2-96.8%, N = 31), 92.9% (range 64.0-100%, N = 64), 93.4% (range 51.4-100%, N = 37), 88.7%(range 54.5-100%, N = 33) and 81.8% (range 23.5-100%, N = 17) respectively. Overall, the applied technique can favorably display the pertinent echocardiographic planes. Description of the presented method provides a logical approach to explore the fetal heart volumes.

Experimental Studies of the Effect of Intent Information on Cockpit Traffic Displays

NASA Technical Reports Server (NTRS)

Barhydt, Richard; Hansman, R. John

1997-01-01

Intent information provides knowledge of another aircraft's current and future trajectory states. Prototype traffic displays were designed for four different levels of intent: Position, Rate, Commanded State, and FMS (Flight Management System)-Path. The current TCAS (traffic collision avoidance systems) Display, which shows altitude rate in addition to current position and altitude, was used as a baseline and represents the lowest level of intent. The Rate, Commanded State, and FMS-Path Displays show increasing levels of intent information using TCAS-like symbology in addition to incorporating a conflict probe and profile view display. An initial experiment was run on the MIT (Massachusetts Institute of Technology) Part Task Flight Simulator in which eight airline pilots flew five traffic scenarios with each of the four displays. Results show that pilots had fewer separation violations and maneuvered earlier with the three intent displays. Separation violations were reduced when pilots maneuvered earlier. A second experiment was run to compare performance between displaying intent information directly and incorporating it into a conflict probe. A different set of eight airline pilots flew four traffic scenarios with the TCAS and Commanded State Displays with and without the conflict probe. Conflict probes with two minute and long range look-ahead times were tested. Displaying conflict bands or showing intent information directly both led to fewer separation violations and earlier avoidance maneuvers than the base TCAS Display. Performance was similar between the two minute and long range look-ahead conflict probes. Pilots preferred all intent displays over the TCAS Display.

Tooth display and lip position during spontaneous and posed smiling in adults.

PubMed

Van Der Geld, Pieter; Oosterveld, Paul; Berge, Stefaan J; Kuijpers-Jagtman, Anne M

2008-08-01

To analyze differences in tooth display, lip-line height, and smile width between the posed smiling record, traditionally produced for orthodontic diagnosis, and the spontaneous (Duchenne) smile of joy. The faces of 122 male participants were each filmed during spontaneous and posed smiling. Spontaneous smiles were elicited through the participants watching a comical movie. Maxillary and mandibular lip-line heights, tooth display, and smile width were measured using a digital videographic method for smile analysis. Paired sample t-tests were used to compare measurements of posed and spontaneous smiling. Maxillary lip-line heights during spontaneous smiling were significantly higher than during posed smiling. Compared to spontaneous smiling, tooth display in the (pre)molar area during posed smiling decreased by up to 30%, along with a significant reduction of smile width. During posed smiling, also mandibular lip-line heights changed and the teeth were more covered by the lower lip than during spontaneous smiling. Reduced lip-line heights, tooth display, and smile width on a posed smiling record can have implications for the diagnostics of lip-line height, smile arc, buccal corridors, and plane of occlusion. Spontaneous smiling records next to posed smiling records are therefore recommended for diagnostic purposes. Because of the dynamic nature of spontaneous smiling, it is proposed to switch to dynamic video recording of the smile.

Advanced Pathway Guidance Evaluations on a Synthetic Vision Head-Up Display

NASA Technical Reports Server (NTRS)

Kramer, Lynda J.; Prinzel, Lawrence J., III; Arthur, Jarvis J., III; Bailey, Randall E.

2005-01-01

NASA's Synthetic Vision Systems (SVS) project is developing technologies with practical applications to potentially eliminate low visibility conditions as a causal factor to civil aircraft accidents while replicating the operational benefits of clear day flight operations, regardless of the actual outside visibility condition. A major thrust of the SVS project involves the development/demonstration of affordable, certifiable display configurations that provide intuitive out-the-window terrain and obstacle information with advanced guidance for commercial and business aircraft. This experiment evaluated the influence of different pathway and guidance display concepts upon pilot situation awareness (SA), mental workload, and flight path tracking performance for Synthetic Vision display concepts using a Head-Up Display (HUD). Two pathway formats (dynamic and minimal tunnel presentations) were evaluated against a baseline condition (no tunnel) during simulated instrument meteorological conditions approaches to Reno-Tahoe International airport. Two guidance cues (tadpole, follow-me aircraft) were also evaluated to assess their influence. Results indicated that the presence of a tunnel on an SVS HUD had no effect on flight path performance but that it did have significant effects on pilot SA and mental workload. The dynamic tunnel concept with the follow-me aircraft guidance symbol produced the lowest workload and provided the highest SA among the tunnel concepts evaluated.

Automated detection of solar eruptions

NASA Astrophysics Data System (ADS)

Hurlburt, N.

2015-12-01

Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections (CMEs). Identifying and characterizing these motions are essential to advancing our understanding of the drivers of space weather. Both automated and visual identifications are currently used in identifying Coronal Mass Ejections. To date, eruptions near the solar surface, which may be precursors to CMEs, have been identified primarily by visual inspection. Here we report on Eruption Patrol (EP): a software module that is designed to automatically identify eruptions from data collected by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO/AIA). We describe the method underlying the module and compare its results to previous identifications found in the Heliophysics Event Knowledgebase. EP identifies eruptions events that are consistent with those found by human annotations, but in a significantly more consistent and quantitative manner. Eruptions are found to be distributed within 15 Mm of the solar surface. They possess peak speeds ranging from 4 to 100 km/s and display a power-law probability distribution over that range. These characteristics are consistent with previous observations of prominences.

Characterizing the effects of droplines on target acquisition performance on a 3-D perspective display

NASA Technical Reports Server (NTRS)

Liao, Min-Ju; Johnson, Walter W.

2004-01-01

The present study investigated the effects of droplines on target acquisition performance on a 3-D perspective display in which participants were required to move a cursor into a target cube as quickly as possible. Participants' performance and coordination strategies were characterized using both Fitts' law and acquisition patterns of the 3 viewer-centered target display dimensions (azimuth, elevation, and range). Participants' movement trajectories were recorded and used to determine movement times for acquisitions of the entire target and of each of its display dimensions. The goodness of fit of the data to a modified Fitts function varied widely among participants, and the presence of droplines did not have observable impacts on the goodness of fit. However, droplines helped participants navigate via straighter paths and particularly benefited range dimension acquisition. A general preference for visually overlapping the target with the cursor prior to capturing the target was found. Potential applications of this research include the design of interactive 3-D perspective displays in which fast and accurate selection and manipulation of content residing at multiple ranges may be a challenge.

Functional coordination of muscles underlying changes in behavioural dynamics.

PubMed

Vernooij, Carlijn A; Rao, Guillaume; Perdikis, Dionysios; Huys, Raoul; Jirsa, Viktor K; Temprado, Jean-Jacques

2016-06-10

The dynamical systems approach addresses Bernstein's degrees of freedom problem by assuming that the neuro-musculo-skeletal system transiently assembles and dismantles its components into functional units (or synergies) to meet task demands. Strikingly, little is known from a dynamical point of view about the functioning of the muscular sub-system in this process. To investigate the interaction between the dynamical organisation at muscular and behavioural levels, we searched for specific signatures of a phase transition in muscular coordination when a transition is displayed at the behavioural level. Our results provide evidence that, during Fitts' task when behaviour switches to a different dynamical regime, muscular activation displays typical signatures of a phase transition; a reorganisation in muscular coordination patterns accompanied by a peak in the variability of muscle activation. This suggests that consistent changes occur in coordination processes across the different levels of description (i.e., behaviour and muscles). Specifically, in Fitts' task, target size acts as a control parameter that induces a destabilisation and a reorganisation of coordination patterns at different levels of the neuro-musculo-skeletal system.

Polarization-tuned Dynamic Color Filters Incorporating a Dielectric-loaded Aluminum Nanowire Array

PubMed Central

Raj Shrestha, Vivek; Lee, Sang-Shin; Kim, Eun-Soo; Choi, Duk-Yong

2015-01-01

Nanostructured spectral filters enabling dynamic color-tuning are saliently attractive for implementing ultra-compact color displays and imaging devices. Realization of polarization-induced dynamic color-tuning via one-dimensional periodic nanostructures is highly challenging due to the absence of plasmonic resonances for transverse-electric polarization. Here we demonstrate highly efficient dynamic subtractive color filters incorporating a dielectric-loaded aluminum nanowire array, providing a continuum of customized color according to the incident polarization. Dynamic color filtering was realized relying on selective suppression in transmission spectra via plasmonic resonance at a metal-dielectric interface and guided-mode resonance for a metal-clad dielectric waveguide, each occurring at their characteristic wavelengths for transverse-magnetic and electric polarizations, respectively. A broad palette of colors, including cyan, magenta, and yellow, has been attained with high transmission beyond 80%, by tailoring the period of the nanowire array and the incident polarization. Thanks to low cost, high durability, and mass producibility of the aluminum adopted for the proposed devices, they are anticipated to be diversely applied to color displays, holographic imaging, information encoding, and anti-counterfeiting. PMID:26211625

Dynamic Training Elements in a Circuit Theory Course to Implement a Self-Directed Learning Process

ERIC Educational Resources Information Center

Krouk, B. I.; Zhuravleva, O. B.

2009-01-01

This paper reports on the implementation of a self-directed learning process in a circuit theory course, incorporating dynamic training elements which were designed on the basis of a cybernetic model of cognitive process management. These elements are centrally linked in a dynamic learning frame, created on the monitor screen, which displays the…

The use of head-mounted display eyeglasses for teaching surgical skills: A prospective randomised study.

PubMed

Peden, Robert G; Mercer, Rachel; Tatham, Andrew J

2016-10-01

To investigate whether 'surgeon's eye view' videos provided via head-mounted displays can improve skill acquisition and satisfaction in basic surgical training compared with conventional wet-lab teaching. A prospective randomised study of 14 medical students with no prior suturing experience, randomised to 3 groups: 1) conventional teaching; 2) head-mounted display-assisted teaching and 3) head-mounted display self-learning. All were instructed in interrupted suturing followed by 15 minutes' practice. Head-mounted displays provided a 'surgeon's eye view' video demonstrating the technique, available during practice. Subsequently students undertook a practical assessment, where suturing was videoed and graded by masked assessors using a 10-point surgical skill score (1 = very poor technique, 10 = very good technique). Students completed a questionnaire assessing confidence and satisfaction. Suturing ability after teaching was similar between groups (P = 0.229, Kruskal-Wallis test). Median surgical skill scores were 7.5 (range 6-10), 6 (range 3-8) and 7 (range 1-7) following head-mounted display-assisted teaching, conventional teaching, and head-mounted display self-learning respectively. There was good agreement between graders regarding surgical skill scores (rho.c = 0.599, r = 0.603), and no difference in number of sutures placed between groups (P = 0.120). The head-mounted display-assisted teaching group reported greater enjoyment than those attending conventional teaching (P = 0.033). Head-mounted display self-learning was regarded as least useful (7.4 vs 9.0 for conventional teaching, P = 0.021), but more enjoyable than conventional teaching (9.6 vs 8.0, P = 0.050). Teaching augmented with head-mounted displays was significantly more enjoyable than conventional teaching. Students undertaking self-directed learning using head-mounted displays with pre-recorded videos had comparable skill acquisition to those attending traditional wet-lab tutorials. Copyright © 2016 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

The USL NASA PC R and D interactive presentation development system

NASA Technical Reports Server (NTRS)

Dominick, Wayne D. (Editor); Moreau, Dennis R.

1984-01-01

The Interactive Presentation Development System (IPFS) is a highly interactive system for creating, editing, and displaying video presentation sequences, e.g., for developing and presenting displays of instructional material similiar to overhead transparency or slide presentations. However, since this system is PC-based, users (instructors) can step through sequences forward or backward, focusing attention to areas of the display with special cursor pointers. Additionally, screen displays may be dynamically modified during the presentation to show assignments or to answer questions, much like a traditional blackboard. This system is now implemented at the University of Southwestern Louisiana for use within the piloting phases of the NASA contract work.

New-type planar field emission display with superaligned carbon nanotube yarn emitter.

PubMed

Liu, Peng; Wei, Yang; Liu, Kai; Liu, Liang; Jiang, Kaili; Fan, Shoushan

2012-05-09

With the superaligned carbon nanotube yarn as emitter, we have fabricated a 16 × 16 pixel field emission display prototype by adopting screen printing and laser cutting technologies. A planar diode field emission structure has been adopted. A very sharp carbon nanotube yarn tip emitter can be formed by laser cutting. Low voltage phosphor was coated on the anode electrodes also by screen printing. With a specially designed circuit, we have demonstrated the dynamic character display with the field emission display prototype. The emitter material and fabrication technologies in this paper are both easy to scale up to large areas.

Influence of hydroclimatic variations on solute concentration dynamics in nested subtropical catchments with heterogeneous landscapes.

PubMed

Piazza, Gustavo Antonio; Dupas, Rémi; Gascuel-Odoux, Chantal; Grimaldi, Catherine; Pinheiro, Adilson; Kaufmann, Vander

2018-04-20

Despite global efforts to monitor water quality in catchments worldwide, tropical and subtropical zones still lack data to study the influence of human activities and climate variations on solute dynamics. In this study, we monitored ten solutes every two weeks for six years (2010-2015) in three nested catchments (2 to30 km 2 ), which contained heterogeneous landscapes composed of forests and agricultural land, and one small neighboring forested catchment (0.4 km 2 ). Data analysis revealed that i) rainfall, discharge and solute concentrations displayed no clear seasonal patterns, unlike many catchments of the temperate zone; ii) solute concentrations in the agricultural area were higher than those in the forested area, but both areas displayed similar temporal patterns due to a common hydroclimatic driver; iii) all four catchments displayed a chemostatic export regime for most of the solutes, similar to catchments of the temperate zone; and iv) a positive correlation was observed between anion concentrations and ENSO (El Niño-Southern Oscillation) index. ENSO appeared to influence both hydroclimatic and anion dynamics in these subtropical catchments. Copyright © 2018 Elsevier B.V. All rights reserved.

Improving Ecological Forecasting: Data Assimilation Enhances the Ecological Forecast Horizon of a Complex Food Web

NASA Astrophysics Data System (ADS)

Massoud, E. C.; Huisman, J.; Benincà, E.; Bouten, W.; Vrugt, J. A.

2017-12-01

Species abundances in ecological communities can display chaotic non-equilibrium dynamics. A characteristic feature of chaotic systems is that long-term prediction of the system's trajectory is fundamentally impossible. How then should we make predictions for complex multi-species communities? We explore data assimilation (DA) with the Ensemble Kalman Filter (EnKF) to fuse a two-predator-two-prey model with abundance data from a long term experiment of a plankton community which displays chaotic dynamics. The results show that DA improves substantially the predictability and ecological forecast horizon of complex community dynamics. In addition, we show that DA helps provide guidance on measurement design, for instance on defining the frequency of observations. The study presented here is highly innovative, because DA methods at the current stage are almost unknown in ecology.

Similarity of vegetation dynamics during interglacial periods

PubMed Central

Cheddadi, Rachid; de Beaulieu, Jacques-Louis; Jouzel, Jean; Andrieu-Ponel, Valérie; Laurent, Jeanne-Marine; Reille, Maurice; Raynaud, Dominique; Bar-Hen, Avner

2005-01-01

The Velay sequence (France) provides a unique, continuous, palynological record spanning the last four climatic cycles. A pollen-based reconstruction of temperature and precipitation displays marked climatic cycles. An analysis of the climate and vegetation changes during the interglacial periods reveals comparable features and identical major vegetation successions. Although Marine Isotope Stage (MIS) 11.3 and the Holocene had similar earth precessional variations, their correspondence in terms of vegetation dynamics is low. MIS 9.5, 7.5, and especially 5.5 display closer correlation to the Holocene than MIS 11.3. Ecological factors, such as the distribution and composition of glacial refugia or postglacial migration patterns, may explain these discrepancies. Comparison of ecosystem dynamics during the past five interglacials suggests that vegetation development in the current interglacial has no analogue from the past 500,000 years. PMID:16162676

Reducing Visual Discomfort with HMDs Using Dynamic Depth of Field.

PubMed

Carnegie, Kieran; Rhee, Taehyun

2015-01-01

Although head-mounted displays (HMDs) are ideal devices for personal viewing of immersive stereoscopic content, exposure to VR applications on them results in significant discomfort for the majority of people, with symptoms including eye fatigue, headaches, nausea, and sweating. A conflict between accommodation and vergence depth cues on stereoscopic displays is a significant cause of visual discomfort. This article describes the results of an evaluation used to judge the effectiveness of dynamic depth-of-field (DoF) blur in an effort to reduce discomfort caused by exposure to stereoscopic content on HMDs. Using a commercial game engine implementation, study participants report a reduction of visual discomfort on a simulator sickness questionnaire when DoF blurring is enabled. The study participants reported a decrease in symptom severity caused by HMD exposure, indicating that dynamic DoF can effectively reduce visual discomfort.

Field emitter displays for future avionics applications

NASA Astrophysics Data System (ADS)

Jones, Susan K.; Jones, Gary W.; Zimmerman, Steven M.; Blazejewski, Edward R.

1995-06-01

Field emitter array-based display technology offers CRT-like characteristics in a thin flat-panel display with many potential applications for vehicle-mounted, crew workstation, and helmet-mounted displays, as well as many other military and commercial applications. In addition to thinness, high brightness, wide viewing angle, wide temperature range, and low weight, field emitter array displays also offer potential advantages such as row-at-a-time matrix addressability and the ability to be segmented.

Progress of OLED devices with high efficiency at high luminance

NASA Astrophysics Data System (ADS)

Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

2014-03-01

Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

Monkey vocal tracts are speech-ready.

PubMed

Fitch, W Tecumseh; de Boer, Bart; Mathur, Neil; Ghazanfar, Asif A

2016-12-01

For four decades, the inability of nonhuman primates to produce human speech sounds has been claimed to stem from limitations in their vocal tract anatomy, a conclusion based on plaster casts made from the vocal tract of a monkey cadaver. We used x-ray videos to quantify vocal tract dynamics in living macaques during vocalization, facial displays, and feeding. We demonstrate that the macaque vocal tract could easily produce an adequate range of speech sounds to support spoken language, showing that previous techniques based on postmortem samples drastically underestimated primate vocal capabilities. Our findings imply that the evolution of human speech capabilities required neural changes rather than modifications of vocal anatomy. Macaques have a speech-ready vocal tract but lack a speech-ready brain to control it.

Evolution of pairwise entanglement in a coupled n-body system

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

Pineda, Carlos; Centro de Ciencias Fisicas, University of Mexico; Seligman, Thomas H.

2006-01-15

We study the exact evolution of two noninteracting qubits, initially in a Bell state, in the presence of an environment, modeled by a kicked Ising spin chain. Dynamics of this model range from integrable to chaotic and we can handle numerics for a large number of qubits. We find that the entanglement (as measured by concurrence) of the two qubits has a close relation to the purity of the pair, and closely follows an analytic relation derived for Werner states. As a collateral result we find that an integrable environment causes quadratic decay of concurrence as well as of purity,more » while a chaotic environment causes linear decay. Both quantities display recurrences in an integrable environment.« less

Nonlinear Optical Image Processing with Bacteriorhodopsin Films

NASA Technical Reports Server (NTRS)

Downie, John D.; Deiss, Ron (Technical Monitor)

1994-01-01

The transmission properties of some bacteriorhodopsin film spatial light modulators are uniquely suited to allow nonlinear optical image processing operations to be applied to images with multiplicative noise characteristics. A logarithmic amplitude transmission feature of the film permits the conversion of multiplicative noise to additive noise, which may then be linearly filtered out in the Fourier plane of the transformed image. The bacteriorhodopsin film displays the logarithmic amplitude response for write beam intensities spanning a dynamic range greater than 2.0 orders of magnitude. We present experimental results demonstrating the principle and capability for several different image and noise situations, including deterministic noise and speckle. Using the bacteriorhodopsin film, we successfully filter out image noise from the transformed image that cannot be removed from the original image.

Localization of soft modes at the depinning transition

NASA Astrophysics Data System (ADS)

Cao, Xiangyu; Bouzat, Sebastian; Kolton, Alejandro B.; Rosso, Alberto

2018-02-01

We characterize the soft modes of the dynamical matrix at the depinning transition, and compare the matrix with the properties of the Anderson model (and long-range generalizations). The density of states at the edge of the spectrum displays a universal linear tail, different from the Lifshitz tails. The eigenvectors are instead very similar in the two matrix ensembles. We focus on the ground state (soft mode), which represents the epicenter of avalanche instabilities. We expect it to be localized in all finite dimensions, and make a clear connection between its localization length and the Larkin length of the depinning model. In the fully connected model, we show that the weak-strong pinning transition coincides with a peculiar localization transition of the ground state.

A study of image quality for radar image processing. [synthetic aperture radar imagery

NASA Technical Reports Server (NTRS)

King, R. W.; Kaupp, V. H.; Waite, W. P.; Macdonald, H. C.

1982-01-01

Methods developed for image quality metrics are reviewed with focus on basic interpretation or recognition elements including: tone or color; shape; pattern; size; shadow; texture; site; association or context; and resolution. Seven metrics are believed to show promise as a way of characterizing the quality of an image: (1) the dynamic range of intensities in the displayed image; (2) the system signal-to-noise ratio; (3) the system spatial bandwidth or bandpass; (4) the system resolution or acutance; (5) the normalized-mean-square-error as a measure of geometric fidelity; (6) the perceptual mean square error; and (7) the radar threshold quality factor. Selective levels of degradation are being applied to simulated synthetic radar images to test the validity of these metrics.

Adventures in Modern Time Series Analysis: From the Sun to the Crab Nebula and Beyond

NASA Technical Reports Server (NTRS)

Scargle, Jeffrey

2014-01-01

With the generation of long, precise, and finely sampled time series the Age of Digital Astronomy is uncovering and elucidating energetic dynamical processes throughout the Universe. Fulfilling these opportunities requires data effective analysis techniques rapidly and automatically implementing advanced concepts. The Time Series Explorer, under development in collaboration with Tom Loredo, provides tools ranging from simple but optimal histograms to time and frequency domain analysis for arbitrary data modes with any time sampling. Much of this development owes its existence to Joe Bredekamp and the encouragement he provided over several decades. Sample results for solar chromospheric activity, gamma-ray activity in the Crab Nebula, active galactic nuclei and gamma-ray bursts will be displayed.

Increased collection efficiency of LIFI high intensity electrodeless light source

NASA Astrophysics Data System (ADS)

Hafidi, Abdeslam; DeVincentis, Marc; Duelli, Markus; Gilliard, Richard

2008-02-01

Recently, RF driven electrodeless high intensity light sources have been implemented successfully in the projection display systems for HDTV and videowall applications. This paper presents advances made in the RF waveguide and electric field concentrator structures with the purpose of reducing effective arc size and increasing light collection. In addition, new optical designs are described that further improve system efficiency. The results of this work demonstrate that projection system light throughput is increased relative to previous implementations and performance is optimized for home theater and other front projector applications that maintain multi-year lifetime without re-lamping, complete spectral range, fast start times and high levels of dynamic contrast due to dimming flexibility in the light source system.

Toward the light field display: autostereoscopic rendering via a cluster of projectors.

PubMed

Yang, Ruigang; Huang, Xinyu; Li, Sifang; Jaynes, Christopher

2008-01-01

Ultimately, a display device should be capable of reproducing the visual effects observed in reality. In this paper we introduce an autostereoscopic display that uses a scalable array of digital light projectors and a projection screen augmented with microlenses to simulate a light field for a given three-dimensional scene. Physical objects emit or reflect light in all directions to create a light field that can be approximated by the light field display. The display can simultaneously provide many viewers from different viewpoints a stereoscopic effect without head tracking or special viewing glasses. This work focuses on two important technical problems related to the light field display; calibration and rendering. We present a solution to automatically calibrate the light field display using a camera and introduce two efficient algorithms to render the special multi-view images by exploiting their spatial coherence. The effectiveness of our approach is demonstrated with a four-projector prototype that can display dynamic imagery with full parallax.

Impact of Martensite Spatial Distribution on Quasi-Static and Dynamic Deformation Behavior of Dual-Phase Steel

NASA Astrophysics Data System (ADS)

Singh, Manpreet; Das, Anindya; Venugopalan, T.; Mukherjee, Krishnendu; Walunj, Mahesh; Nanda, Tarun; Kumar, B. Ravi

2017-12-01

The effects of microstructure parameters of dual-phase steels on tensile high strain dynamic deformation characteristic were examined in this study. Cold-rolled steel sheets were annealed using three different annealing process parameters to obtain three different dual-phase microstructures of varied ferrite and martensite phase fraction. The volume fraction of martensite obtained in two of the steels was near identical ( 19 pct) with a subtle difference in its spatial distribution. In the first microstructure variant, martensite was mostly found to be situated at ferrite grain boundaries and in the second variant, in addition to at grain boundaries, in-grain martensite was also observed. The third microstructure was very different from the above two with respect to martensite volume fraction ( 67 pct) and its morphology. In this case, martensite packets were surrounded by a three-dimensional ferrite network giving an appearance of core and shell type microstructure. All the three steels were tensile deformed at strain rates ranging from 2.7 × 10-4 (quasi-static) to 650 s-1 (dynamic range). Field-emission scanning electron microscope was used to characterize the starting as well as post-tensile deformed microstructures. Dual-phase steel consisting of small martensite volume fraction ( 19 pct), irrespective of its spatial distribution, demonstrated high strain rate sensitivity and on the other hand, steel with large martensite volume fraction ( 67 pct) displayed a very little strain rate sensitivity. Interestingly, total elongation was found to increase with increasing strain rate in the dynamic regime for steel with core-shell type of microstructure containing large martensite volume fraction. The observed enhancement in plasticity in dynamic regime was attributed to adiabatic heating of specimen. To understand the evolving damage mechanism, the fracture surface and the vicinity of fracture ends were studied in all the three dual-phase steels.

Impact of Martensite Spatial Distribution on Quasi-Static and Dynamic Deformation Behavior of Dual-Phase Steel

NASA Astrophysics Data System (ADS)

Singh, Manpreet; Das, Anindya; Venugopalan, T.; Mukherjee, Krishnendu; Walunj, Mahesh; Nanda, Tarun; Kumar, B. Ravi

2018-02-01

The effects of microstructure parameters of dual-phase steels on tensile high strain dynamic deformation characteristic were examined in this study. Cold-rolled steel sheets were annealed using three different annealing process parameters to obtain three different dual-phase microstructures of varied ferrite and martensite phase fraction. The volume fraction of martensite obtained in two of the steels was near identical ( 19 pct) with a subtle difference in its spatial distribution. In the first microstructure variant, martensite was mostly found to be situated at ferrite grain boundaries and in the second variant, in addition to at grain boundaries, in-grain martensite was also observed. The third microstructure was very different from the above two with respect to martensite volume fraction ( 67 pct) and its morphology. In this case, martensite packets were surrounded by a three-dimensional ferrite network giving an appearance of core and shell type microstructure. All the three steels were tensile deformed at strain rates ranging from 2.7 × 10-4 (quasi-static) to 650 s-1 (dynamic range). Field-emission scanning electron microscope was used to characterize the starting as well as post-tensile deformed microstructures. Dual-phase steel consisting of small martensite volume fraction ( 19 pct), irrespective of its spatial distribution, demonstrated high strain rate sensitivity and on the other hand, steel with large martensite volume fraction ( 67 pct) displayed a very little strain rate sensitivity. Interestingly, total elongation was found to increase with increasing strain rate in the dynamic regime for steel with core-shell type of microstructure containing large martensite volume fraction. The observed enhancement in plasticity in dynamic regime was attributed to adiabatic heating of specimen. To understand the evolving damage mechanism, the fracture surface and the vicinity of fracture ends were studied in all the three dual-phase steels.

Dynamic measures of RSA predict distress and regulation in toddlers.

PubMed

Brooker, Rebecca J; Buss, Kristin A

2010-05-01

In this study, we examined a new method for quantifying individual variability using dynamic measures of respiratory sinus arrhythmia (RSA). This method incorporated temporal variation into the measurement of RSA and provided information beyond that offered by more traditional quantifications such as difference scores. Dynamic and static measures of change in RSA were tested in relation to displays of emotion and affective behaviors during a fear-eliciting episode in a sample of 88 typically developing and high-fear toddlers during a laboratory visit at age 24 months. Dynamic measures of RSA contributed information that was unique from traditionally employed, static change scores in predicting high-fear toddlers' displays of shyness during a fear-eliciting episode. In contrast, RSA change scores offered information related to boldness in nonhigh-fear children. In addition, several associations included estimates of nonlinear change in RSA. Implications for the study of individual differences in RSA and relations with emotion and emotion regulation are discussed.

Effect of dynamic temperature storage in retail display case on the quality and microbiota of packaged fresh-cut leafy greens

USDA-ARS?s Scientific Manuscript database

Commercial refrigeration equipment is projected to rise 5.2% annually to meet the consumer demand for fresh-cut produce items. The highly variable temperature conditions associated with storage of fresh-cuts in commercial open-refrigerated display cases dramatically affects the shelf-life and qualit...

Flexible Animation Computer Program

NASA Technical Reports Server (NTRS)

Stallcup, Scott S.

1990-01-01

FLEXAN (Flexible Animation), computer program animating structural dynamics on Evans and Sutherland PS300-series graphics workstation with VAX/VMS host computer. Typical application is animation of spacecraft undergoing structural stresses caused by thermal and vibrational effects. Displays distortions in shape of spacecraft. Program displays single natural mode of vibration, mode history, or any general deformation of flexible structure. Written in FORTRAN 77.

Dynamics of comb-of-comb-network polymers in random layered flows

NASA Astrophysics Data System (ADS)

Katyal, Divya; Kant, Rama

2016-12-01

We analyze the dynamics of comb-of-comb-network polymers in the presence of external random flows. The dynamics of such structures is evaluated through relevant physical quantities, viz., average square displacement (ASD) and the velocity autocorrelation function (VACF). We focus on comparing the dynamics of the comb-of-comb network with the linear polymer. The present work displays an anomalous diffusive behavior of this flexible network in the random layered flows. The effect of the polymer topology on the dynamics is analyzed by varying the number of generations and branch lengths in these networks. In addition, we investigate the influence of external flow on the dynamics by varying flow parameters, like the flow exponent α and flow strength Wα. Our analysis highlights two anomalous power-law regimes, viz., subdiffusive (intermediate-time polymer stretching and flow-induced diffusion) and superdiffusive (long-time flow-induced diffusion). The anomalous long-time dynamics is governed by the temporal exponent ν of ASD, viz., ν =2 -α /2 . Compared to a linear polymer, the comb-of-comb network shows a shorter crossover time (from the subdiffusive to superdiffusive regime) but a reduced magnitude of ASD. Our theory displays an anomalous VACF in the random layered flows that scales as t-α /2. We show that the network with greater total mass moves faster.

Deciphering the Dynamic Interaction Profile of an Intrinsically Disordered Protein by NMR Exchange Spectroscopy.

PubMed

Delaforge, Elise; Kragelj, Jaka; Tengo, Laura; Palencia, Andrés; Milles, Sigrid; Bouvignies, Guillaume; Salvi, Nicola; Blackledge, Martin; Jensen, Malene Ringkjøbing

2018-01-24

Intrinsically disordered proteins (IDPs) display a large number of interaction modes including folding-upon-binding, binding without major structural transitions, or binding through highly dynamic, so-called fuzzy, complexes. The vast majority of experimental information about IDP binding modes have been inferred from crystal structures of proteins in complex with short peptides of IDPs. However, crystal structures provide a mainly static view of the complexes and do not give information about the conformational dynamics experienced by the IDP in the bound state. Knowledge of the dynamics of IDP complexes is of fundamental importance to understand how IDPs engage in highly specific interactions without concomitantly high binding affinity. Here, we combine rotating-frame R 1ρ , Carr-Purcell-Meiboom Gill relaxation dispersion as well as chemical exchange saturation transfer to decipher the dynamic interaction profile of an IDP in complex with its partner. We apply the approach to the dynamic signaling complex formed between the mitogen-activated protein kinase (MAPK) p38α and the intrinsically disordered regulatory domain of the MAPK kinase MKK4. Our study demonstrates that MKK4 employs a subtle combination of interaction modes in order to bind to p38α, leading to a complex displaying significantly different dynamics across the bound regions.

Multiple dynamics in a single predator-prey system: experimental effects of food quality.

PubMed Central

Nelson, W A; McCauley, E; Wrona, F J

2001-01-01

Recent work with the freshwater zooplankton Daphnia has suggested that the quality of its algal prey can have a significant effect on its demographic rates and life-history patterns. Predator-prey theory linking food quantity and food quality predicts that a single system should be able to display two distinct patterns of population dynamics. One pattern is predicted to have high herbivore and low algal biomass dynamics (high HBD), whereas the other is predicted to have low herbivore and high algal biomass dynamics (low HBD). Despite these predictions and the stoichiometric evidence that many phytoplankton communities may have poor access to food of quality, there have been few tests of whether a dynamic predator-prey system can display both of these distinct patterns. Here we report, to the authors' knowledge, the first evidence for two dynamical patterns, as predicted by theory, in a single predator-prey system. We show that the high HBD is a result of food quantity effects and that the low HBD is a result of food quality effects, which are maintained by phosphorus limitation in the predator. These results provide an important link between the known effects of nutrient limitation in herbivores and the significance of prey quality in predator-prey population dynamics in natural zooplankton communities. PMID:11410147

Providing Web Interfaces to the NSF EarthScope USArray Transportable Array

NASA Astrophysics Data System (ADS)

Vernon, Frank; Newman, Robert; Lindquist, Kent

2010-05-01

Since April 2004 the EarthScope USArray seismic network has grown to over 850 broadband stations that stream multi-channel data in near real-time to the Array Network Facility in San Diego. Providing secure, yet open, access to real-time and archived data for a broad range of audiences is best served by a series of platform agnostic low-latency web-based applications. We present a framework of tools that mediate between the world wide web and Boulder Real Time Technologies Antelope Environmental Monitoring System data acquisition and archival software. These tools provide comprehensive information to audiences ranging from network operators and geoscience researchers, to funding agencies and the general public. This ranges from network-wide to station-specific metadata, state-of-health metrics, event detection rates, archival data and dynamic report generation over a station's two year life span. Leveraging open source web-site development frameworks for both the server side (Perl, Python and PHP) and client-side (Flickr, Google Maps/Earth and jQuery) facilitates the development of a robust extensible architecture that can be tailored on a per-user basis, with rapid prototyping and development that adheres to web-standards. Typical seismic data warehouses allow online users to query and download data collected from regional networks, without the scientist directly visually assessing data coverage and/or quality. Using a suite of web-based protocols, we have recently developed an online seismic waveform interface that directly queries and displays data from a relational database through a web-browser. Using the Python interface to Datascope and the Python-based Twisted network package on the server side, and the jQuery Javascript framework on the client side to send and receive asynchronous waveform queries, we display broadband seismic data using the HTML Canvas element that is globally accessible by anyone using a modern web-browser. We are currently creating additional interface tools to create a rich-client interface for accessing and displaying seismic data that can be deployed to any system running the Antelope Real Time System. The software is freely available from the Antelope contributed code Git repository (http://www.antelopeusersgroup.org).

Vertical navigation displays : pilot performance and workload during simulated constant-angle-of-descent GPS approaches

DOT National Transportation Integrated Search

2000-03-26

This study compared the effect of alternative graphic or : numeric cockpit display formats on the tactical aspects of : vertical navigation (VNAV). Display formats included: : a) a moving map with altitude range arc, b) the same : format, supplemente...

An integrated pipeline to create and experience compelling scenarios in virtual reality

NASA Astrophysics Data System (ADS)

Springer, Jan P.; Neumann, Carsten; Reiners, Dirk; Cruz-Neira, Carolina

2011-03-01

One of the main barriers to create and use compelling scenarios in virtual reality is the complexity and time-consuming efforts for modeling, element integration, and the software development to properly display and interact with the content in the available systems. Still today, most virtual reality applications are tedious to create and they are hard-wired to the specific display and interaction system available to the developers when creating the application. Furthermore, it is not possible to alter the content or the dynamics of the content once the application has been created. We present our research on designing a software pipeline that enables the creation of compelling scenarios with a fair degree of visual and interaction complexity in a semi-automated way. Specifically, we are targeting drivable urban scenarios, ranging from large cities to sparsely populated rural areas that incorporate both static components (e. g., houses, trees) and dynamic components (e. g., people, vehicles) as well as events, such as explosions or ambient noise. Our pipeline has four basic components. First, an environment designer, where users sketch the overall layout of the scenario, and an automated method constructs the 3D environment from the information in the sketch. Second, a scenario editor used for authoring the complete scenario, incorporate the dynamic elements and events, fine tune the automatically generated environment, define the execution conditions of the scenario, and set up any data gathering that may be necessary during the execution of the scenario. Third, a run-time environment for different virtual-reality systems provides users with the interactive experience as designed with the designer and the editor. And fourth, a bi-directional monitoring system that allows for capturing and modification of information from the virtual environment. One of the interesting capabilities of our pipeline is that scenarios can be built and modified on-the-fly as they are being presented in the virtual-reality systems. Users can quickly prototype the basic scene using the designer and the editor on a control workstation. More elements can then be introduced into the scene from both the editor and the virtual-reality display. In this manner, users are able to gradually increase the complexity of the scenario with immediate feedback. The main use of this pipeline is the rapid development of scenarios for human-factors studies. However, it is applicable in a much more general context.

Self-organization in leaky threshold systems: The influence of near-mean field dynamics and its implications for earthquakes, neurobiology, and forecasting

PubMed Central

Rundle, J. B.; Tiampo, K. F.; Klein, W.; Sá Martins, J. S.

2002-01-01

Threshold systems are known to be some of the most important nonlinear self-organizing systems in nature, including networks of earthquake faults, neural networks, superconductors and semiconductors, and the World Wide Web, as well as political, social, and ecological systems. All of these systems have dynamics that are strongly correlated in space and time, and all typically display a multiplicity of spatial and temporal scales. Here we discuss the physics of self-organization in earthquake threshold systems at two distinct scales: (i) The “microscopic” laboratory scale, in which consideration of results from simulations leads to dynamical equations that can be used to derive the results obtained from sliding friction experiments, and (ii) the “macroscopic” earthquake fault-system scale, in which the physics of strongly correlated earthquake fault systems can be understood by using time-dependent state vectors defined in a Hilbert space of eigenstates, similar in many respects to the mathematics of quantum mechanics. In all of these systems, long-range interactions induce the existence of locally ergodic dynamics. The existence of dissipative effects leads to the appearance of a “leaky threshold” dynamics, equivalent to a new scaling field that controls the size of nucleation events relative to the size of background fluctuations. At the macroscopic earthquake fault-system scale, these ideas show considerable promise as a means of forecasting future earthquake activity. PMID:11875204

Biodynamic Doppler imaging of subcellular motion inside 3D living tissue culture and biopsies (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nolte, David D.

2016-03-01

Biodynamic imaging is an emerging 3D optical imaging technology that probes up to 1 mm deep inside three-dimensional living tissue using short-coherence dynamic light scattering to measure the intracellular motions of cells inside their natural microenvironments. Biodynamic imaging is label-free and non-invasive. The information content of biodynamic imaging is captured through tissue dynamics spectroscopy that displays the changes in the Doppler signatures from intracellular constituents in response to applied compounds. The affected dynamic intracellular mechanisms include organelle transport, membrane undulations, cytoskeletal restructuring, strain at cellular adhesions, cytokinesis, mitosis, exo- and endo-cytosis among others. The development of 3D high-content assays such as biodynamic profiling can become a critical new tool for assessing efficacy of drugs and the suitability of specific types of tissue growth for drug discovery and development. The use of biodynamic profiling to predict clinical outcome of living biopsies to cancer therapeutics can be developed into a phenotypic companion diagnostic, as well as a new tool for therapy selection in personalized medicine. This invited talk will present an overview of the optical, physical and physiological processes involved in biodynamic imaging. Several different biodynamic imaging modalities include motility contrast imaging (MCI), tissue-dynamics spectroscopy (TDS) and tissue-dynamics imaging (TDI). A wide range of potential applications will be described that include process monitoring for 3D tissue culture, drug discovery and development, cancer therapy selection, embryo assessment for in-vitro fertilization and artificial reproductive technologies, among others.

Deciphering Dynamical Patterns of Growth Processes

ERIC Educational Resources Information Center

Kolakowska, A.

2009-01-01

Large systems of statistical physics often display properties that are independent of particulars that characterize their microscopic components. Universal dynamical patterns are manifested by the presence of scaling laws, which provides a common insight into governing physics of processes as vastly diverse as, e.g., growth of geological…

Thermoreversible Gels Composed of Colloidal Silica Rods with Short-Range Attractions

DOE PAGES

Murphy, Ryan P.; Hong, Kunlun; Wagner, Norman J.

2016-07-28

Dynamic arrest transitions of colloidal suspensions containing non-spherical particles are of interest for the design and processing of various particle technologies. To better understand the effects of particle shape anisotropy and attraction strength on gel and glass formation, we present a colloidal model system of octadecyl-coated silica rods, termed as adhesive hard rods (AHR), which enables control of rod aspect ratio and temperature-dependent interactions. The aspect ratios of silica rods were controlled by varying the initial TEOS concentration following the work of Kuijk et al. (J. Am. Chem. Soc., 2011, 133, 2346–2349) and temperature-dependent attractions were introduced by coating themore » calcined silica rods with an octadecyl-brush and suspending in tetradecane. The rod length and aspect ratio were found to increase with TEOS concentration as expected, while other properties such as the rod diameter, coating coverage, density, and surface roughness were nearly independent of the aspect ratio. Ultra-small angle X-ray scattering measurements revealed temperature-dependent attractions between octadecyl-coated silica rods in tetradecane, as characterized by a low-q upturn in the scattered intensity upon thermal quenching. Lastly, the rheology of a concentrated AHR suspension in tetradecane demonstrated thermoreversible gelation behavior, displaying a nearly 5 orders of magnitude change in the dynamic moduli as the temperature was cycled between 15 and 40 °C. We find the adhesive hard rod model system serves as a tunable platform to explore the combined influence of particle shape anisotropy and attraction strength on the dynamic arrest transitions in colloidal suspensions with thermoreversible, short-range attractions.« less

Current Status Of Ergonomic Standards

NASA Astrophysics Data System (ADS)

Lynch, Gene

1984-05-01

The last five years have seen the development and adoption of new kinds of standards for the display industry. This standardization activity deals with the complex human computer interface. Here the concerns involve health, safety, productivity, and operator well-being. The standards attempt to specify the "proper" use of visual display units. There is a wide range of implications for the display industry - as manufacturers of displays, as employers, and as users of visual display units. In this paper we examine the development of these standards, their impact on the display industry and implications for the future.

Liquid crystal dynamic flow control by bidirectional alignment surface

NASA Astrophysics Data System (ADS)

Li, Y. W.; Lee, C. Y.; Kwok, H. S.

2009-02-01

We investigate the behavior of liquid crystal dynamic flow in a cell with a bidirectional alignment (BDA) surface. Numerical simulations show that with a BDA surface having a pitch comparable to the cell gap d, the liquid crystal dynamic flow direction can be controlled by the driving voltage. Such an effect can be applied to bistable twisted nematic displays without the need for anchoring breaking.

Probing the structural and dynamical properties of liquid water with models including non-local electron correlation

NASA Astrophysics Data System (ADS)

Del Ben, Mauro; Hutter, Jürg; VandeVondele, Joost

2015-08-01

Water is a ubiquitous liquid that displays a wide range of anomalous properties and has a delicate structure that challenges experiment and simulation alike. The various intermolecular interactions that play an important role, such as repulsion, polarization, hydrogen bonding, and van der Waals interactions, are often difficult to reproduce faithfully in atomistic models. Here, electronic structure theories including all these interactions at equal footing, which requires the inclusion of non-local electron correlation, are used to describe structure and dynamics of bulk liquid water. Isobaric-isothermal (NpT) ensemble simulations based on the Random Phase Approximation (RPA) yield excellent density (0.994 g/ml) and fair radial distribution functions, while various other density functional approximations produce scattered results (0.8-1.2 g/ml). Molecular dynamics simulation in the microcanonical (NVE) ensemble based on Møller-Plesset perturbation theory (MP2) yields dynamical properties in the condensed phase, namely, the infrared spectrum and diffusion constant. At the MP2 and RPA levels of theory, ice is correctly predicted to float on water, resolving one of the anomalies as resulting from a delicate balance between van der Waals and hydrogen bonding interactions. For several properties, obtaining quantitative agreement with experiment requires correction for nuclear quantum effects (NQEs), highlighting their importance, for structure, dynamics, and electronic properties. A computed NQE shift of 0.6 eV for the band gap and absorption spectrum illustrates the latter. Giving access to both structure and dynamics of condensed phase systems, non-local electron correlation will increasingly be used to study systems where weak interactions are of paramount importance.

On The Ubiquity of Nonstationary Fluvial Suspended Sediment Dynamics: A Call for Long Term Monitoring and Dynamical Sediment Management Strategies

NASA Astrophysics Data System (ADS)

Gray, A. B.

2017-12-01

Watersheds with sufficient monitoring data have been predominantly found to display nonstationary suspended sediment dynamics, whereby the relationship between suspended sediment concentration and discharge changes over time. Despite the importance of suspended sediment as a keystone of geophysical and biochemical processes, and as a primary mediator of water quality, stationary behavior remains largely assumed in the context of these applications. This study presents an investigation into the time dependent behavior of small mountainous rivers draining the coastal ranges of the western continental US over interannual to interdecadal time scales. Of the 250+ small coastal (drainage area < 2x104 km2) watersheds in this region, only 23 have discharge associated suspended sediment concentration time series with base periods of 10 years or more. Event to interdecadal scale nonstationary suspended sediment dynamics were identified throughout these systems. Temporal patterns of non-stationary behavior provided some evidence for spatial coherence, which may be related to synoptic hydro-metrological patterns and regional scale changes in land use patterns. However, the results also highlight the complex, integrative nature of watershed scale fluvial suspended sediment dynamics. This underscores the need for in-depth, forensic approaches for initial processes identification, which require long term, high resolution monitoring efforts in order to adequately inform management. The societal implications of nonstationary sediment dynamics and their controls were further explored through the case of California, USA, where over 150 impairment listings have resulted in more than 50 sediment TMDLs, only 3 of which are flux based - none of which account for non-stationary behavior.

Experimental Characterization of Stress- and Strain-Dependent Stiffness in Grouted Rock Masses.

PubMed

Kim, Ji-Won; Chong, Song-Hun; Cho, Gye-Chun

2018-03-29

Grouting of fractured rock mass prior to excavation results in grout-filled discontinuities that govern the deformation characteristics of a site. The influence of joint characteristics on the properties of grouted rocks is important in assessing the effects of grouting on jointed rock mass. However, grouting remains a predominantly empirical practice and the effects of grouting on rock joint behavior and material properties have yet to be accurately assessed. Granular materials, including jointed rocks, typically display nonlinear strain-dependent responses that can be characterized by the shear modulus degradation curve. In this study, the effects of grouting on the strain-dependent shear stiffness of jointed rock mass were investigated at the small-strain (below 10 -5 ) and mid-strain (10 -5 to 10 -3 ) ranges using the quasi-static resonant column test and rock mass dynamic test devices. The effects of curing time, axial stress, initial joint roughness, and grouted joint thickness were examined. The results show that (1) grouting of rock joints leads to decreased stress sensitivity and increased small-strain shear stiffness for all tested samples; (2) the grouted rock samples display similar modulus degradation characteristics as the applied grout material; (3) the initial joint roughness determines the stress-dependent behaviors and general stiffness range of the jointed and grouted rocks, but the strain-dependent behaviors are dependent on the properties of the grout material; (4) increased grouted joint thickness results in larger contribution of the grout properties in the overall grouted rock mass.

Experimental Characterization of Stress- and Strain-Dependent Stiffness in Grouted Rock Masses

PubMed Central

Cho, Gye-Chun

2018-01-01

Grouting of fractured rock mass prior to excavation results in grout-filled discontinuities that govern the deformation characteristics of a site. The influence of joint characteristics on the properties of grouted rocks is important in assessing the effects of grouting on jointed rock mass. However, grouting remains a predominantly empirical practice and the effects of grouting on rock joint behavior and material properties have yet to be accurately assessed. Granular materials, including jointed rocks, typically display nonlinear strain-dependent responses that can be characterized by the shear modulus degradation curve. In this study, the effects of grouting on the strain-dependent shear stiffness of jointed rock mass were investigated at the small-strain (below 10−5) and mid-strain (10−5 to 10−3) ranges using the quasi-static resonant column test and rock mass dynamic test devices. The effects of curing time, axial stress, initial joint roughness, and grouted joint thickness were examined. The results show that (1) grouting of rock joints leads to decreased stress sensitivity and increased small-strain shear stiffness for all tested samples; (2) the grouted rock samples display similar modulus degradation characteristics as the applied grout material; (3) the initial joint roughness determines the stress-dependent behaviors and general stiffness range of the jointed and grouted rocks, but the strain-dependent behaviors are dependent on the properties of the grout material; (4) increased grouted joint thickness results in larger contribution of the grout properties in the overall grouted rock mass. PMID:29596371

Novel changes in discoidal high density lipoprotein morphology: a molecular dynamics study.

PubMed

Catte, Andrea; Patterson, James C; Jones, Martin K; Jerome, W Gray; Bashtovyy, Denys; Su, Zhengchang; Gu, Feifei; Chen, Jianguo; Aliste, Marcela P; Harvey, Stephen C; Li, Ling; Weinstein, Gilbert; Segrest, Jere P

2006-06-15

ApoA-I is a uniquely flexible lipid-scavenging protein capable of incorporating phospholipids into stable particles. Here we report molecular dynamics simulations on a series of progressively smaller discoidal high density lipoprotein particles produced by incremental removal of palmitoyloleoylphosphatidylcholine via four different pathways. The starting model contained 160 palmitoyloleoylphosphatidylcholines and a belt of two antiparallel amphipathic helical lipid-associating domains of apolipoprotein (apo) A-I. The results are particularly compelling. After a few nanoseconds of molecular dynamics simulation, independent of the starting particle and method of size reduction, all simulated double belts of the four lipidated apoA-I particles have helical domains that impressively approximate the x-ray crystal structure of lipid-free apoA-I, particularly between residues 88 and 186. These results provide atomic resolution models for two of the particles produced by in vitro reconstitution of nascent high density lipoprotein particles. These particles, measuring 95 angstroms and 78 angstroms by nondenaturing gradient gel electrophoresis, correspond in composition and in size/shape (by negative stain electron microscopy) to the simulated particles with molar ratios of 100:2 and 50:2, respectively. The lipids of the 100:2 particle family form minimal surfaces at their monolayer-monolayer interface, whereas the 50:2 particle family displays a lipid pocket capable of binding a dynamic range of phospholipid molecules.

Novel Changes in Discoidal High Density Lipoprotein Morphology: A Molecular Dynamics Study

PubMed Central

Catte, Andrea; Patterson, James C.; Jones, Martin K.; Jerome, W. Gray; Bashtovyy, Denys; Su, Zhengchang; Gu, Feifei; Chen, Jianguo; Aliste, Marcela P.; Harvey, Stephen C.; Li, Ling; Weinstein, Gilbert; Segrest, Jere P.

2006-01-01

ApoA-I is a uniquely flexible lipid-scavenging protein capable of incorporating phospholipids into stable particles. Here we report molecular dynamics simulations on a series of progressively smaller discoidal high density lipoprotein particles produced by incremental removal of palmitoyloleoylphosphatidylcholine via four different pathways. The starting model contained 160 palmitoyloleoylphosphatidylcholines and a belt of two antiparallel amphipathic helical lipid-associating domains of apolipoprotein (apo) A-I. The results are particularly compelling. After a few nanoseconds of molecular dynamics simulation, independent of the starting particle and method of size reduction, all simulated double belts of the four lipidated apoA-I particles have helical domains that impressively approximate the x-ray crystal structure of lipid-free apoA-I, particularly between residues 88 and 186. These results provide atomic resolution models for two of the particles produced by in vitro reconstitution of nascent high density lipoprotein particles. These particles, measuring 95 Å and 78 Å by nondenaturing gradient gel electrophoresis, correspond in composition and in size/shape (by negative stain electron microscopy) to the simulated particles with molar ratios of 100:2 and 50:2, respectively. The lipids of the 100:2 particle family form minimal surfaces at their monolayer-monolayer interface, whereas the 50:2 particle family displays a lipid pocket capable of binding a dynamic range of phospholipid molecules. PMID:16581834

Spiking and bursting patterns of fractional-order Izhikevich model

NASA Astrophysics Data System (ADS)

Teka, Wondimu W.; Upadhyay, Ranjit Kumar; Mondal, Argha

2018-03-01

Bursting and spiking oscillations play major roles in processing and transmitting information in the brain through cortical neurons that respond differently to the same signal. These oscillations display complex dynamics that might be produced by using neuronal models and varying many model parameters. Recent studies have shown that models with fractional order can produce several types of history-dependent neuronal activities without the adjustment of several parameters. We studied the fractional-order Izhikevich model and analyzed different kinds of oscillations that emerge from the fractional dynamics. The model produces a wide range of neuronal spike responses, including regular spiking, fast spiking, intrinsic bursting, mixed mode oscillations, regular bursting and chattering, by adjusting only the fractional order. Both the active and silent phase of the burst increase when the fractional-order model further deviates from the classical model. For smaller fractional order, the model produces memory dependent spiking activity after the pulse signal turned off. This special spiking activity and other properties of the fractional-order model are caused by the memory trace that emerges from the fractional-order dynamics and integrates all the past activities of the neuron. On the network level, the response of the neuronal network shifts from random to scale-free spiking. Our results suggest that the complex dynamics of spiking and bursting can be the result of the long-term dependence and interaction of intracellular and extracellular ionic currents.

Transitions from trees to cycles in adaptive flow networks

NASA Astrophysics Data System (ADS)

Martens, Erik A.; Klemm, Konstantin

2017-11-01

Transport networks are crucial to the functioning of natural and technological systems. Nature features transport networks that are adaptive over a vast range of parameters, thus providing an impressive level of robustness in supply. Theoretical and experimental studies have found that real-world transport networks exhibit both tree-like motifs and cycles. When the network is subject to load fluctuations, the presence of cyclic motifs may help to reduce flow fluctuations and, thus, render supply in the network more robust. While previous studies considered network topology via optimization principles, here, we take a dynamical systems approach and study a simple model of a flow network with dynamically adapting weights (conductances). We assume a spatially non-uniform distribution of rapidly fluctuating loads in the sinks and investigate what network configurations are dynamically stable. The network converges to a spatially non-uniform stable configuration composed of both cyclic and tree-like structures. Cyclic structures emerge locally in a transcritical bifurcation as the amplitude of the load fluctuations is increased. The resulting adaptive dynamics thus partitions the network into two distinct regions with cyclic and tree-like structures. The location of the boundary between these two regions is determined by the amplitude of the fluctuations. These findings may explain why natural transport networks display cyclic structures in the micro-vascular regions near terminal nodes, but tree-like features in the regions with larger veins.

Drying paint: from micro-scale dynamics to mechanical instabilities

NASA Astrophysics Data System (ADS)

Goehring, Lucas; Li, Joaquim; Kiatkirakajorn, Pree-Cha

2017-04-01

Charged colloidal dispersions make up the basis of a broad range of industrial and commercial products, from paints to coatings and additives in cosmetics. During drying, an initially liquid dispersion of such particles is slowly concentrated into a solid, displaying a range of mechanical instabilities in response to highly variable internal pressures. Here we summarize the current appreciation of this process by pairing an advection-diffusion model of particle motion with a Poisson-Boltzmann cell model of inter-particle interactions, to predict the concentration gradients in a drying colloidal film. We then test these predictions with osmotic compression experiments on colloidal silica, and small-angle X-ray scattering experiments on silica dispersions drying in Hele-Shaw cells. Finally, we use the details of the microscopic physics at play in these dispersions to explore how two macroscopic mechanical instabilities-shear-banding and fracture-can be controlled. This article is part of the themed issue 'Patterning through instabilities in complex media: theory and applications.'

Mammalian energetics. Instantaneous energetics of puma kills reveal advantage of felid sneak attacks.

PubMed

Williams, Terrie M; Wolfe, Lisa; Davis, Tracy; Kendall, Traci; Richter, Beau; Wang, Yiwei; Bryce, Caleb; Elkaim, Gabriel Hugh; Wilmers, Christopher C

2014-10-03

Pumas (Puma concolor) live in diverse, often rugged, complex habitats. The energy they expend for hunting must account for this complexity but is difficult to measure for this and other large, cryptic carnivores. We developed and deployed a physiological SMART (species movement, acceleration, and radio tracking) collar that used accelerometry to continuously monitor energetics, movements, and behavior of free-ranging pumas. This felid species displayed marked individuality in predatory activities, ranging from low-cost sit-and-wait behaviors to constant movements with energetic costs averaging 2.3 times those predicted for running mammals. Pumas reduce these costs by remaining cryptic and precisely matching maximum pouncing force (overall dynamic body acceleration = 5.3 to 16.1g) to prey size. Such instantaneous energetics help to explain why most felids stalk and pounce, and their analysis represents a powerful approach for accurately forecasting resource demands required for survival by large, mobile predators. Copyright © 2014, American Association for the Advancement of Science.

Femtosecond Photoelectron Imaging of Dissociating and Autoionizing States in Oxygen

NASA Astrophysics Data System (ADS)

Plunkett, Alexander; Sandhu, Arvinder

2017-04-01

Time-resolved photoelectron spectra from molecular oxygen have been recorded with high energy and time resolution using a velocity map imaging (VMI) spectrometer. High harmonics were used to prepare neutral Rydberg states converging to the c4Σu- ionic state. These states display both autoionization and predissociation. A femtosecond laser pulse centered at 780 nm was used to probe the system, ionizing both the excited molecular states and the predissociated neutral atomic fragments. Electrons were collected in the 0-3 eV range using a VMI spectrometer and their spectra were reconstructed using a Fast Onion-peeling algorithm. By looking at IR modification to the electron spectrum, new features are observed which could originate from long-range columbic interactions or previously unobserved molecular decay channels. Ongoing studies extend this technique to other systems exhibiting non-adiabatic dynamics. This work was supported by the U. S. Army Research Laboratory and the U. S. Army Research Office under Grant No. W911NF-14-1-0383.

The virtual brain: 30 years of video-game play and cognitive abilities.

PubMed

Latham, Andrew J; Patston, Lucy L M; Tippett, Lynette J

2013-09-13

Forty years have passed since video-games were first made widely available to the public and subsequently playing games has become a favorite past-time for many. Players continuously engage with dynamic visual displays with success contingent on the time-pressured deployment, and flexible allocation, of attention as well as precise bimanual movements. Evidence to date suggests that both brief and extensive exposure to video-game play can result in a broad range of enhancements to various cognitive faculties that generalize beyond the original context. Despite promise, video-game research is host to a number of methodological issues that require addressing before progress can be made in this area. Here an effort is made to consolidate the past 30 years of literature examining the effects of video-game play on cognitive faculties and, more recently, neural systems. Future work is required to identify the mechanism that allows the act of video-game play to generate such a broad range of generalized enhancements.

The virtual brain: 30 years of video-game play and cognitive abilities

PubMed Central

Latham, Andrew J.; Patston, Lucy L. M.; Tippett, Lynette J.

2013-01-01

Forty years have passed since video-games were first made widely available to the public and subsequently playing games has become a favorite past-time for many. Players continuously engage with dynamic visual displays with success contingent on the time-pressured deployment, and flexible allocation, of attention as well as precise bimanual movements. Evidence to date suggests that both brief and extensive exposure to video-game play can result in a broad range of enhancements to various cognitive faculties that generalize beyond the original context. Despite promise, video-game research is host to a number of methodological issues that require addressing before progress can be made in this area. Here an effort is made to consolidate the past 30 years of literature examining the effects of video-game play on cognitive faculties and, more recently, neural systems. Future work is required to identify the mechanism that allows the act of video-game play to generate such a broad range of generalized enhancements. PMID:24062712

Sequential dynamics of culturally moderated facial expressions of emotion.

PubMed

Matsumoto, David; Willingham, Bob; Olide, Andres

2009-10-01

There is consensus that when emotions are aroused, the displays of those emotions are either universal or culture-specific. We investigated the idea that an individual's emotional displays in a given context can be both universal and culturally variable, as they change over time. We examined the emotional displays of Olympic athletes across time, classified their expressive styles, and tested the association between those styles and a number of characteristics associated with the countries the athletes represented. Athletes from relatively urban, individualistic cultures expressed their emotions more, whereas athletes from less urban, collectivistic cultures masked their emotions more. These culturally influenced expressions occurred within a few seconds after initial, immediate, and universal emotional displays. Thus, universal and culture-specific emotional displays can unfold across time in an individual in a single context.

Improvement of Head-Up Display Standards. Volume 5. Head Up Display ILS (Instrument Landing System) Accuracy Flight Tests.

DTIC Science & Technology

1987-09-01

amber system. The front canopy of the NT-33A is cov- ered with an amber plastic sheet; when the front seat pilot low- ers his blue visor, the...tigation of the effect of head-up display symbol dynamic response caracteristics on flying qualities; Task B was an investigation of symbol accuracy...An amber vinyl plastic sheet covered the in- side front half of the NT-33 canopy. Blue snap-on visors were pi ovided to the evaluation pilots. The

Evaluating the Effects of Dimensionality in Advanced Avionic Display Concepts for Synthetic Vision Systems

NASA Technical Reports Server (NTRS)

Alexander, Amy L.; Prinzel, Lawrence J., III; Wickens, Christopher D.; Kramer, Lynda J.; Arthur, Jarvis J.; Bailey, Randall E.

2007-01-01

Synthetic vision systems provide an in-cockpit view of terrain and other hazards via a computer-generated display representation. Two experiments examined several display concepts for synthetic vision and evaluated how such displays modulate pilot performance. Experiment 1 (24 general aviation pilots) compared three navigational display (ND) concepts: 2D coplanar, 3D, and split-screen. Experiment 2 (12 commercial airline pilots) evaluated baseline 'blue sky/brown ground' or synthetic vision-enabled primary flight displays (PFDs) and three ND concepts: 2D coplanar with and without synthetic vision and a dynamic multi-mode rotatable exocentric format. In general, the results pointed to an overall advantage for a split-screen format, whether it be stand-alone (Experiment 1) or available via rotatable viewpoints (Experiment 2). Furthermore, Experiment 2 revealed benefits associated with utilizing synthetic vision in both the PFD and ND representations and the value of combined ego- and exocentric presentations.

Distance correction system for localization based on linear regression and smoothing in ambient intelligence display.

PubMed

Kim, Dae-Hee; Choi, Jae-Hun; Lim, Myung-Eun; Park, Soo-Jun

2008-01-01

This paper suggests the method of correcting distance between an ambient intelligence display and a user based on linear regression and smoothing method, by which distance information of a user who approaches to the display can he accurately output even in an unanticipated condition using a passive infrared VIR) sensor and an ultrasonic device. The developed system consists of an ambient intelligence display and an ultrasonic transmitter, and a sensor gateway. Each module communicates with each other through RF (Radio frequency) communication. The ambient intelligence display includes an ultrasonic receiver and a PIR sensor for motion detection. In particular, this system selects and processes algorithms such as smoothing or linear regression for current input data processing dynamically through judgment process that is determined using the previous reliable data stored in a queue. In addition, we implemented GUI software with JAVA for real time location tracking and an ambient intelligence display.

Structures of mesophilic and extremophilic citrate synthases reveal rigidity and flexibility for function.

PubMed

Wells, Stephen A; Crennell, Susan J; Danson, Michael J

2014-10-01

Citrate synthase (CS) catalyses the entry of carbon into the citric acid cycle and is highly-conserved structurally across the tree of life. Crystal structures of dimeric CSs are known in both "open" and "closed" forms, which differ by a substantial domain motion that closes the substrate-binding clefts. We explore both the static rigidity and the dynamic flexibility of CS structures from mesophilic and extremophilic organisms from all three evolutionary domains. The computational expense of this wide-ranging exploration is kept to a minimum by the use of rigidity analysis and rapid all-atom simulations of flexible motion, combining geometric simulation and elastic network modeling. CS structures from thermophiles display increased structural rigidity compared with the mesophilic enzyme. A CS structure from a psychrophile, stabilized by strong ionic interactions, appears to display likewise increased rigidity in conventional rigidity analysis; however, a novel modified analysis, taking into account the weakening of the hydrophobic effect at low temperatures, shows a more appropriate decreased rigidity. These rigidity variations do not, however, affect the character of the flexible dynamics, which are well conserved across all the structures studied. Simulation trajectories not only duplicate the crystallographically observed symmetric open-to-closed transitions, but also identify motions describing a previously unidentified antisymmetric functional motion. This antisymmetric motion would not be directly observed in crystallography but is revealed as an intrinsic property of the CS structure by modeling of flexible motion. This suggests that the functional motion closing the binding clefts in CS may be independent rather than symmetric and cooperative. © 2014 Wiley Periodicals, Inc.

Review – Quantum Dots and Their Application in Lighting, Displays, and Biology

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

Frecker, Talitha; Bailey, Danielle; Arzeta-Ferrer, Xochitl

2015-08-18

In this review, we focus on the advancement of white light emitting nanocrystals, their usage as the emissive layer in LEDs and display backlights, and examine the increased efficiency and longevity of quantum dots based colored LEDs. In addition, we also explore recent discoveries on quantum dots as biological labels, dynamic trackers, and applications in drug delivery.

Optimizing real-time Web-based user interfaces for observatories

NASA Astrophysics Data System (ADS)

Gibson, J. Duane; Pickering, Timothy E.; Porter, Dallan; Schaller, Skip

2008-08-01

In using common HTML/Ajax approaches for web-based data presentation and telescope control user interfaces at the MMT Observatory (MMTO), we rapidly were confronted with web browser performance issues. Much of the operational data at the MMTO is highly dynamic and is constantly changing during normal operations. Status of telescope subsystems must be displayed with minimal latency to telescope operators and other users. A major motivation of migrating toward web-based applications at the MMTO is to provide easy access to current and past observatory subsystem data for a wide variety of users on their favorite operating system through a familiar interface, their web browser. Performance issues, especially for user interfaces that control telescope subsystems, led to investigations of more efficient use of HTML/Ajax and web server technologies as well as other web-based technologies, such as Java and Flash/Flex. The results presented here focus on techniques for optimizing HTML/Ajax web applications with near real-time data display. This study indicates that direct modification of the contents or "nodeValue" attribute of text nodes is the most efficient method of updating data values displayed on a web page. Other optimization techniques are discussed for web-based applications that display highly dynamic data.

Long-range correlations and patterns of recurrence in children and adults' attention to hierarchical displays

PubMed Central

Castillo, Ramon D.; Kloos, Heidi; Holden, John G.; Richardson, Michael J.

2015-01-01

In order to make sense of a scene, a person must pay attention to several levels of nested order, ranging from the most differentiated details of the display to the integrated whole. In adults, research shows that the processes of integration and differentiation have the signature of self-organization. Does the same hold for children? The current study addresses this question with children between 6 and 9 years of age, using two tasks that require attention to hierarchical displays. A group of adults were tested as well, for control purposes. To get at the question of self-organization, reaction times were submitted to a detrended fluctuation analysis and a recurrence quantification analysis. H exponents show a long-range correlations (1/f noise), and recurrence measures (percent determinism, maximum line, entropy, and trend), show a deterministic structure of variability being characteristic of self-organizing systems. Findings are discussed in terms of organism-environment coupling that gives rise to fluid attention to hierarchical displays. PMID:25999862

Fast-scan EM with digital image processing for dynamic experiments

Treesearch

C.W. McMillin; F.C. Billingsley; R.E. Frazer

1974-01-01

The recent introduction of accessory instrumentation capable of display at television scan rates suggests a broadened application for the scanning electron microscope- the direct observation of motion (dynamic events) at magnifications otherwise unattainable. In one illustrative experiment, the transverse surface of southern pine was observed when subjected to large...

Fast-scan em with digital image processing for dynamic experiments

Treesearch

Charles W. McMillin; Fred C. Billingsley; Robert E. Frazer

1973-01-01

The recent introduction of accessory instrumentation capable of display at television scan rates suggests a broadened application for the scanning electron microscope - the direct observation of motion (dynamic events) at magnifactions otherwise unattainable. In one illustrative experiment, the transverse surface of southern pine was observed when subjected to large...

Improving Quality in Education: Dynamic Approaches to School Improvement

ERIC Educational Resources Information Center

Creemers, Bert P. M.; Kyriakides, Leonidas

2011-01-01

This book explores an approach to school improvement that merges the traditions of educational effectiveness research and school improvement efforts. It displays how the dynamic model, which is theoretical and empirically validated, can be used in both traditions. Each chapter integrates evidence from international and national studies, showing…

Dynamics Explorer twin spacecraft under evaluation tests

NASA Technical Reports Server (NTRS)

Redmond, C.

1981-01-01

The Dynamics Explorer A and B satellites designed to explore the interactive processes occuring between the magnetosphere and Earth's ionosphere, upper atmosphere, and plasmasphere are described. Effects of these interactions, satellite orbits, data collecting antennas, solar power systems, axes, configurations, and Earth based command, control and data display systems are mentioned.

Dynamic Displays of Data

ERIC Educational Resources Information Center

Angotti, Robin

2017-01-01

This article describes Gapminder, a dynamic time-series graph that can be found at http://www.gapminder.org. Gapminder was created by a team of developers (Rosling, Ronnlund, and Rosling 2005) to create beautiful, interactive graphs of otherwise lifeless numbers. Their goal is increased use and understanding of statistics and data that…

Display Tactics

ERIC Educational Resources Information Center

Tetlow, Linda

2009-01-01

Display took a wide variety of forms ranging from students presenting their initial planning and thought processes, to displays of their finished work, and their suggestions for extending the task should they, or others, have time to return to it in the future. A variety of different media were used from traditional posters in many shapes and…

Advances in Software Tools for Pre-processing and Post-processing of Overset Grid Computations

NASA Technical Reports Server (NTRS)

Chan, William M.

2004-01-01

Recent developments in three pieces of software for performing pre-processing and post-processing work on numerical computations using overset grids are presented. The first is the OVERGRID graphical interface which provides a unified environment for the visualization, manipulation, generation and diagnostics of geometry and grids. Modules are also available for automatic boundary conditions detection, flow solver input preparation, multiple component dynamics input preparation and dynamics animation, simple solution viewing for moving components, and debris trajectory analysis input preparation. The second is a grid generation script library that enables rapid creation of grid generation scripts. A sample of recent applications will be described. The third is the OVERPLOT graphical interface for displaying and analyzing history files generated by the flow solver. Data displayed include residuals, component forces and moments, number of supersonic and reverse flow points, and various dynamics parameters.

Climatic and density influences on recruitment in an irruptive population of Roosevelt elk

USGS Publications Warehouse

Starns, Heath D.; Ricca, Mark A.; Duarte, Adam; Weckerly, Floyd W.

2014-01-01

Current paradigms of ungulate population ecology recognize that density-dependent and independent mechanisms are not always mutually exclusive. Long-term data sets are necessary to assess the relative strength of each mechanism, especially when populations display irruptive dynamics. Using an 18-year time series of population abundances of Roosevelt elk (Cervus elaphus roosevelti) inhabiting Redwood National Park in northwestern California we assessed the influence of population size and climatic variation on elk recruitment and whether irruptive dynamics occurred. An information-theoretic model selection analysis indicated that abundance lagged 2 years and neither climatic factors nor a mix of abundance and climatic factors influenced elk recruitment. However, density-dependent recruitment differed between when the population was declining and when the population increased and then stabilized at an abundance lower than at the start of the decline. The population displayed irruptive dynamics.

Structural connectome topology relates to regional BOLD signal dynamics in the mouse brain

NASA Astrophysics Data System (ADS)

Sethi, Sarab S.; Zerbi, Valerio; Wenderoth, Nicole; Fornito, Alex; Fulcher, Ben D.

2017-04-01

Brain dynamics are thought to unfold on a network determined by the pattern of axonal connections linking pairs of neuronal elements; the so-called connectome. Prior work has indicated that structural brain connectivity constrains pairwise correlations of brain dynamics ("functional connectivity"), but it is not known whether inter-regional axonal connectivity is related to the intrinsic dynamics of individual brain areas. Here we investigate this relationship using a weighted, directed mesoscale mouse connectome from the Allen Mouse Brain Connectivity Atlas and resting state functional MRI (rs-fMRI) time-series data measured in 184 brain regions in eighteen anesthetized mice. For each brain region, we measured degree, betweenness, and clustering coefficient from weighted and unweighted, and directed and undirected versions of the connectome. We then characterized the univariate rs-fMRI dynamics in each brain region by computing 6930 time-series properties using the time-series analysis toolbox, hctsa. After correcting for regional volume variations, strong and robust correlations between structural connectivity properties and rs-fMRI dynamics were found only when edge weights were accounted for, and were associated with variations in the autocorrelation properties of the rs-fMRI signal. The strongest relationships were found for weighted in-degree, which was positively correlated to the autocorrelation of fMRI time series at time lag τ = 34 s (partial Spearman correlation ρ = 0.58 ), as well as a range of related measures such as relative high frequency power (f > 0.4 Hz: ρ = - 0.43 ). Our results indicate that the topology of inter-regional axonal connections of the mouse brain is closely related to intrinsic, spontaneous dynamics such that regions with a greater aggregate strength of incoming projections display longer timescales of activity fluctuations.

Using the stereokinetic effect to convey depth - Computationally efficient depth-from-motion displays

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.; Proffitt, Dennis R.

1992-01-01

Recent developments in microelectronics have encouraged the use of 3D data bases to create compelling volumetric renderings of graphical objects. However, even with the computational capabilities of current-generation graphical systems, real-time displays of such objects are difficult, particularly when dynamic spatial transformations are involved. In this paper we discuss a type of visual stimulus (the stereokinetic effect display) that is computationally far less complex than a true three-dimensional transformation but yields an equally compelling depth impression, often perceptually indiscriminable from the true spatial transformation. Several possible applications for this technique are discussed (e.g., animating contour maps and air traffic control displays so as to evoke accurate depth percepts).

Software Aids In Graphical Depiction Of Flow Data

NASA Technical Reports Server (NTRS)

Stegeman, J. D.

1995-01-01

Interactive Data Display System (IDDS) computer program is graphical-display program designed to assist in visualization of three-dimensional flow in turbomachinery. Grid and simulation data files in PLOT3D format required for input. Able to unwrap volumetric data cone associated with centrifugal compressor and display results in easy-to-understand two- or three-dimensional plots. IDDS provides majority of visualization and analysis capability for Integrated Computational Fluid Dynamics and Experiment (ICE) system. IDDS invoked from any subsystem, or used as stand-alone package of display software. Generates contour, vector, shaded, x-y, and carpet plots. Written in C language. Input file format used by IDDS is that of PLOT3D (COSMIC item ARC-12782).

Stress Analyzer

NASA Technical Reports Server (NTRS)

1990-01-01

SPATE 900 Dynamic Stress Analyzer is an acronym for Stress Pattern Analysis by Thermal Emission. It detects stress-induced temperature changes in a structure and indicates the degree of stress. Ometron, Inc.'s SPATE 9000 consists of a scan unit and a data display. The scan unit contains an infrared channel focused on the test structure to collect thermal radiation, and a visual channel used to set up the scan area and interrogate the stress display. Stress data is produced by detecting minute temperature changes, down to one-thousandth of a degree Centigrade, resulting from the application to the structure of dynamic loading. The electronic data processing system correlates the temperature changes with a reference signal to determine stress level.

Chaotic behaviour of the Rossler model and its analysis by using bifurcations of limit cycles and chaotic attractors

NASA Astrophysics Data System (ADS)

Ibrahim, K. M.; Jamal, R. K.; Ali, F. H.

2018-05-01

The behaviour of certain dynamical nonlinear systems are described in term as chaos, i.e., systems’ variables change with the time, displaying very sensitivity to initial conditions of chaotic dynamics. In this paper, we study archetype systems of ordinary differential equations in two-dimensional phase spaces of the Rössler model. A system displays continuous time chaos and is explained by three coupled nonlinear differential equations. We study its characteristics and determine the control parameters that lead to different behavior of the system output, periodic, quasi-periodic and chaos. The time series, attractor, Fast Fourier Transformation and bifurcation diagram for different values have been described.

Large-Scale Simulation Network Design Study

DTIC Science & Technology

1983-10-01

video displays: three for the tank commander, three for the driver, one for the loader, and one for the gunner. The solid angles subtended by these...Newman Inc Range Sortr This process sorts the expanded display lists into range order for drawing according to the "painter’s algorithm’" The range sorter ...session could then be continued as soon as the network recovered. and the elapsed session time would not be wasted . The SimNet design is much more tolerant

A study of stress-induced electrical noise in thin wires of iron-based alloys

NASA Astrophysics Data System (ADS)

Segales, Lyndon Duarte

Electrical noise measurements are utilized in many studies of fluctuation phenomena because they have shown to be useful in extracting information on slow kinetic processes. Slow moving random fluctuations that occur in solids will either affect the current in the sample or the resistivity of the sample, thereby creating electrical noise. The noise is analyzed in the frequency domain for its statistical variables. In the past twenty years, noise measurements on samples under stress have received considerable interests because the method is non-destructive and they provide some insight into the mechanical dynamics of materials not available to other conventional methods. The dynamics of the fluctuation in response to the applied stress, however, has not been clearly identified in recent studies. Most of these studies were performed on thin films of metals and their broadband 1/f noise was analyzed in response to stress. A narrowband stress-induced electrical noise in thin wires of iron-based alloys under tensile stress will be presented in the results of this thesis. The voltage noise displayed narrowband peaks in the low frequency region of the power spectrum that were ˜104 times the background noise. The electrical response to stress was analyzed in terms of the root mean squared (rms) voltage (Vrms) of the noise signal over a 50 Hz bandwidth. The information obtained from such measurements is independent of other non-destructive testing methods and is therefore a useful probe of the stress-strain dynamics in metals and alloys. The magnitude of the voltage noise as function of stress and temperature displayed a maximum over a narrow range. This is a qualitative indication of an activation process, similar to the maxima observed in studies of internal friction as a function of temperature. It is proposed that this noise signal is due to piezo resistance fluctuations as a result of stress-induced re-orientation of defects, similar to the Zener relaxation of solute atoms in a solid solution.

Vegetation engineers marsh morphology through multiple competing stable states

NASA Astrophysics Data System (ADS)

Marani, Marco; Da Lio, Cristina; D'Alpaos, Andrea

2013-02-01

Marshes display impressive biogeomorphic features, such as zonation, a mosaic of extensive vegetation patches of rather uniform composition, exhibiting sharp transitions in the presence of extremely small topographic gradients. Although generally associated with the accretion processes necessary for marshes to keep up with relative sea level rise, competing environmental constraints, and ecologic controls, zonation is still poorly understood in terms of the underlying biogeomorphic mechanisms. Here we find, through observations and modeling interpretation, that zonation is the result of coupled geomorphological-biological dynamics and that it stems from the ability of vegetation to actively engineer the landscape by tuning soil elevation within preferential ranges of optimal adaptation. We find multiple peaks in the frequency distribution of observed topographic elevation and identify them as the signature of biologic controls on geomorphodynamics through competing stable states modulated by the interplay of inorganic and organic deposition. Interestingly, the stable biogeomorphic equilibria correspond to suboptimal rates of biomass production, a result coherent with recent observations. The emerging biogeomorphic structures may display varying degrees of robustness to changes in the rate of sea level rise and sediment availability, with implications for the overall resilience of marsh ecosystems to climatic changes.

Vegetation engineers marsh morphology through multiple competing stable states

PubMed Central

Marani, Marco; Da Lio, Cristina; D’Alpaos, Andrea

2013-01-01

Marshes display impressive biogeomorphic features, such as zonation, a mosaic of extensive vegetation patches of rather uniform composition, exhibiting sharp transitions in the presence of extremely small topographic gradients. Although generally associated with the accretion processes necessary for marshes to keep up with relative sea level rise, competing environmental constraints, and ecologic controls, zonation is still poorly understood in terms of the underlying biogeomorphic mechanisms. Here we find, through observations and modeling interpretation, that zonation is the result of coupled geomorphological–biological dynamics and that it stems from the ability of vegetation to actively engineer the landscape by tuning soil elevation within preferential ranges of optimal adaptation. We find multiple peaks in the frequency distribution of observed topographic elevation and identify them as the signature of biologic controls on geomorphodynamics through competing stable states modulated by the interplay of inorganic and organic deposition. Interestingly, the stable biogeomorphic equilibria correspond to suboptimal rates of biomass production, a result coherent with recent observations. The emerging biogeomorphic structures may display varying degrees of robustness to changes in the rate of sea level rise and sediment availability, with implications for the overall resilience of marsh ecosystems to climatic changes. PMID:23401529

Enhancing Electrophoretic Display Lifetime: Thiol-Polybutadiene Evaporation Barrier Property Response to Network Microstructure

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

Cook, Caitlyn Christian

An evaporation barrier is required to enhance the lifetime of electrophoretic deposition (EPD) displays. As EPD functions on the basis of reversible deposition and resuspension of colloids suspended in a solvent, evaporation of the solvent ultimately leads to device failure. Incorporation of a thiol-polybutadiene elastomer into EPD displays enabled display lifetime surpassing six months in counting and catalyzed rigid display transition into a flexible package. Final flexible display transition to mass production compels an electronic-ink approach to encapsulate display suspension within an elastomer shell. Final thiol-polybutadiene photosensitive resin network microstructure was idealized to be dense, homogeneous, and expose an elasticmore » response to deformation. Research at hand details an approach to understanding microstructural change within display elastomers. Polybutadiene-based resin properties are modified via polymer chain structure, with and without added aromatic urethane methacrylate difunctionality, and in measuring network response to variation in thiol and initiator concentration. Dynamic mechanical analysis results signify that cross-linked segments within a difunctionalized polybutadiene network were on average eight times more elastically active than that of linked segments within a non-functionalized polybutadiene network. Difunctionalized polybutadiene samples also showed a 2.5 times greater maximum elastic modulus than non-functionalized samples. Hybrid polymer composed of both polybutadiene chains encompassed TE-2000 stiffness and B-1000 elasticity for use in encapsulating display suspension. Later experiments measured kinetic and rheological response due to alteration in dithiol cross-linker chain length via real time Fourier transform infrared spectroscopy and real-time dynamic rheology. Distinct differences were discovered between dithiol resin systems, as maximum thiol conversion achieved in short and long chain length dithiols was 86% and 11%, respectively. Oscillatory real-time rheological experiments confirmed a more uniform network to better dissipate applied shear in short chain length dithiol systems, as long chain length dithiols relayed a steep internal stress build-up due to less cross-links and chain entanglements. Thorough understanding of network formation aids the production of a stronger and impermeable elastomeric barrier for preservation of EPD displays.« less

A Markovian Entropy Measure for the Analysis of Calcium Activity Time Series.

PubMed

Marken, John P; Halleran, Andrew D; Rahman, Atiqur; Odorizzi, Laura; LeFew, Michael C; Golino, Caroline A; Kemper, Peter; Saha, Margaret S

2016-01-01

Methods to analyze the dynamics of calcium activity often rely on visually distinguishable features in time series data such as spikes, waves, or oscillations. However, systems such as the developing nervous system display a complex, irregular type of calcium activity which makes the use of such methods less appropriate. Instead, for such systems there exists a class of methods (including information theoretic, power spectral, and fractal analysis approaches) which use more fundamental properties of the time series to analyze the observed calcium dynamics. We present a new analysis method in this class, the Markovian Entropy measure, which is an easily implementable calcium time series analysis method which represents the observed calcium activity as a realization of a Markov Process and describes its dynamics in terms of the level of predictability underlying the transitions between the states of the process. We applied our and other commonly used calcium analysis methods on a dataset from Xenopus laevis neural progenitors which displays irregular calcium activity and a dataset from murine synaptic neurons which displays activity time series that are well-described by visually-distinguishable features. We find that the Markovian Entropy measure is able to distinguish between biologically distinct populations in both datasets, and that it can separate biologically distinct populations to a greater extent than other methods in the dataset exhibiting irregular calcium activity. These results support the benefit of using the Markovian Entropy measure to analyze calcium dynamics, particularly for studies using time series data which do not exhibit easily distinguishable features.

Rigid Facial Motion Influences Featural, But Not Holistic, Face Processing

PubMed Central

Xiao, Naiqi; Quinn, Paul C.; Ge, Liezhong; Lee, Kang

2012-01-01

We report three experiments in which we investigated the effect of rigid facial motion on face processing. Specifically, we used the face composite effect to examine whether rigid facial motion influences primarily featural or holistic processing of faces. In Experiments 1, 2, and 3, participants were first familiarized with dynamic displays in which a target face turned from one side to another; then at test, participants judged whether the top half of a composite face (the top half of the target face aligned or misaligned with the bottom half of a foil face) belonged to the target face. We compared performance in the dynamic condition to various static control conditions in Experiments 1, 2, and 3, which differed from each other in terms of the display order of the multiple static images or the inter stimulus interval (ISI) between the images. We found that the size of the face composite effect in the dynamic condition was significantly smaller than that in the static conditions. In other words, the dynamic face display influenced participants to process the target faces in a part-based manner and consequently their recognition of the upper portion of the composite face at test became less interfered with by the aligned lower part of the foil face. The findings from the present experiments provide the strongest evidence to date to suggest that the rigid facial motion mainly influences facial featural, but not holistic, processing. PMID:22342561

Recent developments in chaotic dynamics

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

Ott, E.

1994-02-01

Before the relatively recent wide acceptance of the existence of chaotic dynamics, many physicists and engineers were under the impression that simple systems could necessarily only display simple solutions. This feeling had been unintentionally reinforced by conventional college courses which emphasize linear dynamics (partly because that is the only case with nice general solutions). More recently, physical experiments and numerical examples have abundantly demonstrated how wrong this feeling is. A brief review of chaotic dynamics is presented. Topics discussed include basic concepts, recent developments, and applications.

Cassini/MIMI Measurements in Saturn's Magnetosphere and their Implications for Magnetospheric Dynamics

NASA Astrophysics Data System (ADS)

Mitchell, D. G.

2016-12-01

The Cassini spacecraft has been in orbit about Saturn since early July, 2004. In less than a year, on September 15, 2017, Cassini will plunge into Saturn's atmosphere, ending what has been a highly successful and interesting mission. As befitting a Planetary Division Flagship Mission, Cassini's science payload included instrumentation designed for a multitude of science objectives, from surfaces of moons to rings to atmospheres to Saturn's vast, fast-rotating magnetosphere. Saturn's magnetosphere exhibits considerable variability, both from inner magnetosphere to outer, and over time. Characterizing the dynamics of the magnetosphere has required the full range of energetic particles (measured by the magnetospheric imaging instrument, MIMI - https://saturn.jpl.nasa.gov/magnetospheric-imaging-instrument/), plasma (provided by the Cassini plasma spectrometer, CAPS), gas (ion and neutral mass spectrometer, INMS), magnetic fields (Cassini magnetometer, MAG), radio and plasma waves (radio and plasma wave science, RPWS), dust (Cassini Dust Analyzer, CDA), as well as ultraviolet, visible and infrared imaging (ultraviolet imaging spectrograph, UVIS; Cassini imaging subsystem ISS; visible and infrared mapping spectrometer, VIMS; Cassini composite infrared spectrometer, CIRS) and ionospheric sounding by the Cassini radio science subsystem (RSS). It has also required the full range of orbital geometries from equatorial to high inclination and all local times, as well as the full range of solar wind conditions, seasonal sun-Saturn configurations. In this talk we focus on the contributions of the MIMI instrument suite (CHEMS, LEMMS, and INCA) to our understanding of the dynamics of Saturn's magnetosphere. We will both review past work, and present recent observations from the high inclination orbits that precede the final stages of the Cassini mission, the sets of high inclination orbits that cross the equator just beyond the edge of the main ring system, and later cross between the inner edge of the main rings and Saturn's upper atmosphere. We highlight processes including radiation belt generation, particle precipitation into Titan's atmosphere, icy moon interactions, magnetotail reconnection, flux tube interchange, solar wind-driven dynamics, and connection to auroral displays.

The intra-day dynamics of affect, self-esteem, tiredness, and suicidality in Major Depression.

PubMed

Crowe, Eimear; Daly, Michael; Delaney, Liam; Carroll, Susan; Malone, Kevin M

2018-02-21

Despite growing interest in the temporal dynamics of Major Depressive Disorder (MDD), we know little about the intra-day fluctuations of key symptom constructs. In a study of momentary experience, the Experience Sampling Method captured the within-day dynamics of negative affect, positive affect, self-esteem, passive suicidality, and tiredness across clinical MDD (N= 31) and healthy control groups (N= 33). Ten symptom measures were taken per day over 6 days (N= 2231 observations). Daily dynamics were modeled via intra-day time-trends, variability, and instability in symptoms. MDD participants showed significantly increased variability and instability in negative affect, positive affect, self-esteem, and suicidality. Significantly different time-trends were found in positive affect (increased diurnal variation and an inverted U-shaped pattern in MDD, compared to a positive linear trend in controls) and tiredness (decreased diurnal variation in MDD). In the MDD group only, passive suicidality displayed a negative linear trend and self-esteem displayed a quadratic inverted U trend. MDD and control participants thus showed distinct dynamic profiles in all symptoms measured. As well as the overall severity of symptoms, intra-day dynamics appear to define the experience of MDD symptoms. Copyright © 2018 Elsevier B.V. All rights reserved.

Dynamics of backlight luminance for using smartphone in dark environment

NASA Astrophysics Data System (ADS)

Na, Nooree; Jang, Jiho; Suk, Hyeon-Jeong

2014-02-01

This study developed dynamic backlight luminance, which gradually changes as time passes for comfortable use of a smartphone display in a dark environment. The study was carried out in two stages. In the first stage, a user test was conducted to identify the optimal luminance by assessing the facial squint level, subjective glare evaluation, eye blink frequency and users' subjective preferences. Based on the results of the user test, the dynamics of backlight luminance was designed. It has two levels of luminance: the optimal level for initial viewing to avoid sudden glare or fatigue to users' eyes, and the optimal level for constant viewing, which is comfortable, but also bright enough for constant reading of the displayed material. The luminance for initial viewing starts from 10 cd/m2, and it gradually increases to 40 cd/m2 for users' visual comfort at constant viewing for 20 seconds; In the second stage, a validation test on dynamics of backlight luminance was conducted to verify the effectiveness of the developed dynamics. It involving users' subjective preferences, eye blink frequency, and brainwave analysis using the electroencephalogram (EEG) to confirm that the proposed dynamic backlighting enhances users' visual comfort and visual cognition, particularly for using smartphones in a dark environment.